Primer compositions, adhesive systems, and related methods

Abstract

A primer composition, the primer composition comprising a polyacrylate dissolved in an organic solvent. The polyacrylate comprises at least 20% by weight of methyl methacrylate units, at least 15% by weight of monomeric units comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, at least 15% by weight of acrylic monomer units having an alkyl group having at least four carbon atoms, and an acrylic monomer unit having a carboxylic acid group in an amount of from 0.5% by weight to 10% by weight. An adhesive system includes a primer composition and an adhesive tape. A method of making a bonded article is also described.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Application No. 63 / 521130, filed June 15, 2023, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] Some tapes offer very high bond strength to a variety of clean substrates. In some cases, a primer can be applied prior to bonding to ensure maximum bond strength, which is desirable for certain applications.

[0004] U.S. Patent No. 10,640,656 (Moren et al.) describes a primer composition that provides adhesion between, for example, various substrates and double-sided tapes. U.S. Patent Nos. 9,234,122 (Schümann et al.), 9,080,083 (Schümann et al.), and 10,513,634 (Dietze et al.), and U.S. Patent Application Publications 2014 / 0113070 (Schümann et al.), 2017 / 0066947 (Dietze et al.), and 2017 / 0298230 (Schümann et al.) describe primer compositions comprising acrylate copolymers. U.S. Patent No. 10,385,159 (Urbach et al.) discloses a water-based primer composition for polycarbonate and polycarbonate blends. Summary of the Invention

[0005] This disclosure provides a composition that can be used as a primer, for example, for adhesive tapes. The primer composition comprises a polyacrylate dissolved in an organic solvent. The primer composition provides improved adhesion to a variety of substrates, as illustrated in the following examples. Advantageously, heat or radiation and reactive chemicals are not required in the primer or adhesive tape to provide beneficial adhesive properties.

[0006] In one aspect, this disclosure provides a primer composition comprising a polyacrylate dissolved in an organic solvent. The polyacrylate comprises at least 20% by weight of methyl methacrylate units based on the total weight of the monomer units in the polyacrylate, at least 15% by weight of monomer units comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, at least 15% by weight of acrylic monomer units comprising an alkyl group having at least four carbon atoms, and 0.5% to 10% by weight of acrylic monomer units comprising a carboxylic acid group. In some cases, the primer composition also does not contain polyamide.

[0007] In another aspect, this disclosure provides the use of the above composition as a base adhesive for adhesive tapes.

[0008] In another aspect, this disclosure provides an adhesive system comprising a primer composition and an adhesive tape. The primer is typically not a component of the adhesive tape. The adhesive tape may be a semi-structural adhesive tape.

[0009] In another aspect, this disclosure provides a method for manufacturing an adhesive article. The method includes applying the aforementioned primer composition to a surface of a first substrate, and applying a semi-structural tape to the surface of the first substrate with the primer composition.

[0010] In another aspect, this disclosure provides an article of manufacture which is bonded using the adhesive system disclosed herein and / or manufactured by the methods disclosed herein.

[0011] As used in this article: The term "alkyl group" and the prefix "alkane" have only C-C and CH bonds and include straight-chain, branched, and cyclic groups. In some embodiments, unless otherwise specified, the alkyl group has up to 30 carbons (in some embodiments, up to 20, 15, 12, 10, 8, 7, 6, or 5 carbons). The cyclic group can be monocyclic or polycyclic and, in some embodiments, has 3 to 10 cyclic carbon atoms and other alkyl substituents; As used herein, “aryl” and “aromatic” include carbocyclic aromatic rings or cyclic systems, for example, having one, two, or three rings and optionally containing at least one heteroatom (e.g., O, S, or N) in the ring, which is optionally substituted by up to five substituents, including one or more alkyl groups (e.g., methyl or ethyl) having up to four carbon atoms, alkoxy groups, halogen groups (i.e., fluorine, chlorine, bromine, or iodine), hydroxy groups, or nitro groups having up to four carbon atoms, examples of which include phenyl, naphthyl, biphenyl, fluorenyl, furanyl, thiophene, pyridinyl, quinolinyl, isoquinolinyl, indolyl, isoindolyl, triazolyl, pyrroleyl, tetrazolyl, imidazolyl, pyrazolyl, oxazolyl, and thiazolyl.

[0012] The terms "acrylic acid" and "polyacrylate" refer to both acrylic acid polymers, oligomers and monomers and methacrylic acid polymers, oligomers and monomers. The term "(meth)acryl" refers to acryl (also known in the art as acryloyl and acrylyl) and / or methacryl (also known in the art as methacryloyl and methacrylyl); and "Cure" refers to the process of creating a polymer chain from one or more monomers.

[0013] The term "polymer" refers to a molecule having a structure comprising multiple repeating units, actually or conceptually derived from one or more monomers. The term "monomer" refers to a low molecular weight molecule that can combine with other molecules to form a polymer. The term "polymer" includes homopolymers and copolymers, as well as homopolymers or copolymers that can be formed in miscible blends, for example, by co-extrusion or by reaction. The term "polymer" includes random polymers, block polymers, graft polymers, and star polymers. The term "polymer" includes oligomers.

[0014] The "monomer unit" of a polymer or oligomer is a segment of the polymer or oligomer derived from a single monomer.

[0015] Terms such as “a,” “an,” “the,” and “the” are not intended to refer to a single entity, but rather to encompass a general category of specific examples that can be used to illustrate the point. The terms “a,” “an,” “the,” and “the” are used interchangeably with the term “at least one (kind).”

[0016] The phrase "including at least one of..." followed by a list means including any item in the list or any combination of two or more items in the list.

[0017] The term "crosslinking" refers to linking polymers together through covalent chemical bonds (usually via crosslinking molecules or groups) to form a network polymer. Crosslinked polymers are generally characterized by insolubility, but can be swollen in the presence of suitable solvents. The term "crosslinking" includes partial crosslinking.

[0018] Unless otherwise specified, all numerical ranges include their endpoints and the non-integer values ​​between them (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0019] The features and advantages of this disclosure will be further understood upon consideration of the specific embodiments and the appended claims. Detailed Implementation

[0020] This disclosure provides a primer composition comprising a polyacrylate consisting of monomer units. The polyacrylate comprises at least 20 wt% methyl methacrylate monomer units based on the total weight of the monomer units in the polyacrylate. In some embodiments, the primer composition comprises at least 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt% methyl methacrylate monomer units based on the total weight of the monomer units in the polyacrylate. In some embodiments, the primer composition comprises 21 wt%, 22 wt%, 23 wt%, 24 wt%, or 25 wt% (wt%) to 65 wt%, 20 wt% to 60 wt%, 20 wt% to 40 wt%, or 40 wt% to 60 wt% methyl methacrylate based on the total weight of the monomer units in the polyacrylate. Methyl methacrylate is commercially available from various suppliers, including Evonik Performance Materials GmbH under the trade name “VISIOMER MMA”.

[0021] In some embodiments of the primer compositions disclosed herein, the polyacrylate comprises at least 15% by weight, based on the total weight of the monomer units in the polyacrylate, a monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide. In some embodiments, these monomer units comprise at least one of a tertiary amine or a tertiary amide. In some embodiments, these monomer units comprise at least one of a secondary amine or a tertiary amine. In some embodiments, the monomer unit comprising at least one of a secondary amine or a tertiary amine is represented by Formula I:

[0022] Wherein R1 is hydrogen, alkyl, or arylalkylene; R2 is alkyl or arylalkylene; or R1 and R2 together with the nitrogen atom to which they are bonded form a 5-, 6-, or 7-membered ring; V is alkylene or arylalkylene; W is -O- or -N(R3)-; R3 is hydrogen, alkyl, aryl, alkylarylene, or arylalkylene; and R is hydrogen or methyl. In some embodiments, R1 is hydrogen, and R2 is an alkyl group having at most four carbon atoms. In some embodiments, each of R1 and R2 is independently an alkyl group having at most four carbon atoms. In some embodiments, each of R1 and R2 is methyl. In some embodiments, W is -O- or -N(H)-. In some embodiments, W is -O-. In some embodiments, V is alkylene. In some embodiments, V is ethylene, propylene, or butylene. In some embodiments, V is ethylene.

[0023] In some embodiments, the monomeric unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide is an N-acryloylpiperidine unit, an N-methacryloylpiperidine unit, or a piperazine unit represented by Formula II:

[0024] R3 is hydrogen, alkyl, arylalkylene, or alkylcarbonyl; and R is hydrogen or methyl. In some embodiments, the monomer unit comprising the tertiary amide includes at least one of an N-vinyl-2-pyrrolidone unit, an N-vinylpiperidone unit, or an N-vinylcaprolactam unit. Combinations of any of these units are available.

[0025] In some embodiments, the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide includes a unit comprising at least one of the following: 2-(N,N-dimethylaminoethyl) (meth)acrylate, 2-(N,N-diethylaminoethyl) (meth)acrylate, 2-(tert-butylaminoethyl) (meth)acrylate, 2-(N,N-dimethylaminoethyl) (meth)acrylamide, 2-(N,N-diethylaminoethyl) (meth)acrylamide, 2-(tert-butylaminoethyl) (meth)acrylamide, N-(meth)acryloylpiperidine, N-vinylcaprolactam, and N-vinyl-2-pyrrolidone. In some embodiments, the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide includes a unit comprising at least one of 2-(N,N-dimethylaminoethyl) (meth)acrylate or N-vinyl-2-pyrrolidone. In some embodiments, these monomer units include at least one of 2-(N,N-dimethylaminoethyl) methacrylate or 2-(N,N-dimethylaminoethyl) acrylate.

[0026] In some embodiments, the primer composition comprises at least 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt% of monomer units comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, based on the total weight of the monomer units in the polyacrylate. In some embodiments, the primer composition comprises from 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt% to 40 wt% of monomer units comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, based on the total weight of the monomer units in the polyacrylate.

[0027] In some embodiments of the primer compositions disclosed herein, the polyacrylate comprises at least 15% by weight, based on the total weight of the monomer units in the polyacrylate, an acrylic monomer unit comprising an alkyl group having at least four carbon atoms. The alkyl group of the alkyl acrylate or alkyl methacrylate may be linear, branched, or cyclic (including polycyclic) and may have 4 to 24, 4 to 18, or 4 to 12 carbon atoms. Examples of suitable acrylic monomer units comprising an alkyl group having at least four carbon atoms include n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl acrylate, undecyl (meth)acrylate, propylene glycol, etc. Units of n-dodecyl acrylate, lauryl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, heptadecanyl acrylate, 2-propylheptyl acrylate, stearyl acrylate, n-nonyl acrylate, isononyl acrylate, isomyristyl acrylate, isostearyl acrylate, octadecyl acrylate, and docosyl acrylate. Suitable monomeric units further comprise units of mixtures of at least two or at least three structural isomers of secondary alkyl acrylates of formula III.

[0028] R4 and R5 are each independently C1 to C1. 30 The monomer comprises a saturated straight-chain alkyl group; the sum of the number of carbon atoms in R4 and R5 is 7 to 31; and R6 is H or CH3. In some embodiments, the sum of the number of carbon atoms in R4 and R5 may be 7 to 27, 7 to 25, 7 to 21, 7 to 17, 7 to 11, 7, 11 to 27, 11 to 25, 11 to 21, 11 to 17, or 11. Methods for manufacturing and using such monomers and monomer mixtures are described in U.S. Patent No. 9,102,774 (Clapper et al.). In some embodiments, the acrylic monomer unit comprising an alkyl group having at least four carbon atoms comprises a unit of at least one of 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, and isooctyl (meth)acrylate. In some embodiments, the acrylic monomer unit comprising an alkyl group having at least four carbon atoms comprises a unit of 2-ethylhexyl acrylate or 2-isooctyl acrylate.

[0029] In some embodiments, the primer composition comprises at least 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt% of acrylic monomer units containing alkyl groups having at least four carbon atoms, based on the total weight of the monomer units in the polyacrylate. In some embodiments, the primer composition comprises 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%, or 20 wt% to 50 wt%, 20 wt% to 40 wt%, 15 wt% to 45 wt%, 15 wt% to 30 wt%, or 30 wt% to 50 wt% of acrylic monomer units containing alkyl groups having at least four carbon atoms, based on the total weight of the monomer units in the polyacrylate.

[0030] The polyacrylates that can be used in the primer compositions of this disclosure comprise 0.5% to 10% by weight of an acrylic monomer unit containing a carboxylic acid group. Examples of suitable acrylic monomers containing a carboxylic acid group to provide these monomer units include methacrylic acid, acrylic acid, itaconic acid, maleic acid, fumaric acid, ethylacrylic acid, crotonic acid, citraconic acid, cinnamic acid, β-carboxyethyl acrylate, and β-methacryloyloxyethyl hydrosuccinate. In some embodiments, the acrylic monomer unit containing the carboxylic acid group is an acrylic monomer unit or a methacrylic acid monomer unit, and in some embodiments, it is an acrylic monomer unit. In some embodiments, the acrylic monomer unit containing the carboxylic acid group is present in the polyacrylate in an amount of 1% to 9% by weight, 1% to 8% by weight, or 1% to 5% by weight, 2% to 7% by weight, 2% to 6% by weight, or 2% to 4% by weight, based on the total weight of the monomer units in the polyacrylate.

