US 6,476,170 B1 · Solid acrylic resin using a continuous tube reactor

Abstract

Described is a process for making acrylic resins suitable as polymeric surfactants used in emulsion polymerization, as pigment grinding resins and for preparing dispersions used as overprint varnishes. The feedstock is styrene, α-methyl styrene, acrylic acid and a polymerization initiator and is preferably free of solvent. This mix is passed through a continuous tube reactor run at a controlled range of pressure and relatively low residence time and temperature. Optimally, when the polymer/unreacted monomers blend exits the reactor and is devolatilized, the recovered monomers are used to make up part of the feedstock.

Claims47

Dependent claims

An acrylic resin produced by the process comprising the steps of:

(a) charging into a continuous tube reactor, a feedstock comprising at least one acrylic monomer and a polymerization initiator;
(b) maintaining a flow rate through the reactor sufficient to provide a residence time of the feedstock in the reactor of about one minute to about one hour;
(c) maintaining a pressure of about 80 psig to about 500 psig;
(d) maintaining the resulting molten resin mixture with a heat transfer medium at a temperature of about 180° C. to about 260° C.;
and
(e) devolatilizing the molten resin mixture exiting the reactor to remove unreacted monomer to provide an acrylic resin upon cooling;
the acrylic resin having an acid value of 242 to 395, a glass transition temperature of 89° C. to 129° C., and being substantially solvent free.

4 more elements

Dependencies are inferred from the claim text.

Solid acrylic resin using a continuous tube reactor

Life of this patent

Solid acrylic resin using a continuous tube reactor

Life of this patent

Abstract

Claims47