| 摘要 |
This invention relates to the application of a treatment agent to an air permeable substrate by forming a foam of a liquid containing or constituting the treatment agent and applying the foam to the substrate and causing or allowing the foam to transit the substrate and to be removed from the other side thereof in which process the foam is applied in an excess defined as a ratio of the foam transit liquid content of the material in which case the amount of treatment agent taken up by the substrate will be dependent solely on the concentration of the agent within the foam and not by the volume of the foam applied and further the amount of agent taken up by the substrate is substantially independent of the initial water or liquid content of the substrate. |
