Abstract: A process is disclosed for transfer printing thermoplastic materials with thermal diffusion inks. An image is transferred in a heatable press from a paper substrate colored with thermal diffusion inks onto an intermittently moved, fiber-containing carrier material into which the thermal diffusion inks can at first be sublimated then diffused. This fiber-containing carrier material provided with thermal diffusion inks is then transported into the gap between the calender rollers, where it is continuously brought into contact with a thermoplastic melt at an increased temperature so that the thermal diffusion inks penetrate into the thermoplastic melt and at the same time a composite strip made of the fiber-containing carrier material and the thermoplastic melt is formed. The products obtained by this process are suitable for producing a decorative layer on parts of skis or snowboards and on composite materials made of fiber-reinforced plastics.