WO2021124156A1

WO2021124156A1 - Method of pattern coating adhesive composition comprising unpolymerized cyclic olefin and latent catalyst, adhesive compositions and articles

Info

Publication number: WO2021124156A1
Application number: PCT/IB2020/062037
Authority: WO
Inventors: Binhong Lin; Erik M. TOWNSEND; Kelly A. VOLP; Michael A. Kropp; Mario A. Perez; Amanda K. LEONE
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2019-12-20
Filing date: 2020-12-16
Publication date: 2021-06-24
Anticipated expiration: 2022-06-20

Abstract

A method of bonding is described comprising providing a liquid adhesive composition comprising unpolymerized cyclic olefin and a latent ring opening metathesis polymerization catalyst or precatalyst thereof. The method further comprises disposing a pattern of the liquid adhesive composition on a substrate, contacting at least a portion of the liquid adhesive composition with a second substrate; and polymerizing the cyclic olefin by exposure to actinic radiation, heat, or a combination thereof. Also described is are articles comprising a first substrate adhered to a second substrate with a layer of an adhesive composition disposed in a pattern and liquid adhesive composition comprising unpolymerized cyclic olefin and latent ring opening metathesis polymerization catalyst or precatalyst thereof.

Description

METHOD OF PATTERN COATING ADHESIVE COMPOSITION COMPRISING UNPOLYMERIZED CYCLIC OLEFIN AND LATENT CATALYST, ADHESIVE COMPOSITIONS AND ARTICLES

Summary

Stencil printing of curable adhesive compositions is one common technique for precisely depositing a patterned layer of an adhesive compositions on a substrate with high resolution and consistent placement. To avoid premature curing of the curable adhesive precursor compositions on the stencil during printing, the curable adhesive compositions must have a sufficient latent time. Industry would find advantage in adhesive compositions comprising unpolymerized cyclic olefin and a latent catalyst suitable for use for stencil printing and other application techniques wherein latent curing is desired.

In one embodiment, a method of bonding is described comprising providing a liquid adhesive composition comprising unpolymerized cyclic olefin and a latent ring opening metathesis polymerization catalyst or precatalyst thereof. The method further comprises disposing a pattern of the liquid adhesive composition on a substrate, contacting at least a portion of the liquid adhesive composition with a second substrate; and polymerizing the cyclic olefin by exposure to actinic radiation, heat, or a combination thereof.

In another embodiment, an article is described comprising a first substrate adhered to a second substrate with a layer of an adhesive composition disposed in a pattern; wherein the adhesive layer comprises cyclic olefin polymerized with a latent ring opening metathesis polymerization catalyst or precatalyst.

In another embodiment, a liquid adhesive composition is described comprising unpolymerized cyclic olefin; latent ring opening metathesis polymerization catalyst or precatalyst thereof, wherein the catalyst or precatalyst thereof is activatable with actinic radiation. The latent catalyst is typically activated by heat, actinic radiation, a chemical compound, or a combination thereof. In one embodiment, the chemical compound is an acid, photoacid generator, or thermal acid generator.

Brief Description of the Drawing

FIG. 1 is atop plan view of the openings of a representative stencil suitable for overlap shear testing.

Detailed Description

The adhesive compositions described herein comprise one or more unpolymerized cyclic olefins. The cyclic olefins are generally mono-unsaturated (i.e. mono-olefin) or poly-unsaturated (i.e. comprising two or more carbon-carbon double bonds or in other words alkene groups). The double bond or in other words ethylenic unsaturation is not part of a (meth)acrylate or vinyl ether group. The cyclic olefin may be mono- or poly-cyclic (i.e. comprising two or more cyclic groups). The cyclic olefin may generally be a strained or unstrained cyclic olefin, provided the cyclic olefin is able to participate in a ROMP reaction either individually or as part of a ROMP cyclic olefin composition.

The polymerizable adhesive composition comprise cyclic diene monomers, including for example 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, 5-ethyl-l,3-cyclohexadiene, 1,3- cycloheptadiene, cyclohexadiene, 1,5-cyclooctadiene, 1,3-cyclooctadiene, norbomadiene, cyclohexenylnorbomene, including oligomers thereof such as dimers, trimers, tetramers, pentamers, etc. The polyolefin cyclic materials are amenable to thermosetting.

In some embodiments, the polymerizable adhesive composition comprises dicyclopentadiene (DCPD), depicted as follows:

Various DCPD suppliers and purities may be used such as Lyondell 108 (94.6% purity), Veliscol UHP (99+% purity), Cymetech Ultrene (97% and 99% purities), and Hitachi (99+% purity).

In some embodiments, the composition comprises cyclopentadiene oligomers including trimers, tetramers, pentamers, and the like; depicted as follows:

cyclopentadiene oligomers, n is typically 3, 4 or 5.

In some embodiments, the composition comprises cyclic diene monomer in the absence of mono- olefins.

In other embodiments, the composition further comprises a cyclic mono-olefin. Examples include cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cycloundecene, cyclododecene, tricyclodecene, tetracyclodecene, octacyclodecene, and cycloeicosene, and substituted versions thereof such as 1-methylcyclopentene, 1-ethylcyclopentene, 1-isopropylcyclohexene, 1- chloropentene, 1-fluorocyclopentene, 4-methylcyclopentene, 4-methoxy-cyclopentene, 4-ethoxy- cyclopentene, cyclopent-3-ene-thiol, cyclopent-3-ene, 4-methylsulfanyl-cyclopentene, 3- methylcyclohexene, 1-methylcyclooctene, 1,5-dimethylcyclooctene, etc.

In some embodiments, the composition further comprises norbomene, depicted as follows:

Suitable norbomene monomers include substituted norbomenes such as norbomene dicarboxylic anhydride (nadic anhydride); and as well as alkyl and cycloalkyl norbomenes including butyl norbomene, hexyl norbomene, octyl norbomene, decyl norbomene, and the like.

The cyclic olefin monomers and oligomers may optionally comprise substituents provided the monomer, oligomer, or mixture is suitable for metathesis reactions. The carbon atoms of the cyclic olefin moiety may optionally comprise substituents derived from radical fragments including halogens, pseudohalogens, alkyl, aryl, acyl, carboxyl, alkoxy, alkyl- and arylthiolate, amino, aminoalkyl, and the like, or in which one or more carbon atoms have been replaced by, for example, silicon, oxygen, sulfur, nitrogen, phosphoms, antimony, or boron. For example, the olefin may be substituted with one or more groups such as thiol, thioether, ketone, aldehyde, ester, ether, amine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, phosphate, phosphite, sulfate, sulfite, sulfonyl, carbodiimide, carboalkoxy, carbamate, halogen, or pseudohalogen. Similarly, the olefin may be substituted with one or more groups such as C1-C20 alkyl, aryl, acyl, C1-C20 alkoxide, aryloxide, C3-C20 alkyldiketonate, aryldiketonate, C1-C20 carboxylate, arylsulfonate, C1-C20 alkylsulfonate, C1-C20 alkylthio, arylthio, C1-C20 alkylsulfonyl, C1-C20 alkylsulfinyl, C-C20 alkylphosphate, and arylphosphate.

