Photocurable (meth)acrylate composition

Abstract

Photocurable (meth)acrylate compositions for forming features on the surface of membranes, particularly membranes used in osmosis and reverse osmosis applications such as membrane filters.

Description

[Technical Field]

[0001] The present invention relates to curable (meth)acrylate compositions comprising isocyanate-functional compounds, and methods of making and using such compositions. More specifically, the present invention relates to photocurable (meth)acrylate compositions for forming features on the surface of membranes, particularly membranes used in osmosis and reverse osmosis applications, such as membrane filters. [Background technology]

[0002] Curable compositions have been widely used in sealing, adhesive, coating, and potting applications, to name a few. The type of backbone and curable groups is generally selected with reference to the particular end use and environment in which it is intended to be used. Polymers with varying degrees of unsaturation and other functional crosslinking groups have been used.

[0003] Commonly used adhesives (i.e., curable compositions) for bonding and spacing reverse osmosis (RO) membranes are two-part, room-temperature-curing polyurethanes or epoxies. The two parts must be mixed and applied to form a part prior to gelation, which is undesirable for some applications. Photocurable acrylates containing (meth)acrylate-terminated polybutadiene have been disclosed for membrane fold protection, but bonding to membranes has not been reported. Polybutadiene acrylate oligomers generally have poor adhesion to many substrates. Photocurable acrylates containing polyether urethane acrylate resins are known to have excellent hydrolytic stability, but bonding to RO membranes is difficult in alkaline solutions.

[0004] Adhesion promoters act at the interface between an organic adhesive and an organic or inorganic substrate, strengthening the bond between the two materials. Often, the two materials have different compatibility, chemical reactivity, surface properties, and thermal expansion coefficients, making it difficult to form a strong adhesive bond between them. Adhesion promoters act to chemically and physically bind these dissimilar materials into a strong cohesive bond. Adhesion promoters can impart resistance to environmental and other damaging forces, such as heat and moisture, which often act on the bond site and destroy its strength.

[0005] Adhesion promoters are often molecules with reactive functional groups at both ends of the molecule. Functional groups known to enhance adhesion of polymers to surfaces include phosphate and carboxylic acids (metal adhesion) and silyl ethers (glass / silyl adhesion), which hydrolyze to give reactive Si-OH bonds. Monomers with functional groups such as acid, amine, and hydroxyl can provide polymer adhesion to many substrates. While various adhesion promoters have been used to improve adhesion to substrates such as glass, plastic, and metal, their use for adhesion to filtration membranes is unknown. Dual-cure compositions with isocyanate and acrylate end groups have been used in hot melt and conformal coatings, but not to enhance adhesion to membranes.

[0006] Furthermore, even if adequate adhesion between the curable composition and the membrane surface is initially achieved, materials, such as spacer features, adhered to the membrane surface are necessary to maintain good adhesion to the membrane after curing and during membrane use and maintenance. For example, RO membrane use and maintenance requires exposing the membrane surface and its adhered features / spacers to an aqueous environment. In particular, cleaning the membrane often requires exposing the membrane to acidic and basic aqueous solutions. Upon contact with water, especially under acidic and alkaline solutions, the features formed by the cured composition can deteriorate, resulting in loss of mass, mechanical strength, and adhesion to the membrane during use and maintenance.

[0007] There is a need for photocurable (meth)acrylate compositions and methods for using such compositions to create features on the surface of a film that allow for good adhesion of the cured composition to the film surface and for maintaining good adhesion, mass, and mechanical strength of the cured composition during subsequent use and maintenance of the film. Summary of the Invention [Means for solving the problem]

[0008] The present invention provides a photocurable composition comprising: a) a (meth)acrylate-functionalized urethane component; b) a (meth)acrylate monomer; and c) a photoinitiator; the (meth)acrylate-functionalized urethane component comprises isocyanate functionality, and / or the photocurable composition further comprises d) an isocyanate-functionalized adhesion promoter; the curable composition, when deposited on a polyamide surface of a substrate and exposed to UV or visible light, forms a cured reaction product on the polyamide surface of the substrate; The cured reaction product comprises: 1) Substrate failure after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about one week, and / or 2) Substrate failure after immersion in basic aqueous (pH=12.5) conditions at a temperature of about 50°C for about one week, and / or 3) exhibiting adhesion to a substrate polyamide surface characterized by substrate failure after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50° C. for about one week; The substrate is a reverse osmosis membrane with a polyamide surface, and a photocurable composition is provided.

[0009] Another aspect of the present invention provides a composite film structure comprising: a) a film comprising at least one surface; and b) a cured reaction product of the photocurable composition described above disposed on at least a portion of at least one surface of the film.

