Photocurable acrylate adhesive for plastic bonding

Abstract

The present invention relates to a photocurable (meth)acrylate composition that, when cured, has high wrap shear strength and / or low extractable or undetectable amounts of acrylic monomers or monomer components listed in the GHS list. The composition comprises a novel caprolactone-based polyurethane (meth)acrylate oligomer and is used in the formulation of a photocurable composition useful for bonding substrates, particularly plastic substrates. The composition is suitable for use as an adhesive, sealant, or coating agent for many substrates.

Description

[Technical Field]

[0001] background field In one embodiment, the present invention relates to a photocurable (meth)acrylate composition that yields a low amount of hazardous and / or harmful acrylic monomer compounds upon curing. The composition comprises a caprolactone-based polyurethane (meth)acrylate oligomer, one or more bifunctional methacrylate monomers, and a photoinitiator. The composition is suitable for use as an ink, adhesive, sealant, or coating agent. [Background technology]

[0002] Overview of related technologies Urethane acrylate compounds are commonly used in light-curable adhesives, inks, coatings, and sealants. Light-cured or photo-cured compositions are those that can be cured using visible light or ultraviolet (UV) radiation. These compositions ideally have a balanced molecular weight and viscosity for effective application. Furthermore, reactive acrylic diluents are often added to improve workability. These acrylic monomers are generally low-molecular-weight polar compounds and may not be fully incorporated into the polymerized composition, potentially leaching over time and causing harmful and / or hazardous exposure to human health.

[0003] For example, commercially available (meth)acrylate-based photocurable compositions generally contain only low molecular weight acrylates such as isobornyl (meth)acrylate (IBOA, MW 222.32) and N,N-dimethylacetamide (N,N'-DMA, MW 87.12), or epoxy monomers that may be undesirable for certain applications. Although these compositions undergo rapid photocuring and crosslinking, unreacted monomers, or monomer components and impurities, may still leach out or be extracted under certain conditions, potentially posing problems in specific applications.

[0004] One way to address this problem is to use monomers with higher molecular weights, but this approach generally leads to reduced reactivity and often negatively affects properties such as viscosity and adhesion strength to various substrates. Therefore, most commercially available photocurable acrylate products use low molecular weight (meth)acrylate monomers, and their Safety Data Sheet (SDS) profiles require corrosiveness and hazard indications based on the Globally Harmonized System (GHS). [Overview of the Initiative]

[0005] It is advantageous to find a (meth)acrylate-based photocurable composition that has a workable viscosity and, preferably, high adhesive strength and / or a low amount of unreacted, extractable (meth)acrylate monomers after curing. The present invention provides such a solution by forming a photocurable oligomer component using monomers that are not considered chemically hazardous, and in some embodiments, eliminates or substantially minimizes other potential extractables from the final photocurable composition. GHS is a set of rules administered by the United Nations for classifying and communicating chemical hazards. This composition is not a pressure-sensitive adhesive and would not be suitable for use as such. [Modes for carrying out the invention]

[0006] One aspect of the present invention is, a) Caprolactone-based polyurethane (meth)acrylate oligomers; b) Monofunctional or polyfunctional (meth)acrylate monomers; and c) Photoinitiator It includes a photocurable composition containing [the specified ingredient]. One aspect of the present invention is, a) Caprolactone-based polyurethane (meth)acrylate oligomers; b) Polyfunctional polyether (meth)acrylate monomers; and c) Photoinitiator; A photocurable composition comprising, The resulting photocurable composition contains a photocurable composition that, upon photocuring, exhibits a low amount of extractable (unreacted) components.

[0007] One aspect of the present invention is, a) Caprolactone-based polyurethane (meth)acrylate oligomers present in an amount of approximately 20% to 60% of the total weight of the composition; b) Polyfunctional polyether (meth)acrylate monomers present in an amount of about 10% to about 60% of the total weight of the composition; and c) A photoinitiator present in an amount of approximately 0.2% to approximately 5% of the total weight of the composition; A photocurable composition comprising, The ratio of the oligomer / polyfunctional polyether (meth)acrylate may be in the range of approximately 30 / 70 to approximately 70 / 30, approximately 35 / 65 to approximately 65 / 35, approximately 45 / 55 to approximately 55 / 45, approximately 40 / 60 to approximately 60 / 40, and approximately 50 / 50; and, The resulting photocurable composition includes a photocurable composition that, upon photocuring, substantially does not exhibit any detectable extractable (unreacted) components.

[0008] Another aspect of the present invention is: a) A step of preparing a caprolactone-based polyurethane (meth)acrylate oligomer by reacting a mono(meth)acrylate monomer containing a hydroxyl group with hexamethylene diisocyanate (HDI) isocyanurate; and, b) A step of combining the reaction product from step a) with a polyfunctional polyether (meth)acrylate monomer and a photoinitiator. including, The process includes preparing a photocurable composition.

