Anticorrosion zinc primer coating composition comprising hollow glass spheres and conductive pigments

Abstract

The present invention relates to an anti-corrosion zinc primer coating composition comprising hollow glass spheres and a conductive pigment. The coating composition of the present invention is particularly suitable for protecting iron and steel structures. In particular, the coating composition of the present invention comprises: a) a binder system, b) zinc particles, c) hollow glass microspheres, and d) a conductive pigment. The present invention also relates to a kit comprising the composition, a method for applying the composition, and a metal structure coated with the composition.

Description

[0001] This application is a divisional application of a Chinese patent application filed on July 12, 2013, with application number "201380045540.5" and invention name "Anti-corrosion zinc primer coating composition containing hollow glass spheres and conductive pigments". Technical Field

[0002] The present invention relates to the field of anti-corrosion coating compositions, in particular coating compositions for protecting iron and steel structures. In particular, the present invention relates to coating compositions, such as epoxy resin-based coatings, comprising particulate zinc, conductive pigments and glass microspheres. Background Art

[0003] Zinc primers, both organic and inorganic, are widely used in the marine and shipping industries and may also be specified, for example, for steel components of bridges, vessels, refineries, the petrochemical industry, power plants, storage tanks, cranes, windmills, and civil structures such as airports, tachymeters, and high-rise buildings. Such coatings can be based on several binder systems, such as those based on silicates, epoxies, polyurethanes, cyclized rubbers, phenoxy resins, epoxy esters, urethane alkyds, and the like.

[0004] In zinc primers, zinc is used as a conductive pigment to create an anodic-active coating. The zinc acts as a sacrificial anode material and protects the steel substrate, which becomes the cathode. Corrosion resistance depends on the zinc primer's ability to transmit galvanic current, but as long as the system's conductivity is maintained and sufficient zinc is present to act as an anode, the steel will be electrically protected. Consequently, the zinc pigment particles in zinc primers are tightly packed together, and zinc primers are typically formulated with very high zinc powder loadings.

[0005] Various methods have been used in the art to reduce zinc loading. US 4,621,024 discloses coating microspheres having a metal substrate such as zinc, which results in an overall reduction in the metal component of the coating. US 5,252,632 discloses the use of non-coated hollow glass microspheres to improve the corrosion protection of zinc-based coating compositions and reduce the density of the compositions. US 5,580,907 and US 6,287,372 both disclose further efforts to reduce the amount of zinc dust in the composition by incorporating microspheres. WO 2008 / 125610 discloses the inclusion of certain zinc alloys to improve the corrosion protection of coating compositions. It also discloses that conductive pigments such as carbon black can improve corrosion inhibition.

[0006] WO 96 / 29372 discloses dry coating compositions dissolved in situ in a solvent, which dry coating compositions comprise graphite in order to avoid hard settling of the coating composition.

[0007] WO 99 / 58274 discloses a coating composition comprising carbon-modified zinc dust, zinc dust and hollow glass spheres in an epoxy ester resin matrix. The carbon-modified zinc dust is not a simple mixture of carbon and zinc.

[0008] However, there remains a need to improve the corrosion resistance of steel-based metal structures in a manner that is cost-effective and limits the amount of zinc applied to the protective coating.

[0009] In order to set up enough corrosion protection and ensure the best performance of coating, it is necessary to describe in detail the requirements of protective paint system and the relevant laboratory performance test of evaluating its possible durability. The use of new technology and paint formulation also means that coating will be developed in the situation of few or no previous records. This has caused more emphasis to be placed on the laboratory test of accelerating the evaluation of coating performance. Many of these accelerated exposure tests will not demonstrate the adverse effect on the surface of complete coating visually within its exposure time. Therefore, the behavior of the coating around the damage caused by human factors, for example scratches, has been given important consideration and many prequalification tests are based on rust creep (rust creep) and blistering (blistering) and from the detachment of scoring, ISO 12944, NORSOK M-501, ISO 20340, NACE TM 0104, 0204, 0304, 0404 etc. (Weinell, CE and SN Rasmussen, Advancement in zinc rich epoxy primers for corrosion protection, NACE International, paper no.07007 (2007)). These accelerated weathering methods seek to intensify the environmental impact so that film failure occurs more rapidly (Mitchell, MJ, Progress in offshore coatings, NACE International, paper no. 04001 (2004)). The lower the rust creep, the better the overall corrosion protection. Summary of the Invention

[0010] Improved corrosion resistance of steel-based metal structures is achieved with a coating composition comprising:

[0011] a) an adhesive system selected from epoxy resin-based adhesive systems, polysiloxane-based adhesive systems, polyurethane-based adhesive systems, cyclized rubber-based adhesive systems and phenoxy resin-based adhesive systems,

[0012] b) zinc particles,

[0013] c) hollow glass microspheres, and

[0014] d) Conductive pigments selected from the group consisting of graphite, carbon black, aluminum pigments, black iron oxide, antimony-doped tin oxide, mica coated with antimony-doped tin oxide, indium tin oxide, carbon nanotubes, carbon fibers, and any mixtures thereof.

[0015] In one embodiment, in order to provide particularly good corrosion resistance, the coating composition according to the invention comprises an electrically conductive pigment selected from carbon black, graphite and any mixtures thereof. DETAILED DESCRIPTION

[0016] It should be understood that the present invention is applicable in principle to any type of binder system into which zinc powder can be incorporated, such as conventional anticorrosion coating compositions. Some examples thereof are coating compositions comprising a binder system selected from the group consisting of epoxy resin-based binder systems, polysiloxane-based binder systems, polyurethane-based binder systems, cyclized rubber-based binder systems, and phenoxy resin-based binder systems. In one embodiment, the coating composition of the present invention comprises a binder system selected from the group consisting of epoxy resin-based binder systems, polyurethane-based binder systems, and polysiloxane-based binder systems. In another embodiment, the coating composition of the present invention comprises a binder system selected from the group consisting of epoxy resin-based binder systems and polysiloxane-based binder systems. In yet another embodiment, the binder system is an epoxy resin-based binder system.