[0010] In a further aspect of the present invention, a photopolymerization process can be performed using a method comprising the steps of: a) providing a curable composition comprising: i) a (meth)acrylate-functionalized urethane component; ii) a (meth)acrylate monomer; and iii) a photoinitiator; wherein the (meth)acrylate-functionalized urethane component comprises isocyanate functionality; and / or the photocurable composition further comprises iv) an isocyanate-functionalized adhesion promoter; b) exposing said curable composition to a UV or visible light source to form a cured reaction product, the curable composition, when deposited on a polyamide surface of a substrate and exposed to UV or visible light, forms a cured reaction product on the polyamide surface of the substrate; The cured reaction product comprises: 1) Substrate failure after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about one week, and / or 2) Substrate failure after immersion in basic aqueous (pH=12.5) conditions at a temperature of about 50°C for about one week, and / or 3) exhibiting adhesion to a substrate polyamide surface characterized by substrate failure after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50° C. for about one week; wherein the substrate is a reverse osmosis membrane with a polyamide surface. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention provides a photocurable composition comprising: a) a (meth)acrylate-functionalized urethane component; b) a (meth)acrylate monomer; and c) a photoinitiator; the (meth)acrylate-functionalized urethane component comprises isocyanate functionality, and / or the photocurable composition further comprises d) an isocyanate-functionalized adhesion promoter; the curable composition, when deposited on a polyamide surface of a substrate and exposed to UV or visible light, forms a cured reaction product on the polyamide surface of the substrate; The cured reaction product comprises: 1) Substrate failure after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about one week, and / or 2) Substrate failure after immersion in basic aqueous (pH=12.5) conditions at a temperature of about 50°C for about one week, and / or 3) exhibiting adhesion to a substrate polyamide surface characterized by substrate failure after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50° C. for about one week; For photocurable compositions, the substrate is a reverse osmosis membrane with a polyamide surface.

[0012] In one embodiment of the present invention, the curable composition has a viscosity of about 10,000 to about 100,000, or about 20,000 to about 80,000 centipoise (at 25°C, 10 s -1 ) viscosity.

[0013] In one aspect of the invention, the curable composition has an optimized rheology that is effectively balanced to allow sufficient thixotropy to facilitate deposition, while maintaining its physical structure after deposition and before curing. As used herein, "thixotropy" means that a material becomes less viscous when subjected to stress (e.g., mixing and shaking), and more viscous in the absence of such stress (e.g., at rest).

[0014] In further aspects of the present invention, the curable composition has a thixotropy index of from about 1.5 to about 10, or from about 2 to about 8. As used herein, "thixotropy index" refers to the thixotropy index of from about 1.5 to about 10, or from about 2 to about 8. -1 Viscosity (centipoise) of the curable composition at a rate of 10 s -1 The ratio of the viscosity (centipoise) of the curable composition at the rate of -1 Viscosity at / 10s -1 Viscosity may be determined by known methods, for example, using a cone-plate rheometer, a parallel-plate rheometer, or a rotational viscometer such as a Brookfield viscometer.

[0015] In one embodiment of the present invention, the (meth)acrylate-functionalized polyetherurethane component is a polyetherurethane acrylate oligomer. In this embodiment of the present invention, the (meth)acrylate-functionalized polyetherurethane component may be synthesized by reacting a diisocyanate with a polyether polyol to produce an isocyanate-terminated urethane. The isocyanate-terminated urethane is then reacted with a hydroxy-terminated acrylate to provide acrylate groups at the ends of the oligomer. If the terminal isocyanate does not completely react with the hydroxy acrylate, the isocyanate remains in the structure as a reactive group in addition to the acrylate end group.

[0016] Examples of suitable urethane acrylate oligomers include, but are not limited to, aliphatic urethane acrylates, such as Ebecryl 230, 264, 265, 270, 1258, 1290, 4100, 4200, 4265, 4666, 4738, 4740, 4827, 4858, 4858, 4859, 5129, 8210, 8301, 8415, 8620, 8604, 8605, 8702, 8807, 8800-20R (all from Allnex), BR582E8, BR-930D, and BR-304. 2, BR3471 (all from Dymax), Genomer 4297, 4302, 4312, 4316, 4425, 4622, 4230, 4217, 4267 (all from Rahn), Photomer 6891, 4184, 6008, 6230, 6645, 6692 (all from IGM), CN9002, 9004, 9178, 940, 989, 996, 9011, 980, 991 (all from Sartomer), and combinations thereof. In an embodiment of the present invention, the urethane acrylate oligomer is Ebecryl 880-20R (Allnex), Ebecryl 8807 (Allnex), BR582E8 (Dymax), or combinations thereof.

[0017] In further embodiments of the present invention, the (meth)acrylate-functionalized polyetherurethane component is present in an amount of from about 20% to about 60% by weight, or from about 30% to about 50% by weight, based on the total weight of the curable composition.

[0018] In another embodiment of the present invention, the (meth)acrylate-functionalized polyetherurethane component further includes isocyanate functionality. Suitable (meth)acrylate-functionalized polyetherurethane components including isocyanate functionality include, but are not limited to, Ebecryl 4141, 4250, 4396, 4397, 4510, and 4765 (all from Allnex), and combinations thereof.

