Abstract: The present invention contemplates a stereolithographic apparatus and method having a liquid organic phase and a fluid phase separated by a membrane that inhibits contact between the phases.

Abstract: A method of curing a three-dimensional specimen of preformed cross-linked polymeric material containing polymerizable ethylenically-unsaturated material is provided in which the specimen is immersed in water having dissolved therein an amount of a water-soluble organic free-radical polymerization catalyst effective to transfer a polymerization-initiating amount of the catalyst into the preformed cross-linked polymeric material. This specimen containing the water-soluble organic free-radical polymerization catalyst is heated to a temperature causing polymerization, and is maintained at that temperature while the cure is completed. The aqueous bath preferably contains a catalyst mixture which includes a catalyst of oxidizing character in admixture with a reducing agent, such as an amine, and is maintained at a polymerization temperature of from 60.degree. C. to 100.degree. C. so that immersion of the specimen in a single bath completes the cure.

Abstract: An improved stereolithographic process is provided in which the formation of a thin walled three-dimensional object in a reservoir of liquid ultraviolet-curable ethylenically unsaturated material using a support is positioned immediately beneath the upper surface of the liquid reservoir with that upper surface being exposed to ultraviolet light in a pattern to solidify the liquid at and near the upper surface in a series of cross-sections of the desired three-dimensional object, one atop the other. In this way there is formed a series of superposed layers which adhere to one another to build the desired three-dimensional object within the liquid reservoir. The improvement comprises, stopping the exposure at any portion of the surface in the formation of said layers and then repeating the exposure at least once again in the production of each surface layer so that the strength and solvent resistance of the formed object are increased and its distortion is minimized.

Abstract: A stereolithographic method which employs an ultraviolet-curable liquid composition adapted to cure rapidly to a lightly cross-linked solvent-swellable three-dimensional complexly-shaped polymeric thin-walled element constituted by heat-softenable solid polymer upon exposure to ultraviolet dosage in the range of about 0.1 to about 10 Joules per square centimeter and which possesses reduced distortion comprises, from 20 to 80 weight percent, of a resinous polyacrylate or polymethacrylate dissolved in a combination of 10 to 45 weight percent of a liquid polyacrylate or polymethacrylate, which is preferably trifunctional, and 10 to 45 weight percent of liquid N-vinyl monomer, preferably N-vinyl pyrrolidone. Thus, the weight ratio of polyacrylate: polymethacrylate: N-vinyl monomer is about 1:2:2 to about 8:1:1. One of the foregoing polyacrylates or polymethacrylates is a polyacrylate and the other is a polymethacrylate so that good cure speed is accompanied by good distortion resistance.

Abstract: Radiation-curable coating compositions particularly adapted for the single coat coating of optical fibers are disclosed. These comprise (1) from 65% to 85% of a diethylenic-terminated polyurethane, which may contain urea groups, the polyurethane being based on a diisocyanate having an average molecular weight of from 400 to 5000; and (2) from 5% to 25% of an ether of a C.sub.2 -C.sub.4 alkylene glycol monoester of a monoethylenically unsaturated monocarboxylic acid, the ether being selected from the group consisting of ethoxyethyl, dicyclopentenyl, phenyl, and mixtures thereof. Ethoxyethoxyethyl acrylate is particularly preferred. A triacrylate ester, such as trimethylol propane triacrylate, is also desirably present.

Abstract: A method of investment casting utilizes a pattern produced by stereolithography in which a three-dimensional specimen is provided by light cure of ethylenically unsaturated liquid material. The stereolithography composition is constituted by the ethylenically unsaturated liquid material in admixture with an inert low thermoplastic material which weakens the pattern when heated within the mold used in the investment casting process to prevent the thermal expansion of the pattern from cracking the mold.

Abstract: An essentially isocyanate-free polyurethane, polyurea, polyethylenic oligomer is disclosed which is unusually strong and elastic and which possesses improved solvent solubility. This oligomer is the reaction product of: (1) organic diisocyanate; (2) a stoichiometric deficiency of difunctional materials reactive therewith and consisting essentially of: (A) diol component selected from polycarbonate diol and polyoxyalkylene glycol, this diol component having a molecular weight of from 200 to 2000; (B) dihydric bisphenol-based alkylene oxide adduct containing from 2-6 alkylene groups per molecule; and (C) a diprimary diamine component selected from alkylene diamine and polyoxyalkylene diamine, this diamine component having a molecular weight of from about 60 to 800. Components (A) and (B) are present in a mole ratio of, from 1:1.5 to 1:5 and component (C) is present to supply from 5 to 30 equivalent percent of the total equivalents of component (2).

