Stabilized copolymers, adhesive compositions, methods of making adhesive compositions, and articles including adhesive compositions

Abstract

An adhesive composition comprising an acrylic copolymer having a pendant organosiloxane group, a pendant polyether group, and optionally an acidic group. An article includes a substrate having the adhesive composition attached thereto. A method of preparing the adhesive composition is also disclosed. Certain acrylic copolymers are disclosed.

Description

Background Art

[0001] Surfactants are widely used in industry. Foam-based articles, such as, for example, foam tapes, are widely used in domestic and commercial applications. During manufacture, various additives may be used to stabilize polymerizable foams prior to their polymerization. Summary of the invention

[0002] Advantageously, the stabilizing copolymers according to the present disclosure can be used as surfactants for stabilizing foams in adhesive compositions and can be equal to or superior to other surfactants known for use in applications.

[0003] In one aspect, the present disclosure provides an adhesive composition, comprising a polymeric composition comprising the following components:

[0004] i) at least one stabilizing copolymer, the at least one stabilizing copolymer comprising:

[0005] a) 20 to 90 wt% of at least one first divalent monomer unit, the at least one first divalent monomer unit being represented by the formula:

[0006]

[0007] in:

[0008] Each R 1 are independently H or methyl;

[0009] Each R 2 are independently methyl or ethyl;

[0010] Each R 3 are independently methylene, ethenyl or propenyl;

[0011] Each R 4 are independently methyl, ethyl, propyl or butyl;

[0012] Each n is independently an integer from 2 to 65; and

[0013] b) 10 to 80 wt% of at least one second divalent monomer unit, the at least one second divalent monomer unit being represented by the formula:

[0014]

[0015] in:

[0016] Each R 6 independently represents a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group; and

[0017] Each X independently represents H or an alkyl group having 1 to 6 carbon atoms; and

[0018] at least one first cross-linking agent;

[0019] ii) at least one alkyl (meth)acrylate, the at least one alkyl (meth)acrylate having 7 to 24 carbon atoms;

[0020] iii) at least one optional polar free radical polymerizable monomer; and

[0021] iv) at least one second cross-linking agent.

[0022] In another aspect, the present invention provides an article comprising:

[0023] substrate; and

[0024] An adhesive composition attached to a substrate according to the present disclosure.

[0025] In another aspect, the present disclosure provides a method for preparing an adhesive composition, the method comprising the following sequential steps:

[0026] I) providing a first polymerizable composition, the first polymerizable composition comprising:

[0027] at least one alkyl (meth)acrylate;

[0028] at least one optional first polar free radical polymerizable monomer; and

[0029] at least one first free radical polymerization initiator;

[0030] II) forming a syrup composition by partially polymerizing the first polymerizable composition, wherein the syrup composition comprises:

[0031] 1 wt % to 20 wt % of a solute polymer, based on the total weight of the slurry composition, the solute polymer having a weight average molecular weight of at least 100,000 Daltons; and

[0032] 80 wt % to 99 wt % of a solvent monomer, based on the total weight of the syrup composition, the solvent monomer comprising:

[0033] the at least one alkyl (meth)acrylate; and

[0034] the at least one optional first polar free radical polymerizable monomer; and

[0035] III) preparing a second polymerizable composition comprising:

[0036] slurry composition;

[0037] at least one optional second polar free radical polymerizable monomer, wherein the at least one optional second polar free radical polymerizable monomer and the at least one optional first polar free radical polymerizable monomer may be the same or different;

[0038] At least one stabilizing copolymer comprising:

[0039] a) 20 to 90 wt% of at least one first divalent monomer unit, the at least one first divalent monomer unit being represented by the formula:

[0040]

[0041] in:

[0042] Each R 1 are independently H or methyl;

[0043] Each R 2 are independently methyl or ethyl;

[0044] Each R 3 are independently methylene, ethenyl or propenyl;

[0045] Each R 4 are independently methyl, ethyl, propyl or butyl;

[0046] Each n is independently an integer from 2 to 65; and

[0047] b) 10 to 80 wt% of at least one second divalent monomer unit, the at least one second divalent monomer unit being represented by the formula:

[0048]

[0049] in:

[0050] Each R 6 independently represents a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group; and

[0051] Each X independently represents H or an alkyl group having 1 to 6 carbon atoms;

[0052] at least one cross-linking agent;

[0053] at least one second free radical initiator;

[0054] IV) foaming the second polymerizable composition to provide a foamed polymerizable composition; and

[0055] V) polymerizing the foamed polymerizable composition to form the adhesive composition.

[0056] In another aspect, the present disclosure provides a stabilized copolymer comprising:

[0057] a) 20 wt% to 90 wt% of at least one first divalent monomer unit represented by the formula:

[0058]

[0059] Wherein:

[0060] Each R 1 is independently H or methyl;

[0061] Each R 3 is independently methylene, vinyl or propenyl;

[0062] Each R 4 is independently methyl, ethyl, propyl or butyl;

[0063] Each n is independently an integer from 2 to 65; and

[0064] b) 10 wt% to 80 wt% of at least one second divalent monomer unit represented by the formula:

[0065]

[0066] Wherein:

[0067] Each R 6 independently represents a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group contains an ethoxyethyleneoxy group; and

[0068] Each X independently represents H or an alkyl group having 1 to 6 carbon atoms.

[0069] Unless otherwise indicated, all numerical ranges in the specification and claims include their end values.

[0070] As used herein:

[0071] The terms "acryloyloxy" and "acryloxy" are equivalent;

[0072] The term "ethoxyethyleneoxy" refers to the divalent group -CH 2 CH 2 O-;

[0073] The term "isopropylideneoxy" refers to the divalent group And

[0074] The term "(meth)acryloyl" refers to "acryloyl" and / or "methacryloyl".

[0075]

[0026] A further understanding of the features and advantages of the present disclosure will be achieved upon consideration of the detailed description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 is a schematic side view of an exemplary article 100 according to the present disclosure.

[0077] It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that fall within the scope and spirit of the principles of this disclosure.The drawings may not be drawn to scale. DETAILED DESCRIPTION

[0078] Stable copolymer

[0079] Useful stabilizing copolymers for stabilizing foamed acrylic foam adhesive precursors may include: 20 wt% to 90 wt% of at least one first divalent monomer unit a), based on the total weight of the stabilizing copolymer, the at least one first divalent monomer unit being represented by the formula:

[0080]

[0081] and 10 to 80 wt % of at least one second divalent monomer unit b), based on the total weight of the stable copolymer, the at least one second divalent monomer unit being represented by the formula:

[0082]

[0083] These generally correspond to the corresponding acrylic monomers used to synthesize stable copolymers (eg, by free radical copolymerization using techniques known in the art).

[0084] Each R 1 are independently H or methyl.

[0085] Each R 2 are independently methyl or ethyl.

[0086] Each R 3 are independently methylene (i.e., -CH 2 -), vinyl (i.e. -CH 2 CH 2 -), or propenyl (i.e. -CH 2 CH 2 CH 2 -).

[0087] Each R 4 are independently methyl, ethyl, propyl or butyl. In some preferred embodiments, R 4 It is methyl or propyl.

