Abstract: Microcapsules for smart textile materials, containing an active product and with reactive groups, with the objective of chemically binding the microcapsules to the fibres. The microcapsules contain active products such as PCM (phase change materials), or can be of controlled release of products such as fragrances, essential oils, antibacterial and others with the objective to add specific functional properties to the textile materials. They can be applied by padding and spraying followed by thermofixation. In case of products such as knitwear the application process can also be by exhaustion process, given that the microcapsules acquire affinity towards the fibres and react with the fibres during the process. The chemical bond of the controlled release microcapsules with the fibres confers them a higher resistance to washing than the existing microcapsules glued to the fabric by printing or padding.