[0031] In some embodiments, the polyacrylate comprises additional acrylic monomer units. In some embodiments, the methyl methacrylate unit, the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, the acrylic monomer unit comprising an alkyl group having at least four carbon atoms, and the acrylic monomer unit comprising a carboxylic acid group collectively account for at least 95%, 96%, 97%, 98%, 99%, or 100% by weight of the monomer units in the polyacrylate. In some embodiments, the polyacrylate does not contain acrylic monomer units comprising hydroxyl groups, or contains no more than 0.5%, 0.1%, 0.05%, 0.01%, or 0.005% by weight of acrylic monomer units comprising hydroxyl groups based on the total weight of the monomer units in the polyacrylate. In some embodiments, the polyacrylate is free of N-hydroxymethylacrylamide units and N-hydroxymethylmethacrylamide units, or contains no more than 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, or 0.005 wt% of N-hydroxymethylacrylamide units and N-hydroxymethylmethacrylamide units based on the total weight of the monomer units in the polyacrylate. In some embodiments, the polyacrylate is free of acrylic monomer units containing phosphate ester groups, or contains no more than 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, or 0.005 wt% of acrylic monomer units containing phosphate ester groups based on the total weight of the monomer units in the polyacrylate. In some embodiments, the polyacrylate is free of crosslinking monomer units or contains no more than 0.5 wt%, 0.1 wt%, 0.05 wt%, 0.01 wt%, or 0.005 wt% of crosslinking monomer units based on the total weight of the monomer units in the polyacrylate, including any of the crosslinking monomer units described below in conjunction with adhesive tapes.

[0032] In some embodiments, the primer compositions of this disclosure and / or primer compositions that can be used in the adhesive systems of this disclosure do not contain polyamide. In some embodiments, the primer compositions of this disclosure and / or primer compositions that can be used in the adhesive systems of this disclosure contain polyamide. In some embodiments, the polyamide is a dimer acid-based polyamide. The dimer acid may be used alone or in combination with other dimers. Suitable acids for manufacturing polyamides include any of those acids described in paragraphs

[0038] through

[0041] of U.S. Patent No. 2022 / 0347982 (Perez et al.), which is incorporated herein by reference. Suitable polyamines for manufacturing polyamides include any of those polyamines described in paragraphs

[0042] through

[0043] of U.S. Patent No. 2022 / 0347982 (Perez et al.), which is incorporated herein by reference. Commercially available polyamide resins include those traded under the name MACROMELT (e.g., MACROMELT OM 633, MACROMELT OM 641, MACROMELT OM 652, MACROMELT OM 673, MACROMELT OM 6208, MACROMELT 7001, MACROMELT 7002, MACROMELT 7003) from Henkel Corp., Rocky Hill, Conn., NY; those traded under the name UNI-REZ (e.g., UNI-REZ2600, UNI-REZ 2620, UNI-REZ 2700, and UNI-REZ 2720) from Kraton, Houston, TX, NY; and those traded under the name VERSAMID (e.g., VERSAMID...). The polyamide resins (100 and VERSAMID 115×70) were purchased from Gabriel Performance Chemicals, Ashtabula, Ohio. In some embodiments, the primer compositions of this disclosure and / or primer compositions that can be used in the adhesive systems of this disclosure contain a solvent. In some embodiments, the solvents available are non-flammable and have a low vapor pressure (e.g., less than 1 hPa at 20°C).Examples of solvents that can be used for primer compositions include polar solvents, such as monohydroxy alcohols having one to eight or more carbon atoms (e.g., methanol, ethanol, isopropanol, propanol, butanol, or isooctanol); polyols, such as glycols (e.g., ethylene glycol or propylene glycol), terminal alkyl glycols (e.g., 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, or 1,8-octanediol), polyethylene glycols (e.g., diethylene glycol, triethylene glycol, dipropylene glycol, or poly(propylene glycol), triols (e.g., Glycerin, trimethylolpropane) or pentaerythritol; polyol ethers (e.g., glycol ethers, such as ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, propylene glycol monomethyl ether, 2-butoxyethanol, 1-methoxy-2-propanol, 3-methoxy-3-methyl-1-butanol, 2-phenoxyethanol, or may be purchased under the trade name "DOWANOL" from Dow Chemical Company, Midland, Michigan. The solvent comprises, in some embodiments of Co., Midland, MI, diol ethers; dimethyl carbonate; propylene carbonate; diesters; limonene; methylsiloxanes; or ketones or esters each having up to six carbon atoms (e.g., methyl acetate, butyl acetate); and combinations thereof. In some embodiments, the solvent comprises at least one of dimethyl carbonate, propylene carbonate, limonene, or a monohydroxy alcohol having one to four or more carbon atoms. In some embodiments, the solvent comprises at least one of dimethyl carbonate, propylene carbonate, limonene, or isopropanol.

[0033] In some embodiments, the solvent comprises at least one of a polyol or a polyol ether having 2 to 10 (in some embodiments, 2 to 9 or 2 to 8) carbon atoms independently. In some embodiments, the solvent comprises a polyol. The term "polyol" refers to an organic molecule consisting of C, H, and O atoms linked together by C–H, C–C, C–O, or O–H single bonds and having at least two C–O–H groups. In some embodiments, the available polyols have 2 to 10, 2 to 8, or 2 to 6 carbon atoms. In some embodiments, the solvent comprises a polyol ether. The term "polyol ether" refers to an organic molecule consisting of C, H, and O atoms linked together by CH, CC, CO, OH single bonds or C=C double bonds, and the organic molecule can be derived, at least theoretically, from at least partially etherified polyols. In some embodiments, the polyol ether has at least one COH group and at least one COC bond. In some embodiments, the polyol ether has at least two COC bonds. Similarly, the term "polyol ether ester" refers to an organic molecule composed of C, H, and O atoms linked together by CH, CC, CO, OH single bonds and C=C double bonds, and such organic molecule can be derived, at least theoretically, from at least partial etherification and esterification of a polyol. In some embodiments, the polyol ether ester has at least one COC(O)-C group and at least one COC bond. Available polyol ethers and / or polyol ether esters may have 3 to 10, 3 to 8, or 5 to 8 carbon atoms. In some embodiments, the solvent comprises at least one of propylene carbonate, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methyl-1-butanol acetate, 2-phenoxyethanol, a diester, diethylene glycol monoethyl ether, dipropylene glycol dimethyl ether, or dipropylene glycol monomethyl ether.

[0034] In some embodiments, the solvent comprises at least 70%, 80%, 85%, or 90% by weight of the primer composition. In some embodiments, the solvent comprises no more than 98%, 97%, 96%, 95%, or 94% by weight of the primer composition. In some embodiments, excluding organic solvents, the polyacrylate comprises at least 95% by weight of the primer composition.

[0035] In some embodiments, the primer compositions of this disclosure and / or primer compositions that can be used in the adhesive systems of this disclosure comprise a humidity stabilizer, which may also be referred to as a water repellent. Examples of suitable humidity stabilizers include silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, O-methylcarbamate-methyl-methyldimethoxysilane, O-methylcarbamate-methyl-trimethoxysilane, O-ethylcarbamate-methyl-methyldiethoxysilane, O-ethyl-carbamate-methyl-triethoxysilane, 3-methacryloyloxypropyl-trimethoxysilane, methacryloyloxymethyl-trimethoxysilane, and methacryloyloxymethyl Methyldimethoxysilane, methacryloyloxymethyltriethoxysilane, methacryloyloxymethylmethyl-diethoxysilane, 3-acryloyloxypropyl-trimethoxysilane, acryloyloxymethyltrimethoxysilane, acryloyloxymethylmethyldimethoxysilane, acryloylmethyltriethoxysilane, acryloyloxymethylmethyldiethoxysilane, conventional alkylalkoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, further functionalized organosilanes, and aminosilanes also described below as adhesion promoters. In some embodiments, the primer composition contains at least 0.01% by weight, and in some embodiments, at least 0.03% by weight and not more than 5% by weight, 2% by weight, or 1% by weight of one or more moisture stabilizers.

[0036] In some embodiments, the primer compositions of this disclosure and / or primer compositions that can be used in the adhesive systems of this disclosure contain an adhesion promoter. Available adhesion promoters include those available under the trade names “A1120,” “A187,” and “A189” from OSI and those available under the trade name “Z9020” from Dow Chemical. Aminosilanes can be used as adhesion promoters. Examples of aminosilanes that can be used as adhesion promoters include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriisopropoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, γ-(2-aminoethyl)aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropylmethyldiethoxysilane, γ-(2-aminoethyl)aminopropyltriisopropoxysilane, γ-(6-aminohexyl)aminopropyltrimethoxysilane, and 3-(N-ethylamino)-2-methylpropyl Trimethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-vinylbenzyl-γ-aminopropyltriethoxysilane, [Nu],[Nu]'-bis[3-trimethoxysilyl]propyl]ethylenediamine, N-cyclohexylaminomethyltrimethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, and N-phenylaminomethyltrimethoxysilane. Suitable adhesion promoters also include titanates. In some embodiments, the primer composition further comprises titanate chelates. Examples of suitable titanate chelates include acetylacetone titanate chelates, triethanolamine titanate chelates, and those available under the trade name "TYZOR" from Dorfketal, Germany. In some embodiments, the primer composition contains at least 0.01% by weight, in some embodiments at least 0.1% by weight, or at least 0.5% by weight of one or more adhesion promoters. In some embodiments, the primer composition contains no more than 5% by weight, in some embodiments no more than 2% by weight of one or more adhesion promoters.

[0037] This disclosure provides an adhesive system comprising the primer composition described above in any of the embodiments of the primer composition, in combination with an adhesive tape. In some embodiments, the primer composition may be used to improve the adhesion of the adhesive tape to a first substrate (e.g., a first substrate to be bonded to a second substrate). In some embodiments, the primer composition is not a component of the adhesive tape. For example, the primer composition is not disposed on a tape backing to improve adhesion between the adhesive and the backing. Advantageously, neither heat or radiation nor reactive chemicals are required in the primer or adhesive tape to provide beneficial adhesive properties in the adhesive system of this disclosure. The adhesive tape typically adheres to the surface of the primer-coated substrate without forming covalent bonds. For example, the adhesive tape typically does not react with the primer composition to form covalent bonds. The adhesive system may be used, for example, to bond substrates.

[0038] For adhesive systems, any suitable adhesive tape can be used, and the primer composition can be used to improve the adhesion of various adhesives to a substrate. The adhesive on the adhesive tape can be in the form of a film or foam. In some embodiments, the adhesive is a single layer. In other embodiments, the adhesive tape comprises a multi-layer adhesive construction (such as a double-sided adhesive tape). For example, a multi-layer adhesive tape may have a first adhesive surface layer, a second adhesive surface layer, and a core layer positioned between the first and second adhesive surface layers. The core layer is typically a foam backing layer and can be an adhesive or non-adhesive foam. In another example, the multi-layer adhesive tape may have a first adhesive layer, a film backing, and a second adhesive layer. The film backing can be an adhesive or non-adhesive layer.

[0039] In some embodiments, adhesive tapes that can be used in the adhesive systems of this disclosure comprise pressure-sensitive adhesives based on (meth)acrylate copolymers. The glass transition temperature (Tg) of the (meth)acrylate copolymer is typically not greater than 20°C, not greater than 10°C, not greater than 0°C, not greater than -10°C, not greater than -20°C, not greater than -30°C, not greater than -40°C, or not greater than -50°C. The glass transition temperature can be measured using techniques such as differential scanning calorimetry and dynamic mechanical analysis. Alternatively, the Fox equation can be used to estimate the glass transition temperature based on the monomers used to form the adhesive. Lists of glass transition temperatures for homopolymers are available from numerous monomer suppliers, such as BASF Corporation (Houston, TX, USA), Polyscience, Inc. (Warrington, PA, USA), and Aldrich (St. Louis, MO, USA), and in various publications, such as Matti et al., *Journal of Chemical Information and Computer Science*, 2002, 42, 232-240, and are reported in many polymer property databases found at polymerdatabase.com.

[0040] (Meth)acrylate copolymers are typically formed from monomer compositions comprising at least one low-Tg monomer. As used herein, the term "low-Tg monomer" refers to a monomer whose Tg is not greater than 20°C when homopolymerized (i.e., the Tg of the homopolymer formed from the low-Tg monomer is not greater than 20°C). Suitable low-Tg monomers are often selected from alkyl (meth)acrylates, heteroalkyl (meth)acrylates, aryl-substituted alkyl acrylates, and aryloxy-substituted alkyl acrylates. Examples of low-Tg (meth)acrylate monomers are typically non-tertiary alkyl acrylates, but may be alkyl methacrylates having a straight-chain alkyl group having at least four carbon atoms. Examples of (meth)acrylate alkyl esters include n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, sec-butyl acrylate, n-pentyl acrylate, 2-methylbutyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, 4-methyl-2-pentyl acrylate, 2-methylhexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, 2-octyl acrylate, isooctyl acrylate, isononyl acrylate, isoamyl acrylate, n-decyl acrylate, isodecyl acrylate, n-decyl methacrylate, lauryl acrylate, isotriadecyl acrylate, n-octadecyl acrylate, isostearyl acrylate, and n-dodecyl acrylate. Isomers and mixtures of isomers of these monomers may be used.

