Minnesota Mining and Manufacturing Company

Jurgen Klingen

Patrick G Zimmerman

George F Vesley

Donald T Landin

Karl W Kreckel

Wayne K Darvell

Patricia R Konsti

George F Veasley

Phase-separated, polymerized, cellular pressure-sensitive adhesive membranes possessing a high degree of compression recovery comprising from about 70 parts to about 98 parts of an acrylic polymer containing at least about 75 parts of an alkyl acrylate monomer, the alkyl groups of which have an average of 4 to 12 carbon atoms, and from 0 to about 25 parts of a monoethylenically unsaturated polar copolymerizable monomer, and correspondingly, from about 30 parts to about 2 parts of a saturated hydrocarbon elastomer or blend of hydrocarbon elastomers containing at least one segment having a lower glass transition temperature than the acrylic copolymer. The adhesive has at least a first phase and a second phase, the first phase consisting primarily of the elastomer, and at least one phase is a continuous phase. Cellular pressure-sensitive adhesive membranes of the invention have improved low temperature shock resistance over otherwise identical cellular pressure-sensitive adhesive membranes containing no elastomer.

Cellular pressure-sensitive adhesive membrane

A pressure-sensitive adhesive tape can be produced by photopolymerization and yet its pressure-sensitive adhesive layer can have a dark appearance when it contains a pigment or dye plus finely divided hydrophobic silica. As compared to a tape which is identical except for omission of the hydrophobic silica, the adhesive layer of the tape is substantially darker and usually of substantially more intense color. Furthermore, the tape exhibits better adhesive properties than do otherwise identical tapes containing no silica. The pressure-sensitive adhesive preferably is an acrylic pressure-sensitive adhesive and may be filled with glass microbubbles which afford a foamlike appearance and character.

Dark acrylic pressure-sensitive adhesive

Tape products for diverse end users are obtained by applying to a sheet backing a layer of normally tacky and pressure-sensitive adhesive (PSA) containing and completely surrounding resilient non-tacky hollow thermoplastic polymeric microspheres. When the PSA is permanently bonded to the backing and the exposed surface has an irregular contour, a removable and repositionable product results. When the PSA forms a continuous matrix that is strippably bonded to the backing and is 1 mm or more thick, the resultant product is a foamlike transfer tape or foam tape. Depending on the product, the PSA can contain from about 1/5 to about 2/3% of the microspheres by volume.

Pressure-sensitive tape construction incorporating resilient polymeric

By incorporating hydrophobic silica into acrylic pressure-sensitive adhesive tape, the shear strength at elevated temperatures is significantly improved, and adhesion and physical properties are maintained or improved. The hydrophobic silica preferably has a surface area from 50 to 400 m.sup.2 /g. A preferred acrylic pressure-sensitive adhesive layer comprises a copolymer of (a) at least one alkyl acrylate having an average of 4-12 carbon atoms in its alkyl group and (b) from 3 to 20% by weight of copolymerizable monomer having a polar group such as acrylic acid.

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Schwalmtal, Germany

Jurgen Klingen