Use of a prepolymer in transparent thermoplastic compositions, compositions comprising same and uses thereof

A composition comprising:

• from 60 to 99.95% by weight of at least one semicrystalline transparent copolyamide;
• from 0.05% to 20% by weight of at least one prepolymer with a number-average molecular mass from 1000 to 15 000 g/mol, wherein said prepolymer is a monofunctional acid or monofunctional amine the weight proportion of the semicrystalline transparent copolyamide is from 60% to 99.95 and the weight proportion of the prepolymer is from 40% to 0.1%, relative to the sum of the weight of the transparent semicrystalline copolyamide and the weight of the prepolymer;
• from 0 to 20% by weight of one or more additives;
• wherein the composition is free of nucleating agent and is free of impact modifier,
• wherein the composition is formed by dry blending the at least one semicrystalline transparent copolyamide, the at least one prepolymer and the one or more additives together, and wherein the composition has improved crystallization kinetics and reduced warpage and the same or improved transparency properties and the same or improved mechanical properties, when compared with the same composition free of prepolymer.

A process for preparing a composition, wherein the process comprises a step of dry blending a prepolymer with at least one semicrystalline transparent polyamide and optionally at least one additive, wherein

• said at least one semicrystalline transparent polyamide is present in a proportion of from 60% to 99.95% by weight, relative to the sum of the weights of the polyamide and the prepolymer;
• wherein said prepolymer is a monofunctional acid or monofunctional amine,
• said prepolymer being present in a proportion of 0.05% to 20% by weight, relative to the sum of the weights of polyamide and the prepolymer,
• said additive being in a proportion by weight of 0 to 20%;
• the sum of the weights of the polyamide, the prepolymer and optionally the additive being equal to 100%,
• said composition being free of nucleating agent,
• whereby said composition has improved crystallization kinetics and reduced warpage and the same or improved transparency properties and the same or improved mechanical properties, when compared with the same composition free of prepolymer.