Photocurable adhesive compositions

Abstract

This disclosure relates to photocurable (meth)acrylate compositions which when cured have low uncured viscosity and / or high cured lap shear strength and / or are free of health hazardous and / or toxic chemicals. The compositions include a polyurethane (meth)acrylate oligomer, an acrylamide, a vinyl cyclic amide and a photoinitiator. The compositions are suitable for use as adhesives on many substrates.

Description

2024P00004 Photocurable Adhesive Compositions Field

[0001] In one embodiment the present invention relates to photo-curable (meth)acrylate adhesive compositions The compositions include a urethane (meth)acrylate oligomer, one or more acrylamides, one or more vinyl cyclic amides, a photoinitiator and optional additives. Brief Description

[0002] Light cured or photo-cured compositions are compositions curable using radiation such as visible or ultraviolet light (UV). It is desirable for these compositions to have a balance of molecular weight and viscosity, in order to be applied effectively. Additionally, for better workability, reactive acrylic diluents are often added. These acrylic monomers are generally low molecular weight compounds having one or more acrylate functional groups.

[0003] For example, current commercially available (meth)acrylate-based photo- curable compositions generally contain only low molecular weight acrylates such as isobornyl (meth)acrylate (IBOA M.W.222.32) and N,N-dimethylacetamide (N,N'-DMA M.W.87.12), or epoxy monomers which might not be desirable for some applications. Notwithstanding the fact that photo-curing and crosslinking of these compositions takes place rapidly, unreacted monomers, or monomer components and impurities, still may leach out, or they may be extracted under certain conditions, presenting potential problems for certain uses.

[0004] One way to address this problem is to use monomers with higher molecular weights, but this approach generally leads to lower reactivity and often has a negative impact on properties, such as viscosity and adhesion strength to different substrates. Thus, most commercially available photo-curable acrylate products use low molecular weight (meth)acrylate monomers which may be listed as health hazard or toxic chemicals.2024P00004 SUMMARY

[0005] It would be advantageous to find a photo-curable composition which has one or more of the following desirable properties: a low uncured viscosity to ease workability; desirably high adhesion strength when cured; and / or free of health hazardous and / or toxic chemicals to increase safety. The present invention provides such a solution by using specially chosen components in a limited ratio.

[0006] The disclosed compositions do not have pressure-sensitive properties and would not be suitable for use as a pressure sensitive adhesive. The disclosed compositions typically have a viscosity too high for use as an ink and reducing viscosity will take away from the properties desirable in an adhesive. The disclosed compositions are not expected to have properties desirable for use as a three- dimensional printing or molding composition.

[0007] One aspect of the invention includes, a photo-curable adhesive composition comprising: a) a urethane (meth)acrylate oligomer; b) an acrylamide; c) a vinyl cyclic amide; and d) a photoinitiator; wherein the ratios of the acrylamide / vinyl amide may range from about 0.5 / 1 to 1 / 0.5 based on wt.% of the acrylamide and vinyl cyclic amide in the composition; and wherein the cured reaction products of the photo-curable adhesive composition exhibit desirably high adhesion to substrates, especially polycarbonate and reinforced epoxy substrates.

[0008] In another aspect of the invention, there is included a method of forming a bonded article by applying the photo-curable adhesive composition to a first substrate, disposing a second substrate over the adhesive and first substrate, exposing the adhesive to radiation to crosslink and cure the adhesive composition. Articles incorporating the composition as a layer, a bond, or an adhesive are also included.2024P00004 DETAILED DESCRIPTION Definitions

[0009] The word “about” or “approximately” as used herein in connection with a numerical value refer to the numerical value ± 10%, preferably ± 5% and more preferably ± 1% or less.