[0009] Another aspect of the present invention includes a method for forming an adhesive, coating, or sealant by applying the photocurable composition thus formed to a substrate and exposing it to UV or visible light to crosslink and cure the composition. The invention also includes a manufactured product incorporating the composition as a layer, coating, bond, adhesive, or sealant.

[0010] Detailed explanation definition As used herein, the term “oligomer” means a relatively low molecular weight polymer compound in which at least two monomer units are bonded together. Preferably, the oligomer contains 2 to 1,000 monomer units bonded together, and more preferably, it contains 2 to 300 monomer units, or 2 to 200 monomer units, or 2 to 100 monomer units, or 2 to 50 monomer units, or 2 to 40 monomer units, or 2 to 30 monomer units, or 2 to 20 monomer units, or 2 to 10 monomer units, or 1 to 5 monomer units bonded together.

[0011] As used herein, the term "(meth)acrylic" refers to acrylic, methacrylic, or any combination thereof. Similarly, the term "(meth)acryloxy" refers to acryloxy, methacryloxy, or any combination thereof; the term "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or any combination thereof; the term "(meth)acrylate" refers to acrylate, methacrylate, or any combination thereof; and the term "(meth)acrylamide" refers to acrylamide, methacrylamide, or any combination thereof. The number of (meth)acrylic groups in the (meth)acrylate usable in the present invention is not particularly limited and may be one or more.

[0012] The terms “extracted,” “extractable,” or “extractables” refer to unreacted monomers, monomer residues, or monomer components (e.g., monomer impurities) that are extractable after curing or leach out over time after curing. Extractable components may be present in trace amounts, as long as they are not in quantities that would be considered harmful to human health or cause sensitization, but it is desirable that no extractables be detected in the compositions of the present invention.

[0013] The term "molecular weight (M.W.)" means the average molecular weight (average weight fraction) based on the weight fraction of molecules in the sample. Molecular weight data can be obtained by gel permeation chromatography (GPC) calibrated against polystyrene standards according to known methods, such as DIN 55672-1:2007-08. The number average molecular weight Mn can be measured by a similar method.

[0014] The present invention provides a (meth)acrylate-containing composition that can be rapidly photocured. In one embodiment, the composition comprises a mono(meth)acrylate monomer having one or more hydroxyl end groups, a caprolactone-based polyurethane (meth)acrylate oligomer produced by the reaction of hexamethylene diisocyanate (HDI) isocyanurate, a functional (meth)acrylate monomer, and a photoinitiator. The oligomers used in the composition have relatively low viscosities themselves, facilitating the formation of the desired low viscosity in the photocurable composition to which they are added.

[0015] Useful oligomers The caprolactone-based polyurethane (meth)acrylate oligomer comprises a reaction product of a hydroxyl group-containing mono(meth)acrylate monomer containing a caprolactone-containing (meth)acrylate monomer and hexamethylene diisocyanate (HDI) isocyanurate or biuret. Examples of this oligomer include Capa-1 (the reaction product of HDI isocyanurate and hydroxy-terminated polycaprolactone acrylate) and Capa-2 (the reaction product of HDI biuret and hydroxy-terminated polycaprolactone acrylate).

[0016]

Chemical formula

[0017]

Chemical formula

[0018] Mono(meth)acrylate monomers, such as caprolactone-containing monomers, are labeled with the GHS. However, these materials react completely in the cured product and do not contain any extractable components.

[0019] Caprolactone-based polyurethane (meth)acrylate oligomers are present in amounts of approximately 20% to approximately 60%, approximately 25% to approximately 60%, approximately 30% to approximately 60%, approximately 35% to approximately 60%, approximately 40% to approximately 60%, approximately 45% to approximately 60%, approximately 50% to approximately 60%, approximately 55% to approximately 60%; or approximately 20% to approximately 55%, approximately 25% to approximately 55%, approximately 30% to approximately 55%, approximately 35% to approximately 55%, approximately 40% to approximately 55%, approximately 45% to approximately 55%, approximately 50% to approximately 60%, and approximately 55% to approximately 60% (all percentages are relative to the total weight of the composition).

[0020] Functional (meth)acrylate monomers This composition contains a functional (meth)acrylate monomer. The functional (meth)acrylate monomer is preferably polyfunctional, having two or more functional (meth)acrylate substructures. The functional (meth)acrylate monomer includes low molecular weight polyfunctional (meth)acrylate monomers and polyfunctional polyether (meth)acrylate monomers.

