| 摘要 |
<p>Methods for preparing a polymer emulsion that can be utilized as a pressure-sensitive adhesive are disclosed. The emulsion polymer pressure-sensitive adhesives have substantially Newtonian-like flow characteristics. The basic method for preparation of the polymer emulsions is characterized by the steps of: combining, in an agitated reaction vessel, an alkali-soluble or an alkali-dispersible polymeric resin with water and an effective amount of an alkaline material for forming either a resin-containing alkaline solution or a resin-containing alkaline dispersion, wherein at least about 6 weight percent up to about 30 weight percent of the polymeric resin is prepared from monomers selected from the group consisting of a polymerizable carboxylic acid, a polymerizable acid anhydride, and a polymerizable ester or a polymerizable partial ester of an inorganic acid, and wherein the polymeric resin further includes a polymerizable vinyl monomer selected from the group consisting of acrylic acid esters and derivatives thereof, methacrylic acid esters and derivatives thereof, styrene, alpha-methyl styrene, vinyl toluene, and combinations thereof; subjecting the agitated reaction vessel contents to an inert atmosphere and maintaining the agitated reaction vessel contents at a predetermined reaction temperature; adding to the agitated reaction vessel an emulsion-polymerization initiator and, a predetermined time thereafter, further adding to the agitated reaction vessel one of a first emulsion-polymerizable monomer mixture and a second emulsion-polymerizable monomer mixture, wherein the relative amounts of initiator and said one of the first and a second emulsion-polymerizable monomer mixtures are effective for initiating emulsion-polymerization of said one monomer mixture in the presence of the polymeric resin, and wherein at least about 40 weight percent of each of the first and second monomer mixtures is selected from the group consisting of at least one alkyl acrylate monomer having an alkyl group with from 2 to 20 carbon atoms, styrene, alpha-methyl styrene, tetraethylene glycol diacrylate, hydroxyethyl methacrylate, methyl methacrylate, propyl methacrylate, hexyl methacrylate, vinyl acetate, and combinations thereof; and, a predetermined time thereafter, further adding to the agitated reaction vessel, over a predetermined time period, the other of the first and second emulsion-polymerizable monomer mixtures; and thereafter, maintaining the agitated reaction vessel contents at the predetermined reaction temperature for a predetermined time period, for producing a polymer emulsion that can be utilized as a pressure-sensitive adhesive.</p> |