[0019] Suitable (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-hydroxy Dipropyl (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 one embodiment of the invention, the (meth)acrylate monomer is a polyethylene glycol diacrylate, such as SR259 (polyethylene glycol (200) diacrylate from Sartomer).Suitable multifunctional (meth)acrylates include, but are not limited to, polyethylene glycol di(meth)acrylate, desirably triethylene glycol di(meth)acrylate, hydroxypropyl (meth)acrylate, bisphenol-A di(meth)acrylate such as 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").

[0020] In one embodiment of the invention, the (meth)acrylate monomer is present in an amount of from about 10% to about 50% by weight, or from about 20% to about 40% by weight, based on the total weight of the curable composition.

[0021] In further aspects of the invention, the (meth)acrylate monomer has a viscosity of less than about 1,000 cps or less than about 500 cps.

[0022] In one embodiment of the present invention, the isocyanate-functionalized adhesion promoter is an isocyanate-terminated urethane acrylate, an isocyanate-terminated aliphatic prepolymer, or a combination thereof. Suitable isocyanate-terminated urethane acrylates include, but are not limited to, Ebecryl 4141, 4250, 4396, 4397, 4510, and 4765 (all from Ornex), and combinations thereof. Suitable isocyanate-terminated aliphatic prepolymers include, but are not limited to, Desmodur XP2599 (from Covestro), Desmodur VPLS2371 (from Covestro), or combinations thereof.

[0023] In embodiments of the present invention, the isocyanate-functionalized adhesion promoter is present in an amount of from about 5% to about 60% by weight, or from about 10% to about 30% by weight, based on the total weight of the curable composition.

[0024] In embodiments of the present invention, the curable composition is a photocurable or light curable composition, i.e., curable using light, such as visible light or ultraviolet (UV) light. In embodiments of the present invention, the curable composition may be cured using a light source, such as a bulb or LED, that generates visible or UV light.

[0025] In further aspects of the invention, the photoinitiator may be a UV initiator, a visible initiator, or a combination of UV and visible initiators. In one aspect of the invention, the photoinitiator is a polymeric structure having attached thereto at least one chromophore that is excited by radiation in the UV or visible light range.

[0026] A variety of UV initiators may be used, and are generally effective in the 200-400 nm range, particularly in that portion of the spectrum adjacent to the invisible and slightly beyond in the visible portion, e.g., >200 nm to about 390 nm.

[0027] Initiators that respond to UV radiation and initiate and induce cure of the (meth)acrylic-functionalized curable component that are useful in the present invention include, but are not limited to, benzophenone and substituted benzophenones, acetophenone and substituted acetophenones, benzoin and its alkyl esters, xanthone and substituted xanthone, phosphine oxide, diethoxy-acetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxyxanthone, chloro-thio-xanthone, N-methyldiethanol-amine-benzophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, and mixtures thereof.

[0028] Examples of such UV initiators include "Omnirad" (formerly "Irgacure") and "Darocur" trade names, particularly "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 (1-hydroxycyclohexyl phenyl ketone and benzophenone combination), 651 (2,2-dimethoxy-2-phenylacetophenone), 1700 (bis(2,6-dimethoxybenzoyl-2,4,4-trimethylpentyl) ) phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one), and 819 [bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide], as well as "Darocur" 1173 (2-hydroxy-2-methyl-1-phenyl-1-propane) and 4265 (2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one), and initiators commercially available from IGM Resins as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (commercially available from BASF as Lucirin TPO). Of course, combinations of these materials may also be used herein. Of course, some of these photoinitiators classified herein as UV photoinitiators have tailing absorption into the visible range and straddle the line between UV and visible light-cured initiators, but are nonetheless understood to be included herein as part of the present invention.

[0029] Suitable initiators for use in the present invention that initiate and induce cure in response to visible light include camphorquinone peroxyester initiator, 9-fluorenecarboxylic acid peroxyester, visible light [blue] photoinitiator, d1-camphorquinone, "Irgacure" 784DC (a substituted titanocene-based photoinitiator), and combinations thereof.

[0030] Other suitable photoinitiator systems include those disclosed in each of the following patents or publications, each of which is incorporated herein by reference in its entirety: U.S. Pat. No. 4,505,793 to Tamoto et al., incorporated herein by reference, discloses a photoinitiator comprising a combination of a 3-keto-substituted coumarin compound and an active halogen compound. Several exemplary compounds are disclosed. Such photoinitiators cure upon exposure to light having a wavelength in the range of about 180 nm to 600 nm. U.S. Pat. No. 4,258,123 to Nagashima et al., incorporated herein by reference, discloses a photosensitive resin composition comprising an initiator component that generates free radicals upon exposure to actinic radiation. Such components include various triazine compounds, as more fully described herein.

