Compositions: coating or plastic – Coating or plastic compositions – Silicon containing other than solely as silicon dioxide or...
Reexamination Certificate
1998-02-17
2001-03-20
Moore, Margaret G. (Department: 1712)
Compositions: coating or plastic
Coating or plastic compositions
Silicon containing other than solely as silicon dioxide or...
C528S026000, C525S102000, C524S588000, C524S869000, C524S405000, C524S417000
Reexamination Certificate
active
06203607
ABSTRACT:
BACKGROUND OF THE INVENTION
The current invention relates to a coating composition comprising polyacetoacetate and crosslinker for said polyacetoacetate.
Coating compositions of this type are generally known from, for example, U.S. Pat. No. 3,668,183, “Polyenamine Coatings: I. Formulation of Coatings and Determination of Film Properties”, K. L. Hoy and C. H. Carder,
Journal of Paint Technology,
Vol. 46, No. 591, April 1974, pages 70-75, and “Polyenamine Coatings: II. Chemical Methods of Improving Film Properties”, C. H. Carder and H. O. Colomb, Jr.,
Journal of Paint Technology,
Vol. 46, No. 591, April 1974, pages 76-78, referred to respectively as “Polyenamine Coatings I” and “Polyenamine Coatings II”. Such coating compositions, when properly formulated and applied to a substrate, form a coating having highly desirable properties, such as hardness, flexibility and toughness. There is, however, a continuing difficulty in that such coatings frequently do not adequately adhere to the substrate on which they are applied.
U.S. Pat. No. 3,668,183 generally discloses the production of polyenamine resins by the reaction of polyacetoacetates with blocked polyamines. Also disclosed there is the possible use of a silicone component in the polyacetoacetate end cap to improve acid resistance.
WO-A-94/21738 discloses a crosslinkable liquid carrier-based coating composition comprising organic polymer(s) having acetoacetyl group functionality, a polyamine compound(s) having at least two acetoacetyl-reactive amino groups per molecule and a non-polymeric monoacetoacetyl compound(s) selected from a specific group of such compounds. The ratio of acetoacetyl groups of the acetoacetyl functional polymer(s) to the number of acetoacetyl-reactive amino groups of the polyamine compound(s) is between 0.5/1 and 2/1. The particularly preferred ratio is at or very near to 1.
This invention provides a coating composition of the above-described type which, when cured, has a highly improved adhesion to the substrate. Other advantages include highly desirable cure-to-pot life ratio and corrosion-resistance properties. Further, it is possible to formulate the current compositions with low volatile organic content. Still further, the coating compositions herein disclosed are especially useful in the production of a multi-layer coating system, in particular for metal substrates, more particularly aluminum substrates, and more particularly, for aluminium for aircraft. In multi-layer coating systems, the coating compositions of the current invention are especially useful as the primer, and, in particular, primers which are free, or substantially free, of chromate pigment. As used herein, “primer” means any coating layer in direct contact with the substrate, after optional cleaning, conversion coating and/or other pre-treatment of the substrate.
SUMMARY OF THE INVENTION
The coating composition of the instant invention comprises a polyacetoacetate having acetoacetate groups, a crosslinker for said polyacetoacetate, and an organosilane.
The coating composition of the invention is further characterized in that the organosilane may be of the following general formula
wherein
Z is an amino group, an amino-containing group, an epoxy group, an epoxy-containing group, a mercapto group, a mercapto-containing group, a vinyl group, a vinyl-containing group, an isocyanate group, an isocyanate-containing group, an ureido group, an ureido-containing group, an imidazole group or an imidazole-containing group,
R is an aliphatic, alicylic or aromatic group,
R′ is an alkoxy group or alkoxyalkoxy groups,
R″ is an alkyl group having 1 to about 8 carbon atoms,
x is 0 to about 20,
a is 0 to 3, preferably 0 to 2,
b is 1 to 4, preferably 1 to 3,
c is 0 to 3, and preferably 0 to 2, and
the sum of a+b+c is 4.
Preferred organosilanes are aminosilanes, epoxysilanes, mercaptosilanes, vinylsilanes, ureidosilanes, imidazolsilanes and isocyanatosilanes.
