| 摘要 |
A pressure threshold sensitive adhesive product which exhibits substantially no adhesive tack except upon the application thereto of a threshold pressure, e.g. about 50 pounds per square inch is disclosed. This adhesive product comprises a substrate having coated thereon a layer of a normally tacky, pressure-sensitive adhesive and a top layer of microspheres, preferably hollow microspheres, in an amount sufficient to cover the immediate adhesive layer. The application of the threshold pressure causes the microspheres to be displaced thereby exposing the normally tacky adhesive. The adhesive product is preferably manufactured by preparing a suspension of the microspheres in the normally tacky adhesive composition, coating the suspension on the substrate and promoting the microspheres to migrate to the top of the suspension and to form the top microsphere layer.
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