Photocurable (meth)acrylate composition

Abstract

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

Description

Background Art 1. Technical Field

[0002] The present invention relates to curable (meth)acrylate compositions comprising isocyanate functional compounds and methods for preparing and using such compositions. More specifically, the present invention relates to photocurable (meth)acrylate compositions for forming features on membrane surfaces, especially membranes for osmosis and reverse osmosis applications, such as membrane filters.

[0003] 2. Brief description of related technology

[0004] Curable compositions have been widely used in sealing, adhesive, coating and potting applications, to name a few. The type of backbone and the choice of curable groups are generally selected with reference to the specific end-use application and the environment in which it is intended to be used. Polymers with varying degrees of unsaturation as well as other functional crosslinking groups have been used.

[0005] For bonding and spacing of reverse osmosis (RO) membranes, commonly used adhesives (i.e., curable compositions) are two-part room temperature curing polyurethanes or epoxies. The two parts must be mixed and applied before the gel time to form the parts, which is undesirable for some applications. Photocurable acrylates containing (meth)acrylate terminated polybutadiene have been disclosed for membrane wrinkle protection, but bonding to membranes has not been reported. Polybutadiene acrylate oligomers generally have adhesion to many substrates. Polyether urethane acrylate resins containing photocurable acrylates are known to have good hydrolytic stability, but bonding to RO membranes in alkaline solutions is challenging.

[0006] Adhesion promoter plays a role at the interface between organic binding material and organic / inorganic substrate to strengthen the bonding between two materials. These two materials are usually different in the following manner to make it difficult to form a strong adhesive bond between them: for example, the difference in compatibility, chemical reactivity, surface characteristics and thermal expansion coefficient. The effect of adhesion promoter is to bond these different materials into a strong adhesive bond structure in a chemical and physical manner. Adhesion promoter can give tolerance to environment and other destructive forces (such as heat and moisture), and the destructive force usually acts on the bonding site to destroy the bond strength.

[0007] Adhesion promoters are generally molecules with reactive functional groups at both ends of the molecule. Functional groups known to increase the adhesion of polymers to surfaces include phosphoric and carboxylic acids (metal adhesion) and silyl ethers (glass / silicon adhesion), which hydrolyze to produce reactive Si-OH bonds. Monomers with functional groups such as acids, amines, and hydroxyls can impart adhesion to polymers to many substrates. Various adhesion promoters have been used to improve adhesion to substrates such as glass, plastics, and metals, but the use of adhesion promoters for adhesion to filter membranes is not clear. Dual-cure compositions with isocyanate and acrylate end groups have been used in hot melt coatings and conformal coatings, but have not yet been used to enhance adhesion to membranes.

[0008] Moreover, even if sufficient adhesion is initially obtained between the curable composition and the membrane surface, the materials adhered to the membrane surface, such as spacer features, need to maintain good adhesion to the membrane after curing and during the use and maintenance of the membrane. For example, the use and maintenance of RO membranes require that the membrane surface and the features / spacers attached thereto are exposed to an aqueous environment. In particular, the cleaning of the membrane generally requires that the membrane be exposed to acidic and alkaline aqueous solutions. The features formed by the curing composition may face degradation when in contact with water (particularly in acidic and alkaline solutions), resulting in loss of quality, mechanical strength, and adhesion to the membrane during use and maintenance.

[0009] There is a need for photocurable (meth)acrylate compositions and methods of using such compositions to form features on film surfaces that allow for good adhesion of the cured composition to the film surface, as well as maintaining the good adhesion, quality, and mechanical strength of the cured composition during subsequent use and maintenance of the film. Summary of the invention

[0010] The present invention provides a photocurable composition, the composition comprising: a) a (meth)acrylate functional polyurethane component; b) a (meth)acrylate monomer; and c) a photoinitiator, wherein the (meth)acrylate functional polyurethane component comprises an isocyanate functional group and / or the photocurable composition further comprises: d) an isocyanate functional adhesion promoter, and wherein when deposited on a polyamide surface of a substrate and exposed to ultraviolet light or visible light, the curable composition forms a cured reaction product on the polyamide surface of the substrate, and the cured reaction product exhibits adhesion to the polyamide surface of the substrate, wherein the substrate is characterized by: 1) the substrate fails after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about 1 week; and / or 2) the substrate fails after immersion in alkaline aqueous (pH=12.5) conditions at a temperature of about 50°C for about 1 week; and / or 3) the substrate fails after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50°C for about 1 week, wherein the substrate is a reverse osmosis membrane having a polyamide surface.

[0011] In other aspects of the present invention, a composite film structure is provided, comprising: a) a film comprising at least one surface; and b) a cured reaction product of the above-described curable composition disposed on at least a portion of at least one surface of the film.

