Self-closing ventilation insert and method for producing it

A shoe comprising a sole and a top portion and a self-closing ventilation insert, wherein the ventilation insert is arranged in or attached to the sole and/or the top portion, which ventilation insert comprises

• a core element having
• a first air-permeable and liquid permeable layer,
• an absorber which is arranged on the first air-permeable layer and swells up and expands on contact with liquid,
• a second air-permeable and liquid permeable layer,
• and
• layers that are at least partially liquid permeable and at least partially air permeable, which layers comprise
• a first covering above the first air-permeable layer,
• a second covering above the second air-permeable layer,
• a first backing layer on the first covering,
• a second backing layer on the second covering,
• wherein the first and second coverings and/or the first and second backing layers compress the air-permeable layers together in partial areas and form a chamber structure, such that the maximum expansion of the absorber upon contact with liquid is limited by the chamber structure and the absorber is compacted thereby as it swells up, wherein the swelling and compacting absorber fills the chamber thereby closing the ventilation insert,
• wherein the core element of the ventilation insert is formed in one piece from the first and second air-permeable and liquid-permeable layers and the absorber layer, and optionally the first and second coverings, are designed in one piece,
• wherein the at least one of the first or second backing layers forms a protective grid or a protective layer which protects the ventilation insert from damage,
• and wherein the absorber layer has a smaller diameter than the chamber formed by the first and second coverings and/or the quantity of dry absorber is selected so that the chamber is air permeable when the absorber is dry.