[0041] Examples of low-Tg (meth)acrylate heteroalkyl ester monomers typically have at least 3, at least 4, or at least 6 carbon atoms, and may have up to 30 or more, up to 20, up to 18, up to 16, up to 12, or up to 10 carbon atoms. Specific examples of (meth)acrylate heteroalkyl esters include 2-ethoxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-methoxyethyl (meth)acrylate, and tetrahydrofuran (meth)acrylate.

[0042] Examples of low Tg aryl-substituted or aryloxy-substituted alkyl acrylates include 2-biphenylhexyl acrylate, benzyl acrylate, 2-phenoxyethyl acrylate, and 2-phenylethyl acrylate.

[0043] Some monomer compositions of (meth)acrylate copolymers may include optional polar monomers. Polar monomers have olefinically unsaturated groups and polar groups, such as acidic groups or their salts, hydroxyl groups, primary amide groups, secondary amide groups, tertiary amide groups, or amino groups. Having polar monomers generally facilitates adhesion of pressure-sensitive adhesives to a variety of substrates. Examples of polar monomers having acidic groups include olefinically unsaturated carboxylic acids, olefinically unsaturated sulfonic acids, olefinically unsaturated phosphonic acids, and mixtures thereof. Examples of such compounds include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, citrate, maleic acid, oleic acid, and (meth)acrylic acid. 2-Carboxyethyl ester, 2-sulfoethyl methacrylate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, vinylphosphonic acid, and mixtures thereof. Due to their availability, the acid monomers are typically acrylic acid or methacrylic acid.

[0044] Examples of polar monomers having hydroxyl groups include: hydroxyalkyl (meth)acrylates (e.g., 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate), hydroxyalkyl (meth)acrylamides (e.g., 2-hydroxyethyl (meth)acrylamides or 3-hydroxypropyl (meth)acrylamides), ethoxylated hydroxyethyl (meth)acrylates (e.g., monomers commercially available under the trade names CD570, CD571, and CD572 from Sartomer (Exton, PA, USA)), and aryloxy-substituted hydroxyalkyl (meth)acrylates (e.g., 2-hydroxy-2-phenoxypropyl (meth)acrylate).

[0045] Examples of polar monomers having a primary amide group include (meth)acrylamide. Examples of polar monomers having a secondary amide group include N-alkyl (meth)acrylamide, such as N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-tert-octyl (meth)acrylamide, or N-octyl (meth)acrylamide.

[0046] Examples of polar monomers having tertiary amide groups include N-vinylcaprolactam, N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, and N,N-dialkyl(meth)acrylamide (such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, and N,N-dibutyl(meth)acrylamide).

[0047] Polar monomers having an amino group include various N,N-dialkylaminoalkyl esters and N,N-dialkylaminoalkyl (meth)acrylamides. Examples include N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylamide, N,N-diethylaminopropyl (meth)acrylamide, and N,N-diethylaminopropyl (meth)acrylamide.

[0048] The monomer composition of (meth)acrylate copolymers may optionally include high Tg monomers. As used herein, the term "high Tg monomer" refers to a monomer having a Tg greater than 30°C, greater than 40°C, or greater than 50°C when homopolymerized (i.e., the homopolymer formed from the monomer has a Tg greater than 30°C, greater than 40°C, or greater than 50°C). Some suitable high Tg monomers... g Monomers having a single (meth)acryloyl group include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, stearyl methacrylate, phenyl acrylate, benzyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, 2-phenoxyethyl methacrylate, N-octyl(meth)acrylamide, and mixtures thereof. Other suitable high-Tg monomers have a single vinyl group that is not a (meth)acryloyl group, such as, for example, various vinyl ethers (e.g., vinyl methyl ether), vinyl esters (e.g., vinyl acetate and vinyl propionate), styrene, substituted styrene (e.g., methyl vinyl ether), styrene, and substituted styrene (e.g., methyl vinyl ether). Vinyl halides, methylstyrene, vinyl halides, and mixtures thereof. Vinyl monomers having the group characteristics of polar monomers are considered polar monomers herein.

[0049] In general, pressure-sensitive adhesives may contain up to 100% by weight (e.g., 100% by weight) of low-Tg monomer units. The weight percentage values ​​are based on the total weight of the monomer units in the polymer material. In some embodiments, the (meth)acrylate polymer contains 40% to 100% by weight of low-Tg monomer units, 0% to 15% by weight of polar monomer units, 0% to 50% by weight of high-Tg monomer units, and 0% to 15% by weight of vinyl monomer units. In some embodiments, the (meth)acrylate polymer contains 60% to 100% by weight of low-Tg monomer units, 0% to 10% by weight of polar monomer units, 0% to 40% by weight of high-Tg monomer units, and 0% to 10% by weight of vinyl monomer units. In some embodiments, the (meth)acrylate polymer comprises 75% to 100% by weight of low Tg monomer units, 0% to 10% by weight of polar monomer units, 0% to 25% by weight of high Tg monomer units and 0% to 5% by weight of vinyl monomer units.

[0050] In some embodiments, adhesive tapes that can be used in the adhesive systems of this disclosure comprise adhesives based on semi-crystalline polymer resins (in some embodiments, pressure-sensitive adhesives), such as polyolefins and polyolefin copolymers (e.g., polymer resins based on monomers having between 2 and 8 carbon atoms, such as low-density polyethylene, high-density polyethylene, polypropylene, and ethylene-propylene copolymers); polyesters and copolyesters; polyamides and copolyamides; fluorinated homopolymers and copolymers; polyepoxides (e.g., polyethylene oxide and polypropylene oxide); polyvinyl alcohol; ionomers (e.g., ethylene-methacrylic acid copolymers neutralized with alkali); and cellulose acetate. Further examples of polymers that can be used as adhesives in adhesive tapes include amorphous polymers such as polyacrylonitrile polyvinyl chloride, thermoplastic polyurethanes, aromatic epoxides, polycarbonates, amorphous polyesters, amorphous polyamides, ABS block copolymers, polyphenylene ether alloys, ionomers (e.g., ethylene-methacrylic acid copolymers neutralized to salt), fluorinated elastomers, and polydimethylsiloxanes.

[0051] In some embodiments, adhesive tapes that can be used in the adhesive systems of this disclosure comprise elastomer-based adhesives (in some embodiments, pressure-sensitive adhesives) of the elastomer being random and block copolymers of polybutadiene, polyisoprene, polychloroprene, styrene, and dienes (e.g., SBR), and ethylene-propylene-diene monomer rubbers. These polymers are typically combined with tackifying resins. Block copolymer adhesive compositions may comprise a first block copolymer comprising at least one rubbery block and at least one glassy block, the rubbery block comprising a first polymeric conjugated diene, its hydrogenated derivative, or a combination thereof, and the glassy block comprising a first polymeric monovinyl aromatic monomer. In some embodiments, the first block copolymer is of formula Q. n -Y multi-arm block copolymer, wherein Q represents an arm of the multi-arm block copolymer; n represents the number of arms and is an integer of at least 3; and Y is a residue of a multifunctional coupling agent. Each arm Q independently has the formula RG, wherein R represents a rubbery block and G represents a glassy block. In some embodiments, the first block copolymer is a multimodal asymmetric star block copolymer. In some embodiments, the adhesive further comprises a second block copolymer. The second block copolymer comprises at least one rubbery block and at least one glassy block. The rubbery block comprises a polymerized second conjugated diene, its hydrogenated derivative, or a combination thereof, and the glassy block comprises a second polymerized monovinyl aromatic monomer. In some embodiments, the second block copolymer is a linear block copolymer. In some embodiments, the pressure-sensitive adhesive based on the block copolymer further comprises a first high-Tg tackifier with a Tg of at least 60°C, wherein the first high-Tg tackifier is compatible with at least one rubbery block. In some embodiments, the block copolymer adhesive composition further comprises a second high-Tg tackifier with a Tg of at least 60°C, wherein the second high-Tg tackifier is compatible with the at least one glassy block.

[0052] In some embodiments, the elastomer-based adhesive is such as those described, for example, in US 9,556,367 (Waid et al.). The adhesive is a pressure-sensitive adhesive and comprises 92 to 99.9 parts of a block copolymer adhesive composition and 0.1 to less than 10 parts of an acrylic adhesive composition. The acrylic adhesive composition comprises 70 to 100 parts of at least one non-tertiary alkyl alcohol acrylate or methacrylate, wherein the non-tertiary alkyl alcohol comprises 4 to 20 carbon atoms; and 0 to 30 parts of a copolymeric reinforcing monomer.

[0053] In some embodiments, adhesive tapes that can be used in the adhesive systems of this disclosure comprise adhesives based on pressure-sensitive adhesives and heat-melt applied adhesives, the adhesives comprising polymers prepared from non-photopolymerizable monomers. Such polymers may be adhesive polymers (i.e., polymers that are inherently adhesives) or polymers that are not inherently adhesives but can form adhesive compositions when blended with components such as plasticizers and / or tackifiers. Specific examples include polyalphaolefins (e.g., polyoctene, polyhexene, and atactic polypropylene), block copolymer-based adhesives, natural and synthetic rubbers, silicone adhesives, ethylene-vinyl acetate blends, and epoxy-containing structural adhesive blends (e.g., epoxy-acrylate and epoxy-polyester blends).

[0054] The adhesives used in the adhesive systems of this disclosure may optionally contain other components such as fillers, antioxidants, viscosity modifiers, pigments (e.g., carbon black, titanium dioxide, or any other suitable pigment), tackifying resins, and fibers. These components may be added to the adhesive to the extent that they do not alter the desired properties of the final product.

[0055] A variety of commercially available adhesive tapes can be used in the adhesive systems disclosed herein. For example, the adhesive system may include adhesive tapes that may be available under the trade name “VHB” from 3M Company, St. Paul, MN. These include the “3M VHB TAPE LSE” series, the “3M VHB TAPE GPH” series, “3M VHB TAPE 4941”, and “3M VHB TAPE 4611”.

[0056] In some embodiments, the adhesive tapes used in the adhesive systems of this disclosure comprise a semi-structural adhesive. The shear storage modulus of the semi-structural adhesive is at least or greater than 0.5 MPa, as measured on a rheometer when an oscillating strain of 1 Hz is applied in the linear viscoelastic region of the adhesive film at 25°C. In some embodiments, the storage modulus of the adhesive is at least 1 MPa or 1.5 MPa. In some embodiments, the storage modulus of the adhesive film of this disclosure is at most 4 MPa, 3.5 MPa, 3 MPa, 2.5 MPa, or 2 MPa. The storage modulus of the bulk adhesive film can be conveniently measured as described in the following examples. In embodiments where the adhesive film is a multilayer film, as described in more detail below, the storage modulus can be determined by nanoindentation based on atomic force microscopy (AFM) at frequencies and temperatures within a rheologically relevant range (0.1 Hz to 100 Hz).

[0057] The semi-structural adhesive exceeds the Dahlquist standard, but provides excellent wetting and adhesion to the substrate in the adhesive system of this disclosure. As shown in the following examples, the semi-structural adhesive can provide lap shear strength values ​​of 2.5 MPa to 3.5 MPa. Therefore, the adhesive film of this disclosure has excellent cohesive strength and can provide lap shear adhesion values ​​much higher than typical PSA.

[0058] In some embodiments, the semi-structural adhesive in the adhesive system of this disclosure comprises a first (meth)acrylate copolymer containing at least 55 wt% of linear or branched alkyl (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer. In some embodiments, the first (meth)acrylate copolymer contains at least 60%, 65%, or 70 wt% of linear or branched alkyl (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer. In some embodiments, the first (meth)acrylate copolymer contains less than 85 wt% or at most 84 wt%, 83 wt%, 82 wt%, 81 wt%, or 80 wt% of linear or branched alkyl (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer. In some embodiments, the semi-structural adhesive in the adhesive system of this disclosure comprises a second (meth)acrylate copolymer containing at least 55 wt%, 60 wt%, 65 wt%, or 70 wt% of linear or branched alkyl (meth)acrylate monomer units based on the weight of the second (meth)acrylate copolymer. In some embodiments, the second (meth)acrylate copolymer comprises less than 85% by weight or up to 84%, 83%, 82%, 81%, or 80% by weight of linear or branched alkyl (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer. In some embodiments, the linear or branched alkyl (meth)acrylate monomer units are C1-C 32 (meth)acrylate monomer unit, C1-C 24 (meth)acrylate monomer units or C1-C 18 (Meth)acrylate monomer units.

[0059] Examples of suitable alkyl (meth)acrylates include those represented by the formula CH2=C(R)COOR', where R is a hydrogen or methyl group, and R' is an alkyl group having 1 to 30, 4 to 30, 6 to 30, 8 to 30, 6 to 24, 6 to 20, 6 to 18, 8 to 24, 8 to 20, or 8 to 20 carbon atoms, and may be straight-chain or branched. Suitable examples of monomers represented by this formula include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and isodecyl acrylate. The monomer units further comprise at least two or at least three structural isomers of secondary alkyl methacrylates represented by Formula III as described above in any of its embodiments. In some embodiments, the first (meth)acrylate copolymer and / or optionally the second (meth)acrylate copolymer comprises at least one of 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, stearyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, isomyristyl (meth)acrylate, isostearyl (meth)acrylate, octadecyl (meth)acrylate, and docosyl (meth)acrylate. Suitable monomer units further comprise at least two or at least three structural isomers of secondary alkyl (meth)acrylates represented by Formula III as described above in any of its embodiments. In some embodiments, the first (meth)acrylate copolymer and / or optionally the second (meth)acrylate copolymer comprises at least one of 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, and isooctyl (meth)acrylate. In some embodiments, the first (meth)acrylate copolymer and / or the second (meth)acrylate copolymer comprises 2-ethylhexyl (meth)acrylate.