[0012] In a further aspect of the present invention, a method for producing a cured reaction product is provided, the method comprising the steps of: a) providing a curable composition, the curable composition comprising i) a (meth)acrylate functional polyurethane component; ii) a (meth)acrylate monomer; and iii) a photoinitiator; wherein the (meth)acrylate functional polyurethane component comprises an isocyanate functional group and / or the photocurable composition further comprises: iv) an isocyanate functional adhesion promoter; and b) exposing the curable composition to an ultraviolet or visible light source to form a cured reaction product, wherein when deposited on a polyamide surface of a substrate and exposed to The curable composition forms a cured reaction product on a polyamide surface of a substrate when exposed to ultraviolet light or visible light, and the cured reaction product exhibits adhesion to the polyamide surface of the substrate, wherein the substrate is characterized by: 1) failure of the substrate after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about 1 week; and / or 2) failure of the substrate after immersion in alkaline aqueous (pH=12.5) conditions at a temperature of about 50°C for about 1 week; and / or 3) failure of the substrate after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50°C for about 1 week, wherein the substrate is a reverse osmosis membrane having a polyamide surface. Specific implementation plan

[0013] The present invention relates to a photocurable (meth)acrylate composition comprising: a) a (meth)acrylate functional polyurethane component; b) a (meth)acrylate monomer; and c) a photoinitiator, wherein the (meth)acrylate functional polyurethane component comprises an isocyanate functional group and / or the photocurable composition further comprises: d) an isocyanate functional adhesion promoter, and wherein when deposited on a polyamide surface of a substrate and exposed to ultraviolet light or visible light, the curable composition forms a cured reaction product on the polyamide surface of the substrate. The cured reaction product exhibits adhesion to a polyamide surface of a substrate characterized in that: 1) the substrate fails after immersion in acidic aqueous (pH=1.5) conditions at a temperature of about 50°C for about 1 week; and / or 2) the substrate fails after immersion in alkaline aqueous (pH=12.5) conditions at a temperature of about 50°C for about 1 week; and / or 3) the substrate fails after immersion in neutral aqueous (pH=7.0) conditions at a temperature of about 50°C for about 1 week, wherein the substrate is a reverse osmosis membrane having a polyamide surface.

[0014] In one aspect of the present invention, the curable composition has a viscosity (at 25° C., 10 s -1 Down).

[0015] In one aspect of the invention, the curable composition has an optimized rheology that is effectively balanced to allow sufficient thixotropy for easy deposition, but to maintain its physical structure after deposition and prior to curing. As used herein, "thixotropy" refers to a substance that becomes less viscous when pressure is applied (e.g., mixing or shaking) and becomes more viscous in the absence of such pressure (e.g., under static conditions).

[0016] In a further aspect of the present invention, the curable composition has a thixotropic index of about 1.5 to about 10 or about 2 to about 8. As used herein, "thixotropic index" refers to the curable composition having a thixotropic index of about 1.5 to about 10 or about 2 to about 8. -1 The viscosity (in cps) at the speed is related to the curable composition in 10s -1 The ratio of viscosity (in cps) at the speed (1s -1 Viscosity / 10s -1 The viscosity can be determined using known methods, such as a cone and plate rheometer, a parallel plate rheometer, or a rotational viscometer such as a Brookfield viscometer.

[0017] In one aspect of the invention, the (meth)acrylate functionalized polyether polyurethane component is a polyether polyurethane acrylate oligomer. In one aspect of the invention, the (meth)acrylate functionalized polyether polyurethane component can be synthesized by reacting a diisocyanate with a polyether polyol to produce an isocyanate terminated polyurethane. The isocyanate terminated polyurethane is then reacted with a hydroxy terminated acrylate to provide an acrylate group at the end of the oligomer. If the terminal isocyanate is not completely reacted with the hydroxy acrylate, the isocyanate will remain in the structure as a reactive group in addition to the acrylate terminal group.

[0018] Suitable urethane acrylate oligomers include, but are not limited to, aliphatic urethane acrylates. Examples of suitable urethane acrylate oligomers include 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), BR 582E8, BR-930D, BR-3042, BR 3471 (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 one aspect of the invention, the polyurethane acrylate oligomer is Ebecryl 880-20R (Allnex), Ebecryl 8807 (Allnex), BR 582E8 (Dymax), or combinations thereof.

[0019] In a further aspect of the present invention, the (meth)acrylate functional polyether polyurethane component is present in an amount of about 20 wt % to about 60 wt % or about 30 wt % to about 50 wt %, based on the total weight of the curable composition.

[0020] In another aspect of the invention, the (meth)acrylate functional polyether polyurethane component further comprises isocyanate functional groups. Suitable (meth)acrylate functional polyether polyurethane components comprising isocyanate functional groups include, but are not limited to, Ebecryl 4141, 4250, 4396, 4397, 4510 and 4765 (all from Allnex), and combinations thereof.