Preferred cyclic olefins can include dicyclopentadiene; tricyclopentadiene; dicyclohexadiene; norbomene; 5-methyl-2-norbomene; 5-ethyl-2-norbomene; 5-isobutyl-2-norbomene; 5,6-dimethyl-2- norbomene; 5-phenylnorbomene; 5-benzylnorbomene; 5-acetylnorbomene; 5- methoxycarbonylnorbomene; 5 -ethoxycarbonyl- 1 -norbomene ; 5 -methyl-5 -methoxy- carbonylnorbomene; 5-cyanonorbomene; 5,5,6-trimethyl-2-norbomene; cyclohexenylnorbomene; endo, exo-5,6-dimethoxynorbomene; endo, endo-5,6-dimethoxynorbomene; endo, exo-5-6- dimethoxycarbonylnorbomene; endo, endo-5,6-dimethoxycarbonylnorbomene; 2,3- dimethoxynorbomene; norbomadiene; tricycloundecene; tetracyclododecene; 8- methyltetracyclododecene; 8-ethyl-tetracyclododecene; 8-methoxycarbonyltetracyclododecene; 8- methyl-8-tetracyclo-dodecene; 8-cyanotetracyclododecene; pentacyclopentadecene; pentacyclohexadecene; higher order oligomers of cyclopentadiene such as cyclopentadiene tetramer, cyclopentadiene pentamer, and the like; and C2-C12 hydrocarbyl substituted norbomenes such as 5- butyl-2-norbomene; 5-hexyl-2-norbomene; 5-octyl-2-norbomene; 5-decyl-2-norbomene; 5-dodecyl-2- norbomene; 5-vinyl-2-norbomene; 5-ethylidene-2-norbomene; 5-isopropenyl-2-norbomene; 5- propenyl -2 -norbomene; and 5-butenyl-2-norbomene, and the like. More preferred cyclic olefins include dicyclopentadiene, tricyclopentadiene, and higher order oligomers of cyclopentadiene, such as cyclopentadiene tetramer, cyclopentadiene pentamer, and the like, tetracyclododecene, norbomene, and C2-C12 hydrocarbyl substituted norbomenes, such as 5 -butyl -2 -norbomene, 5-hexyl-2-norbomene, 5-octyl-2-norbomene, 5 -decyl -2 -norbomene, 5-dodecyl-2-norbomene, 5 -vinyl -2 -norbomene, 5- ethylidene-2-norbomene, 5 -isopropenyl-2 -norbomene, 5-propenyl-2-norbomene, 5-butenyl-2- norbomene, and the like.

The cyclic olefins may be used alone or mixed with each other in various combinations to adjust the properties of the olefin monomer composition. For example, mixtures of cyclopentadiene dimer and trimers offer a reduced melting point and yield cured olefin copolymers with increased mechanical strength and stiffness relative to pure poly-DCPD. As another example, incorporation of norbomene, or alkyl norbomene comonomers tend to yield cured olefin copolymers that are relatively soft and rubbery.

In some embodiments, the cyclic olefin material comprises a mixture of DCPD monomer and cyclopentadiene oligomer. In some embodiments, the mixture comprises at least 25, 30, 35, 40 or 45 wt.% DCPD based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises no greater than 75, 70, 65, 60, 55, or 50 wt.% DCPD based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises at least 15, 20, 25, 30, or 35 wt.% of cyclic olefin oligomers, such as cyclopentadiene trimer and/or tetramer based on the total amount a cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises no greater than 60, 55, 50, 45, or 40 wt.% of cyclic olefin oligomers, such as cyclopentadiene trimer and/or tetramer based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises at least 2, 3, 4, or 5 wt.% of cyclic olefin oligomers having greater than four cyclopentadiene repeat units, such as cyclopentadiene pentamer. In some embodiments, the mixture comprises no greater than 10, 9, 8, 7, 6, or 5 wt.% of cyclic olefin oligomers having greater than four cyclopentadiene repeat units, such as cyclopentadiene pentamer.

In some embodiments, the cyclic olefin material comprises a mixture of DCPD monomer and cyclopentadiene oligomer, in the absence of mono-olefins or in combination with a low concentration of mono-olefin. In this embodiment, the amount of mono-olefin is less than 25, 20, 15, 10, 9, 8, 7, 6,

5, 4, 3, 2, or 1 wt.% based on the total amount of cyclic olefin monomer(s) and oligomer(s).

In other embodiments, the mixture comprises at least 25, 30, 35, 40 or 45 wt.% of a mono-olefin such as a substituted norbomene, based on the total amount a cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises no greater than 75, 70, 65, 60, 55, or 50 wt.% mono-olefin (e.g. C4-C12 (e.g. C8) alkyl norbomene) based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises at least 15, 20, 25, 30, or 35 wt.% of cyclic olefin oligomers, such as cyclopentadiene trimer and/or tetramer based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises no greater than 60, 55, 50, 45, or 40 wt.% of cyclic olefin oligomers, such as cyclopentadiene trimer and/or tetramer based on the total amount of cyclic olefin monomer(s) and oligomer(s). In some embodiments, the mixture comprises at least 2, 3, 4, or 5 wt.% of cyclic olefin oligomers having greater than four cyclopentadiene repeat units, such as cyclopentadiene pentamer. In some embodiments, the mixture comprises no greater than 10, 9, 8, 7, 6, or 5 wt.% of cyclic olefin oligomers having greater than four cyclopentadiene repeat units, such as cyclopentadiene pentamer. In some embodiments, the mixture comprises no greater than 5, 4, 3, 2, or 1 wt.% of DCPD monomer. In other embodiments, the mixture comprises no greater than 25 or 20 wt.% of DCPD monomer.

The adhesive composition comprises at least 10, 11, 12, 14, or 15 wt.% of cyclic olefin (i.e. polyolefin and optional mono-olefin) of the sum of cyclic olefin(s) and polymer. In some embodiments, the amount of cyclic olefin is at least 16, 17, 18, 19, or 20 wt.% of the sum of cyclic olefin(s) and polymer. In some embodiments, the amount of cyclic olefin is at least 25, 30, 35, 40, 45, or 25 wt.% of the sum of cyclic olefin(s) and polymer. The amount of cyclic olefin (i.e. polyolefin and optional mono-olefin) is typically no greater than 80 wt.% of the sum of cyclic olefin(s) and polymer. In some embodiments, the amount of cyclic olefin is no greater than 75, 70, 55, 60, 55, or 50 wt.% of the sum or cyclic olefin(s) and polymer.

Various cyclic olefins are commercially available from Materia.

The adhesive compositions described herein are prepared by the metathesis of cyclic olefins polymerized with a metal carbene catalyst. Group 8 transition metals, such as ruthenium and osmium, carbene compounds have been described as effective catalysts for ring opening metathesis polymerization (ROMP). See for example US 10,239,965; incorporated herein by reference.

In typical embodiments, the catalyst is a metal carbene olefin metathesis catalyst. Such catalysts typically have the following structure:

(Catalyst Formula I) wherein

M is a Group 8 transition metal;

L¹, L², and L³ are independently neutral electron donor ligands; n is 0 or 1; m is 0, 1, or 2; k is 0 or 1;

X¹ and X² are independently anionic ligands; and R¹ and R² are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups.

Typical metal carbene olefin metathesis catalysts contain Ru or Os as the Group 8 transition metal, with Ru being preferred.

A first group of metal carbene olefin metathesis catalysts are commonly referred to as First Generation Grubbs-type catalysts, and have the structure of Catalyst Formula (I). For the first group of metal carbene olefin metathesis catalysts, M is a Group 8 transition metal, m is 0, 1, or 2, and n, X¹, X², L¹, L², and L³ are described as follows.

For the first group of metal carbene olefin metathesis catalysts, n is 0, and L¹ and L² are independently selected from phosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine, stibine, ether, (including cyclic ethers), amine, amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, substituted pyridine, imidazole, substituted imidazole, pyrazine, substituted pyrazine and thioether. Exemplary ligands are trisubstituted phosphines. Typical trisubstituted phosphines are of the formula PR^H1R^H2R^H3, where R^m, R^m, and R^H3 are each independently substituted or unsubstituted aryl or C1-C10 alkyl, particularly primary alkyl, secondary alkyl, or cycloalkyl. In some embodiments, L¹ and L² are independently selected from the group consisting of trimethylphosphine (PMe3), triethylphosphine (PEt3), tri-n-butylphosphine (RB_¾), tri(ortho-tolyl)phosphine (P-o-tolyE). tri-tert-butvlphosphine (P-tert-Bu3), tricyclopentylphosphine (PCyclopcntyE). tricyclohexylphosphine (PCy3), triisopropylphosphine (P-i-Pr3), trioctylphosphine (POct3), triisobutylphosphine, (P-i-Bm), triphenylphosphine (RR1¾), tri(pentafluorophenyl)phosphine (PIG.Fsfi). methyldiphenylphosphine (PMePli2), dimethylphenylphosphine (PMciPh). and diethylphenylphosphine (PEtiPh). Alternatively, L¹ and L² may be independently selected from phosphabicycloalkane (e.g., monosubstituted 9- phosphabicyclo-[3.3.1]nonane, or monosubstituted 9-phosphabicyclo[4.2.1]nonane] such as cyclohexylphoban, isopropylphoban, ethylphoban, methylphoban, butylphoban, pentylphoban and the like.