[0060] The first (meth)acrylate copolymer, which can be used in the adhesive system of this disclosure, comprises 15% to 40% by weight of (meth)acrylate monomer units. In some embodiments, the first (meth)acrylate copolymer comprises at least 15% by weight, greater than 15% by weight, at least 16% by weight, or at least 17% by weight of (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer. In some embodiments, when present in the semi-structural adhesive, the second (meth)acrylate copolymer comprises greater than 15% to 40% by weight of (meth)acrylate monomer units. In some embodiments, the second (meth)acrylate copolymer comprises at least 15% by weight, at least 16% by weight, or at least 17% by weight of (meth)acrylate monomer units based on the weight of the second (meth)acrylate copolymer. In some embodiments, the first (meth)acrylate copolymer in the semi-structural adhesive comprises, based on the weight of the first (meth)acrylate copolymer, 15.5% to 40% by weight, 16% to 40% by weight, 16% to 35% by weight, 16% to 30% by weight, 16% to 25% by weight, 17% to 25% by weight, 17% to 23% by weight, 17% to 20% by weight, or 17% to 19.5% by weight of (meth)acrylate monomer units. In some embodiments, an optional second (meth)acrylate copolymer in the semi-structural adhesive comprises, based on the weight of the second (meth)acrylate copolymer, 15.5% to 40% by weight, 16% to 40% by weight, 16% to 35% by weight, 16% to 30% by weight, 16% to 25% by weight, 17% to 25% by weight, 17% to 23% by weight, or 17% to 20% by weight of (meth)acrylate monomer units. Examples of (meth)acrylic acid monomer units include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, ethylacrylic acid, crotonic acid, citracic acid, cinnamic acid, ethyl β-carboxyacrylate, and 2-methacryloyloxyethyl succinate. In some embodiments, the (meth)acrylic acid monomer unit is an acrylic acid monomer unit or a methacrylic acid monomer unit. The (meth)acrylic acid monomer unit includes salts of these acids, such as alkali metal salts and ammonium salts.

[0061] In some embodiments, the first (meth)acrylate copolymer that can be used in the adhesive system of this disclosure as a semi-structural adhesive further comprises "high T" g "Monomeric units, these high-T" g Monomers provide the glass transition temperature (T) during polymerization. g The homopolymer is a homopolymer with a temperature of at least 50°C, 60°C, or 70°C (i.e., the T value of the homopolymer formed from this monomer is...). g(At least 50°C, 60°C, or 70°C). In embodiments where the first (meth)acrylate copolymer has 15% by weight of (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer, the first (meth)acrylate copolymer typically also contains at least 5% by weight (in some embodiments, at least 7.5% by weight, 10% by weight, 12.5% ​​by weight, or 15% by weight) of "high T". g "Monomer unit of monomer. T of homopolymer" g Measurements were taken using differential scanning calorimetry, and many are reported in the "Polymer Properties Database" found at polymerdatabase.com. Some suitable high-T... g Monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, isobornyl methacrylate, stearyl methacrylate, phenyl acrylate, benzyl methacrylate, 3,3,5-trimethylcyclohexyl methacrylate, tert-butylcyclohexyl methacrylate, 2-phenoxyethyl methacrylate, N-octyl(meth)acrylamide, tetrahydrofurfuryl methacrylate, and mixtures thereof. Other suitable high-T g Monomers having a single vinyl group that is not a (meth)acryloyl group, such as various vinyl ethers (e.g., vinyl methyl ether), vinyl esters (e.g., vinyl acetate and vinyl propionate), styrene, substituted styrene (e.g. 2-methylstyrene), vinyl halides, and mixtures thereof. In some embodiments, the optional second (meth)acrylate copolymer also comprises high T... g The monomeric unit of the monomer, including any of the aforementioned monomeric units in any weight percentage of the above.

[0062] The first (meth)acrylate copolymer that can be used in the adhesive system of this disclosure comprises, by weight, 0.050% to 5.0% of a crosslinking monomer having more than one (meth)acrylate group, based on the (meth)acrylate copolymer. Suitable crosslinking monomers include diacrylates of glycols, such as ethylene glycol diacrylate, diethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, butane-1,3-dimethyl diacrylate, pentanediol diacrylate, hexanediol diacrylate (including 1,6-hexanediol diacrylate), heptahydrate diacrylate, octanediol diacrylate, nonanediol diacrylate, decanediol diacrylate, and dimethacrylates of any of the aforementioned diacrylates. Other suitable multifunctional monomers include polyacrylates of polyols, such as glyceryl triacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, neopentyl glycol diacrylate, dipentaerythritol pentaacrylate, methacrylates of the aforementioned acrylates, and combinations thereof. Other suitable multifunctional crosslinking monomers include divinylbenzene, allyl methacrylate, diallyl maleate, diallyl phthalate, and combinations thereof. Further suitable multifunctional crosslinking monomers include multifunctional acrylate oligomers comprising two or more acrylate groups. Multifunctional acrylate oligomers may be urethane acrylate oligomers, epoxy acrylate oligomers, polyester acrylates, polyether acrylates, polyacrylate acrylates, methacrylates of any of the aforementioned acrylates, or combinations thereof. Any combination of these crosslinking monomers may be available. In some embodiments, up to 4.0 wt%, 3.0 wt%, 2.0 wt%, or 1.0 wt% of the monomer units in the first (meth)acrylate copolymer are derived from crosslinking monomers. In some embodiments, at least 0.10 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, or 0.70 wt% of the monomer units in the first (meth)acrylate copolymer are derived from crosslinking monomers. When present, the second (meth)acrylate copolymer may contain any of these crosslinking monomer units in any of these amounts, or may not contain any crosslinking monomer units.

[0063] Acrylic polymers can be obtained by nuclear magnetic resonance spectroscopy (NMR spectroscopy). 1 H or 13 Analysis is performed using 12C NMR to identify monomer units in the polymer. Depending on the level of crosslinking in the polymer, solid-state or solution NMR may be useful. For solid-state NMR, the acrylic polymer can be swollen in a suitable solvent for analysis.

[0064] In some embodiments of the semi-structural adhesive in the adhesive system of this disclosure, when present, the T of the first (meth)acrylate copolymer and the second (meth)acrylate copolymer... g Each independently exists within the range of 2°C to 100°C, 2°C to 80°C, 2°C to 60°C, 2°C to 50°C, 2°C to 45°C, 5°C to 45°C, 5°C to 40°C, 5°C to 35°C, or 10°C to 30°C. In some embodiments, when present, the T of the first (meth)acrylate copolymer and the second (meth)acrylate copolymer... g Each is independently defined as not exceeding 100℃, not exceeding 80℃, not exceeding 60℃, not exceeding 50℃, not exceeding 45℃, or even not exceeding 40℃.

[0065] In some embodiments, the thickness of the semi-structural adhesive in the adhesive system of this disclosure is at least 0.3 mm. In some embodiments, the thickness of the semi-structural adhesive is in the range of 300 μm to 6000 μm, 300 μm to 4000 μm, 300 μm to 2000 μm, 500 μm to 2000 μm, 800 μm to 1500 μm, or 600 μm to 1300 μm.

[0066] In some embodiments of the semi-structural adhesive tape in the adhesive system disclosed herein, the semi-structural adhesive comprises 65 wt% to 99 wt%, 70 wt% to 95 wt%, 75 wt% to 95 wt%, 75 wt% to 90 wt%, or even 75 wt% to 85 wt% of a first (meth)acrylate copolymer, wherein the weight percentages are based on the total weight of the semi-structural adhesive. In some embodiments, the semi-structural adhesive comprises 1 wt% to 35 wt%, 1 wt% to 30 wt%, 2 wt% to 25 wt%, 3 wt% to 25 wt%, 3 wt% to 20 wt%, 4 wt% to 20 wt%, or even 4 wt% to 15 wt% of a second (meth)acrylate copolymer, wherein the weight percentages are based on the total weight of the semi-structural adhesive.

[0067] In some embodiments, the semi-structural adhesive in the adhesive system of this disclosure comprises no more than 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, or 0 wt% of an additional (meth)acrylate copolymer having 0.1 wt% to 15 wt% (in some embodiments, 0.1 wt% to 12 wt%, 0.1 wt% to 11 wt%, 0.1 wt% to 10 wt%, 0.2 wt% to 10 wt%, 0.2 wt% to 9 wt%, 0.2 wt% to 8 wt%, 0.3 wt% to 8 wt%, 0.5 wt% to 8 wt%, 0.5 wt% to 6 wt%, 1 wt% to 6 wt%, or 1 wt% to 5 wt%) of (meth)acrylate monomer units based on the weight of the additional (meth)acrylate copolymer. Such additional (meth)acrylate copolymers in the adhesive film of this disclosure tend to reduce the Tt of the semi-structural adhesive. g And / or storage modulus, and will also tend to reduce the cohesive strength of semi-structural adhesives.

[0068] The first (meth)acrylate copolymer and the second (meth)acrylate, which can be used in some embodiments of the semi-structural adhesives in the adhesive systems of this disclosure, the (meth)acrylate copolymers that can be used in the pressure-sensitive adhesives in the adhesive systems of this disclosure, and the polyacrylates that can be used in some embodiments of the primer compositions, can each be prepared by any conventional free radical polymerization method, including solution, radiation, bulk, dispersion, emulsion, solvent-free, and suspension methods. The resulting copolymers can be random copolymers or block copolymers. In some embodiments, the first (meth)acrylate copolymer is prepared as a solution or slurry copolymer composition.

[0069] Typical solution polymerization is carried out by adding monomers, a suitable solvent, and optionally a chain transfer agent to a reaction vessel; adding a free radical initiator; purging with nitrogen; and maintaining the reaction vessel at an elevated temperature (typically in the range of about 40°C to 100°C) until the reaction is complete, typically for about 1 hour to 24 hours, depending on batch size and temperature. Examples of solvents include methanol, tetrahydrofuran, ethanol, isopropanol, tert-butanol, acetone, methyl ethyl ketone, methyl acetate, ethyl acetate, toluene, xylene, and ethylene glycol alkyl ethers. These solvents can be used alone or as mixtures thereof. In typical thermal polymerization, the monomer mixture is subjected to heat in the presence of a thermal polymerization initiator (i.e., a thermal initiator). Examples of suitable thermal initiators are those available from DuPont under the trade name "VAZO".

[0070] Slurry polymer technology involves partially polymerizing monomers to produce a slurry polymer comprising a (meth)acrylate copolymer and unpolymerized monomers. The slurry polymer composition is polymerized to a usable coating viscosity, allowing it to be coated onto a substrate (such as a backing) and further polymerized. In some embodiments, polymerization is carried out in the absence of a solvent (such as ethyl acetate, toluene, or tetrahydrofuran) that does not react with the functional groups of the slurry polymer components.

[0071] In some embodiments, the coatable slurry polymer for adhesive tapes that can be used in the adhesive systems of this disclosure is prepared by photo-initiated free radical polymerization. Polymerization can be carried out to achieve a coatable viscosity such that the monomer-to-polymer conversion is at most about 10%. Polymerization can be achieved by exposing the slurry polymer composition to light energy in the presence of a photoinitiator. When the desired conversion and viscosity have been achieved, polymerization can be terminated by removing the light source and by quenching the propagating free radicals by bubbling air (oxygen) into the solution. In cases where polymerization is initiated, for example, using ionizing radiation, an energy-activated initiator may not be required.

[0072] In some embodiments, the free radical photoinitiator used to manufacture the adhesive tape in the adhesive system of this disclosure is a type I (cleavage-type) photoinitiator. Cleavage-type photoinitiators include acetophenone, α-aminoalkylphenyl ketone, benzoyl ether, benzoyl oxime, acyl (e.g., benzoyl)phosphine oxide, acyl (e.g., benzoyl) phosphonates, and mixtures thereof. Examples of available benzoyl ethers include benzoyl methyl ether and benzoyl butyl ether. Examples of suitable acetophenone compounds include 4-diethylaminoacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-dimethylamino-4'-morpholinobutyroylbenzene, 2-hydroxy-2-methyl-1-phenylprop-1-one, 2,2-dimethoxyacetophenone, and 2,2-dimethoxy-1,2-diphenylethyl-1-one. Examples of suitable acylphosphine oxides, acylphosphonates, and acylphosphonate compounds include bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethylphenyl(2,4,6-trimethylbenzoyl)phosphonate, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, dimethylneoptiylphosphonate, and poly(oxy-1,2-ethanediyl), α,α',α''-1,2,3-propanetriyltri[ω-[[phenyl(2,4,6-trimethylbenzoyl)phosphineyl]oxy]. Additionally, suitable photoinitiators include substituted... - Ketools, such as 2-methyl-2-hydroxyphenylacetone; aromatic sulfonyl chlorides, such as 2-naphthalene-sulfonyl chloride; and photooximes, such as 1-phenyl-1,2-propanedione-2-(O-ethoxy-carbonyl)oxime. Many photoinitiators are available, for example, under the trade name "IRGACURE" from BASF, Vandalia, Illinois, and under the trade names "OMNIRAD" and "ESACURE" from IGMresins, Waalwijk, Netherlands. Two or more of these photoinitiators can also be used in any combination. Additional photoinitiators can be added to the mixture to be coated after the copolymer has been formed (i.e., photoinitiators can be added to the slurry polymer mixture).

