Abstract: In order to offer coatings with improved resistance to solvents which can be prepared by cationic polymerization under irradiation, the choice is made of a composition comprising at least one monomer, oligomer or polymer of general formula (I): in which: A1 is chosen from polyester blocks, polyurethane blocks, hydrocarbon-comprising backbones of mono- or polycarboxylic acid and addition products of a polycarboxylic acid and of a cycloaliphatic diepoxide, m is a number from 1 to 6, R1 is a cycloaliphatic group carrying a hydroxyl group situated in the a position with respect to the oxygen atom to which R1 is bonded, R2 is a second cycloaliphatic group carrying an oxirane group situated at the chain end, and B is chosen from one or more covalent bonds, an oxygen atom and linear, branched or cyclic hydrocarbon-comprising radicals.

Abstract: The present invention relates to novel resin compositions containing at least one solid or liquid actinic radiation-curable and cationically polymerizable organic substance, an actinic radiation-sensitive initiator for cationic polymerization, an actinic radiation-curable and radical-polymerizable organic substance and an actinic radiation-sensitive initiator for radical polymerization. The actinic radiation-curable and cationically polymerizable organic substance is at least one glycidylether of a polyhydric aliphatic, alicyclic or aromatic alcohol having at least three epoxy groups with epoxy equivalent weight between 90 and 800 grams per equivalent, at least one solid or liquid alicyclic epoxide with an epoxy equivalent weight between 90 and 330 grams per equivalent having at least two epoxy groups and monomer purity greater than about 90% by weight, or at least a solid or liquid epoxycresol novolac or epoxyphenol novolac having epoxy equivalent weight between 130 and 350, or mixtures thereof.

Abstract: In one embodiment the present invention provides a coated substrate comprising a substrate, a radiation-cured coating on at least a portion of the substrate, wherein the coating comprises an inherent macroscopic texture. In another embodiment, the present invention provides a pre-cured coating mixture comprising a radiation-curable resin and an initiator, wherein the radiation-curable resin and the initiator form a pre-cured coating mixture capable of forming a macroscopic texture upon application of the mixture on a substrate. In another embodiment the present invention provides a pre-cured coating mixture comprising a radiation-curable resin, an initiator, and texture-producing particles having an effective size to provide a macroscopic texture upon application of the mixture on a substrate.

Abstract: An interpenetrating polymer network (IPN) or semi-interpenetrating polymer network (semi-IPN) comprises a first phase which is continuous and comprises a flexible polymer and a second phase which is a fluorescent or nonfluorescent durable dispersed or continuous phase and comprises a dye and a polymer, wherein the polymer enhances durability of the dye. Such networks are particularly useful in fluorescent traffic signs or safety devices or in pavement marking tape or paint.

Abstract: Compositions, which are stable on storage, which make it possible to obtain elastomer coatings. The compositions are obtained from a hydroxylated urethane prepolymer and from a mixture of acrylate monomer and oligomers, capable of giving an elastomer by thermal or photochemical radical polymerization; the urethane prepolymer being obtained by condensation of a conjugated diene oligomer comprising hydroxylated endings, optionally mixed with a chain extender, with a polyisocyanate compound. These compositions can be used in the protection of electrical and/or electronic components and generally as coatings for metal surfaces or for plastic surfaces.

Abstract: A game ball having a cover formed from a crosslinkable thermoplastic polyurethane is disclosed. Various types of game balls are described including golf balls and softballs. By selective exposure to radiation, the thermoplastic polyurethane cover is crosslinked and its hardness is increased. Typically, increases in hardness values of at least 2 units on the Shore D scale are realized upon exposure to 3.5 Mrads of gamma radiation.

Abstract: A radiation-curable composition for optical fiber coatings comprising about 10 wt. % to about 90 wt. % of at least one radiation-curable oligomer (A), about 10 wt. % to about 90 wt. % of at least one radiation-curable monomer diluent (B), and an effective amount of at least one photoinitiator (C) represented by formula (1): wherein Ar1 to Ar3 are aromatic groups which may have one or more substitution groups.

Abstract: A photosensitive resin composition comprising an aromatic polyimide precursor, wherein a 10 &mgr;m thick layer of precursor has light transmittance at a wavelength of 365 nm of at least 1% and a 10 &mgr;m thick polyimide film made from the resin composition by imidation ring closure and deposited on a silicon substrate results in a residual stress of at most 25 MPa. The composition can be patterned through i-line exposure followed by development with alkaline solutions, and can be imidized into low-stress polyimide patterns. Electronic components having the polyimide patterns have high reliability.