[0017] Epoxy resin-based adhesive systems

[0018] The term "epoxy-based adhesive system" should be understood as a combination of one or more epoxy resins, any curing agent, any reactive epoxy diluent, any epoxy modifier, any extender resin, any epoxy accelerator, and any epoxy toughening agent.

[0019] Examples of suitable reactive epoxy resin diluents include monofunctional glycidyl ethers or esters of aliphatic, cycloaliphatic or aromatic compounds, such as Araldite DY-E / BD (from Huntsman Advanced Materials - Germany), Cardolite NC 513 (from Cardanol Chemicals (US)) and Cardura E10P (from Momentive - The Netherlands).

[0020] Examples of suitable epoxy resin modifiers include, for example, oils, oil derivatives, modified oils such as linseed oil and its derivatives, castor oil and its derivatives, soybean oil and its derivatives.

[0021] Examples of suitable extender resins include, for example, saturated polyester resins, polyvinyl acetate, polyvinyl butyrate, copolymers of vinyl acetate and vinyl isobutyl ether, copolymers of vinyl chloride and vinyl isobutyl ether, polyvinyl methyl ether, polyvinyl isobutyl ether, polyvinyl ethyl ether, modified aromatic hydrocarbon resins; styrene copolymers such as styrene / butadiene copolymers; acrylic resins; hydroxy-acrylate copolymers; fatty acids; and cyclized rubbers.

[0022] Epoxy resin-based adhesive systems may comprise one or more epoxy resins selected from aromatic or non-aromatic epoxy resins (e.g., hydrogenated epoxy resins) containing more than one epoxy group per molecule, located internally, at the terminal end, or on a ring structure, and any suitable curing agent acting as a crosslinking agent. In order to reduce viscosity and improve application and physical properties, a combination with a reactive diluent such as a monofunctional glycidyl ether or ester from aliphatic, alicyclic, or aromatic compounds may be included.

[0023] Suitable epoxy resin-based adhesive systems are considered to include epoxy resins and modified epoxy resins selected from the group consisting of bisphenol A, bisphenol F, novolac epoxy resins, non-aromatic epoxy resins, cycloaliphatic epoxy resins, epoxidized polysulfides, and epoxy-functional acrylic resins, or any combination thereof. A particular epoxy resin-based adhesive system includes bisphenol A. The epoxy resin-based adhesive system can be a conventional type such as solvent-based and water-based epoxy resin-based epoxy resin-based adhesive systems.

[0024] Examples of suitable commercially available solvent-based epoxy resins are:

[0025] Epikote 828, from Momentive (US), bisphenol A type

[0026] Araldite GY 250, from Huntsman Advanced Materials (Switzerland), bisphenol A type

[0027] Epikote 1004, from Momentive (US) bisphenol A type

[0028] DER 664-20, from Dow Chemicals (Germany), bisphenol A type

[0029] Epikote 1001X 75, from Momentive (US), bisphenol A type

[0030] Araldite GZ 7071X75BD, from Huntsman Advanced Materials (Germany), bisphenol A in xylene

[0031] Araldite GZ 7071X75CH, from Huntsman Advanced Materials (Switzerland), bisphenol A type

[0032] DER 352, from Dow Chemicals (Germany), a mixture of bisphenol A and bisphenol F

[0033] Epikote 235, from Momentive (US), a mixture of bisphenol A and bisphenol F

[0034] Epikote 862, from Momentive (US), bisphenol F type

[0035] DEN 438-X 80, from Dow Chemical Company (US), novolac epoxy resin

[0036] Epikote 1009, from Momentive (US), bisphenol A type

[0037] DER 684-EK40, from Dow Chemicals (Germany), bisphenol A type

[0038] Epikote 154, from Momentive (US) novolac epoxy resin

[0039] Examples of suitable commercially available waterborne epoxy resins are:

[0040] Beckopox EP 385W, from Cytex Surface Specialities (Germany)

[0041] Epicote 3540WY-55A, from Momentive (US)

[0042] EPI-REZ DPW 6520, from Momentive (US)

[0043] Beckopox VEP 2381W, from Cytex Surface Specialities (Germany)

[0044] The epoxy resin-based adhesive system may comprise one or more curing agents selected from compounds or polymers comprising at least two reactive hydrogen atoms attached to nitrogen.

[0045] Suitable curing agents for solventborne epoxy resins are believed to include amines or amino-functional polymers selected from the group consisting of aliphatic amines and polyamines (e.g., cycloaliphatic amines and polyamines), polyamidoamines, polyoxyalkylene amines (e.g., polyoxyalkylene diamines), aminated polyalkoxy ethers (e.g., those commercially available as "Jeffamines"), alkylene amines (e.g., alkylenediamines), aralkylamines, aromatic amines, Mannich bases (e.g., those commercially available as "phenalkamines"), amino-functional siloxanes or silanes, isocyanates, and amine adducts and derivatives thereof. In one embodiment, the curing agent is a polyamidoamine.

[0046] Examples of suitable commercially available curing agents are:

[0047] Jeffamine EDR-148, from Huntsman Corporation (USA), triethylene glycol diamine

[0048] Jeffamine D-230, from Huntsman Corporation (USA), polyoxypropylene diamine

[0049] Jeffamine D-400, from Huntsman Corporation (USA), polyoxypropylene diamine

[0050] Jeffamine T-403, from Huntsman Corporation (USA), polyoxypropylene triamine

[0051] Ancamine 1693, from Air Products (USA), a cycloaliphatic polyamine adduct

[0052] Ancamine X2280, from Air Products (USA), cycloaliphatic amine

[0053] Ancamine 2074, from Air Products (USA), a cycloaliphatic polyamine adduct

[0054] Ancamide 350A, from Air Products (USA), polyaminoamide

[0055] Sunmide CX-105X, from Air Products Inc., Mannich base

[0056] Epikure 3140 curing agent, from Momentive (USA), polyamidoamine

[0057] SIQ Amin 2030, from SIQ Kunstharze GmbH (Germany), polyamidoamine

[0058] Epikure 3115X-70 curing agent, from Momentive (USA), polyamidoamine

[0059] SIQ Amin 2015, from SIQ Kunstharze GmbH (Germany), polyamidoamine

[0060] Polypox VH 40309 / 12, from Dow Chemicals (USA), polyoxyalkylene amine

[0061] CeTePox 1490H, from CTP Chemicals and Technologies for Polymers (Germany), polyoxyalkylene amine

