A method for closing a valved sack having one or more layers of flexible material. The valved sack has a filling opening which is closed after filling the valved sack. The filling opening is formed by opposite layers of material, which when closing the valved sack, are on top of one another and are undetachably joined. The method involves closing the filling opening by joining the layers of material which are on top of one another by plastic deformation without applying heat. A valved sack formed by the method is also described.

_ um método para closing um valved sack t um ou mais camada flexível material. _ valved sack t um filling abertura que est closed após filling valved sack. _ filling abertura est d forma oposto camada material, que quando closing valved sack, est alto um outro e est undetachably junt. _ método envolv closing filling abertura joining camada material que est alto um outro plástico deformação sem applying calor. _ um valved sack d forma método est também descrev. _