[0073] The degree of conversion (from monomer to copolymer) can be monitored by measuring the refractive index of the polymer mixture during irradiation.

[0074] If desired, a chain transfer agent may be added to the monomer mixture to prepare any of the acrylic copolymers disclosed herein (e.g., polyacrylates in primers, pressure-sensitive adhesives in adhesive tapes, and semi-structural adhesives in adhesive tapes). Examples of usable chain transfer agents include carbon tetrabromide, alcohols, thiols, and mixtures thereof. In some embodiments, the chain transfer agent comprises at least one of isooctyl mercaptoacetate or carbon tetrabromide.

[0075] The adhesive in the adhesive tape of the adhesive system disclosed herein (e.g., pressure-sensitive adhesive or semi-structural adhesive) may contain a tackifying resin, particularly a hydrogenated hydrocarbon tackifier, as an optional component. Examples of hydrogenated hydrocarbon tackifiers include C9 and C5 hydrogenated hydrocarbon tackifiers. Examples of C9 hydrogenated hydrocarbon thickeners include those sold under the following trade names: “REGALITE S-5100,” “REGALITE R-7100,” “REGALITE R-9100,” “REGALITE R-1125,” “REGALITE S-7125,” “REGALITE S-1100,” “REGALITE R-1090,” “REGALREZ 6108,” “REGALREZ 1085,” “REGALREZ 1094,” “REGALREZ 1126,” “REGALREZ 1139,” and “REGALREZ 3103”, sold by Eastman Chemical Co., Middelburg, Netherlands; “PICCOTAC” and “EASTOTAC”, sold by Eastman Chemical Co., Chicago, Illinois; and Arakawa Chemical Co., Chicago, Illinois. The following are listed as “ARKON P-140,” “ARKON P-125,” “ARKON P-115,” “ARKON P-100,” “ARKON P-90,” “ARKON M-135,” “ARKON M-115,” “ARKON M-100,” and “ARKON M-90” sold by Inc. (Chicago, IL); and the “ESCOREZ 5000 series” sold by ExxonMobil Corp., Irving, TX. In some embodiments, the tackifier is a partially hydrogenated C9 hydrogenated tackifier, a fully hydrogenated C9 hydrogenated tackifier, or a combination thereof. In some embodiments, the adhesives that can be used in the adhesive systems of this disclosure are substantially free of tackifying resins, particularly hydrocarbon tackifying resins.

[0076] If desired, other additives may be added to the adhesive tape of the adhesive system disclosed herein (e.g., to pressure-sensitive adhesives or semi-structural adhesives). Examples include homogenizers, UV absorbers, hindered amine light stabilizers (HALS), oxygen inhibitors, wetting agents, rheology modifiers, defoamers, biocides, flame retardants, and dyes. All such additives and their uses are known to those skilled in the art and may be used provided they do not adversely affect the adhesive properties.

[0077] In some advantageous aspects, the adhesive (e.g., a semi-structural adhesive or a pressure-sensitive adhesive) used in the adhesive systems of this disclosure comprises a filler material, specifically, a particulate filler material. In some embodiments, the optional filler material used herein includes at least one of polymer microspheres, hollow ceramic microspheres, or glass bubbles.

[0078] In some embodiments, the adhesive (e.g., a semi-structural adhesive or a pressure-sensitive adhesive) of the adhesive tape that can be used in the adhesive system of this disclosure is in the form of foam. The foam includes voids, which may be open-cell or closed-cell. In some embodiments, the voids are present in the foam in an amount of at least 5% by volume, from 10% to 55% by volume, from 10% to 45% by volume, from 15% to 45% by volume, or from 20% to 45% by volume. The density of the adhesive film in foam form is typically in the range of 0.45 g / cm³ to 1.5 g / cm³, 0.45 g / cm³ to 1.10 g / cm³, 0.50 g / cm³ to 0.95 g / cm³, 0.60 g / cm³ to 0.95 g / cm³, or 0.70 g / cm³ to 0.95 g / cm³.

[0079] In some embodiments, the thickness of the adhesive foam used in the adhesive tape of the adhesive system disclosed herein is in the range of 100 micrometers to 6000 micrometers, 200 micrometers to 4000 micrometers, 500 micrometers to 2000 micrometers, or 800 micrometers to 1500 micrometers. In some embodiments, the thickness of the adhesive foam is at least 300 micrometers. It will be apparent to those skilled in the art that, according to this specification, the thickness of the foamed adhesive will depend on the intended application.

[0080] The voids or pores in the foam can be created in any manner known in the art, including the use of gases or foaming agents and / or the inclusion of hollow particles in the composition for use with the foam. For example, according to a method of producing foam described in US 4,415,615 (Esmay et al.), acrylic foam can be obtained by foaming a composition containing acrylate monomers and optionally comonomers, coating the foamed composition onto a backing, and polymerizing the foamed composition. It is also possible to coat an unfoamed composition of acrylate monomers and optionally comonomers onto a backing and then simultaneously foam and polymerize the composition. Foaming of the composition can be achieved by optionally agitating a gas into the polymerizable composition in the presence of a surfactant (e.g., a hydrocarbon or fluorinated surfactant) or surface-modified nanoparticles to stabilize the foam. Inert gases (such as nitrogen, argon, and carbon dioxide) can be useful, especially when the polymerization is photoinitiated.

[0081] In some embodiments, the adhesive foam of the adhesive tape, which can be used in the adhesive system of this disclosure, is incorporated with hollow fillers, such as hollow polymer particles, hollow glass microspheres, and hollow ceramic microspheres. Hollow polymer microspheres include elastomer particles that can be obtained, for example, from Akzo Nobel, Amsterdam, The Netherlands, under the trade name “EXPANCEL.” Examples of hollow ceramic microspheres include alumina / silica microspheres (“FILLITE”, Pluress-Stauffer International) with a particle size in the range of 5 micrometers to 300 micrometers and a specific gravity of 0.7; alumina silicate microspheres (“Z-LIGHT”) with a specific gravity of about 0.45 to about 0.7; calcium carbonate-coated polyvinylidene copolymer microspheres (“DUALITE 6001AE”, Pierce & Stevens Corp.) with a specific gravity of 0.13; and those from 3M Company, Saint Paul, Minnesota. Minnesota sells glass bubbles in 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 of “3M GLASS BUBBLES”, as well as any HGS series of “3M GLASS BUBBLES”. Foams containing hollow microspheres are referred to as composite foams. The foaming adhesive may also include hydrocarbon elastomers as described in U.S. Patent No. 5,024,880 (Vesley et al.).

[0082] The adhesive for adhesive tapes that can be used in the adhesive system of this disclosure can be prepared by simply blending a (meth)acrylate copolymer, optionally with optional components such as fillers and tackifying resins. Several conventional methods, such as melt blending, solvent blending, or any suitable physical means, can be used to blend the copolymer.

[0083] Physical mixing apparatuses providing dispersion mixing, partition mixing, or a combination of dispersion and partition mixing can be used to prepare homogeneous blends. Both batch and continuous physical blending methods can be used. Examples of batch methods include BRABENDER (e.g., the BRAB ENDER PREP CENTER available from CW Brabender Instruments, Inc., South Hackensack, NJ) or BANBURY internal mixing and roller milling (using equipment available from FARREL COMPANY, Ansonia, CT). Examples of continuous methods include single-screw extrusion, twin-screw extrusion, disc extrusion, reciprocating single-screw extrusion, and pin-barrel single-screw extrusion. Continuous methods may include the use of dispensing elements, such as cavity transfer elements (e.g., CTM available from RAPRA Technology, Ltd., Shrewsbury, England) and pin mixing elements, electrostatic mixing elements, and dispersing elements (e.g., MADDOCK mixing elements or SAXTON mixing elements as described in “Mixing in Single-Screw Extruders”, “Mixing in Polymer Processing”, edited by Chris Rauwendaal (Marcel Dekker Inc., New York (1991), pp. 129, 176-177 and 185-186).

[0084] In some embodiments, the semi-structural adhesive of the adhesive tape that can be used in the adhesive system of this disclosure comprises 65% to 98% by weight, 70% to 95% by weight, 75% to 95% by weight, 75% to 90% by weight, or 75% to 85% by weight of a first (meth)acrylate copolymer; 0% to 35% by weight, 1% to 35% by weight, 1% to 30% by weight, 2% to 25% by weight, 3% to 25% by weight, 3% to 20% by weight, 4% to 20% by weight, or 4% to 15% by weight of a second (meth)acrylate copolymer; and optionally, 2% to 15% by weight, 2% to 14% by weight, or 2% to 12% by weight of a filler material comprising at least one of polymeric microspheres and glass bubbles, wherein the weight percentages are based on the total weight of the semi-structural adhesive.

[0085] In some embodiments, the second (meth)acrylate copolymer used in the adhesive system of this disclosure is prepared using a substantially solvent-free free radical polymerization method, particularly a substantially solvent-free thermal free radical polymerization method. In some embodiments, the second (meth)acrylate copolymer used herein is prepared by a substantially adiabatic polymerization method. The degree of conversion (conversion of monomer to copolymer) can be monitored during polymerization by measuring the refractive index of the polymer mixture.

[0086] In some embodiments, the second (meth)acrylate copolymer, which can be used in the adhesive system of this disclosure for use in semi-structural adhesive tapes, is obtained as a prepolymer composition having a polymer conversion rate greater than 10%, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, or greater than 45%, and in some embodiments having a polymer conversion rate between 10% and 60%, between 20% and 55%, between 30% and 50%, or even between 35% and 50%.

[0087] According to one aspect of this disclosure, a semi-structural adhesive for adhesive tapes that can be used in the adhesive system of this disclosure can be prepared by incorporating a second (meth)acrylate copolymer into a curable precursor composition of a first (meth)acrylate copolymer, the curable precursor composition comprising linear or branched alkyl (meth)acrylate monomers, (meth)acrylate monomers, crosslinking monomers, optional polymerization initiators, and optional particulate fillers, thereby forming a curable precursor composition for an adhesive film. Then, in a second step, the first (meth)acrylate copolymer is formed in situ by polymerizing the linear or branched alkyl (meth)acrylate monomers, (meth)acrylate monomers, and crosslinking monomers in the presence of the second (meth)acrylate copolymer to form the first (meth)acrylate copolymer. In some embodiments, the second (meth)acrylate copolymer is diluted into the curable precursor composition of the first (meth)acrylate copolymer and mixed by shaking. In some embodiments, the polymerization of linear or branched alkyl methacrylate monomers, methacrylate monomers, and crosslinking monomers to form the first (meth)acrylate copolymer in the presence of the second (meth)acrylate copolymer is carried out using photochemical radiation.

[0088] According to another aspect, the adhesive used in the adhesive system of this disclosure is a multilayer adhesive assembly comprising an adhesive in the form of a first adhesive layer (in some embodiments, a first adhesive foam layer) as described above, the adhesive further comprising a second adhesive layer adjacent to the first adhesive film layer. The first and second adhesive layers may be pressure-sensitive adhesives as described above, semi-structural adhesives as described above, or a combination of both.

[0089] This type of multilayer adhesive assembly, and especially double-layer or skin-core-skin foam tape assemblies, is advantageous compared to single-layer adhesives because adhesion (fast adhesion) can be regulated by the formulation of the second adhesive layer (often also called the skin layer), while other characteristics / requirements of the overall assembly, such as application issues, deformation issues, and energy distribution, can be addressed by the appropriate formulation of the first adhesive film layer (often also called the core layer).

[0090] In some embodiments, the multilayer adhesive assembly as described herein is in the form of a skin / core multilayer adhesive assembly, wherein the first layer is a semi-structural adhesive as described above in any of its embodiments, in some embodiments in the form of foam and is the core layer of the multilayer adhesive assembly, and the second adhesive layer is the skin layer of the multilayer adhesive assembly.

[0091] In some embodiments, the multilayer adhesive assembly as described herein is in the form of a multilayer adhesive assembly including a third adhesive layer, thereby forming, for example, a three-layer multilayer adhesive assembly. In some embodiments, the third adhesive layer is adjacent to the first adhesive layer on one side, opposite to the side of the first adhesive layer adjacent to the second adhesive layer. In some embodiments, the first adhesive layer, the second adhesive layer, and the third adhesive layer are stacked.

[0092] In some embodiments, the multilayer adhesive assembly is in the form of a skin / core / skin multilayer adhesive assembly, wherein the first adhesive layer is a semi-structural adhesive in the form of foam as described above in any of its embodiments and is the core layer of the multilayer adhesive assembly, the second adhesive layer is the first skin layer of the multilayer adhesive assembly, and the third adhesive layer is the second skin layer of the multilayer adhesive assembly.

[0093] The second and / or third adhesive layers may have any composition known in the art. Therefore, there are no particular limitations on the composition of these layers used in the multilayer adhesive assembly of this disclosure.

[0094] In some embodiments, the second adhesive layer and / or the third adhesive layer comprises a polymer matrix material independently selected from the group consisting of: polyacrylate, polyurethane, polyolefin, polyamine, polyamide, polyester, polyether, polyisobutylene, polystyrene, polyethylene, polyvinylpyrrolidone, natural rubber, synthetic rubber, and any combination, copolymer, or mixture thereof. In some embodiments, the second adhesive layer and / or the third adhesive layer comprises a polymer matrix material selected from the group consisting of: polyacrylate, polyurethane, and any combination, copolymer, or mixture thereof. In some embodiments, the second adhesive layer and / or the third adhesive layer comprises a polymer matrix material selected from the group consisting of: polyacrylate, and any combination, copolymer, or mixture thereof.

