Stock material or miscellaneous articles – Composite – Of silicon containing
Reexamination Certificate
2001-06-20
2003-08-12
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Composite
Of silicon containing
C428S413000, C428S480000, C428S473500, C428S474400, C428S500000, C106S287100, C106S287130, C106S287160, C106S287250, C106S287300, C524S189000, C524S261000, C524S265000, C524S269000, C528S028000, C528S034000, C528S119000, C528S288000, C528S367000, C528S422000
Reexamination Certificate
active
06605359
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to novel coating compositions prepared from a reactive polymer, a hydrazide compound and a silane compound. The coating compositions, which can be formaldehyde-free and isocyanate-free, cure to provide an interpenetrating network (IPN) coating having excellent properties.
Paints can be considered as falling into two general categories, namely, water-based paints and solvent-based paints. Which category of paint is suitable for a given application depends on the conditions to be experienced by the paint. Conventional water-based paints have generally been considered inferior to solvent-based paints with respect to weather resistance, solvent resistance and adhesion. Recently, however, the use of solvent-based paints has become environmentally disfavored, with an emphasis being placed on achieving acceptable results with paints having a relatively low volatile organic content (“VOC”). Specifically, efforts have been made to provide paints or coatings which are isocyanate-free and formaldehyde-free yet which exhibit acceptable physical characteristics.
It is therefore an object of the present invention to provide a coating composition which can be isocyanate-free and formaldehyde-free, yet exhibit good adhesion, durability, chemical resistance, water resistance and print resistance. This desired combination of properties has now been achieved by the novel coating compositions described herein.
SUMMARY OF THE INVENTION
The novel coating compositions described herein include a polymer, a hydrazide and a silane. The polymer has at least one reactive functional group. Non-limiting examples of the silane include silanes and polysilanes. Optionally, the coating composition includes a pigment. Coatings made from such compositions are also described. Methods of preparing a coating by applying the coating composition to a substrate and curing to form a film are also described herein. The invention also relates to a substrate coated with the novel coating composition.
The preferred coating compositions in accordance with this disclosure are formaldehyde-free and isocyanate-free, can be air cured and provide coatings that exhibit improved adhesion to the substrate, improved print and block resistance and improved solvent and water resistance.
DETAILED DESCRIPTION OF THE INVENTION
Non limiting examples of the novel coating compositions in accordance with this disclosure include: (1) (a) a polymer, (b) a hydrazide and (c) a silane; and (2) (a) a polymer having at least one reactive functional group, the polymer also having a hydrazide group attached thereto, and (b) a silane.
Polymers useful in forming the coating compositions include, for example, acrylic polymers, modified acrylic polymers, polyepoxides, polyesters, polycarbonates, polyurethanes, polyamides, polyimides, polysiloxanes, polycarbamates and mixtures thereof. The molecular weight of the polymer is not critical. The polymer will generally have a molecular weight of 2,000 to 2,000,000 and preferably from 100,000 to 1,000,000.The polymer includes reactive functional groups. The functional groups can provide a site for attachment of the hydrazide-containing compound and also can provide a site for cross-linking by the silane compound as described in detail below. Suitable reactive functional groups include, for example, carboxyl, hydroxyl, epoxy, amino, alkylamino, multi-functional amine, amido, silane, silanol and keto groups or combinations thereof. The degree of substitution of the reactive functional groups is not critical, but rather can be adjusted to provide a coating having desired characteristics. Thus, for example, where carboxyl groups are present on the polymer, acid numbers as low as about 20 should provide adequate cross-linking to form a coating. However, if a coating which can withstand 200 MEK rubs is desired, an acid number in the range of about 40 to about 80 should be used. The polymer may be self-crosslinking or U.V. curable. It is within the purview of one skilled in the art to prepare suitable polymers containing reactive functional groups. Suitable polymers are commercially available from a variety of suppliers.