X¹ and X² are anionic ligands, and may be the same or different, or are linked together to form a cyclic group, typically although not necessarily a five- to eight-membered ring. In some embodiments, X¹ and X² are each independently hydrogen, halide, or one of the following groups: C1-C20 alkyl, C5- C24 aryl, C1-C20 alkoxy, C5-C24 aryloxy, C2-C20 alkoxy carbonyl, C6-C24 aryloxy carbonyl, C2- C24 acyl, C2-C24 acyloxy, C1-C20 alkylsulfonato, C5-C24 arylsulfonato, C1-C20 alkylsulfanyl, C5- C24 arylsulfanyl, C1-C20 alkylsulfinyl, NO₃, -N=C=0, -N=C=S, or C₅-C₂₄ arylsulfinyl. Optionally, X¹ and X² may be substituted with one or more moieties selected from C1-C12 alkyl, C1-C12 alkoxy, C5-C24 aryl, and halide, which may, in turn, with the exception of halide, be further substituted with one or more groups selected from halide, C1-C6 alkyl, C1-C6 alkoxy, and phenyl. In some embodiments, X¹ and X² are halide, benzoate, C2-C6 acyl, C2-C6 alkoxycarbonyl, C1-C6 alkyl, phenoxy, C1-C6 alkoxy, C1-C6 alkylsulfanyl, aryl, or C1-C6 alkylsulfonyl. In some preferred embodiments, X¹ and X² are each halide, CF3CO2, CH3CO2, CFH2CO2, (CFE^CO, (CF3)2(C]¾)CC), (CF₃)(CH₃)₂C0, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethane-sulfonate. In some preferred embodiments, X¹ and X² are each chloride.

R¹ and R² are independently selected from hydrogen, hydrocarbyl (e.g., C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), substituted hydrocarbyl (e.g., substituted C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6- C24 aralkyl, etc.), heteroatom-containing hydrocarbyl (e.g., heteroatom-containing C1-C20 alkyl, C2- C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), and substituted heteroatom -containing hydrocarbyl (e.g., substituted heteroatom-containing C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C5-C24 aryl, C6-C24 alkaryl, C6-C24 aralkyl, etc.), and functional groups. R¹ and R² may also be linked to form a cyclic group, which may be aliphatic or aromatic, and may contain substituents and/or heteroatoms. Generally, such a cyclic group will contain 4 to 12, preferably 5, 6, 7, or 8 ring atoms.

In some embodiments, R¹ is C1-C6 alkyl, C2-C6 alkenyl, and C5-C14 aryl.

In some embodiments, R² is phenyl, vinyl, methyl, isopropyl, or t-butyl, optionally substituted with one or more moieties selected from C1-C6 alkyl, C1-C6 alkoxy, phenyl, and a functional group Fn. Suitable functional groups ("Fn") include phosphonato, phosphoryl, phosphanyl, phosphino, sulfonato, C1-C20 alkylsulfanyl, C5-C20 arylsulfanyl, C1-C20 alkylsulfonyl, C5-C20 arylsulfonyl, C1-C.20 alkylsulfmyl, C5-C20 arylsulfmyl, sulfonamido, amino, amido, imino, nitro, nitroso, hydroxyl, C1-C20 alkoxy, C5-C20 aryloxy, C2-C20 alkoxycarbonyl, C5-C20 aryloxycarbonyl, carboxyl, carboxylato, mercapto, formyl, C1-C20 thioester, cyano, cyanato, thiocyanato, isocyanate, thioisocyanate, carbamoyl, epoxy, styrenyl, silyl, silyloxy, silanyl, siloxazanyl, boronato, boryl, or halogen, or a metal -containing or metalloid-containing group (wherein the metal may be, for example, Sn or Ge).

In some embodiments, R² is phenyl or vinyl substituted with one or more moieties selected from methyl, ethyl, chloro, bromo, iodo, fluoro, nitro, dimethylamino, methyl, methoxy, and phenyl. In some favored embodiments, R² is phenyl or -CH=C(CH3)2. In some embodiments, one or both of R¹ and R² may have the structure -(W)_n-U⁺V , wherein W is selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, or substituted heteroatom -containing hydrocarbylene; U is a positively charged Group 15 or Group 16 element substituted with hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, or substituted heteroatom-containing hydrocarbyl; V is a negatively charged counterion; and n is zero or 1. Furthermore, R¹ and R² may be taken together to form an indenylidene moiety, such as phenylindenylidene.

In some embodiments, any one or more of X¹, X², L¹, L², L³, R¹ and R² may be attached to a support or two or more (e.g. three or four) of said groups can be bonded to one another to form one or more cyclic groups, including bidentate or multidentate ligands, as disclosed, for example, in U.S. Pat. No. 5,312,940, incorporated herein by reference. When two or more of X¹, X², L¹, L², L³ R¹ and R² are linked to form cyclic groups, those cyclic groups may contain 4 to 12, preferably 4, 5, 6, 7 or 8 atoms, or may comprise two or three of such rings, which may be either fused or linked. The cyclic groups may be aliphatic or aromatic, and may be heteroatom-containing and/or substituted. The cyclic group may, in some cases, form a bidentate ligand or a tridentate ligand. Examples of bidentate ligands include, but are not limited to, bisphosphines, dialkoxides, alkyldiketonates, and aryldiketonates.

Other metal carbene olefin metathesis catalysts, commonly referred to as Second or Third Generation Grubbs-type catalysts, have the structure of Catalyst Formula (I), wherein L¹ is a carbene ligand having the structure of formula (II)

wherein M, m, n, X¹, X², L², L³, R¹ and R² are as previously defined Formula I;

X and Y are heteroatoms typically selected from N, O, S, and P. Since O and S are divalent, p is necessarily zero when X is O or S, q is necessarily zero when Y is O or S, and k is zero or 1. However, when X is N or P, then p is 1, and when Y is N or P, then q is 1. In a preferred embodiment, both X and Y are N;

Q¹, Q², Q³, and Q⁴ are linkers, e.g., hydrocarbylene (including substituted hydrocarbylene, heteroatom-containing hydrocarbylene, and substituted heteroatom-containing hydrocarbylene, such as substituted and/or heteroatom-containing alkylene) or -(CO)-, and w, x, y, and z are independently zero or 1, meaning that each linker is optional. Preferably, w, x, y, and z are all zero. Further, two or more substituents of adjacent atoms within Q¹, Q², Q³, and Q⁴ may be linked to form an additional cyclic group;

R³, R^3A, R⁴, and R^4A are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom -containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl. In addition, X and Y may be independently selected from carbon and one of the heteroatoms mentioned above, preferably no more than one of X or Y is carbon. Also, L² and L³may be taken together to form a single bidentate electron-donating heterocyclic ligand. Furthermore, R¹ and R² may be taken together to form an indenylidene moiety, preferably phenylindenylidene. Moreover, X¹, X², L², L³, X and Y may be further coordinated to boron or to a carboxylate;

Any two or more of X¹, X², L¹, L², L³, R¹, R² R³, R^3A, R⁴, R^4A, Q¹, Q², Q³, and Q⁴ can be bonded to one another to form one or more cyclic groups or can also be taken to be -A-Fn, wherein "A" is a divalent hydrocarbon moiety and Fn is a functional group as previously described. Further, with the exception of L¹ such groups may be bonded to a support.

A particular class of such carbene are commonly referred to as N-heterocyclic carbene (NHC) ligands.

Examples of N-heterocyclic carbene (NHC) ligands and acyclic diaminocarbene ligands suitable as LI thus include, but are not limited to, the following where DIPP or DiPP is diisopropylphenyl and Mes is 2,4,6-trimethylphenyl:

Representative metal carbene olefin metathesis catalysts include for example bis(tricyclohexylphosphine) benzylidene ruthenium dichloride, bis(tricyclohexylphosphine) dimethylvinylmethylidene ruthenium dichloride, bis(tricyclopentylphosphine) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(l,3-dimesityl-4,5- dihydroimidazol-2-ylidene) benzylidene ruthenium dichloride, (tricyclopentylphosphine)(l,3- dimesityl-4,5-dihydroimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(l,3-dimesityl-4,5-dihydroimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(l,3-dimesitylimidazol-2-ylidene) benzylidene ruthenium dichloride, (tricyclopentylphosphine)(l,3-dimesitylimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, and (tricyclohexylphosphine)(l,3-dimesitylimidazol- 2-ylidene) dimethylvinylmethylidene ruthenium dichloride.

