摘要:
The invention concerns a cross-linked polymer built up from a polymerization product of a highly unsaturated polymer (a) and a polysiloxane (b) with terminal or pendentive hydrosilane groups in such a way that numerous unsaturated carbon-carbon bonds remain intact, at least one vinyl monomer optionally being grafted to these bonds. The invention also concerns methods of producing the cross-linked polymers, as well as moulded products, in particular contact lenses, biomedical articles and artifical corneas consisting completely or substantially of such cross-linked polymers, and the use of the polymers to coat the surfaces of moulded products.
摘要:
The invention concerns NCO-terminated vinyl telomers which are particularly suitable for use as surface-modifying agents and as coating materials, but also in the production of polymerizable compounds or block copolymers which react to give polymers which can be used to manufacture moulded articles, in particular contact lenses. The NCO-terminated vinyl telomers proposed are compounds of formula (I) O=C=N-PI*-(-A-)-p-Ra in which PI* is a bivalent photo-initiator group; A is a bivalent substituted 1,2-ethylene group derived from a copolymerizable vinyl monomer by replacing the vinyl double bond by a simple bond, each of the Ra groups, independently of each other, is a monovalent group suitable for use as chair terminator in a polymerization reaction; and p is a whole number from 3 to 500. The vinyl telomers carrying the NCO groups are of use in the production of macromers as well as block, comb, star and graft copolymers, preferably for the manufacture of contact lenses. These telomers are also of use in coating various types of surface, in particular the surfaces of contact lenses.
摘要:
A continuous process for the preparation of highly stable, finely divided, low viscosity polymer polyols of small average particle size wherein in the first step an intermediate is prepared by reacting (1) a mixture of styrene and acrylonitrile in a mixture of (2) a polyoxyalkylene polyether polyol and (3) a macromer in the presence of (4) a free radical initiator, (5) a solvent having moderate chain transfer activity and optionally (6) a reaction moderator at a temperature of at least 100°C, such that the intermediate contains a high level of macromer, at least about 12% and preferably at least about 15% with respect to the polyol mixture and the solids content of the intermediate is less than about 30%, preferably less than about 25% and at least about 15% by weight. The intermediate, which functions as a seed for further polymerization, is then further reacted in one or more stirred-tank reactors in series with a mixture of styrene and acrylonitrile in a polyol and optionally a macromer, in the presence of solvent, initiator and a reaction moderator which are distributed among the remaining reactors.
摘要:
This invention provides novel methods for the formation of biocompatible membranes around biological materials using photopolymerization of water soluble molecules. The membranes can be used as a covering to encapsulate biological materials or biomedical devices, as a "glue" to cause more than one biological substance to adhere together, or as carriers for biologically active species. Several methods for forming these membranes are provided. Each of these methods utilizes a polymerization system containing water-soluble macromers, species which are at once polymers and macromolecules capable of further polymerization. The macromers are polymerized using a photoinitiator (such as a dye), optionally a cocatalyst, optionally an accelerator, and radiation in the form of visible or long wavelength UV light. The reaction occurs either by suspension polymerization or by interfacial polymerization. The polymer membrane can be formed directly on the surface of the biological material, or it can be formed on material which is already encapsulated.
摘要:
On décrit des polymères dispersés comprenant des microparticules stabilisées avec deux sortes de stabilisateurs stériques. Le premier stabilisateur est un polymère essentiellement linéaire pourvu d'une extrémité fixée à la microparticule. Le second stabilisateur est un polymère greffé ou à structure en peigne comportant un squelette acrylique à chaînes latérales. Ce stabilisateur, faisant contraste avec le premier stabilisateur, peut être fixé à la partie centrale à l'aide d'une pluralité de groupes fonctionnels placés le long du squelette du polymère greffé.
摘要:
L'invention concerne un procédé d'obtention de surfaces mates, selon lequel on applique tout d'abord une première couche de vernis ayant une première épaisseur puis, sur cette première couche, au moins une deuxième couche de vernis, au moins la couche appliquée en dernier renfermant un agent de matage et présentant une épaisseur de film sec inférieure à la granulométrie moyenne de l'agent de matage. Le procédé est caractérisé en ce que les couches de vernis appliquées sont durcies par rayonnement ionisant.
摘要:
Adding a dye with a visible color to an ultraviolet radiation curable composition which contains a photoinitiator which generates free radicals upon exposure to ultraviolet radiation produces a composition which changes visible color upon exposure to ultraviolet radiation. This visible color change indicates that the composition has cured. This cure indication is useful for compositions curable by ultraviolet radiation in the electronics and electrical industry.
摘要:
Disclosed herein is a hard coating film, which exhibits high hardness and excellent properties without a supporting substrate. The hard coating film can find useful applications in various fields thanks to its excellent hardness, scratch resistance, transparency, durability, light resistance, light transmittance, and the like.