| 摘要 |
Retroreflective sheeting is usually provided as rolls with an adhesive backing for application to rigid road and other signs. Roll-up signs are those small signs having folding frames holding a flexible material placed to caution traffic about temporary workers. On completion of the tasks the frames are folded, and the signs are rolled up for future use. Such signs, contemplated herein, present problems other than flexibility. In addition to weather resistance, durability, and foldability, means for attaching the signs to the stands must be devised. Generally the sign material is provided with pockets. But most plastics cannot be readily sewn. The resulting needle holes weaken the sewn area so that the pocket readily tears out, or at least partially away, from the sign. The usual method for making such signs, then, is to attach the pockets by fusion using heated die elements. The deformation which occurs when the heated die is impressed to bring about the heat fluidization usually weakens the plastic. Herein a long-lasting roll-up sign is provided having durable pockets which are not fusion deformed.
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