| 摘要 |
<p>1312850 Coated products MINNESOTA MINING & MFG CO 21 Jan 1971 2886/71 Heading B2E [Also in Division B5] A substrate, which may be a temporary carrier, is provided on one or both surfaces with a tacky pressure-sensitive adhesive having distributed therein a number of microscopic closed cells of 30-300 microns effective diameter, the cells giving a void volume of the adhesive layer of 25-85%. The microcellular adhesive is prepared by uniformly distributing in a solution of pressure-sensitive adhesive from 2-15% by weight of a blowing agent and 1-10% of a nucleating agent such as fume silica and heating. The adhesive may be an iso-octyl acrylate/acrylic acid copolymer or a butadiene-styrene block copolymer optionally together with a polyterpene resin or may be prepared from crude rubber, wood rosin, polyterpene and B-stage phenol-formaldehyde resin. The substrate may comprise aligned polymeric or glass fibres, a non-woven paperlike web of rayon fibres bonded with polyvinyl alcohol, silicone release-coated kraft paper or biaxially oriented polyethylene terephthalate film, or may be one of two substantially but not completely parallel surfaces between which the adhesive is disposed. The adhesive solution may be applied to the substrate directly or may be applied to a release-coated surface of a kraft paper and dried, the paper laminated on the adhesive side with a substrate, a second adhesive layer applied to the other releasecoated surface of the paper and dried and the tape wound up and then unwound to transfer the second adhesive layer to the free face of the substrate. Prior to foaming, the adhesive solution may be interposed between panels 31 and 32 which are then rivetted at 33 and the adhesive foamed to the microcellular state by means of a hot air gun. Alternatively, a substrate coated on each surface with the microcellular adhesive may be interposed between two surfaces.</p> |