[0010] "Alkyl" refers to a linear, branched or cyclic alkyl group having from 1 to about 10 carbon atoms including, for example, methyl, ethyl, propyl, butyl, hexyl, octyl, isopropyl, isobutyl, tert-butyl, cyclopropyl, cyclohexyl, cyclooctyl, vinyl and allyl. Unless otherwise specifically defined, an alkyl group can be saturated or unsaturated and substituted or unsubstituted. The term "(meth)acryl" as used herein indicates acryl (CH2=CHCO-*), methacryl (CH2=C(CH3)CO-*) or any combination thereof. Similarly, the term "(meth)acryloxy" indicates acryloxy, methacryloxy or any combination thereof; the term "(meth)acrylic acid" indicates acrylic acid, methacrylic acid or any combination thereof; the term "(meth)acrylate" indicates acrylate, methacrylate or any combination thereof; and the term "(meth)acrylamide" indicates acrylamide, methacrylamide or any combination thereof. The number of the (meth)acryl groups in the (meth)acrylate usable in the present invention is not particularly limited and can be one or more.

[0011] Health hazard means chemicals classified as requiring a health hazard warning under OSHA 29 C.F.R 1910.1200.

[0012] Toxic means chemicals classified as requiring a toxic warning under OSHA 29 C.F.R 1910.1200.

[0013] “Oligomer” as used herein refers to polymeric compounds which include a plurality of monomer units linked to each other. Desirably the oligomer includes from 2 to 1000 monomer units linked to each other, and more desirably 2 to 300 monomer units. Desirably the oligomer has a weight average molecular weight of about 500 to 10,000 g / mol, preferably 500 to 5,00 and more preferably 500 to 1,000 g / mol.

[0014] The recitation of numerical end points in a range includes all numbers and fractions subsumed within the respective range, as well as the recited end points.

[0015] “Substituted” means substituted by at least one below described substituent group in any possible position or positions. Substituent groups useful in the disclosed2024P00004 compounds are those groups that do not significantly diminish the activity of the disclosed compound. Useful substituent groups include, for example, H, halogen, OH, alkyl, alkoxy.

[0016] Weight average molecular weight (Mw) means the average weight fraction of molecules in a sample. Number average molecular weight means the average number fraction of molecules in a sample. Molecular weight data can be obtained in known ways such as by gel permeation chromatography (GPC) calibrated against polystyrene standards in accordance with DIN 55672-1:2007-08. The number average molecular weight Mn can be determined by the same methods.

[0017] All percentages that are cited in connection with the compositions described herein refer to weight percent (wt.%) with respect to final composition with all components, unless stated otherwise.

[0018] The disclosed compounds include any and all isomers and steroisomers. In general, unless otherwise explicitly stated, the disclosed materials and processes may be alternately formulated to comprise, consist of, or consist essentially of, any appropriate components, moieties or steps herein disclosed. The disclosed materials and processes may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, moieties, species and steps used in the prior art compositions or that are otherwise not necessary to the achievement of the function and / or objective of the present disclosure.

[0019] This invention provides, photocurable (meth)acrylate containing compositions which, in one embodiment, include a polyurethane (meth)acrylate oligomer; an acrylamide, a vinyl cyclic amide and a photoinitiator. The acrylamide and the vinyl cyclic amide are present in a specific range of ratios. polyurethane (meth)acrylate oligomers

[0020] The polyurethane (meth)acrylate oligomers used in the compositions have relatively low viscosities by themselves, which facilitate the formation of desirable low viscosities in the photo-curable compositions to which they are added.

[0021] Useful polyurethane (meth)acrylate oligomers can be made from the reaction of a mono-(meth)acrylate monomer containing one or more hydroxyl terminal group(s) and hexamethylene diisocyanate(HDI) isocyanurate. Some useful polyurethane2024P00004 (meth)acrylate oligomers are commercially available, for example EBECRYL aliphatic urethane diacrylate available from Allnex, PHOTOMER aliphatic urethane triacrylates available from IGM and BR528 aliphatic urethane diacrylate available from Dymax.

