Tea bag

Abstract

In the present invention, water-expandable material constituting a tea bag satisfies the condition that the expansion coefficient in a first direction is larger than an expansion coefficient in a second direction perpendicular to the first direction or that a magnitude of contraction coefficient in the second direction is larger than a magnitude of contraction coefficient in the first direction perpendicular to the second direction. Accordingly, the tea bag prevents tea from dissolving any further in water after a predetermined period of time has elapsed, thereby maintaining the deep flavor of the tea for a long time. The present invention presents various other examples of the water-expandable material.

1 - 7 . (canceled) 
     
     
         8 . A tea bag containing tea therein, wherein the tea bag includes water-expandable material that is provided in a deformed state by plastic processing and allows a flow of water and that returns to its original shape and blocks a flow of water when it is in contact with water for a predetermined period of time. 
     
     
         9 . A tea bag containing tea therein, wherein the tea bag includes water-expandable material; and
 wherein the water-expandable material has a multilayer structure in which a second portion expands more than a first portion to obstruct the flow of water when a predetermined time has elapsed after contact with water, the first portion forms the core portion of the water-expandable material, and the second portion forms a periphery portion surrounding the core portion.   
     
     
         10 . (canceled) 
     
     
         11 . The tea bag of  claim 9 , wherein the water-expandable material includes a fibrous material. 
     
     
         12 . The tea bag of  claim 9 , where the periphery portion formed by the second portion has a two- or more-layer structure. 
     
     
         13 . A tea bag containing tea therein, wherein the tea bag includes water-expandable material, and wherein the water-expandable material has a multilayer structure in which a first portion contracts more than a second portion when a predetermined time has elapsed after contact with water, so that a cross-sectional area of each path through which water passes is reduced to obstruct a flow of water, the first portion forms a core portion of the water-expandable material, and the second portion forms a periphery portion surrounding the core portion. 
     
     
         14 . The tea bag of  claim 13 , wherein the water-expandable material includes a fibrous material. 
     
     
         15 . The tea bag of  claim 13 , where the periphery portion formed by the second portion has a two- or more-layer structure.