[0021] 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, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-methoxybutyl (meth)acrylate, 2-Perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate, diperfluoromethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate. In one aspect of the invention, the (meth)acrylate monomer is a 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 (ideally triethylene glycol di(meth)acrylate), hydroxypropyl (meth)acrylate, bisphenol A di(meth)acrylates (such as ethoxylated bisphenol A (meth)acrylate ("EBIPA" or "EBIPMA")), as well as tetrahydrofuran (meth)acrylate and di(meth)acrylate, citronellyl acrylate and methacrylate, hexanediol (meth)acrylate diester ("HDDA" or "HDDMA"), trimethylolpropane triester (meth)acrylate, tetrahydrodicyclopentadienyl (meth)acrylate, ethoxylated trimethylolpropane triacrylate ("ETTA"), triethylene glycol diacrylate, and triethylene glycol dimethacrylate ("TRIEGMA").

[0022] In one aspect of the present invention, the (meth)acrylate monomer is present in an amount of about 10 wt % to about 50 wt % or about 20 wt % to about 40 wt %, based on the total weight of the curable composition.

[0023] In a further aspect of the present invention, the (meth)acrylate monomer has a viscosity of less than about 1,000 cps or less than about 500 cps.

[0024] In one aspect of the invention, the isocyanate functionalized adhesion promoter is an isocyanate-terminated polyurethane acrylate, an isocyanate-terminated aliphatic prepolymer, or a combination thereof. Suitable isocyanate-terminated polyurethane acrylates include, but are not limited to, Ebecryl 4141, 4250, 4396, 4397, 4510, and 4765 (all from Allnex), and a combination thereof. Suitable isocyanate-terminated aliphatic prepolymers include, but are not limited to, Desmodur XP 2599 (Covestro), Desmodur VPLS 2371 (Covestro), or a combination thereof.

[0025] In one aspect of the present invention, the isocyanate functional adhesion promoter is present in an amount of about 5 wt % to about 60 wt % or about 10 wt % to about 30 wt %, based on the total weight of the curable composition.

[0026] In some aspects of the invention, the curable composition is a photocurable or photocurable composition, i.e., curing using light such as visible light or ultraviolet light (UV). In some aspects of the invention, the curable composition can be cured using a light source, such as a bulb or LED that produces visible light or ultraviolet light.

[0027] In additional aspects of the invention, the photoinitiator can be a UV light initiator, a visible light initiator or a combination of UV and visible light initiators.In one aspect of the invention, the photoinitiator is a polymer structure having attached thereto at least one chromophore excited by radiation in the UV or visible range.

[0028] A variety of UV photoinitiators can be used. UV photoinitiators are generally effective in the 200 to 400 nm range, particularly in the portion of the spectrum close to invisible light and the visible portion just beyond this, for example >200 nm to about 390 nm.

[0029] Initiators that will respond to ultraviolet radiation to initiate and induce cure of the (meth)acryloyl-functional curable components 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, 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.

[0030] Examples of such ultraviolet photoinitiators include those commercially available from IGM Resins under the trade names "OMNIRAD" (formerly "IRGACURE") and "DAROCUR", specifically "OMNIRAD" 184 (1-hydroxycyclohexyl phenyl ketone), 907 (2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one), 369 (2-benzyl-2-N,N-dimethylamino-1-(4-morpholinophenyl)-1-butanone), 500 (a combination of 1-hydroxycyclohexyl phenyl ketone and benzophenone), 651 (2,2-dimethoxy-2-phenylacetophenone), 1700 (bis(2,6-dimethoxybenzoyl)-2-phenylacetophenone), and 1710 (bis(2,6-dimethoxybenzoyl)-2-phenylacetophenone).

[00136] The invention relates to a method for curing photoinitiators comprising: curing the photoinitiators by using a UV light curing agent, a UV curing agent comprising: ...

[0031] Initiators suitable for use in the present invention that will respond to visible light to initiate and induce cure include camphorquinone peroxyester initiators, 9-fluorene carboxylic acid peroxyesters, visible light [blue] photoinitiators, d1-camphorquinone, "IRGACURE" 784DC (a substituted dipentyl titanium based photoinitiator), and combinations thereof.

[0032] 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., which is incorporated herein by reference, discloses a photopolymerization initiator comprising a combination of a 3-keto-substituted coumarin compound and an active halogen compound. Many exemplary compounds are disclosed. Such photopolymerization initiators are cured by exposure to light having a wavelength range between about 180 nm and 600 nm. U.S. Pat. No. 4,258,123 to Nagashima et al., which is incorporated herein by reference, discloses a photosensitive resin composition comprising an initiator component that generates free radicals when irradiated with actinic light. Such components include various triazine compounds, as more fully described therein.