Numerous metal carbene olefin metathesis catalysts are known, such as described in previously cited US 10,239,965.

In some embodiments, the adhesive compositions described herein are two-part composition wherein the latent catalyst is separated from the cyclic olefin until the time of use.

Latent ring opening metathesis polymerization catalysts exhibit little or no catalytic activity (e.g. polymerization of the cyclic olefin) while applying the adhesive composition prior to activation by heat, actinic radiation, or a combination thereof. Viscosity increase can be indicative of polymerization. The catalyst in sufficiently latent such that the viscosity of the adhesive is no greater than the maximum viscosity for a specified application method as will subsequently be described in greater detail.

Latent ring opening metathesis polymerization catalysts can be triggered or in other words activated with heat (i.e. thermal activation), actinic (e.g. ultraviolet) radiation, a chemical compound, or a combination thereof. In some embodiments, the latent ring opening polymerization catalysts are activated by a combination of actinic (e.g. ultraviolet) radiation and an acid compound. In some embodiments, a modified First or Second Generation Grubbs’ catalyst as previously described can function as a latent catalyst. One representative latent catalyst is depicted as follows:

Such catalyst can be activated with an acid, such as a photoacid generator (“PAG”), as depicted in the following reactive scheme:

Another class of latent catalysts comprise a carbyne, i.e. a (e.g. Ru) metal carbon triple bond (also described in the literature as (e.g. Ru) metals carbides). These catalysts can be characterized as a ring opening metathesis polymerization precatalyst because, such catalysts from a ring opening metathesis polymerization catalyst when reacted with an acid, such as a photoacid generator, as depicted in the following representative reactive scheme:

Such ring opening metathesis polymerization precatalysts can have the general formula:

wherein L¹ is a carbene ligand having the structure of formula (II)

wherein M, X¹, X², and L² are as previously defined for Formula I. In some embodiments, X¹ and X² are chlorine. In some embodiments, and L²is PCy₃.

In other embodiments, the latent catalyst can be activated by actinic (e.g. UV) energy in the absence of an acid compound. One class of compounds may be characterized as Fischer-type ruthenium carbene catalysts, such as described in WO2018/045132; incorporated herein by reference. Such catalysts have the following formula or a geometric isomer thereof.

wherein X¹ and X² are independently anionic ligands;

Y is 0, N-R¹, or S; and

Q is a two-atom linkage having the structure -CR^U-R¹²-CR¹³R¹⁴- or -C¹¹⁼CR¹³-; wherein, R¹¹, R¹², R¹³, and R¹⁴ are independently hydrogen, hydrocarbyl, or a substituted hydrocarbyl;

R¹ and R² independently hydrogen, (optionally substituted) hydrocarbyl, or may be linked together to form an (optionally substituted) cyclic aliphatic group;

R³ and R⁴ are independently (optionally substituted) hydrocarbyl, and

R⁵ R⁶ are independently H, Cl -24 alkyl, Cl -24 alkoxy, Cl -24 fluoroalkyl, Cl -24 fluoroalkoxy,

Cl -24 alkylhydroxy, Cl -24 alkoxyhydroxy, Cl -24 fluoroalkylhydroxy(including perfluoroalkylhydroxy),

Cl -24 fluoroalkoxyhydroxy, halo, cyano, nitro, or hydroxy; and m and n are independently 1, 2, 3, or 4.

In some embodiments, the moiety

is a N-heterocyclic carbene (NHC) ligand as described above. Other N-heterocyclic carbene (NHC) ligands include:

In one embodiment, the metathesis catalyst comprises a compound having the structure:

Actinic radiation activated catalysts can be preferred for bonding heat sensitive substrates comprised of organic polymeric materials. However, for bonding other substrates, the latent catalysts may be heat activated. In typical embodiments, the heat activation temperature is well above room temperature. For example, the heat activation temperature is at least 50, 60, 70, 80, 90 or 100°C. The heat activation temperature may range up to 130, 140, or 150°C. In one embodiment, thermally latent catalysts includes isomers that are inactive at room temperature yet active at temperatures ranging from 50°C to 90°C. One representative catalyst is as follows:

Another class of heat activatable catalyst comprises chelating alkylidene ligands. Some representative catalysts include:

The composition typically comprises the metathesis catalyst in an amount ranging from about 0.0001 wt.% to 2 wt.% catalyst based on the total weight of the composition. In some embodiments, the composition typically comprises at least 0.0005, 0.001, 0.005, 0.01, 0.05, 0.10, 0.15 or 0.20 wt.% catalyst. In some embodiments, the composition typically comprises no greater than 1.5, 1, or 0.5 wt.% catalyst.

In some embodiments, the activation of the latent olefin metathesis catalyst is achieved by the addition of acid, photoacid generator (“PAG”), or thermal acid generator (“TAG”) and exposing the composition to (e.g. ultraviolet) actinic radiation. When present, the acid, photoacid or thermal acid generator is typically present in the adhesive composition in an amount of at least 0.005 or 0.01 wt.% and typically no greater than 10 wt.% of the composition. In some embodiments, the concentration is no greater than 5, 4, 3, 2, 1, or 0.5 wt.% of the adhesive composition. Alternatively the acid, photoacid generator (“PAG”), or thermal acid generator (“TAG”) can be applied to the substrate the adhesive is applied to.

Upon irradiation with light energy, ionic photoacid generators undergo a fragmentation reaction and release one or more molecules of Lewis or Bronsted acid that activate the olefin metathesis catalyst. Useful photoacid generators are thermally stable and do not undergo thermally induced reactions with the copolymer and are readily dissolved or dispersed in the composition. Typical photoacid generators are those in which the incipient acid has a pKa value of □ 0. Photoacid generators are known and reference may be made to K. Dietliker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, vol. Ill, SITA Technology Ltd., London, 1991. Further reference may be made to Kirk-Othmer Encyclopedia of Chemical Technology, 4^th Edition, Supplement Volume, John Wiley and Sons, New York, year, pp 253-255.

Cations useful as the cationic portion of the ionic photoinitiators of the invention include organic onium cations, for example those described in U.S. Pat. Nos. 4,250,311, 3,708,296, 4,069,055, 4,216,288, 5,084,586, 5,124,417, 5,554,664 and such descriptions incorporated herein by reference, including aliphatic or aromatic Group IVA VIIA (CAS version) centered onium salts, preferably I-, S-, P-, Se- N- and C-centered onium salts, such as those selected from, sulfoxonium, iodonium, sulfonium, selenonium, pyridinium, carbonium and phosphonium, and most preferably I-, and S- centered onium salts, such as those selected from sulfoxonium, diaryliodonium, triarylsulfonium, diarylalkylsulfonium, dialkylarylsulfonium, and trialkylsulfonium wherein "aryl" and "alkyl" are as defined and having up to four independently selected substituents. The substituents on the aryl or alkyl moieties will preferably have less than 30 carbon atoms and up to 10 heteroatoms selected from N, S, non-peroxidic O, P, As, Si, Sn, B, Ge, Te, Se. Examples include hydrocarbyl groups such as methyl, ethyl, butyl, dodecyl, tetracosanyl, benzyl, allyl, benzylidene, ethenyl and ethynyl; hydrocarbyloxy groups such as methoxy, butoxy and phenoxy; hydrocarbylmercapto groups such as methylmercapto and phenylmercapto; hydrocarbyloxycarbonyl groups such as methoxycarbonyl and phenoxy carbonyl; hydrocarbylcarbonyl groups such as formyl, acetyl and benzoyl; hydrocarbylcarbonyloxy groups such as acetoxy and cyclohexanecarbonyloxy; hydrocarbylcarbonamido groups such as acetamido and benzamido; azo; boryl; halo groups such as chloro, bromo, iodo and fluoro; hydroxy; oxo; diphenylarsino; diphenylstilbino; trimethylgermano; trimethylsiloxy; and aromatic groups such as cyclopentadienyl, phenyl, tolyl, naphthyl, and indenyl. With the sulfonium salts, it is possible for the substituent to be further substituted with a dialkyl- or diarylsulfonium cation; an example of this would be 1,4-phenylene bis(diphenylsufonium).