[0031] Additional useful components are disclosed in the following documents, which are incorporated herein by reference: European Patent Publication No. EP 0 369 645 A1 discloses a three-part photoinitiator system including a trihalomethyl-substituted s-triazine, a sensitizer compound capable of absorbing radiation in the range of about 300 to 1000 nm, and an electron donor. Exemplary sensitizer compounds are disclosed, including ketones, coumarin dyes, xanthene dyes, 3H-xanthene-3-one dyes, acridine dyes, thiazole dyes, thiazine dyes, oxazine dyes, azine dyes, aminoketone dyes, methane and polymethine dyes, porphyrins, aromatic polycyclic hydrocarbons, p-substituted aminostyryl ketone compounds, aminotriarylmethanes, merocyanines, squarylium dyes, and pyridinium dyes. Exemplary donors are also disclosed, including amines, amides, ethers, urea, ferrocene, sulfinic acids and their salts, ferrocyanide salts, ascorbic acid and its salts, dithiocarbamic acids and their salts, xanthates, ethylenediaminetetraacetic acid salts, and tetraphenylboronic acid salts. These initiators are sensitive to both UV and visible light.

[0032] Additional useful components are disclosed in the following documents, which are incorporated herein by reference: European Patent Publication No. EP 0 563 925 A1 discloses photoinitiators including a sensitizer compound capable of absorbing radiation in the range of approximately 250 to 1000 nm and a 2-aryl-4,6-bis(trichloromethyl)-1,3,5-triazine. Exemplary sensitizer compounds disclosed include cyanine dyes, merocyanine dyes, coumarin dyes, ketocoumarin dyes, (thio)xanthene dyes, acridine dyes, thiazole dyes, thiazine dyes, oxazine dyes, azine dyes, aminoketone dyes, squarylium dyes, pyridinium dyes, (thia)pyrylium dyes, porphyrin dyes, triarylmethane dyes, (poly)methane dyes, aminostyryl compounds, and polycyclic aromatic hydrocarbons. These photoinitiators are sensitive to UV and visible light.

[0033] U.S. Patent No. 5,395,862 to Neckers et al., incorporated herein by reference, discloses fluorone photoinitiators sensitive to visible light. These fluorone initiator systems also include coinitiators capable of accepting electrons from excited fluorone species. Exemplary coinitiators include onium salts, nitrohalomethanes, and diazosulfones. U.S. Patent No. 5,451,343 to Neckers et al., incorporated herein by reference, discloses fluorones and pyronin-Y derivatives as initiators that absorb light at wavelengths greater than 350 nm. U.S. Patent No. 5,454,676 to Palazotto et al., incorporated herein by reference, discloses a three-part photoinitiator system that cures under UV or visible light. The three-part system includes an arylidonium salt, a sensitizer compound, and an electron donor. Exemplary iodonium salts include diphenyliodonium salts. Exemplary sensitizers and electron donors for use in the three-part system are also disclosed. Furthermore, the sensitizer can absorb light in the range of about 300 to about 1000 nm.

[0034] In further embodiments of the present invention, the photoinitiator is present in an amount of from about 0.2 wt % to about 5 wt %, or from about 1 wt % to about 3 wt %, based on the total weight of the curable composition.

[0035] In a further embodiment of the present invention, the curable composition may further comprise a filler. Suitable fillers include organic and inorganic fillers. Inorganic fillers include silica, silicates, alumina, asbestos, barium sulfate, calcium carbonate, calcium fluoride, carbon black, clay, diatomaceous earth, feldspar, ferromagnetic materials, fly ash, glass fiber, gypsum, jute fiber, kaolin, linocellulose, magnesium hydroxide, mica, microcrystalline cellulose, powdered metals, quartz, starch, talc, titanium dioxide, wood flour, wood fiber, and combinations thereof. Organic fillers include thermoplastic polymers such as polyvinyl acetate, polyolefins, and nylon fiber.

[0036] In one embodiment of the invention, the filler is present in an amount of about 2% to about 40% by weight, or about 5% to about 30% by weight, based on the total weight of the hardenable composition.

[0037] Optional additives such as, but not limited to, coinitiators, stabilizers, rheology modifiers, antifoaming agents, inhibitors, oxygen scavengers, dyes, colorants, pigments, adhesion promoters, plasticizers, toughening agents, reinforcing agents, fluorescent agents, wetting agents, antioxidants, and combinations thereof may also be included in the compositions of the present invention.

[0038] The composite film structure of the present invention includes: a) a film comprising at least one surface; and b) a cured reaction product of the photocurable composition described above disposed on at least a portion of at least one surface of the film.

[0039] The method of producing the cured reaction product of the present invention comprises the steps of: a) providing a curable composition comprising: i) a (meth)acrylate-functionalized urethane component; ii) a (meth)acrylate monomer; and iii) a photoinitiator; the (meth)acrylate-functionalized urethane component comprises isocyanate functionality, and / or the photocurable composition further comprises iv) an isocyanate-functionalized adhesion promoter; b) exposing the curable composition to a UV or visible light source to form a cured reaction product; the curable composition, when deposited on a polyamide surface of a substrate and exposed to UV or visible light, forms a cured reaction product on the polyamide surface of the substrate; The cured reaction product comprises: 1) Substrate failure after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about one week, and / or 2) Substrate failure after immersion in basic aqueous (pH=12.5) conditions at a temperature of about 50°C for about one week, and / or 3) exhibiting adhesion to a substrate polyamide surface characterized by substrate failure after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50° C. for about one week; The substrate is a reverse osmosis membrane with a polyamide surface.