[0033] Other useful components are disclosed in the following documents, which are incorporated herein by reference. European Patent Publication No. EP 0369 645 A1 discloses a three-part photoinitiator system comprising a trihalomethyl-substituted s-triazine, a sensitizing compound capable of absorbing radiation in the range of about 300-1000 nm, and an electron donor. Exemplary sensitizing 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; para-substituted aminostyryl ketone compounds; aminotriarylmethanes; merocyanines; squarylium dyes; and pyridine dyes. Exemplary donors are also disclosed, including: amines; amides; ethers; ureas; ferrocene; sulfinic acid and its salts; salts of ferrocyanide; ascorbic acid and its salts; dithiocarbamic acid and its salts; xanthates; ethylenediaminetetraacetic acid salts; and salts of tetraphenylboric acid. This initiator is sensitive to both ultraviolet and visible light.

[0034] Other useful components are disclosed in the following documents incorporated herein by reference. European Patent Publication No. EP 0563 925 A1 discloses a photopolymerization initiator, the initiator including a sensitizing compound capable of absorbing radiation in the range of about 250-1000nm and 2-aryl-4,6-bis(trichloromethyl)-1,3,5-triazine. Exemplary disclosed sensitizing compounds 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, pyridine dyes, (thio)pyran dyes, porphyrin dyes, triarylmethane dyes, (poly)methane dyes, aminostyryl compounds and aromatic polycyclic hydrocarbons. These photopolymerization initiators are sensitive to ultraviolet and visible light.

[0035] U.S. Pat. No. 5,395,862 to Neckers et al., which is incorporated herein by reference, discloses a fluorone photoinitiator that is sensitive to visible light. Such a fluorone initiator system also includes a co-initiator that can accept electrons from the excited fluorone substance. Exemplary co-initiators are disclosed, including: onium salts, nitrohalomethanes, and diazonium sulfones. U.S. Pat. No. 5,451,343 to Neckers et al., which is incorporated herein by reference, discloses fluorone and pyronin-Y derivatives as initiators that absorb light of wavelengths greater than 350 nm. U.S. Pat. No. 5,545,676 to Palazzotto et al., which is incorporated herein by reference, discloses a three-part photoinitiator system that cures under ultraviolet or visible light. The three-part system includes an aryl iodonium salt, a sensitizing compound, and an electron donor. Exemplary iodonium salts include diphenyl iodonium salts. Exemplary sensitizers and electron donors for the three-part system are also disclosed. Additionally, the sensitizer is capable of absorbing light in the range of about 300 to about 1000 nm.

[0036] In a further aspect of the present invention, the photoinitiator is present in an amount of about 0.2 wt % to about 5 wt % or about 1 wt % to about 3 wt %, based on the total weight of the curable composition.

[0037] In additional aspects of the present invention, the curable composition may also include fillers. Suitable fillers include organic and inorganic fillers. Inorganic materials include silicon dioxide, silicates, aluminum oxide, asbestos, barium sulfate, calcium carbonate, calcium fluoride, carbon black, clay, diatomaceous earth, feldspar, ferromagnets, fly ash, glass fiber, gypsum, jute fiber, kaolin, lignocellulose, magnesium hydroxide, mica, microcrystalline cellulose, metal powder, quartz, starch, talc, titanium dioxide, wood flour, wood fiber and combinations thereof. Organic fillers include thermoplastic polymers such as polyvinyl acetate, polyolefins, and nylon fibers.

[0038] In one aspect of the present invention, the filler is present in an amount of about 2 wt % to about 40 wt % or about 5 wt % to about 30 wt %, based on the total weight of the curable composition.

[0039] Optional additives such as, but not limited to, co-initiators, stabilizers, rheology modifiers, defoamers, inhibitors, oxygen scavengers, dyes, pigments, 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.

[0040] The composite film structure according to the present invention comprises: a) a film comprising at least one surface; and b) a cured reaction product of the above-described curable composition disposed on at least a portion of the at least one surface of the film.

[0041] The method for preparing the cured reaction product according to the present invention comprises the following steps: a) providing a curable composition, the curable composition comprising: i) a (meth)acrylate functional polyurethane component; ii) a (meth)acrylate monomer; and iii) a photoinitiator; wherein the (meth)acrylate functional polyurethane component comprises an isocyanate functional group and / or the photocurable composition further comprises: iv) an isocyanate functional adhesion promoter, and b) exposing the curable composition to an ultraviolet or visible light source to form a cured reaction product, wherein when deposited on a polyamide surface of a substrate and exposed to the ultraviolet or visible light, the cured reaction product When exposed to light, the curable composition forms a cured reaction product on the polyamide surface of the substrate, and the cured reaction product exhibits adhesion to the polyamide surface of the substrate, wherein the substrate is characterized in that: 1) the substrate fails after immersion in acidic aqueous conditions (pH=1.5) at a temperature of about 50°C for about 1 week; and / or 2) the substrate fails after immersion in alkaline aqueous conditions (pH=12.5) at a temperature of about 50°C for about 1 week; and / or 3) the substrate fails after immersion in neutral aqueous conditions (pH=7.0) at a temperature of about 50°C for about 1 week, wherein the substrate is a reverse osmosis membrane having a polyamide surface.

[0042] In one aspect 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.

