SUMMARY

The present disclosure generally relates to peelable adhesive articles that are capable of attaching or adhering to a substrate to mount an item to the substrate and that can be removed from the substrate without causing damage to the substrate or the mounted item. The peelable adhesive articles generally include at least one adhesive layer applied to a backing substrate. The present disclosure also generally relates to methods of making and using such adhesive articles.

Existing peelable adhesive products often do not work well on various surfaces, including, for example, painted surfaces and rough surfaces (e.g., drywall). Additionally, the existing peelable products can exhibit low shear strength and thus can hold little weight or alternatively require a relatively thick construction, which can cause an increase in the potential for damage when such products are removed from an adherend. Paper and other fibrous surfaces are particularly susceptible to damage from typical mounting adhesive compositions. Attempts to mitigate damage on either the paper or the mounting surface normally result in adhesive articles that have compromised adhesion or shear holding strength, for example. Even with modifications to the backing materials or the adhesive compositions, the present inventors recognized that certain delicate surfaces (e.g., paper and drywall) still experienced visible damage despite such modifications. As such, the inventors of the present disclosure sought to formulate mounting products and/or adhesive articles with at least one of higher shear strength, ability to work well on painted or rough surfaces, and/or that are capable of consistently holding higher weights, all without damaging the substrate to which they are applied.

The present inventors discovered certain acrylic microsphere adhesive compositions can balance acceptable shear strength and peel adhesion with damage-free removal. Moreover, these adhesive compositions may be applied to suitable backing substrate at comparatively higher coating weights, leading to more consistent adhesion and higher weight holding capacity.

In one aspect the present disclosure provides pressure -sensitive adhesive compositions that contain polymer microspheres with an average particle size of 20 pm to 300 pm. These polymer microspheres are synthesized using the disclosed suspension polymerization techniques and include a monomer composition including at least one (meth)acrylate monomer, typically at least one structural isomer of a secondary methacrylate. The disclosed pressure-sensitive adhesive compositions when used, for example, in a mounting article, desirably provide holding power to, low surface energy adhesion to, and excellent damage-free removal from painted or other delicate surfaces.

In another aspect, provided are methods of making an adhesive article, the method comprising: forming an aqueous polymerizable pre-adhesive reaction mixture according to the present disclosure; polymerizing the monomers in the pre-adhesive reaction mixture to form a polymerized mixture, where the average particle size of polymers in the polymerized mixture is 20 pm to 300 pm, optionally 30 pm to 100 mih; coating the polymerized mixture onto a support to form a coated mixture; and drying the coated mixture. In some embodiments, the method further includes the step of adding a binder to the polymerized mixture.

The terms "polymer" and "polymeric material" include, but are not limited to, organic copolymers, such as for example, block, graft (including starblock), random and alternating copolymers, and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic symmetries. The polymers can be homopolymers, copolymers, terpolymers, etc. Copolymer is used herein to encompass polymers made from two or more different monomers, including terpolymers, tetrapolymers, etc. The term polymer and/or copolymer is used regardless of the molecular weight and includes what is sometimes referred to as an oligomer.

Pressure -sensitive adhesive compositions are well known to those of ordinary skill in the art to possess properties including the following: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be cleanly removable from the adherend. Materials that have been found to function well as pressure sensitive adhesives are polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear holding power. Obtaining the proper balance of properties is not a simple process.

The terms "glass transition temperature" and "Tg" are used interchangeably. Typically, Tg values are measured using Dynamic Mechanical Analysis (“DMA”), unless otherwise noted.

The term "room temperature" refers to ambient temperature, generally 20-23 °C, unless otherwise noted.

The term "high Tg monomer" refers to a monomer or monomeric unit that has a glass transition temperature of at least 25 °C, at least 35 °C, or at least 50 °C. when homopolymerized.

The term "(meth)acrylate" refers to monomeric acrylic or methacrylic esters of alcohols. Acrylate and methacrylate monomers are referred to collectively herein as "(meth)acrylates". Polymers described as being "(meth)acrylate-based" are polymers or copolymers prepared primarily (greater than 50% by weight (wt-%), greater than 60 wt-%, greater than 70 wt-%, greater than 80 wt-%, greater than 90 wt-%, greater than 95 wt-%, or 100 wt-%) from (meth)acrylate monomers and may include additional ethylenically unsaturated monomers such as various (meth)acrylamide monomers or various vinyl monomers that do not have a \(meth)acryloyl group.

As used herein, the terms "polymerizable" or "curable" are applied to the compounds, also called "monomers," that are polymerizable and/or crosslinkable as a result of initiation by thermal decomposition, redox reaction, or photolysis. Such compounds have at least one alpha, beta-unsaturated site (i.e.. an ethylenically unsaturated site). In some embodiments, monomers having more than one alpha, beta-unsaturated site are termed "crosslinkers," but it will be understood that the term "monomer" includes, as appropriate in context, compounds having more than one such site.

As used herein, the term "adhesive composition" or like term includes (1) at least three structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or C¾, (2) a stabilizer, and (3) one or more additional components blended therewith, wherein the adhesive composition is typically a pressure sensitive adhesive composition. The additional components typically include at least one of a binder and a rheology modifier, though other components and combinations of components may be used.

As used herein, the term "substantial" or "substantially" means with relatively minor fluctuations or aberrations from the stated property, value, range of values, content, formula, and the like, and does not exclude the presence of additional materials, broader range values, and the like which do not materially affect the desired characteristics of a given composition, article, product, or method.

Herein, the terms "comprises" and "includes" and variations thereof do not have a limiting meaning where these terms appear in the description and claims. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements. By "consisting of' is meant including, and limited to, whatever follows the phrase "consisting of' Thus, the phrase "consisting of' indicates that the listed elements are required or mandatory, and that no other elements may be present. By "consisting essentially of is meant including any elements listed after the phrase, and limited to other elements that do not interfere with or contribute to the activity or action specified in the disclosure for the listed elements. Thus, the phrase "consisting essentially of' indicates that the listed elements are required or mandatory, but that other elements are optional and may or may not be present depending upon whether or not they materially affect the activity or action of the listed elements.

The words "preferred" and "preferably" refer to claims of the disclosure that may afford certain benefits, under certain circumstances. However, other claims may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred claims does not imply that other claims are not useful and is not intended to exclude other claims from the scope of the disclosure.

In this application, terms such as "a", "an", and "the" are not intended to refer to only a singular entity but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one". The phrases "at least one of' and "includes at least one of followed by a list refers to any one of the items in the list and any combination of two or more items in the list. As used herein, the term "or" is generally employed in its usual sense including "and/or" unless the content clearly dictates otherwise.

The term "and/or" means one or all of the listed elements or a combination of any two or more of the listed elements.

Also herein, all numbers are assumed to be modified by the term "about" and in certain embodiments, preferably, by the term "exactly." As used herein in connection with a measured quantity, the term "about" refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. Herein, "up to" a number (e.g., up to 50) includes the number (e.g., 50).

Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5).

The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples may be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list.

Features and advantages of the present disclosure will be further understood upon consideration of the detailed description as well as the appended claims.

DETAILED DESCRIPTION

Various embodiments and implementations will be described in detail. These embodiments should not be construed as limiting the scope of the present application in any manner, and changes and modifications may be made without departing from the spirit and scope of the inventions. Further, only some end uses have been discussed herein, but end uses not specifically described herein are included within the scope of the present application. As such, the scope of the present application should be determined by the claims.