[0022] The polyurethane (meth)acrylate oligomer is present in the amount of about 20% to about 60%, about 25% to about 60%, about 30% to about 60%, about 35% to about 60%,about 40% to about 60%, about 45% to about 60%, about 50% to about 60%, about 55% to about 60%; or about 20% to about 55%, about 25% to about 55%, about 30% to about 55%, about 35% to about 55%%, about 40% to about 55%, about 45% to about 55%, about 50% to about 60%, about 55% to about 60%; or about 20% to about 50%, about 25% to about 50%, about 30% to about 50%, about 35% to about 50%,about 40% to about 50%, about 45% to about 50%, all percentages by weight of the total composition. acrylamide

[0023] Useful acrylamide materials have the general formula CH2=CR1C(O)NR2R3, where R1, R2 and R3 are independently selected from H; C1-10alkyl; C1-10alkyl comprising one or more functional groups selected from alkoxy, carbonyl, halogen and hydroxyl; or R2 and R3 together can form a saturated 4 to 6 member heterocyclic ring comprising N, C and optionally one other heteroatom as ring members. Some useful acrylamides are available from KJ Chemicals Corporation in Japan. In one preferred embodiment the of the acrylamide, R1 is H or methyl and R2 and R3 are each ethyl.

[0024] In some embodiments acrylamides having an OSHA toxicity rating such as NN-dimethyl acrylamide, are not used in the adhesive composition. vinyl cyclic amide

[0025] Useful vinyl cyclic amide materials include an aliphatic ring having a ring nitrogen atom bonded to two ring carbon atoms and a vinyl group pendant from the aliphatic ring. The vinyl cyclic amide material can have a one or more C1-10 alkyl groups pendant from one or more ring atoms and / or heteroatoms either as a ring atom or pendant from a ring atom. In one preferred embodiment the vinyl cyclic amide includes a 5 member aliphatic ring with a nitrogen atom and an oxygen atom as ring members, a2024P00004 pendant alkyl group. a pendant O atom and a pendant vinyl group. One useful commercially available vinyl cyclic amide is 3-ethenyl-5-methyl-1,3-oxazolidin-2-one.

[0026] In some embodiments vinyl cyclic amides having an OSHA health hazard rating, such as 4-acryloylmorpholine, n vinyl caprolactam, and n vinyl pyrrolidine, are not used in the adhesive composition. acrylamide to vinyl cyclic amide ratio

[0027] Surprisingly, use of the acrylamide and the vinyl cyclic amide in certain ratios provides improved bond strength compared to use of the acrylamide or vinyl cyclic amide alone. Ratios of the acrylamide / vinyl amide of about 0.5 / 1 to 1 / 0.5 based on wt.% of the acrylamide and vinyl cyclic amide in the composition seem to provide surprisingly improved strength compared to the same levels of acrylamide or vinyl cyclic amide alone. Photoinitiators

[0028] Photoinitiators useful in the present invention include, but are not limited to UV initiators, visible initiators, or a combination of UV and visible initiators covering the range of 200 to 500 nm. In one aspect of the present invention, the photoinitiator may be a polymeric structure to which is attached at least one chromophore that is excited by radiation in the UV light or visible light range.

[0029] A variety of UV initiators may be employed in any of the inventive compositions. UV initiators are generally effective in the 200 to 400 nm range, and particularly in the portion of the spectrum that borders on the invisible light and the visible portion just beyond this, e.g. > 200 nm to about 390 nm.

[0030] Among the useful initiators that will respond to UV radiation to initiate and induce curing of the (meth)acryl functionalized curable component include, but are not limited to, benzophenone and substituted benzophenones, acetophenone and substituted acetophenones, benzoin and its alkyl esters, xanthone and substituted xanthones, phosphine oxides, diethoxyacetophenone, benzoin methylether, benzoin ethylether, benzoin isopropylether, diethoxyxanthone, chlorothioxanthone, N-2024P00004 methyldiethanol-amine-benzophenone, 2-hydroxy-2methyl-1-phenyl-propan-1-one, 2- benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone and mixtures thereof.

