The invention relates to a binder or building material on the basis of a synthetic material, like e.g. polystyrene in the form of a monopolymerisate or copolymerisate, or an inorganic polymer, which is available as an absorptive compound from the fragmented synthetic material or inorganic polymer and at least one vegetable oil, vegetable oil constituent or vegetable oil derivative. The binder or building material can be prepared by leaving the synthetic material or the inorganic polymer present in machined or fine-dispersed form to react with the vegetable oil, vegetable oil constituent, or vegetable oil derivative, and leaving the synthetic material or polymer thus modified to react with the identical or an additional vegetable oil, vegetable oil constituent, or vegetable oil derivative. The binder or building material can be used as an adhesive or sealant and as an additive to building materials, to manufacture an essentially homogeneous granulate of high flowability and bulk density, as a constituent of detergents and cleaning agents, and as a precursor or intermediate product for cosmetics and body-care products.