[0088] Each n is independently an integer from 2 to 65. In some embodiments, n is independently an integer from 10 to 65. In some embodiments, n is independently an integer from 20 to 65. In some embodiments, n is independently an integer from 30 to 65. In some embodiments, n is independently an integer from 40 to 65. In some embodiments, n is independently an integer from 2 to 50. In some embodiments, n is independently an integer from 5 to 50. In some embodiments, n is independently an integer from 10 to 50. In some embodiments, n is independently an integer from 20 to 50. In some embodiments, n is independently an integer from 15 to 45. In some embodiments, n is independently an integer from 25 to 45. In typical embodiments, monomer units with different n values ​​may be present, however this is not required.

[0089] Each R 6 R independently represents a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group and optionally other alkyleneoxy groups. In many embodiments, the poly(alkyleneoxy) group is selected from poly(ethyleneoxy), poly(isopropyleneoxy), poly(propyleneoxy), and poly(butyleneoxy). In some embodiments, the poly(alkyleneoxy) group consists of an ethyleneoxy group. In some embodiments, the poly(alkyleneoxy) group consists of an ethyleneoxy group and an isopropyleneoxy group. In some, R 6 A triblock segment comprising the formula -poly(isopropyleneoxy)-poly(ethyleneoxy)-poly(isopropyleneoxy)-.

[0090] In some embodiments, R 6 It can be expressed by the following formula:

[0091]

[0092] wherein x is an integer greater than or equal to 3, and y and z are integers greater than or equal to 0. In many embodiments, x, y, and z are independently greater than or equal to 6, 8, 10, 12, or 15. In many embodiments, x, y, and z are independently greater than or equal to 25, 20, or 15.

[0093] Each X independently represents H or an alkyl group having 1 to 6 carbon atoms (eg, methyl, ethyl, propyl, butyl, pentyl, hexyl).

[0094] Monomers suitable for producing monomer units a) by polymerization can be synthesized, for example, by known methods and / or can be obtained from commercial sources. Examples of commercially available monomers suitable for producing monomer units a) include 3-[tris(trimethylsiloxy)silyl]propyl methacrylate (available from Sigma-Aldrich, St. Louis, Missouri, USA); 3-[tris(trimethylsiloxy)silyl]propyl acrylate (available from Career Henan Chemical Co., Ltd., Zhengzhou, China); Company, Zhengzhou, China); monomethacryloxypropyl terminated polydimethylsiloxane MCR-M17 (1000 g / mol, available from Gelest, Inc., Morrisville, Pennsylvania); monomethacrylate terminated poly(dimethylsiloxane) (available from Sigma-Aldrich as catalog number 798274); X-22-2404 medium chain, single-terminated methacrylate-modified silicone resin (400 g / mol side chain, available from Shin-Etsu Chemical Co., Ltd., Tokyo, Japan); Co., Tokyo, Japan); X-22-174ASX medium-chain, single-end methacrylate-modified silicone resin (900 g / mol side chain, available from Shin-Etsu Chemical Co., Ltd.); X-22-174BX medium-chain, single-end methacrylate-modified silicone resin (2300 g / mol side chain, available from Shin-Etsu Silicones of America, Akron, Ohio); and KF-2012 medium-chain, single-end methacrylate-modified silicone resin (4600 g / mol side chain, available from Shin-Etsu Chemical Co., Ltd.).

[0095] Based on the total weight of the stable copolymer, the amount of monomer unit a) can be, for example, 20 wt % to 90 wt %, 30 wt % to 85 wt %, 30 wt % to 65 wt %, or 55 to 65 wt %. In some embodiments, based on the total weight of the stable copolymer, the amount of monomer unit a) can be, for example, 20 wt % to 45 wt % or 20 wt % to 30 wt %.

[0096] Monomers suitable for producing monomer units b) can be prepared, for example, by known methods, such as by condensation of (meth)acryloyl chloride or equivalent with a polyether monool or poly(propylene oxide-co-ethylene oxide) monool, or can be obtained from commercial sources. Examples of commercially available monomers suitable for producing monomer units b) include: SR550 methoxypolyethylene glycol (350) monomethacrylate, SR551 methoxypolyethylene glycol (350) monoacrylate, SR552 methoxypolyethylene glycol (550) monomethacrylate, SR553 methoxypolyethylene glycol (550) monoacrylate, SR553 methoxypolyethylene glycol (550) monoacrylate, all of which are available from Sartomer Americas, Exton, Pennsylvania; poly(ethylene glycol) methyl ether acrylate (Catalog No. 454990, M n =480 g / mol) and (polyethylene glycol) methyl ether acrylate (Catalog No. 730829, M n =5000 g / mol), both of which were purchased from Sigma-Aldrich; MPEG 550 methoxy polyethylene glycol monoacrylate, which was purchased from Kowa American Corp., New York, New York, USA; methoxy polyethylene acrylate MW 1000 and methoxy polyethylene acrylate MW 2000, both of which were purchased from SimSon Pharma Limited, Mumbai, India; poly(propylene glycol) methyl ether acrylate (Catalog No. 410187, M n =260 g / mol) and poly(propylene glycol) methyl ether acrylate (Cat. No. 408352, M n =375 g / mol) and poly(propylene glycol) methyl ether acrylate (Cat. No. 454990, M n =480 g / mol), all of which are available from Sigma-Aldrich. One useful monomer is Carbowax methoxypolyethylene glycol 750 acrylate.

[0097] Based on the total weight of the stable copolymer, the amount of monomer unit b) can be, for example, 10 wt % to 80 wt %, 15 wt % to 70 wt %, 35 wt % to 70 wt %, 35 wt % to 65 wt %, or 35 wt % to 45 wt %. In some embodiments, based on the total weight of the stable copolymer, the amount of monomer unit b) can be, for example, 55 wt % to 80 wt % or 70 wt % to 80 wt %.

[0098] In some embodiments, the stable copolymer according to the present disclosure further comprises greater than 0 wt % to 22 wt %, 0.1 wt % to 22 wt %, 1 wt % to 20 wt %, 2 wt % to 20 wt %, 5 wt % to 20 wt %, or 5 wt % to 15 wt % of at least one divalent acidic (meth) acrylic monomer unit, based on the total weight of the stable copolymer. Examples of such divalent monomer units include

[0099]

[0100] Where R 2 As defined above. Exemplary commercially available monomers that can produce divalent acidic (meth) acrylic monomer units include (meth) acrylic acid, β-carboxyethyl acrylate, 2-sulfoethyl methacrylate, N-2-sulfoethyl methacrylamide, 2-hydroxyethyl (meth) acrylate phosphate, 2-phosphoethyl methacrylate. Many others are contemplated and commercially available or prepared according to known methods.

[0101] The stable copolymers according to the present disclosure can be prepared, for example, by free radical polymerization using known techniques. For example, free radical polymerizable monomers (usually in water and / or an organic solvent) can be combined with a thermally activated free radical initiator (e.g., a peroxide or an azo compound) and then heated under an inert atmosphere. Alternatively, other techniques can be used, such as, for example, ionizing radiation or ultraviolet radiation in combination with an included free radical photoinitiator (e.g., benzophenone or α-cyclohexyl-α, α-dimethoxyacetophenone).