Where acrylic polymers are utilized, such polymers can be prepared from monomers such as acrylic acid and methacrylic acid, alkyl and cycloalkyl acrylates and methacrylates having 1 to 18, preferably 4 to 13, carbon atoms in the alkyl or cycloalkyl moiety, or mixtures of such monomers, by way of non-limiting example. Non-limiting examples of these include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, n-butyl methacrylate, 2-ethylhexyl acrylate, cyclohexyl methacrylate, and 2-ethylhexyl methacrylate.
The reactive functionality on the acrylic polymer may be incorporated by reacting functional monomers, such as those having carboxyl, hydroxyl, epoxy, amino, keto, silane, silanol, and alkylamino functional groups, by way of non-limiting example. Non-limiting examples of carboxyl containing monomers include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-acryloxymethoxy-O-phthalic acid, 2-acryloxy-1-methylethoxy-O-hexahydrophthalic acid. Hydroxy functional monomers include 2-hydroxylethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxy butyl acrylate, hydroxybutyl methacrylate, allyl alcohol, and methallyl alcohol. A non-limiting example of an epoxy functional monomer includes glycidyl methacrylate. Non-limiting examples of alkylamino acrylates and methacrylates include aminomethyl, aminopropyl, aminobutyl and aminohexyl acrylates and methacrylates, dimethylaminoethyl acrylate, and dimethylaminoethyl methacrylate. Other suitable monomers include N-alkoxymethylacrylamide, and N-(butoxymethyl)acrylamide. Other ethylenically unsaturated monomers such as vinyl, styrene, &agr;-methyl styrene, vinyl toluene, t-butyl styrene may also be included to provide the desired physical characteristics. A non-limiting example of a keto containing monomer includes diacetone acrylamide. Non-limiting examples of silane containing monomers, include alkoxysilane functional monomers, such as gamma-methylacryloxy propyl-trimethoxy silane, gamma-methylacryloxypropyl-triethoxy silane, gamma-methylacryloxypropyl-triisopropoxy silane, etc. A silanol functionality is achieved upon hydrolysis of a silane functional monomer, such as those identified herein, by way of non-limiting example. Particularly useful polymers are carboxylated styrene acrylate polymers.
Modified acrylics can also be used as the acrylic polymer. Non-limiting examples of these include polyester-modified acrylics or polyurethane-modified acrylics, as are well known in the art. An example of one preferred polyester-modified acrylic is an acrylic polymer modified with &dgr;-caprolactone. Such a polyester modified acrylic is described in U.S. Pat. No. 4,546,046 to Etxell et al. Polyurethane modified acrylics are well known in the art. An example is set forth in U.S. Pat. No. 4,584,354, the disclosure of which is hereby incorporated by reference.
Polyesters having hydroxyl groups, acid groups, or amino groups as reactive functional groups can also be used as the polymer in the present compositions. Such polyesters are well-known in the art, and may, for example, be prepared by the polyesterification of organic polycarboxylic acids (e.g., phthalic acid, hexahydrophthalic acid, adipic acid, maleic acid) or their anhydrides with organic polyols containing primary or secondary hydroxyl groups.
Polyurethanes useful as the polymer in the present compositions can be prepared, for example, by reacting polyisocyanate and polyol with an OH:NCO equivalent ratio of greater than 1:1, to obtain polyurethanes with terminal hydroxyl functionality. In this case, capping of the isocyanate occurs simultaneously with the synthesis of the polyurethane resin. Alternatively, polyurethane may be formed by reacting polyisocyanate and polyol with an OH:NCO ratio of less than 1:1. In this
Robinson Gregory Frantz
Shemancik Robin Carol
Speight Robert Dale
Wong Philip Titsum
Znidersic Kenneth M.
Akzo Nobel N.V.
Dawson Robert
Parker Lainie E.
Robertson Jeffrey B.
LandOfFree
Coating compositions and coatings formed therefrom 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 compositions and coatings formed therefrom, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating compositions and coatings formed therefrom will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3082205