Abstract: The invention includes embodiments that relate to a method of improving the abrasion resistance of a plastic article. The method comprises: (a) providing a composition comprising at least one siloxane compound and at least one thermoplastic polymeric material; (b) forming an article from the composition of step (a); and (c) exposing the article formed in step (b) to an energy source selected from an electron beam source, a gamma radiation source, and a combination thereof. The invention also includes embodiments that relate to an article comprising an abrasion resistant surface.

Abstract: The present invention provides an ink composition having excellent ink ejection stability and stretching property, curable with a high sensitivity by irradiation of radiation rays, and capable of forming an image excellent in rubfastness and blocking resistance, an inkjet recording method using the ink composition, and a printed article. The ink composition includes (a) a polymer having a siloxane structure and a polymerizable group on a side chain thereof, (b) a polymerizable compound, and (c) a photopolymerization initiator, and the inkjet recording method includes a step of ejecting the ink composition onto a recording medium to be recorded with an inkjet recording apparatus and a step of curing the ink composition by irradiating active radiation rays on the ejected ink composition.

Abstract: The invention relates to novel crosslinkable copolymers which are obtainable by (a) copolymerizing at least one hydrophilic monomer having one ethylenically unsaturated double bond and at least one crosslinker comprising two or more ethylenically unsaturated double bonds in the presence of a chain transfer agent having a functional group; and (b) reacting one or more functional groups of the resulting copolymer with an organic compound having an ethylenically unsaturated group. The crosslinkable copolymers of the invention are especially useful for the manufacture of biomedical mouldings, for example ophthalmic mouldings such as in particular contact lenses.

Abstract: Novel blends of photo-initiators and photo-absorbers are disclosed. By the proper selection of the type and amount of absorber and initiator used in a composition, it is possible to regulate the conditions under which photo-induced reactions occur. In a specific embodiment, blends of UV initiators and photoabsorbers are used to control the conditions under which UV initiated polymerization occurs.

Abstract: The present invention is to provides an ultraviolet-curable resin composition which contains a composite resin (A) having a polysiloxane segment (a1) having a silanol group and/or a hydrolytic silyl group as well as a polymerizable double bond and a polymer segment (a2) other than the polysiloxane segment (a1), and a photo initiator (B). The ultraviolet-curable resin composition is able to form a cured coating film excellent in weatherability such as scratch resistance, acid resistance, alkali resistance and solvent resistance, without heating.

Abstract: The present invention relates to curable silicone compositions which include a fluorescent agent for detection purposes and which have a cure system which enables the silicone compositions to possess improved depth of cure. The silicone compositions are photocurable, and may also be moisture or heat curable.

Abstract: The present invention provides a multi-layered object having a hard coat layer capable of improving anti-staining property, anti-staining durability, scratch resistance, abrasion resistance and the like. A multi-layered object comprising a hard coat layer and a light transmitting layer, wherein the hard coat layer is formed from a composition for hard coat comprising: an active energy ray-curable silicone-acrylic copolymer (A); and an active energy ray-curable polyfunctional compound (B), and wherein the active energy ray-curable silicone-acrylic copolymer (A) contains: a polysiloxane block (a-1), an acrylic block (a-2) containing an active energy ray-curable double bond group and a fluoroalkyl group-containing acrylic block (a-3).

Abstract: Coating compositions yielding cured coatings that exhibit excellent abrasion-resistance and hardness for use on polymeric substrates such as the front side of optical lenses, in a manner that meets or exceeds the stringent requirements for such use. The compositions include the hydrolysis product of an epoxy functional alkoxy silane, a viscosity-reducing amount up to 50% by weight, solids basis, of a monomeric (silanol free) epoxy functional epoxy silane, and colloidal silica present in an amount sufficient to improve abrasion resistance as compared to a composition lacking the colloidal silica.

Abstract: An active energy ray curable coating composition comprising a mixture (A) of compounds each having a (meth)acryloyl group and a colloidal silica (B), wherein the mixture (A) contains from 22 to 62% of a copolymer (A1) having (meth)acryloyl groups and obtained by reacting a specific amount of a radical polymerizable monomer (a1) having a quaternary ammonium salt group, a radical polymerizable monomer (a2) having a hydroxyl group and a radical polymerizable monomer (a3) having a lactone ring-opening addition structure. A molded product having a coating film made of a cured product of the coating composition. To form a coating film made of a cured product which provides excellent abrasion resistance, transparency and antistatic property and undergoes little decrease in the antistatic property even when kept at a high humidity.