[0021] Useful polyfunctional polyether (meth)acrylate monomers may be selected from the group consisting of polyethylene glycol dimethyl acrylate (PEG200 DMA), dipropylene glycol diacrylate, triethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetrahydrodicyclopentadienyl(meth)acrylate, ethoxylated trimethylolpropane triacrylate ("ETTA"), triethylene glycol diacrylate, and triethylene glycol dimethacrylate ("TRIEGMA"), as well as combinations thereof. In one embodiment of the present invention, a polyfunctional polyether (meth)acrylate monomer with an average molecular weight exceeding a specific range may be selected. In one embodiment of the present invention, a polyfunctional polyether (meth)acrylate monomer with an average molecular weight of 300 or more is desirable.

[0022] The polyfunctional polyether (meth)acrylate monomer may be present in amounts of about 10% to about 60%, about 15% to about 60%, 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%; or about 10% to about 55%, about 15% to about 55%, about 20% to about 55%, 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 55% (all percentages are based on the total weight of the composition).

[0023] As shown in the examples, various ratios of oligomer to polyfunctional polyether (meth)acrylate offer specific advantages with respect to the viscosity of the photocurable compositions and their physical properties when cured. For example, the oligomer / polyfunctional polyether (meth)acrylate ratio may range from about 30 / 70 to about 70 / 30 (e.g., 28 / 72 to 72 / 28), about 35 / 65 to about 65 / 35, about 45 / 55 to about 55 / 45, about 40 / 60 to about 60 / 40, and about 50 / 50. Higher ratios of oligomer to polyfunctional polyether (meth)acrylate resulted in lower viscosity and higher tensile strength on plastic substrates. Conversely, higher ratios of polyfunctional polyether (meth)acrylate to oligomer resulted in higher viscosity and lower tensile strength.

[0024] Photoinitiator Useful photoinitiators in the present invention include, but are not limited to, UV initiators, visible light initiators, or combinations of UV initiators and visible light initiators. In one embodiment of the present invention, the photoinitiator may be a polymer structure to which at least one chromophore excited by UV light or radiation in the visible light region is bound.

[0025] Various UV initiators can be used in any of the compositions of the present invention. UV initiators are generally effective in the range of 200 to 400 nm, particularly in the spectral portion adjacent to invisible light and slightly beyond visible light, for example, from above 200 nm to about 390 nm.

[0026] Useful initiators for initiating and inducing the curing of (meth)acrylic functional curable components in response to UV radiation include, but are not limited to, benzophenone and substituted benzophenones, acetophenone and substituted acetophenones, benzoin and its alkyl esters, xanthones and substituted xanthones, phosphine oxides, diethoxyacetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxyxanthone, chlorothioxanthone, N-methyldiethanolamine-benzophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, and mixtures thereof.

[0027] Examples of such UV initiators include those marketed by IGM Resins under the trademarks "OMNIRAD" (formerly "IRGACURE") and "DAROCUR," specifically "OMNIRAD" 184 (1-hydroxycyclohexyl phenyl ketone), 907 (2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one), 369 (2-benzyl-2-N,N-dimethylamino-1-(4-morpholinophenyl)-1-butanone), 500 (combination of 1-hydroxycyclohexyl phenyl ketone and benzophenone), 651 (2,2-dimethoxy-2-phenylacetophenone), and 1700 (bis(2, Examples include a combination of 6-dimethoxybenzoyl-2,4,4-trimethylpentyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 819[bis(2,4,6,6-trimethylbenzoylphenylphosphine oxide)], "DAROCUR" 1173 (2-hydroxy-2-methyl-1-phenyl-1-propane), 4265 (a combination of 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one); and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (commercially available from BASF as LUCIRIN TPO).

[0028] Suitable visible light initiators for use in the present invention include, but are not limited to, camphorquinone peroxyester initiators, 9-fluorenecarboxylic acid peroxyesters, visible light [blue] initiators, d1-camphorquinone, "IRGACURE" 784DC (a photoinitiator based on substituted titanocene), and combinations thereof.

[0029] Any of the above photoinitiators may be used in the composition of the present invention in an amount of about 0.2% to about 5%, preferably about 0.5% to about 3%, relative to the total weight of the composition.

[0030] Any additives In some embodiments, the photocurable composition may optionally contain, in addition to, caprolactone-based polyurethane (meth)acrylate oligomers or functional (meth)acrylate monomers, functional low molecular weight (meth)acrylate monomers, which are different from those therefrom. These additional (meth)acrylate monomers may be used, for example, to modulate specific properties of the uncured composition or the curing reaction product of the composition. In some embodiments, the low molecular weight (meth)acrylate monomers are monofunctional to limit crosslinking of the composition. If extractable material content is a concern, care should be taken not to add low molecular weight (meth)acrylate monomers that may create or increase the possibility of extractable material being present after curing.

