A unitary absorbent structure comprising an absorbent core (5) having a permanent liquid retention capacity and an acquisition (14) and dispersion layer (16) having a temporary liquid retention capacity, said core (5) comprising absorbent or said acquisition layer (14) and dispersion (16) at least one layer (23) of nonwoven fibrous substrate having a void volume suitable to be penetrated by super absorbent particles (21), said particles (21) having super absorbents a size distribution and being dispersed within the nonwoven fibrous substrate layer (23) according to its particle size distribution gradient along the depth direction or Z direction of said absorbent core (5) or acquisition layers (14) and dispersion (16), characterized in that at least 90% of the super absorbent particles have a particle size diameter in the range of 45 to 850 μm, said absorbent structure comprises less than 4% by weight of fluff and is also covered by a covering layer (22), and wherein the smaller super absorbent particles (21) are able to penetrate, along the Z direction , inside the lower part of the substrate (23) while the larger super absorbent particles (21) remain on the outside or on the surface of the substrate (23).Una estructura absorbente unitaria que comprende un núcleo (5) absorbente que tiene una capacidad de retención permanente de líquido y una capa de adquisición (14) y dispersión (16) que tiene una capacidad de retención temporal de líquido, comprendiendo dicho núcleo (5) absorbente o dicha capa de adquisición (14) y dispersión (16) al menos una capa (23) de substrato fibroso no tejido que tiene un volumen vacío adecuado para ser penetrado por partículas (21) súper absorbentes, teniendo dichas partículas (21) súper absorbentes una distribución por tamaño y estando dispersadas en el interior de la capa (23) de substrato fibroso no tejido conforme a su gradiente de distribución por tamaño de partícula a lo largo de la dirección de profundidad o dirección Z de dicho núc