[0102] Examples of suitable thermal initiators include peroxides (e.g., benzoyl peroxide, dibenzoyl peroxide, dilauroyl peroxide, cyclohexane peroxide, and methyl ethyl ketone peroxide), hydroperoxides (e.g., butyl hydroperoxide and isopropylbenzene hydroperoxide), dicyclohexyl peroxydicarbonate, tert-butyl perbenzoate, and azo compounds (such as 2,2-azo-bis(isobutyronitrile) (AIBN)), and combinations thereof. Examples of commercially available thermal initiators include those available under the trade designation "VAZO" from The Chemours Company (Wilmington, Delaware) (such as VAZO 64 (2,2'-azobis(isobutyronitrile)), VAZO 52, VAZO 65, and VAZO 68); and those available under the trade designation "CELOGEN" from CelChem LLC, Naples, Florida. Peroxides are available from a variety of sources.

[0103] The free radical polymerization initiator is used in an amount effective to cause free radical polymerization of the free radical polymerizable monomer. The amount will generally vary depending on factors such as, for example, the type of initiator, the molecular weight of the initiator, the intended application of the resulting adhesive composition, and polymerization process factors such as temperature. The photoinitiator can be used in any amount effective to promote polymerization of the monomer (e.g., 0.1 to about 5 parts by weight, 0.2 to about 2 parts by weight, or about 0.1 to about 1 part by weight per hundred parts by weight of the monofunctional monomer used to prepare the acrylic polymer).

[0104] If it is desired to control the molecular weight distribution of the stable copolymer, a free radical polymerization chain transfer agent can be added to the combined monomers before polymerization. Examples of available chain transfer agents include, but are not limited to, those selected from the group consisting of carbon tetrabromide, alcohols, mercaptans, and mixtures thereof. Some preferred examples include thioglycerol, isooctyl thioglycolate, tert-dodecyl mercaptan, tert-nonyl mercaptan, n-octyl mercaptan, 1,8-dimercapto-3,6-dioxaoctane (DMDO), isooctyl 3-mercaptopropionate, and KF-2001 side chain type / mercapto-modified reactive silicone purchased from Shinetsu Chemical Industry Co., Ltd.

[0105] If present, chain transfer agents are typically present in amounts up to about 1 part by weight, typically from about 0.01 to about 0.5 parts by weight, and if used, preferably from about 0.05 to about 0.2 parts by weight, based on 100 parts by weight of the combined monomers present.

[0106] Adhesive composition

[0107] The stabilizing copolymers according to the present disclosure can be used, for example, to stabilize the curable foam produced during the manufacture of certain acrylic adhesives, typically pressure-sensitive adhesives. Pressure-sensitive adhesive compositions (PSAs) are known to those of ordinary skill in the art and have properties including: (1) strong and persistent tack at room temperature, (2) adhesion with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be cleanly removed from an adherend.

[0108] For example, an adhesive composition (e.g., a PSA) may include a polymeric material derived from a polymerizable adhesive precursor composition comprising at least one stable copolymer according to the present disclosure, at least one alkyl (meth)acrylate having 7 to 24 carbon atoms, and at least one optional polar free radical polymerizable monomer and an optional free radical polymerizable crosslinker (e.g., a monomer having at least two free radical polymerizable groups). In some embodiments, the adhesive compositions are foams, while in other embodiments, they are not foams.

[0109] Typically, the stabilizing copolymer according to the present disclosure, if included in the polymerizable composition for use in the present disclosure, is typically present in an amount of 0.5 wt % to 20 wt %, 1 wt % to 15 wt %, 1 wt % to 10 wt %, or even 1 wt % to 5 wt %, however this is not required.

[0110] Useful acrylates may include acrylates or methacrylates of monohydric alcohols having 4 to 20, 4 to 18, 4 to 16, 4 to 12, 6 to 12, or 8 to 12 carbon atoms, which may be linear, branched, cyclic, or polycyclic. Examples of suitable monomers represented by Formula V include n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, hexyl acrylate, cyclohexyl acrylate, heptyl acrylate, isopentyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, 2-octyl acrylate, isooctyl acrylate, n-nonyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, n-dodecyl acrylate, isomyristyl acrylate, n-tridecyl acrylate, n-tetradecyl acrylate, lauryl acrylate, stearyl acrylate, isostearyl acrylate, isobornyl acrylate, 2-methylbutyl acrylate, 4-methyl-2-pentyl acrylate, octadecyl acrylate, 2-propylheptyl acrylate, methacrylates of the foregoing acrylates, and combinations thereof.

[0111] Additional examples of useful acrylic acid esters may include a mixture of at least two or at least three structural isomers of a secondary alkyl (meth)acrylate represented by the following formula:

[0112]

[0113] Where R 7 and R 8 Each independently is C 1 To C 30 Saturated straight chain alkyl group; R 7 and R 8 The sum of the number of carbon atoms in is 7 to 31; and R 1 As previously defined (i.e., hydrogen or methyl). 7 and R 8 The sum of the number of carbons in can be 7 to 27, 7 to 25, 7 to 21, 7 to 17, 7 to 11, or 7. Methods for making and using such monomers and monomer mixtures are described in US Pat. No. 9,102,774 (Clapper et al.).

[0114] Useful optional (but preferred) polar free radical polymerizable monomers are more polar than the alkyl (meth)acrylate monomers. Examples of suitable optional polar free radical polymerizable monomers that can be used to prepare acrylic PSA include acrylic acid (e.g., acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid), acrylamide (e.g., acrylamide, methacrylamide, N-ethylacrylamide, N-hydroxyethylacrylamide, N-octylacrylamide, N-tert-butylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-ethyl-N-dihydroxyethylacrylamide, and methacrylamides of the foregoing acrylamides), hydroxy or amino substituted acrylates (e.g., 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, 8-hydroxyoctyl acrylate, 10-hydroxydecyl acrylate, 12-hydroxylauryl acrylate, (4-hydroxymethylcyclohexyl)methyl acrylate, dimethyl acrylate, 12-hydroxydecyl acrylate, 13-hydroxydecyl acrylate, 14-hydroxydecyl acrylate, 15-hydroxydecyl acrylate, 16-hydroxydecyl acrylate, 17-hydroxydecyl acrylate, 18-hydroxydecyl acrylate, 19-hydroxydecyl acrylate, 20-hydroxydecyl acrylate, 21-hydroxydecyl acrylate, 23-hydroxydecyl acrylate, 24-hydroxydecyl acrylate, 25-hydroxydecyl acrylate, 26-hydroxydecyl acrylate, 27-hydroxydecyl acrylate, 28-hydroxydecyl acrylate, 29-hydroxydecyl acrylate, 30-hydroxydecyl acrylate, 31-hydroxydecyl acrylate, 32-hydroxydecyl acrylate, 33-hydroxydecyl acrylate,

[0063] The invention also includes but is not limited to styrene monomers (e.g., 4-tert-butoxystyrene, 4-(tert-butyl)styrene, 4-chloromethylstyrene, 3-chlorostyrene, 2-(diethylamino)ethylstyrene, 2-methylstyrene, 4-methylstyrene, 4-nitrostyrene and 4-vinylbenzoic acid), maleates and combinations thereof.

[0115] In some embodiments, the optional polar free radical polymerizable monomer acrylic polymer comprises at least one of acrylic acid, methacrylic acid, acrylamide, acrylonitrile, methacrylonitrile, N-substituted acrylamide, N,N-disubstituted acrylamide, hydroxyalkyl acrylate, N-vinyl caprolactam, N-vinyl pyrrolidone, maleic anhydride, or itaconic acid.

[0116] For example, other useful monomers that may be present in the acrylate-based adhesive composition include ethylenically unsaturated monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, and combinations thereof.