[0031] In some embodiments, it may be desirable that the composition contains no (meth)acrylate monomer extractables, or only trace amounts, or virtually undetectable amounts. This can be achieved by not using low molecular weight (meth)acrylate monomers in the composition, or by limiting their amount. In other applications, the amount of (meth)acrylate monomer extractables is not as critical, and therefore a larger amount of low molecular weight (meth)acrylate monomers can be used. Low molecular weight (meth)acrylate monomers are not a substitute for caprolactone-based polyurethane (meth)acrylate oligomers or functional (meth)acrylate monomers.

[0032] Low molecular weight (meth)acrylate monomers include molecules having one, two, or three or more functional (meth)acrylate substructures and having a molecular weight of 500 or less, more commonly 400 or less, more typically 250 or 150 or less. Low molecular weight (meth)acrylate monomers include monofunctional monomers such as hydroxyethyl (meth)acrylate (HEA or HEMA), hydroxypropyl (meth)acrylate (HPA or HPMA), and isobornyl (meth)acrylate (IBOA or IBOMA). As stated above, these monomers are not substitutes for the required oligomers and polyfunctional polyether (meth)acrylates, but may be acceptable in certain applications when present in trace amounts, and may also be acceptable if the final cured composition contains substantially few or essentially no extractable components. With this caution in mind, other conventional acrylic monomers may be incorporated as desired to achieve specific properties.

[0033] 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, and 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-hydroxyethyl(meth)acrylate, 2-hydroxyethyl Examples include cypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, (meth)acrylate-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 one embodiment of the present invention, the (meth)acrylate monomer is polyethylene glycol diacrylate, for example, SR 259 (Sartomer, polyethylene glycol (200) diacrylate).Suitable polyfunctional (meth)acrylates include, but are not limited to, polyethylene glycol di(meth)acrylate, preferably triethylene glycol di(meth)acrylate, hydroxypropyl (meth)acrylate, bisphenol-A di(meth)acrylate (e.g., ethoxylated bisphenol-A (meth)acrylate ("EBIPA" or "EBIPMA")), and tetrahydrofuran (meth)acrylate and di(meth)acrylate, citronellyl acrylate and citronellyl methacrylate, hexanediol di(meth)acrylate ("HDDA" or "HDDMA"), trimethylolpropane tri(meth)acrylate, tetrahydrodicyclopentadienyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate ("ETTA"), triethylene glycol diacrylate and triethylene glycol dimethacrylate ("TRIEGMA").

[0034] The catalyst may be optionally, but preferably, incorporated into the composition of the present invention in an amount useful for oligomer formation, and / or incorporated into the entire polymer composition.

[0035] Useful catalysts include organometallic catalysts. Preferably, organometallic catalysts include tin octanoate, dibutyltin dilaurate, and dibutyltin diacetate. One particularly desirable catalyst is dibutyltin dilaurate (DBTL).

[0036] For example, a useful amount of catalyst is approximately 0.01% to 1.0% of the total weight of the composition, and preferably approximately 0.01% to 0.05% of the total weight of the composition.

[0037] Any additives, such as but not limited to fluorescent additives, fillers, rheological modifiers, photosensitizers, colorants, accelerators, adhesion promoters, defoamers, stabilizers, antioxidants, and pigments, as well as combinations thereof, may be included in the compositions of the Disclosure.

[0038] Suitable fillers include organic and inorganic fillers. Inorganic fillers include silica, silicate, alumina, barium sulfate, calcium carbonate, calcium fluoride, carbon black, clay, diatomaceous earth, feldspar, ferromagnetic materials, fly ash, glass bubbles, glass fibers, gypsum, jute fibers, kaolin, lignocellulosics, magnesium hydroxide, mica, microcrystalline cellulose, metal powders, quartz, starch, talc, titanium dioxide, wood powder, wood fibers, and combinations thereof. Organic fillers include thermoplastic polymers, such as polymer microspheres, polyvinyl acetate, polyolefins, and nylon fibers.

[0039] Fillers are optional and, if used, may be incorporated into any composition for desired properties, and in this way may be present in an amount of about 0.1% to about 30%, preferably about 5% to about 20%, of the total weight of the composition.

[0040] Optionally, an organic rheological modifier may be incorporated into any of the compositions of the present invention for desired properties, so as to be present in an amount of about 1% to about 10%, preferably about 2% to about 6%, of the total weight of the composition.

[0041] Optionally, stabilizers may be incorporated into any of the compositions of the present invention for desired properties, and in this manner may be present in an amount of about 0.1% to about 2%, preferably about 0.5% to about 1%, relative to the total weight of the composition.

[0042] Optionally, an antioxidant may be incorporated into any of the compositions of the present invention for desired properties, and in this manner may be present in an amount of about 0.1% to about 2%, preferably about 0.5% to about 1%, relative to the total weight of the composition.

[0043] Optionally, an antifoaming agent may be incorporated into any of the compositions of the present invention for desired properties, and in this manner may be present in an amount of about 0.1% to about 2%, preferably about 0.5% to about 1%, relative to the total weight of the composition.