Abstract: A photocurable composition for a pressure-sensitive adhesive layer includes a pressure-sensitive adhesive binder, a reactive acrylate having a silicone backbone, a thermal curing agent, and a photoinitiator. The pressure-sensitive adhesive binder includes a copolymer of acrylic monomers, and a low molecular weight acrylate bonded to the copolymer, the low molecular weight acrylate having at least one pendent carbon-carbon double bond.

Abstract: Disclosed are environmentally friendly, substantially all solids coating compositions which are curable using ultraviolet and visible radiation. In certain embodiments, the disclosed coating compositions are suitable for coating flexible objects and/or objects having angular features, such as, but not limited to, flexible metal objects with angular features. In other embodiments, the cured coatings have improved slip properties and at least 6 H hardness. Such embodiments can served as substitutes for “hard chrome” coatings, TEFLON® coatings, coatings comprising TEFLON®, or TEFLON® like coatings. In addition, methods are disclosed for coating surfaces, or at least a portion of the surfaces, and curing of the coated surface to obtain partially or fully cured coated surfaces. Furthermore, articles of manufacture incorporating fully cured coated surfaces are disclosed, including, for example leaf springs, hydraulic rods and cylinders.

Abstract: Polymerizable materials which contain (1) 1 to 80 wt.-% of at least one polysiloxane, (2) 0.1 to 5 wt.-% of one or more initiators for radical polymerization, (3) 0 to 60 wt.-% of radically polymerizable monomer and (4) 1 to 50 wt.-% of one or more radically polymerizable monomers which carry at least phosphonic acid group, sulphonic acid group and/or mono- or dihydrogen phosphoric acid ester group, the polysiloxane (1), the monomer (3) or both being substituted by fluorine. The materials are suitable in particular for the coating of natural or artificial teeth.

Abstract: The present invention relates to dental materials comprising liquid, nanoparticulate functionalized hydrophobic co-condensates of tetraalkyl silicates with functionalized trialkoxysilanes of the formula I P—(CH2)n—Si(OR)3 where P, R and n independently of one another have the following meanings: P=a polymerizable CH2?CH—, CH2?CH—O—, styryl, (meth)acrylic or (meth)acrylamide group or an SH group capable of polyaddition, R=methyl, ethyl or propyl and n=from 3 to 15, which can be prepared by co-condensation of tetraalkyl silicates with alkyltrialkoxysilanes functionalized in the ? position and subsequent end group functionalization with trimethylsilyl groups; The invention further relates to the use of the dental materials for filling composites, fixing cements or materials for coatings.

Abstract: The invention relates to core-shell structured silicone rubber graft polymers that comprise a core a) from a silicium-organic polymer that corresponds to the general formula (R2SiO2/2)x.(RSiO3/2)y.(SiO4/2)z, wherein x=0 to 99.5 mole %, y=0.5 to 100 mole %, z=0 to 50 mole %, wherein R is the same or different and represents alkyl or alkenyl groups having 1 to 6 C atoms, aryl groups or substituted hydrocarbon groups and at last one shell c) from an organic polymer. The silicone rubber graft copolymers are obtained by producing the organic shell c) by radical polymerization at a temperature of not more than 65° C. and adding the initiator in at least two portions to the reaction vessel, with a further addition at least 2 minutes after start of the polymerization.

Abstract: Disclosed is an anti-UV reflector for distributing a light from a point light source or a linear light uniformly over a target. The anti-UV reflector mainly includes a light reflecting polymeric substrate and a protecting layer of anti-UV material provided on the polycarbonate substrate for reducing yellowing in the polycarbonate substrate. When a light from a point light source or a linear light illuminates the anti-UV reflector, UV radiation in the light is filtered or absorbed by the protecting layer thereby reducing yellowing in the polyearbonate substrate.

Abstract: The present invention relates to compositions which include compounds that are end-capped with silanes containing radiation cure groups. In addition, the invention relates to a method for preparing such compounds. In particular, the radiation cure groups are attached to the silane via a methylene linkage.