[0095] In some embodiments, the second and third adhesive layers independently comprise a polyacrylate polymer matrix material as described above for pressure-sensitive adhesive (meth)acrylate copolymers or semi-structural adhesive compositions. In some embodiments of the multilayer adhesive assembly of this disclosure, the second and / or third adhesive layers have the same or similar (co)polymer composition as described above for the semi-structural adhesives of this disclosure. In some embodiments of these embodiments, the second and / or third adhesive layers are free of fillers and / or non-foamed.

[0096] According to some aspects of the multilayer adhesive assembly disclosed herein, the second adhesive layer and / or the third adhesive layer further comprise a tackifying resin, particularly a hydrocarbon tackifying resin. The tackifying resin may be any of the aforementioned tackifying resins. Advantageously, the tackifying resin is selected from the group consisting of: C5-based hydrocarbon resins, C9-based hydrocarbon resins, C5 / C9-based hydrocarbon resins, and any combination or mixture or hydrogenated variant thereof.

[0097] In some embodiments of the multilayer adhesive assembly disclosed herein, the polymerizable material for producing the second adhesive layer and / or the third adhesive layer comprises 50% to 99.5% or 60% to 95% by weight of a linear or branched alkyl (meth)acrylate as the first / major monomer, wherein the major monomer in some embodiments is selected from the group consisting of: isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-propylheptyl (meth)acrylate, and butyl acrylate; optionally, 1.0% to 50% by weight, 3.0% to 40% by weight, and 5% by weight. 0.0 wt% to 35 wt% or 10 wt% to 30 wt% of high Tg monomers as described above in any of its embodiments; optionally, 0.1 wt% to 15 wt%, 0.5 wt% to 15 wt%, 1.0 wt% to 10 wt%, 2.0 wt% to 8.0 wt%, 2.5 wt% to 6.0 wt% or 3.0 wt% to 6.0 wt% of polar monomers, such as polar (meth)acrylates; and optionally, tackifying resins, wherein the weight percentages are based on the total weight of polymerizable materials used to produce the second adhesive layer and / or the third adhesive layer.

[0098] According to an advantageous aspect of the multilayer adhesive assembly disclosed herein, the second adhesive layer and / or the third adhesive layer comprises a polymer matrix material that further comprises a chlorinated polyolefin (co)polymer. Incorporating the chlorinated polyolefin (co)polymer into the curable precursor of the second adhesive layer and / or the third adhesive layer improves the stability of the resulting adhesive layer, particularly during thermal bond aging and thermal / wet bond aging on low surface energy (LSE) substrates. In some embodiments, the second adhesive layer and / or the third adhesive layer does not contain a chlorinated polyolefin (co)polymer.

[0099] Examples of suitable chlorinated polyolefin (co)polymers used herein include those sold under the following trade names: “CPO 343-1” sold by Eastman Chemical Co.; “13-LP”, “15-LP”, “16-LP”, and “17-LP” sold by Toyo Kasei Kogyo Co. Ltd.; “HYPALON CP 827B”, “HYPALON CP 163”, and “HYPALON CP 183” sold by DuPont Co.; and “TYRIN CPE 4211P”, “TYRIN CPE 6323A”, and “TYRIN CPE 3615P” sold by Dow Chemical Company. Suitable chlorinated polyolefins include chlorinated polypropylene, chlorinated polyethylene, chlorinated vinyl / vinyl acetate copolymers, and any combination, mixture, or copolymer thereof. In some embodiments, the chlorinated polyolefin (co)polymer is chlorinated polypropylene.

[0100] In some embodiments, the multilayer adhesive assembly, as described above in any of the embodiments of the multilayer adhesive assembly, is obtained via a wet-on-wet coating process step. Exemplary "wet-in-wet" manufacturing processes used herein are described, for example, in WO-A1-2011094385 (Hitschmann et al.) or EP-A1-0259094 (Zimmerman et al.). In some embodiments, the method for manufacturing the multilayer adhesive assembly includes a wet-on-wet coating process step.

[0101] According to another aspect, this disclosure discloses a method for manufacturing a multilayer adhesive assembly as described above in any embodiment of the multilayer adhesive assembly, wherein the method includes stacking a (liquid) precursor of a first adhesive layer, a (liquid) precursor of a second adhesive layer, and optionally a (liquid) precursor of a third adhesive layer to form a curable precursor of the multilayer adhesive assembly; and in some embodiments, curing the curable precursor of the multilayer adhesive assembly with photochemical radiation.

[0102] In some embodiments of the method for manufacturing a multilayer adhesive assembly, the (lower) layer of the curable (liquid) precursor of the second adhesive layer is each covered by an adjacent (upper) layer of the curable liquid precursor of the first adhesive layer, substantially not exposing the (lower) layer of the curable (liquid) precursor of the second adhesive layer.

[0103] In some embodiments, the multilayer adhesive assembly is manufactured by a continuous and self-metering method for manufacturing the multilayer adhesive assembly. In some of these embodiments, the method includes providing two or more coating blades, which are independently biased from the substrate to form gaps normal to the surface of the substrate; moving the substrate relative to the coating blades in a downstream direction; and providing a curable (liquid) precursor for a first adhesive layer, a curable (liquid) precursor for a second adhesive layer, and optionally a curable (liquid) precursor for a third adhesive layer to the upstream side of the coating blades, thereby coating two or more curable liquid precursors as overlays onto the substrate through the respective gaps. Based on this disclosure and the disclosure of U.S. Patent Application Publication No. 2013 / 0004694 (Hitschmann et al.), the proper setup and configuration of the coating equipment, coating blades, and coating stations for practicing the continuous and self-metering method for manufacturing multilayer adhesive assemblies as described above, particularly for this specific aspect of the method for manufacturing multilayer adhesive assemblies, is entirely within the capabilities of those skilled in the art.

[0104] In some embodiments of the method for manufacturing a multilayer adhesive assembly, a first adhesive layer, a second adhesive layer, and optionally a third adhesive layer are prepared separately and subsequently laminated together. In other embodiments of the method for manufacturing a multilayer adhesive assembly, the method includes a (co)extrusion processing step. In other embodiments of the method for manufacturing a multilayer adhesive assembly, as described in U.S. Patent No. 4,818,610 (Zimmerman et al.), the method includes sequentially coating a liquid composition, each comprising at least one photopolymerizable monomer, onto a substrate. A liner may be attached to the top layer, and the multiple stacked layers may be cured by exposing them to light to provide an adhesive tape.

[0105] An adhesive film, including the pressure-sensitive adhesive or semi-structural adhesive described in any of the embodiments above, can be conveniently applied to or between liner pads that can be treated with a release coating. Any suitable material for the liner pads and the release coating can be used. In some embodiments, the adhesive film can be applied to the liner pads that have different release properties on each surface and optionally wound into rolls.

[0106] As described above in any of its embodiments, the primer and adhesive tape of the adhesive system disclosed herein can be applied to a variety of substrates. The substrate can be flexible or inflexible and is formed of polymeric materials, glass or ceramic materials, metals, or combinations thereof. Suitable polymeric substrates include polymeric films, such as those prepared from materials including: polypropylene, polyethylene, polyvinyl chloride, polyester (polyethylene terephthalate or polyethylene naphthalate), polycarbonate, poly(methyl methacrylate) (PMMA), cellulose acetate, cellulose triacetate, and ethyl cellulose. Foam substrates can be used. Examples of other substrates include metals such as stainless steel, polymeric materials coated with metals or metal oxides, and glass coated with metals or metal oxides.

[0107] In the context of this disclosure, the term "low surface energy substrate" refers to substrates having a surface energy of less than 34 dynes / cm. The term "medium surface energy substrate" means substrates with a surface energy between 34 and 70 dynes / cm, typically between 34 and 60 dynes / cm, and more typically between 34 and 50 dynes / cm. The term "high surface energy substrate" means substrates with a surface energy greater than 350 dynes / cm, typically greater than 400 dynes / cm, and more typically between 400 and 1100 dynes / cm. Surface energy is typically determined by contact angle measurements, such as those described in ASTM D7490-08.

[0108] The adhesive films and multilayer adhesive assemblies disclosed herein can be used to form strong adhesion to low surface energy (LSE) substrates. Such materials include polypropylene, polyethylene (e.g., high-density polyethylene or HDPE), blends of polypropylene (e.g., PP / EPDM, TPO), or even some varnish-coated surfaces. Other substrates may also exhibit low surface energy properties due to the presence of residues (such as oily residues) or films (such as paint) on the substrate surface.

[0109] The adhesive films and multilayer adhesive assemblies disclosed herein can also be used to bond to medium surface energy (MSE) substrates, such as, for example, polyamide 6 (PA6), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) / ABS blends, PC, PVC, polyurethane (PUR), thermoplastic elastomers (TPE), polyoxymethylene (POM) polystyrene, poly(methyl methacrylate) (PMMA), some clear coat surfaces (particularly for clear coats on vehicles such as vehicles or coated surfaces for industrial applications), and composites such as fiber-reinforced plastics.

[0110] The adhesive films and multilayer adhesive assemblies disclosed herein can also be used to bond high surface energy (HSE) substrates, such as, for example, ceramics, glass, and metals.

[0111] Therefore, this disclosure further relates to the use of the adhesive system described above for bonding to low surface energy substrates, medium surface energy substrates and / or high surface energy substrates.

[0112] The adhesive system disclosed herein can be used in any articles conventionally known to use such components, such as labels, tapes, signs, covers, markings, display parts, and touch panels.

[0113] A method of manufacturing an adhesive article may include applying a primer composition to a surface of a first substrate, and then applying an adhesive tape to the primer composition on the surface of the first substrate. Before applying the adhesive tape, the primer composition may be allowed to stand on the substrate for at least 5 minutes, 10 minutes, 15 minutes, 30 minutes, or 60 minutes. In some embodiments, the adhesive tape is a double-sided tape. In some embodiments, the method further includes applying a primer composition to a surface of a second substrate, and applying the adhesive tape to the primer composition on the surface of the second substrate, thereby adhering the first substrate to the second substrate. In some embodiments, the adhesive tape is a pressure-sensitive adhesive. In some embodiments, the adhesive tape is a semi-structural tape.

[0114] The primer composition and adhesive tape in the adhesive system disclosed herein can be coated / applied to the substrate using any conventional coating technique modified to suit a particular substrate. For example, the primer composition can be applied / coated to a variety of solid substrates by methods such as roller coating, flow coating, dip coating, spin coating, spray coating, blade coating, and mold coating. These various coating methods allow the primer composition to be placed on the substrate at variable thicknesses, thereby allowing for a wider range of applications for the adhesive system.

[0115] The substrates to which the primer compositions and adhesive tapes of this disclosure can be applied are selected depending on the specific application. For example, the primer compositions and adhesive tapes can be applied to sheet products (e.g., decorative graphics and reflective products), labelstock, and backing tapes. Alternatively, the adhesive films and multilayer adhesive assemblies of this disclosure can be applied directly to other substrates, such as metal panels (e.g., automotive panels) or glass windows, allowing another substrate or object to be attached to the panel or window. Therefore, the adhesive films and multilayer adhesive assemblies of this disclosure can be specifically used in the automotive manufacturing industry (e.g., for attaching exterior trim or for weatherstripping), the construction industry, or the solar panel construction industry.

[0116] Therefore, this disclosure further relates to the use of the adhesive system of this disclosure in industrial applications, particularly in construction applications, motor vehicle applications (e.g., including specialized vehicles such as trucks, trains and buses), appliances, overlays and displays.

[0117] As described above, when applied without the use of heat or radiation, the adhesive tape typically adheres to the substrate surface of the primer. The adhesive tape typically adheres to the substrate surface of the primer without forming covalent bonds. Advantageously, the adhesive tape does not require crosslinking agents or reactive chemicals to enhance adhesive strength. Therefore, the adhesive tape typically does not contain thermal crosslinking additives such as polyfunctional aziridine, isocyanates, or epoxides, or chemical crosslinking agents such as peroxides. Furthermore, the adhesive tape typically does not contain photochemical crosslinking additives that are activated after application to the substrate. In some embodiments, the adhesive tape of this disclosure does not contain polyfunctional aziridine, polyfunctional isocyanates, polyfunctional epoxides, benzophenone, triazine, polyfunctional carboxylic acid esters, oxetane, or oxazoline.

[0118] As illustrated in the following examples, the adhesive system of this disclosure provides excellent adhesion to a variety of substrates, resulting in a peel adhesion of at least 50 N / cm and an lap shear adhesion of greater than 2.5 mPA in the semi-structural tape embodiment. In some embodiments, the use of methyl methacrylate instead of isobornyl acrylate (another high Tg monomer) in the primer composition improves adhesion, particularly to MSE or LSE substrates. See, for example, the comparison of Example 1 with Illustrative Example 3 and the comparison of Example 4 with Illustrative Example 5. In some embodiments, the inclusion of a monomer containing a carboxylic acid in the primer composition improves lap shear adhesion, particularly to metals (e.g., aluminum).