[0044] The synthesized photocurable (meth)acrylate composition of the present invention may be used as an adhesive, coating agent, ink, and sealant for substrates, and exhibits particularly excellent properties for plastic substrates.

[0045] Various plastics are useful for use with the compositions of the present invention, including, for example, polycarbonate (PC), polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), thermoplastic urethane (TPU), (meth)acrylate and (meth)acrylate copolymers, epoxy and reinforced epoxy composites (e.g., G10 / FR4 glass fiber epoxy composites). In some embodiments, the photocurable (meth)acrylate compositions of the present invention exhibit a workable viscosity range (particularly lower viscosity compared to readily available equivalent commercial products) and show good adhesion to plastic substrates such as polycarbonate (PC), polyvinyl chloride (PVC), and acrylonitrile butadiene styrene (ABS), as well as substrates commonly used in electronic devices such as G10 / FR4 glass epoxy composites. The compositions of this disclosure are not expected to provide optimal adhesive strength to metal, paper, or ceramic substrates.

[0046] One aspect of the present invention includes a manufactured article incorporating the composition of the present invention, and a process for incorporating the composition into such a manufactured article. For example, a manufactured article is envisioned that includes a first plastic substrate surface and a second plastic or metal substrate surface, wherein the first and second substrate surfaces are bonded together by forming a bond using the photocurable composition of the present invention. The plastic substrates listed herein are envisioned for such a manufactured article.

[0047] The photocurable compositions of the present invention strike a balance between a relatively low viscosity that allows for workability, excellent physical properties such as adhesive strength, and, in some embodiments, low or no extractability (or leaching) of harmful / hazardous compounds such as low molecular weight (meth)acrylate monomers.

[0048] The photocurable composition typically has a Shore D hardness of about 50 to about 95, 50 to about 85, 50 to about 80, 50 to about 75, 50 to about 70, 50 to about 65, 50 to about 60; or about 55 to about 95, about 55 to about 90, about 55 to about 85, about 55 to about 80, about 55 to about 75, about 55 to about 70, about 55 to about 65, about 55 to about 60, about 60 to about 95, about 60 to about 90, about 60 to about 85, about 60 to about 80, about 60 to about 75, 60-approximately 70, approximately 60-approximately 6; or 65-approximately 95, 65-approximately 90, 65-approximately 85, 65-approximately 80, 65-approximately 75, 65-approximately 70; or 70-approximately 95, or 70-approximately 90, or 70-approximately 85, or 70-approximately 80, or 70-approximately 75, or 70-approximately 65, or 70-approximately 60; or 75-approximately 95, 75-approximately 90, 75-approximately 85, 75-approximately 80; or 80-approximately 95, 80-approximately 90, or 85-approximately 95.

[0049] The photocurable composition of the present invention has a thixotropy index (TI) of about 2 to about 10, preferably about 2 to about 7 (1s). -1 cps / 10s -1 It may also be cps in . The term "thixotropy index" as used herein refers to the rate at which the curing composition is cured. -1 Viscosity (centipoise) at (sec-1) and curing rate of the composition at 10 seconds -1 (Sec-1) Ratio of viscosity (centipoise (cps)) to (1s -1 viscosity at / 10s -1 This refers to viscosity in a given region. Viscosity may be measured using known methods, such as a cone-plate rheometer, a parallel-plate rheometer, or a rotational viscometer such as a Brookfield viscometer.

[0050] In one embodiment of the present invention, the photocurable composition has a viscosity of about 200 to about 10,000 Cps, 300 to about 7,000 Cps, and preferably 500 to about 5,000 Cps.

[0051] In one embodiment of the present invention, the photocurable composition may be cured using a radiation source such as a light bulb or LED that generates visible light or UV light. Curing can also be performed by irradiation with an electron beam from a beam source.

[0052] In one embodiment, the curing reaction products of these compositions have a PC / PC wrap shear strength of 4 MPa and / or a PC / PVC wrap shear strength of 5 MPa. These strengths are remarkable, as similar compositions have not been able to achieve these strength levels.

[0053] In one embodiment, the curing reaction product of the composition has an extractable amount of low molecular weight (meth)acrylate monomer below a desired limit. In some applications where exposure is a concern, a weight ratio of 50 ppm or less, or 25 ppm or less, or 10 ppm or less, or undetectable is desirable. In other applications, higher limits for extractable low molecular weight (meth)acrylate monomer, e.g., 100 ppm or less, or 250 ppm or less, or 500 ppm or less, or 1,000 ppm or less, may be acceptable. In some applications, the level of extractable low molecular weight (meth)acrylate monomer may not be a concern.