Abstract: New imido(meth) acrylates of general formula (1), wherein R1, R2 and R3 may be the same or different and each represents H or CH3; R4 to R7 may be the same or different and each represents H or CmH2m+1 (in which m is 1 to 6); and n represents 1 to 4, and radiation-curable compositions prepared from them, easily cured by the irradiation with radiations, particularly ultraviolet rays, to form cured compositions excellent in weather resistance, abrasion resistance and adhesion to a base, and free from the problem of odor.

Abstract: An ultraviolet-curable adhesive for bonding optical disks, which comprises (A) a radical-polymerizable vinyl compound, (B) an &agr;-hydroxyalkylphenone compound as a photopolymerization initiator, and (C) 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1-one, and which can provide optical disk products which are small in warping of disks, retain sufficient performances even under high temperature and high humidity and have a good appearance.

Abstract: A barrier rib for an EL display element. The rib is formed from the radiation sensitive resin composition containing (A) an alkali soluble resin, (B) a polymerizable compound having an ethylenically unsaturated bond, and (C) a radiation sensitive polymerization initiator.

Abstract: The present invention relates to a composition for coating optical fibers which contains an oligomer capable of being polymerized, a monomer suitable to control the viscosity of the composition, and an adhesion promoter which includes a compound containing a cyclic structure interposed between at least two reactive silanes which are independently an alkoxysilane or a halosilane. Another composition of the present invention includes an oligomer capable of being polymerized, a monomer suitable to control the viscosity of the composition, an adhesion promoter which includes a compound containing a reactive silane group, and a carrier. The present invention also relates to optical fibers and methods of making such optical fibers using the compositions of the present invention.

Abstract: These compositions comprise at least one compound (A) and at least one compound (B) containing electron enriched or depleted olefinic double bonds, respectively.

Abstract: Crosslinkable polymers which can exhibit second order nonlinear optical properties and methods of forming and crosslinking such polymers are disclosed. The crosslinkable polymers are combined with a crosslinking agent. Optionally, the crosslinking agent can exhibit second order nonlinear optical properties. In one embodiment, the crosslinking agent is thermally reactive. Alternatively the crosslinking agent is photoreactive. The combined polymer and crosslinking agent are exposed to an electric field which is sufficient to cause a component of the polymer which can exhibit second order nonlinear optical properties to be poled. The polymer is then crosslinked by the crosslinking agent. The crosslinking agent can be a guest compound that is-covalently bound to the polymer, which operates as a host compound.

Abstract: A surfacially ultraviolet radiation-crosslinked article formed of a homogeneous composition including an elastoplastic material, a cross-linker component that is cross-linkable by free-radical polymerization, and a free-radical source material generating free radicals in exposure to ultraviolet radiation, wherein the elastoplastic material is surfacially cross-linked by exposure to ultraviolet radiation, wherein the sub-surface bulk volume of the article is non-cross-linked, and the article is resiliently deformable from and resiliently recoverable to a shape of the article when it was exposed to ultraviolet radiation for surfacial cross-linking thereof. The article is particularly amenable to embodiment as a catheter, or other similar medical device for cardiovascular or other medical procedures.

Abstract: Disclosed is a composition comprising a blend of (a) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (b) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator.

Abstract: A photo curable resin composition, which comprises (A) an acid-modified, vinyl group-containing epoxy resin, (B) an elastormer, (C) a photopolymerization initiator, (D) a diluent and (E) a curing agent, can gives a high performance cured film having distinguished heat resistance, humidity-heat resistance, adhesibility, mechanical characteristics and electrical characteristics, and a photosensitive element, which comprises a support and a layer of the photo curable resin composition laid on the support, has distinguished heat resistance, humidity-heat resistance, adhesibility, mechanical characteristics and electrical characteristics.

