Steam-releasing flat pouch

Abstract

The steam-releasing flat pouch comprises a seal part, a steam-releasing seal part, and a steam discharge part. The seal part seals stacked sheets. The steam-releasing seal part is located in the inner parts of the sheet inside the seal part, and is configured to join parts of the sheet so that they are not continuous with the seal part. The steam discharge part is formed in the steam-releasing seal part and configured not to allow communication with the outside when the steam-releasing seal part is not peeled, and to allow communication with the outside when the steam-releasing seal part is peeled. The steam-releasing seal part includes an anterior peeling part including a part that peels apart first as the pressure increases, and a posterior peeling part including a part that peels apart last. The width of the posterior peeling part is smaller than the width of the anterior peeling part.

What is claimed is: 
     
         1 . A steam-releasing flat pouch comprising:
 a seal part configured to seal stacked sheets so as to form a storage space for storing contents;   a steam-releasing seal part joining parts of the sheet respectively located in inner parts of the sheet so that the joined parts are not continuous with the seal part, each inner part being a part of the corresponding sheet inside the seal part; and
 a steam discharge part formed in the steam-releasing seal part and configured not to allow the storage space to communicate with the outside when the steam-releasing seal part is not peeled apart, and to allow the storage space to communicate with the outside when the steam-releasing seal part is peeled apart, wherein: 
 the steam-releasing seal part includes an anterior peeling part including a part that peels apart first in the steam-releasing seal part as a pressure in the storage space increases, and a posterior peeling part including a part that peels apart last in the steam-releasing seal part; and 
 a width of the posterior peeling part in a direction different from a direction in which peeling of the steam-releasing seal part proceeds is smaller than a width of the anterior peeling part in the direction different from the direction in which the peeling proceeds. 
   
     
     
         2 . The steam-releasing flat pouch of  claim 1 , wherein:
 the posterior peeling part is formed so that the width thereof becomes narrower in the direction in which the peeling proceeds.   
     
     
         3 . The steam-releasing flat pouch of  claim 1 , wherein:
 the steam discharge part includes a cut or an aperture penetrating one of the stacked sheets, and is formed so as to extend in the direction in which the peeling proceeds.   
     
     
         4 . The steam-releasing flat pouch of  claim 1 , further comprising:
 a guide part constituting a guide for separating the sheet; and   a part of the seal part in order to open the storage space closed by the seal part, wherein:
 the steam-releasing seal part is provided in parts of the sheet that are separated by the guide part. 
   
     
     
         5 . The steam-releasing flat pouch of  claim 1 , wherein:
 a dimension of the steam discharge part in the direction in which the peeling proceeds is 12.5% or larger of a dimension of the steam-releasing seal part in the direction in which the peeling proceeds.   
     
     
         6 . The steam-releasing flat pouch of  claim 1 , wherein:
 a dimension of the steam discharge part in the direction in which the peeling proceeds is 62.5% or smaller of a dimension of the steam-releasing seal part in the direction in which the peeling proceeds.   
     
     
         7 . The steam-releasing flat pouch of  claim 1 , further comprising:
 the contents stored in the storage space.