| 摘要 |
Easy-to-open plastic bag has pair of opposed walls (2) made of layers of synthetic resin film which are heat sealed together around their edges thus forming a bag body (A). A tear string (4) including a core string and concentric adherent outer heat-fusing layer is heat fused to the inside surface of one wall through its entire length along a line which is intended to become a transverse opening, one end of the string extending into the fused border region (3) of the bag between the two walls. A U-shaped score (12) is formed in the border adjacent the end of the string, the score including a round cut (12a) near the outer edge of the border and a pair of side cuts (12b) symmetrically disposed on opposite sides of the string terminating near the inner edge of the border. An opening (13) extends transverse to the tear string between the inside of the bag and the inner ends of the side cuts, the tear string passing through its centre. The opening defines a pulling tab (7) in the border region together with the U-shaped score. The length of the opening (L1) transverse to the string is far greater than the distance (D) between the inner ends of the side cuts and the edge of the opening closest to the interior of the bag converges on the string from both sides to meet it at less than 90 deg. (7pp Dwg.No 4/8)
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