[0040] In embodiments of the present invention, the cured reaction product has a Shore D hardness of about 30 or greater, preferably about 30 to about 80 or about 35 to about 70.

[0041] In another embodiment of the composite membrane structure of the present invention, the cured reaction product adhesively bonds to at least a portion of at least one surface of the membrane.

[0042] In another aspect of the composite membrane structure of the present invention, the cured reaction product is disposed on at least a portion of at least one surface of the membrane in a predetermined pattern. In embodiments of the composite membrane structure of the present invention, the predetermined pattern is selected from the group consisting of stripes, waves, circles, ellipses, arcs, squares, rectangles, diamonds, pentagons, hexagons, stars, chevrons, random patterns, and combinations thereof.

[0043] In one embodiment of the present invention, a pattern is formed on the membrane surface by known methods, such as printing or depositing a curable composition on the membrane surface followed by curing the curable composition. The pattern formed on the membrane surface by the method of the present invention typically consists of a number of features formed from the cured reaction product. Generally, these features have physical properties suitable for providing spacing between overlying layers of the membrane. For example, these features may provide appropriate spacing between layers of a spiral reverse osmosis filtration membrane to optimize the operation, cleaning, and life of a reverse osmosis membrane element employing a membrane having these features. In one embodiment of the present invention, the pattern of features may have a size and shape sufficient to maintain appropriate membrane spacing and expose sufficient membrane surface to ensure efficient membrane operation.

[0044] Generally, the bond strength of an adhesive (e.g., a cured composition) to a substrate may be described by determining whether the adhesive or the substrate fails when the adhesive is subjected to increasing force and separated from the substrate. If the adhesive maintains its integrity and the substrate mechanically fails, this is considered substrate failure (SF). If the substrate remains intact and the adhesive mechanically fails, this is considered adhesive failure (AF).

[0045] As used herein, "substrate failure" means that when a curable composition of the present invention is cured on the polyamide surface of a reverse osmosis membrane as a substrate, as described below, and tested for adhesion to the substrate (or membrane), the substrate fails when force is applied, as opposed to the adhesive. In another aspect of the present invention, the substrate used to determine adhesion to the membrane (i.e., whether substrate failure occurs) is a reverse osmosis membrane having a polyamide surface, such as FFilmtec® Flat Sheet BW30LE.

[0046] For the curable compositions of the present invention, adhesion to a substrate (or film) involves 1) curing the curable composition to form beads of cured product adhered to the film surface and forcibly removing these beads from the film surface. If the film breaks, it is considered substrate failure (SF). If the film remains intact, it is considered adhesive failure (AF). A detailed description of an example of this test method is provided in the Examples section.

[0047] The surface onto which the curable composition is deposited may include the surface of any membrane suitable for application of the curable composition. In one embodiment of the present invention, the surface onto which the curable composition is deposited is a membrane surface. As used herein, "membrane" refers to a selective barrier that allows the passage of some substances while preventing the passage of other substances. In one embodiment of the present invention, the membrane is a filter membrane, i.e., a membrane for filtering substances from a liquid carrier such as water. Filter membranes include reverse osmosis membranes, forward osmosis membranes, microfiltration membranes, ultrafiltration membranes, and nanofiltration membranes. The feature consisting of the cured composition may be deposited on the active surface of the membrane, or the inactive surface of the membrane, or both.

[0048] Additionally, hydrophilic materials such as glycerol may be added to the membrane to maintain the membrane pore open. Additionally, antifouling agents such as polyethylene glycol may be employed in the membrane.

[0049] The isocyanate functional groups of the photocurable (meth)acrylate compositions of the present invention bond with reactive hydroxyl-functionalized moieties on the polyamide and / or membrane to form urethane chemical bonds that are stronger than the mechanical locking or hydrogen bond formation of compositions lacking isocyanate functionality.

[0050] In an embodiment of the present invention, the membrane surface is composed of polyamide and / or includes reactive hydroxyl-functionalized moieties.

[0051] In an embodiment of the present invention, the composite membrane structure of the present invention exhibits substrate failure after prolonged immersion in aqueous conditions at elevated temperatures. As used herein, "prolonged period" means about 0.5 weeks, about 1 week, about 2 weeks, about 3 weeks, about 4 weeks, about 5 weeks, or about 6 weeks. As used herein, "high temperature" means about 30°C or higher, about 35°C or higher, about 40°C or higher, about 45°C or higher, about 50°C or higher, about 55°C or higher, about 60°C or higher, or about 70°C or higher.

[0052] In embodiments of the present invention, aqueous conditions may include acidic aqueous conditions, basic aqueous conditions, and neutral aqueous conditions. As used herein, "acidic aqueous conditions" refers to aqueous conditions having a pH of about 3 or less, about 2.5 or less, about 2 or less, about 1.5 or less, or about 1 or less. As used herein, "basic aqueous conditions" refers to aqueous conditions having a pH of about 11 or more, about 11.5 or more, about 12 or more, about 12.5 or more, or about 13 or more. As used herein, "neutral aqueous conditions" refers to aqueous conditions having a pH of about 6 to about 8, or a pH of about 7. [Example]

[0053] In the examples below, the following ingredients were used:

[0054] [Table 1]

[0055] [Test method] In the examples below, the following test methods were employed.