Abstract: An ultraviolet curable coating composition for cationic electrodeposition applicable to metal plated materials which composition comprises 100 weight parts of acrylic resin containing 10 to 70% by weight poly-functional acrylate per se having 3 or more acryloyl groups and 90 to 30% by weight of a resin of molecular weight 2,000-30,000 having a cationic electrodeposition property, and 0.1-10 weight parts of 2 or more species of photopolymerization initiators which absorb ultraviolet radiation in a wavelength range of 300-400 nm, as effective ingredients. The coating composition can readily be deposited electrically on metal materials including plated products and plastic materials provided with electrical conductivity and cured by irradiation of ultraviolet radiation within a short period of time to give a dry coating film which is appreciable in adhesiveness to the plated materials and good in appearance.

Abstract: The specification describes optical fiber coating materials and methods for making optical fiber gratings wherein the material of the optical fiber coatings comprises vinyl ether functionalized monomers, together with oligomeric or polymeric thickeners and a cationic photoinitiator. These coating materials are highly transparent to UV radiation used to write optical gratings in the optical fibers but still absorb sufficiently at other wavelengths to be cured effectively using UV radiation.

Abstract: A cutable topcoat composition and apparatus useful for preparing stable data carrying devices, such as multi-layered laminates, and methods for preparing and using the composition. The composition includes a polymerizable composition and a polymeric binder. The polymerizable composition includes hard and flexible polymerizable subunits in a ratio that optimizes flexibility while retaining good adhesion and plasticizer resistance. In a preferred embodiment, a polymerization initiator is also included in the composition. Optionally, a chain transfer agent may also be added to the composition. The composition is substantially plasticizer free. The methods of using the composition include incorporating the composition into a topcoat film useful for storing the topcoat composition prior to use in preparing data-carrying devices, such as cards.

Abstract: Radiation-curable inner and outer primary optical fiber coatings are disclosed having both fast cure speed and reduced rates of yellowing. The compositions comprise particular photoinitiators and UV absorbers which are used in amounts to provide the combination of properties. The UV absorber can have ethylenic unsaturation. Outer primary coatings can be formulated to screen inner primary coatings and have fast cure speed.

Abstract: A composition which comprises a mixture of (A) a first component comprising a polymer, at least some of the monomer repeat units of which have at least one photosensitivity-imparting group thereon, said polymer having a first degree of photosensitivity-imparting group substitution and being of the formulae specified in the claims, and (B) a second component which comprises either (1) a polymer having a second degree of photosensitivity-imparting group substitution lower than the first degree of photosensitivity-imparting group substitution, wherein said second degree of photosensitivity-imparting group substitution may be zero, wherein the mixture of the first component and the second component has a third degree of photosensitivity-imparting group substitution which is lower than the first degree of photosensitivity-imparting group substitution and higher than the second degree of photosensitivity-imparting group substitution, or (2) a reactive diluent having at least one photosensitivity-imparting group per

Abstract: A method is disclosed for preparing an electronic assembly using a reworkable underfill encapsulant in which the encapsulant is cured in situ from a curable composition comprising one or more mono-functional maleimide compounds, or one or more mono-functional vinyl compounds other than maleimide compounds, or a combination of maleimide and vinyl compounds, a curing initiator and optionally, one or more fillers or adhesion promoters.

Abstract: The present invention relates to a radiation-curable binder BM consisting of a copolymer which is composed of: A) from 80 to 99% by weight of a hydroxyl-containing polyether acrylate and/or polyester acrylate A), which optionally contains a mono-, di- and/or polyamine AA) as adduct, and of B) from 1 to 20% by weight of benzophenonetetracarboxylic acid, its anhydrides and/or its esters. The invention additionally relates to processes for the preparation of the binder BM and to the use of the binders BM in radiation-curable coating compositions.

Abstract: This invention relates to star-branched polymers containing pendent olefinic groups which have been crosslinked using actinic radiation and the use of these polymers in adhesives and coating applications.

Abstract: This invention discloses a radiation curable coating composition which is comprised of (1) a crosslinked polymeric resin which is comprised of repeat units which are derived from (a) at least one member selected from the group consisting of acrylate monomers and vinyl aromatic monomers and (b) a crosslinking monomer; (2) an acrylate diluting monomer; and (3) a photocatalyst.

Abstract: Novel substituted diaryl ketones, photopolymerization compositions including the compounds, and methods using the same are disclosed. Polymerization of compositions which include the compounds of the invention may be activated by irradiating the composition with ultraviolet light using conventional techniques and radiation sources to give greatly improved cure speeds. The compounds of the invention also show a significantly elevated level of reactivity at a narrow wavelength band, with a peak emission wavelength at or near 308 nm. Because of the increased level of activity, the photoinitiator can be used in considerably lower amounts.