[0117] Typically, the weight ratio of the at least one (meth)acrylic acid alkyl ester having 7 to 24 carbon atoms to the at least one optional polar free-radically polymerizable monomer is at least 50:50, at least 60:40, at least 70:30, at least 80:20, at least 85:15, at least 90:10 or at most 95:5 to 99:1. Typically, the at least one (meth)acrylic acid alkyl ester having 7 to 24 carbon atoms accounts for at least 90% by weight, preferably at least 95%, of the polymerizable binder precursor composition, relative to the at least one optional polar free-radically polymerizable monomer.

[0118] Although organic solvents and / or water may be included in the polymerizable binder precursor composition, preferably they are not present in amounts other than an indeterminate amount due to impurities in one or more components.

[0119] Exemplary crosslinking agents include polyfunctional monomers having two or more free-radically polymerizable groups (e.g., di(meth)acrylates, tri(meth)acrylates, tetra(meth)acrylates). Suitable polyfunctional monomers include diacrylates of diols such as ethylene glycol diacrylate, diethylene glycol diacrylate, propylene glycol diacrylate, butylene glycol diacrylate, butane-1,3-diyl diacrylate, pentylene glycol diacrylate, hexylene glycol diacrylate (including 1,6-hexylene glycol diacrylate), heptylene glycol diacrylate, octylene glycol diacrylate, nonylene glycol diacrylate, decylene glycol diacrylate, and dimethacrylates of any of the foregoing diacrylates. Further suitable polyfunctional monomers include polyacrylates of polyols such as glycerol triacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, neopentyl glycol diacrylate, dipentaerythritol tetraacrylate, and combinations thereof. Further suitable polyfunctional crosslinking monomers include polyfunctional acrylate oligomers containing two or more acrylate groups. The polyfunctional acrylate oligomers can be urethane acrylate oligomers, epoxy acrylate oligomers, polyester acrylates, polyether acrylates, polyacrylate acrylates, methacrylates of any of the foregoing acrylates, or combinations thereof.

[0120] Crosslinking can also be achieved without a crosslinking agent by using high-energy radiation such as gamma radiation or electron beam radiation.

[0121] The amount of the crosslinking agent (if present) is typically in an amount of 0.05% to 5% by weight, 0.1% to 3% by weight, or even 0.1% to 1.5% by weight of the polymerizable binder precursor composition, although this is not necessary.

[0122] In some embodiments, the free-radically polymerizable binder precursor composition further comprises at least one free-radical polymerization chain transfer agent.

[0123] In some embodiments, the free radically polymerizable binder precursor composition comprises a combined 0.5 wt % to 20 wt % of at least one stabilizing copolymer and 80 wt % to 99.5 wt % of the free radically polymerizable component, based on the combined total weight of the stabilizing copolymer and the free radically polymerizable component.

[0124] The polymerizable binder precursor composition may be cured using a thermal free radical initiator as described above, but is typically cured photochemically.

[0125] method

[0126] Useful solventless polymerization methods are disclosed in U.S. Pat. No. 4,379,201 (Heilmann et al.). Initially, a mixture of the first monomer and the second monomer may be polymerized with a portion of the free radical photoinitiator by exposing the mixture to ultraviolet radiation in an inert environment for a time sufficient to form a coatable base syrup, and then adding a crosslinker and the remainder of the photoinitiator. The crosslinking may be, for example, any of the above-described multifunctional crosslinking monomers in any of the amounts described above. This final syrup containing the crosslinker (e.g., which may have a Brook viscosity of about 500 centipoise (cps) to about 10,000 cps at 23° C., about 100 cps to about 6,000 cps at 23° C., or about 5,000 cps to about 7,500 cps at 23° C., as measured with a No. 4 LTV spindle at 60 rpm) may then be coated onto a substrate. After the slurry is coated on a substrate, further polymerization and crosslinking can be carried out in an inert environment (such as nitrogen, carbon dioxide, helium and argon, excluding oxygen). A sufficiently inert atmosphere can be achieved by covering a layer of the photosensitive slurry with a polymer film (such as a silicone-treated polyester film that is transparent to ultraviolet radiation or electron beam irradiation).

[0127] Any suitable light source can be used, including fluorescent UV bulbs, mercury lamps (e.g., low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps), xenon lamps, metal halide lamps, electrodeless lamps, incandescent lamps, light emitting diodes (LEDs), and lasers. For broadband light sources (e.g., fluorescent UV bulbs, mercury lamps, or incandescent lamps), filters can be used to narrow the wavelength range to within or outside the wavelength absorbed by the ultraviolet light absorber and / or to change the intensity of the light source.

[0128] The polymerizable binder precursor composition may also include other ingredients such as curing agents, curing accelerators, catalysts, tackifiers, plasticizers, dyes, flame retardants, adhesion promoters (e.g., coupling agents such as silane coupling agents), pigments, impact modifiers, flow control agents, foaming agents, fillers (e.g., talc, zinc oxide and fused silica), glass and polymer microspheres and microparticles, conductive particles, thermally conductive particles, fibers, antistatic agents, antioxidants such as hindered phenols, amines and sulfur and phosphorus hydroperoxide decomposers, UV absorbers, stabilizers (e.g., hindered amine light stabilizers and heat stabilizers) and viscosity modifiers such as fumed silica.

[0129] The foamable adhesive composition according to the present disclosure and / or the foamable adhesive composition made by the method of the present disclosure may include hollow microspheres (e.g., hollow ceramic (or glass) microspheres or hollow polymer microspheres, such as elastomeric particles available from Akzo Nobel, Amsterdam, The Netherlands under the trade name EXPANCEL. Examples of hollow ceramic microspheres include alumina / silica microspheres with a particle size ranging from 5 microns to 300 microns and a specific gravity of 0.7 (FILLITE, Pluess-Stauffer International, Oftringen, Switzerland), aluminum silicate microspheres with a specific gravity of about 0.45 to about 0.7 (Z-LIGHT), calcium carbonate-coated polyvinylidene copolymer microspheres with a specific gravity of 0.13 (DUALITE 6001AE, Pierce & Stevens Chemical Co., Ltd., Cleveland, Ohio), and polyvinylidene copolymer microspheres with a specific gravity of 0.13 (Pierce & Stevens Chemical Co., Ltd., Cleveland, Ohio). Corp., Cleveland, Ohio), and glass bubbles sold by 3M Company, Saint Paul, Minnesota, as 3M GLASS BUBBLES of grades K1, K15, K20, K25, K37, K46, S15, S22, S32, S35, S38, S38HS, S38XHS, S42HS, S42XHS, S60, S60HS, iM30K, iM16K, XLD3000, XLD6000, and G-65, and any of the HGS series of 3M GLASS BUBBLES. Foams containing hollow microspheres are referred to as composite foams. The foaming adhesive may also include a hydrocarbon elastomer as described in U.S. Pat. No. 5,024,880 (Vesley et al.).