[0056] (Viscosity and Thixotropy Index) A cone and plate rheometer (Anton Paar) was used to measure the shear rate of 1 s -1 and 10s -1 The viscosity was measured at 1 s -1 and 10s -1 The thixotropy index was calculated as the ratio of the viscosities of

[0057] (adhesion to membrane) The curable composition was applied to an RO membrane (Filmtec® Flat Sheet BW30LE) to form beads approximately 20 mils in diameter and 20 mils in height. The beads on the membrane had a density of 1.5 W / cm 2 It was immediately cured in 10 seconds using a 405nm LED light with an intensity of 1000.

[0058] The membranes with deposited beads of cured reaction product were immersed in aqueous solutions of different pH for various times at a temperature of 50°C. A solution of pH 1.5 was prepared by mixing 25 g of 37% hydrochloric acid solution with 975 g of distilled water. A solution of pH 8 was prepared by adding 0.084 g of sodium bicarbonate, 0.111 g of calcium chloride, and 0.045 g of 5% sodium hypochlorite to 1000 g of distilled water. A solution of pH 12.5 was prepared by adding 2 grams of sodium hydroxide to 1000 grams of distilled water.

[0059] The adhesion of the cured reaction product to the film was inspected before and after immersion by manually removing the beads from the film using a spatula. If the film breaks, it is considered a substrate failure (SF). If the film remains intact, it is considered an adhesive failure (AF).

[0060] (Shore D hardness) Shore D hardness was measured according to ASTM D2240. The tested material was placed between two PE films and covered with two glass plates to form a sheet with a thickness of 1 mm, and then 1.5 W / cm was applied to both sides of the glass plates. 2 The cured sheet was then cut into four pieces, stacked, and measured on a Shore hardness tester.

[0061] Comparative Example 1 - Curable composition without isocyanate-functional adhesion promoter Various photocurable formulations without the addition of isocyanate resin or isocyanate-functionalized adhesion promoter were formulated as shown in Table 2 below.

[0062] [Table 2]

[0063] These formulations were cured and tested for Shore hardness and adhesion to membranes, and the results are shown in Table 3.

[0064] [Table 3]

[0065] Prior to immersion in aqueous solutions, adhesion to the membrane for all formulations exhibited substrate failure (SF). After one week of immersion, Comparative Compositions 1.1-1.4 maintained SF adhesion in the pH 1.5 and pH 8 solutions. Comparative Composition 1.5 lost adhesion and exhibited AF in all three solutions. After immersion in the pH 12.5 solution, all compositions lost adhesion and exhibited AF.

[0066] Comparative Example 2 - Curable composition containing a conventional adhesion promoter Various photocurable formulations containing commonly used adhesion promoters were formulated as shown in Table 4 below. All compositions in this comparative example used Ebecryl 8807, the urethane acrylate oligomer used in Comparative Composition 1.2. Commonly used adhesion promoters were Photomer 4967, Dynasylan DAMO T, KBM5103, Kayama-PM2, NNDMA, and HPA. Comparative Composition 1.2 (without adhesion promoter) was included for comparison.

[0067] [Table 4]

[0068] These formulations were cured and tested for Shore hardness and adhesion to membranes, and the results are shown in Table 5.

[0069] [Table 5]

[0070] Prior to immersion in the aqueous solutions, adhesion to the membrane for all formulations showed substrate failure (SF). After one week of immersion in the pH 12.5 solution, all compositions lost adhesion and showed AF. Comparative Compositions 2.2, 2.3, and 2.4 maintained SF after immersion in the pH 1.5 and pH 8 solutions. However, Comparative Composition 2.5 lost adhesion and showed AF after immersion in the pH 8 and pH 12.5 solutions. Comparative Composition 2.1 lost adhesion and showed AF after immersion in all solutions. In summary, compared to Comparative Composition 1.2 (which did not contain an adhesion promoter), the addition of these commonly used adhesion promoters neither improved nor adversely affected adhesion to the membrane.

[0071] Inventive Example 1 - Curable Compositions Comprising Isocyanate-Terminated Urethane Acrylates (Isocyanate-Functionalized Adhesion Promoters) Various photocurable formulations incorporating an isocyanate-terminated urethane acrylate (i.e., an isocyanate-functionalized adhesion promoter) with an acrylate functionality of 1 and an isocyanate functionality of 2.2 (i.e., Ebecryl 4396) were formulated as shown in Table 6 below.

[0072] [Table 6]

[0073] These formulations were cured and tested for Shore hardness and adhesion to membranes. The results are shown in Table 7. Table 7 also reports the amount of Ebecryl 4396 in each formulation and the isocyanate NCO weight % for each formulation, calculated based on the NCO % in Ebecryl 4396.

