Patent ID: 8087828

Claim:
A synthetic resin bag having an easy-opening function, said synthetic resin bag comprising two front and back panel films forming a bag body, said panel films having respective grasping pieces provided on the side of opening of said panel films, characterized by comprising two easy peel tapes having the same longitudinal width perpendicular to the lateral width direction of said bag body and disposed inside of said panel films of the bag body in an opening section thereof over the whole lateral widths thereof, said two easy peel tapes each including an easy peel layer and a thermally adhesive layer, said easy peel layers of said two easy peel tapes faced to each other being weakly adhered to each other so that the weak adhesion faces of said easy peel layers of said two easy peel tapes have lower ends disposed at the same level position while said thermally adhesive layers of said two easy peel tapes being strongly adhered to the inner faces of said panel films of said bag body, respectively so that said thermally adhesive layers have an adhesion width difference of long and short widths in a direction perpendicular to said lateral width direction of said bag body, said strong adhesion portions of said thermally adhesive layers being formed so that they have lower ends shifted relative to each other while said thermally adhesive layer of said easy peel tape having the shorter strong adhesion width has a non-adhesion portion whereby said easy peel layers of said two easy peel tapes can be easily separated on the side of said opening section of said bag body by a force acting in a direction opposite to each other when said grasping pieces are pulled in leftward and rightward directions while said easy peel layers of said two easy peel tapes can be prevented from being separated on the side of an interior section of said bag body corresponding to a section inside of said easy peel tape by a force acting in the surface direction of said weak adhesion face by means of said adhesion width difference between strong adhesion faces of said thermally adhesive layers of said easy peel layer when a pressure is applied from the interior section of said bag body.