Useful onium salts photoacid generator include diazonium salts, such as aryl diazonium salts; halonium salts, such as diarlyiodonium salts; sulfonium salts, such as triarylsulfonium salts, such as triphenyl sulfonium triflate; selenonium salts, such as triarylselenonium salts; sulfoxonium salts, such as triarylsulfoxonium salts; and other miscellaneous classes of onium salts such as triaryl phosphonium and arsonium salts, and pyrylium and thiopyrylium salts.

Ionic photoacid generators include, for example, bis(4-t-butylphenyl) iodonium hexafluoroantimonate (FP5034D from Hampford Research Inc., Stratford, CT), a mixture of triarylsulfonium salts (diphenyl(4-phenylthio) phenylsulfonium hexafluoroantimonate, bis(4- (diphenylsulfonio)phenyl)sulfide hexafluoroantimonate) available as Syna PI-6976 □ from Synasia, Metuchen, NJ, (4-methoxyphenyl)phenyl iodonium triflate, bis(4-/ -butylphenyl) iodonium camphorsulfonate, bis(4-/ -butylphenyl) iodonium hexafluoroantimonate, bis(4-fert-butylphenyl) iodonium hexafluorophosphate, bis(4-fert-butylphenyl) iodonium tetraphenylborate, bis(4-/ - butylphenyl) iodonium tosylate, bis(4-fert-butylphenyl) iodonium triflate, ([4- (octyloxy)phenyl]phenyliodonium hexafluorophosphate), ([4-(octyloxy)phenyl]phenyliodonium hexafluoroantimonate), (4-isopropylphenyl)(4-methylphenyl)iodonium tetrakis(pentafluorophenyl) borate (available as Rhodorsil 2074 □ from Bluestar Silicones, East Brunswick, NJ), bis(4- methylphenyl) iodonium hexafluorophosphate (available as Omnicat 440 □ from IGM Resins, Bartlett, IL), 4-(2-hydroxy-l-tetradecycloxy)phenyl]phenyl iodonium hexafluoroantimonate, triphenyl sulfonium hexafluoroantimonate (available as CT-548D from Chitec Technology Corp. Taipei, Taiwan), diphenyl(4-phenylthio)phenylsulfonium hexafluorophosphate, bis(4- (diphenylsulfonio)phenyl)sulfide bis(hexafluorophosphate), diphenyl(4-phenylthio)phenylsulfonium hexafluoroantimonate, bis(4-(diphenylsulfonio)phenyl)sulfide hexafluoroantimonate, and blends of these triarylsulfonium salts available from Synasia, Metuchen, NJ under the trade designations of Syna PI-6992 □ and Syna PI-6976 □ for the PR, and SbR salts, respectively.

In one embodiment, the photoacid generator is a triazine compound having the formula.

group, and 1 to 3 of Ri, R², R3 and R4 are hydrogen. The alkoxy groups typically have no greater than 12 carbon atoms. In favored embodiments, the alkoxy groups are independently methoxy or ethoxy. One representative species is 2,4,-bis(trichloromethyl)-6-(3,4-bis(methoxy)phenyl)-triazine. Such triazine compounds are further described in U.S. 4,330,590.

Optionally, the composition may include photosensitizers or photoaccelerators with the photoacid generators. Use of photosensitizers or photoaccelerators alters the wavelength sensitivity of radiation- sensitive compositions employing the latent catalysts and photoacid generators of this invention. This is particularly advantageous when the photoacid generator does not strongly absorb the incident radiation. Use of photosensitizers or photoaccelerators increases the radiation sensitivity, allowing shorter exposure times and/or use of less powerful sources of radiation.

Upon exposure to thermal energy, TAGs undergo a fragmentation reaction and release one or more molecules of Uewis or Bronsted acid. Useful TAGs are thermally stable up to the activation temperature. Preferred TAGs are those in which the incipient acid has a pK_a value of less than or equal to 0. Useful thermal acid generators have an activation temperature of 150°C or less, preferably 140°C or less. As used herein, "activation temperature" is that temperature at which the thermal release of the incipient acid by the TAG in the adhesive formulation occurs. Typically, the TAG will have an activation temperature in a range from about 50°C to about 150°C.

Useful classes of TAGs can include, for example, alkylammonium salts of sulfonic acids, such as triethylammonium p-toluenesulfonate (TEAPTS). Another suitable class of TAGs is that disclosed in U.S. Pat. No. 6,627,384 (Kim, et al.); incorporated herein by reference, which describes cyclic alcohols with adjacent sulfonate leaving groups. Suitable classes of thermal acid generators also include those described in U.S. Patent Nos. 7,514,202 (Ohsawa et al.) and 5,976,690 (Williams et al.); incorporated herein by reference.

Suitable ROMP catalysts or precatalysts can polymerize the cyclic olefin via thermal curing, exposure to actinic (e.g. UV) radiation, or a combination thereof.

The composition may optionally further comprise a rate modifier such as, for example, triphenylphosphine (TPP), tricyclopentylphosphine, tricyclohexylphosphine, triisopropylphosphine, trialkylphosphites, triarylphosphites, mixed phosphites, pyridine, or other Uewis base. The rate modifier may be added to the cyclic olefin component to retard or accelerate the rate of polymerization as required. The amount of rate modifier can be the same amounts just described for the catalyst. Typically, the amount of rate modifier is less than 0.01 or 0.005 wt.% based on the total amount of cyclic olefin. In some embodiments, the liquid adhesive composition further comprises a polymer. In some embodiments, the polymer thickens the liquid adhesive composition. In other embodiments, the polymer can be characterized as an adhesion promoter.

The amount of polymer is typically no greater than 20 wt.% based on the total amount of organic components cyclic olefm(s), catalyst, polymer, other optional organic components, such as tackifiers.

The composition optionally further comprises an adhesion promoter.

In some embodiments, the adhesion promoter is a compound or polymer containing at least two isocyanate groups. The adhesion promoter may be a diisocyanate, triisocyanate, or polyisocyanate (i.e., containing four or more isocyanate groups). The adhesion promoter may be a mixture of at least one diisocyanate, triisocyanate, or polyisocyanate. In some embodiments, the adhesion promoter is a diisocyanate compound, or mixtures of diisocyanate compounds.

In some embodiments, the adhesion promoters are polymeric polyisocyanates (e.g. diisocyanate) such as polyisocyanate prepolymers available from Convestro including the trade designations DESMODUR E-28 (MDI based) and Baytec ME-230 (modified MDI based on polytetramethylene ether glycol (PTMEG). Such polymeric polyisocyanates (e.g. diisocyanates) comprise C2-C4 alkylene oxide repeat units. Further, such polymeric polyisocyanates typically have an average equivalent weight ranging from 200-5000 g/mole per isocyanate group.

In some embodiments, the polymeric isocyanate adhesion promoter is typically the reaction product of a polyol and aliphatic diisocyanate such as MDI. The polyol typically has one or more oxygen atoms in the backbone such as in the case of polytetramethylene ether glycol and polypropylene oxide.

In some embodiments, the (e.g. polytetramethylene ether glycol) polyol has a molecular weight of about 90 g/mol. Such polymeric isocyanate may have a NCO content of greater than 15, 16, 17, 18,

19, or 20 wt.%. The NCO content is typically no greater than 25 wt.%.

In some embodiments, the (e.g. polypropylene oxide) polyol has a molecular weight of at least 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, or 2000 g/mol. The amount of polymerized polyol is typically less than 55, 50, 45, or 40 wt.% of the polymeric isocyanate. Such polymeric isocyanate may have a NCO content of greater than 10, 11, 12, 13, 14, or 15 wt.%. The NCO content is typically no greater than 20 wt.%. The equivalent weight of the polymeric polyol can be less than 400, 350, or 300 g/mole/NCO group. The equivalent weight is typically at least 150, 200 or 250 g/mole/NCO group. In some embodiments, the composition may comprise a maleic anhydride grafted polymer as an adhesion promoter such as available under the trade designation “POLYVEST MA 75” from Evonik, Essen, Germany and under the trade designation “RICON 131 Maleinized Polybutadiene 131MA10” from Cray Valley, Exton, PA. In this embodiment, the polymers may be characterized as polyolefins. The polyolefins may be unsaturated, comprising alkene moieties, such as polybutadiene. Unlike styrenic block copolymers, the olefin polymers lack polystyrene blocks.