[0074] [Table 7]

[0075] Film adhesion for all formulations showed substrate failure (SF) before immersion in the aqueous solutions. All polyetherurethane-containing formulations (inventive compositions 1.1, 1.2, and 1.3) maintained film adhesion (SF) in all three solutions. Thus, the addition of Ebecryl 4396 improved film adhesion after immersion in pH 12.5 solution compared to similar comparative compositions 1.1, 1.2, and 1.4, respectively. However, the addition of Ebecryl 4396 decreased Shore D hardness.

[0076] Inventive Composition 1.5 (containing polybutyl acrylate oligomer) had substrate failure (SF) after immersion at both pH 1.5 and pH 8. This is an improvement over the AF film adhesion of the similar comparative composition 1.6 (containing Ebecryl 4396). Inventive Composition 1.4 (containing polybutanediene dimethacylate oligomer) had a very similar adhesive failure mode compared to the similar comparative composition 1.5 (containing Ebecryl 4396).

[0077] Inventive Example 2 - Curable Compositions Containing Varying Amounts of Isocyanate-Terminated Urethane Acrylate (Isocyanate-Functionalized Adhesion Promoter) Various photocurable formulations were formulated using polyether urethane acrylate BR582 and adding different amounts of the isocyanate-terminated acrylate Ebecryl 4396 (i.e., an isocyanate-functionalized adhesion promoter), as shown in Table 8 below. The amount of Ebecryl 4396 ranged from 0 to 30% by weight, with the composition containing 0% Ebecryl 4396 being comparative composition 1.4.

[0078] [Table 8]

[0079] These formulations were cured and tested for Shore hardness and adhesion to membranes. The results are shown in Table 9. Table 9 also reports the amount of Ebecryl 4396 in each formulation and the isocyanate NCO weight % for each formulation, calculated based on the NCO % in Ebecryl 4396.

[0080] [Table 9]

[0081] Before immersion in the aqueous solutions, all formulations showed film adhesion to substrate failure (SF). After immersion in the three solutions for one week, all compositions (except inventive composition 2.5) showed good film adhesion (SF). After immersion in the pH 12.5 solution, inventive composition 2.5 lost adhesion (AF).

[0082] All polyetherurethane-containing formulations (inventive compositions 1.1, 1.2, and 1.3) maintained film adhesion (SF) in all three solutions. Thus, the addition of Ebecryl 4396 improved film adhesion after immersion in pH 12.5 solution compared to similar comparative compositions 1.1, 1.2, and 1.4, respectively. However, the addition of Ebecryl 4396 decreased Shore D hardness.

[0083] After immersion in both pH 1.5 and pH 8, inventive composition 1.5 (containing polybutyl acrylate oligomer) had substrate failure (SF), an improvement over the AF film adhesion of similar comparative composition 1.6 (containing no Ebecryl 4396). Inventive composition 1.4 (containing polybutanediene dimethylate oligomer) had a very similar adhesive failure mode compared to similar comparative composition 1.5 (containing no Ebecryl 4396).

[0084] Inventive Example 3 - Curable Compositions Containing Different Isocyanate-Functionalized Adhesion Promoters Various photocurable formulations using polyether urethane acrylate BR582E8 and different isocyanate-functionalized adhesion promoters were formulated as shown in Table 10 below. Comparative composition 1.4 (no adhesion promoter) was included for comparison. Ebecryl 4250 and Ebecryl 4396 are isocyanate-functionalized adhesion promoters with acrylate functionality. Ebecryl 4250 has an acrylate functionality of 3.4, an isocyanate functionality of 1.4, and an average NC content of 5%. Desmodur XP2599 and Desmodur VPLS2371 are isocyanate-functionalized adhesion promoters without acrylate functionality. Desmodur XP2599 has an average NCO% of 5%, and Desmodur VPLS2371 has an average NCO% of 3.7%.

[0085] [Table 10]

[0086] These formulations were cured and tested for Shore hardness and adhesion to membranes, and the results are shown in Table 11. Table 11 also reports the amount of isocyanate-functionalized adhesion promoter in each formulation and the isocyanate NCO weight % for each formulation, calculated based on the NCO % in the isocyanate-functionalized adhesion promoter.

[0087] [Table 11]

[0088] Prior to immersion in the aqueous solutions, adhesion to the membranes showed substrate failure (SF) for all formulations. After immersion in all three solutions for one week, all compositions (except Comparative Composition 1.4) showed substrate failure (SF) in all solutions. For compositions containing isocyanate-functionalized adhesion promoters without acrylate functionality (i.e., Desmodur XP2599 and Desmodur VPLS2371), the Shore D hardness was less than 40.

[0089] Inventive Example 4 - Curable Composition Containing Only Isocyanate-Functionalized Urethane Acrylate The isocyanate-functionalized urethane acrylate was formulated without the addition of other acrylate oligomers or monomers. Curable compositions containing Ebecryl 4396, Ebecryl 4250, and a combination of the two are shown in Table 12 below.