[0062] Epoxy curing agent MXDA, from Mitsubishi Gas Chemical Company Inc (USA), arylalkylamine

[0063] Diethylaminopropylamine, from BASF (Germany), a fatty amine

[0064] Gaskamine 240, from Mitsubishi Gas Chemical Company Inc (USA), arylalkylamine

[0065] Cardolite Lite 2002, from Cardanol Chemicals (USA), Mannich base

[0066] Aradur 42BD, from Huntsman Advanced Materials (Germany), cycloaliphatic isophorone diamine, from BASF (Germany), cycloaliphatic amine

[0067] Epikure 3090 curing agent, from Momentive (USA), a polyamidoamine adduct with epoxy

[0068] Crayamid E260 E90, from Arkema (France), polyamidoamine adducts with epoxy

[0069] Crayamid 140, from Arkema (France), amino polyamide resin

[0070] Aradur 943CH, from Huntsman Advanced Materials (Switzerland), alkyleneamine adduct with epoxy

[0071] Aradur 863XW 80CH, from Huntsman Advanced Materials (Switzerland), an aromatic amine adduct with epoxy

[0072] Cardolite NC-541, from Cardanol Chemicals (USA), Mannich base

[0073] Cardolite Lite 2001, from Cardanol Chemicals (USA), Mannich base

[0074] Suitable curing agents for waterborne epoxy resins may include amine adducts selected from:

[0075] Beckopox EH 623W, from Cytex Surface Specialities (Germany)

[0076] Beckopox EH 613W, from Cytex Surface Specialities (Germany)

[0077] EPICURE DPC 6870, from Momentive (US)

[0078] Epilink660, from Air Products (Italy)

[0079] Epilink 701, from Air Products (UK)

[0080] In one embodiment, the epoxy resin-based adhesive system comprises a) one or more epoxy resins selected from bisphenol A, bisphenol F, and novolac; and b) one or more curing agents selected from Mannich bases, polyamidoamines, polyoxyalkyleneamines, alkyleneamines, arylalkylamines, polyamines, and adducts and derivatives thereof. In yet another embodiment, the epoxy resin-based adhesive system may comprise both bisphenol A and polyamidoamines.

[0081] In another embodiment, the epoxy equivalent weight of the epoxy resin may be 100-9000, 100-2000, such as 100-1500, such as 150-1000, such as 150-700.

[0082] In yet another embodiment, the epoxy-based adhesive system may comprise one or more bisphenol A epoxy resins having an epoxy equivalent weight of 150-700 and one or more polyamidoamines or adducts and derivatives thereof.

[0083] In one embodiment, the epoxy-based adhesive system is an ambient cure adhesive system.

[0084] For some epoxy resin based adhesive systems, the composition will form a suitable film without the addition of a curing agent.Thus, in another embodiment, no curing agent is added to the paint composition.

[0085] In one embodiment, the total amount of the epoxy-based binder system in the coating composition may be in the range of 15% to 80%, such as 20% to 65%, for example 30% to 50% by solid volume of the coating composition.

[0086] As used herein, the term "hydrogen equivalents" is intended to encompass only the reactive hydrogen atoms attached to nitrogen.

[0087] The number of "hydrogen equivalents" associated with one or more curing agents is the sum of the individual contributions of the one or more curing agents. The contribution of each of the one or more curing agents to the hydrogen equivalents is defined as the grams of curing agent divided by the hydrogen equivalent weight of the curing agent, where the hydrogen equivalent weight of the curing agent is defined as the grams of curing agent equivalent to 1 mol of activated hydrogen. For adducts of epoxy resins, the contributions of the reactants prior to adduction are used to determine the number of "hydrogen equivalents" in the epoxy-based adhesive system.

[0088] The number of "epoxy equivalents" associated with one or more epoxy resins is the sum of the individual contributions of the one or more epoxy resins. The contribution of each of the one or more epoxy resins to the epoxy equivalent weight is defined as the number of grams of epoxy resin divided by the epoxy equivalent weight of the epoxy resin, where the epoxy equivalent weight of the epoxy resin is defined as the number of grams of epoxy resin equivalent to one mole of epoxy groups. For adducts of epoxy resins, the contributions of the reactants prior to adduction are used to determine the number of "epoxy equivalents" in the epoxy-based adhesive system.

[0089] The ratio of hydrogen equivalents of the one or more curing agents to epoxy equivalents of the one or more epoxy resins can be in the range of 20:100 to 120:100, such as 60:100 to 110:100 or 70:100 to 100:110 or such as 80:100 to 110:100.

[0090] Alternatively, the binder system of coating composition is selected from polysiloxane-based binder system, polyurethane-based binder system, cyclized rubber-based binder system and phenoxy resin-based binder system.The example of such commercial coating composition is the type that wherein zinc powder is conventionally used.According to specific binder system, binder system may need or not need curing agent.Therefore, in one embodiment, binder system comprises one or more curing agents.In another embodiment, binder system does not comprise any curing agent.

[0091] Other suitable adhesive systems include one-component coatings, such as those based on vinyl polymers; copolymers of vinyl chloride and vinyl isobutyl ether; phenoxy groups; polyurethanes; and cyclized rubbers containing aromatic hydrocarbon resins such as petroleum fraction condensates. Typically, no curing agent is added to this type of one-component adhesive system.

[0092] Examples of such commercially available resins suitable for use in one-component zinc-containing coatings are:

[0093] Alplex CK 450, Cytec (based on cyclized rubber)

[0094] Phenoxy PKHH, InChem (phenoxy-based)

[0095] Silicone-based adhesive systems

[0096] The term "polysiloxane-based adhesive system" is to be understood as an adhesive system comprising at least one curable polysiloxane-modified component, wherein the major part of the adhesive system consists of polysiloxane moieties, i.e. at least 20% by volume solids, such as at least 25% by volume solids, preferably at least 35% by volume solids, for example more than 50% by volume solids of the adhesive system is represented by polysiloxane moieties.