[0130] In some embodiments, the adhesive composition (and its precursor) includes a tackifier, which can be used to increase the stickiness of the surface of the PSA. In some embodiments, the foam composition does not include a tackifier. Useful tackifiers have a number average molecular weight of up to 10,000 g / mol, a softening point of at least 70°C (as determined using a ring and ball instrument), and a glass transition temperature of at least -30°C (as determined by differential scanning calorimetry). Useful tackifiers are generally amorphous. In some embodiments, the tackifier is miscible with the polymer of the PSA so that macroscopic phase separation does not occur in the PSA. In some embodiments, the PSA also has no microscopic phase separation. In some embodiments, the tackifier comprises at least one of the following: rosin, rosin esters, esters of hydrogenated rosin, polyterpenes (e.g., those based on α-pinene, β-pinene or limonene), C 5 / 、C 9 / or C 5 / C 9 Hydrocarbon resins, aliphatic hydrocarbon resins (e.g., those based on cis- or trans-piperylene, isoprene, 2-methyl-but-2-ene, cyclopentadiene, dicyclopentadiene, or combinations thereof), aromatic resins (e.g., those based on styrene, α-methylstyrene, methylindene, indene, coumarone, or combinations thereof), or mixed aliphatic-aromatic hydrocarbon resins. Any of these tackifying resins may be hydrogenated (e.g., partially or fully). Examples of suitable tackifiers include those available under the following trade names: FLORAL, including FORAL 85E (a glycerol ester of highly hydrogenated refined gum rosin) commercially available from Eastman Chemical Middleburg BV, Middelburg, The Netherlands, FORAL 3085 (a glycerol ester of highly hydrogenated refined gum rosin) commercially available from Pinova, Brunswick, Georgia; ESCOREZ, including ESCOREZ 2520 and ESCOREZ 5615 (aliphatic / aromatic hydrocarbon resins) commercially available from ExxonMobil Corp., Houston, Texas; ARKON, such as ARKON commercially available from Arakawa Chemical Inc., Chicago, Illinois P125 (a fully hydrogenated hydrocarbon resin), and REGALITE, such as REGALITE 7100 (a partially hydrogenated hydrocarbon resin), commercially available from Eastman, Kingsport, Tennessee.

[0131] In some embodiments, the adhesive composition (and its precursor) comprises at least about 1 wt % and up to about 50 wt % of a tackifier based on the total weight of the vehicle. In some embodiments, the tackifier is present in a range of 1-25 wt %, 2-20 wt %, 2-15 wt %, 1-10 wt %, or 3-10 wt % based on the total weight of the vehicle.

[0132] Plasticizers may be added, for example, to reduce the vitrification of the adhesive composition. Suitable plasticizers include various polyalkylene oxides (e.g., polyethylene oxide or propylene oxide), adipates, formates, phosphates, benzoates, phthalates, polyisobutylene, polyolefins and sulfonamides, naphthenic oils, plasticizing aids (such as those materials described as plasticizers in "Dictionary of Rubber", KF Heinisch, 1974, p. 359, John Wiley & Sons, New York), oils, elastomeric oligomers and waxes. The amount of plasticizer used (if used) will depend on the nature of the plasticizer and the compatibility of the plasticizer with the vehicle.

[0133] In some embodiments, the adhesive compositions of the present disclosure and / or adhesive compositions made by the methods of the present disclosure are substantially free of solvents. Commonly used organic solvents include aliphatic and alicyclic hydrocarbons (e.g., hexane, heptane and cyclohexane), hydrocarbon solvents (e.g., benzene, toluene, xylene and d-limonene); non-cyclic and cyclic ketones (e.g., acetone, methyl ethyl ketone and methyl isobutyl ketone, pentanone, hexanone, cyclopentanone and cyclohexanone); ethers (e.g., ethyl ether, glyme, diglyme, diisopropyl ether and tetrahydrofuran), esters (e.g., ethyl acetate and butyl acetate), sulfoxides (e.g., dimethyl sulfoxide), amides (e.g., N,N-dimethylformamide, N,N-dimethylacetamide and N-methyl-2-pyrrolidone), halogenated solvents (e.g., methyl chloroform, 1,1,2-trichloro-1,2,2-trifluoroethane, trichloroethylene and trifluorotoluene), and alcohol solvents (e.g., methanol, ethanol, or propanols such as (isopropanol)). The foam composition may be substantially free of any of these solvents.

[0134] The term "substantially free" means that the foam composition may contain up to 0.5%, 0.1%, 0.05%, or 0.01% by weight of any of these solvents, or may be free of any of these solvents. These percentages are based on the total weight of the foam composition.

[0135] In some embodiments, the adhesive composition (and its precursor) comprises a silane coupling agent. Examples of useful silane coupling agents include many of the silanes listed above that can be used to treat nanoparticles, as well as epoxysilanes, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethoxydimethoxysilane, and 3-glycidoxypropylmethoxytriethoxysilane; and aminosilanes, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane. The silane coupling agent may be used in an amount of about 0.05 wt % or more, or about 0.1 wt % or more and about 2 wt % or less, or about 1 wt % or less, relative to the total weight of the adhesive composition.

[0136] In some embodiments, the adhesive composition of the present disclosure and / or the adhesive composition manufactured by the method of the present disclosure further comprises a blowing agent. Available blowing agents include physical blowing agents and chemical blowing agents, any of which can be inorganic blowing agents or organic blowing agents. Available chemical foaming mechanisms include in situ generation of gas by chemical reaction; decomposition of components of the composition, for example, components that release gas upon thermal decomposition; evaporation of components of the composition, for example, liquid gas; volatilization of gas in the composition by reducing the pressure on the composition or heating the composition; and combinations thereof.

[0137] Examples of chemical blowing agents include water, azo molecules, carbonate (or ester) molecules, and hydrazide molecules (including, for example, 4,4'-oxybis(benzenesulfonyl)hydrazine, 4,4'-oxybenzenesulfonyl semicarbazide, azodicarbonamide, p-toluenesulfonyl semicarbazide, barium azodicarboxylate, azobisisobutyronitrile, benzenesulfonylhydrazide, trihydrazinotriazine, metal salts of azodicarboxylic acid, oxalic acid hydrazide, 1,2-hydrazonocarboxylates (hydrazocarboxylates), diphenyl ether-4,4'-disulfonylhydrazide, tetrazole compounds, sodium bicarbonate, ammonium bicarbonate, carbonate (or ester) compounds, and preparations of polycarbonate, a mixture of citric acid and sodium bicarbonate, N,N'-dimethyl-N,N'-dinitroso-terephthalamide, N,N'-dinitrosopentamethylenetetramine, and combinations thereof). Water is a blowing agent that can be used to make polyurethane foam. The water reacts with the isocyanate to ultimately form carbon dioxide, which causes the polyurethane to foam.

[0138] Suitable inorganic physical blowing agents include, for example, nitrogen, argon, oxygen, water, air, helium, sulfur hexafluoride, and combinations thereof.

[0139] Available organic physical blowing agents include carbon dioxide, aliphatic hydrocarbons, aliphatic alcohols, completely and partially halogenated aliphatic hydrocarbons, including for example methylene chloride, and combinations thereof. Examples of suitable aliphatic hydrocarbon blowing agents include members of the hydrocarbons of the alkane series, including for example methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane and blends thereof. Available aliphatic alcohols include for example methanol, ethanol, n-propyl alcohol, isopropyl alcohol and combinations thereof. Suitable completely or partially halogenated aliphatic hydrocarbons include for example fluorocarbons, chlorocarbons and chlorofluorocarbons and combinations thereof.