[0031] Examples of such UV initiators include initiators available commercially from IGM Resins under the “OMNIRAD” (formerly “IRGACURE”) and “DAROCUR” trade names, specifically "OMNIRAD" 184 (1-hydroxycyclohexylphenylketone), 907 (2-methyl- 1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one), 369 (2-benzyl-2 - N,Ndimethylamino-1-(4-morpholinophenyl)-1-butanone), 500(the combination of 1- hydroxcyclohexyl phenylketone and benzophenone), 651(2,2-dimethoxy-2- phenylacetophenone), 1700 (the combination of bis(2,6-dimethoxybenzoyl-2,4,4- trimethylpentyl) phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one), 819 [bis(2,4,6,6-trimethylbenzoylphenyl phosphine oxide], “DAROCUR” 1173 (2-hydroxy-2- methyl-1-phenyl-1-propane) 4265 (the combination of 2,4,6-trimethylbenzoyldiphenyl- phosphineoxide and 2-hydroxy-2-methyl-1phenyl-propan-1-one); and 2,4,6- trimethylbenzoyldiphenylphosphine oxide (commercially available as LUCIRIN TPO from BASF Corp.).

[0032] Visible light initiators suitable for use in the present invention include, but are not limited to, camphorquinone peroxyester initiators, 9-fluorene carboxylic acid peroxyesters, visible light [blue] photoinitiators, d1-camphorquinone, “IRGACURE” 784DC (photoinitiator based on substituted titanocenes), and combinations thereof.

[0033] Any of the aforementioned photoinitiators may be used in the compositions of the invention in amounts of about 0.2% to about 5%, and desirably about 0.5% to about 3% by weight of the total composition. Optional Additives

[0034] The composition can optionally comprise a functional (meth)acrylate monomer. The functional (meth)acrylate monomer can be singly functional comprising a single reactive (meth)acrylate moiety or polyfunctional having two or three or more functional (meth)acrylate moieties.

[0035] Polyfunctional (meth)acrylate monomers include low molecular weight (meth)acrylate monomers and polyether (meth)acrylate monomers. Useful poly- functional polyether(meth)acrylate monomers may be selected from the group2024P00004 consisting of polyethylene glycol dimethylacrylate (PEG200 DMA), dipropylene glycol diacrylate, triethylene glycol di-(meth)acrylate, trimethylol propane tri(meth)acrylate, tetrahydrodicyclopentadienyl(meth)acrylate, ethoxylated trimethylol propane triacrylate (“ETTA”), triethylene glycol diacrylate and triethylene glycol dimethacrylate (“TRIEGMA”)and combinations thereof. In one aspect of the invention, polyether (meth)acrylate monomers with an average molecular weight above a certain range may be selected. In one aspect of the invention, polyether (meth)acrylate monomers with an average molecular weight of equal to or greater than 300 are desirable.

[0036] In some embodiments the photo-curable compositions may optionally include other functional low molecular weight (meth)acrylate monomers. These (meth)acrylate monomers can be used, for example, to tailor a specific property of the uncured composition or cured reaction products of the composition. In some embodiments the low molecular weight (meth)acrylate monomers, are monofunctional to limit cross- linking of the composition. If extractable material content is a concern care must be taken not to add low molecular weight (meth)acrylate monomers that would create or increase the potential for extractable material to be present subsequent to cure.

[0037] In some embodiments it may be desirable to have none, or mere trace amounts of, or nearly undetectable amounts of, (meth)acrylate monomer extractables. This can be accomplished by not using, or limiting the amount of, low molecular weight (meth)acrylate monomers in the composition. In other applications the amount of (meth)acrylate monomer extractables will be of lesser concern, allowing use of more low molecular weight (meth)acrylate monomers. The low molecular weight (meth)acrylate monomers do not take the place of the caprolactone-based polyurethane (meth)acrylate oligomer or the functional (meth)acrylate monomer.