[0097] The polysiloxane moiety is understood to include any pendant organic substituents, such as alkyl-, phenyl- and / or saturated cyclic structures and may also include curable substituents, examples of which are alkoxy groups, unsaturated acrylic groups and the like.

[0098] In one embodiment, the polysiloxane-based adhesive system is a combination of one or more amino-functional silicone-modified compounds, one or more epoxy resins, any polysiloxane adhesive or polysiloxane-modified adhesive component, any aminosilane, any reactive epoxy resin diluent, any epoxy resin modifier, any extender resin, any epoxy resin accelerator, and any epoxy resin plasticizer.

[0099] The term "amino-functional silicone-modified compound" is to be understood in the conventional sense, ie a silicone compound, such as a silane or polysiloxane compound, having pendant and / or terminal amino groups. Illustrative examples of amino-functional silicone compounds are amino-functional polysiloxanes and aminosilanes.

[0100] In yet another embodiment of the present invention, the amino-functional silicone compound is an amino-functional polysiloxane. The term "amino-functional polysiloxane" means a linear or branched polymeric component having one or more polysiloxane blocks and having pendant and / or terminal amino functional groups.

[0101] For example, amino functional groups can be introduced into reactive polysiloxanes with the aid of aminosilanes (i.e., such as those defined below), as described in US Pat. No. 4,857,608. It should also be understood that amino functional polysiloxanes can be prepared in situ. In some examples, amino functional groups are introduced by reacting a hydroxyl-functional or alkoxy-functional polysiloxane with an aminosilane. For example, an aminosilane can be reacted with an α,ω-dihydroxy polydimethylsiloxane at a temperature ranging from 20°C to 80°C, preferably using 0.4 to 5.0 alkoxy groups of the aminosilane for each silanol group of the polysiloxane. If an excess of aminosilane is used or if the reaction is not allowed to proceed to completion, a small amount of aminosilane may remain in the product. In one embodiment, the at least one amino functional polysiloxane is the reaction product of a polysiloxane and an aminosilane.

[0102] Examples of amino-functional polysiloxanes are α,ω-diamino-functional polysiloxanes (e.g., polysiloxane fluids). Illustrative examples of commercially available amino-functional polysiloxanes are SILRES HP 2000 (amino-functional methyl-phenyl silicone) from Wacker Chemie, Germany; SF1708 (amino-functional polysiloxane fluid) from General Electric Co., etc.

[0103] In another embodiment, the aminofunctional silicon compound is an aminosilane. In this embodiment, it is preferred that a polysiloxane adhesive or polysiloxane-modified adhesive component be present that acts as a reactive plasticizer / co-binder. Aminosilanes are generally defined as silanes of the formula:

[0104] (RO) x R 3-x SiR 1 NHR 2

[0105] wherein each R is independently selected from C 1-8 -alkyl (e.g., methyl, ethyl, hexyl, octyl, etc.), C 1-4 -alkyl-OC 2-4 -alkyl; aryl (e.g., phenyl) and aryl-C1-4 -alkyl (eg, benzyl); R 1 Selected from -(CH2) 2-4 -, methyl substituted trimethylene and -(CH2) 2-3 -O-(CH2) 2-3 ; R 2 selected from hydrogen and -(CH2) 2-4 -NH2; x is an integer of 0-3 such as 0, 1, 2 or 3.

[0106] Illustrative examples of aminosilanes are (CH3O)3Si(CH2)3NH(CH2)2NH2; (CH3CH2OCH2CH2O)3Si(CH2)2NH2; (C2H5O)3Si(CH2)3NH2; (CH3OCH2CH2O)3Si(CH2)3NH2; (C2H5O)3Si(CH2)3O(CH2)3NH2; (C2H5O)2C6H5Si(CH2)3NH2; (C2H5O)3SiCH2O(CH2)2NH2; (C2H5O)3Si(CH2)3O(CH2)2NH2 and (C2H5O)2CH3Si(CH2)3NH2. Illustrative examples of commercially available aminosilanes are Dynasilan AMEO (3-aminopropyltriethoxysilane) from Degussa Hüls; KBM603 (N-β-aminoethyl-γ-aminopropyltrimethoxysilane) from Shin Etsu et al.

[0107] Examples of the "polysiloxane adhesive or polysiloxane-modified adhesive" include polysiloxanes having the following formula:

[0108]

[0109] Where n is an integer from 3 to 50, and each R 1 Independently selected from C 1-6 -alkyl (e.g., methyl, ethyl, etc.); C 1-6 -hydroxyalkyl (eg, hydroxymethyl, hydroxyethyl, etc.); C 1-6 -alkoxy (e.g., methoxy, ethoxy, propoxy, etc.) and each R 2 Independently selected from silanol, C 1-6 -alkyl (e.g., methyl, ethyl, etc.); C 1-6 -hydroxyalkyl (eg, hydroxymethyl, hydroxyethyl, etc.); C 1-6 - Alkoxy groups (eg, methoxy, ethoxy, propoxy, etc.) In one embodiment, the polysiloxane adhesive or polysiloxane-modified adhesive is a polysiloxane adhesive containing a methoxy group.

[0110] In yet another embodiment, the amino-functional silicon compound is a combination of an amino-functional polysiloxane and an aminosilane, i.e., the adhesive phase comprises one or more amino-functional polysiloxanes and one or more aminosilanes. This combination can be accomplished by adding an amino-functional polysiloxane (as described above) and an aminosilane (as described above) or by using a reaction product between an aminosilane and a polysiloxane in which a portion of the aminosilane remains unreacted.

[0111] The "one or more epoxy resins" are similar to the epoxy resins described above in the epoxy resin-based adhesive system section.

[0112] Examples of suitable commercially available epoxy resins include, for example, Adeka resin EP-4080E ADEKA Corporation - Japan (aliphatic epoxy resin) and Epikote 828, from Momentive (US), bisphenol A type.

[0113] Further suitable silicone-based adhesive systems are described, for example, in WO 96 / 16109, WO 01 / 51575 and WO 2009 / 823691.