The present disclosure generally relates to adhesive articles that can be peeled off a substrate without damage. As used herein, the term “peelable” means that the adhesive article can be removed from a substrate or surface by peeling at angle of between about 1° and about 180°. In some embodiments, the adhesive article can be removed from a substrate or surface by peeling at angle of between 30° to 120°. In some embodiments, the adhesive article can be removed from a substrate or surface by peeling at angle of at least about 35°. As such, the inventors of the present disclosure found adhesive mounting articles that can be adhered to and peeled from various substrates, including delicate surfaces, without causing damage. These adhesive mounting articles can hang or mount articles of various weights. As used herein, the terms “without damage” and “damage-free” or the like means the adhesive article can be separated from the substrate without causing visible damage to paints, coatings, resins, coverings, or the underlying substrate. Visible damage to the substrates can be in the form of, for example, scratching, tearing, delaminating, breaking, crumbling, straining, and the like to any layers of the substrate. Visible damage can also be discoloration, weakening, changes in gloss, changes in haze, or other changes in appearance of the substrate.

Mounting articles of the present disclosure generally include a support substrate (i.e., a backing) having first and second opposed major surfaces. An adhesive composition including polymer microspheres is disposed on either one or both of the major surfaces. The adhesive layers can be the same as one another or disparate from one another. Disparate, in this context, is used to describe substantial differences in composition or adhesive performance. Adhesive layers can each be a single layer or can be multilayer. Adhesive layers can each be continuous or discontinuous (e.g., patterned) across the major surfaces of the backing. The available bond areas of the major surfaces are used to couple the adhesive article to, for example, a wall surface or an item to be mounted. In other exemplary embodiments, an adhesive article may lack an adhesive layer on the second major surface. The thickness of the adhesive layer(s) is not particularly limited, but the thickness is typically substantially continuous across at least the major surfaces of the backing. In typical embodiments, one or both adhesive layers have a thickness of between about 1 mil and about 3 mils. The thickness of a given adhesive layer may be different from the other or the same. In certain embodiments, one adhesive layer may be applied at a greater coating weight than the other. The disparity in coating weight and/or layer thickness can allow the mounting article to have preferential adhesion to a given substrate (e.g., either the mounting surface or the mounted item).

Constituent elements of the adhesive articles described herein are explored in more detail below.

Adhesive Layerfs)

The present disclosure provides adhesive compositions that include polymer microspheres with an average particle size of 20 pm to 300 pm. The polymer microspheres are synthesized using the disclosed suspension polymerization techniques and are (meth)acrylate based. Typically, the polymer microspheres include at least one or at least three structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or ϋ¼. Aqueous polymerizable pre adhesive reaction mixtures (also referred to as "aqueous pre-adhesive reaction mixtures" or "pre-adhesive reaction mixture" or "polymerizable pre-adhesive reaction mixtures" or like term) are also provided that include water, the monomer composition used to form the polymer microspheres, and a stabilizer. The monomer composition contains at least three structural isomers of a secondary (meth)acrylate of Formula

(I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CH ₃ , and optionally one or more high Tg monomers. Further, the polymerized products of the pre-adhesive reaction mixtures are provided, as well as methods of preparation of the adhesive compositions wherein the polymer microspheres are formed in the presence of the stabilizer and optionally in the presence of dispersed particles (e.g., a latex).

Monomer Composition

Polymer microspheres of the present disclosure can be copolymers including the reaction products of polymerizable monomers, i.e., monomer composition, in particular, structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CFR Methods for preparing such polymerizable monomers of Formula (I) are known to those of ordinary skill in the relevant arts and are described in U.S. Pat. No. 9,102,774 (Clapper et al .), the contents of which are hereby incorporated by reference in their entirety. The aqueous pre-adhesive reaction mixtures, the polymerized products of the aqueous pre-adhesive reaction mixtures, and the adhesive compositions of the present disclosure include at least one, typically at least three structural isomers of a secondary (meth)acrylate of Formula (I).

Other monomers potentially useful in creating the polymer microspheres of the present disclosure include alkyl acrylates such as butyl acrylate, ethyl acrylate, methyl acrylate, and 2- ethylhexylacrylate, alkyl methacrylates such as methyl methacrylate and butyl methacrylate, polar comonomers such as acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, N-tertiary octylacrylamide, acrylonitrile, acrylamide, 1 -vinyl-2 -pyrrolidone, sodium vinyl sulfonate, vinyl esters such as vinyl acetate, vinyl propionate, vinyl neodecanoate, vinyl stearate and vinyl pivalate. In some embodiments, the monomer composition may further include one or more additional monomers that copolymerizes with and/or crosslinks acrylates. The additional monomer(s) are commonly selected to provide a reduced level of measurable adhesion to a selected substrate while still providing the level of tack of the adhesive polymer (i.e., the microsphere polymer), relative to the adhesive polymer without the one or more additional monomers. In other embodiments, the additional monomer(s) are selected to impart to the resulting adhesive polymer with a reduced level of tack while maintaining a substantially constant level of adhesion to a selected substrate, relative to the polymer without the one or more additional monomers. In still other embodiments, the additional monomer(s) are selected to impart to the resulting adhesive polymer an increased level of tack while maintaining a substantially constant level of adhesion to a selected substrate relative to the adhesive polymer without the one or more additional monomers. In some embodiments, the monomer that copolymerizes with acrylates may be a high Tg monomer.

In some embodiments, the high Tg monomers are selected from one or more high Tg monomers having a (meth)acryloyl group (i.e.. a single (meth)acryloyl group). When used in combination with the (meth)acrylate monomers of Formula (I) described herein, such high Tg monomers may increase the overall Tg of the polymer and have been found to increase the modulus of polymers to which they are added, thus allowing characteristics of the material, such as, for example, the polymer’s softness, to be modified.

Example high Tg monomers having a single (meth)acryloyl group include, but are not limited to, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl (meth)acrylate, cyclohexyl methacrylate, isobomyl (meth)acrylate, stearyl (meth)acrylate, phenyl acrylate, benzyl methacrylate, 3,3,5 trimethylcyclohexyl (meth)acrylate, 2-phenoxyethyl methacrylate, and mixtures thereof. Suitable high Tg monomers for use in monomer compositions of the present disclosure generally have a homopolymer Tg of at least 25 °C, optionally of at least 35 °C, or optionally of at least 50 °CI

For certain mounting articles intended to be used on delicate surfaces, it can be advantageous to use high Tg monomers that lack additional heteroatom polarity independent of (meth)acrylate functionality. Such monomers are considered as “nonpolar” herein, despite any polarity stemming from a (meth)acrylate. Though not wishing to be bound by theory, the use of monomers that are not nonpolar has been observed to increase the potential for damage upon removal of an adhesive from at least paper and cardboard. Suitable nonpolar, high Tg monomers include, but are not limited to, isobomyl acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and styrene. In some presently preferred examples, the high Tg monomer is isobomyl acrylate.

In other embodiments, the high Tg monomers are selected from one or more high Tg monomers having two or more (meth)acryloyl groups. An exemplary high Tg monomer having two or more (meth)acryloyl groups is hexane diol diacrylate (HDDA), though other high Tg difunctional (meth)acrylates including, but not limited to, trimethylolpropane triacrylatecan also be used. The (meth)acrylate monomers having two or more (meth)acryloyl groups may be used alone or in combination with high Tg monomers having a single (meth)acryloyl group.

In some embodiments, the high Tg monomers may be present in a pre-adhesive reaction mixture in an amount of greater than 0 wt.%, or at least 0.01, wt.%, at least 0.1 wt%, or at least 1 wt.%, or at least 2 wt.%, or at least 3 wt.%, or at least 5 wt.%, based on the total weight of the monomers in the pre adhesive reaction mixture. In some embodiments, the high Tg monomers may be present in a pre adhesive reaction mixture in an amount of up to 40 wt.%, or up to 20 wt.%, or up to 15 wt.%, or up to 10 wt.%, based on the total weight of the monomers in the pre-adhesive reaction mixture. Various intermediate levels are also possible, such as 4 wt.%, 6 wt.%, 11 wt.%, 13 wt.%, 16 wt.%, 19 wt.%, 25 wt.%, 35wt.% and all other such individual values represented by, for example, 1 wt.% increments between 0 wt-% and 40 wt-%, and in any range spanning these individual values in, for example, 1 wt.% increments, such as 2 wt.% to 4 wt.%, 11 wt.% to 20 wt.%, 7 wt.% to 17 wt.%, or 0.1 wt.% increments, and the like. These amounts also apply to the amounts of reacted monomeric units in a microsphere polymer of the present disclosure, wherein the weight percentages are based on the weight of the polymer. Typically, though not exclusively, the high Tg monomers having two or more (meth)acryloyl groups are present in an amount no greater than 1 wt.%, based on the total weight of the monomers in the pre adhesive reaction mixture.

