| I.P Abstract & Summary |
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. |