[0043] In other aspects of the composite membrane structure of the present invention, the cured reaction product is adhesively bonded to at least a portion of at least one surface of the membrane.

[0044] In other aspects of the composite film structure of the present invention, the cured reaction product is disposed on at least a portion of at least one surface of the film in a predetermined pattern. In an embodiment of the composite film structure of the present invention, the predetermined pattern is selected from stripes, waves, circles, ellipses, arcs, squares, rectangles, diamonds, pentagons, hexagons, stars, herringbones, random patterns, and combinations thereof.

[0045] In one aspect of the present invention, pattern is formed on the membrane surface by known methods, such as curable composition is printed or deposited on the membrane surface, and curable composition is cured subsequently.The pattern formed on the membrane surface by the method of the present invention is usually composed of many features formed by the cured reaction product.Usually, these features have the physical properties that make them suitable for providing intervals between the covering layers of membrane.For example, these features can provide enough spacings between the layers of spiral reverse osmosis filter membrane, to use the film with these features to optimize the operation, cleaning and life-span of reverse osmosis membrane element.In one aspect of the present invention, the pattern of feature can have the size and shape that is enough to keep enough membrane spacings and expose enough membrane surfaces to ensure the effective operation of membrane.

[0046] In general, the bond strength of an adhesive (e.g., a cured composition) to a substrate can be described by determining whether the adhesive or the substrate fails when an increasing force is applied to the adhesive to separate it from the substrate. If the adhesive maintains its integrity and the substrate is mechanically destroyed, this will be considered a substrate failure (SF). In the case where the substrate remains intact and the adhesive is mechanically destroyed, this will be considered an adhesive failure (AF).

[0047] As used herein, "substrate failure" means that when the curable composition of the present invention is cured on the polyamide surface of a reverse osmosis membrane as a substrate and the adhesion to the substrate (or membrane) is tested as described below, the substrate fails when a force is applied, as opposed to an adhesive. In other aspects 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 FILMTEC TM Flat Sheet BW30LE.

[0048] For curable compositions of the present invention, adhesion to substrate (or film) includes 1) curable compositions are cured to form beads of a cured product that adheres to the film surface, and these beads are forcibly removed from the film surface. If the film is torn, it is considered to be a substrate failure (SF). If the film remains intact, it is considered to be an adhesive failure (AF). A detailed description of the embodiments of the test method is provided in the embodiments.

[0049] The surface on which the curable composition is deposited may include the surface of any film suitable for the application of the curable composition. In one aspect of the invention, the surface on which the curable composition is deposited is a membrane surface. As used herein, "membrane" refers to a selective barrier that allows some substances to pass but prevents other substances from passing. In one aspect of the invention, the membrane is a filter membrane, that is, 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 features consisting of the curable composition can be deposited on the active surface of the membrane, or on the inactive surface of the membrane, or both.

[0050] Furthermore, hydrophilic materials, such as glycerol, can be added to the membrane to keep the membrane pores open. In addition, antifouling agents, such as polyethylene glycol, can be used in the membrane.

[0051] The isocyanate functional groups of the photocurable (meth)acrylate composition of the present invention will combine with the polyamide and / or reactive hydroxyl functional moieties on the film to form polyurethane chemical bonds. These bonds are stronger than the mechanical locking or hydrogen bonding of compositions lacking isocyanate functional groups.

[0052] In one aspect of the invention, the membrane surface is comprised of polyamide and / or includes reactive hydroxyl functional moieties.

[0053] In some aspects of the invention, the composite membrane structure according to the present invention exhibits substrate failure after being immersed in aqueous conditions for a long period of time at an elevated temperature. As used herein, "a long period of time" refers to 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, "elevated temperature" refers to 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.

[0054] In some aspects of the present invention, aqueous conditions can include acidic aqueous conditions, alkaline aqueous conditions and neutral aqueous conditions. As used herein, "acidic aqueous conditions" refers to aqueous conditions where the pH is 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, "alkaline aqueous conditions" refers to aqueous conditions where the pH is about 11 or greater, about 11.5 or greater, about 12 or greater, about 12.5 or greater, or about 13 or greater. As used herein, "neutral aqueous conditions" refers to aqueous conditions where the pH is between about 6 and about 8 or where the pH is about 7.

[0055] Example

[0056] Material

[0057] The following ingredients were used in the following examples:

[0058] Table 1

[0059]

[0060]

[0061] Test Method

[0062] The following test methods were used in the examples described below.

[0063] Viscosity and Thixotropic Index

[0064] A cone-plate rheometer (Anton Paar) was used to -1 and 10s -1 The viscosity is measured at a shear rate of 1 s. -1 and 10s -1 The viscosity ratio below.

[0065] Adhesion to membrane

[0066] The curable composition is applied to the RO membrane (FILMTEC TMFlat Sheet BW30LE) to form beads with a diameter of about 20 mil and a height of about 20 mil. The intensity used was 1.5 W / cm 2 The beads on the film were immediately cured for 10 seconds using a 405 nm LED light.