[0038] Low molecular weight (meth)acrylate monomers include molecules having one or two or three or more functional (meth)acrylate moieties and a molecular weight of 500 or less, more usually 400 or less and more typically 250 or less or 150 or less. Low molecular weight (meth)acrylate monomers include mono-functional monomers such as hydroxyethyl(meth)acrylate (HEA or HEMA), Hydroxypropyl(meth)acrylate (HPA or HPMA), isobornyl(meth)acrylate (IBOA or IBOMA). As indicated, these monomers will not take the place of the required oligomer, but if present in minor2024P00004 amounts may be acceptable for certain applications and if the final cured compositions show substantially low or are essentially free extractable components. Keeping this caveat in mind, other conventional (meth)acrylate monomers may be incorporated as desired to achieve specific properties.

[0039] Additional low molecular weight (meth)acrylate monomers include, but are not limited to, (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, tolyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2- hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2- aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, (meth)acrylic acid-ethylene oxide adduct, trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2- perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2- perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2- perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate. In an aspect of the present invention, the (meth)acrylate monomer is polyethylene glycol diacrylate, such as SR 259 (polyethylene glycol (200) diacrylate from Sartomer). Suitable multifunctional (meth)acrylates include, but are not limited to, polyethylene glycol di (meth)acrylates, desirably triethyleneglycol di(meth)acrylate, hydroxypropyl(meth)acrylate, bisphenol-A di(meth)acrylates, such as ethoxylated bisphenol-A (meth)acrylate (“EBIPA” OR “EBIPMA”), and tetrahydrofuran(meth)acrylates and di(meth)acrylates, citronellyl acrylate and citronellyl methacrylate, hexanediol di(meth)acrylate (“HDDA” or “HDDMA”), trimethylol propane tri(meth)acrylate, tetrahydrodicyclopentadienyl(meth)acrylate, ethoxylated trimethylol propane triacrylate (“ETTA”), triethylene glycol diacrylate and triethylene glycol dimethacrylate (“TRIEGMA”).2024P00004

[0040] The (meth)acrylate monomers may be present in amounts of about 5%, about 10%, about 15%, about 20%, about 25% to about 30%; all percentages based on the weight of the total composition.

[0041] The composition can optionally comprise a catalyst in amounts useful in cure of the adhesive composition. Among the useful catalysts include organometallic catalysts. The organometallic catalysts desirably include stannous octoate, dibutyltin dilaurate and dibutyltin diacetate. One particularly desirable catalyst is dibutyltin dilaurate (DBTL).

[0042] For example, useful amounts of a catalyst include about 0.01 percent by weight to about 1.0 percent by weight of the total composition, and desirably in amounts of about 0.01 percent by weight to about 0.05 percent by weight of the total composition.

[0043] Suitable fillers include organic and inorganic ones. Inorganics include silica, silicate, alumina, barium sulphate, calcium carbonate, calcium fluoride, carbon black, clays, diatomaceous earth, feldspar, ferromagnetics, fly ash, glass bubbles, glass fibers, gypsum, jute fiber, kaolin, lingnocellulosics, magnesium hydroxide, mica, microcrystalline cellulose, powdered metals, quartz, starch, talc, titanium dioxide, wood flour, wood fibers, and combinations thereof. Organic fillers include thermoplastic polymers, for example polymeric microspheres, polyvinylacetates, polyolefins, and nylon fibers.

[0044] Fillers are optional and if used may be incorporated into any of the compositions for desired properties and as such may be present in the amount of about 0.1% to about 30%, and desirably about 5% to about 20% percent by weight of the total composition.

[0045] The composition can optionally comprise an organic rheology modifier to adjust rheology of the uncured adhesive composition. If used, organic rheology modifier may be present in the amount of about 1% to about 10%, or 1% to about 5% percent by weight of the total composition.

[0046] The composition can optionally comprise a stabilizer to increase stability of the adhesive composition during storage. If used, stabilizer may be present in the2024P00004 amount of about 0.1% to about 2%, and desirably about 0.5% to about 1% percent by weight of the total composition.

[0047] The composition can optionally comprise an antioxidant to increase stability of the adhesive composition during storage. If used, antioxidant may be present in the amount of about 0.1% to about 2%, and desirably about 0.5% to about 1% percent by weight of the total composition.

