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Coating compositions, their preparation, and coated articles made therefromRelated Patent Categories: Synthetic Resins Or Natural Rubbers -- Part Of The Class 520 Series, Natural Rubber Compositions Having Nonreactive Materials (dnrm) Other Than: Carbon, Silicon Dioxide, Glass Titanium Dioxide, Water, Hydrocarbon, Halohydrocarbon, Ethylenically Unsaturated Reactant Admixed With A Preformed Reaction Product Derived From: (a) At Least One Polycarboxylic Acid, Ester, Or Anhydride; (b) At Least One Polyhydroxy Compound; And (c) At Least One Fatty Acid Glycerol Ester, Or A Fatty Acid Or Salt Derived From A Naturally Occurring Glyceride, Tall Oil, Or A Tall Oil Fatty Acid, At Least One Solid Polymer Derived From Ethylenic Reactants Only, Polymer Derived From Ethylenic Reactants Only Mixed With Ethylenic ReactantCoating compositions, their preparation, and coated articles made therefrom description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070191549, Coating compositions, their preparation, and coated articles made therefrom. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] This invention relates to coating compositions comprising polyarylates, the methods of preparing polyarylates and coated articles prepared using the coating compositions of the present invention. [0002] Modern commerce and technology frequently employ organic coatings to shield various sensitive substrates from the harmful effects of the environment. Many such coatings are limited by long-term color instability, a limitation which is evidenced by a yellowing of the organic coating over time. Yellowing due to a coating's constituent polymeric components may be caused by the action of ultraviolet (UV) radiation. Another frequently encountered problem with organic coatings based on polymeric materials is poor resistance of the coating to chemicals and solvents after its application. Coatings which are tough, chemically resistant and "weatherable" (i.e. resistant to the effects of sunlight and other environmental conditions) are highly prized and diligently sought after. [0003] Generally it has been observed that there is a tradeoff between weatherability and toughness in the performance of the commercial coating compositions known in the art. One solution to this problem has been the combination of extremely tough epoxies with polyesters to provide coatings with improved weatherability. Similarly acrylates, which are known to exhibit good weatherabiliy, but poor toughness, have been combined with polyester resins to improve their toughness. Compositions containing polyoxymethylene resins and various additives to improve toughness or impact strength are also known. [0004] Certain types of polyarylates, known for their good weatherability and chemical resistance, have been found in the instant invention to be useful in the preparation of novel coating compositions having excellent scratch resistance and other properties. Up to the present, hydroxy-terminated polyarylates units have been prepared via interfacial polymerization methods. Despite recent strides in interfacial polyarylate synthesis, such interfacial methods are limited by an inability to control the molecular weight of the growing polyarylate chains. Typically the interfacial polymerization method provides polyarylates with high molecular weights, materials which may not be suitable for certain coating applications. [0005] It remains of interest therefore, to develop coating compositions that demonstrate scratch resistance, toughness, chemical resistance and weatherability, suitable for application over various types of substrates in a wide variety of applications. There is also a need for synthetic methodology to prepare polymers comprising resorcinol chain members, having controlled molecular weight. The instant invention addresses these and other challenges and provides new and highly efficient solutions to them. BRIEF SUMMARY OF THE INVENTION [0006] In one aspect, the present invention provides a coating composition comprising components A, B and optionally C: [0007] (i) component A comprising at least one polyarylate, said polyarylate comprising structural units having formula I wherein R.sup.1 is independently at each occurrence a C.sub.1-C.sub.12 alkyl radical and n is 0-3, said polyarylate further comprising phenolic hydroxy groups; [0008] (ii) component B comprising at least one "organic species" comprising one or more functional groups, said functional groups being chemically reactive with the phenolic hydroxy groups of the polyarylate of component A; and optionally [0009] (iii) component C one or more catalysts which promote chemical reaction between the polyarylate hydroxyl groups of component A and the "organic species" of component B. [0010] In another aspect, the present invention provides powder coatings comprising at least one polyarylate, said polyarylate comprising structural units having formula I. In yet another aspect, the present invention provides a method for preparing polyarylates comprising structural units having formula I. In still another aspect, the present invention provides a coated article comprising a coating layer prepared from the coating composition of the invention. DETAILED DESCRIPTION OF THE INVENTION [0011] The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. In the following specification and the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings: [0012] The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. [0013] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. [0014] As used herein the term "aliphatic radical" refers to a radical having a valence of at least one and consisting of a linear or branched array of atoms which is not cyclic. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of aliphatic radicals include methyl, methylene, ethyl, ethylene, hexyl, hexamethylene, methoxy, ethoxy, thiomethyl, thioethyl, and the like. [0015] As used herein the term "cycloaliphatic radical" refers to a radical having a valance of at least one and comprising an array of atoms which is cyclic but which is not aromatic, and which does not further comprise an aromatic ring. The array may include heteroatoms such as nitrogen, sulfur and oxygen or may be composed exclusively of carbon and hydrogen. Examples of cycloaliphatic radicals include cyclopropyl, cyclopentyl cyclohexyl, 2-cyclohexylethy-1-yl, tetrahydrofuranyl and the like. [0016] As used herein the term "aromatic radical" refers to a radical having a valence of at least one and comprising at least one aromatic ring. Examples of aromatic radicals include phenyl, pyridyl, furanyl, thienyl, naphthyl, phenylene, and biphenyl. The term includes groups containing both aromatic and aliphatic components, for example a benzyl