[0114] Polyurethane-based adhesive systems

[0115] The term "polyurethane adhesive system" is intended to mean an adhesive system having as main components one or more diisocyanate or polyisocyanate components and a hydroxy-functional component containing two or more hydroxyl groups (two-component system) or an adhesive system having as main components one or more isocyanate prepolymers (typically a one-component system).

[0116] The reaction (curing) of the isocyanate component and the hydroxyl functional component results in the formation of urethane functional groups.

[0117] One type of polyurethane-based adhesive system comprises:

[0118] a) polyisocyanate component and

[0119] b) a hydroxy-functional component comprising at least two hydroxyl groups.

[0120] The crosslinking that occurs is based on the reaction between the polyisocyanate component a) and the hydroxy-functional component b).

[0121] Suitable polyisocyanates for use as the polyisocyanate component a) in the composition include the known polyisocyanates of polyurethane chemistry. Examples of suitable low molecular weight polyisocyanates having a molecular weight of 168 to 300 include hexamethylene diisocyanate (HDI), 2,2,4- and / or 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,4-diisocyanato-1-methyl-benzene (toluene diisocyanate, TDI), 2,4-diisocyanato-1-toluene, 1,4-diisocyanatocyclohexane, 1-isocyanato- 3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4′- and / or 4,4′-diisocyanatodicyclohexylmethane, 2,4- and / or 4,4′-diisocyanatodiphenylmethane and mixtures of these isomers with their higher homologues obtained in a known manner by phosgenation of aniline / formaldehyde condensates, 2,4- and / or 2,6-diisocyanatotoluene and any mixtures of these compounds.

[0122] In one embodiment, the one or more polyisocyanates are selected from aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), 2,2,4- and / or 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 2,4′- and / or 4,4′-diisocyanato-dicyclohexylmethane and 2,4- and / or 4,4′-diisocyanato-diphenylmethane.

[0123] In some variations thereof, the coating composition further comprises one or more catalysts, for example, one or more selected from the group consisting of tetramethylbutanediamine (TMBDA), N-alkylmorpholine, triethylamine (TEA), 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), pentamethyldiethylenetriamine (PMDETA), zinc octoate, dioctyltin dilaurate, dibutyltin dilaurate, and dibutyltin oxide, in particular selected from the group consisting of dioctyltin dilaurate, dibutyltin dilaurate, and dibutyltin oxide. In other variations, the coating composition does not contain any of these catalysts.

[0124] In one embodiment, the one or more polyisocyanates are chosen from aromatic polyisocyanates, for example 2,4-diisocyanato-1-methyl-benzene (toluene diisocyanate, TDI), 2,4-diisocyanato-1-methyl-benzene and mixtures of these isomers with their higher homologues obtained in a known manner by phosgenation of aniline / formaldehyde condensates, 2,4- and / or 2,6-diisocyanatotoluene and any mixtures of these compounds.

[0125] However, preference is given to using derivatives of polyisocyanates of these monomers, since these are conventional in coating technology. These derivatives comprise polyisocyanates containing diurea groups.

[0126] Particularly preferred modified polyisocyanates are: N,N′,N″-tris-(6-isocyanatohexyl)-diurea and mixtures thereof with its higher homologs and N,N′,N″-tris-(6-isocyanatohexyl)-isocyanurate and mixtures thereof with its higher homologs containing more than one isocyanurate ring.

[0127] Examples of suitable commercially available polyisocyanate resins are:

[0128] Desmodur N3900 (formerly VP2410), from Bayer (Germany), aliphatic polyisocyanate

[0129] Desmodur N3600, from Bayer (Germany), aliphatic polyisocyanate

[0130] Desmodur N3800, from Bayer (Germany), aliphatic polyisocyanate

[0131] Tolonate HDT-LV2, from Rhodia (France), aliphatic polyisocyanate

[0132] Desmodur N3390, from Bayer (Germany), aliphatic polyisocyanate

[0133] Tolonate HDT90, from Rhodia (France), aliphatic polyisocyanate

[0134] Basonat HI 190B / S, from BASF (Germany), aliphatic polyisocyanate

[0135] Desmodur N75, from Bayer (Germany), aliphatic polyisocyanate

[0136] Bayhydur VP LS2319, from Bayer (Germany), aliphatic polyisocyanate

[0137] Tolonate IDT 70B, from Rhodia (France), aliphatic polyisocyanate

[0138] Desmodur H, from Bayer (Germany)

[0139] Basonat HB 175MP / X BASF-Germany, aliphatic polyisocyanate

[0140] Examples of suitable commercially available aromatic polyisocyanate resins are:

[0141] Desmodur L67 BA(Bayer Material Science)

[0142] Desmodur E21(Bayer Material Science)

[0143] Desmodur VL (Bayer Material Science)

[0144] Voratron EC 112(Dow Chemicals)

[0145] Desmodur E23(Bayer Material Science)

[0146] Desmodur E 1660 (Bayer Material Science)

[0147] Suprasec 2495 (Huntsman Advanced Materials).

[0148] Isocyanate group-containing prepolymers and semi-prepolymers based on monomeric simple or modified polyisocyanates as exemplified above and organic polyols are also preferably used as polyisocyanate component a). These prepolymers and semi-prepolymers generally have an isocyanate content of 0.5% to 30% by weight, preferably 1% to 20% by weight, and are prepared in a known manner by reacting the above-mentioned starting materials at an NCO / OH equivalent ratio of 1.05:1 to 10:1, preferably 1.1:1 to 3:1, which reaction is optionally followed by distillative removal of any unreacted, non-volatile starting polyisocyanates still present.

[0149] Prepolymers and semi-prepolymers can be suitably prepared from the following: low molecular weight polyols having a molecular weight of 62 to 299, such as ethylene glycol, propylene glycol, trimethylolpropane, 1,6-dihydroxyhexane; low molecular weight hydroxyl-containing esters of these polyols with dicarboxylic acids of the type exemplified below; low molecular weight ethoxylation and / or propoxylation products of these polyols; and mixtures of the aforementioned polyvalent modified or unmodified alcohols.

[0150] However, the prepolymers and semi-prepolymers are preferably prepared from relatively high molecular weight polyols.