In embodiments of the monomer composition including both (meth)acrylates of Formula (I) and high Tg monomers, the mass ratio of (meth)acrylates of Formula (I):high Tg monomer in the monomer composition is typically 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1 13:1, 12:1, 11:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, or 4: 1. In some preferred embodiments, the mass ratio of (meth)acrylates of Formula (I):high Tg monomer in the monomer composition is at least 9:1 or at least 19:1.

In some embodiments, the monomer composition is present in the aqueous polymerizable pre adhesive reaction mixture in an amount of at least 2 weight percent (wt.%), or at least 4 wt.%, or at least 6 wt.%, or at least 8 wt.%, or at least 10 wt.%, based on the total weight of the aqueous polymerizable pre adhesive reaction mixture. In some embodiments, the monomer composition is present in the aqueous polymerizable pre-adhesive reaction mixture in an amount of up to 60 wt.%, or up to 55 wt.%, or up to 50 wt.%, or up to 40 wt.%, or up to 35 wt.%, or up to 30 wt.%, based on the total weight of the monomers in the pre-adhesive reaction mixture. Various intermediate levels are also possible, such as 3 wt.%, 5 wt.%, 7 wt.%, 9 wt.%, and all other such individual values represented by, for example, 1 wt.% increments between 2 wt.% and 60 wt.%, and in any range spanning these individual values in, for example, 1 wt.% increments, such as 2 wt.% to 4 wt.%, 7 wt.% to 60 wt.%, 20 wt.% to 25 wt.%, and the like.

Depending on the solubility of these monomers in water, the high Tg monomers can be dissolved in water, dispersed in water, or both.

Stabilizer The aqueous pre-adhesive reaction mixtures, the polymerized products of the aqueous pre adhesive reaction mixtures, and the adhesive compositions of the present disclosure include one or more stabilizers. The stabilizers can be referred to as being "internally incorporated," which means that the stabilizer is included in the polymerizable pre-adhesive reaction mixture and is present during the polymerization of the monomers used to form the microsphere polymers.

In some embodiments, a suspension of monomers is formed, and polymerization is carried out using thermal initiation of the polymerization reaction. The suspension is a water-in-oil or an oil-in-water suspension. In some such embodiments, the suspension is an oil-in-water suspension, wherein the monomers are stabilized in a bulk water phase by employing one or more stabilizers. Stabilizers useful in embodiments of the present disclosure can include, for example, inorganic stabilizers, surfactants, polymer additives, and combinations thereof.

In some embodiments, the stabilizer may be an inorganic stabilizer such as those used in Pickering emulsion polymerizations (e.g., colloidal silica).

In some embodiments, the stabilizer may be a polymer additive. Polymer additives useful in embodiments of the present disclosure may include, for example, polyacrylamide, polyvinyl alcohol, partially acetylated polyvinyl alcohol, hydroxyethyl cellulose, N-vinyl pyrrolidone, carboxymethyl cellulose, gum arabic, and mixtures thereof. In some embodiments, the polymer additive includes those sold under the trade name SUPERFLOC (e.g., SUPERFLOC N-300) by Kemira Oyj, Helsinki, Finland

In some embodiments, the stabilizer may be a surfactant. In some embodiments, the surfactant may be anionic, cationic, zwitterionic, or nonionic in nature and the structure thereof not otherwise particularly limited. In some embodiments, the surfactant is also a monomer and becomes incorporated within the polymer microsphere molecules. In other embodiments, the surfactant is present in the polymerization reaction vessel but is not incorporated into the polymer microsphere as a result of the polymerization reaction.

Non-limiting examples of anionic surfactants useful in embodiments of the present disclosure include sulfonates, sulfolipids, phospholipids, stearates, laurates and sulfates. Sulfates useful in embodiments of the present disclosure include sulfates sold under the trade name STEPANOL by the Stepan Company, Northfield IL, USA and HITENOL by the Montello, Inc., Tulsa, OK, USA, and mixtures thereof.

Non-limiting examples of nonionic surfactants useful in embodiments of the present disclosure include block copolymers of ethylene oxide and propylene oxide, such as those sold under the trade names PLURONIC, KOLLIPHOR, or TETRONIC, by the BASF Corporation of Charlotte, N.C., USA; ethoxylates formed by the reaction of ethylene oxide with a fatty alcohol, nonylphenol, dodecyl alcohol, and the like, including those sold under the trade name TRITON, by the Dow Chemical Company of Midland, Mich., USA; oleyl alcohol; sorbitan esters; alkylpolyglycosides such as decyl glucoside; sorbitan tristearate; and combinations of one or more thereof. Non-limiting examples of cationic surfactants useful in embodiments of the present disclosure include cocoalky lmethyl [polyoxyethylene (15)] ammonium chloride, benzalkonium chloride, cetrimonium bromide, demethyldioctadecylammonium chloride, lauryl methyl gluceth-10 hydroxypropyl diammonium chloride, tetramethylammonium hydroxide, monoalkyltrimethylammonium chlorides, monoalkyldimethylbenzylammonium chlorides, dialkylethylmethylammonium ethosulfates, trialky lmethylammonium chlorides, polyoxyethylenemonoalkylmethylammonium chlorides, and diquatemaryammonium chlorides; the ammonium functional surfactants sold by Akzo Nobel N.V. of Amsterdam, the Netherlands, under the trade names ETHOQUAD, ARQUAD, and DUOQUAD; and mixtures thereof.

In some embodiments, where a stabilizer is employed in an oil-in-water suspension polymerization reaction, it is employed in an amount of at least 0.01 wt.%, or at least 0.05 wt.%, or at least 0.1 wt.%, or at least 0.5 wt.%, or at least 1.0 wt.%, based on the total weight of solids in the aqueous polymerizable pre-adhesive reaction mixture. In some embodiments where a stabilizer is employed in an oil-in-water suspension polymerization reaction, it is employed in an amount of up to 5.0 wt.%, or up to 4.0 wt.%, based on the total weight of solids in the aqueous polymerizable pre -adhesive reaction mixture. Various intermediate levels are also useful, such as, for example, 1.1 wt-%, 1.2 wt-%, 1.3 wt-%, 1.4 wt- %, 1.5 wt-%, 1.6 wt-%, 1.7 wt-%, 1.8 wt-%, 1.9 wt-%, 2.1 wt-%, 2.2 wt-%, and all other such individual values represented by, for example, 0.01 wt.% increments between 0.01 and 5.0 wt.%, and in any range spanning these individual values in, for example, 0.1 wt.% increments, such as 2.3 wt.% to 4.6 wt.%, 4.5 wt.% to 4.7 wt.%, and the like.

Polymerization Processes

The polymerization of the aqueous polymerizable pre-adhesive reaction mixture may be carried out using conventional suspension polymerization techniques familiar to those of ordinary skill in the relevant arts.

In some embodiments where thermal decomposition is employed to initiate polymerization, suspension polymerization of the monomers employed to make the polymer microspheres of the present disclosure may be carried out by blending the stabilizer(s) with water to provide an aqueous phase and blending the monomer composition and a thermal initiator to provide an oil phase. The aqueous phase and the oil phase may then be combined and stirred vigorously enough to form a suspension. The suspension may generally be formed, for example, by stirring the combined aqueous and oil phases with a 3 -blade or 4-blade stirrer at a speed of 500 to 900 revolutions per minute (“rpm”). The suspension may then be heated to a temperature wherein decomposition of the initiator occurs at a rate suitable to sustain a suitable rate of polymerization ( e.g ., 60 °C).