[0119] Some implementation schemes disclosed herein

[0120] In a first embodiment, the present disclosure provides a primer composition comprising a polyacrylate dissolved in an organic solvent, the polyacrylate comprising, based on the total weight of monomer units in the polyacrylate: at least 20% by weight of methyl methacrylate units, at least 15% by weight of monomer units comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, at least 15% by weight of acrylic monomer units comprising an alkyl group having at least four carbon atoms, and an amount of 0.5% to 10% by weight of acrylic monomer units comprising a carboxylic acid group. In a second embodiment, this disclosure provides a primer composition according to the first embodiment, wherein the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide includes at least one of the following: 2-(N,N-dimethylaminoethyl) (meth)acrylate, 2-(N,N-diethylaminoethyl) (meth)acrylate, 2-(tert-butylaminoethyl) (meth)acrylate, 2-(N,N-dimethylaminoethyl)(meth)acrylamide, 2-(N,N-diethylaminoethyl)(meth)acrylamide, 2-(tert-butylaminoethyl)(meth)acrylamide, N-(meth)acryloylpiperidine, N-vinylcaprolactam, and N-vinyl-2-pyrrolidone. In a third embodiment, this disclosure provides a primer composition according to the first or second embodiment, wherein the methyl methacrylate unit, the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, the acrylic monomer unit comprising an alkyl group having at least four carbon atoms, and the acrylic monomer unit comprising a carboxylic acid group collectively comprise at least 95% by weight of the monomer units in the polyacrylate. In a fourth embodiment, this disclosure provides a primer composition according to any one of the first to third embodiments, wherein, based on the total weight of the monomer units in the polyacrylate, the content of the methyl methacrylate unit is 25% to 65% by weight, the content of the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide is 15% to 40% by weight, the content of the acrylic monomer unit comprising an alkyl group having at least four carbon atoms is 15% to 40% by weight, and the content of the acrylic monomer unit comprising a carboxylic acid group is 2% to 7% by weight. In a fifth embodiment, this disclosure provides a primer composition according to any one of the first to fourth embodiments, the primer composition further comprising at least one of a moisture stabilizer or an adhesion promoter. In a sixth embodiment, this disclosure provides a primer composition according to the fifth embodiment, wherein the adhesion promoter is a silane or titanate chelate. In a seventh embodiment, this disclosure provides a primer composition according to any one of the first to sixth embodiments, wherein, excluding the organic solvent, the polyacrylate comprises at least 95% by weight of the primer composition.In an eighth embodiment, this disclosure provides a primer composition according to any one of the first to seventh embodiments, wherein the primer composition also does not contain polyamide. In a ninth embodiment, this disclosure provides a primer composition according to any one of the first to sixth embodiments, wherein the primer composition further contains polyamide. In a tenth embodiment, this disclosure provides a primer composition according to the ninth embodiment.

[0121] In an eleventh embodiment, this disclosure provides a primer composition according to any one of the first to tenth embodiments, wherein the solvent comprises at least one of dimethyl carbonate, propylene carbonate, an alcohol, a polyol, a polyol ether, a polyol ether ester, a diester, limonene, a methylsiloxane, or a ketone or ester each having up to six carbon atoms. In a twelfth embodiment, this disclosure provides a primer composition according to the eleventh embodiment, wherein the solvent comprises at least one of dimethyl carbonate, propylene carbonate, a monohydroxy alcohol having up to four carbon atoms, or limonene. In a thirteenth embodiment, this disclosure provides a primer composition according to the eleventh or twelfth embodiment, wherein the solvent comprises at least one of dimethyl carbonate, propylene carbonate, isopropanol, or limonene. In a fourteenth embodiment, this disclosure provides the use of the primer composition according to any one of the first to thirteenth embodiments as a primer for an adhesive tape.

[0122] In a fifteenth embodiment, this disclosure provides an adhesive system comprising a primer composition according to any one of the first to fourteenth embodiments and an adhesive tape. In a sixteenth embodiment, this disclosure provides an adhesive system according to the fifteenth embodiment, wherein the primer composition is not a component of the adhesive tape. In a seventeenth embodiment, this disclosure provides an adhesive system according to either the fifteenth or sixteenth embodiment, wherein the adhesive tape comprises at least one of an acrylic adhesive or a rubber adhesive. In an eighteenth embodiment, this disclosure provides an adhesive system according to any one of the fifteenth to seventeenth embodiments, wherein the adhesive tape is a pressure-sensitive adhesive tape. In a nineteenth embodiment, this disclosure provides an adhesive system according to any one of the fifteenth to seventeenth embodiments, wherein the adhesive tape is a semi-structural adhesive tape. In a twentieth embodiment, this disclosure provides an adhesive system according to the nineteenth embodiment, wherein the semi-structural tape includes an adhesive film comprising a first (meth)acrylate copolymer, the first (meth)acrylate copolymer comprising at least 55% by weight of linear or branched alkyl (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer, and 15% to 40% by weight of (meth)acrylate monomer units based on the weight of the first (meth)acrylate copolymer, wherein if the first (meth)acrylate copolymer comprises 15% by weight of (meth)acrylate monomer units, then the first (meth)acrylate copolymer comprises at least 5% by weight of high-T based on the weight of the first (meth)acrylate copolymer. g The monomer unit of the monomer, the high T gThe monomers, upon homopolymerization, provide a homopolymer with a glass transition temperature of at least 50°C; and monomer units comprising 0.10 wt% to 5 wt% of crosslinking monomers having more than one (meth)acrylate group, based on the weight of the first (meth)acrylate copolymer. In a twenty-first embodiment, this disclosure provides an adhesive system according to a twenty-first embodiment, wherein the first (meth)acrylate copolymer comprises 17 wt% to 20 wt% or 17 wt% to 19.5 wt% of (meth)acrylate monomer units. In a twenty-second embodiment, this disclosure provides an adhesive system according to a twenty-first embodiment or a twenty-first embodiment, wherein the first (meth)acrylate copolymer comprises at least 0.15 wt%, 0.20 wt%, 0.25 wt%, 0.30 wt%, 0.40 wt%, 0.50 wt%, 0.60 wt%, or 0.70 wt% of crosslinking monomer units having more than one (meth)acrylate group, based on the weight of the first (meth)acrylate copolymer. In a twenty-third embodiment, this disclosure provides an adhesive system according to any one of embodiments twenty to twenty-two, wherein the adhesive film comprises no more than 5% by weight of an additional (meth)acrylate copolymer, the additional (meth)acrylate copolymer comprising 0.1% to 15% by weight of (meth)acrylate monomer units based on the weight of the additional (meth)acrylate copolymer. In a twenty-fourth embodiment, this disclosure provides an adhesive system according to any one of embodiments fifteen to twenty-three, wherein the adhesive tape or adhesive film comprises foam. In a twenty-fifth embodiment, this disclosure provides an adhesive system according to any one of embodiments twenty to twenty-four, wherein the semi-structural adhesive tape is a multilayer adhesive assembly comprising a first layer of a first (meth)acrylate copolymer and a second adhesive layer adjacent to the first layer. In a twenty-sixth embodiment, this disclosure provides an adhesive system according to the twenty-fifth embodiment, wherein the first layer of the first (meth)acrylate copolymer is the core of a skin-core-skin multilayer adhesive. In a twenty-seventh embodiment, this disclosure provides an adhesive system according to any one of embodiments twenty to twenty-six, wherein the adhesive film further comprises a second (meth)acrylate copolymer comprising (meth)acrylate monomer units, based on a weight percentage of the second (meth)acrylate copolymer, greater than 15% to 40% by weight. In a twenty-eighth embodiment, this disclosure provides an adhesive system according to embodiment twenty-seven, wherein the first (meth)acrylate copolymer is present in an amount ranging from 65% to 99% by weight based on the total weight of the adhesive film, and wherein the second (meth)acrylate copolymer is present in an amount ranging from 1% to 35% by weight.In the twenty-ninth embodiment, this disclosure provides an adhesive system according to any one of the fifteenth to twenty-eighth embodiments, wherein the adhesive tape does not react with the primer composition to form covalent bonds.

[0123] In a thirtieth embodiment, this disclosure provides a method for manufacturing an adhesive article, the method comprising applying a primer composition according to any one of the first to thirteenth embodiments to a surface of a first substrate, and applying a semi-structural tape to the surface of the first substrate with the primer composition. In a thirty-first embodiment, this disclosure provides a method according to a thirty-ninth embodiment, wherein the semi-structural tape is a double-sided tape, the method further comprising applying the primer composition to a surface of a second substrate, and applying the semi-structural tape to the surface of the second substrate with the primer composition, thereby adhering the first substrate to the second substrate. In a thirty-second embodiment, this disclosure provides a method according to a thirty-ninth or thirty-first embodiment, wherein the semi-structural tape does not react with the primer composition to form covalent bonds.

[0124] The purposes and advantages of this disclosure are further illustrated by the following non-limiting embodiments, but the specific materials and quantities referenced in these embodiments, as well as other conditions and details, should not be regarded as undue limitations on this disclosure.

[0125] Example

[0126] Unless otherwise stated, all parts, percentages, ratios, etc., in the examples and the remainder of this specification are by weight. The following abbreviations are used in this section: in = inch, g = gram, µg = microgram, pph = percentage, wt% = weight%, kg = kilogram, lb = pound, kN = kilonewton, N = newton, lb f =pound force, h = hour, min = minute, s = second, ℃ = degree Celsius, ℉ = degree Fahrenheit, rH = relative humidity, Hz = hertz, mW = milliwatt, J = joule, ° = angle, m = meter, cm = centimeter, mm = millimeter, μm = micrometer, MPa = megapascal, psi = pound per square inch, and U / min = revolution per minute.

[0127] Test methods : by 300mm / min conduct 90° Peel test (according to test method) .Finat2 Number) : The adhesive tape composition and component strips, according to this disclosure, are longitudinally cut from the sample material and have a width of 10 mm and a length of >175 mm. For test sample preparation, a backing is first removed from one adhesive side and placed on an aluminum strip having dimensions of 22 cm × 1.6 cm. Then, after removing the backing, the adhesive-coated side of each adhesive tape strip is placed face down on a primer-coated test panel using light finger pressure. Next, the test sample is rolled twice in each direction at approximately 10 mm / s using a standard FINAT test roller (6.8 kg) to achieve close contact between the adhesive material and the surface. After applying the adhesive composition and component strips to the test panel, the test sample is allowed to remain at ambient room temperature (23°C + / - 2°C, 50% relative humidity + / - 5%) for 24 or 72 hours before testing.

[0128] For the peel test, in the first step, the test sample is clamped in the lower movable jaw of a Zwick tension tester (model Z020, commercially available from Zwick / Roell GmbH, Ulm, Germany). The adhesive film strip is folded back at a 90° angle, and the free end of the adhesive film strip is gripped in the upper jaw of the tension tester in a configuration commonly used for 90° peel measurements. The tension tester is set to a jaw separation rate of 300 mm / min. The test results are expressed in Newtons per 10 mm (N / 10 mm). The recorded peel value is the average of two 90° peel measurements.

[0129] 750g , 110℃ Static shear test ( FINAT Test methods 8 Number 2009 Year 8 version)

[0130] Static shear is a measure of the cohesiveness or internal strength of an adhesive. It is measured in minutes, in units of time, required to pull a standard area of ​​adhesive sheet material from a test panel under a constant standard load stress.

[0131] Cut a strip 25 mm wide and 12.7 mm long longitudinally from the cured adhesive sample. Remove a release liner from the strip and attach the adhesive tape sample through its exposed adhesive surface to an anodized aluminum backing. Then, remove a second release liner and attach the adhesive tape sample to the primer-coated test substrate, using light finger pressure to provide a 25 mm × 12.7 mm bonding area. Roll a standard FINAT test roller (6.8 kg) once in each direction at approximately 10 mm / s to achieve tight contact between the adhesive and the substrate surface. After applying the adhesive tape strip to the test panel, leave the test panel at room temperature for 24 hours before testing. Make a loop at the end of the test strip to secure a specified weight. Place the test panel in a shear holding device. After a 15-minute dwell time at a test temperature of 110°C, attach a 750 g load to the loop. Start the timer. Record the results in minutes and average three shear measurements. A recording time of “10000+” indicates that the adhesive has not failed after 10000 minutes.

[0132] based on ASTM D 1002 / DIN EN 1465 Single lap shear test (lap shear test)

[0133] Overlap shear (OLS) is a measure of the cohesiveness or internal strength of the adhesive. A 1-inch by 2-inch by 0.064-inch (2.5 cm by 5 cm by 1.1 mm) aluminum substrate supplied by Rocholl GmbH, Eschelbronn, Germany, was washed with MEK, then grating-blasted and cleaned with MEK, followed by air drying for 10 minutes. A primer was then applied to the substrate, covering approximately two inches. The primer-coated substrate was allowed to air dry for at least ten minutes before adhesive application. Test samples were prepared by cutting 1-inch (2 cm) strips of adhesive. One liner was removed, and the adhesive was laid on the primer-coated portion of the substrate. A 2-inch (5.1 cm) tight rubber roller was used to ensure complete contact of the adhesive. Bonding was achieved by removing the top of the exposed adhesive, peeling off the liner, and introducing it into the second primer-coated substrate. The closed bond was then subjected to an applied pressure of approximately 150 N for 30 seconds, and the bonded test assembly was left at room temperature (23°C + / - 2°C, 50% RH + / - 5%) for 3 days prior to testing. A dynamic lap shear test was performed at 23°C using a Zwick tension tester (model Z020, commercially available from Zwick / Roell GmbH, Ulm, Germany). The test specimen was loaded into the fixture, and the crosshead was operated at 1 inch / minute until failure. The fracture stress was recorded in MPa using the test method disclosed in ASTM D1002.

