Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1995-04-24
2003-06-10
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C524S514000, C524S603000, C524S609000, C525S291000
Reexamination Certificate
active
06576717
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to novel water-dispersible acrylic-modified polyesters, the method of their preparation, and coatings prepared therefrom.
BACKGROUND OF THE INVENTION
Regulations to limit the amount of volatile organic compounds (VOC) of industrial coatings have encouraged research and development projects directed at inventing new waterborne systems such as paints. Polyester and acrylic resins are the two most common polymers used for these types of coating systems. These two polymers are synthesized by different types of polymerization mechanisms, and their chemical structures are basically different. While the ester linkages of polyesters lead to flexible coatings with good impact resistance, they are also prone to hydrolysis which results in poorer enamel stability and coating weatherability. On the other hand, the carbon-carbon bonds formed in acrylic backbones provide coatings with good weatherability, but they also attribute to the coating's brittleness and poor impact resistance.
Which of these two types of resins are used depends upon the desired properties of various coating applications. Nevertheless, it is often desirable to have coatings with good impact resistance as well as weatherability, such as those used for automotive finishes. As a result of this desired mix of properties, the coating industry has attempted to combine and take advantage of these two technologies. One technique to achieve this would be to make resin or solution blends of polyesters and acrylic. This method would generally be good for solvent-based coatings, but would encounter compatibility problems in waterborne coatings since they would phase-separate and form hazy films.
The application of some types of acrylic-modified resins in coatings and related products has been disclosed. JP 51119043 discloses an organic solvent-based high-solids coating composition containing an acrylic resin modified by a polymerizable unsaturated oil-free alkyd resin. Kobayashi (Shikizai Kyokaishi, 58(5), 249-56, 1985) studies the effects of acrylic resins modified with polyesters on the dispersion stability of carbon black in non-aqueous solutions. The resins are prepared by copolymerization of polyesters having maleic anhydride units with vinyl monomers. JP 56139562 discloses thermosetting resin powders containing a polyester-modified vinyl polymer, a phosphoric acid group-containing polymer, and a blocked polyisocyanate which form stable aqueous dispersions when neutralized with triethylamine. U.S. Pat. No. 4,735,995 discloses water-dispersible air-drying acrylic-modified polyesters having acid values greater than about 25.
European Patent Application 499099 discloses receptor sheets for thermal-transfer printing containing graft polymers. JP 02310048 discloses a hydrophilic polyester grafted with vinyl monomers. U.S. Pat. No. 5,156,651 discloses a graft sulfonated polyester for sizing textile threads and fibers.
The above modified resins have not solved the problems and have not produced a resin that provides a flexible coating with good impact resistance, good hardness, and good weatherability.
Water-dispersible polyesters containing sulfomonomers are known. U.S. Pat. No. 4,340,519 discloses the composition of certain crystalline and non-crystalline polyesters copolymerized with a metal sulfonate group-containing aromatic acid and up to 10 mol percent (based on the total polyol content) of a polyvalent polyol selected from trimethylolpropane, trimethylolethane, glycerine, and pentaerythritol. Also, U.S. Pat. No. 4,525,524 discloses liquid systems comprised of polyesters containing certain metal sulfonates and, optionally, up to 3 percent of a branching agent based upon the total diol component. U.S. Pat. No. 3,563,942 discloses linear solvent-soluble copolyester compositions that can be dispersed in water. Water dispersibility is gained by the addition to the copolyester of a small amount (1-2 mol percent) of the metal salt of sulfonated aromatic compounds.
U.S. Pat. Nos. 4,483,963, 4,622,381 and 4,818,569 and JP 62045731, 62021816, and 61289116 disclose high molecular weight, linear polymers end-capped with sulfobenzoyl groups.