Abstract: Disclosed are environmentally friendly, substantially all solids coating compositions which are curable using ultra violet and visible radiation. In addition, methods for coating surfaces, or at least a portion of the surfaces, and curing of the coated surface to obtain partially or fully cured coated surfaces are also disclosed. Furthermore, articles of manufacture incorporating fully cured coated surfaces are disclosed, in particular motor vehicles and motor vehicle parts or accessories.

Abstract: A multi-photon reactive composition comprises an ethylenically unsaturated liquid polysilazane precursor, a multi-functional thiol additive, a multi-ethylenically-unsaturated additive different from the polysilazane, and a multi-photon photocuring composition. The invention can be used to provide ceramic-based microstructures as, for example, high temperature resistant materials, including devices such as microcombustors, micro-heat-exchangers, sensor and actuator systems, microfluidic devices, and micro-optics systems that can be used independently or integrated into other systems.

Abstract: A method for treating the surface of a fluorinated biomedical device is provided comprising the steps of (a) plasma treating the fluorinated biomedical device with a hydrogen-containing atmosphere to reduce the fluorine or C—F bonding content of the fluorinated biomedical device; and (b) subjecting the hydrogen plasma treated surface to a plasma-polymerization reaction in a hydrocarbon-containing atmosphere to form a polymeric carbonaceous layer on the surface of the biomedical device.

Abstract: The present invention provides inks and methods for making colored silicone hydrogel contact lenses. The ink of the invention comprises an actinically-curable binder copolymer comprising fluorine-containing segments and is characterized by having capability to be cured actinically or thermally to form a colored film on a molding surface of a mold or a silicone hydrogel contact lens and by having an increased durability in a solvated state in a silicone-hydrogel lens formulation in relation to a control colored film obtained from a control ink including an actinically-curable fluorine-free binder copolymer. The invention also provides methods for making colored silicone hydrogel contact lenses based on print-on-mold processes for producing colored contact lenses.

Abstract: An additive (and methods for a coating composition that includes at least one an agent for improving the performance of the coating composition, selected from a Michael addition product of siloxane further containing one or more active hydrogen containing functional moieties with two or more acrylate groups; a high molecular weight adduct having multiple alkoxysilane moieties; a compound including at least one terminal unsaturation and multiple alkoxysilyl groups; an organometallic compound that includes an element selected from silicon, titanium, zirconium, aluminum, or any combination thereof.

Abstract: The present invention has for its object to provide a curable composition which, despite its low viscosity, gives a cured product with a high gel fraction, low residual tack, low modulus, high elongation, and good flexibility. The present invention relates to a curable composition comprising the following two components: (A) a vinyl polymer having at least one crosslinking silyl group on the average per molecule: and (B) a photocurable substance, (C) an air oxidation-curable substance, (D) a high molecular plasticizer, (E) a reactive plasticizer or (F) a compound having one silanol group in its molecule and/or a compound capable of reacting with moisture to give a compound having one silanol group in the molecule.

Abstract: This invention relates to a silicone resin composition which exhibits high heat resistance, high transparency and high dimensional stability and thus can be suitably used for optical applications such as a lens, an optical disc, an optical fiber, a substrate for a plat panel display, a window material for an automobile, and the like.

Abstract: A method for generating spontaneously aligned surface wrinkles utilizes control of local moduli-mismatch and osmotic pressure. The method includes modifying the surface of an elastomeric layer to form a superlayer that is stiffer and/or less absorbent than the elastomeric layer. The elastomeric layer is then swollen with a polymerizable monomer, which causes buckling of the superlayer. The monomer is then polymerized, dimensionally stabilizing the surface buckling. The budded surfaces generated by the method are useful in a wide variety of end-use applications, including microlenses, microlens arrays, compound microlenses, diffraction gratings, photonic crystals, smart adhesives, mechanical strain sensors, microfluidic devices, and cell culture surfaces.

Abstract: The present invention relates to photoradiation and/or moisture curing silicone compositions and methods for producing and using the same. In particular, the methods of the present invention permit controlled growth of a polymer, and allow for incorporation of pendant functional groups along the length of the polymer.

Abstract: The invention provides a photopolymerizable composition comprising: flame-retardant particles which contains a hydrated metal and have an average diameter of about 1 to 500 nm; and a photopolymerization reactive material. The hydrated metal preferably includes at least one selected from the group consisting of a hydrated magnesium, hydrated calcium, hydrated aluminum, hydrated zinc, hydrated barium, hydrated copper and hydrated nickel. A cover layer which comprises an organic compound or a polysilicone is preferably formed on surfaces of the flame-retardant particles. The invention provides a flame-retardant resin-formed article which is formed of the photopolymerized photopolymerizable composition. A flame retardancy of the article measured in accordance with the UL-94 test preferably scores HB or higher.