[0134] Shear storage modulus

[0135] A strain-controlled rheometer (model ARES G2, available from TA Instruments (159 Lukens Drive, NewCastle, DE 19720, USA)) equipped with an oscillating shear mode at a constant frequency of 1 Hz and featuring a parallel plate geometry (8 mm) was used. Samples cut from a circular die with an 8 mm diameter and 0.6 mm thickness were exposed to a temperature ramp from -50 °C to +150 °C at a heating rate of 5 °C / min. Oscillatory strain and normal force control were adjusted to maintain proper contact between the sample and the measurement geometry, and to control the degree of deformation within the linear viscoelastic region of the sample material, throughout the temperature range. The glass transition was determined as the peak temperature of the loss tangent. Complex modulus, storage modulus, and loss tangent were monitored throughout the temperature range, specifically measured at 25 °C. The complex modulus was evaluated for comparison with tape formulations. The complex modulus is determined by reflecting the storage modulus of the Dahlquist standard and the corresponding loss tangent tan δ, which is the ratio of the loss modulus to the storage modulus.

[0136] Test substrate

[0137] The adhesive properties of the adhesive tape compositions and components according to this disclosure are tested on the following substrates.

[0138] The stainless steel (SS) sheet (“Edelstahl 1.4301 IIID”, 150mm×50mm×2mm), aluminum (Al) sheet (1 inch by 2 inches by 0.064 inches (2.5cm by 5cm by 1.1mm)) and acrylonitrile butadiene styrene (ABS) sheet (AMetzoplastABS / G, 150mm×25mm×2mm) were all purchased from Rohl GmbH of Escherbrücke, Germany.

[0139] Before testing, clean the substrate as follows. Clean the Al and SS plates first with methyl ethyl ketone (MEK) and n-heptane, dry with tissue paper, then clean with MEK and dry with tissue paper. For the ABS plates, gently remove any residue / wax compounds from the surface with dry tissue paper, then clean with a mixture of isopropanol:distilled water (1:1) and dry with tissue paper.

[0140] Primer application process : Apply the primer using a wool dauber provided by 3M. The coating weight is approximately 0.02 g / 100 cm², which corresponds to a coating thickness of 2 μm. Allow the primer-coated substrate to air dry for at least ten minutes before applying the adhesive.

[0141]

[0142] Preparation Example FL-1 and Preparation Example SL-1

[0143] Precursors (hereinafter referred to as FL-1 and SL-1) for the adhesive compositions (foam layer and top layer) were prepared by combining a monomer composition containing C8 acrylate (2-EHA) and acrylic acid (AA) with 0.04 pph of PI 1 in a glass container. Prior to initiating UV exposure, the mixture was purged with nitrogen for 10 minutes, with nitrogen bubbled into the mixture for the entire time until the polymerization process was stopped by adding air to the slurry. The mixture was continuously stirred with a propeller stirrer (300 U / min) and the reaction was stopped when a viscosity of 2800 mPas to 4000 mPas was reached (measured using a Brookfield viscometer, model, city, country, T=25°C, spindle 4, 12 rpm). The photoinitiator PI 1, HDDA and HDDMA, and pyrolytic silica (FS) particles were then added and mixed again. In the third step, microspheres and black pigment are added, and the mixture is stirred for 5 minutes using a propeller stirrer (300 U / min) until the microspheres and black pigment are dissolved / dispersed. The exact formulations of the polymer precursor compositions used for the first adhesive polymer layer are listed in Table 2 below.

[0144] Preparation of acrylic copolymers : The (meth)acrylate copolymer, referred to below as copolymer 2, was prepared as follows. Polymerization was carried out using a Büchi Polycave stainless steel reactor (available from Büchi Labortechnik GmbH, City, The Netherlands). In the first step of polymerization, 250 g of a mixture of the following substances was charged into the Büchi reactor: EHA (80 wt%), AA (20 wt%), IOTG (0.04 wt%), and 3 ppm of "VAZO 52" initiator. The reactor was sealed and oxygen was removed, and then maintained under a nitrogen pressure of approximately 1 bar. The reaction mixture was heated to 60°C and then subjected to an adiabatic reaction. The peak reaction temperature was 110°C. When the reaction was complete, the mixture was cooled to below 50°C. The polymerization conversion was approximately 35%.

[0145] Preparation example FL-2 : The precursor composition of FL2 was prepared by first diluting copolymer 2 as described above in a polymer precursor composition containing C8 acrylate (EHA) and AA, as shown in Table 2 below. The resulting composition was consistently mixed by agitating it with a propeller stirrer (150 U / min) on a rolling worktable (model LD 209, available from Labortechnik Frobel, Germany) for approximately 24 hours, stopping when a clear, homogeneous mixture was obtained. Then, photoinitiator PI 1, HDDA crosslinking agent, and FS particles were added, and the mixture was mixed again by agitation for approximately 24 hours. In the third step, GB was added, and the mixture was stirred with a propeller stirrer (300 U / min) for 5 minutes until dispersed in glass bubbles.

[0146]

[0147] Preparation of semi-structural adhesive tape 1 and semi-structural adhesive tape 2

[0148] For the semi-structural adhesive tape 1, the precursors of the adhesive skin SL-1 and the first adhesive polymer foam core FL-1 were superimposed on each other in a laboratory coater according to the method described in WO-A1-2011094385 (Hitschmann et al.). This applied the liquid precursor of the adhesive skin (e.g., SL-1) to the bottom and top of the adhesive polymer foam core FL-1. The first scraper height was set to 120 µm (for the adhesive skin SL-1), and the second scraper height was set to 620 µm to 640 µm (for the polymer foam core FL-1), both measured from the substrate surface. The semi-structural adhesive tape 2 was prepared in the same manner, but without superimposing the skin onto the polymer foam core FL-2. Curing was completed from both the top and bottom sides in a 600 cm long UV curing stage at a linear velocity set to 1.30 m / min. The total cumulative radiation intensity from the top and bottom was approximately 4 mW / cm². 2 Semi-structural adhesive tape 1 includes a foam core layer FL-1 and two surface layers SL-1. Semi-structural adhesive tape 2 includes a foam core layer FL-2.

[0149] Preparation of polyacrylate

[0150] Polymer 2 was prepared via solution polymerization. A 40% by weight DMC solution was prepared by mixing 28 g of AA, 280 g of 2-EHA, 182 g of MMA, and 210 g of NVP with 1563.3 g of DMC and 70.0 g of isopropanol in a glass reactor. The mixture was degassed with nitrogen for 3 minutes and heated to 65°C. At this temperature, 5.60 g of "VAZO 67" initiator was added, and the mixture was reacted at 65°C with constant stirring for 24 hours.

[0151] Polymers 1 to 5 were also prepared by small-batch photopolymerization using 0.50 parts of PI 2 / 100 parts of monomer. For polymers 1 to 3, 0.50 parts of IOTG were also added, and for polymers 4 and 5, 0.10 parts of IOTG were also added. The polymers produced by photopolymerization were used to manufacture the primer compositions in the following examples. The composition of the monomers used for polymers 1 to 5 is listed in Table 3 below.

[0152]

[0153] Examples (Ex.) 1, Examples 2, Examples 4 and Examples 6 through 8 and Illustrative Example (IE) 3 and Illustrative Example 5

[0154] The primer composition is prepared by mixing the components shown in Table 4 below. First, the polymer is dissolved in a solvent and stirred until it becomes a clear solution. Next, the additives are added and the mixture is stirred again for at least one hour.

[0155]

[0156] The primer application process was used to apply the primer compositions shown in Table 4 for Examples (Ex.) 1, 2, 4, and 6 through 8, and the illustrative examples (IE). Then, the semi-structural adhesive tapes 2 of Examples 1, 2, 3, 4, and 5 were used as described above, and the semi-structural adhesive tapes 1 of Examples 6, 7, and 8 were used for a 90° peel test at 300 mm / min (according to test method Finat 2), a static shear test, and an overlap shear test. The results are shown in Table 4 above.

[0157] Using a primer application process, the primer composition shown in Table 4 for Example 8 and "3M UPUV PRIMER" were applied to various substrates shown in Table 5 below. Static shear tests and overlap shear tests were performed using semi-structural adhesive tape 2, and the results are shown in Table 5 below.

[0158]

[0159] The foregoing description, given to enable those skilled in the art to practice this disclosure protected by the claims, should not be construed as a limitation on the scope of this disclosure, which is defined by the claims and all their equivalents.

Claims

1. A primer composition comprising a polyacrylate dissolved in an organic solvent, the polyacrylate comprising, based on the total weight of monomer units in the polyacrylate: At least 20% by weight of methyl methacrylate units; At least 15% by weight of monomeric units comprising at least one of secondary amines, tertiary amines, or tertiary amides; At least 15% by weight of an acrylic monomer unit comprising an alkyl group having at least four carbon atoms; and Acrylic monomer units containing carboxylic acid groups, in a content of 0.5% to 10% by weight. The primer composition also does not contain polyamide.

2. The primer composition according to claim 1, wherein the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide comprises at least one of the following: 2-(N,N-dimethylaminoethyl)methacrylate, 2-(N,N-diethylaminoethyl)methacrylate, 2-(tert-butylaminoethyl)methacrylate, 2-(N,N-dimethylaminoethyl)methacrylamide, 2-(N,N-diethylaminoethyl)methacrylamide, 2-(tert-butylaminoethyl)methacrylamide, N-(meth)acryloylpiperidine, N-vinylcaprolactam, and N-vinyl-2-pyrrolidone.

3. The primer composition according to claim 1 or 2, wherein the methyl methacrylate unit, the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide, the acrylic monomer unit comprising an alkyl group having at least four carbon atoms, and the acrylic monomer unit comprising a carboxylic acid group together comprise at least 95% by weight of the monomer units in the polyacrylate.

4. The primer composition according to any one of claims 1 to 3, wherein the content of the methyl methacrylate unit is 25% to 65% by weight based on the total weight of the monomer units in the polyacrylate, wherein the content of the monomer unit comprising at least one of a secondary amine, a tertiary amine, or a tertiary amide is 15% to 40% by weight, wherein the content of the acrylic monomer unit comprising an alkyl group having at least four carbon atoms is 15% to 40% by weight, and wherein the content of the acrylic monomer unit comprising a carboxylic acid group is 2% to 7% by weight.

5. The primer composition according to claim 4, wherein the organic solvent comprises at least one of dimethyl carbonate, propylene carbonate, alcohol, polyol, polyol ether, diester, limonene, methylsiloxane, or ketone or ester having at most six carbon atoms.

6. The primer composition according to any one of claims 1 to 5, wherein the organic solvent comprises at least one of a monohydroxy alcohol having at most four carbon atoms, dimethyl carbonate, propylene carbonate, or limonene.

7. The primer composition according to claim 6, wherein the primer composition further comprises at least one of a silane or a titanate chelate.

8. The primer composition according to any one of claims 1 to 7, wherein, excluding the organic solvent, the polyacrylate accounts for at least 95% by weight of the primer composition.

9. Use of the primer composition according to any one of claims 1 to 8 as a primer for adhesive tape.

10. An adhesive system comprising a primer composition according to any one of claims 1 to 8 and an adhesive tape, wherein the primer composition is not a component of the adhesive tape.

11. The adhesive system of claim 10, wherein the adhesive tape comprises at least one of an acrylic adhesive or a rubber adhesive.

12. The adhesive system according to claim 10 or 11, wherein the adhesive tape is a semi-structural adhesive tape.

13. The adhesive system of claim 12, wherein the adhesive tape is a semi-structural adhesive tape, and wherein the semi-structural adhesive tape comprises: Adhesive film, the adhesive film comprising: A first (meth)acrylate copolymer, the first (meth)acrylate copolymer comprising: Based on the weight of the first (meth)acrylate copolymer, at least 55% by weight of linear or branched (meth)acrylate alkyl monomer units; Based on the weight of the first (meth)acrylate copolymer, 15% to 40% by weight of (meth)acrylate monomer units, wherein if the first (meth)acrylate copolymer comprises 15% by weight of (meth)acrylate monomer units, then the first (meth)acrylate copolymer comprises at least 5% by weight of high-T based on the weight of the first (meth)acrylate copolymer. g The monomer unit of the monomer, the high T g The monomers, during homopolymerization, provide a homopolymer with a glass transition temperature of at least 50°C; and Based on the weight of the first (meth)acrylate copolymer, 0.10% to 5% by weight of monomer units of crosslinking monomers having more than one (meth)acrylate group.

14. The adhesive system of claim 13, wherein the semi-structural adhesive tape is a multilayer adhesive assembly comprising a first layer of the first (meth)acrylate copolymer and a second adhesive layer adjacent to the first layer.

15. A method for manufacturing an adhesive article, the method comprising: The primer composition according to any one of claims 1 to 11 is applied to the surface of the first substrate; as well as The primer composition is applied to the surface of the first substrate using a semi-structural tape.

16. The method of claim 15, wherein the semi-structural band does not react with the primer composition to form covalent bonds.

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