Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-08-10
2002-08-20
Wu, David W. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S270000, C524S764000, C524S773000, C525S054420, C526S216000, C526S238300, C526S307000, C526S319000, C526S320000
Reexamination Certificate
active
06437033
ABSTRACT:
FIELD OF INVENTION
This invention relates to novel rosin-fatty acid vinylic polymer compositions and the process for preparing them. In particular, the invention relates to novel rosin-fatty acid vinylic polymer compositions which exhibit properties that make them useful as support resins for ink and overprint formulations and as additives for formulating various coating compositions.
BACKGROUND OF THE INVENTION
It is highly desirable that ink and overprint formulations utilized for graphic art applications possess certain high performance characteristics. As typical surfactant-based emulsion polymerization products do not have the desired rheology properties for these applications, it is common practice to add a support resin in place of, or in addition to, the surfactants. These water and alkaline soluble (at pHs of about 8) resins are added to the emulsion polymerization reaction to improve the stability and Theological properties of the latex. Improved stability results from adsorption of the resin on the surface of the particles and the increased viscosity of the emulsion.
The traditional process for producing polymer support resins is well known (see generally U.S. Pat. Nos. 4,839,413 and 5,216,064, which are hereby incorporated by reference). Commonly a solution polymerization reaction is employed wherein styrenic monomer and acrylic acid is mixed with a hydrocarbon solvent, a polymerization initiator, and a chain transfer agent. Upon completion of the reaction, the solution is stripped of the solvent to yield the acrylic polymer. The polymer is then available for use as a support resin when dissolved in an ammoniacal water solution.
However, major problems exist with the traditional methods of producing support resins. For example, these methods require the use of environmentally adverse hydrocarbon solvents. Moreover, as these solvents are not usable or desirable in water-based ink or overprint formulations, the solvents must be stripped from the resulting acrylic polymers (thereby causing a yield loss). This stripping step also adds expense to the process due to both the loss of yield and the energy consumed in performing the stripping. Also, these methods must utilize chain transfer agents to regulate the molecular weight of the resulting support resin.
Therefore, an object of this invention is to solve these major problems by disclosing a method of producing rosin-fatty acid vinylic polymer compositions.
Another object of this invention is to disclose rosin-fatty acid vinylic polymer compositions which exhibit properties that make them useful as support resins in water-based ink, overprint, and other coating formulations.
SUMMARY OF THE INVENTION
The objects of this invention are met via a method that employs rosin and fatty acid to act as solvents in the polymerization reaction of the acrylic monomers, thereby producing rosin-fatty acid vinylic polymer compositions which are useful as support resins in water-based ink, overprint, and other coating applications. As this method does not require the use of hydrocarbon solvents, the need for solvent stripping is eliminated. Also, the polymerization reaction can be conducted at higher temperatures (i.e., up to boiling point of fatty acid) than traditional solution polymer methods, thereby allowing the practitioner to utilize smaller amounts of free radical initiators. Furthermore, the practitioner is able to regulate molecular weight without the use of chain transfer agents, thereby both reducing costs and avoiding the production of unpleasant odors associated with such agents. Moreover, the fatty acid and rosin can function as a reactive diluent to impart flexibility to the support resin.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The method for producing rosin-fatty acid vinylic polymer compositions comprises reacting in an addition polymerization reaction:
(A) about 20.0% to about 60.0% by total weight of the reactants of a fatty acid rosin mixture comprising:
(1) about 10.0% to about 90.0% by total weight of the fatty acid rosin mixture of fatty acid, and
(2) about 10.0% to about 90.0% by total weight of the fatty acid rosin mixture of rosin; and
(B) about 40.0% to about 80.0% by total weight of the reactants of a monomer mixture comprising:
(1) about 15.0% to about 45.0% by total weight of the monomer mixture of a member selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, and combinations thereof,
(2) about 55.0% to about 85.0% by total weight of the monomer mixture of a member selected from the group consisting of vinylic monomers and combinations thereof,
(3) about 0.5% to about 5.0% by total weight of the monomer mixture of a polymerization initiator,
(4) up to about 4.0% by total weight of the monomer mixture of a chain transfer agent, and
(5) up to about 30% by total weight of the monomer mixture of a hydrocarbon solvent,
at a temperature in the range of about 135° C. to about 175° C. to produce a rosin-fatty acid vinylic polymer composition having a weight average molecular weight in the range of about 4,000 to about 12,000.
Preferred rosin-fatty acid vinylic polymer compositions are the products of the process of reacting in an addition polymerization reaction:
(A) about 20.0% to about 60.0% by total weight of the reactants of a fatty acid rosin mixture comprising:
(1) about 20.0% to about 50.0% by total weight of the fatty acid mixture of fatty acid, and
(2) about 50.0% to about 80.0% by total weight of the fatty acid mixture of rosin; and
(B) about 40.0% to about 80.0% by total weight of the reactants of a monomer mixture comprising:
(1) about 20.0% to about 25.0% by total weight of the monomer mixture of a member selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic anhydride, and combinations thereof,
(2) about 60.0% to about 70.0% by total weight of the monomer mixture of a member selected from the group consisting of vinylic monomers and combinations thereof,
(3) about 1.0% to about 3.0% by total weight of the monomer mixture of a polymerization initiator,
(4) about 0.5% to about 2.0% by total weight of the monomer mixture of a chain transfer agent, and
(5) about 1.0% to about 4.0% by total weight of the monomer mixture of a hydrocarbon solvent,
at a temperature in the range of about 135° C. to about 175° C. to produce a rosin-fatty acid vinylic polymer composition having a weight average molecular weight in the range of about 4,000 to about 12,000.
The addition polymerization reaction used to produce the rosin-fatty acid vinylic polymer is a melt polymerization reaction in which no water is employed. Reaction temperatures suitable for use in the present method are within the range of about 135° C. to about 175° C.; with the preferred temperatures being in the range of about 140° C. to about 170° C.
The rosin and fatty acid function as solvents in the polymerization reaction of the acrylic monomers. Additionally, while a portion of the fatty acid and the rosin component remains unreacted, some of the fatty acid and rosin becomes graft polymerized onto the acrylic. The resulting rosin-fatty acid vinylic polymer grinding resin compositions have a weight average molecular weight in the range of about 4,000 to about 12,000; with the preferred molecular weights being in the range of about 5,000 to about 11,000.
These rosin-fatty acid vinylic polymer compositions have characteristics which differ from the traditional melt blends of flake acrylic fatty acid rosin. For example, the low molecular weights of the rosin-fatty acid vinylic polymers enable the polymers to be neutralized at high solid levels while maintaining low viscosities. The low molecular weight coupled with the polymer's high levels of functional carboxyl units permits the production of support resins (i.e., dispersions of the vinylic polymer in aqueous base) which contain high amounts of functional polymer components while maintaining targeted viscosity levels for ink formulation purposes. The rosin-fatty acid vinylic polymer support resin compositions a
Adams Stanley C.
Shah Rajnikant
McDaniel Terry B.
Reece IV Daniel B.
Schmalz Richard L.
Westvaco Corporation
Wu David W.
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