Non-limiting examples of suitable thermal initiators include organic peroxides or azo compounds conventionally employed by those skilled in the art of thermal initiation of polymerization, such a dicumyl peroxide, benzoyl peroxide, or 2,2'-azo-bis(isobutyronitrile) (“AIBN”) and thermal initiators sold under the trade names LUPEROX by Arkema, Inc., King of Prussia, PA and VAZO by Chemours Canada Company, ON, Canada. The amount of initiator is typically in a range of 0.05 to 2 wt.% or in a range of 0.05 to 1 wt.%, or in a range of 0.05 to 0.5 wt% based on the total weight of monomers in the monomer composition.

In some embodiments, high-solids suspensions are formed, for example, at a solids content of at least 15 wt.%, or at least 25 wt.%, or at least 30 wt.%, solids in water. In some embodiments, high-solids suspensions are formed, for example, at a solids content of up to 60 wt.%, or up to 50 wt.%, solids in water. Various intermediate levels are useful, such as 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.%, 20 wt.%, 21 wt.%, 22 wt.%, 23 wt.%, 24 wt.%, 26 wt.%, 27 wt.%, and all other such individual values represented by, for example, 1 wt.% increments between 15 wt.% and 60 wt.% solids in water, and in any range spanning these individual values in, for example, 1 wt.% increments, such as 23 wt.% to 46 wt.%, 45 wt.% to 57 wt.%, and the like.

In preferred embodiments, solids formed during polymerization of the aqueous polymerizable pre-adhesive reaction mixture may have an average particle size 20 pm to 300 pm, optionally 30 pm to 100 pm as measured by conventional means using, for example, a Horiba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan).

In some embodiments, water is present in the polymerizable pre-adhesive reaction mixture, for example, in an amount of at least 39.99 wt.%, or at least 45 wt.%, or at least 50 wt.%. In some embodiments, water is present in the polymerizable pre-adhesive reaction mixture, for example, in an amount of up to 89.99 wt.%, or up to 80 wt.%, or up to 70 wt.%, or up to 60 wt.%.

In general, conditions of suspension polymerization and methodology employed are the same or similar to those employed in conventional suspension polymerization methods. In some embodiments, the oil-in-water suspension polymerization is carried out using thermal initiation. In such embodiments, one useful polymerization initiator is 2-2'-azobis(2,4-dimethylvaleronitrile), which is a water-insoluble initiator (obtained from Chemours Canada Company, ON, Canada). In some such embodiments, the temperature of the suspension is adjusted prior to and during the polymerization is 30 °C to 100 °C, or 40 °C to 80 °C, or 40 °C to 70 °C, or to 45 °C to 65 °C ( e.g ., 60 °C). In some embodiments, the peak temperature during the exotherm may reach as high as 110 °C, or as high as 90 °C, or as high as 75 °C.

Agitation of the suspension at elevated temperature is carried out for a suitable amount of time to decompose substantially all of the thermal initiator and react substantially all of the monomers added to the suspension to form a polymerized suspension. In some embodiments, elevated temperature is maintained for a period of 1 hour to 48 hours, 2 hours to 24 hours, or 4 hours to 18 hours, or 8 hours to 16 hours.

During polymerization, it may be necessary in some embodiments to add additional thermal initiator to complete the reaction of substantially all of the monomer content added to the reaction vessel. It will be appreciated that completion of the polymerization is achieved by careful adjustment of conditions, and standard analytical techniques, such as gas chromatographic analysis of residual monomer content, will inform the skilled artisan regarding the completion of polymerization.

In other embodiments, the polymerization may occur in an aqueous mixture that may also include an organic solvent. Examples of suitable organic solvents and solvent mixtures include, in various embodiments, one or more of ethanol, methanol, toluene, methyl ethyl ketone, ethyl acetate, isopropyl alcohol, tetrahydrofuran, 1 -methyl -2 -pyrrolidinone, 2-butanone, acetonitrile, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, dichloromethane, t-butanol, methyl isobutyl ketone, methyl t- butyl ether, and ethylene glycol. If used, no more than 10 wt-% organic solvent is used in the pre adhesive reaction mixtures described herein.

Adhesive Compositions and Coating

Adhesive compositions of the disclosure include a (meth)acrylate monomer composition, typically including structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CEE, a stabilizer, and optionally one or more additional components. Additional components may include, for example, one or more adhesion promoters, surfactants, antifouling agents, antiseptic or antibacterial agents, thermal or oxidative stabilizers, colorants, adjuvants, plasticizers, solvents, tackifiers, crosslinkers, or mixtures thereof. The antifouling agents may also include certain biocides typically used to kill/inhibit bacteria, fungi or algae. Exemplary biocides include iodopropynyl butyl carbamate compounds such as 3-iodo-2-propynyl butylcarbamate (IPBC), available as Preventol® MP100 from Lanxess Corporation, Pittsburgh, PA.

The crosslinkers can be monomeric, polymeric, oligomer, or a crosslinker package include combinations thereof. Monomers suitable for use as crosslinkers may be mono-, di-, tri-, or multi functional. Exemplary, but by no means exclusive, crosslinkers include 4-Benzoylphenyl acrylate, divinyl benzene, butanediol diacrylate, and hexanediol diacrylate. Other crosslinkers include certain of those high Tg monomers described above.

In some embodiments, a polymer having a monomer composition including structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CLL, a stabilizer, and optionally one or more additional components, at the end of an suspension polymerization process, is employed as the adhesive composition and is coated as-is onto one or more backing substrates to form an adhesive article. In preferred embodiments, the polymer may have an average particle size 20 pm to 300 pm, optionally 30 pm to 100 pm as measured by conventional means using, for example, a Horiba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan). In such embodiments, water and one or more surfactants employed in the polymerization will remain associated with the adhesive composition, along with any residual unreacted monomers or initiators. The adhesive composition is coated and dried for a period of time sufficient to remove a substantial portion of the water, but in most embodiments the surfactant(s) employed will remain in the dried coating whether or not such surfactants are reacted with and become part of the polymer.

Drying of the suspension will, in some embodiments, also result in removal of some portion or a substantial portion of any unreacted volatile monomers. In some embodiments, one or more additional components are added to the suspension polymer including monomer composition including structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CH ₃ , a stabilizer, and optionally one or more additional components, to form the adhesive composition, and the amended suspension is employed to coat one or more supports and dried to remove a substantial portion of the water and some or a substantial portion of any other remaining volatile components. In preferred embodiments, the suspension polymer may have an average particle size 20 pm to 100 pm, optionally 30 pm to 80 pm as measured by conventional means using, for example, a Horiba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan). After drying, it is desirable that the adhesive compositions include no more than 1 wt.%, for example, 0.5 wt.% to 5 ppm, or 500 ppm to 10 ppm, or 100 ppm to 1 ppm, of unreacted monomers, based on the total weight of monomers added to the suspension polymerization reaction vessel.

In certain embodiments, the adhesive coating contains the polymer including structural isomers of a secondary (meth)acrylate of Formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or C¾, and 0.02 wt.% to 33 wt.% of the stabilizer based on the total weight of the polymer plus the stabilizer. In preferred embodiments, the polymer may have an average particle size 20 pm to 300 pm, optionally 30 pm to 100 pm as measured by conventional means using, for example, a Horiba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan). In some embodiments, the adhesive composition contains at least 70 wt.%, or at least 80 wt.%, or at least 85 wt.% polymer, based on the total weight of the polymer plus stabilizer. In some embodiments, the adhesive composition contains up to 98 wt.%, or up to 95 wt.% polymer, based on the total weight of the polymer plus the stabilizer. In some embodiments, the adhesive composition contains at least 0.05 wt.%, at least 1 wt.%, at least 2 wt.%, or at least 5 wt.% stabilizer, based on the total weight of the polymer plus the stabilizer. In some embodiments, the adhesive composition contains up to 30 wt%, up to 25 wt.%, up to 20 wt.%, or up to 15 wt.% stabilizer, based on the total weight of the polymer plus the stabilizer. In some embodiments, the adhesive composition contains 70 wt.% to 98 wt.% polymer plus 2 wt.% to 30 wt.% stabilizer, based on the total weight of the polymer plus the stabilizer. Lor example, the adhesive composition can contain 80 wt.% to 98 wt.% polymer and 2 wt.% to 20 wt.% phenolic resin, or 85 wt.% to 98 wt.% polymer and 2 wt.% to 15 wt.% stabilizer, or 85 wt.% to 95 wt.% polymer and 5 wt.% to 15 wt.% stabilizer.

