"For example, a monomer system of about 70% to about 80% styrene and about 20% to about 30% of an acrylate such as butyl acrylate can be made to have a Tg of about 50??? C., while a monomer system of about 80% to about 90% styrene and about 10% to about 20% of an acrylate such as butyl acrylate can be made to have a Tg of about 60??? C. The shell non-crosslinked polymer may have a Tg of at least ab" . . . .