In some embodiments, the polyolefin adhesion promoters have an average anhydride equivalent weight ranging from 200-5000 g/mole per anhydride group. In some embodiments, the average anhydride equivalent weight ranging is no greater than 4000, 3000, 2000, 1000 or g/mole per anhydride group.

The (e.g. polymeric polyisocyanate or olefin polymer comprising maleic anhydride moieties) adhesion promoter is a liquid, typically having a viscosity at 20 or 25 °C of at least 2000, 3000, 4000, or 5000 mPas. (DIN EN ISO 3219). In some embodiments, the viscosity at 20 or 25°C is no greater than 75,000 mPas. In some embodiments, the viscosity is no greater than 15,000 or 10,000 mPas. In some embodiments, the viscosity is less than 1000 or 500 mPas. In other embodiments, the adhesion promoter may have a viscosity of at least 50,000; 75,000; 100,000; 125,000 or 150,000 mPas at 45, 50, or 55°C. The viscosity is indicative of the molecular weight. Liquid adhesion promoters can be combined with the liquid unpolymerized cyclic olefin more easily than solids, resulting in the adhesion promoter being more uniformly dispersed within the mixture.

The adhesion promoter is polymeric i.e. having a backbone with (e.g. polyether or polyolefin) repeat units. In typical embodiments, the polymeric adhesion promoter has a molecular weight (Mn) of no greater than 10,000; 9,000; 8,000; 7,000; or 6,000 g/mole. In some embodiments, the polymeric adhesion promoter has a molecular weight (Mn) has a molecular weight of at least 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, or 2000 g/mole.

Various other adhesion promoters can be used alone or in combination with the polymeric adhesion promoters just described.

In some embodiments, the adhesion promoter is an aliphatic diisocyanate. Aliphatic diisocyanates comprise a linear, branched, or cyclic saturated or unsaturated hydrocarbon group typically containing 1 to about 24 carbon atoms. In some embodiments, the alkyl diisocyanate contains at least 2, 3, 4, 5, or 6 carbon atoms. In some embodiments, the aliphatic diisocyanate contains no greater than 22, 20, 18, 16, 14, or 12 carbon atoms. Representative examples include hexamethylene diisocyanate (HDI), octamethylene diisocyanate, decamethylene diisocyanate, and the like. In some embodiments, the aliphatic diisocyanate comprises a cycloaliphatic (e.g. cyclcoalkyl) moiety, typically having 4 to 16 carbon atoms, such as cyclohexyl, cyclooctyl, cyclodecyl, and the like. In one embodiments, the cycloalkyl diisocyanate is isophorone diisocyanate (IPDI) and the isomers of isocyanato- [(isocyanatocyclohexyl) methyl] cyclohexane (H12MDI).

In some embodiments, the adhesion promoter is an aromatic diisocyanate. Aromatic diisocyanates include one or more aromatic rings that are fused together or covalently bonded with an organic linking group such as an alkylene (e.g. methylene or ethylene) moiety. Representative aromatic moieties include phenyl, tolyl, xylyl, napthyl, biphenyl, diphenylether, benzophenone, and the like. Suitable aromatic diisocyanates contain 6 to 24 carbon atoms, such as toluene diisocyanates, xylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate (TMXDI), and methylene diphenyl diisocyanate (MDI), that may comprise any mixture of its three isomers, 2.2'-MDI, 2,4'-MDI, and 4,4'-MDI.

Other polymeric isocyanates include for example PM200 (poly MDI), Lupranate™ (poly MDI from BASF), various isocyanate terminated polybutadiene prepolymers available from Cray Valley including Krasol™ LBD2000 (TDI based), Krasol™ LBD3000 (TDI based), Krasol™ NN-22 (MDI based), Krasol™ NN-23 (MDI based), and Krasol™ NN-25 (MDI based).

In some embodiments, the adhesion promoter is a maleic -anhydride grafted styrene- ethylene/butylene -styrene hydrogenated copolymer, typically comprising at least 0.1, 0.2, 0.3, 0.4 or 0.5 wt.% of grafted maleic anhydride. The amount of grafted maleic anhydride is typically no greater than 7, 6, 5, 4, 3, or 2 wt. %. Maleic -anhydride grafted styrene-ethylene/butylene-styrene hydrogenated copolymers typically comprise at least 10 and no greater than 60, 50, or 40% polystyrene. Suitable functional elastomers are commercially available from Kraton Performance Polymers as the trade designations “Kraton FG1901G” and “Kraton FG1924G”. The amount of (e.g. functional) elastomer when present in typically at least 0.001, 0.05, or 0.1 wt.% based on the weight of the cyclic olefin.

The composition typically comprises at least 0.005, 0.010, 0.050, 0.10, 0.50, or 1 wt.% of adhesion promoter based on the total weight of the composition. In some embodiments, the amount of adhesion promoter is no greater than 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 wt.% of the total weight of the composition. In some embodiments, the adhesion promoter comprises one or more polymeric polyisocyanate (e.g. diisocyanate) comprising oxygen atoms in the backbone. In some embodiments, the adhesion promoter comprises one or more polyolefins comprising maleic anhydride moieties. In some embodiments, the adhesion promoter comprises at least one polymeric polyisocyanate (e.g. diisocyanate) comprising oxygen atoms in the backbone and at least one polyolefin comprising maleic anhydride moieties. When two adhesion promoters are used, the amount of each adhesion promoter is typically less than 5, 4, 3, 2, or 1 wt.% of the total weight of the composition.

The adhesive compositions may optionally contain one or more conventional additives. Preferred additives include tackifiers, plasticizers, antioxidants, UV stabilizers, colorants and (e.g. inorganic) fillers such as (e.g. fumed) silica and glass bubbles.

The cyclic olefin, polymer, and other components can be combined in various methods. In some embodiments, the materials are combined in an organic solvent such as toluene and ethyl acetate

The adhesive composition can be coated on a substrate using conventional coating techniques.

For example, these compositions can be applied to a variety of substrates by methods such as roller coating, flow coating, dip coating, spin coating, spray coating, knife coating, and die coating. Coating (dry) thickness typically ranges from 25 (e.g. about 1 mil) to 1500 microns (60 mils). In some embodiments, the coating thickness ranges from about 50 to 350 microns.

The method of applying and polymerizing the cyclic olefin of the composition will vary depending on the desired use of the composition. In favored embodiments, polymerization occurs after applying the adhesive article or adhesive composition to a substrate. However, in alternative embodiments polymerization of the composition (at least in part) may occurs prior to applying the composition to a substrate or concurrently with application to a substrate.

In some embodiments, the method comprises providing a liquid adhesive composition, as described herein, and disposing a pattern of the liquid adhesive composition on the substrate. Suitable methods of applying a pattern include, for example, piezo inkjet printing, valve jet printing, spray jet coating, hollow nozzle/needle dispensing, screen printing, flexographic printing, lithographic printing, screen printing and stencil printing. Of these, stencil printing and screen printing are presently preferred.

It is typically desirable to modify the viscosity (e.g., lower or higher) of the polymerizable adhesive composition in order for it to be suitable for the application method selected. For example, inkjet printing typically utilizes adhesive compositions having a viscosity of at least 5 to 10 cps ranging up to 20, 30, 40, or 50 cps. In the case of flexographic or gravure printing, the adhesive composition typically has a viscosity of 50 to 5000 cPs. In some embodiments, the viscosity is at least 100, 200, or 300 cps. In some embodiments, the viscosity is no greater than 4000, 3000, 2000, or 1000 cps. In the case of stencil printing, the adhesive composition typically has a viscosity of at least 1000, 1500, or 2000 cPs. In some embodiments, the viscosity is no greater than 20,000; 15,000; 10,000; or 5000 cps. In other embodiments, the viscosity of the polymerizable adhesive composition (e.g. for stencil printing) is greater than 20,000 cps. For example, the viscosity of the adhesive composition may be at least 30,000; 40,000; 50,000; 60,000 or 70,000 cps. The maximum viscosity is typically no greater than 250,000 cps. In some embodiments, the maximum viscosity is no greater than 200,000; 150,000, or 100,000 cps. Unless specified otherwise, the viscosity is the viscosity at 25°C measured with a Brookfield viscometer as further described in the examples. A polymer or a thixotrope, such as fumed silica, can be added to the adhesive composition to increase the viscosity. The viscosity can be reduced by addition of organic solvent.