[0048] The composition can optionally comprise a defoamer to lessen foaming of the adhesive composition during manufacture, packing and use. If used, the defoamer may be present in the amount of about 0.1% to about 2%, and desirably about 0.5% to about 1% percent by weight of the total composition.

[0049] The composition can optionally comprise further additives, such as, but not limited to, fluorescence additives, fillers, photosensitizers, coloring agents, accelerators, adhesion promoters, pigments and combinations thereof.

[0050] The synthesized photo-curable (meth)acrylate compositions of the present invention may be used as adhesives for substrates and exhibit particularly desirable bond strengths on plastic substrates.

[0051] Articles of manufacture which can be bonded with the disclosed adhesive compositions include epoxy and reinforced epoxy composites such as such as G10 / FR4 glass fiber epoxy composite, polycarbonate (PC), polyvinylchloride (PVC), acrylonitrile butadiene styrene (ABS), thermoplastic urethane (TPU), (meth)acrylate and (meth)acrylate copolymers. In some embodiments the photo-curable (meth)acrylate compositions of this invention show workable viscosity ranges (especially low viscosities relative to readily available comparable commercial products. The disclosed compositions are not expected to provide optimum bond strength for metal, paper or ceramic substrates.

[0052] In one aspect of the invention, there is included an article of manufacture which incorporates the inventive compositions and the process of incorporating the compositions in such an article. For example, an article of manufacture is contemplated which includes a first plastic substrate surface and a second plastic substrate surface, said first and second substrate surfaces adhesively joined by cured reaction products of2024P00004 the disclosed photocurable compositions. The plastic substrates enumerated herein are contemplated for such articles.

[0053] The photo-curable compositions of this invention find a balance of workable relatively low viscosities, excellent physical properties such as adhesion strength, and in some embodiments low or no detectable extractability (or leaching out) of harmful / hazardous compounds, for example low molecular weight (meth)acrylate monomers.

[0054] The photo-curable compositions generally have a Shore D hardness of about 30 to about 90.

[0055] In one aspect of the invention, the photo-curable composition has a viscosity of about 150 to about 50,000 Cps and desirably 150 to about 10,000 Cps.

[0056] In one aspect of the present invention, the photo-curable composition may be cured using a radiation source, such as a bulb or LED that produces visible or UV light. Curing would also be possible using exposure to electrons from a beam source. In one embodiment cured reaction products of these compositions have a PC / epoxy composite lap shear strength of 5 to 15 Mpa.

