3m Innovative Properties Company

Minnesota Mining and Manufacturing Company

Andreas H Graichen

Siegfried Rainer Goeb

Mark F Ellis

Michael Juergens

Karl W Kreckel

Frank Kuester

Siegfried R Goeb

The present invention relates to a method of preparing a pressure-sensitive adhesive comprising the steps of:

Method for preparing a pressure-sensitive adhesive

The present invention relates to a free-radically radiation-curable, solvent-free and printable precursor of a pressure-sensitive adhesive, the precursor comprising: (i) 30-75 wt. % of one or more mono(meth)acrylate functional oligomer compounds at least one of said oligomer compounds comprising at least one urethane bond, (ii) 0-15 wt % of one or more poly(meth)acrylate functional oligomer compounds, (iii) 5-45 wt. % of one or more monomer compounds comprising one ethylenically unsaturated group, (iv) 0-5 wt. % of one or more monomer compounds comprising two or more ethylenically unsaturated groups, and (v) an effective amount of one or more free radical photoinitiators, wherein the percentages which are percentages by weight with respect to the mass of the precursor, are selected so that the precursor has a dynamic viscosity at 20&#xb0; C. and at a shear rate of 100 sof between 300 to 15,000 mPa&#xb7;s.

Free-radically radiation-curable, solvent-free and printable precursor of a pressure-sensitive adhesive

A process for crosslinking a melt-processed polymer composition comprises the steps of (a) forming a polymerizable mixture comprising (i) at least one monoethylenically-unsaturated monomer or prepolymer and (ii) at least one monoethylenically-unsaturated, blocked mono- or polyisocyanate that is thermally stable at a selected melt processing temperature range and that is thermally deblockable at and above a deblocking temperature that is higher than the selected melt processing temperature range; (b) exposing the polymerizable mixture to transmissive energy to polymerize the mixture to form a polymer composition comprising polymerized units derived from the blocked mono- or polyisocyanate; (c) melt processing the polymer composition at the selected melt processing temperature range to form a melt-processed polymer composition; and (d) during melt processing or thereafter, increasing the temperature of the melt-processed polymer composition to the deblocking temperatures in the presence of at least one isocyanate-reactive crosslinking agent, to effect crosslinking of the melt-processed polymer composition.

Crosslinking process

A pressure-sensitive adhesive is obtainable by a process comprising polymerizing

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Hilden, Germany

Andreas H Graichen