[0151] These polyols have at least two hydroxyl groups per molecule (and generally have a hydroxyl content of 0.5% to 17% by weight, preferably 1% to 5% by weight).

[0152] Examples of suitable relatively high molecular weight polyols that can be used to prepare the prepolymers and semi-prepolymers include those based on the aforementioned low molecular weight polyester polyols.

[0153] Examples of commercially available polyester polyols include:

[0154] Desmophen 651MPA, from Bayer (Germany)

[0155] Desmophen VP LS2089, from Bayer Material Science (Germany)

[0156] Polyether polyols (which are obtained in a known manner by alkoxylation of suitable starter molecules) are also suitable for preparing isocyanate-containing prepolymers and semi-prepolymers. Examples of suitable starter molecules for polyether polyols include the aforementioned monomeric polyols, water, and any mixtures of these starter molecules. Ethylene oxide and / or propylene oxide (polylene oxide) are particularly suitable alkylene oxides for the alkoxylation reaction. These alkylene oxides can be introduced into the alkoxylation reaction in any order or as a mixture.

[0157] Examples of commercially available polyether polyols include:

[0158] Desmophen 1380BT 03 / 2008 (previously Desmophen 550U), from Bayer Material Science (Germany)

[0159] Voranol CP 450 Polyol, from Dow Chemicals (Germany)

[0160] Also suitable for the preparation of prepolymers and semi-prepolymers are hydroxyl-containing polycarbonates (which can be prepared by reaction of the aforementioned monomeric diols with phosgene and diaryl carbonates, such as diphenyl carbonate).

[0161] Component b) is based entirely or partly on organic polyols known from polyurethane chemistry and comprises low molecular weight polyols and relatively high molecular weight polyols as described above for the preparation of prepolymers and semi-prepolymers suitable as polyisocyanate component a).

[0162] Particularly preferred hydroxyl-functional, isocyanate-reactive compounds useful as component b) are the hydroxyl-functional polyacrylates known for use in polyurethane coatings. These compounds are hydroxyl-containing copolymers of ethylenically unsaturated compounds having a number-average molecular weight (Mn), as measured by vapor pressure osmometry, of 800 to 50,000, preferably 1000 to 20,000, and more preferably 5000 to 10,000, and a hydroxyl content of 0.1% to 12% by weight, preferably 1% to 10% by weight, and most preferably 2% to 6% by weight. The copolymers are based on hydroxyl-containing olefin monomers and hydroxyl-free olefin monomers. Examples of suitable monomers include vinyl and vinylidene monomers such as styrene, α-methylstyrene, o- and p-chlorostyrene, o-, m- and p-methylstyrene, p-tert-butylstyrene; acrylic acid, (meth)acrylonitrile; acrylic and methacrylic esters of alcohols containing 1 to 8 carbon atoms such as ethyl acrylate, methyl acrylate, n- and isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid, butyl ester and isooctyl methacrylate; diesters of fumaric acid, itaconic acid, or maleic acid having 4 to 8 carbon atoms in the alcohol portion; (meth)acrylic acid amides; vinyl esters of alkane monocarboxylic acids having 2 to 5 carbon atoms, such as vinyl acetate or vinyl propionate; and hydroxyalkyl esters of acrylic acid or methacrylic acid having 2 to 4 carbon atoms in the hydroxyalkyl group, such as 2-hydroxyethyl-, 2-hydroxypropyl-, 4-hydroxybutyl-acrylate and methacrylate, as well as trimethylolpropane-mono- or pentaerythritol-mono-acrylate or methacrylate. Mixtures of the aforementioned exemplary monomers can also be used to prepare hydroxy-functional polyacrylates. Mixtures of the aforementioned polyols can be used as component b).

[0163] In this type of polyurethane-based adhesive system, components a) and b) are used in amounts sufficient to provide an equivalent ratio of isocyanate groups to isocyanate-reactive (hydroxyl) groups of 0.8:1 to 20:1, preferably 0.8:1 to 2:1, more preferably 0.8:1 to 1.5:1, even more preferably 0.8:1 to 1.2:1, and most preferably about 1:1. The hydroxyl-functional compound b) is present in an amount such that up to 20 hydroxyl groups are present; preferably, the equivalent ratio of hydroxyl groups to secondary amino groups is from 10:1 to 1:10.

[0164] Examples of suitable commercially available hydroxy-functional (isocyanate-reactive) resins include:

[0165] Synocure 878N 60, from Arkem (Spain), a hydroxy-functional acrylic resin in an aromatic hydrocarbon

[0166] Synthalat A0 77, from Synthopol Chemie (Germany)

[0167] Synthalat A045, from Synthopol Chemie (Germany)

[0168] Synthalat A088MS, from Synthopol Chemie (Germany)

[0169] Synthalat A141HS 05, from Synthopol Chemie (Germany)

[0170] Synthalat A060, from Synthopol Chemie (Germany)

[0171] Desmophen AXP 2412, from Bayer Material Science (Germany)

[0172] Synthalat A-TS1603, from Synthopol Chemie (Germany)

[0173] Acrylamac 332-2629, from Momentive (Germany)

[0174] Polyurethane coating systems of the type described above are typically applied as a two-component system, with one package containing the hydroxyl-containing component, any pigments, solvents, and additives, and the other package containing the polyisocyanate-containing compound and anhydrous solvent. Zinc particles, conductive pigments, and hollow glass microspheres are typically added to the hydroxyl-containing package. Examples of such coatings are provided in Table 9.

[0175] Another type of polyurethane coating system is a one-component system in which all components are provided in the same container and the paint is moisture cured (typically at ambient temperature and conditions or slightly elevated temperatures, such as 60° C. to 100° C.), optionally in the presence of an accelerator, such as a tin-containing accelerator. Examples of such coatings are provided in Table 8.

[0176] In one embodiment, the moisture-cured polyurethane-based adhesive system comprises one or more isocyanate prepolymers such as toluene diisocyanate (TDI)-based polyisocyanate prepolymers.