The polymer in any of the adhesive compositions may contain the following monomeric units:

75 wt.% to 95 wt.%, based on the total weight of monomeric units, of at least three structural isomers of a secondary (meth)acrylate of formula (I): where R ¹ and R ² are each independently H or a Ci to Cio saturated linear alkyl group, the sum of the number of carbons in R ¹ and R ² is 7 to 18, inclusive, and R ³ is H or CH ₃ , and 5 wt-% to 25 wt.%, based on the total weight of monomeric units, of one or more high Tg monomeric units derived from a high Tg monomer having a (meth)acryloyl group and having a Tg at least 25 °C, optionally of at least 30 °C, optionally of at least 50 °C when homopolymerized, or a mixture of two or more thereof.

In some embodiments, adhesive compositions of the present disclosure may further comprise at least one of a binder, a rheology modifier, and a base.

Binders useful in embodiments of the present disclosure may include binders such as those disclosed in U.S. Pub. No. 2003/0109630 (Smith etal.). In some embodiments, the binder may be a resin, a latex, or combinations thereof. Resins suitable for use as a binder in embodiments of the present disclosure may include, for example, relatively hard resins such as epoxies and nitrocellulose and/or relatively soft resins such as acrylates and vinyl ethers. In some embodiments, resins available from Lubrizol Corporation, Wickliffe, OH, USA, under the trade names HYCAR and CARBOTEC (e.g., CARBOTEC 26222) may be employed. Latexes suitable for use as a binder in embodiments of the present disclosure may include, for example, latexes prepared as described in U.S. Pat. No. 4,629,663 (Brown et al .), U.S. Pat. No. 3,857,731 (Merrill et al.) and U.S. Reissue Pat. No. 24,906 or available under the trade name FASTBOND Insulation Adhesive 49 from 3M Company, Saint Paul MN, USA. Commonly the binder is present in the adhesive composition in amounts of 1 wt.% to 40 wt.% , or in some instances 1 wt.% to 20 wt.%, based on the total weight of solids in the adhesive composition.

Rheology modifiers useful in embodiments of the present disclosure may include anionic alkali- soluble associative thickeners, such as, for example rheology modifiers available commercially under the trade names ACRYSOL (e.g., ACRYSOL ASE 60, ACRYSOL TT935) and ACRYSOL HASE from Dow, Collegeville, PA, USA, xanthan gums, such as those available under the trade name KELZAN S from CP Kelco, Atlanta, GA, USA, hydrophobic modified acrylic swellable copolymer emulsions (HASE) and hydrophobically modified ethoxylated urethanes (HEUR) available commercially under the trade name RHEOVIS from BASF SE, Ludwigshafen, Germany, and combinations thereof. Additional suitable rheology modifiers may include polyvinyl alcohol (PVA), clay materials, acid derivatives, acid copolymers, urethane associate thickeners (UAT), polyether urea polyurethanes (PEUPU), polyether polyurethanes (PEPU), or mixtures thereof. Commonly the rheology modifier is present in the adhesive composition in amounts of up to 2 wt.% based on the total weight of solids in the adhesive composition.

Bases useful in embodiments of the present disclosure may assist in adjustment of the thickness of the adhesive composition and may include, for example, aqueous sodium hydroxide and/or aqueous ammonia (e.g., 10% aqueous N¾ OH).

The viscosity and shear stability of the adhesive compositions of the disclosure provide broad flexibility in selecting coating methods for coating the adhesive compositions onto one or more supports to form a masking article. Non-limiting examples of useful coating processes employed in conjunction with the adhesive compositions include knife coating, slot coating, die coating, flood coating, rod coating, curtain coating, spray coating, brush coating, dip coating, kiss coating, gravure coating, die coating, print coating operations such as flexographic, inkjet, or screen print coating, and the like. In some embodiments the adhesive compositions are coated as a continuous coating; in other embodiments they are pattern coated.

Coating of an adhesive composition is followed by drying using a suitable temperature and period of time for drying that is sufficient to remove a substantial portion of the water and any other volatile substances associated with the suspension mixture.

In some embodiments, an adhesive composition of the present disclosure may include a first polymer prepared as described above and a second polymer prepared as described above, where the first polymer may have a first average particle size (e.g., 20 pm to 300 pm) and the second polymer may have a second average particle size (e.g., 30 pm to 100 pm) as measured by conventional means using, for example, a Horiba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan). In some embodiments, the first average particle size and the second average particle size may be different. In some embodiments, the fist polymer and the second polymer may have the same formulation. In some embodiments, the fist polymer and the second polymer may have different formulations.

Adhesive Articles

The adhesive articles of the disclosure include at least an adhesive composition of the disclosure. The adhesive article may or may not include a backing support. If a backing is used, it is an advantage of the disclosure that adhesive articles of the disclosure are easy to make, in many embodiments employing a single pass coating operation to fabricate an adhesive article. In embodiments where the adhesive composition is coated as a suspension, the single coating pass is followed by a drying step. No additional steps are required in order to fabricate an adhesive article of the disclosure.

While the adhesive articles of the disclosure are not particularly limited as to type and shape of the support, in many embodiments the support is a sheet or film suitable for converting to a tape article. The supports may also be provided in roll form. Tape articles are rectangular strips that typically are converted from larger sheets or rolls into the desired width and length. Such conversion is typically carried out after coating the adhesive compositions onto the tape film or sheet. Variables in an adhesive coating process include film or sheet thickness of the support, chemical composition of the support, and nature of the adhesive composition to be coated.

An adhesive article may be employed in any form or shape, including rectilinear, non-rectilinear shapes, and irregular shapes. Backings employed in forming adhesive articles of the disclosure are typically 12 micrometers to 3 centimeters (cm) thick. The backing can be made of any desired material. Representative examples of materials suitable for the backing can include, for example, polyolefins, such as polyethylene, including high density polyethylene, low density polyethylene, linear low density polyethylene, and linear ultralow density polyethylene, polypropylene, and polybutylenes; vinyl copolymers, such as polyvinyl chlorides, both plasticized and unplasticized, and polyvinyl acetates; olefinic copolymers, such as ethylene/methacrylate copolymers, ethylene/vinyl acetate copolymers, acrylonitrile-butadienestyrene copolymers, and ethylene/propylene copolymers; acrylic polymers and copolymers; polyurethanes; and combinations of the foregoing. Mixtures or blends of any plastic or plastic and elastomeric materials such as polypropylene/polyethylene, polyurethane/polyolefin, polyurethane/polycarbonate, polyurethane/polyester, can also be used.

In some embodiments, the backing is or includes a composite foam that includes a flexible polymeric foam layer, a first film laminated to a first major surface of the foam layer, and a second film laminated to a second, opposite major surface of the foam layer. Adhesive(s) can be attached to the films to form a structure of adhesive-film-foam-film-adhesive. The flexible polymeric foam layer can be chosen to optimize conformability and resiliency properties which are helpful when the mounting assembly is to be adhered to surfaces having surface irregularities. Such is the case with atypical wall surface. An exemplary flexible polymeric foam layer is commercially available under the trade designation “Command” from Minnesota Mining and Manufacturing Company (“3M”) of St. Paul, Minn. In some embodiments, the flexible polymeric foam layer of the flexible backing layer can include polyolefin foams which are available under the trade designations “Volextra” and “Volara” from Voltek, Division of Sekisui America Corporation, Lawrence, Mass. In some embodiments, the backing is metal or metal-like. In some embodiments, the backing is wood or wood-like.