Abstract: An elastomer blend is made by admixing fluoroelastomer and fluorinated silicone polymer (with optional filler and/or conductive particulate) into a polymeric admixture in weight ratios to provide a low vaporous hydrocarbon permeation rate and high thermal strain value in thermally robust elastomer cured from the blend. The blend is of especial use for making gaskets for use in high stress conditions at elevated operating temperatures.

Abstract: The invention relates to a durably homogeneous, low-viscosity, radiation-curable coating material comprising a) x (meth)acrylated polysiloxanes and if desired b) y (meth)acrylated organic compounds and c) at least one particulate emulsifier having an average particle size of <1000 nm in at least one dimension, with the proviso that x?1, y?0, the sum of x+y?2 and the mixture of components a) and b) alone is not durably homogeneous.

Abstract: A non-volatile lubricious coating composition is provided for use with medical devices, such as hypodermic needles, catheters, and the like. The coating composition includes a first siloxane polymer having a very low viscosity less than about 50 centistokes, a second siloxane polymer having a high viscosity greater than about 1,000 centistokes, a reactive silicone polymer which is capable of crosslinking upon exposure to radiation, such as a UV curable silicone acrylate, and a photoinitiator to accelerate cross-linking of the reactive silicone polymer. The coating composition may further include an aminofunctional siloxane polymer to promote adhesion to metal surfaces when used with needles. The coating composition provides flowability without the need for any volatile organic solvent, and is capable of curing to provide adhesion and lubricity.

Abstract: An active energy ray (e.g. UV rays)-curable organopolysiloxane resin composition comprises (A) 100 parts by weight of an organopolysiloxane resin containing epoxy groups and aromatic hydrocarbon groups, (B) 0.05 to 20 parts by weight of a photo acid generator, (C) 0.01 to 20 parts by weight of a photosensitizer or photo-radical generator, and (D) 0 to 5,000 parts by weight of an organic solvent. An optical transmission component made of the above-mentioned composition cured by irradiation with active energy rays (for example, UV rays). A method for manufacturing an optical transmission component by irradiating the above-mentioned composition with active energy rays (for example, UV rays).

Abstract: A thermosetting resin composition which forms a cured coating is provided. This resin composition is capable of providing the supporting substrate with scratch resistance, crack resistance, smudge proof property, removability of oil-base felted markers by wiping, and antistatic property. Also provided is an article having a coating formed from such composition.

Abstract: A process for producing intraocular lenses (IOLs) capable of absorbing blue light and ultraviolet light using photo curing. Intraocular lenses so produced block blue light and ultraviolet light from reaching the retina of an eye implanted with the IOL. By blocking blue light and ultraviolet light from reaching the retina, the IOL thereby prevents potential damage to the retina.

Abstract: The invention provides a process for producing siloxane-containing release coatings which comprises curing a siloxane-containing coating material by irradiation with microwaves.

Abstract: The present invention provides for the use of radiation-curable coating compositions comprising at least one radiation-curable organopolysiloxane having (meth)acrylic ester groups and a photoinitiator, wherein said photoinitiator includes at least one compound of the general formula in which R1 is a linear or branched alkyl radical having 3 to 18 carbon atoms, preferably 4 to 12 carbon atoms, R2 is an alkyl radical having 1 to 4 carbon atoms, preferably hydrogen, R3, R4 are alkyl radicals having 1 to 6 carbon atoms, which may also have been linked to form a 5- or 6-membered carbon ring or one of these radicals may also be hydrogen, and R5 is an alkyl or alkanoyl radical, preferably hydrogen; for preparing adhesive coating materials and producing adhesive coatings.

Abstract: The invention concerns dental compositions. Said composition comprises (1) a silicone crosslinkable and/or polymerizable by cation process; (2) an efficient amount of at least an initiator such as onium borate; (3) at least a photosensitizer ; and (4) a dental filler present in the composition in a proportion of at least 10 wt. % relative to the composition total weight. Said dental compositions are useful for making dental prostheses or for dental restoration.