Abstract: Ultraviolet radiation curing of inks on game balls, golf balls and the like is disclosed. Production inks, logo inks and methods for forming production prints and logos on golf balls, game balls and the like are disclosed. To form an ultraviolet radiation curable water-insoluble production ink, at least an adhesion promoting component is added to an ink base.

Abstract: The invention relates to crosslinked polymers, which are polymerisation products of a polymerisable mixture that comprises the following components:a) a macromer of formula C ##STR1## wherein Macro is an m-valent radical of a macromer from which the number m of groups Rx.sub.x --H has been removed,each R.sub.x, independently of the others, is a bond, --O--, --NR.sub.N -- or --S-- wherein R.sub.N is hydrogen or lower alkyl,PI* is a bivalent radical of a photoinitiator,R.sub.aa is the moiety of a photoinitiator that forms the less reactive free radical on cleavage of the photoinitiator, andm is an integer from 1 to 100,b) a copolymerisable vinyl monomer andc) a copolymerisable crosslinker.The polymers are suitable especially for the production of mouldings, such as for contact lenses.

Abstract: A negatively operating photoresist composition comprising: (a) a polyimide precursor containing repeating structural units of formula (1) ##STR1## the composition comprises in all as many structural units of formula (I), which have residues R.sub.2, that the composition can be developed by means of aqueous-alkaline developers for photoresists, which are free of organic solvents.

Abstract: An interpenetrating polymer network (IPN) or semi-interpenetrating polymer network (semi-IPN) comprises a first phase which is continuous and comprises a flexible polymer and a second phase which is a fluorescent or nonfluorescent durable dispersed or continuous phase and comprises a dye and a polymer, wherein the polymer enhances durability of the dye. Such networks are particularly useful in fluorescent traffic signs or safety devices or in pavement marking tape or paint.

Abstract: A curable topcoat composition and apparatus useful for preparing stable data carrying devices, such as multi-layered laminates, and methods for preparing and using the composition. The composition includes a polymerizable composition and a polymeric binder. The polymerizable composition includes hard and flexible polymerizable subunits in a ratio that optimizes flexibility while retaining good adhesion and plasticizer resistance. In a preferred embodiment, a polymerization initiator is also included in the composition. Optionally, a chain transfer agent may also be added to the composition. The composition is substantially plasticizer free. The methods of using the composition include incorporating the composition into a topcoat film useful for storing the topcoat composition prior to use in preparing data carrying devices, such as cards.

Abstract: A macromonomer of the formula I is described:Q--B(L--B).sub.n T (I)wherein n is zero or at least 1.0;Q is a polymerizable group;B may be the same or different and is a difunctional block of molecular weight in the range of from 100 to 8000 and wherein at least one B is a residue from a difunctional polymer or copolymer wherein B has a molecular weight of 248 to 8000 comprising silicone repeat units of formula II ##STR1## where R.sub.1 and R.sub.2 may be the same or different and are selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, aryl, haloalkyl, haloalkenyl, haloalkynyl, haloaryl, heterocyclyl and haloheterocyclyl;L is a difunctional linking group; andT is a terminal group.The macromonomer may be used preferably in the production of contact lenses.

Abstract: A visible radiation-curable solder resist composition which comprises a resin component, a component for promoting photo-polymerization or -crosslinking, and optionally a diluent and any other additives, the resion componebt comprising a novolak resin skeleton and a polyfunctional acrylic monomer and the component for promoting photo-polymerization or -crosslinking comprising a photo-reaction initiator, a sensitizing dye and a heterocyclic compound having at least two endocyclic nitrogen atoms.

Abstract: Disclosed is a composition for preparing a thermal ink jet printhead which comprises a mixture of (A) a polymer, some monomer repeat units of which have at least one photosensitivity-imparting group thereon, said polymer having a first degree of photosensitivity-imparting group substitution measured in milliequivalents photosensitivity-imparting group per gram either (1) a polymer having a second degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram lower than the first degree of photosensitivity-imparting group substitution, wherein said second degree of photosensitivity-imparting group substitution may be zero, wherein the mixture of the first component and the second component has a third degree of photosensitivity-imparting group substitution measured in milliequivalents of photosensitivity-imparting group per gram which is lower than the first degree of photosensitivity-imparting group substitution and higher than the second degr

Abstract: The liquid oligomeric compositions of this invention are made by the Michael addition reaction of acetoacetate functional donor compounds with multifunctional acrylate receptor compounds where the equivalent ratios of multifunctional acrylate to acetoacetate vary from .gtoreq.1:1 to .gtoreq.13.2:1 depending on the functionality of both multifunctional acrylate and acetoacetate. Unuseable gelled or solid oligomer products occur below the claimed ranges. The liquid oligomers of this invention are further crosslinked to make coatings, laminates and adhesives.