The latent catalyst may partially polymerize the cyclic olefin at room temperature prior to being fully cured by exposure to heat and/or actinic radiation. Such partial polymerization also contributes to increasing the viscosity of the adhesive composition. In preferred embodiments, the catalyst is sufficiently latent such that after at least 1 hour (e.g. 4, 8, 12, or 24 hours) at 25°C, the viscosity is no greater than the maximum viscosity for the printing method. Thus, in case of stencil printing, the viscosity is less than 250,000; 200,000; 150,000, or 100,000 cps after at least 1 hour (e.g. 4, 8, 12, or 24 hours) at 25 °C.

One of ordinary skill in the art appreciates that stencil printing entails disposing a stencil on a (e.g. major) surface of a substrate.

The stencil comprises one or more openings. One representative stencil (suitable for concurrently preparing six overlap shear test samples) has six rectangular openings is depicted in FIG. 1. The opening(s) optionally further comprising a screen. The pattern of adhesive corresponds to the pattern of openings of the stencil. Each opening provides a discrete (i.e. individual, separate, distinct) adhesive region typically surrounded by a region lacking adhesive. On a macro scale, the overall pattern of adhesive may be characterized as discontinuous since the discrete adhesive regions are not connected to each other.

During stencil printing, a (e.g. metal or hard polyurethane) squeegee pushes the polymerizable adhesive composition down into the openings such that the adhesive contacts the underlying substrate and the openings is filled. The thickness of the adhesive in the opening corresponds to the thickness of the stencil. The substrate is typically kept flat during stencil printing. The squeegee speed depends on the viscosity. The lower the viscosity the higher the speed. Adhesives with higher viscosity utilize higher squeegee pressure than one with lower viscosity. Preferably, sufficient pressure is applied such that the stencil is wiped clean of adhesive each time the squeegee is conveyed along the stencil surface. In typical embodiment, the polymerizable adhesive composition is thixotropic, meaning the viscosity of the adhesive drops as a results of the shear forces applied during the application process. This aids in adhesive flow into the openings and onto the substrate.

Stencils for adhesive printing are usually stainless steel or (e.g. disposable) plastic. The advantage of plastic stencils is their flexibility that reduces the need of periodic cleaning of the stencil like stencils of stainless steel. However, plastic stencils are not as durable as the one of stainless steel. Stencils are suitable for preparing fine-pitch prints having a thickness less than 20, 15 or 10 mils.

The positional accuracy of an adhesive application system can be data-driven. Each point of adhesive deposit can be measured from its coordinate position in a CAD system. Any rotational offset or expansion/contraction of the adhesive pattern can be adjusted, point by point, using fiducial correction or a “best-fit” algorithm. A stencil typically cannot be changed to meet the dimensional variations of the substrate. To overcome this problem, adhesive application systems compensate for fluctuation in substrate thickness and warp by utilizing support pins and vacuum supports.

Linear pumps, having a positive displacement piston pump are typically favored over rotary pumps for dispensing the adhesive. Linear pumps are typically not affected by fluid viscosity, pressure, needle size or fluid/pump temperature. The pump’s servo drive mechanism allows programmable shot sizes and flow rates.

After application of the adhesive to the substrate, the unpolymerized adhesive is removed from the squeegee and stencil periodically by cleaning (e.g. with an organic solvent). The adhesive will eventually cure, making it more difficult to remove later. Due to the latency of the catalyst (prior to exposure to heat and/or actinic radiation) the squeegee and stencil can be cleaned less often.

The substrate may also be formed of metal, metalized polymer films, ceramic sheet materials, or foam (e.g., polyacrylic, polyethylene, polyurethane, neoprene), and the like.

Substrate materials for either of the first and/or second substrates include, metal, glass, plastic, ceramic, wood, composite materials, and combinations thereof. Examples of plastic sheets or films include polyolefins (e.g. polypropylene, polyethylene), polyvinyl chloride, polyester (polyethylene terephthalate), polycarbonate, polymethyl(meth)acrylate (PMMA), cellulose acetate, cellulose triacetate, and ethyl cellulose. In some embodiments, the substrate is comprised of a bio-based material such as polylactic acid (PLA).

Substrates may also be prepared of fabric such as woven fabric formed of threads of synthetic or natural materials such as cotton, nylon, rayon, glass, ceramic materials, and the like or nonwoven fabric such as air laid webs of natural or synthetic fibers or blends of these. When the cyclic olefin is polymerized with a ROMP catalyst activated by exposure to actinic (e.g. UV) radiation, the adhesive composition (e.g. of the adhesive article) may be irradiated with activating UV radiation having a UVA maximum at a wavelength range of 280 to 425 nanometers. UV light sources can be of various types. Low light intensity sources, such as blacklights, generally provide intensities ranging from 0.1 or 0.5 mW/cm² (milliwatts per square centimeter) to 10 mW/cm² (as measured in accordance with procedures approved by the United States National Institute of Standards and Technology as, for example, with a UVIMAP UM 365 L-S radiometer manufactured by Electronic Instrumentation & Technology, Inc., in Sterling, VA). High light intensity sources generally provide intensities greater than 10, 15, or 20 mW/cm² ranging up to 450 mW/cm² or greater. In some embodiments, high intensity light sources provide intensities up to 500, 600, 700, 800, 900 or 1000 mW/cm². UV light to polymerize the cyclic olefm(s) can be provided by various light sources such as light emitting diodes (LEDs), blacklights, medium pressure mercury lamps, etc. or a combination thereof. The cyclic olefm(s) can also be polymerized with higher intensity light sources as available from Fusion UV Systems Inc. The UV exposure time for polymerization and curing can vary depending on the intensity of the light source(s) used. For example, complete curing with a low intensity light source can be accomplished with an exposure time ranging from about 30 to 300 seconds; whereas complete curing with a high intensity light source can be accomplished with shorter exposure time ranging from about 5 to 20 seconds. Partial curing with a high intensity light source can typically be accomplished with exposure times ranging from about 2 seconds to about 5 or 10 seconds.

Alternatively or in combination thereof, when the cyclic olefin is polymerized with a thermally activated ROMP catalyst, the adhesive is heated as previously described.

The adhesive composition is typically not a pressure sensitive adhesive after polymerizing the cyclic olefin. In this embodiment, the storage modulus (G’) of the adhesive after polymerizing the cyclic olefin is at least (e.g. 25°C) 3 x 10⁵ Pa at a frequency of 1 Hz. In some embodiments, the adhesive composition has a storage modulus of a least than 4 x 10⁵ Pa, 5 x 10⁵ Pa, 6 x 10⁵ Pa, 7 x 10⁵ Pa, 8 x 10⁵ Pa, 9 x 10⁵ Pa, 1 x 10⁶ Pa, 2 x 10⁶ Pa, 3 x 10⁶ Pa, 4 x 10⁶ Pa, 5 x 10⁶ Pa or greater after polymerizing the cyclic olefin. In this embodiment, the adhesive composition may be characterized as a structural adhesive composition.

In some embodiments, the polymerizable composition provides a structural and semi- structural adhesive composition in which the composition may be disposed between two substrates and subsequently fully cured to create a structural or semi-structural bond between the substrates. "Semi-structural adhesives" are those cured adhesives that have an overlap shear strength (according to the test method of the examples) of at least about 0.5 MPa, more preferably at least about 1.0 MPa, and most preferably at least about 1.5 MPa. Those cured adhesives having particularly high overlap shear strength, however, are referred to as structural adhesives. "Structural adhesives" are those cured adhesives that have an overlap shear strength of at least about 3.5 MPa, more preferably at least about 5 MPa, and most preferably at least about 7 MPa. The overlap shear strength can be determined according to the method further described in the examples.

Objects and advantages of this invention are further illustrated by the following examples.