[0140] Examples of suitable halogenated (in some embodiments, fluorinated) blowing agents include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane (HFC-134), 1,1,1,3,3-pentafluoropropane, pentafluoroethane (HFC-125), difluoromethane (HFC-32), perfluoroethane, 2,2-difluoropropane, 1,1,1-trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, perfluorobutane, Fluorocyclobutane, methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro-1,1-difluoroethane (HCFC-142b), chlorodifluoromethane (HCFC-22), 1,1-dichloro-222-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), dichlorotetrafluoroethane (CFC-114), chloroheptafluoropropane and dichlorohexafluoropropane and combinations thereof. In some embodiments, the blowing agent is unhalogenated. In some embodiments, the blowing agent is unfluorinated.

[0141] The blowing agents can be used as single components, in mixtures and combinations thereof, and in mixtures with other co-blowing agents.The blowing agent is added to the composition in an amount sufficient to achieve the desired foam density.

[0142] In some embodiments, the foam adhesive composition of the present disclosure and / or the foam adhesive composition manufactured by the method of the present disclosure also includes a nucleating agent. The nucleating agent can be any conventional nucleating agent. The amount of the nucleating agent to be added can be selected according to the density of the desired cell size, the selected blowing agent and the vehicle. The example of the inorganic nucleating agent in the form of small particles includes clay, talc, silicon dioxide and diatomaceous earth.

[0143] Organic nucleating agent can decompose or react at a given temperature. An example of organic nucleating agent is a combination of an alkali metal salt of a polycarboxylic acid with a carbonate or bicarbonate. Examples of available alkali metal salts of polycarboxylic acids include monosodium salts (i.e., sodium hydrogen tartrate) of 2,3-dihydroxy-butenedioic acid, monopotassium salts (i.e., potassium hydrogen succinate) of butenedioic acid, trisodium salts (i.e., sodium citrate) and tripotassium salts (i.e., potassium citrate) of 2-hydroxy-1,2,3-propanetricarboxylic acid, disodium salts (i.e., sodium oxalate) of oxalic acid and polycarboxylic acids (such as, 2-hydroxy-1,2,3-propanetricarboxylic acid), and combinations thereof. Examples of carbonates and bicarbonates include sodium carbonate, sodium bicarbonate, potassium bicarbonate, potassium carbonate, calcium carbonate and combinations thereof. An expected combination is a monoalkali metal salt (such as, monosodium citrate or monosodium tartrate) of a polycarboxylic acid with a carbonate or bicarbonate. It is expected that a mixture of different nucleating agents can be added to a vehicle. Other useful nucleating agents include a stoichiometric mixture of citric acid and sodium bicarbonate.

[0144] Can use multiple mechanism (comprising mechanical mechanism, chemical mechanism and their combination) to form gas void in adhesive composition to make adhesive composition precursor foam.Available mechanical foaming mechanism comprises stirring (for example, shaking, stirring and oscillating composition), injecting gas (for example, inserting nozzle into below the composition surface and blowing gas into the composition, and their combination) into composition.In some embodiments, introducing whipping agent comprises stirring composition or injecting gas into composition at least one operation.In some embodiments, whipping agent comprises at least one of air, nitrogen, oxygen, carbon dioxide, helium, argon or nitrous oxide.

[0145] The curing of the adhesive precursor composition can be accomplished by heating (e.g., by including a thermal free radical initiator as described above) and / or by exposure to actinic radiation (e.g., ultraviolet and / or visible light, gamma rays or electron beams) and / or chemical agents. These exposures to actinic radiation are generally preferred because they are easy to implement. In those embodiments in which the polymer matrix contains ethylenically unsaturated free radical polymerizable, the adhesive layer preferably also includes a photoinitiator (i.e., for free radical polymerization). If present, the amount of the photoinitiator is generally an effective amount, which is at least sufficient to cause the adhesive layer to be at least partially cured when exposed to sufficient actinic radiation. Typically, the effective amount of the photoinitiator accounts for less than 5% by weight of the total adhesive layer, more typically less than 3% by weight, and more typically less than 1% by weight. It will be recognized that even with polymerizable (meth)acrylate groups remaining, curing can also be complete.

[0146] Exemplary photoinitiators include α-cleaving photoinitiators such as benzoin and its derivatives, such as α-methylbenzoin; α-phenylbenzoin; α-allylbenzoin; α-benzylbenzoin; benzoin ethers, such as benzil dimethyl ketal (available under the trade name IRGACURE 651 from Ciba Specialty Chemicals, Tarrytown, New York), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its derivatives, such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (available under the trade name DAROCUR 1173 from Ciba Specialty Chemicals) and 1-hydroxycyclohexyl phenyl ketone (available under the trade name IRGACURE 184 from Ciba Specialty Chemicals); 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (available under the trade name IRGACURE 907 from Ciba Specialty Chemicals); 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (available under the trade name IRGACURE 369 from Ciba Specialty Chemicals); titanium complexes such as bis(η 5 -2,4-cyclopentadien-1-yl)bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium (available from Ciba Specialty Chemicals under the trade name CGI 784DC); and mono- and bisacylphosphines (available from Ciba Specialty Chemicals under the trade names IRGACURE 1700, IRGACURE 1800, IRGACURE 1850, and DAROCUR 4265). A useful photoinitiator, a difunctional alpha hydroxy ketone, is available from Lamberti SpA, Albizzate, Italy under the trade name ESACURE ONE.

[0147] Preferably, if an acylphosphine or acylphosphine oxide photoinitiator is utilized, it is combined with a photoinitiator having a high extinction coefficient at one or more wavelengths of actinic radiation (e.g., 2-hydroxy-2-methyl-1-phenyl-1-propanone). Such combinations generally facilitate surface curing while keeping the level of expensive photoinitiator low.

[0148] Other useful photoinitiators include anthraquinones (eg, anthraquinone, 2-ethylanthraquinone, 1-chloroanthraquinone, 1,4-dimethylanthraquinone, 1-methoxyanthraquinone) and benzophenone and its derivatives (eg, phenoxybenzophenone, phenylbenzophenone).

[0149] The adhesive composition can be included in a tape such as a pressure-sensitive adhesive tape. Useful adhesive tape constructions include, for example, a substrate (e.g., a core layer (e.g., see below) disposed on a substrate (e.g., a core layer (e.g., Figure 1) or release liner), and optionally wound in roll form. In some embodiments, the foam tape construction includes an adhesive composition disposed on the surface of the foam core, which forms a tape having an adhesive layer on one side of the foam tape, i.e., a single-layer coated adhesive tape. In another embodiment, the foam composition can be in the form of a tape having an adhesive layer on both major surfaces of the foam core, which is referred to as a double-layer coated foam tape.

[0150] The present disclosure provides a method for making an adhesive tape, the method comprising applying a foam composition to a substrate. After the adhesive composition can be foamed using any of the above methods, that is, after a gap is formed therein, the adhesive composition is applied to the substrate. The foamed adhesive composition can be applied to the substrate using a variety of methods (e.g., dip coating, spray coating, brush coating, roller coating, rod coating). In some embodiments, the composition can be applied to the liner using a notched rod having a gap setting for providing a desired thickness above the liner, and another liner can be added to maintain a gap of the desired thickness. Although any of the foamed adhesive compositions described in any of the embodiments of the present invention can be applied to the substrate, in some embodiments, the vehicle comprises a monomer and an optional polymer, and the method further comprises polymerizing the monomer. In some embodiments, the method further comprises crosslinking the foamed composition. When any UV light source in the UV light source described above is used for polymerization or crosslinking, any useful amount of UV irradiation can be used, such as about 1000mJ / cm 2 Up to about 10000mJ / cm 2 , about 1000mJ / cm 2 Up to about 5000mJ / cm 2 or about 1000mJ / cm 2 Up to about 3000mJ / cm 2 .