The backing can be or include any of the materials or backings described in any of the following: US Pat. No. 9,920,783 (Runge et al.) and International Publication Nos. WG/2018/183195 (Lehmann et ak), and W02019/040862 (Krull et al.) In particular embodiments, the backing can include the multilayer films featuring a core and one or more skin layers as described in PCT Application No. US2017/016039 (Runge et al.). In various embodiments, the backing can be fabricated or produced from microstructured tape materials described in, e.g., U.S. Pat. No. 8,530,021 to Bartusiak et al.

In other embodiments, the backing can include a nonwoven substrate. The nonwoven substrate can be a nonwoven fabric or web manufactured by any of the commonly known processes for producing nonwoven fabric or webs. As used herein, the term “nonwoven” refers to a fabric that has a structure of individual fibers or filaments which are randomly and/or unidirectionally interlaid in a mat-like fashion, but not in an identifiable manner as in a knitted fabric. Nonwoven fabrics or webs can be formed from various processes such as meltblowing processes, spunbonding processes, spunlacing processes, and bonded carded web processes, air laying processes, and wet laying processes. In some embodiments, the core comprises multiple layers of nonwoven materials with, for example, at least one layer of a meltblown nonwoven and at least one layer of a spunbonded nonwoven, or any other suitable combination of nonwoven materials. For example, the backing may be a spunbond-meltbond-spunbond, spunbond- spunbond, or spunbond- spunbond-spunbond multilayer material. Or, the backing may be a composite web comprising a nonwoven layer and a film layer. Features and aspects of nonwovens backings are described in International Publication No. W02019040820 (Krull et al.).

The backing can be a single layer or a multi-layer construction. In some embodiments, two or more sub-layers can be co-extruded so as to form the backing. In some embodiments, the backing is flexible.

Some embodiments include dyes or pigments in the backing layer. Some embodiments include at least one tackifier in at least one layer of the backing. Some embodiments include a plasticizing oil in one or more layers of the backing.

The backing can be any desired shape including, for example, square, rectangle, triangular, polygon, circular, quadrilateral, trapezoidal, cylindrical, half-circular, star-shaped, half-moon shaped, tetrahedral, combinations thereof, etc. In some embodiments, the backing has a size of between about 70 mm2 and about 10,000,000 mm2. In some embodiments, the backing has a size of between about 100 mm2 and about 5,000 mm2.

In some embodiments, the backing has a Young’s modulus of between about 100 psi and about 100,000 psi. In some embodiments, the backing exhibits an elastic recovery of 1-100% at 10% strain as measured by ASTM D5459-95. In some embodiments, the backing exhibits an elastic recovery of 1- 100% at 20% strain.

In some embodiments, the backing has a modulus of elasticity and/or a modulus of secant of between about 100 psi and about 15,000 psi as determined by at least one of ASTM D638-14 and ASTM D412-06a. In some embodiments, the backing has a modulus ranging between 100 psi and 15000 psi. In some embodiments, the modulus is greater than 100 psi, greater than 500 psi, greater than 1000 psi. In some embodiments, the backing modulus is less than 15000 psi, less than 10000 psi, less than 8,000 psi, less than 5,000 psi, less than 3,500 psi, less than 2000 psi, and less than 1500 psi.

In some embodiments, the backing and/or at least some of the backing layers are substantially optically clear. As used herein, the term “optically clear” means having a light transmission of at least about 50% and/or a haze of no greater than 40%. Some embodiments have a light transmission of at least about 75%. Some embodiments have a haze of no greater than 20%. Both the light transmission and the haze of the backing can be determined using, for example, ASTM D 1003 -95.

In some embodiments, the backing has a thickness of between about 0.1 mils and about 100 mils. In some embodiments, the backing has a thickness of greater than 1 mil, greater than 5 mils, greater than 8 mils, greater than 10 mils, greater than 12 mils, greater than 15 mils, greater than 20 mils, greater than 22 mils, or greater than 24 mils. In some embodiments, the backing has a thickness of less than 100 mils, less than 90 mils, less than 80 mils, less than 75 mils, less than 70 mils, less than 65 mils, less than 60 mils, less than 55 mils, less than 50 mils, less than 45 mils, less than 40 mils, less than 38 mils, less than 35 mils, less than 32 mils, less than 30 mils, less than 28 mils, or less than 25 mils.

The backing can include a non-tacky tab, which can be grasped and pulled by a user to stretch and/or peel the article during the removal process, so as to remove the tape from the object or substrate to which it has been affixed. The non-tacky tab can be an extension of the backing material or a detackified portion of an adhesive. The non-tacky tab can be formed from a tacky adhesive substrate using any known method of producing a non-tacky area including, e.g., applying a deadening material or process to the adhesive to render it non-tacky. Where present, the tab can be of any shape or size. The tab can be made of the same material as the backing or of a different material. In some embodiments, the tab has an area that is between about 5% and about 25% of the total area of the adhesive mounting assembly. In some embodiments, there is no obvious tab and the mounting device or hook act as the tab

The adhesive mounting articles can further include a release liner adjacent to any exposed adhesive region(s). The release liner protects the adhesive during manufacturing, transit, and before use. When the user desires to use the adhesive assembly, the user can peel or remove the release liner to expose the adhesive. Examples of suitable liners include paper, e.g., kraft paper, or polymeric films, e.g., polyethylene, polypropylene or polyester. At least one surface of the liner can be treated with a release agent such as silicone, a fluorochemical, or other low surface energy based release material to provide a release liner. Preferred release liners are fluoroalkyl silicone or silicone polycoated paper. The release liner can be printed with lines, brand indicia, or other information. In some embodiments, the backing is embossed or micro-embossed; embossed or micro- embossed supports include any of the backing materials and constructions described above. In some such embodiments, embossed or micro-embossed features are disposed on the major side of the backing contacting the adhesive composition. In other embodiments, the embossed or micro-embossed features are disposed on the major side of the backing opposite to the side coated with the adhesive composition. In still other embodiments, embossed or micro-embossed features are disposed on both major sides of the backing; the features disposed on the two major sides are the same or different in various embodiments.

In some embodiments, the adhesive composition itself includes embossed features, either by virtue of being coated on an embossed surface, or by disposing an adhesive composition between the backing and an embossed release liner.

Embossed features imparted to the adhesive compositions themselves are useful, for example, to impart at least a degree of repositionability to the adhesive articles of the disclosure or allow for air bleed from between the adhesive article and the masked surface. Embossing and micro-embossing are accomplished using techniques known to the skilled artisan and include nip roll embossing using a patterned nip roll, and profde extrusion; secondary processes such as tentering and slicing are further employed in some embodiments to modify surface structures imparted by the embossing or micro embossing process. Particularly suitable embossed backings are described in International Publication No. W02019040820 (Krull et ak).

The width and length of the adhesive articles of the disclosure are not particularly limited. Additionally, in some embodiments, the adhesive articles of the disclosure are suitably converted to smaller sheets or rolls, for example, 20 cm by 28 cm sheets, for use by a consumer. In some embodiments, sheets or rolls are provided to a consumer who is then free to divide the sheet or roll into the desired shape and dimensions for use in a specific application.

The shapes easily utilized in conjunction with the backing onto which the adhesive compositions of the disclosure are coated are virtually unlimited in terms of ease of manufacturing and even ease of the end user in converting one supplied shape to a customized shape, for example, by hand cutting with scissors, a box cutter, a hole punch, a die cutter, or any other cutting implement. Thus, for example, a consumer could buy a 20 cm by 28 cm sheet of a mounting article of the disclosure and cut it into the desired shape for a specific end use.