[0090] [Table 12]

[0091] These formulations were cured and tested for Shore hardness and adhesion to membranes, and the results are shown in Table 13. Table 13 also reports the amount of isocyanate-functionalized adhesion promoter in each formulation and the isocyanate NCO weight % for each formulation, calculated based on the NCO % in the isocyanate-functionalized adhesion promoter.

[0092] [Table 13]

[0093] Before immersion in the aqueous solutions, adhesion to the film showed substrate failure (SF) for all formulations. After immersion in all three solutions for one week, all compositions showed substrate failure (SF) in all solutions.

Claims

1. a) a (meth)acrylate-functionalized urethane component in an amount of 20% to 60% by weight based on the total weight of the curable composition; b) a (meth)acrylate monomer in an amount of 20% to 40% by weight based on the total weight of the curable composition, and c) a photoinitiator in an amount of 0.2 wt % to 5 wt %, based on the total weight of the curable composition; A photocurable composition comprising: the photocurable composition further comprises d) an isocyanate-functional adhesion promoter in an amount of 5% to 60% by weight based on the total weight of the curable composition; The photocurable composition is a photocurable composition for surface modification of a reverse osmosis membrane having a polyamide surface, and the surface modification is performed by depositing the photocurable composition on the polyamide surface of the reverse osmosis membrane and exposing it to UV light or visible light to form a cured reaction product on the polyamide surface of the reverse osmosis membrane.

2. 10. The photocurable composition of claim 1, wherein the cured reaction product has a Shore D hardness of 30 or greater.

3. The photocurable composition of claim 1, wherein the curable composition has a viscosity of 10,000 to 100,000 cps.

4. 10. The photocurable composition of claim 1, wherein the curable composition has a thixotropy index of 1.5 to 10.

5. 10. The photocurable composition of claim 1, wherein the (meth)acrylate-functionalized urethane component is a polyether urethane acrylate oligomer or a polyester urethane acrylate.

6. The photocurable composition of claim 1 , wherein the (meth)acrylate monomer is polyethylene glycol diacrylate.

7. The photocurable composition of claim 1 , wherein the (meth)acrylate monomer has a viscosity of less than 1,000 cps.

8. The photocurable composition of claim 1 wherein the isocyanate-functionalized adhesion promoter also contains (meth)acrylate functionality.

9. 10. The photocurable composition of claim 1, wherein the isocyanate-functionalized adhesion promoter is selected from the group consisting of isocyanate-terminated urethane acrylates, isocyanate-terminated aliphatic prepolymers, and combinations thereof.

10. 10. The photocurable composition of claim 1, wherein the photoinitiator is a polymeric structure having attached thereto at least one chromophore that is excited by radiation in the UV or visible light range.

11. The photocurable composition of claim 1 further comprising a filler.

12. a) a reverse osmosis membrane with a polyamide surface; and b) a cured reaction product of the photocurable composition of claim 1 disposed on at least a portion of the polyamide surface of the reverse osmosis membrane; A composite membrane structure comprising:

13. 13. The composite membrane structure of claim 12, wherein the cured reaction product is adhesively bonded to at least a portion of the polyamide surface of the reverse osmosis membrane.

14. 13. The composite membrane structure of claim 12, wherein the cured reaction product is disposed in a predetermined pattern on at least a portion of the polyamide surface of the reverse osmosis membrane.

15. 15. The composite membrane structure of claim 14, wherein the predetermined pattern is selected from the group consisting of stripes, waves, circles, ellipses, arcs, squares, rectangles, diamonds, pentagons, hexagons, stars, chevrons, random patterns, and combinations thereof.

16. 13. The composite membrane structure of claim 12, wherein the polyamide surface of the reverse osmosis membrane is constructed from polyamide and / or comprises reactive hydroxyl-functionalized moieties.

17. a) i) a (meth)acrylate-functionalized urethane component in an amount of 20% to 60% by weight based on the total weight of the curable composition; ii) a (meth)acrylate monomer in an amount of 20% to 40% by weight based on the total weight of the curable composition; and iii) a photoinitiator in an amount of 0.2 wt % to 5 wt %, based on the total weight of the curable composition; providing a curable composition comprising: The photocurable composition further comprises iv) an isocyanate-functionalized adhesion promoter in an amount of 5% to 60% by weight based on the total weight of the curable composition; b) exposing the curable composition to a UV or visible light source to form a cured reaction product; 1. A method for producing a cured reaction product comprising: The photocurable composition is a photocurable composition for surface modification of a reverse osmosis membrane having a polyamide surface, and the surface modification is performed by depositing the photocurable composition on the polyamide surface of the reverse osmosis membrane and exposing it to UV light or visible light to form a cured reaction product on the polyamide surface of the reverse osmosis membrane.

18. 18. The method of claim 17, wherein the cured reaction product has a Shore D hardness of 30 or greater.

19. 18. The method of claim 17, wherein the (meth)acrylate-functionalized urethane component is a polyether urethane acrylate oligomer or a polyester urethane acrylate oligomer.

Images