[0177] Examples of suitable commercially available isocyanate prepolymers include:

[0178] Desmodur E21(Bayer Material Science)

[0179] Desmodur E1361(Bayer Material Science)

[0180] Desmodur E14(Bayer Material Science)

[0181] Desmodur E23(Bayer Material Science)

[0182] Desmodur E 1660 (Bayer Material Science)

[0183] Voratron EC 112(Dow Chemicals)

[0184] Polyurethane coating systems of the type described above are typically supplied as a one-component system, wherein the package contains one or more isocyanate prepolymers, conductive pigments, zinc particles, hollow glass microspheres, and any non-conductive pigments, fillers, solvents, additives, and the like.

[0185] Zinc particles

[0186] Materials referred to as "zinc granules" are particulate materials having a high zinc content, such as at least 90% by weight zinc.

[0187] The term "granular material" is meant to encompass small spherical or slightly irregularly shaped particles and other shapes such as flakes, discs, spheres, needles, platelets, fibers and rods. The granular material may be a powder or dust.

[0188] The particle size distribution of the particulate material is of some importance in paint applications. For example, a particulate material that is too coarse will result in particles sticking through the dry paint film. Therefore, in one embodiment, D 50 In another embodiment, D 50 In another embodiment, the particle material is less than 20 μm. 50 Particulate material smaller than 15 μm, and in yet another embodiment, D 50 Particulate material smaller than 12 μm.

[0189] In addition to the above, particles coarser than 100 μm should be avoided as much as possible, as they may protrude from the paint film. This will cause defects in the paint film and deteriorate the barrier effect and anti-corrosion properties. Therefore, it is useful to discard any particles larger than 100 μm, for example by screening. In practice, D 99Less than 100 μm is considered suitable.

[0190] For example, you can use Sympatec GmbH laser diffraction equipment is used to measure the particle size distribution of the material. Parameter D 50 and D 99 are the equivalent particle sizes of the volume cumulative distribution, Q3, assumed to be the 50th and 99th percentile values, respectively.

[0191] The granular material can be produced by conventional gas atomization of the corresponding crude zinc material. Since the granular material obtained directly from this method still contains coarse particles that are incompatible with the intended application, a screening or classification operation must be performed.

[0192] The zinc particles included in the present invention are also commercially available. Suppliers include Purity Zinc Metals, Horsehead Corporation, Umicore, US Zinc, Jiashan Baiwei, and Garrison Minerals, for example, ZMP 4P16, Umicore (Belgium).

[0193] In one embodiment, the zinc particles are present in the coating composition of the present invention in an amount of about 10% to 55% by solid volume of the mixed coating composition, such as about 15% to 50% by solid volume, for example about 18% to 40% by solid volume, more particularly about 20% to about 36% by solid volume, and even more particularly about 20% to about 30% by solid volume. In another embodiment, the zinc particles are present in the coating composition of the present invention in an amount of about 30% to 50% by solid volume of the mixed coating composition, such as 35% to 45% by solid volume.

[0194] Hollow glass microspheres

[0195] Uncoated hollow glass microspheres are commercially available from suppliers including 3M Corporation, Minerals i Derivats SA, and Potter Industries.

[0196] Potter Industries sells their trademarked Hollow glass microspheres. Available in different sizes, named 110P8, 60P18, 45P25, 34P30 and 25P45 110P8 microspheres are slightly heavier than water (in terms of specific gravity) and have a true density of 1.1 g / ml, while 60P18, 45P25, 34P30, and 25P45 have densities of 0.60 g / ml, 0.45 g / ml, 0.34 g / ml, and 0.25 g / ml, respectively. Their maximum operating pressures are 10,000 psi, 8,000 psi, 4,000 psi, 3,000 psi, and 750 psi, respectively.

[0197] Microspheres supplied by Minerals i Derivats SA under the name ESFERIGLASS-U6 (produced by LarandChem Corp., US) are spherical, white, ultra-low density glass spheres with a true density of 0.224 g / cc, a bulk density of 0.16 g / cc, and an oil absorption of 38 g / 100 cc. The particle size of these microspheres is: 10% less than 15 μm, 50% less than 25 μm, and 90% less than 40 μm.

[0198] Coated hollow glass microspheres can be prepared from uncoated hollow glass microspheres according to the method disclosed in US 4,621,024. However, in a currently preferred embodiment of the present invention, the hollow glass microspheres contained in the coating composition of the present invention are uncoated.

[0199] The density of the hollow glass microspheres can affect the performance of the coating composition. Therefore, currently, in one embodiment, the true density of the hollow glass microspheres is about 0.05 g / cc to 0.75 g / cc, such as 0.1 g / cc to 0.5 g / cc, such as about 0.2 g / cc to 0.4 g / cc.

[0200] In another embodiment of the coating composition of the present invention, the hollow glass microspheres are uncoated and have a true density of about 0.05 g / cc to 0.75 g / cc, for example, 0.1 g / cc to 0.5 g / cc, such as about 0.2 g / cc to 0.4 g / cc.

[0201] In yet another embodiment of the coating composition of the present invention, the hollow glass microspheres have a particle size of: 90% of the particles have a diameter of less than 120 μm, such as less than 100 μm, for example less than 60 μm, more particularly less than 50 μm.

[0202] In another embodiment of the coating composition of the present invention, the hollow glass microspheres have an average particle size of 50% with a diameter of less than 80 μm, such as less than 70 μm, for example less than 60 μm or less than 50 μm, more particularly less than 45.

