Skip to main content

Synthesis of acrylic resins for high-solids coatings by solution and separation polymerization


Conventional solution polymerization under monomer-starved conditions was compared with separation polymerization, also known as monomer-starved, as a method for making acrylic resins with low polydispersity (D=Mw/Mn). Separation polymerization employs aliphatic or cycloaliphatic solvents that are good solvents for the monomers but poor solvents for the resin; thus, the resin separates during polymerization. Various process conditions, initiators, chaintransfer agents, and solvents were studied, focusing mainly on a monomer line-up of methyl methacrylate, styrene, ethyl acrylate, and 2-hydroxy ethyl methacrylate in a 15/15/40/30 weight ratio. Two initiators, t-amyl peroxy 2-ethyl hexanoate and t-butyl peroxy 2-ethyl hexanoate gave about equal, excellent results. 2-Mercapto ethanol was selected as a chain transfer agent. With these ingredients, the separation polymerization method is capable of producing oligomeric acrylic polyol resins with polydispersities (D) of about 1.7 to 1.8 when Mn is in the range 1350 to 1600. These resins have substantially lower solution viscosities than a commercial benchmark resin, which has Mn=1230 and D=2.03. In preliminary tests of 2K polyurethane coatings, the film properties obtained with acrylics made by separation polymerization were, on balance, superior to those obtained with a commercial benchmark resin.

This is a preview of subscription content, access via your institution.


  1. Wright, A.J., “Hydroxyl Functional Acrylics for VOC Compliance,”Eur. Coat. J., 696 (October 1996).

  2. Boatwright, J.H., “Chicago Society Defines ‘Oligomer’,”Journal of Coatings Technology,52, No. 664, 124 (1980).

    Google Scholar 

  3. Wicks, Z.W., Jr., Jones, F.N., and Pappas, S.P.Organic Coatings: Science and Technology, 2nd Ed., John Wiley and Sons, Wiley-Interscience, New York, 21, 1999.

    Google Scholar 

  4. Gerlock, J.L., Mielewski, D.F., Bauer, D.R., and Carduner, K.R., “End Groups in Acrylic Copolymers. 2. Mechanisms of Incorporation of End Groups and Relationship to Photoinitiation Rates,”Macromolecules, 21, 1604 (1988).

    Article  ADS  CAS  Google Scholar 

  5. Ji, C., Huang, Z., Shen, W., Diakoumakos, C.D., and Jones, F.N., “Preparation and Properties of Mar Resistant Coatings by Crosslinking Isophthalate-Based Oligoesters with HMMM,”Polym. Mater. Sci. Eng., 78, 252 (1998).

    Google Scholar 

  6. Munk, P.,Introduction to Macromolecular Science, John Wiley & Sons, New York, 145–155, 1989.

    Google Scholar 

  7. Janowicz, A.H. and Melby, L.R., “Cobalt(II) Chelates as Chain Transfer Agents in Free Radical Polymerization,” U.S. Patent 4,680,352 (1987).

  8. Gray, R.A., “Preparation of Acrylic Oligomers for High-Solids Coatings Using Hydroxy-Functional Mercaptan Chain Transfer Agents,”Journal of Coatings Technology,57, No. 728, 83 (1985).

    CAS  Google Scholar 

  9. O’Driscoll, K.F., “Compositional Heterogeniety in Low Molecular Weight Copolymers as Revealed by Monte Carlo Simulations,”Journal of Coatings Technology,57, No. 705, 57 (1983).

    Google Scholar 

  10. Spinelli, H.J., “The Role of Functionality in Low Molecular Weight, High Solids Acrylic Resins,”Org. Coat. Appl. Polym. Sci., 47, 529 (1982).

    CAS  Google Scholar 

  11. Haggard, R.A. and Lewis, S.N., “Methacrylate Oligomersvia Alkoxide-Initiated Polymerization,”Prog. Org. Coat., 12, 1 (1984).

    Article  CAS  Google Scholar 

  12. Webster, O.W., “Group Transfer Polymerizations,”Polym. Mater. Sci. Eng., 80, 280 (1999).

    Google Scholar 

  13. Georges, M.K., “An Overview of the Nitroxide-Mediated Living-Radical Polymerization Process,”Polym. Mater. Sci. Eng., 80, 283 (1999).

    CAS  Google Scholar 

  14. Hawker, C.J., Elce, E., Dao, J., Volksen, W., Russell, T.P., and Barclay, G.G., “Well-Defined Random Copolymers by a “Living” Free-Radical Polymerization Process,”Macromolecules, 29, 2686 (1996).

    Article  ADS  CAS  Google Scholar 

  15. Wang, J-L., Grimaud, T., and Matyjaszewski, K., “Kinetic Study of the Homogeneous Atom Transfer Radical Polymerization of Methyl Methacrylate,”Macromolecules, 30, 6507 (1997).

    Article  ADS  CAS  Google Scholar 

  16. Kamath, V.R. and Sargent, J.D., Jr., “Production of High-Solids Acrylic Coating Resins with t-Amyl Peroxides: A New Way to Meet VOC Requirements,”Journal of Coatings Technology,59, No. 746, 51 (1987).

    CAS  Google Scholar 

  17. Myers, G.G., “Initiators for High-Solids Polyacrylates Resins: Selection Guidelines and Performance Review,”Journal of Coatings Technology,67, No. 841, 31 (1995).

    CAS  Google Scholar 

Download references

Author information

Authors and Affiliations


Additional information

430 W. Forest Avenue, Ypsilanti, MI 48197.

Polymer and Coatings Program, Department of Materials Science, Shanghai 200433, P. R. China.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Diakoumakos, C.D., Xu, Q., Jones, F.N. et al. Synthesis of acrylic resins for high-solids coatings by solution and separation polymerization. Journal of Coatings Technology 72, 61–70 (2000).

Download citation

  • Issue Date:

  • DOI:


  • Acrylic Resin
  • Atom Transfer Radical Polymerization
  • HEMA
  • Butyl Acrylate
  • Chain Transfer Agent