[0067] The film with the deposited beads of the solidified reaction product was immersed in aqueous solutions with different pH for different times at a temperature of 50°C. A solution of pH 1.5 was prepared by mixing 25 g of a 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 g of sodium hydroxide to 1000 g of distilled water.

[0068] The adhesion of the cured reaction product to the film was checked before and after immersion by manually removing the beads from the film using a spatula. If the film tore, it was considered a substrate failure (SF). If the film remained intact, it was considered an adhesive failure (AF).

[0069] Shore D Hardness

[0070] Shore D hardness was measured according to ASTM D2240. The material to be tested was placed between two PE films and covered with two glass plates to form a 1 mm thick sheet, and then a hardness tester with an intensity of 1.5 W / cm 2 The cured sheet was then cut into 4 pieces and then stacked for measurement by Shore hardness tester.

[0071] Comparative Example 1 - Curable Composition without Isocyanate Functional Adhesion Promoter

[0072] As shown in Table 2 below, various photocurable formulations were formulated without the addition of isocyanate resins or isocyanate functional adhesion promoters.

[0073] Table 2

[0074]

[0075] These formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 3 below.

[0076] Table 3

[0077]

[0078] Prior to immersion in aqueous solutions, all formulations showed substrate failure (SF) in adhesion to the film. After 1 week of immersion, comparative compositions 1.1-1.4 maintained SF adhesion in pH 1.5 and pH 8 solutions. Comparative composition 1.5 lost adhesion and showed AF in all 3 solutions. After immersion in pH 12.5 solution, all compositions lost adhesion and showed AF.

[0079] Comparative Example 2 - Curable Composition with Conventional Adhesion Promoter

[0080] As shown in Table 4 below, various photocurable formulations with commonly used adhesion promoters were prepared. The polyurethane acrylate oligomer Ebecryl 8807 used in Comparative Composition 1.2 was used in all compositions of this example. Commonly used adhesion promoters are: Photomer 4967, Dynasylane DAMO T, KBM 5103, Kayamer PM 2, NNDMA and HPA. For comparison purposes, Comparative Composition 1.2 (without adhesion promoter) is included.

[0081] Table 4

[0082]

[0083] These formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 5 below.

[0084] Table 5

[0085]

[0086] Before immersion in aqueous solution, the adhesion of all formulations to the film showed substrate failure (SF). After immersion in pH 12.5 solution for 1 week, all compositions lost adhesion and showed AF. After immersion in pH 1.5 and pH 8 solutions, comparative compositions 2.2, 2.3 and 2.4 maintained SF. However, comparative composition 2.5 lost adhesion and showed AF after immersion in pH 8 and pH 12.5 solutions. Comparative composition 2.1 lost adhesion and showed AF after immersion in all solutions. In summary, the addition of these commonly used adhesion promoters did not improve the adhesion of the film or adversely affect the adhesion of the film compared to comparative composition 1.2 (which did not contain any adhesion promoter).

[0087] Inventive Example 1 - Curable Compositions Containing Isocyanate-Terminated Polyurethane Acrylates (Isocyanate-Functional Adhesion Promoters)

[0088] Various photocurable formulations with the addition of an isocyanate terminated polyurethane acrylate having an acrylate functionality of 1 and an isocyanate functionality of 2.2 (ie, an isocyanate functional adhesion promoter) (ie, Ebecryl 4396) were formulated as shown in Table 6 below.

[0089] Table 6

[0090]

[0091] The formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 7 below. Also reported in Table 7 is the weight percent of isocyanate NCO in each formulation calculated based on the amount of Ebecryl 4396 in each formulation and the NCO % in Ebecryl 4396.

[0092] Table 7

[0093]

[0094] Before immersion in aqueous solution, all formulations showed substrate failure (SF) in terms of adhesion to the film. The polyether polyurethane containing formulations (inventive compositions 1.1, 1.2 and 1.3) maintained film adhesion (SF) in all 3 solutions. Thus, the addition of Ebecryl 4396 improved film adhesion after immersion in pH 12.5 solution as compared to similar comparative compositions 1.1, 1.2 and 1.3, respectively. However, the Shore D hardness decreased with the addition of Ebecryl 4396.

[0095] The inventive composition 1.5 (containing polybutyl acrylate oligomer) failed the substrate (SF) after immersion at pH 1.5 and pH 8. This is an improvement over the AF film adhesion of the similar comparative composition 1.5 (without Ebecryl 4396). The inventive composition 1.4 (containing polybutadiene dimethacrylate oligomer) had a very similar adhesion failure mode compared to the similar comparative composition 1.4 (without Ebecryl 4396).