Abstract: The reaction product of an adduct of an ethylenically unsaturated monohydric alcohol, such as 2-hydroxyethyl acrylate, with an organic diisocyanate in which one of the two isocyanate groups is more strongly reactive than the other, such as isophorone diisocyanate, is reacted with a phenoxy resin in solvent solution. The alcohol is used in a molar excess of at least about 3% up to 30% to insure the absence of any significant proportion of unreacted diisocyanate. The phenoxy resin which is reacted with is a high molecular weight hydroxy functional polyether having a number average molecular weight above 10,000 and an hydroxy functionality in the range of from about 20 to about 300. The adduct is used in an amount to introduce about 1.5 to about 20 ethylenically unsaturated groups per molecule of the polyether, and the reaction is continued to substantially eliminate unreacted isocyanate functionality.

Abstract: Liquid coating compositions adapted to be cured by exposure to ionizing radiation are disclosed in which a liquid vehicle of coating viscosity having an ethylenically unsaturated portion comprising one or more polyethylenically unsaturated materials adapted to cure on radiation exposure, pigment dispersed in the vehicle, and an acrylate-functional radiation-curable dispersant having free carboxyl group for wetting the pigment and assisting in the stable dispersion of the pigment in the vehicle. This dispersant is an acrylate-functional carboxylic acid amide carrying free carboxyl groups, especially an adduct of a polyacrylate and a stoichiometric deficiency of a primary amine to provide a secondary amine having acrylate functionality, the secondary amine functionality being reacted with a polycarboxylic acid anhydride to form amide groups therewith.

Abstract: An essentially isocyanate-free polyurethane polyurea polyethylenic oligomer is disclosed which is unusually strong and elastic. This oligomer is the reaction product of: (1) organic diisocyanate; (2) a stoichiometric deficiency of difunctional materials reactive therewith and consisting essentially of: (A) diol component selected from polycarbonate diol and polyoxyalkylene glycol, this diol component having a molecular weight of from 200 to 2000; (B) dihydric bisphenol-based alkylene oxide adduct containing from 2-10 alkylene groups per molecule; and (C) a diprimary diamine component selected from alkylene diamine and polyoxyalkylene diamine, this diamine component having a molecular weight of from about 70 to 800. Components (A) and (B) are present in a weight ratio of from 1:4 to 9:1 and component (C) is present to supply from 30 to 60 equivalent percent of the total equivalents of component (2).

Abstract: A radiation-curable liquid coating composition which cures on radiation exposure to form a soft and tough coating and which is adapted for coating optical fiber is disclosed. This composition comprises a polyurethane, polyamide or polyurea oligomer having (1) a molecular weight in the range of about 2000 to about 8000; (2) amide, urea or urethane groups in an amount of one such group for every 300 to 900 units of weight; and (3) polyalkylene polyether, polyalkylene polysulfide or polyalkylene polyester groups in which the alkylene moiety contains 2-6 carbon atoms. The polyether, polysulfide or polyester constitutes about 40% to about 90% by weight of the oligomer, and each end of the oligomer is terminated with a monoethylenically unsaturated addition polymerizable group. From 20% to 50% of the weight of the composition is a radiation-curable monoethylenically unsaturated monomer having a T.sub.g below about 10.degree. C.

Abstract: There is disclosed acrylate-terminated oligomers which are radiation-curable and which can be pigmented with magnetizable power to cure on electron beam exposure to provide superior magnetic recording structures. These oligomers include sulfonic acid groups which improve pigment wetting and which can be included in amide-containing compounds.

Abstract: Liquid coating compositions adapted to be cured by exposure to ionizing radiation are disclosed in which a liquid vehicle of coating viscosity having an ethylenically unsaturated portion comprising one or more polyethylenically unsaturated materials adapted to cure on radiation exposure, pigment dispersed in the vehicle, and an acrylate-functional radiation-curable dispersant having free carboxyl group for wetting the pigment and assisting in the stable dispersion of the pigment in the vehicle. This dispersant is an acrylate-functional carboxylic acid amide carrying free carboxyl groups, especially an adduct of a polyacrylate and a stoichiometric deficiency of a primary amine to provide a secondary amine having acrylate functionality, the secondary amine functionality being reacted with a polycarboxylic acid anhydride to form amide groups therewith.