DETAILED SUMMARY OF THE INVENTION
Polyacetoacetates are acetoacetate-functional compounds having at least two acetatoacetate groups. Polyacetoacetates are well known in the art, for example as demonstrated in the already mentioned U.S. Pat. No. 3,668,183, U.S. Pat. No. 5,021,537, “Polyenamine Coatings I” and “Polyenamine Coatings II”. They can be described as the partial or complete acetoacetylation product of a monomeric polyalcohol having at least two free hydroxyl groups or an oligomeric or polymeric condensation derivative of such polyalcohols. The production of polyacetoacetates, “acetoacetylation”, may be accomplished by various reaction schemes. Some examples are transesterification of alkyl acetoacetates, such as methyl, ethyl or t-butyl acetoacetate with polyols or the reaction of polyol or polythiol with diketene, or the diketene-acetone adduct 2,2,6-trimethyl-1,3-dioxin-4H-one. Such compounds and synthesis mechanisms are well known in the art (see for example U.S. Pat. No. 3,668,183 and “The Acetoacetyl Functionality: A New Approach to Thermoset Coatings”, R. J. Clemens, et al.,
Proceedings: XVI
th
International Conference in Organic Coatings Science and Technology, Jul. 9-13, 1990, Athens, Greece, page 127 et seq., and “Comparison of Methods for the Preparation of Acetoacetylated Coating Resins”, J. S. Witzeman et al.,
Journal of Coating Technology
62, No. 789, 101 (1990)) and need not be further detailed here.
Preferably, polyacetoacetates used in the current invention are partial or complete acetoacetylation products of (1) monomeric polyalcohols having 2 to 6 hydroxyl groups, (2) partial esters of polyalcohols with monocarboxylic acids (the carboxylic acids having 2 to 22 and preferably 5 to 18 carbon atoms), the partial esters having at least 2 unreacted hydroxyl groups, (3) polymeric condensates having at least 2 hydroxyl groups, suitable polymeric condensates being, for non-limiting example, polyesters, polyethers and/or polyurethanes (see, for example,
The Chemistry of Organic Film Formers,
D. H. Solomon, Robert E. Krieger Publishing Co., 1977) and (4) addition polymers containing at least two (2) hydroxyl groups.
Some examples of monomeric polyalcohols having 2 to 6 hydroxyl groups which can be conveniently converted into polyacetoacetates include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-butyl-propanediol, 2-methylpropanediol, 3-methyl-1,5-pentanediol, di-ethylene glycol, triethylene glycol, 1,4-cyclohexyldimethanol, dipropylene glycol, trimethylolethane, trimethylolpropane, glycerol, di-trimethylolpropane, pentaerythritol and the like.
Suitable partial esters of polyalcohols with monocarboxylic acids containing 2 to 22, preferably 5 to 18 carbon atoms, the partial esters having at least 2 unreacted hydroxyl groups, include for example the reaction product of a triol, e.g. trimethylolpropane, with a monocarboxylic acid in a, for example, 1:1 molar ratio. Other suitable partial esters are the reaction products of a tetrol e.g. pentaerythritol, with a monocarboxylic acid in, for example, 1:1 or 1:2 molar ratio. Useful monocarboxylic acids are: acetic acid, hexanoic acid, 2-ethylhexanoic acid, nonaoic acid, 3,5,5-trimethylhexanoic acid, benzoic acid, oleic acid, linoleic acid, dehydrated castor oil fatty acid, and the like. It is well known that esterification of polyalcohols with monocarboxylic acids in a stoichiometric excess of the hydroxyl component generally yield a mixture of products with different degrees of esterification and having different hydroxyl functionalities. In addition to single alcohols and acids, mixtures of one or both reactants may also be used.
Usually monomeric polyalcohols like trimethylolpropane, di-trimethylolpropane, pentaerythritol and other alcohols with 3 or more hydroxyl groups are partially esterified, however, if desired, polymeric preformed polyalcohols such as polyester-, polyether- and polyurethane polyols, and addition polymers, all containing 2 or more hydroxyl groups can be partially esterified with monocarboxylic acids
Schoonderwoerd Nicolaas Antonius Maria
Vandevoorde Paul Marie
Akzo Nobel N.V.
McGillycuddy Joan M.
Moore Margaret G.
Morris Louis A.
LandOfFree
Coating composition comprising polyacetoacetate, crosslinker... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating composition comprising polyacetoacetate, crosslinker..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating composition comprising polyacetoacetate, crosslinker... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2448551