[0054] In general, the above description is provided for illustrative and explanatory purposes only; the present invention is not necessarily limited thereto. Rather, those skilled in the art will understand that additional modifications and adaptations to specific circumstances are included within the scope of the inventions shown and described herein and the claims appended thereto. [Examples]

[0055] Test method Examples 1-6 were evaluated according to the test conditions described below.

[0056] viscosity Viscosity was measured using a cone-plate rheometer (Anton Paar) at a shear rate of 1s. -1 and 10s -1It was measured at. The thixotropy index (TI) was calculated as the ratio of the viscosity at 1 s -1 to the viscosity at 10 s -1 .

[0057] Shore D hardness The Shore D sample was measured based on ASTM D2240. The photocurable composition was placed between two plastic sheets using a 1-mm-thick spacer, and each side was photocured for 10 seconds using a Henkel EQ CL20 LED flood 405 nm with a light intensity of 1.2 W / cm 2 . The cured sheet was cut into rectangular test pieces with a length of 20 mm and a width of 10 mm.

[0058] Lapp shear strength The tensile lap shear test was performed in accordance with ASTM D3163. Four types of lap shear substrates were tested: polyvinyl chloride (PVC, 25×100×1.5 mm) manufactured by ThyssenKrupp Material NA, UV transgrade polycarbonate (PC, 25×100×3 mm) manufactured by Kariega, a glass fiber reinforced epoxy substrate (25×100×1.5 mm) available as Epoxy FR-4 or G-10 epoxy glass manufactured by Curbell Plastics, and acrylonitrile butadiene styrene (ABS, 25×100×1.5 mm) manufactured by ThyssenKrupp Material NA. The substrates were washed with isopropyl alcohol to remove dirt and oil. The composition of the present invention was applied as an adhesive to a part of the substrate surface, and then covered with UV transgrade PC to form a 25×12.7 mm (1×0.5 inch) bonding area without gaps. Then, the bonding area was photocured for 30 seconds from above the PC substrate using a Henkel EQ CL20 LED flood 405 nm with a light intensity of 1.0 W / cm 2 . The lap shear samples were tested on a lap shear tensile tester at a tensile speed of 0.08 inches / minute. The tensile strength at the maximum load was recorded. The strength shown for each composition is the average of the results of 6 lap shear test pieces.

[0059] Preparation and testing of (meth)acrylate monomer extraction test samples. Approximately 4-5 g of the photocurable composition (both the comparative example and the inventive example shown below) is placed between two 6 x 8 mm polyethylene (PE) pieces cut from a 0.75 mm thick sheet, and then exposed to light at a light intensity of 1.0 W / cm². 2 Each surface was photocured for 20 seconds using a Henkel EQ CL20 LED flood at 405 nm. The PE film was removed, and the cured adhesive was cut into strips of approximately 1 x 2 cm and placed in a 3-dram glass vial. Strips were added to the vial until the nominal aggregate weight reached 2 grams. The vial was filled with 7 ml of acetone, and 250 μl of 2500 ppm decane internal standard solution was added. The vial was placed in an incubator and kept at 38°C for 24 hours.

[0060] The amount of (meth)acrylate monomer was measured using a GC / MS instrument (e.g., Agilent 7890B GC, 5977A MSD, and 7650 ALS) with an Agilent HP-5MS column (30 m × 0.25 mm, 0.25 microns). The sample was introduced into the GC by 25:1 split injection. The GC oven was held at 40°C for 4 minutes, then increased to 280°C at 10°C / min, and held for 10 minutes. The column flow rate was kept constant at 1 ml / min, and the retention time for decane was 10.4 minutes. The mass spectrometer was operated in 70 eV electron shock mode, with a mass scanning range of 35 to 550 amu. Total ion chromatography (TIC) was generally used for quantification, but extraction ion treatment may be used for complex chromatograms where co-elution of the analyte occurs, or when sensitivity is to be improved. In this case, m / z 57 was used as the characteristic ion for decane, and the characteristic ion for the analyte was selected based on its mass spectrum. Selected ion monitoring (SIM) may be used to improve sensitivity. Generally, levels below 50 ppm are considered acceptable in sensitive applications.

[0061] The amount of analyte extracted from the sample was calculated using the formula Cx = ((AxCis) / Ais) × (Vs / Wt.). In the formula, Cx = Concentration of the analyte extracted from the film (μg / g) Cis = concentration of internal standard (μg / ml) Ax = Peak area of ​​the analyte. Ais = internal standard peak area, Vs = Volume of extraction solvent in 3 drum vials (ml), Wt. = Total weight (g) of extracted cured film.