Abstract: A block of intermediate transfer material for use in a printing apparatus having an intermediate transfer member, said intermediate transfer member being equipped with a heater to heat said intermediate transfer member to a temperature of at least about 40° C., said intermediate transfer member having a surface with a first shape, a marking material applicator situated to apply marking material in an imagewise pattern to the intermediate transfer member, and a transferring apparatus to transfer the imagewise pattern of marking material to a final recording substrate, said block of intermediate transfer material comprising a silicone polymer containing monomers of the formula wherein R1, R2, R3, R4, R5, x, y, and z are as defined herein, wherein the monomers can be directly bonded to each other or bonded through spacer groups, said block of intermediate transfer material having a surface with a second shape substantially the complement of the first shape.

Abstract: Disclosed are environmentally friendly, substantially all solids coating compositions which are curable using ultraviolet and visible radiation. In addition, the disclosed coating compositions are suitable for coating flexible objects and/or objects having angular features, such as, but not limited to, flexible metal objects with angular features. In addition, methods are disclosed for coating surfaces, or at least a portion of the surfaces, and curing of the coated surface to obtain partially or fully cured coated surfaces. Furthermore, articles of manufacture incorporating fully cured coated surfaces are disclosed, including, for example leaf springs. Also disclosed are methods, processes, production lines, articles of manufacture, and factories which incorporate these environmentally friendly, substantially all solids coating compositions curable using ultraviolet and visible radiation.

Abstract: Disclosed are environmentally friendly, substantially all solids coating compositions which are curable using ultraviolet and visible radiation. In addition, the disclosed coating compositions are suitable for coating thermally sensitive objects and/or rusted surfaces. In addition, methods are disclosed for coating surfaces, or at least a portion of the surfaces, and curing of the coated surface to obtain partially or fully cured coated surfaces are also disclosed. Furthermore, articles of manufacture incorporating fully cured coated surfaces are disclosed, including, for example gas tanks such as, barbeque propane tanks. Also disclosed are methods, processes, production lines, articles of manufacture, and factories which incorporate these environmentally friendly, substantially all solids coating compositions curable using ultraviolet and visible radiation.

Abstract: Disclosed are environmentally friendly, substantially all solids coating compositions which are curable using ultra violet and visible radiation. In addition, methods for coating surfaces, or at least a portion of the surfaces, and curing of the coated surface to obtain partially or fully cured coated surfaces are also disclosed. Furthermore, articles of manufacture incorporating fully cured coated surfaces are disclosed, in particular motor vehicles and motor vehicle parts or accessories.

Abstract: A coating composition that can be cured by actinic or ionizing radiation is disclosed. The coating composition is made up of at least one polysiloxane compound one polysiloxane compound having the following structure (I) or (II): wherein: m has a value of at least 2; m? ranges from 0 to 75; n ranges from 0 to 75; n? ranges from 0 to 75; each R, which may be identical or different, is selected from H, OH, a monovalent hydrocarbon group, a monovalent siloxane group, and mixtures of any of the foregoing; and —Ra comprises the following structure (III): —R3—X ??(III) wherein —R3 is selected from an alkylene group, an oxyalkylene group, an alkylene aryl group, an alkenylene group, an oxyalkenylene group, and an alkenylene aryl group; and X represents a group comprising at least 2 carbamyl alkyl(meth)acrylate groups or 2 carbamyl alkyl epoxy groups.

Abstract: A novel organosiloxane polymer is obtained by addition reaction of an organohydrogenpolysiloxane, an alkenyl-containing organopolysiloxane and an unsaturated compound of formula (3) or (4). Using the organosiloxane polymer, a photo-curable resin composition is prepared which can be exposed to radiation having a wide range of wavelength and developed to form a pattern.

Abstract: A gas phase species (such as ozone, H2O2, or N2O) is photodissociated with ultraviolet light into a reactive species that is patternwise directed (e.g., through a mask) onto a surface of a material, such as an organosilicate. The reactive species reacts with the material to form a polar oxidation product such as —OH, thereby resulting in discrete hydrophilic regions separated from each other by hydrophobic regions. The degree of hydrophilicity of the discrete regions may be tailored by controlling the concentration of the reactive species, the ultraviolet light intensity, the temperature to which the material is heated, and exposure time. End products made with the methods are suitable for use in a biomolecular array.