[0151] Adhesive articles have a variety of useful applications, including, for example, bonding two substrates together; mounting applications using articles including hooks, hangers and brackets; joining applications including adhering two or more containers (e.g., boxes) together for later separation; bonding articles to surfaces (such as, for example, walls, floors, ceilings and counters) and replacing mechanical fasteners, fillers or liquid glues. When bonding rough or irregular surfaces, the properties and formulation of the foam tape can be selected to provide a foam tape that evenly distributes stress over the bonding area. Other adhesive foam applications include, for example, as a structural adhesive and a foam-in-place adhesive.

[0152] The adhesive composition may also be subjected to post-processing including, for example, die cutting, cross-linking, and sterilization.

[0153] Products

[0154] The adhesive composition according to the present disclosure can be used to manufacture articles. Figure 1 , the exemplary adhesive article 100 includes a substrate (shown as a foam core layer) 110 sandwiched between a first adhesive layer 120 and an optional second adhesive layer 130. Optional release liners 125, 135 are releasably attached to the first adhesive layer 120 and the second adhesive layer 130, respectively.

[0155] Although described as a foam core layer, virtually any adhered substrate may be used. Examples of suitable substrates include thermoplastic polymer films (eg, polyester), metal (including painted metal), glass, wood, drywall, and ceramic.

[0156] In some embodiments (not shown), such as a roll of double-sided adhesive tape, a single double-sided release liner may be used in place of the dual release liners.

[0157] Exemplary articles according to the present disclosure include various adhesive tapes, such as transfer tapes, single-sided adhesive tapes, double-sided adhesive tapes, or die-cut adhesive articles, which may be included in electronic devices, such as mobile phones, laptop computers, tablet computers, radios, and / or televisions.

[0158] 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.

[0159] Example

[0160] Unless otherwise indicated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight. Table 1 below describes the materials used in the examples.

[0161] Table 1

[0162]

[0163]

[0164] Preparation of 750A

[0165] A 500 mL three-necked round-bottom flask equipped with a Dean-Stark separator and a water condenser was charged with Carbowax 750 alcohol (112.4 g), toluene (119.6 g), phenothiazine (58.3 mg), acrylic acid (13.3 g) and p-toluenesulfonic acid (4.6 g, PTSA). The mixture was heated to reflux for twenty hours, and the water formed was collected in the Dean-Stark separator. The mixture was then cooled to 60° C. Calcium hydroxide (3.5 g) was added to neutralize PTSA and excess acrylic acid. The mixture was maintained at 60° C. for 30 minutes and then cooled to 25° C. for 6 hours under stirring. The solution was filtered and then concentrated under reduced pressure (20 torr) and heating (93° C.) to produce 118.1 g of an amber liquid, which solidified into a tan solid when cooled to room temperature. The amber liquid was dissolved in 78.7 g of ethyl acetate to prepare a 60% solid dark amber solution.

[0166] Preparation of 750MA

[0167] A 500 mL three-necked RB flask equipped with a Dean-Stark separator and a water condenser was charged with Carbowax 750 alcohol (112.4 g), toluene (119.6 g), phenothiazine (58.3 mg), methacrylic acid (15.8 g) and p-toluenesulfonic acid (PTSA, 4.6 g). The mixture was heated to reflux for twenty hours, and the water formed was collected in the Dean-Stark separator. The mixture was then cooled to 60° C. Calcium hydroxide (3.5 g) was added to neutralize PTSA and excess methacrylic acid. The mixture was maintained at 60° C. for 30 minutes and then cooled to 25° C. for 6 hours under stirring. The solution was filtered and then concentrated under reduced pressure (20 torr) and heating (93° C.) to produce 120.7 g of an amber liquid that solidified into a tan solid when cooled to room temperature.

[0168] Preparation of L44-acrylate :

[0169] Pluronic L44 alcohol (163.7 g), toluene (100.6 g), phenothiazine (49.4 mg), acrylic acid (7.3 g) and methanesulfonic acid (2.0 g, MSA) were charged into a 500 mL three-necked round-bottom flask equipped with a Dean-Stark separator and a water condenser. The mixture was heated to reflux for twenty hours, and the water formed was collected in the Dean-Stark separator. The mixture was then cooled to 60° C. Calcium hydroxide (2.9 g) was added to neutralize MSA and excess acrylic acid. The mixture was maintained at 60° C. for 30 minutes, and then cooled to 25° C. for 6 hours under stirring. The solution was filtered to produce an amber solution (255.0 g).

[0170] Preparation of S10A

[0171] Charge a 500 mL three-necked RB flask equipped with a Dean-Stark separator and a water condenser with Brij S-10 (100 g), toluene (112.2 g), phenothiazine (54.7 mg), acrylic acid (12.4 g), and p-toluenesulfonic acid (4.3 g). Heat the mixture under reflux for twenty hours and collect the water formed in the Dean-Stark separator. Then cool the mixture to 60 °C. Add calcium hydroxide (3.3 g) to neutralize the PTSA and the excess methacrylic acid. Hold the mixture at 60 °C for 30 minutes and then cool it with stirring to 25 °C for 6 hours. Filter the solution and then concentrate it under reduced pressure (20 Torr) and heating (93 °C) to yield 105.0 g of a dark amber liquid which solidifies to a tan solid when cooled to room temperature.

[0172] Examples EX-1 to EX-17 and Comparative Examples CE-A to CE-B and Preparation Examples PEX-1 and PEX-6

[0173] Copolymer preparation :

[0174] Add the reagents for the indicated compositions reported in Tables 2 to 7, values in parts by weight, to a vial containing a magnetic stir bar. Add VAZO 67 to ethyl acetate to produce a 0.33 wt% solution of VAZO 67 in ethyl acetate. Then add the ethyl acetate / VAZO 67 solution to the vial, where the weight of the solution is equivalent to the total weight of the reagents. Then purge the solution with nitrogen, seal the vial, and stir the mixture in a 60 °C water bath for 24 hours. After 24 hours by visual inspection, indicate the appearance of the solution under "Clear solution (Y / N)" in the given table, where "Y" equals "yes" and "N" equals "no".

[0175] Preparation of foaming monomer solutions including stable copolymers

[0176] Place 30.0 g of an acrylic monomer composition (90% 2-EHA, 10% AA) in a 4-ounce glass bottle containing a magnetic stir bar. Then add 0.3 g of the indicated stabilizing copolymer to the glass jar and seal the jar. Stir the solution for five minutes and then let it stand for five minutes, and then observe foaming by visual inspection. The results are reported in Tables 2 to 7. List the results under "Stable foam (Y / N)" for each stabilizing copolymer, where "Y" equals "yes" and "N" equals "no".

