Rosin-fatty acid vinylic polymers as sizing compositions

A rosin-fatty acid vinylic polymer surface sizing composition prepared by the process of:

• (A) reacting in an addition polymerization reaction:
• (1) about 20.0% to about 60.0% by total weight of the reactants of a fatty acid rosin mixture comprising:
• (a) about 10.0% to about 90.0% by total weight of the mixture of fatty acid, and
• (b) about 10.0% to about 90.0% by total weight of the mixture of rosin;
• and
• (2) about 40.0% to about 80.0% by total weight of the reactants of a monomer mixture comprising:
• (a) about 15.0% to about 45.0% by total weight of the mixture of a member selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, and combinations thereof,
• (b) about 55.0% to about 85.0% by total weight of the mixture of a member selected from the group consisting of vinylic monomers and combinations thereof,
• (c) about 0.5% to about 5.0% by total weight of the mixture of a polymerization initiator,
• (d) up to about 4.0% by total weight of the mixture of a chain transfer agent, and
• (e) up to about 30% by total weight of the mixture of a hydrocarbon solvent, at a temperature in the range of about 135° C. to about 175° C. to produce a rosin-fatty vinylic polymer having a weight average molecular weight in the range of about 4,000 to about 12,000;
• and
• (B) dispersing the rosin-fatty vinylic polymer in water;
• to produce the surface sizing composition.