Abstract: The invention concerns a radiation-curable silicone coating based on silicones having a viscosity not more than 1500 mPa's, radiation-curable, comprising: (a) at least a liquid polyorganopolysiloxane polymer Pa with viscosity higher than 500 mPa's and having at least a terminal unit of formula [Z—Si (R1)(R2)—O—] (I), and (b) at least a polyorganopolysiloxane Pb, with viscosity less than 150 mPa's and having at least a unit of formula (I) defined above and/or at least a unit of type D of formula —[—(Si(R1)(Z)—O—]— (ii), Z being a crosslinkable and/or polymerizable group; (c) at least an efficient amount of at least an initiator consisting of onium borate.

Abstract: A radiation-curable ink jet ink free of unreactive volatile organic compounds and comprising an alkyl (meth)acrylate in which the alkyl group has at least 8 carbon atoms, a poly(alkylene oxide) modified poly(dimethyl siloxane), further radiation curable material, and a pigment can be printed on nonporous substrates, particularly plastic substrates such as vinyl substrates, with good dot gain and appearance.

Abstract: A dual-cure silicone composition is provided that is useful to make an encapsulating/potting compound. The dual-cure silicone exhibits both UV- and moisture-initiated curing mechanisms, with the UV-initiated curing mechanism providing very rapid curing compared to conventional dual-cure silicones. The dual-cure silicone is an elastomeric material on curing. In a preferred embodiment, the dual-cure silicone composition is made from a mixture of a first polysiloxane component having terminal mercapto and alkoxy functionality, and a second polysiloxane component having terminal vinyl and alkoxy functionality. Methods of making the first and second polysiloxane components also are disclosed.

Abstract: To provide a radiation-sensitive curable liquid resin composition having excellent applicability and capable of producing a film excelling in hardness, scratch resistance, adhesion, transparency, and appearance of the surface of the film. A curable liquid resin composition comprising: (A) particles prepared by bonding at least one oxide of an element selected from the group consisting of silicon, aluminum, zirconium, titanium, zinc, germanium, indium, tin, antimony, and cerium to a specific organic compound which comprises a polymerizable unsaturated group and a group shown by —X—C(?Y)—NH— (wherein X is NH, O, or S, and Y is O or S), and preferably a silanol group, (B) a compound having two or more polymerizable unsaturated groups in the molecule, (C) a specific alkylene glycol organic solvent, and preferably (D) a polymerization initiator.

Abstract: The present invention has for its object to provide a curable composition which, despite its low viscosity, gives a cured product with a high gel fraction, low residual tack, low modulus, high elongation, and good flexibility. The present invention relates to a curable composition comprising the following two components: (A) a vinyl polymer having at least one crosslinking silyl group on the average per molecule: and (B) a photocurable substance, (C) an air oxidation-curable substance, (D) a high molecular plasticizer, (E) a reactive plasticizer or (F) a compound having one silanol group in its molecule and/or a compound capable of reacting with moisture to give a compound having one silanol group in the molecule.

Abstract: A composition including nanoparticles each having an acidic polymerizable siloxane moiety. For example, a hydrolysis stable, self-etching, self-priming dental adhesive composition including 90 to 10 percent by weight of an aqueous phase, and 10 to 90 percent by weight of acidic polymerizable nanoparticles. The acidic polymerizable nanoparticles are obtainable by hydrolysis of a mixture containing one or more hydrolyzable organosilicon compounds wherein (i) at least a portion of the hydrolyzable organosilicon compounds contains one or more polymerizable groups and (ii) at least a portion of the hydrolyzable organosilicon compounds contain one or more acidic moieties.

Abstract: The invention concerns a radiation-curable silicone coating, comprising (a) at least a liquid polyorganosiloxane having a viscosity of about 10 to 10000 mPa's at 25° C. and bearing a crosslinkable/polymerisable function Fa on at least a M and/or T unit, and/or at least a crosslinkable/polymerisable function on at least a D unit; (b) at least a liquid linear polyorganosiloxane B having a viscosity of about 10 to 10000 mPa's at 25° C. and bearing two crosslinkable/polymerisable functions Fb on at least a M unit; (c) a cationic photoinitiator of onium borate type.

Abstract: The invention provides hydrogels for use in the production of biomedical devices. In particular, the invention provides hydrogels formed from siloxane prepolymers and a hydrophilic monomer, which hydrogels are optically transparent.