[0177]

[0178]

[0179] Table 4

[0180]

[0181] Table 5

[0182]

[0183] Table 6

[0184]

[0185] Table 7

[0186]

[0187] Examples 40-49

[0188] A coatable viscosity slurry polymer is prepared by mixing 92 parts of 2-EHA, 8 parts of AA, and OMNIRAD 651 photoinitiator (0.04 parts per hundred parts of monomers) until a homogeneous mixture is obtained. The mixture is purged with nitrogen while stirring for at least 5 minutes. While stirring, the mixture is exposed to a UV-A light source having a peak emission wavelength of 365 nm until a slurry having a viscosity deemed suitable for coating is formed. After UV-A light exposure, air is introduced. An additional 0.10 parts per hundred parts of OMNIRAD 651 photoinitiator and 0.06 parts per hundred parts of 1,6-hexanediol diacrylate are added to the slurry and mixed until a homogeneous mixture is obtained. The mixture is transferred to a high-shear stirrer, where 2 parts per hundred parts of A200 hydrophilic fumed silica is added and mixed until dispersed. The mixture is transferred to a low-shear stirrer, where 5 parts per hundred parts of K15 glass bubbles are added and mixed until dispersed.

[0189] The mixture is then placed under vacuum for 8 minutes to remove excess air introduced during mixing and then pumped through a pipe where various surfactants (as reported in Table 8) are introduced in series at various concentrations. Nitrogen is introduced in series through a sintered metal frit into the slurry / surfactant mixture. The mixture is then pumped through a rotor-stator mixer rotating at greater than 100 revolutions per minute (rpm) and pumped onto a silicone-coated polyester backing web. A rolling pile of the foaming slurry is established at the nip entrance set to a specific thickness. After passing through the nip, a second polyester backing is added to the top side of the foaming slurry and it is exposed to light sources of different times and intensities until the foaming slurry is converted to >97% polymeric PSA. The light source has a peak emission wavelength of approximately 365 nm and imparts a dose of approximately 1.7 J / cm 2 of dose.

[0190] The resulting final foamed PSA was measured for thickness and density and rated for visual appearance (as reported in Table 8), with a rating of 1 equaling poor appearance with many large pinholes present and a rating of 5 equaling excellent appearance with no pinholes present.

[0191]

[0192] The foregoing description, which is given to enable one of ordinary skill in the art to practice the present disclosure protected by the claims, should not be construed as limiting the scope of the present disclosure, which is defined by the claims and all equivalents thereof.

Claims

1. An adhesive composition, comprising a polymeric composition, wherein the polymeric composition comprises the following components: i) at least one stabilizing copolymer, the at least one stabilizing copolymer comprising: a) 20 to 90 wt% of at least one first divalent monomer unit, wherein the at least one first divalent monomer unit is represented by the formula: in: Each R 1 are independently H or methyl; Each R 2 are independently methyl or ethyl; Each R 3 are independently methylene, ethylene or propylene; Each R 4 are independently methyl, ethyl, propyl or butyl; Each n is independently an integer from 2 to 65; and b) 10 to 80 wt% of at least one second divalent monomer unit, the at least one second divalent monomer unit being represented by the formula: in: Each R 6 independently represent a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group; and Each X independently represents H or an alkyl group having 1 to 6 carbon atoms; and at least one first cross-linking agent; ii) at least one alkyl (meth)acrylate, the at least one alkyl (meth)acrylate having 7 to 24 carbon atoms; iii) at least one optional polar free radical polymerizable monomer; and iv) at least one second cross-linking agent.

2. The adhesive composition of claim 1 wherein the at least one optional polar free radical polymerizable monomer is present.

3. The adhesive composition according to claim 1 or 2, wherein the adhesive composition comprises 0.5 wt % to 20 wt % of component i), based on the combined total weight of components i), ii), iii), and iv); and 80% to 99.5% by weight of components ii), iii) and iv) combined.

4. The adhesive composition of claim 2, wherein components ii) and iii) are present in amounts of 50 to 99 wt% and 1 to 50 wt%, respectively, based on the total weight of the combination of components ii) and iii). 5 . The adhesive composition according to claim 1 , wherein the adhesive composition is a pressure-sensitive adhesive.

6. A product, wherein the product include: substrate; as well as An adhesive composition according to any one of claims 1 to 6 attached to the substrate.

7. The article of claim 7, wherein the article comprises a transfer tape, a single-sided adhesive tape, a double-sided adhesive tape, or a die-cut adhesive.

8. The article of claim 8, wherein at least one of the substrate or the adhesive composition comprises a foam.

9. A method for preparing an adhesive composition, the method comprising the following steps in sequence: I) providing a first polymerizable composition, the first polymerizable composition comprising: at least one alkyl (meth)acrylate; at least one optional first polar free radical polymerizable monomer; and at least one first free radical polymerization initiator; II) forming a syrup composition by partially polymerizing the first polymerizable composition, wherein the syrup composition comprises: 1 wt % to 20 wt % of a solute polymer, based on the total weight of the slurry composition, the solute polymer having a weight average molecular weight of at least 100,000 Daltons; and 80 wt % to 99 wt % of a solvent monomer based on the total weight of the syrup composition, the solvent monomer comprising: the at least one alkyl (meth)acrylate; and said at least one optional first polar free-radically polymerizable monomer; and III) preparing a second polymerizable composition, the second polymerizable composition comprising: said slurry composition; at least one optional second polar free-radically polymerizable monomer, wherein the at least one optional second polar free-radically polymerizable monomer and the at least one optional first polar free-radically polymerizable monomer may be the same or different; at least one stabilizing copolymer, the stabilizing copolymer comprising: a) 20 wt% to 90 wt% of at least one first divalent monomer unit, the at least one first divalent monomer unit being represented by the formula: wherein: Each R 1 are independently H or methyl; Each R 2 are independently methyl or ethyl; Each R 3 are independently methylene, ethenyl or propenyl; Each R 4 are independently methyl, ethyl, propyl or butyl; each n is independently an integer from 2 to 65; and b) 10 wt% to 80 wt% of at least one second divalent monomer unit, the at least one second divalent monomer unit being represented by the formula: wherein: Each R 6 independently represent a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group; and each X independently represents H or an alkyl group having 1 to 6 carbon atoms; at least one crosslinking agent; at least one second radical initiator; IV) foaming the second polymerizable composition to provide a foamed polymerizable composition; and V) polymerizing the foamed polymerizable composition to form the adhesive composition.

10. The method according to claim 10, wherein the second polymerizable composition further comprises a free-radical polymerization chain transfer agent.

11. The method according to claim 10 or 11, wherein at least one of the at least one first radical initiator or the at least one second radical initiator comprises a radical photoinitiator.

12. The method according to any one of claims 10 to 12, wherein step V) comprises exposing the second polymerizable composition to actinic electromagnetic radiation.

13. A stabilizing copolymer, the stabilizing copolymer comprising: a) 20 wt% to 90 wt% of at least one first divalent monomer unit, the at least one first divalent monomer unit being represented by the formula: wherein: Each R 1 are independently H or methyl; Each R 3 are independently methylene, ethenyl or propenyl; Each R 4 are independently methyl, ethyl, propyl or butyl; each n is independently an integer from 2 to 65; and b) 10 wt% to 80 wt% of at least one second divalent monomer unit, the at least one second divalent monomer unit being represented by the formula: wherein: Each R 6 independently represent a poly(alkyleneoxy) group, wherein the poly(alkyleneoxy) group comprises an ethyleneoxy group; and each X independently represents H or an alkyl group having 1 to 6 carbon atoms.

14. The stabilizing copolymer according to claim 14, wherein the poly(alkyleneoxy) group further comprises an isopropylideneoxy group.

15. The stabilizing copolymer according to claim 14 or 15, the stabilizing copolymer further comprising: c) greater than 0 wt% to 22 wt% of at least one divalent acidic (meth)acrylic monomer unit.

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