Nowadays additive manufacturing has taken a huge importance in industry. There are fast technologies used to build various objects with more or less all shapes possible. Due to the high accuracy of the manufactured objects, they are used in lots of different industries like aerospace, medicine where precision is needed. Moreover, those technologies allow rapid prototyping, which is a quick way to design new and innovative materials. Polymers are also more and more often used in industries due to their particular properties. They have different mechanical properties than metals or ceramics but their low weight is an advantage. In different areas, polymer is used to save weight of structures, thus its demand has increased a lot. It is thus important to improve mechanical properties of polymers. In this thesis, a particular type of impact modifier, the so-called core-shell particles will be used. Article  says that rubber particles are able to improve mechanical properties: at constant particle size, impact strength versus rubber content curves exhibit a step at a precise rubber content. In this thesis, photopolymers will be processed by stereolithography. It is a kind of additive manufacturing using a laser in UV-range to polymerize resins. As said before, the goal of this thesis is to improve mechanical properties without losing thermal properties. The ideal material would have high elongation at break and high impact strength while its storage modulus remains more or less constant in the temperature range of its application. The first chapter of this thesis is the background where additive manufacturing technologies, photopolymers, toughening mechanisms and technical polymers will be explained in detail. The second chapter is the method which contains all information on the preparation of the formulations, the parameters of the printing, the post-curing and the different tests. The last chapter is dealing with the results.