Abstract: Adhesive coatings designed primarily for protecting, restoring, repairing, or modifying surfaces of, objects made of polymeric materials. Such coatings are particularly useful in application over worn, cracked, discolored, or otherwise defective objects made of polyacrylic, polystyrene, and polycarbonate resins. The adhesives of this invention are basically comprised of blends containing a substantial concentration of tetrahydrofurfuryl methacrylate and/or furfuryl methacrylate.

Abstract: Disclosed are: (1) an optical resin composition comprising Component A: a thiourethane prepolymer compound prepared by reacting a polythiol compound having at least 3 functional groups and an intramolecular sulfide bond, with a polyisocyanate compound in a molar ratio of --SH to --NCO ranging from 3.0 to 7.0 Component B: at least one (meth)acrylate compound having at least 2 functional groups; and Component C: a compound radically polymerizable with Components A and B, in 10 to 50% by weight, 35 to 70% by weight, and 5 to 30% by weight, respectively; (2) a preparation process for an optical resin by photopolymerization; (3) an optical resin; and (4) a prepolymer suitable for Component A. The composition is a novel, rapidly polymerizable composition for an optical resin. Furthermore, a resin prepared by curing the composition not only has a high refractive index and a high Abbe number, but also is excellent in transparency and optical homogeneity.

Abstract: This invention relates to a liquid crystal display apparatus formed by sealing a liquid crystal between two substrates having electrodes and an alignment film with a seal material, the production process comprising the steps of attaching two substrates in a vacuum, compressing under atmospheric pressure to provide a uniform cell gap, a temporary hardening process of the seal material by ultraviolet ray irradiation and a main hardening process of the seal material by heating, wherein a radically polymerizable curing resin is used in the liquid crystal seal material. The method provides a liquid crystal display panel having a uniform cell gap, without dislocation of the alighnment between substrates, or discharge of uncured component of a seal material to the liquid crystal, capable of having a seal material firmly attached to the substrates even at panel corner portions, and having an excellent straightness and moisture resistance of the seal material.

Abstract: Disclosed is a process which comprises reacting a polymer of the general formula ##STR1## wherein x is an integer of 0 or 1, A is one of several specified groups, such as ##STR2## B is one of several specified groups, such as ##STR3## or mixtures thereof, and n is an integer representing the number of repeating monomer units, with (i) a formaldehyde source, and (ii) an unsaturated acid in the presence of an acid catalyst, thereby forming a curable polymer with unsaturated ester groups. Also disclosed is a process for preparing an ink jet printhead with the above polymer.

Abstract: A chemically amplified positive resist composition contains (A) an organic solvent, (B) a base resin in the form of a polysiloxane having phenolic hydroxyl groups some of which are protected with alkoxyalkyl groups and having a weight average molecular weight of 2,000-50,000, (C) a photoacid generator, and (D) a vinyl ether group-containing compound. The composition has high sensitivity to actinic radiation, is developable with aqueous base to form a resist pattern, and lends itself to fine patterning.

Abstract: The present invention provides ultraviolet curable or electron beam curable fluorescent inks and ink concentrates, which cure upon exposure to ultraviolet or electron beam radiation. The synthesis of the fluorescent ink and ink concentrates does not involve the use of volatile organic solvents, so removal of solvents is not necessary during the manufacturing process. The fluorescent inks and ink concentrates display minimal, consistent color shift when cured. The cured fluorescent inks and ink concentrates are solvent resistant, particularly to methyl ethyl ketone, methanol, nonane, and sec butyl alcohol. The fluorescent ink and ink concentrate is comprised of: from about 20 to 90%, preferably from about 30 to 70%, more preferably from about 30 to 60% by weight of an oligomer, which is either a formaldehyde oligomer or a cyclic-aliphatic oligomer; from about 0.