Many patents disclose methods to obtain water-dissipatable polyesters by neutralizing residual or unreacted carboxylic acid groups on the polymer with ammonia or various organic amines. U.S. Pat. No. 3,666,698 utilizes this method as well as phenylindandicarboxylic acid to modify coating performance. U.S. Pat. No. 3,699,066 shows the benefits of certain hydroxy-functional amines for neutralization. U.S. Pat. No. 3,549,577 utilizes the amino resin crosslinker as the neutralizing agent then adjusts the pH to prepare an alkaline water-reduced system. In these patents as well as in U.S. Pat. Nos. 3,494,882, 3,434,987, U.K. 1,117,126, and U.S. Pat. No. 3,345,313 carboxylic acid functionality is completely neutralized with excess base yielding an alkaline paint vehicle.
U.S. Pat. Nos. 4,910,292, 4,973,656 and 4,990,593, the disclosures of which are incorporated herein in their entirety by reference, disclose an improved water-borne polyester resin and coatings specifically containing 5-(sodiosulfo)-isophthalic acid (5-SSIPA or SIP). The clear coating prepared from this resin exhibits good properties of gloss, hardness, flexibility, and solvent resistance. However, as with other polyester resins, coatings prepared from these resins do not have adequate hydrolytic stability and weatherability.
In light of the above, it would be very desirable to produce a resin that forms a flexible coating with good impact resistance, good hardness, good hydrolytic stability, and good weatherability.
SUMMARY OF THE INVENTION
The present invention is directed to a water-dispersible crosslinkable resin composition that comprises the acrylic-modified polyester made of the moieties of bulk or solution addition-copolymerization products:
(I) about 20 to 90 weight percent of a polyester made of the moieties of polycondensation products:
(a) at least one difunctional dicarboxylic acid which is not a sulfomonomer;
(b) about 1 to 20 mol percent of at least one sulfomonomer containing at least one metallic sulfonate group or nitrogen-containing non-metallic sulfonate group attached to an aromatic or cycloaliphatic nucleus and at least one functional group selected from the group consisting of hydroxy, carboxyl, and amino;
(c) at least one difunctional reactant selected from a glycol or a mixture of a glycol and diamine having two —NRH groups, the glycol containing two —C(R
1
)
2
—OH groups wherein R in the reactant is hydrogen or an alkyl group of 1 to 6 carbon atoms, and R
1
in the reactant is a hydrogen atom, an alkyl of 1 to 5 carbon atoms, or an aryl group of 6 to 10 carbon atoms;
(d) about 1 to 8 mol percent of at least one ethylenically unsaturated monomer which contains at least one carboxyl, hydroxyl, anhydride, or epoxy group;
(e) about 0 to 40 mol percent of a difunctional reactant selected from hydroxycarboxylic acids having one —C(R)
2
—OH group, aminocarboxylic acids having one —NRH group, amino-alcohols having one —C(R)
2
—OH group and one —NRH group, or mixtures of said difunctional reactants wherein R in the reactant is hydrogen or an alkyl group of 1 to 6 carbon atoms; and
(f) about 0 to 40 mol percent of a multifunctional reactant containing at least three functional groups selected from hydroxyl, carboxyl, and mixtures thereof wherein at least a portion of the multifunctional reactant contains at least three hydroxyl groups,
wherein all stated mol percentages are based on the total of all acid, hydroxyl and amino group containing reactants being equal to 200 mol percent, and wherein the polymer contains proportions of acid-group containing reactants (100 mol percent acid) to hydroxy- and amino-group containing reactants (100 mol percent base) such that the value of EQ (base) divided by EQ (acid) is between about 0.5 and 2; and
(II) about 10 to 80 weight percent of at least one ethylenically unsaturated vinyl monomer.
The present invention is also directe
Carrier Michael
Dawson Robert
Eastman Chemical Company
Graves Bernard
LandOfFree
Water-dispersible acrylic-modified polyester resins used in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Water-dispersible acrylic-modified polyester resins used in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Water-dispersible acrylic-modified polyester resins used in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151034