Ciba-Geigy Corporation

Ciba Specialty Chemicals Corporation

Urs Gruber

Frans Setiabudi

Elvio Manso

Sameer H Eldin

Friedrich Stockinger

Gerd Greber

Imre Forgo

Aloysius H Manser

Robert Peter Peyer

Rene Huwyler

Hans-Peter Kriemler

Curable suspensions of an epoxy resin formulation comprising

Core/shell polymer toughener suspended in epoxy resin

The invention relates to a substantially solventless curable resin composition, in particular for the fabrication of prepregs, which contains more than 45% by weight of substances which are solid at ambient temperature at least or at lower temperature, and which, in addition to comprising customary modifiers, comprises solid epoxy resins or a mixture of liquid and solid epoxy resins, at least one initiator which is sensitive to UV radiation for the polymerisation of the epoxy resins and has the formula I ##STR1## wherein a and b are each independently of the other 1 or 2, R.sup.1 ist a .pi.-arene, R.sup.2 is a .pi.-arene, an indenyl anion or a cyclopentadienyl anion, [X].sup..crclbar. is an anion [LQ.sub.m ].sup..crclbar. or the anion of a partially fluorinated or perfluorinated aliphatic or aromatic sulfonic acid, L is B, P, As or Sb, Q is F, with the proviso that some of the radicals Q may also be hydroxyl groups, and m is the valency of L increased by one, and at least one further compound which contains one or more than one carboxyl group, which composition, by heating to a temperature in the range from 60.degree. to 140.degree. C., excluding UV light and without the addition of a solvent, is convertible into a liquid state, and, by cooling to a temperature not exceeding ambient temperature and excluding UV light, can be convened from said liquid state into a solid composition which is chemically substantially still unchanged and has a softening point of -3.degree. C. and higher, and which is tack-free or substantially tack-free at ambient temperature. Prepregs can be fabricated from these compositions in simple manner without the use of solvents.

Solventless curable resin composition, in particular for the fabrication

Hardenable mixtures comprising (a) an epoxide resin, (b) a latent epoxide resin hardener which starts to react only at a temperature of at least 80.degree. C. (measured by DSC at a heating rate of 10.degree. C./minute), (c) an amine having at least one amine hydrogen and (d) a thiol having at least one SH group, either the amine (c) having at least two hydrogen atoms bound to one or more nitrogen atoms or the thiol (d) having at least two SH groups, and the difference between the reaction maxima in the DSC diagram at a heating rate of 10.degree. C./minutes being at least 30.degree. C., are suitable for the production of crosslinked products, especially for the production of flexible prepregs having a non-critical B stage and a very good storability.

Hardenable epoxide resin mixtures containing a latent hardener, an amine

A fibrous composite structure impregnated with a solvent-free, curable epoxy resin matrix and comprising

Fibrous composite structure impregnated with a solvent-free curable

Prepregs which are tacky to dry to the touch can be prepared by impregnating a solid reinforcing material with a liquid, solvent-free composition containing (a) an epoxide resin, (b) a photopolymerizable compound, (c) a heat-activatable curing agent for the epoxide resin (a) and, if appropriate, a photopolymerization catalyst for the photopolymerizable compound (b), and the composition is exposed to actinic radiation. The composition solidifies thereby to give an essentially solid layer as the result of photopolymerization of the photopolymerizable compound, whereas the epoxide resin remains substantially in a heat-curable state. In accordance with the invention, a substituted or unsubstituted aliphatic, cycloaliphatic or araliphatic amine is used as the heat-activatable curing agent (c), and the photopolymerizable compound (b) is employed in such a ratio to the heat-curable component (a) that, after irradiation with actinic light, the composition can still be shaped by thermoplastic methods. The prepregs thus obtained are suitable for the production of reinforced composite materials, such as skis, tennis rackets or car body components by hot-curing.

Process for the preparation of prepregs, and the reinforced composite

Fibre composite systems, in particular fibre composite laminates, can be prepared advantageously from a fibre composite impregnated with a curable epoxide resin matrix containing:

Fibre composite materials impregnated with a curable epoxide resin matrix

Crosslinked polyacrylamides containing silyl groups are disclosed which are prepared in a simple and economical manner by polymerizing silylated acrylic acid amides in the presence of a crosslinking agent such as 1,4-butanediol-diacrylate. The resultant crosslinked silylated polyacrylamides are insoluble in customary solvents and are useful for the transfer of silyl groups to compounds which contain at least one mobile hydrogen atom. They may be employed, e.g., in gas chromatography, mass spectroscopy and chemical syntheses (for instance for the introduction of protective silyl groups).

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Arlesheim, Switzerland

Urs Gruber