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US 9,803,114 B2Granted
Acrylic adhesive composition with controlled molecular weight
Assignee3M Innovative Properties Company
InventorsSung-Won Ha, Babu N. Gaddam, Mark F. Ellis, Hae-Seung Lee, John R. Jacobsen
Life of this patent
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Abstract
A method for preparing an acrylate adhesive is provided by the steps of partially polymerizing a monomer mixture to provide a syrup polymer composition having a high molecular weight solute copolymer. This first syrup composition is again polymerized to provide a second syrup polymer composition having a low molecular weight copolymer. The second syrup polymer composition is provided with a crosslinking agent and further polymerized to provide the adhesive composition.
Claims19
A method of preparing an acrylic adhesive copolymer comprising the steps of:
- a) partially polymerizing a (meth)acrylate monomer mixture to a conversion of 0.1 to 25% to produce a first syrup copolymer comprising a high Mw solute copolymer having a Mw of 300,000 to 3,000,000, and unreacted solvent monomer,
- b) add a chain transfer agent and an initiator to the first syrup and partially polymerizing to produce a second syrup polymer comprising the high Mw solute copolymer, a low Mw solute copolymer having a Mw of 300-300,000, and unreacted solvent monomer;
- c) quench the chain transfer agent, and add a crosslinking agent, a photoinitiator and an optional tackifier and photopolymerizing the mixture to produce an adhesive copolymer.
Dependencies are inferred from the claim text.