[0062] material The photocurable acrylate material used in all examples:

[0063] [Table 1]

[0064] Example 1 Oligomer synthesis procedure : DBDTL and HDI (Desmodur N3300 or N3200) were added to the mixing jar in the amounts shown in Table 1 and thoroughly mixed with a spatula. Next, hydroxy monoacrylate (HEA, HPA, HBA, or CAPA) was slowly added to the mixing jar in the amounts shown in Table 1 for each reaction. The mixing jar was then placed in an oven at 70-80°C and the reaction was allowed to proceed with stirring. The presence of the isocyanate (NCO) peak was measured by FTIR to determine when all NCO groups had reacted. The reaction was continued, and the NCO peak was periodically checked by FTIR every 30 minutes until the NCO peak was no longer detectable.

[0065] Table 2 shows the viscosity of each of the eight synthesized oligomers. The two oligomers according to the invention (Example 1 (HDI-CAPA1) and Example 2 (HDI-CAPA2)) produced from HDI and CAPA have significantly lower viscosities (37,745 and 33,041) than those produced in Examples A to F, which are other oligomers (oligomers that do not contain CAPA).

[0066] [Table 2]

[0067] [Table 3]

[0068] Example 2 The photocurable acrylate compositions were prepared by separately mixing eight synthesized oligomers (Examples 1.1 to 1.8) with polyethylene glycol dimethacrylate monomer PEG200DMA and a photoinitiator, according to the formulations shown in Table 3. The properties (including viscosity, hardness, and lapping shear strength) of these compositions and their curing reaction products are summarized in Table 4. The compositions relating to the invention are shown in Examples 3 and 4. Compositions G to L were comparative examples.

[0069] [Table 4]

[0070] [Table 5]

[0071] Examples 3 and 4 of the invention, which included oligomers HDI-CAPA-1 and HDI-CAPA-2, showed relatively lower viscosity and curing hardness compared to Examples G to L. As shown in the table, the shear strength of polycarbonate / polycarbonate (PC / PC) and polycarbonate / polyvinyl chloride (PC / PVC) wraps using the compositions of the invention was significantly higher than that of the other comparative examples. Furthermore, no low molecular weight (meth)acrylate monomer extractables were detected in Examples 3 and 4.

[0072] Table 5 shows two additional bond strengths using Examples 3 and 4 of the photocured compositions of the invention. As shown in Table 5, the bond strengths in PC / ABS and PC / epoxy G10 FR4 are all equivalent to the desirable, higher lap shear strengths of PC / PC and PC / PVC.

[0073] [Table 6]

[0074] Comparative Example 3 Photocurable acrylate compositions were prepared using two commercially available aliphatic urethane triacrylate oligomers (Photomer 6019 and Photomer 6008) and one commercially available polyester urethane acrylate. These were each mixed separately with polyethylene glycol dimethacrylate monomer PEG200DMA and a photoinitiator according to the formulations in Table 6. The oligomers Photomer 6019 and Photomer 6008, and the polyester urethane acrylate were not synthesized using caprolactone monomers. The properties of these compositions (including viscosity, hardness, and lap shear strength) are summarized in Table 7.

[0075] [Table 7]

[0076] [Table 8]

[0077] Comparative Example M had a hardness similar to Examples 3 and 4 of the invention, but with slightly lower viscosity. However, the shear strength of the PC / PC and PC / PVC wraps for Comparative Example M was significantly lower than that of Examples 3 and 4 of the invention. Comparative Examples N and O had a hardness similar to Examples 3 and 4 of the invention, but with significantly higher viscosity. Their PC / PC and PC / PVC wrap shear strengths were significantly lower than those of Examples 3 and 4 of the invention.

[0078] Comparative Example 4 The photocurable acrylate compositions were prepared by separately mixing three additional (non-CAPA) monomers with HDI-CAPA-1 and HDI-CAPA-2 and a photoinitiator, respectively, according to the formulations in Table 8. The properties of these compositions (including viscosity, hardness, and lap shear strength) are summarized in Table 9.

[0079] [Table 9]

[0080] [Table 10]

[0081] Surprisingly, Examples 5 and 6, using polyethylene glycol diacrylate (PEGDA) monomer, exhibit significantly lower hardness and undesirably lower PC / PVC wrap shear strength compared to Examples 3 and 4, which use PEG200DMA. Examples 7 and 8, using trimethylene glycol dimethacrylate (TEGDMA) monomer, exhibit similar hardness and PC / PVC wrap shear strength to Examples 3 and 4, which use PEG200DMA. Furthermore, no low molecular weight (meth)acrylate monomer extractables were detected in Examples 5, 6, 7, and 8.

[0082] Examples 9 and 10 show that when polyfunctional polyether (meth)acrylate monomers are substituted with monofunctional monomers such as IBOA, the hardness decreases, but the PC / PVC wrap shear strength is comparable to that of Examples 3 and 4, indicating that polyfunctional polyether (meth)acrylate monomers are necessary to achieve all desired properties. Examples 9 and 10 also show significant levels of extractable low molecular weight (meth)acrylate monomers and impurity compounds of those low molecular weight (meth)acrylate monomers.