Abstract: Negative working photoresist compositions containing:a) a polyimide primer containing recurring structural units of formula (I) in the specification as well asb) a photoinitiator for polymerizing olefin double bonds, which are characterized by in that they containat least one other component c), which is selected from the group consisting ofc1) organosilicon compounds with one or more hydroxyl groups,c2) compounds of formula (IIa) in the specification,c3) compounds of formula (IIb) as in the specification,c4) mixtures comprised of two or more components selected from components of c1), c2) and c3),have the advantage that they can be developed with a developer, which comprises up to 50 to 100 wt. % of an aqueous-alkaline medium, whereby the balance to 100 wt. % is formed by one or more organic solvents.

Abstract: A near infrared rays-curing putty composition containing (A) a polymerizable ethylenically unsaturated group-containing resin, (B) a polymerizable ethylenically unsaturated compound and (C) a near infrared rays polymerization initiator, said near infrared rays polymerization initiator (C) being a near infrared rays-absorbing cationic dye and a resin powder consisting of gelation polymer fine particles.

Abstract: A composition that is useful in the preparation of radiation curable coatings is provided. The composition comprises the reaction product of an epoxy component comprised of a diepoxide and an acid component comprised of an ethylenically unsaturated carboxylic acid or reactive derivative thereof, reacted in the presence of a polyamide based on a polymerized fatty acid. The polyamide preferably has a number average molecular weight of less than about 10,000 g/mole. Also provided is a polymerizable composition comprised of the reaction product and a reactive diluent. A method of coating a substrate is also provided which comprises applying to a substrate a composition comprised of the reaction product and exposing said composition to radiation to cure said composition.

Abstract: An ultraviolet-curing liquid undercoating composition for use in metallizing FRP, which is a one-component type, has an unlimited pot life, and is excellent in adhesion and heat resistance. The composition comprises 20 to 80 parts by weight of a compound(s) containing at least two (meth)acryloyl groups in its molecule, 80 to 20 parts by weight of oil-modified alkyd resin(s), and 2 to 15 parts by weight of a sensitizer, optionally further 5 to 20 parts by weight of an amino resin based on 100 parts by weight in total of the above compound and the above alkyd resin(s). It is suited for the undercoating of an automotive reflector.

Abstract: This photopolymerizable composition includes an grafted reactive telomer containing trifluoroethyl methacrylate units, a reactive diluent and a photopolymerization initiator. It gives hydrophobic transparent coatings.

Abstract: Radiation-sensitive organo-halogen compounds that have a photo-labile halomethyl-1,3,5-triazine moiety and a polymeric moiety within the same molecule. The compounds of this invention are comprised of a polymeric moiety having attached or incorporated within its structure at least one 1,3,5-triazine nucleus, said triazine nucleus having at least one halomethyl substituent attached to a carbon atom of the triazine nucleus. These compounds are capable of being stimulated by actinic radiation at wavelengths of from about 250 to about 900 nanometers to generate free radicals and/or acids. The compounds of this invention are useful as photoinitiators in free radical polymerization reactions, oxidation-reduction reactions, or reactions sensitive to acid, and they also exhibit the capability to crosslink upon exposure to light.

Abstract: Thermoplastic compositions are used for the fabrication of provisional (i.e., temporary) prosthetic devices, especially for the fabrication of crowns and bridges, and as liners for crowns. Preferably, the thermoplastic compositions comprise free-radically polymerizable functionality so that the material can be polymerized after being shaped to a desired configuration.

Abstract: A coating agent for producing scratch-resistant coatings on plastic articles, which comprises:(1) 1-30 wt. % of a prepolymer, as a thickener (IP thickener), which prepolymer is bound in the composition of the coating by polymerization;(2) 20-80 wt. % of multifunctional acrylates, multifunctional methacrylates or mixtures thereof;(3) 5-75 wt. % of a thinner;(4) 0.01-10 wt. % of a UV-initiator;(5) 0-20 wt. % of customary additives; wherein the prepolymer (1) is obtained by radical polymerization of:(a) 90-99 wt. % of C.sub.1 -C.sub.8 -alkyl esters of acrylic- or methacrylic acid; and(b) 1-10 wt. % of a sulfur-containing regulator having at least three thiol groups. The coating system is distinguished by high scratch-resistance and good weatherability.