In some embodiments, prior to coating and drying the adhesive compositions of the disclosure on the backing, the backing is pre-treated. Pre-treatments are applied to, or carried out on, the major surface of the backing onto which the adhesive composition will be coated, when an increase in the adhesive bonding between the backing and the adhesive composition is necessary to prevent failure of the backing- adhesive interface when a mounting article or other adhesive article is removed from the surface onto which it was applied in use.

Pre -treatments include coatings applied to the backing surface. One of skill will understand that the nature of such "primer" coatings is specific to each backing and specific adhesive composition, and a wide variety of such primer coatings are available— in fact, some backing materials are available pre- primed for this purpose. Another type of suitable pre-treatment is roughening the surface of the backing prior to coating, which increase surface area for adhesion by the coated adhesive compositions of the disclosure. Yet another type of suitable pre-treatment is corona or plasma treatment of the surface to induce chemical changes that can increase adhesion of the adhesive compositions of the disclosure to the backing. While such pre-treatments are useful in some embodiments, in other embodiments many suitable backings including paper, polyethylene terephthalate, polyvinyl chloride, and polycarbonate, are coated with the compositions in the absence of any type of pre-treatment to improve bonding at the backing- adhesive interface.

In some embodiments, where the adhesive article is a tape, the major side opposite the side of the backing onto which the adhesive composition will be coated is treated in order to facilitate release of the adhesive from the major side opposite to the adhesive-coated side during unwinding of the tape by the end user. Such coatings, often termed "low adhesion backside" or LAB in the industry, are well known by those of skill and any of the conventionally employed LAB treatments and coatings are suitably applied to the tape supports employed to form the masking tape articles of the disclosure. Conventional LAB treatments are suitably employed in various embodiments of the disclosure to provide tape articles having conventional values of unwind force, for example, of 50 grams per centimeter (g/cm) to 500 g/cm, or 100 g/cm to 350 g/cm, when measured at 180° peel at a rate of 228.6 cm/min and set time of 5 seconds.

In some embodiments, the adhesive article includes a release liner. For example, in some embodiments, it is desirable to form the adhesive article in sheet form, or it is useful for some other reason to avoid having the adhesive article wound upon itself as is commonly done with adhesive tapes. For example, if the end use is a stenciling application, it is generally desirable to employ a release liner— that is, a separate support-type sheet or film— applied to the coated and dried adhesive composition residing on the support. In such embodiments, the backing is coated on one major side thereof with the adhesive composition, the adhesive composition is dried if necessary, and a release liner is applied on top of the dried adhesive layer. The release liner is formed from, or coated with, a material that releases cleanly from the adhesive when peeled off by the end user, in embodiments transferring substantially no residue of the release liner material on or in the adhesive. Such release liners are well known by those of skill and any of the conventionally employed release liners are suitably applied to the tape supports employed to form the masking tape articles of the disclosure.

Alternatively, an adhesive composition of the present disclosure can be coated or otherwise formed directly on a release liner. The adhesive coated release liner can be used to transfer to the adhesive onto a backing. In certain embodiments, the release liner is provided to cover and protect the external surface of adhesive after being laminated to the backing, such that when the release liner is peeled from the adhesive, the adhesive remains with the backing. In other embodiments, a separate release liner may be temporarily fixed to the adhesive coated backing. In some embodiments, the adhesive compositions of the disclosure are coated onto the selected support at coating weights of 5 grams per square meter (g/m ² ) to 90 g/m ² , or 10 g/m ² to 70 g/m ² , or 15 g/m ² to 50 g/m ² , of the dried adhesive composition on the support. However, it will be understood that the adhesive articles of the disclosure are not limited to mounting applications, and for various applications a thicker or thinner coating of the adhesive is useful and is easily optimized by one of skill.

In some embodiments, a method of making an adhesive article including adhesive compositions of the present disclosure may include the steps of: 1) forming an aqueous polymerizable pre-adhesive reaction mixture according to the above disclosure; 2) polymerizing the monomers in the pre-adhesive reaction mixture to form a polymerized mixture, where the average particle size of polymers in the polymerized mixture is 20 pm to 300 pm, optionally 30 pm to 100 pm; 3) coating the polymerized mixture onto a support to form a coated mixture; and 4) drying the coated mixture.

In some embodiments, and as described above, adhesive compositions of the present disclosure may further comprise at least one of a binder, a rheology modifier, and a base. Therefore, in some embodiments, the method of making an adhesive article including adhesive compositions of the present disclosure may further include the step of adding at least one of the binder, the rheology modifier, and the base to the polymerized mixture, i.e., after step 2 is completed, a process that may be referred to as “compounding.”

Applications of the Adhesive Articles

In various embodiments, the adhesive articles of the disclosure are applied to a selected substrate, whereupon the adhesive composition performs as a pressure-sensitive adhesive. Pressure-sensitive adhesives are recognized as a standard class of materials. Pressure-sensitive adhesives are generally recognized as having tack at temperatures ranging from 15 °C to 25 °C and adhesion to a variety of dissimilar surfaces upon mere contact without the need for more than manual pressure. Pressure-sensitive adhesives require no activation by water, solvent, or heat in order to exert a strong adhesive holding force towards materials such as paper, cellophane, glass, plastic, wood, and metal. Pressure-sensitive adhesives have a sufficiently cohesive holding and elastic nature that, despite their aggressive tackiness, they can be handled with the fingers and removed from smooth surfaces without leaving a substantial residue (see. e.g., Test Methods for Pressure sensitive Tapes, 6th Ed., Pressure Sensitive Tape Council, 1953). Pressure sensitive adhesives and tapes are well known, and the wide range and balance of properties desired in such adhesives has been well analyzed (see, e.g., U.S. Pat. No. 4,374,883 (Winslow etal.); and "Pressure sensitive Adhesives" in Treatise on Adhesion and Adhesives Vol. 2, "Materials," R.I. Patrick, Ed., Marcel Dekker, Inc., N.Y., 1969).

Substrates on which the adhesive compositions of the disclosure have good performance as a pressure-sensitive adhesive, include, but are not limited to, paper, glass, metal, wood (including wood products such as cardboard or particleboard), drywall, synthetic or natural polymers including filled, colored, crosslinked or surface -modified polymers including, for example, polyvinyl chloride, polyesters such as polyethylene terephthalate or polylactic acid, natural or synthetic rubber, polyamides, polyolefins such as polyethylene or polypropylene, appliance or equipment casing materials such as acrylonitrile- butadiene-styrene (“ABS”) copolymers, polycarbonate, polymethyl methacrylate, and the like; and mixed or composite materials such as polymer-wood composites, and the like, and any painted and/or primed surface thereof. In some embodiments, the surface is painted with a low or no volatile organic compound (VOC) paint.

In particular, the adhesive articles can be removed from fibrous articles such paper, construction paper, and paper board with minimal or no damage.

Some adhesive articles of the present disclosure have excellent shear strength. Some embodiments of the present disclosure have a shear strength of greater than 1600 minutes as measured according to ASTM D3654. Some embodiments of the present disclosure have shear strength of greater than 10,000 minutes as measured according to ASTM D3654. Some other embodiments of the present disclosure have shear strength of greater than 100,000 minutes as measured according to ASTM D3654- 82.

Some adhesive articles of the present disclosure have an elongation at break of greater than 50% in at least one direction. Some adhesive articles of the present disclosure have an elongation at break of between about 50% and about 1200% in at least one direction.

Some adhesive articles of the present disclosure have a tensile strength at break sufficiently high so that the adhesive article will not rupture prior to being removed from an adherend at an angle of 35° or greater.