The particular materials and amounts, as well as other conditions and details, recited in these examples should not be used to unduly limit this invention. EXAMPLES

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

Materials Used in the Examples

Dynamic Overlap Shear Test

A dynamic overlap shear test was performed at ambient temperature using an MTS CRITERION MODEL 43 tensile tester (MTS, Eden Prairie, MN) equipped with an LPS.104 C 10 kN load cell (MTS, Eden Prairie, MN). Test specimens were loaded into the grips and the crosshead was operated at 0.1” (0.25 cm) per minute, loading the specimen to failure. Stress at break was recorded in units of psi and converted to pascals (or kilopascals). Three specimens of each sample were tested, and the average result calculated.

Example 1 The reagents from Table 2 were added with glass beads (2 mg of 3-5 mil glass beads per 10 mL resin) in a plastic cup and then mixed in a DAC 150.1 FVZ-K speed mixer (FlackTek, Inc., Landrum, SC) at 3000 rpm for 1 minute. Aluminum (Al) coupons (1 inch x 4 inch x 0.064 inch) were abraded with SCOTCH-BRITE GENERAL PURPOSE HAND PAD #7447 (3M), cleaned with isopropanol, and then air-dried. At the tip of one coupon, a 0.5 inch by 1 inch square was coated with a thin layer of reaction mixture with a tongue depressor (~25 mil thick). For the samples that were exposed to UV irradiation were passed through a Fusion Processor with the D Bulb (21 UVA/cm² 0.51 UVB/cm², 0.2 I UVC/cm², 21 UVV/cm² as measured on the EIT Powerpuck II). To close the bond, the coupon with the adhesive contacted with another coupon in the opposite tip direction. Clips were used to hold the two halves together during the curing process. Sample 3-1 was then cured at 80°C (or room temperature) for 24 hours prior to dynamic overlap shear testing.

Table 2. Adhesive composition for Example 1.

This adhesive composition was also tested excluding the photoacid generator (TASC1 solution).

Table 3. Dynamic Overlap Shear Testing results for Example 1.

Examnle 2 - Stencil Printing with Heat Curing

The reagents from Table 4 were added to a plastic cup and then mixed in a DAC 150.1 FVZ-K speed mixer (FlackTek, Inc., Landrum, SC) at 3000 rpm for 1 minute. Aluminum (Al) coupons (1 inch x 4 inch x 0.064 inch) were abraded with SCOTCH-BRITE GENERAL PURPOSE HAND PAD #7447 (3M), cleaned with isopropanol, and then air-dried. At the tip of one coupon, a 0.5 inch by 1 inch portion was coated with a 10 mil thick layer of the following adhesive composition with a stencil printer having the pattern depicted in FIG. 1. To close the bond, the coupon with the adhesive contacted with another coupon (without any adhesives) to form a 0.5 inch by 1 inch overlap area Clips were used to hold the two halves together during the curing process. The samples were then cured at 80°C in the dark for 24 hours prior to dynamic overlap shear testing.

Table 4. Adhesive formulation for Example 2.

The adhesive formulation as described in Table 4 was loaded into a 40mL vial, which was then loaded into a Brookfield Viscometer (DV2T). Using a 07 spindle and a speed of 10 rpm, a viscosity measurement was recorded after 5 minutes and again after 1 hour. The viscosity increase of 19000 cp (28%) is believed indicative of partial polymerization of the cyclic olefin.

Table 5. Dynamic Overlap Shear Testing results for Example 2.

Example 3- Stencil Printing with UV and Heat Curing

The reagents from Table 6 were added to a plastic cup and then mixed in a DAC 150.1 FVZ-K speed mixer (FlackTek, Inc., Landrum, SC) at 3000 rpm for 1 minute. Nylon 6,6 coupons (1 inch x 4 inch x 0.064 inch) were cleaned with isopropanol and then air-dried. At the tip of one coupon, a 0.5 inch by 1 inch portion was coated with a thin layer of the following adhesive composition with the same stencil printer as Example 2. The samples were passed through a Fusion Processor with the D Bulb (2J UVA/cm² 0.5J UVB/cm², 0.2 J UVC/cm², 2J UVV/cm² as measured on the EIT Powerpuck II). To close the bond, the coupon with the adhesive contacted with another coupon in the opposite tip direction. Clips were used to hold the two halves together during the curing process. The samples were then cured at 80°C for 24 hours prior to dynamic overlap shear testing.

Table 6. Adhesive formulation for Example 3.

Table 7. Dynamic Overlap Shear Testing results for Example 3.

Claims

What is claimed is:

1. A method of bonding comprising: providing a liquid adhesive composition comprising: unpolymerized cyclic olefin; and a latent ring opening metathesis polymerization catalyst or precatalyst thereof; disposing a pattern of the liquid adhesive composition on a substrate; polymerizing the cyclic olefin by exposure to actinic radiation, heat, or a combination thereof contacting at least a portion of the liquid adhesive composition with a second substrate.

2. The method of claim 1 wherein the cyclic olefin comprises moieties selected from cyclopentadiene, norbomene, and oligomers thereof.

3. The method of claims 1-2 wherein the cyclic olefin is present in an amount of at least 50 wt.% based on the total weight of organic components.

4. The method of claims 1-3 wherein the catalyst is a ruthenium or osmium metal carbene catalyst.

5. The method of claims 1-4 wherein the latent catalyst is activated by heat, actinic radiation, a chemical compound, or a combination thereof.

6. The method of claims 1-5 wherein the chemical compound is an acid, photoacid generator, or thermal acid generator.

7. The method of claim 1-6 wherein the catalyst or precatalyst thereof is sufficiently latent such that the adhesive composition has a viscosity of less than 20,000 cps after 1 hour at 25°C.

8. The method of claim 7 wherein the adhesive composition after polymerization of the cyclic olefin exhibits an overlap shear value with aluminum of at least 3.5MPa.

9. The method of claims 1-7 wherein the adhesive composition further comprises one or more polymers.

10. The method of claims 1-9 wherein the amount of polymer is no greater than 10 wt.% solids of the total amount of cyclic olefin and polymer.

11. The method of claims 9-10 wherein at least one polymer is a polymeric polyisocyanate comprising oxygen atoms in the backbone, a polyolefin comprising maleic anhydride moieties, a combination thereof.

12. The method of claims 9-11 wherein the polymer is maleated polybutadiene.

13. The method of claims 1-12 wherein the adhesive composition is a two-part adhesive composition wherein the catalyst is in a separate part than the unpolymerized cyclic olefin.

14. The method of claims 1-13 wherein polymerizing the cyclic olefin by exposure to actinic radiation utilizes ultraviolet radiation.

15. The method of claims 1-14 wherein polymerizing the cyclic olefin comprises exposure to actinic radiation followed by exposure to heat.

16. The method of claims 1-15 wherein the substrate comprises an organic polymer or an inorganic material.

17. The method of claims 1-16 wherein the first substrate and second substrate comprises the same or different materials.

18. The method of claim 17 wherein disposing a pattern of the liquid adhesive composition comprises disposing a stencil of a surface of the substrate, wherein the stencil comprises one or more openings, the opening(s) optionally further comprising a screen and applying the liquid adhesive composition to the stencil.

19. An article comprising a first substrate adhered to a second substrate with a layer of an adhesive composition disposed in a pattern; wherein the adhesive layer comprises cyclic olefin polymerized with a latent ring opening metathesis polymerization catalyst or precatalyst.

20. The article of claim 19 wherein the adhesive composition, unpolymerized cyclic olefin, or latent ring opening metathesis polymerization catalyst is further characterized by claims 2-13

21. A composition comprising: unpolymerized cyclic olefin; latent ring opening metathesis polymerization catalyst or precatalyst thereof, wherein the catalyst or precatalyst thereof is activatable with actinic radiation; wherein the composition is a liquid adhesive composition.

22. The composition of claim 21 wherein the latent catalyst is activated by heat, actinic radiation, a chemical compound, or a combination thereof.

23. The composition of claim 21-22 wherein the chemical compound is an acid, photoacid generator, or thermal acid generator.

24. The composition of claims 21-23 wherein the composition, unpolymerized cyclic olefin, or latent ring opening metathesis polymerization catalyst is further characterized by claims 2-4 and 7-13.