Abstract: A radiation-curable liquid coating composition which cures on radiation exposure to form a soft and tough coating and which is adapted for coating optical fiber is disclosed. This composition comprises a polyurethane, polyamide or polyurea oligomer having (1) a molecular weight in the range of about 2000 to about 8000; (2) amide, urea or urethane groups in an amount of one such group for every 300 to 900 units of weight; and (3) polyalkylene polyether, polyalkylene polysulfide or polyalkylene polyester groups in which the alkylene moiety contains 2-6 carbon atoms. The polyether, polysulfide or polyester constitutes about 40% to about 90% by weight of the oligomer, and each end of the oligomer is terminated with a monoethylenically unsaturated addition polymerizable group. From 20% to 50% of the weight of the composition is a radiation-curable monoethylenically unsaturated monomer having a T.sub.g below about 10.degree. C.

Abstract: Radiation curable coating compositions, and especially electron beam-curable coating compositions, are disclosed in which magnetizable particles are dispersed in a liquid vehicle comprising a polyethylenically unsaturated polyurethane oligomer which includes a polycarbonate diol, and from 5% to 50%, based on the total weight of unsaturated material, of a polyethylenically unsaturated isocyanurate, such as a triacrylate of tris(2-hydroxyethyl) isocyanurate.

Abstract: Nonvolatile plasticizers are provided which are the carboxyl-functional amide reaction product of: (1) a secondary amine-functional adduct of an acrylate compound, like 2-hydroxyethyl acrylate or a monohydric caprolactone monoacrylate, and about one amine equivalent per acrylate group in the acrylate compound, of an organic primary amine such as a polyoxypropylene monoprimary amine having a molecular weight in the range of about 50 to about 8000; with (2) a dicarboxylic acid anhydride, like phthalic anhydride. These plasticizers have improved wetting properties and are particularly useful in nitrocellulose compositions, such as nail polish.

Abstract: Radiation curable coating compositions, and especially electron beam-curable coating compositions, are disclosed in which magnetizable particles are dispersed in a liquid vehicle comprising an hydroxy functional polyethylenically unsaturated polyurethane having the following structural formula: ##STR1## in which X is an ethylenically unsaturated monomer initially carrying a single hydroxy group, R' is the residue of an at least trifunctional polyol or amino alcohol linking compound, s is a number of 0.8 to 10, t is a number from 1 to 15, and Z is a diisocyanate terminated polycarbonate diol polyurethane oligomer having the following structure: ##STR2## in which R is alkylene having from 1-20 carbon atoms, Q is the residue of an organic diisocyanate; y is at least 1, and R and y are selected to provide a molecular weight for the polycarbonate diol reactant of from 300 to 3000.

Abstract: Optical fibers are coated with a radiation-curable liquid, polyethylenically unsaturated coating composition consisting essentially of an organic polysiloxane having from 2 to 6 reactive side chains each of which carry a functional group providing one reactive site which has been reached to provide a single radiation-curable monoethylenically unsaturated side chain. There are about one such side chain for every 500 to 5,000 units of molecular weight. This provides a prime coating which has a modulus of elasticity at room temperature and at -60.degree. C. below 3000.

Abstract: Liquid coating compositions adapted to be cured by exposure to penetrating radiation are disclosed in which a liquid vehicle of coating viscosity having an ethylenically unsaturated portion comprising one or more polyethylenically unsaturated materials adapted to cure on radiation exposure, pigment dispersed in the vehicle, and an ethylenically unsaturated radiation-curable dispersant containing a carboxyl group for wetting the pigment and assisting in the stable dipsersion of the pigment in the vehicle. This dispersant is a half amide or half ester of an ethylenically unsaturated polycarboxylic acid anhydride, such as maleic anhydride, with an organic compound having a molecular weight of from 100 to 4000 and which contains a single hydroxy group or a single amino group as the sole reactive group thereof.

Abstract: Radiation-curable coating compositions particularly adapted to reduce the adhesion of the radiation-cured coatings to glass optical fibers (and thereby enhance strippability) are disclosed. These comprise a radiation-curable polyethylenic organic compound and from about 2% to about 20% of the coating composition of an organic polysiloxane carrying a plurality of hydroxy-terminated groups which are joined to some of the silicon atoms in the polysiloxane chain by a carbon-to-silicon bond. The polysiloxane reduces the adhesion of the radiation-cured coating to the glass surface of the fiber. Ultraviolet cures using acrylates as the ethylenic group are preferred.