Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From sulfur-containing reactant
Reexamination Certificate
1998-11-12
2001-03-13
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From sulfur-containing reactant
C528S374000, C528S364000
Reexamination Certificate
active
06201099
ABSTRACT:
BACKGROUND OF THE INVENTION
Star-branched polymers, also known as radial polymers, are characterized by having three or more polymeric arms emanating from a central core. These polymers can be prepared by various polymerization procedures such as anionic, cationic, and free radical mechanisms. The stars are usually formed by using either multifunctional initiators, multifunctional chain transfer agents, or multifunctional coupling agents. The star-branched polymers have unique properties including: narrow molecular weight distributions; low viscosities at low molecular weights or in solution due to their compact structures; high viscosities at high molecular weights due to extensive entanglements.
Heteroarm star polymers have been prepared using free radical methods involving partially capping a polythiol, typically by acetylation, grafting from the uncapped SH groups, removing the blocking group by hydrolysis, and then grafting the second monomer off of the liberated SH groups. U.S. Pat. Nos. 5,399,642 and 5,492,965.
U.S. Pat. No. 5,679,762 discloses the preparation of heteroarm star copolymers by free radical polymerization using sequential addition of monomers. This process relies solely upon the order of addition of monomers for its selectivity.
The present invention improves over the methods of the prior art by using chain transfer agents containing thiol groups with multiple reactivities. Thus, the selectivity is controlled by both the order of addition of the monomers and the composition of the polymercaptan core. Hence, greater control over the blockiness of the heteroarm star results.
SUMMARY OF THE INVENTION
The present invention is directed to multireactivity polymercaptan cores, star-shaped polymers and methods of preparing such polymers. Specifically, the star polymers of the present invention comprise a polyvalent mercaptan core and three or more polymeric arms which extend radially from the core.
The polyvalent mercaptan core comprises three or more thiol groups. In one embodiment at least two of the thiol groups are of different reactivities. Such cores will be referred to as cores of differential reactivity or heterocores.
The polymers of the present invention are prepared by a process which utilizes cores of differential reactivity having three or more SH groups, wherein at least two of the thiol groups have different chain transfer constants. These cores of differential reactivity, act as chain transfer agents in a free radical polymerization process to produce a star polymer.
REFERENCES:
patent: 3364182 (1968-01-01), Griffith
patent: 3769254 (1973-10-01), Anderson et al.
patent: 5391406 (1995-02-01), Ramharack et al.
patent: 5399642 (1995-03-01), Emmons et al.
patent: 5416127 (1995-05-01), Chandran et al.
patent: 5489397 (1996-02-01), Bainbridge
patent: 5492965 (1996-02-01), Emmons et al.
patent: 5498675 (1996-03-01), Emmons et al.
patent: 5536759 (1996-07-01), Ramharack et al.
patent: 5574117 (1996-11-01), Yoshida et al.
patent: 5679762 (1997-10-01), Yoshida et al.
patent: B1 3769254 (1985-02-01), Anderson et al.
patent: 1645232 (1966-11-01), None
patent: 0 448 224 A1 (1991-09-01), None
patent: 0 449 413 A1 (1991-10-01), None
patent: 0 541 272 A1 (1993-05-01), None
patent: 2 294 467 (1996-05-01), None
patent: 9-53059 (1997-02-01), None
patent: WO 96/37520 (1996-11-01), None
Schaefgen and Flory, “Synthesis of Multichain Polymers and Investigation of their Viscosities”, JACS, Aug. 1948, vol. 709, pp. 2709-2718.
Morton, Helminiak, Gadkary and Bueche, Preparation and Properties of Monodisperse Branched Polystyrene,Journal of Polymer Science, vol. 57, pp. 471-482 (1962).
Kauder, “Thols”,Encyclopedia of Chemical Technology, Third Edition, vol. 22, pp. 946-964.
Jérome and Teyssié, Star-Shaped Block Copolymers. IV. Emulsifying Activity in the Water-Oil Emulsions,Journal of Applied Polymer Science, vol. 26, 343-351 (1981).
“Branched Polymers”,Encyclopedia of Polymer Science and Engineering, vol. 2, pp. 478-499.
Simms and Spinelli, “Recent Advances in Group Transfer Polymerization and Their Applications In Coatings”,Journal of Coatings Technology, vol. 59, No. 752, Sep. 1987, pp. 125-131.
Yuan and Di Silvestro, “Polymerization of methyl methacrylate in the presence of polyfunctional chain transfer agents”, Macromol. Chem. Phys. 196, 2905-2913 (1995).
Erickson, Zimmermann, Southwick and Kiibler, “Liquid Reactive Polymers for Radiation Curable High Performance PSAs”,Adhesive Age, Nov. 1995.
Puts and Sogah, “Universal Multifunctional Initiator Containing Orthogonal Reactive Sites . . . ”Macromolecules1997, 30, 7501-7055.
Ullisch and Burchard, “Branching in Free Radical Polymerization Due to Chain Transfer . . . ”,Makromol. Chem., 178, 1427-1437 (1977).
European Coatings Journal, vol. 1-2/98, p. 87.
Gia et al., “Star-shaped block copolymers. II. Microemulsions stabilizers”, Colloid & Polymer Science 257, 1294-1296 (1979).
Harlan Robert D.
Petersen Paul M.
Schoenberg Jules E.
Foulke Cynthia L.
Kaiser Karen G.
National Starch & Chemical Investment Holding Corporation
Truong Duc
LandOfFree
Multireactivity polymercaptans, star polymers and methods of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multireactivity polymercaptans, star polymers and methods of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multireactivity polymercaptans, star polymers and methods of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2448963