[0096] Inventive Example 2 - Curable Compositions Containing Different Amounts of Isocyanate-Terminated Polyurethane Acrylates (Isocyanate-Functional Adhesion Promoters)

[0097] Various photocurable formulations containing polyether urethane acrylate BR582 and adding different amounts of isocyanate-terminated urethane acrylate Ebecryl 4396 (i.e., isocyanate functional adhesion promoter) were formulated as shown in Table 8 below. The amount of Ebecryl 4396 varied from 0-30 wt %, with the composition containing 0% Ebecryl 4396 being comparative composition 1.3.

[0098] Table 8

[0099]

[0100] The formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 9 below. Also reported in Table 9 is the weight percent of isocyanate NCO in each formulation calculated based on the amount of Ebecryl 4396 in each formulation and the NCO % in Ebecryl 4396.

[0101] Table 9

[0102]

[0103] Before immersion in aqueous solutions, all formulations showed substrate failure (SF) in adhesion to the film. After one week of immersion in the three solutions, all compositions (except for inventive composition 2.5) showed good film adhesion (SF). Inventive composition 2.5 showed adhesion loss (AF) after immersion in pH 12.5 solution.

[0104] The polyether polyurethane containing formulations (inventive compositions 1.1, 1.2 and 1.3) maintained film adhesion (SF) in all 3 solutions. Thus, the addition of Ebecryl 4396 improved film adhesion after immersion in a pH 12.5 solution compared to similar comparative compositions 1.1, 1.2 and 1.3, respectively. However, the Shore D hardness decreased with the addition of Ebecryl 4396.

[0105] Inventive composition 1.5 (containing polybutyl acrylate oligomer) exhibited substrate failure (SF) after immersion at pH 1.5 and pH 8. This is an improvement over the AF film adhesion of the similar comparative composition 1.5 (without Ebecryl 4396). Inventive composition 1.4 (containing polybutadiene dimethacrylate oligomer) had a very similar adhesion failure mode compared to the similar comparative composition 1.4 (without Ebecryl 4396).

[0106] Inventive Example 3 - Curable Compositions Containing Different Isocyanate Functional Adhesion Promoters

[0107] As shown in Table 10 below, various photocurable formulations containing polyether polyurethane acrylate BR582 E8 and different isocyanate functional adhesion promoters were formulated. For comparison purposes, comparative composition 1.3 (without adhesion promoter) was included. Ebecryl 4250 and Ebecryl 4396 are isocyanate functional adhesion promoters containing acrylate functional groups. Ebecryl 4250 has an acrylate functionality of 3.4, an isocyanate functionality of 1.4, and an average NC content of 5%. Desmodur XP 2599 and Desmodur VPLS2371 are isocyanate functional adhesion promoters without acrylate functional groups. Desmodur XP 2599 has an average NCO% of 5%, and Desmodur VPLS2371 has an average NCO% of 3.7%.

[0108] Table 10

[0109]

[0110] These formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 11 below. Also reported in Table 11 is the isocyanate NCO weight % in each formulation calculated based on the amount of isocyanate functional adhesion promoter in each formulation and the NCO % of the isocyanate functional adhesion promoter.

[0111] Table 11

[0112]

[0113] Before immersion in aqueous solutions, all formulations showed substrate failure (SF) in adhesion to the film. After 1 week of immersion in all 3 solutions, all compositions (except comparative composition 1.3) showed substrate failure (SF) for all solutions. For the compositions including isocyanate functional adhesion promoters without acrylate functionality (i.e. Desmodur XP 2599 and Desmodur VPLS 2371), the Shore D hardness was below 40.

[0114] Inventive Example 4 - Curable Composition Containing Only Isocyanate-Functional Polyurethane Acrylate

[0115] Isocyanate functional polyurethane acrylates were formulated without adding other acrylate oligomers or monomers. Table 12 below shows curable compositions containing Ebecryl 4396, Ebecryl 4250, and a combination of the two.

[0116] Table 12

[0117]

[0118] These formulations were cured and tested for Shore hardness and adhesion to film. The results are shown in Table 13 below. Also reported in Table 13 is the isocyanate NCO weight % in each formulation calculated based on the amount of isocyanate functional adhesion promoter in each formulation and the NCO % of the isocyanate functional adhesion promoter.

[0119] Table 13

[0120]

[0121] Prior to immersion in aqueous solutions, all formulations exhibited substrate failure (SF) in adhesion to the film. After 1 week of immersion in all 3 solutions, all compositions exhibited substrate failure (SF) for all solutions.

Claims

1. A photocurable composition, comprising, based on the total weight of the photocurable composition: a) (meth)acrylate functionalized polyether polyurethane component; b) (Meth)acrylate monomers; c) photoinitiator; as well as d) 5 to 20 wt % of an isocyanate functional adhesion promoter selected from the group consisting of isocyanate terminated polyurethane acrylates, isocyanate terminated aliphatic prepolymers, and combinations thereof, wherein when deposited on a polyamide surface of a substrate and exposed to ultraviolet light or visible light, the photocurable composition forms a cured reaction product on the polyamide surface of the substrate, and the cured reaction product exhibits adhesion to the polyamide surface of the substrate, characterized in that: 1) Substrate failure after immersion in acidic aqueous conditions with a pH of 1.5 at a temperature of 50°C for 1 week; and / or 2) Substrate failure after immersion in alkaline aqueous conditions with a pH of 12.5 at a temperature of 50°C for 1 week; and / or 3) The substrate failed after immersion in neutral aqueous conditions with a pH of 7.0 at a temperature of 50°C for one week. The substrate is a reverse osmosis membrane having a polyamide surface.