[0057] In general, the foregoing description is provided for exemplary and illustrative purposes; the present invention is not necessarily limited thereto. Rather, those skilled in the art will appreciate that additional modifications, as well as adaptations for particular circumstances, will fall within the scope of the invention as herein shown and described and of the claims appended hereto. EXAMPLES Testing Methods Examples were evaluated according to the testing conditions described herein below. Viscosity Viscosities were measured at 25°C and a shear rate of 10s-1using a cone and plate rheometer (Anton Paar).2024P00004 Shore D hardness Shore D samples were measured based on ASTM D2240. The light curable composition was placed between two plastic sheets with a 1 mm thick spacer, and light cured for 10 seconds on each side using Henkel EQ CL20 LED Flood 405 nm with a light intensity of 1.2w / cm2. The cured sheet was cut into 20 mm long and 10 mm wide rectangular specimen and hardness was measured. Lap shear strength Tensile lap shear was tested per ASTM D3163. Four types of lap shear substrates were tested: Polyvinylchloride (PVC, 25 x 100 x 1.5mm) from ThyssenKrupp Material NA, Polycarbonate (PC, 25 x 100 x 3 mm) UV Trans Grade from Kariega, a glass fiber reinforced epoxy substrate available as Epoxy FR-4 or G-10 Epoxy Glass (25 x 100 x 1.5 mm) from Curbell Plastics, and Acrylonitrile butadiene styrene (ABS, 25 x 100 x 1.5 mm) from ThyssenKrupp Material NA. The substrates were cleaned with isopropyl alcohol to remove dirt and oils. The adhesive compositions were applied to a portion of the substrate surface and then covered with UV Trans Grade PC to create a bonding area of 25x12.7mm (1x0.5inch) with zero gap. The bonding area was then light cured for 30 seconds on top of the PC substrate using Henkel EQ CL20 LED Flood 405 nm with light intensity of 1.0 w / cm2. The lap shear samples were tested on a lap shear pulling machine with a pulling speed of 0.08 inch / minute. The tensile strength at maximum load was recorded. The provided strengths for each composition are an average of results for 6 lap shear specimens. Materials The following materials were used in the examples: EBECRYL 8811 is a polyurethane (meth)acrylate oligomer available from Allnex. PHOTOMER 6019 is a polyurethane (meth)acrylate oligomer available from IGM. BISOMER PEG200DMA is a polyethylene glycol dimethacrylate 200Mw available from Geo Specialty. SR508 is the methacrylate monomer dipropylene glycol diacrylate. NNDEAA is the acrylamide NN-diethyl acrylamide. VCA1 is the vinyl cyclic amide 3-ethenyl-5-methyl-1,3-oxazolidin-2-one.2024P00004 Omnirad TPO-L is a photoinitiator available from IGM. Omnirad 819 is a photoinitiator available from IGM. Examples Examples were prepared by combining and mixing compositions as shown in the below Table. Amounts are in wt.% Properties of these compositions are also shown in the Table. Example 1 inv A comp B comp 2 inv C comp D comp EBECRYL 8811 45 45 45 PHOTOMER 6019 50 50 50 SR508 23 23 23 PEG200DMA 24 24 24 NNDEAA 15 30 12 24 VCA1 15 30 12 24 OMNIRAD 819 1 1 1 1 1 1 OMNIRAD TPO-L 1 1 1 1 1 1 Total 100 100 100 100 100 100 viscosity (Cp @ 25C) 308 249 403 189 155 243 Shore D hardness 74 71 77 84 82 84 PC / FR4 lap shear 7.70 6.08 6.23 5.7 4.67 4.40 strength (Mpa)

Claims

2024P00004 CLAIMS:

1. A photocurable composition comprising: a urethane(meth)acrylate oligomer; an acrylamide; a vinyl cyclic amide; and a photoinitiator; wherein the acrylamide and the vinyl cyclic amide are present at a ratio of about 0.5 / 1 to 1 / 0.5 based on wt.% of the acrylamide and vinyl cyclic amide in the composition.

2. The photocurable composition of claim 1 wherein cured reaction products of the composition have a PC / FR4 lap shear strength of at least 4 Mpa.

3. The photocurable composition of any one of the above claims further comprising a polyfunctional polyether (meth)acrylate monomer.

4. The photocurable composition of any one of the above claims further comprising a polyfunctional polyether (meth)acrylate monomer selected from the group consisting of polyethylene glycol dimethylacrylate (PEG200 DMA), dipropylene glycol diacrylate and combinations thereof.

5. The photocurable composition of any one of the above claims, wherein the composition further comprises a low molecular weight (meth)acrylate monomer.

6. The photocurable composition of any one of the above claims, wherein the urethane (meth)acrylate oligomer is present in the amount of about 20% to about 60% by weight; preferably about 30% to about 50% by weight, of the total composition.2024P00004 7. The photocurable composition of any one of the above claims, wherein the acrylamide is present in the amount of about 5% to about 40% by weight; preferably about 5% to about 20% by weight.

8. The photocurable composition of any one of the above claims, wherein the uncured photo-curable composition has a viscosity of about 150 Cps to about 10,000 Cps.

9. The photocurable composition of any one of the above claims, further comprising a monofunctional (meth)acrylate monomer and / or a polyfunctional (meth)acrylate monomer.

10. The photocurable composition of any one of the above claims, wherein the composition further comprises an additive.

11. An article of manufacture comprising: a first substrate surface; and the adhesive composition any one of claims 1 to 13 disposed on the first substrate surface.

12. Use of the composition of any one of claims 1 to 16 as an adhesive, sealant or coating.