In some embodiments, the adhesive articles of the present disclosure exhibit enhanced conformability to a substrate or surface than prior art adhesive mounting articles. In some embodiments, the adhesive articles of the present disclosure hold more weight when adhered or attached to a substrate or surface than prior art adhesive mounting articles. In some embodiments, the adhesive articles of the present disclosure hold more weight for a longer period of time when adhered or attached to a substrate or surface than prior art adhesive mounting articles. In some embodiments, the adhesive articles of the present disclosure remain adhered to a textured, rough, or irregular surface for a longer period of time than prior art adhesive mounting articles. In some embodiments, the adhesive articles of the present disclosure hold a higher amount of weight when adhered to a textured, rough, or irregular surface than prior art adhesive mounting articles.

The adhesive articles may be used to mount various items and objects to surfaces such as painted drywall, plaster, concrete, glass, ceramic, fiberglass, metal or plastic. Items that can be mounted include, but are not limited to, wall hangings, organizers, holders, baskets, containers, decorations (e.g., holiday decorations), calendars, posters, dispensers, wire clips, body side molding on vehicles, carrying handles, signage applications such as road signs, vehicle markings, transportation markings, and reflective sheeting. The adhesive articles may be used to mount items and materials, such as anti-slip mats or anti fatigue mats, to a floor surface or the bottom of a tub or shower, or to secure items, such as area rugs, to a floor. The adhesive article can be used in various joining and assembling applications including such as adhering at least two containers (e.g. , boxes) for later separation. The adhesive article can be used in various cushioning and sound deadening applications such as, for example, cushioning materials for placement beneath objects, sound insulating sheet materials, vibration dampening, and combinations thereof. The adhesive article can be used in various closure applications including container closures (e.g., box closures, closures for food containers, and closures for beverage containers), diaper closures, and surgical drape closures. The adhesive article can be used in various thermal insulation applications. The adhesive article can be used in various sealing applications such as in gaskets for liquids, vapors (e.g., moisture), and dust. The adhesive article can be used in various labels such as removable labels (e.g., notes, price tags, and identification labels on containers), and in signage. The adhesive article can be used in various medical applications (e.g., bandages, wound care, and medical device labeling such as in a hospital setting). The adhesive article can be used in various fastening applications such as fastening one object (e.g., a vase or other fragile object) to another object (e.g., a table or a book shelf). The adhesive article can be used in various securing applications such as fastening one or more components of a locking mechanism to a substrate (e.g., a child safety lock can be adhered to a cabinet or cupboard).

The adhesive article can be used in various tamper indicating applications (e.g., tamper indicating articles). The adhesive article can also be incorporated in a variety of other constructions including, but not limited to, abrasive articles (e.g., for sanding), articles for sanding and polishing applications (e.g., buffing pads, disc pads, hand pads, and polishing pads), pavement marking articles, carpeting (e.g., backing for carpeting), and electronic devices (e.g., securing a battery within a housing in a cell phone or PDA (personal digital assistant) to prevent unwanted movement).

The adhesive article (i.e., those in adhesive tapes or single article) can be provided in any useful form including, e.g., 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). Likewise, multiple adhesive articles can be provided in any suitable form including, e.g., tape, strip, sheet (e.g., perforated sheet), label, roll, web, disc, kit, stack, tablet, and combinations thereof in any suitable package including, for example, dispenser, bag, box, and carton. The adhesive articles are particularly well suited to being provided in roll form, as the size of the active adhesive areas can be essentially unlimited.

Adhesive articles can also be initially repositionable and may even be reusable in some core iterations until one of the adhesive layers loses tack. As used herein, "repositionable" means an adhesive article that can be applied to a substrate and then removed and reapplied without distorting, defacing, or destroying the adhesive article, or substrate.

Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure. ° = degree, in. = inch, lb. = pound, min. = minute, g = grams, °C = degrees Celsius, RH = relative humidity, mL = milliliters, % percentage, L = liter, rpm = revolutions per minute.

EXAMPLES

Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight.

Table 1. Materials Test Methods

Particle Size Measurements

Microsphere particle-size measurements were performed using aHoriba LA 910 particle size analyzer (Horiba, Ltd, Kyoto, Japan).

Painted Drvwall Preparation

A 3/8 in. standard drywall was painted with primer using a 3/8 in. nap roller. The primer was allowed to dry for at least a day. Two coats of Valspar Ultra 2K paint, allowing the paint to dry to the touch between coats. The painted drywall was allowed to dry at ambient conditions for at least seven days prior to testing.

Drvwall Damage Testing

Damage testing was conducted by applying example mounting squares to painted drywall board. Samples were dwelled under ambient conditions for 5 days. Samples were removed by hand at an appropriate angle at a peel rate of at least 90 in./min. Damage was assessed using a scoring system where 0 indicates no damage, 1 indicates minimal damage (<10% of the covered area), 2 indicates large amounts of damage (10-50% of the covered area), and 3 indicates major damage (>50% of the covered area).

Construction Paper Damage Testing

Damage testing was conducted by applying example mounting squares to construction paper. Samples were rolled with a 15 lb. roller (12 passes). Samples were dwelled under ambient conditions for 5 days under ambient conditions. Samples were removed by hand at an appropriate angle at a peel rate of at about 90 in./min. Damage was assessed using a scoring system where 0 indicates no damage, 1 indicates minimal damage (<10% of the covered area), 2 indicates large amounts of damage (10-50% of the covered area), and 3 indicates major damage (>50% of the covered area).

Poster Hanging Test

Posters containing high curl were mounted to drywall board painted with Behr PPU FEN. Posters were mounted with four ¾” mounting squares (1 in each comer). After 1 month of hanging, the mounting squares were rated as pass/fail. A “pass” score was given if no failure modes were observed. Any failure mode for the poster was rated as a “fail”.

Example 1: Preparation of Microsphere Adhesives (“MSAs”) A1 - A2 A 500 mL resin flask (4" diameter) was charged with STEPANOL AMV, HITENOL BC 1025, and water in amounts as shown in Table 2 to provide an aqueous phase. In a separate flask, an oil phase was prepared by mixing C12 Acrylates, IBOA, MAA, tOACM, and VAZO 52 in amounts as shown in Table 2. After complete mixing with a TEFLON-coated magnetic stir bar, the oil phase was added to the aqueous phase all at once. An overhead stirrer equipped with a glass trailing edge stir rod was used to mix the phases at a rate as disclosed in Table 3. During the agitation, the multi-phase mixture was degassed by sparging with nitrogen for 30 minutes. After degassing, the mixture was heated to 60 °C. The peak temperature during the exotherm typically reached as high as 75 °C. The mixture was allowed to cool to 60 °C and was then maintained at that temperature for 8 hours. The mixture was cooled to room temperature and compounded as described in Example 2.

Table 2. Pre-adhesive Mixtures

Table 3. Microsphere Particle Sizes

Example 2: Preparation of Compounded Formulations F1-F2

The heterogeneous MSA adhesive mixtures A1-A2 were agitated to disperse the particles immediately before use. Agitated MSA adhesive mixture was added to a 1000 mL HDPE bottle. To the MSA adhesive mixture a binder latex (-50% solids in water) was added, followed by the addition of ACRYSOL ASE-60. The solution was mixed on ajar roller for about 5 minutes followed by the addition of aqueous ammonia (1 mL, 10% in water). The solutions were rolled on ajar roller at 10-30 rpm at room temperature for at least 12 hours before coating. Compounded formulations are shown in Table 4. Table 4. Compounded Formulations

Example 3: Preparation of Mounting Square Examples E1-E2

Adhesive formulations were knife coated (4 mil wet gap) onto release liner and passed through an oven to dry for 15 minutes at 70 °C. The release liner was laminated to a primed film-foam-film construction on both sides. Mounting squares were punched out into 0.75 x 0.75 in squares using a hydraulic press. Examples constructions with various coat weights are shown in Table 5 and a performance summary is shown in Table 6. Table 5. Example Mounting Squares

Table 6. Example performance All cited references, patents, and patent applications in the above application for letters patent are herein incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control. The preceding description, given in order to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto.