Molding composition based on unsaturated polyesters

Claim 2

Hardenable molding compositions comprising (a) from 5 to 77 parts, by weight, of a "terminally unsaturated" urethane group-free polyester of the formula ##STR2## wherein R 1 represents the difunctional radical reduced by two hydroxyl groups of a polyester which does not contain any α,β-ethylenically unsaturated groups; and X, Y and R represent hydrogen or C 1 -C 6 alkyl, (b) from 20 to 80 parts by weight of a vinyl or vinylidene compound copolymerizable therewith; and (c) from 3 to 25 parts, by weight, of an elastomeric polymer having a glass transition temperature of from 90° to +10° C., a second phase in the form of particles having an average diameter of from 0.1 to 100 μm formed during hardening.

Claim 3

Molding compositions as claimed in claim 1, characterized in that the copolymer of (a) and (b) being formed during hardening has a specific fracture surface energy of >0.5·10 5 , preferably between 0.5·10 5 and 10 6 , ergs/cm 2 .

Claim 4

A process for the production of molding compositions as claimed in claim 1, characterized in that, in a first stage, 1 mole of one or more organic dicarboxylic acids is esterified using from 1.05 to 2.0 moles of one or more organic diols preferably in the melt at from 150° to 220° C., optionally in the presence of conventional inhibitors, with elimination of water and, in a second stage, 1 mole of the resulting preliminary product containing OH-groups is reacted with an approximately equivalent quantity, preferably from 1.9 to 2.2 moles, of at least one α,β-ethylenically unsaturated dicarboxylic acid anhydride, the corresponding unsaturated dicarboxylic acid or the mono-ester thereof in the melt at from about 60° to 140° C. or in the same way as described for the first step and from 5 to 77 parts, by weight, of the resulting "terminally unsaturated" urethane group-free polyester (a) are mixed with from 20 to 80 parts, by weight, of a vinyl or vinylidene compound (b) copolymerizable therewith and from 3 to 25 parts, by weight, of an elastomeric polymer (c).

Claim 5

A process as claimed in claim 3 in which the first stage is carried out in the melt at 150° to 220° C.

Claim 6

A process as claimed in claim 3 in which the second stage is carried out using from 1.9 to 2.2 moles of the anhydride or acid or the mono-ester thereof.

Claim 7

A composition when produced by a process as claimed in claim 3.