2. The photocurable composition of claim 1 wherein said cured reaction product further exhibits adhesion to said polyamide surface of said substrate characterized in that the substrate fails prior to immersion in aqueous conditions. 3 . The photocurable composition according to claim 1 , wherein the cured reaction product has a Shore D hardness of 30 or more. 4 . The photocurable composition according to claim 1 , wherein the photocurable composition has a viscosity of 10,000 to 100,000 cps. 5 . The photocurable composition according to claim 1 , wherein the photocurable composition has a thixotropic index of 1.5 to 10.

6. The photocurable composition of claim 1, wherein the (meth)acrylate functional polyether polyurethane component is present in an amount of 20 to 60 wt%, based on the total weight of the photocurable composition.

7. The photocurable composition of claim 1, wherein the (meth)acrylate functional polyether urethane component is a polyether urethane acrylate oligomer. 8 . The photocurable composition of claim 1 , wherein the (meth)acrylate monomer is present in an amount of 20 to 40 wt % based on the total weight of the photocurable composition.

9. The photocurable composition according to claim 1, wherein the (meth)acrylate monomer is polyethylene glycol diacrylate.

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

11. The photocurable composition of claim 1, wherein the photoinitiator is present in an amount of 0.2 wt% to 5 wt% based on the total weight of the photocurable composition.

12. The photocurable composition of claim 1, wherein the photoinitiator is a polymer structure having attached thereto at least one chromophore excited by radiation in the ultraviolet or visible range.

13. The photocurable composition according to claim 1, further comprising a filler.

14. A composite membrane structure, comprising: a) a membrane comprising at least one surface; and b) a cured reaction product of the photocurable composition of claim 1 disposed on at least a portion of the at least one surface of the film.

15. The composite membrane structure of claim 14, wherein the cured reaction product is adhesively bonded to at least a portion of the at least one surface of the membrane.

16. The composite membrane structure of claim 14, wherein the cured reaction product is arranged in a predetermined pattern on at least a portion of the at least one surface of the membrane. The composite film structure of claim 16 , wherein the predetermined pattern is selected from a random pattern.

18. The composite film structure of claim 17, wherein the predetermined pattern is selected from stripes, waves, circles, ovals, arcs, squares, rectangles, diamonds, pentagons, hexagons, stars, herringbone shapes, and combinations thereof.

19. The composite membrane structure of claim 14, wherein at least one surface of the membrane is comprised of polyamide and / or comprises reactive hydroxyl functional moieties.

20. A method of producing a cured reaction product, the method comprising the steps of: a) providing a curable composition, based on the total weight of the curable composition, the curable composition comprising: i) (meth)acrylate functionalized polyether polyurethane component; ii) (meth)acrylate monomers; iii) a photoinitiator; and iv) 5 to 20 weight percent of an isocyanate functional adhesion promoter selected from the group consisting of isocyanate terminated polyurethane acrylates, isocyanate terminated aliphatic prepolymers, and combinations thereof; and b) exposing the curable composition to an ultraviolet light or visible light source to form a cured reaction product, wherein when deposited on a polyamide surface of a substrate and exposed to ultraviolet light or visible light, the curable composition forms a cured reaction product on the polyamide surface of the substrate, and the cured reaction product exhibits adhesion to the polyamide surface of the substrate, characterized in that: 1) Substrate failure after immersion in acidic aqueous conditions at pH 1.5 at a temperature of 50°C for 1 week; and / or 2) Substrate failure after immersion in alkaline aqueous conditions at a pH of 12.5 at a temperature of 50°C for 1 week; and / or 3) The substrate failed after immersion in neutral aqueous conditions with a pH of 7.0 at a temperature of 50°C for one week. The substrate is a reverse osmosis membrane having a polyamide surface.

21. The method of claim 20 wherein the cured reaction product further exhibits adhesion to the polyamide surface of the substrate characterized by substrate failure prior to immersion in aqueous conditions.

22. The method of claim 20, wherein the cured reaction product has a Shore D hardness of 30 or greater.

23. The method of claim 20, wherein the (meth)acrylate functional polyether polyurethane component is present in an amount of 20 to 60 weight percent based on the total weight of the curable composition.

24. The method of claim 20, wherein the (meth)acrylate functionalized polyether urethane component is a polyether urethane acrylate oligomer.

25. The method of claim 20, wherein the (meth)acrylate monomer is present in an amount of 10 to 50 wt% based on the total weight of the curable composition.

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