group, a phenethyl group or a naphthylmethyl group. The term also includes groups comprising both aromatic and cycloaliphatic groups for example 4-cyclopropylphenyl and 1,2,3,4-tetrahydronaphthalen-1-yl. [0017] As noted, the present invention provides a coating composition comprising components A, B and optionally C, wherein component A comprises at least one hydroxy-terminated polyarylate having structural units of formula I, component B is an organic species which can react with the hydroxy terminal groups of component A, and component C is a catalyst or mixture of catalysts. [0018] Typically component A comprises a hydroxy-terminated polyarylate comprising arylate polyester chain members. Said chain members comprise at least one dihydroxy-substituted aromatic hydrocarbon moiety in combination with at least one aromatic dicarboxylic acid moiety. In one particular embodiment the dihydroxy-substituted aromatic hydrocarbon moiety is derived from a 1,3-dihydroxybenzene moiety, illustrated in the structural moiety of formula (II), commonly referred to throughout this specification as resorcinol or a resorcinol moiety. In formula (II), R.sup.2 is at least one of C.sub.1-12 alkyl or halogen, and n is 0-3. Resorcinol or resorcinol moiety as used within the context of the present invention should be understood to include both unsubstituted 1,3-dihydroxybenzene and substituted 1,3-dihydroxybenzenes unless explicitly stated otherwise. The concentration of component A of formula I, in the coating composition is in the range of about 1 to about 99 percent by weight of the coating composition. In one embodiment, the concentration of structural units of formula II in component A is in a range between about 0.01 and about 50 percent by weight of the total weight of the coating composition. In another embodiment, the concentration of structural units of formula II in component A is in a range between about 0.1 and about 20 percent by weight of the total weight of the coating composition. In yet another embodiment the concentration of structural units II in component A is in a range between about 0.1 and about 10 percent by weight of the total weight of the coating composition. [0019] Suitable dicarboxylic acid residues include aromatic dicarboxylic acid residues derived from monocyclic moieties, including isophthalic acid, terephthalic acid, or mixtures of isophthalic and terephthalic acids, or from polycyclic moieties. In various embodiments, the aromatic dicarboxylic acid residues are derived from mixtures of isophthalic and terephthalic acids as typically illustrated in the structural moiety of formula (III). [0020] Therefore, in one particular embodiment, the present invention provides coating compositions comprising hydroxy-terminated polyarylates, said polyarylates comprising resorcinol-arylate polyester chain members as typically illustrated in the structural moiety of formula (I) wherein R.sup.1 and n are as previously defined. [0021] The hydroxy-terminated polyarylates present in component A may be prepared by a variety of methods which include the interfacial reaction of a dihydroxy-substituted aromatic hydrocarbon with an aromatic diacid chloride. Methods for carrying out for such interfacial reactions to produce hydroxy-terminated polyarylates are disclosed in copending U.S. application Ser. No. 120582 and in U.S. Pat. Nos. 6,306,507 and 6,294,647. Through careful control of the reaction parameters during the interfacial preparation of the hydroxy-terminated polyarylates, poor thermal stability which is sometimes observed in such polyarylates may be overcome. [0022] Typically, control of the molecular weight of the hydroxy-terminated polyarylates has proven difficult to achieve. In the absence of a chain-stopper, the molecular weight of the hydroxy-terminated polyarylate produced interfacially is relatively insensitive to stoichiometric control. This is particularly true when the dihydroxy-substituted aromatic compound and its salts are highly insoluble in the solvent forming the organic phase of the interfacial reaction mixture. Earlier attempts to control polyarylate molecular weight led to the discovery that by increasing the molar ratio of the dihydroxy-substituted aromatic compound to the diacid chloride employed, and by decreasing the amount of water present in the interfacial reaction of the dihydroxy-substituted aromatic compound with the diacid chloride, enhanced control of the molecular weight of the hydroxy-terminated polyarylate could be achieved without the use of an end capping agent. A failure to control the molecular weight of the hydroxy-terminated polyarylate limits the utility of the hydroxy-terminated polyarylate in the preparation of coating formulations due to the higher glass transition temperatures (Tg) and lower concentration of hydroxyl end groups of the higher molecular weight polyarylates relative to oligomeric polyarylates. [0023] It has been discovered within the context of the present invention that excellent control over the molecular weight of the hydroxy terminated polyarylate can achieved when the polyarylate is prepared in a reaction medium which is essentially homogeneous with respect to the organic reactants. Thus, in one aspect, the present invention provides a method for preparing polyarylates of almost any molecular weight in a process in which reaction of one or more dihydroxy-substituted aromatic hydrocarbon moieties with at least one dicarboxylic acid moiety is carried out under conditions which are essentially homogeneous with respect to the organic reactants. [0024] The novel method disclosed herein may be used for preparing a wide variety of hydroxy-substituted polyarylates of both high and low molecular weights and widely varying structural units. By "high molecular weight" it is meant that the polyarylate has a weight average molecular weight (Mw) in excess of 15,000 grams per mole as measured by gel permeation chromatography (GPC) using polystyrene (PS) molecular weight standards. By "low molecular weight" it is meant that the polyarylate has a weight average molecular weight of 15,000 grams per mole or less as measured by gel permeation chromatography (GPC) using polystyrene (PS) molecular weight standards. For purposes of this disclosure, the terms "oligomeric polyarylate" and "low molecular weight polyarylate" are used interchangeably. Continue reading about Coating compositions, their preparation, and coated articles made therefrom... Full patent description for Coating compositions, their preparation, and coated articles made therefrom Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Coating compositions, their preparation, and coated articles made therefrom patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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