[0083] Example 5 The compositions according to the invention were prepared by mixing oligomers HDI-CAPA 1 and HDI-CAPA-2 with the bifunctional monomer PEG200DMA in various mixing ratios. These compositions were each mixed separately with the same amount of photoinitiator according to the formulations in Table 10. The properties of these compositions (including viscosity, hardness, and lapping shear strength) are summarized in Table 11.

[0084] [Table 11]

[0085] [Table 12]

[0086] Examples 5.1 and 5.2, with an oligomer-to-monomer weight percentage mixing ratio of 70 / 28, showed higher viscosity and lower hardness values ​​than the compositions in Examples 2.7, 2.8, 5.3, and 5.4, where the ratio was approximately 50 / 50 or 30 / 70, respectively. All of these examples showed similar PC / PVC wrap shear strength when tested.

Claims

1. a) Caprolactone-based polyurethane (meth)acrylate oligomers; b) (meth)acrylate monomers; and c) Photoinitiator; A photocurable composition comprising, A photocurable composition wherein the curing reaction product of the composition has a PC / PC wrap shear strength of 4 MPa and / or a PC / PVC wrap shear strength of 5 MPa.

2. The photocurable composition according to claim 1, wherein when the resulting photocured composition is tested using a (meth)acrylate monomer extraction test, it substantially does not exhibit low molecular weight (meth)acrylate monomer extractables.

3. The photocurable composition according to claim 1 or 2, wherein the (meth)acrylate monomer is a polyfunctional polyether (meth)acrylate monomer.

4. The composition according to any one of claims 1 to 3, wherein the caprolactone-based polyurethane (meth)acrylate oligomer comprises a reaction product of a mono(meth)acrylate monomer containing a hydroxyl group and hexamethylene diisocyanate (HDI) isocyanurate, or a reaction product of a mono(meth)acrylate monomer containing a hydroxyl group and hexamethylene diisocyanate (HDI) biuret.

5. The composition according to any one of claims 1 to 4, wherein the caprolactone-based polyurethane (meth)acrylate oligomer is selected from the group consisting of CAPA-1, CAPA-2, or a combination thereof, and its structure is shown below: 【Chemistry 1】 【Chemistry 2】 。

6. The composition according to any one of claims 1 to 5, further comprising a low molecular weight (meth)acrylate monomer.

7. The composition according to any one of claims 1 to 6, wherein the composition further comprises 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, and combinations thereof.

8. The composition according to any one of claims 1 to 7, wherein the caprolactone-based polyurethane (meth)acrylate oligomer is present in an amount of about 20% to about 60% of the total weight of the composition.

9. The composition according to any one of claims 1 to 8, wherein the (meth)acrylate monomer is a polyfunctional polyether (meth)acrylate monomer selected from the group consisting of polyethylene glycol dimethyl acrylate (PEG200 DMA), dipropylene glycol diacrylate, and combinations thereof.

10. The composition according to any one of claims 1 to 9, wherein the (meth)acrylate monomer is a polyfunctional polyether (meth)acrylate monomer and is present in an amount of about 10% to about 60% of the total weight of the composition.

11. The composition according to any one of claims 1 to 10, wherein the uncured photocurable composition has a viscosity of about 200 Cps to about 10,000 Cps.

12. The composition according to any one of claims 1 to 11, wherein the (meth)acrylate monomer is a monofunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer.

13. The composition according to any one of claims 1 to 12, wherein the composition further comprises an additive selected from fluorescent additives, fillers, rheological modifiers, photosensitizers, colorants, accelerators, adhesion promoters, defoamers, stabilizers, antioxidants, and pigments.

14. First substrate surface; and The adhesive composition according to any one of claims 1 to 13, disposed on the surface of the first substrate. Products containing the above.

15. A step of providing a mono(meth)acrylate monomer containing a hydroxyl group; A step of providing a polyisocyanate selected from hexamethylene diisocyanate (HDI) isocyanurate, hexamethylene diisocyanate (HDI) biuret, or a combination thereof; A step of reacting the mono(meth)acrylate monomer containing the hydroxyl group with the polyisocyanate to form a caprolactone-based polyurethane (meth)acrylate oligomer; and A step of combining the caprolactone-based polyurethane (meth)acrylate oligomer with a polyfunctional (meth)acrylate monomer and a photoinitiator; A process for preparing a photocurable composition comprising: A process for preparing a photocurable composition in which the curing reaction product of the composition has a PC / PC wrap shear strength of 4 MPa and / or a PC / PVC wrap shear strength of 5 MPa.

16. The process according to claim 15, wherein the polyfunctional (meth)acrylate monomer is selected from polyethylene glycol dimethyl acrylate (PEG200 DMA), dipropylene glycol diacrylate, and combinations thereof.

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

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