Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2001-12-11
2004-05-11
Yoon, Tae H. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C523S160000, C524S607000, C525S054440, C525S183000, C528S345000
Reexamination Certificate
active
06734280
ABSTRACT:
FIELD OF INVENTION
This invention concerns novel rosin-fatty acid vinylic polyamide polymer resin compositions and the process for preparing them. More particularly, the invention concerns novel rosin-fatty acid vinylic polyamide graft polymer compositions that exhibit properties that make them useful as resins for improving the adhesion of water-based inks and coatings to plastic substrates.
BACKGROUND OF THE INVENTION
Gravure and flexographic printing methods are widely used in the packaging industry for applying decorative and informative graphics to various substrates, particularly paper, board, metal foils, and plastic films. The inks traditionally used in these printing processes typically consist of a pigment dispersed in a liquid vehicle, which itself comprises a resin dissolved in an organic solvent.
In recent years, much of the packaging printing on paper and board substrates has switched from these solvent-based inks to more environmentally friendly water-based ones, where the vehicle comprises an aqueous solution or dispersion of resin. Conversion of inks for plastic films to aqueous vehicles has, however, been retarded by the poor adhesion of most water-based resins to these substrates.
One of the most widely used classes of resins in solvent-based inks for plastic films is polyamides, particularly dimer acid-based polyamides, such as the VERSAMID resins manufactured by Henkel Corporation. These polyamides provide excellent adhesion to such films as corona-treated polyethylene and polypropylene. Therefore, attempts have been made in the past to modify polyamide resins to make them water-dispersible, with the expectation that such modified polyamides would provide aqueous inks with good adhesion to plastic films. For example, U.S. Pat. Nos. 4,870,139 and 5,026,755 teach the graft polymerization of acrylic monomers onto polyamides in high solids alcohol solutions. The resulting solutions of graft copolymers are then mixed with water and amines to form aqueous ink vehicles. A problem with this method is that a considerable amount of alcohol remains in the finished ink. It would be most desirable from an environmental point of view to have no solvent of any kind in the finished ink.
U.S. Pat. No. 5,183,847 teaches the production of graft copolymers by fusing together at high temperature a maleated rosin, a polyamide resin, and an acrylic resin. This method produces an amide-containing resin that can be readily dispersed in aqueous ammonia without the need for any organic cosolvent. However, the method is relatively expensive and time-consuming, being what is known in the art as a “three-pot” procedure. That is, the method requires the separate manufacture of both the acrylic and the polyamide resin, which are subsequently reacted with the maleated rosin to produce the graft copolymers.
Therefore, an object of this invention is to solve these major problems by disclosing a method of producing rosin-fatty acid vinylic polyamide graft polymer compositions that exhibit properties that make them useful as resins in water-based ink, overprint, and other coating formulations.
Another object of this invention is to disclose rosin-fatty acid vinylic polyamide graft polymer resin compositions.
SUMMARY OF THE INVENTION
The objects of this invention are met via the process of: (a) forming a vinylic resin in the presence of a mixture of unsaturated fatty acid and rosin, (b) adducting the rosin fatty acid vinylic mixture in the same reactor, and (c) adding a pre-formed polyamide resin and fusing it with the adducted rosin-fatty acid vinylic resin mixture to produce the rosin-fatty acid vinylic polyamide graft polymer compositions which are useful as resins in water-based ink, overprint varnishes, and other coating applications.
The process is a relatively economical “two-pot” procedure where only the polyamide has to be pre-manufactured. Moreover, the process employs rosin and fatty acid to act as solvents in the polymerization reaction of the acrylic monomers. As this method does not require the use of organic 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 resin composition. Finally, the incorporation by grafting of fatty acid residues onto the resulting resin compositions serves to enhance the adhesion of the resins to plastic substrates.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The rosin-fatty acid vinylic polyamide polymer resin compositions are the products of 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 fatty acid rosin mixture of unsaturated fatty acid, and
(b) about 10.0% to about 90.0% by total weight of the fatty acid rosin 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 monomer mixture of a member selected from the group consisting of acrylic acid, methacrylic acid, and combinations thereof,
(b) about 55.0% to about 85.0% by total weight of the monomer mixture of non-carboxylic acid containing vinylic monomer,
(c) about 0.5% to about 5.0% by total weight of the monomer mixture of polymerization initiator, and
(d) up to about 4.0% by total weight of the monomer mixture of chain transfer agent, at a temperature in the range of about 135° C. to about 175° C. to produce a rosin-fatty acid vinylic polymer having a weight average molecular weight in the range of about 4,000 to about 12,000;
(B) reacting in an “ene” or Diels-Alder adduction reaction:
(1) about 88.0% to about 99.5% by total weight of the reactants of rosin-fatty acid vinylic polymer, and
(2) about 0.5% to about 12.0% by total weight of the reactants of a member selected from the group consisting of &agr;,&bgr;-unsaturated carboxylic acids, &agr;,&bgr;-unsaturated carboxylic anhydrides, and combinations thereof at a temperature in the range of about 170° C. to about 240° C. to produce an adducted rosin fatty acid vinylic polymer;
(C) reacting in a condensation polymerization reaction:
(1) about 65.0% to about 95.0% by total weight of the reactants of the adducted rosin fatty acid vinylic polymer, and
(2) about 5.0% to about 35.0% by total weight of the reactants of dimer acid-based polyamide resin at a temperature in the range of about 200° C. to about 280° C.;
to produce the rosin-fatty acid vinylic polyamide polymer resin compositions.
Preferred rosin-fatty acid vinylic polyamide polymer resin compositions are the products of 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 20.0% to about 50.0% by total weight of the fatty acid rosin mixture of unsaturated fatty acid, and
(b) about 50.0% to about 80.0% by total weight of the fatty acid rosin 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 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, and combinations thereof,
(b) about 60.0% to about 70.0% by total weight of the monomer mixture of non-carboxylic acid containing vinylic monomer,
(c) about 1.0% to about 3.0% by total weight of the monomer mixture of polymerization initiator, and
(d) about 0.5% to about 2.0% by total weight of the monomer
McDaniel Terry B.
MeadWestvaco Corporation
Reece IV Daniel B.
Yoon Tae H.
LandOfFree
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