[0203] The hollow glass microspheres are present in the coating compositions of the present invention in an amount suitable for achieving improved corrosion resistance. Thus, in one embodiment, the hollow glass microspheres are present in an amount of about 10% to 30% by solid volume, such as 15% to 25% by solid volume, for example, 18% to 24% by solid volume, of the mixed paint composition. In another embodiment, the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, such as 15% to 25% by solid volume, for example, 18% to 24% by solid volume. In yet another embodiment, the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, such as 15% to 25% by solid volume, for example, 18% to 24% by solid volume, and 90% have a diameter of less than 120 μm, such as less than 100 μm, for example, less than 60 μm, more particularly less than 50 μm. More specifically, in this further embodiment, the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, and 90% have a diameter of less than 120 μm; the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, and 90% have a diameter of less than 100 μm; the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, and 90% have a diameter of less than 60 μm; the hollow glass microspheres are uncoated and present in an amount of about 10% to 30% by solid volume, and 90% have a diameter of less than 50 μm; the hollow glass microspheres are uncoated and present in an amount of about 15% to 25% by solid volume, and 90% have a diameter of less than 120 μm; the hollow glass microspheres are uncoated and present in an amount of about 15% to 25% by solid volume, and 90% have a diameter of less than The hollow glass microspheres are uncoated and present in an amount of about 15% to 25% by solid volume, and 90% have a diameter of less than 60 μm; the hollow glass microspheres are uncoated and present in an amount of about 15% to 25% by solid volume, and 90% have a diameter of less than 50 μm; the hollow glass microspheres are uncoated and present in an amount of about 18% to 24% by solid volume, and 90% have a diameter of less than 120 μm; the hollow glass microspheres are uncoated and present in an amount of about 18% to 24% by solid volume, and 90% have a diameter of less than 100 μm; the hollow glass microspheres are uncoated and present in an amount of about 18% to 24% by solid volume, and 90% have a diameter of less than 60 μm; the hollow glass microspheres are uncoated and present in an amount of about 18% to 24% by solid volume, and 90% have a diameter of less than 50 μm.

[0204] In yet another embodiment, the hollow glass microspheres are present in an amount less than 5.9% by weight of the composition, such as less than 5.5% by weight, for example in the range of 0.1% to 5.0% by weight of the composition, 0.2% to 4.5% by weight, 0.5% to 4.0% by weight or 1.0% to 3.0% by weight.

[0205] Currently, in a preferred embodiment, the hollow glass microspheres are not added to the remaining components until after any final grinding.

[0206] Conductive pigments

[0207] The conductive pigment included in the coating composition of the present invention can be selected from graphite, carbon black, aluminum pigment, black iron oxide, antimony-doped tin oxide, indium tin oxide, mica coated with antimony-doped tin oxide, carbon nanotubes, carbon fiber, graphene, and any mixture thereof. In one embodiment, the conductive pigment is selected from graphite, carbon black, aluminum pigment, antimony-doped tin oxide, carbon nanotubes, carbon black, and any mixture thereof. In another embodiment, the conductive pigment is selected from graphite, carbon black, carbon nanotubes, and any mixture thereof. In another embodiment, the conductive pigment is graphite. In yet another embodiment, the conductive pigment is carbon black.

[0208] In the context of the present invention, when referring to "graphite", the term is used in the sense that it can still be considered as graphite by a skilled person by itself, without being incorporated into other materials, in particular zinc, by chemical bonds or the like.

[0209] In the coating compositions of the present invention, in one embodiment, the conductive pigment (such as graphite or carbon black, with graphite being present present in an amount of about 0.5% to 5.0% by solids volume of the coating composition, such as about 0.5% to 4.0% by solids volume, for example about 1.0% to 3.0% by solids volume, more particularly about 1.5% to 2.5% by solids volume.

[0210] In yet another embodiment, the coating composition of the present invention comprises graphite in an amount less than 4% by weight of the total composition, such as from about 0.1% to 3.8% by weight of the total composition, for example 0.5% to 3.5% by weight of the total composition.

[0211] The conductive pigments included in the present invention can be directly obtained from commercial channels.

[0212] Examples of suitable conductive pigments are:

[0213] Graphit AF96 / 97GraphitwerkKropfmühlAG - Germany (graphite)

[0214] Cond 8 / 96, Graphite Tyn,spol,sro - Czech Republic (micronized graphite)

[0215] DonaCarbo S-241, Osaka Gas Chemicals Co, Ltd Japan (Carbon Nano)

[0216] Minatec 40 cm, Merck KGaA - Germany (mica coated with antimony-doped tin oxide)

[0217] Raven 1000 from Columbian Carbon-USA (carbon black)

[0218] Carbon black Powercarbon 4300F, from Yongfeng Chemicals - China

[0219] Lamp Black 103, from Degussa AG - Germany (carbon black)

[0220] Special Black 1000, from Orion Engineered Carbons GmbH - Germany (carbon black)

[0221] Other components

[0222] The paint composition may comprise a plasticizer. Examples of plasticizers are hydrocarbon resins, phthalates and benzyl alcohol. In one embodiment, the paint composition comprises a hydrocarbon resin as a plasticizer.

[0223] The paint composition may contain other paint ingredients as will be apparent to one skilled in the art. Examples of such paint ingredients are non-conductive pigments such as TiO2, yellow or red iron oxide, cobalt blue, bismuth vanadate, and organic pigments; fillers such as Al / K / Na silicates (e.g., Silicato MN / SA 15 12 / 2009. Minerals IDerivats SA, Spain), talc, mica, and BaSO4; additives such as wetting agents, dispersants, scavengers, rheological agents, thickeners, defoamers, and thixotropic agents such as bentonite.

[0224] In the paint composition, the total amount of filler and non-conductive pigment may be in the range of 0%-50% by solid volume of the mixed paint composition, such as 0%-40%, 0%-30%, or 0%-25%. In addition, the total amount of filler and non-conductive pigment may be in the range of 5%-40% by solid volume, such as in the range of 10%-35% by solid volume.

[0225] In the paint composition, the total amount of additives may be in the range of 0% to 10%, such as 0.1% to 8%, by solids volume of the mixed paint composition.

[0226] In one embodiment, the coating composition of the present invention comprises less than 10% by weight of a filler, modified CaSiO3, also known as "Wollastonite."

[0227] In another embodiment, the paint composition comprises one or more additives selected from wetting agents and dispersants. Wetting agents and dispersants help to obtain a uniform dispersion of the particulate zinc material. Examples of suitable wetting agents and dispersants are:

[0228] Cargill Lecikote 20, from Cargill Foods (Belgium)

[0229] Lipotin 100, from Degussa Texturant Systems (Germany)

[0230] Nuosperse 657, from Elementis Specialities (Netherlands)

[0231] Anti Terra U, from BYK Chemie (Germany)

[0232] Disperbyk164, from BYK Chemie (Germany)

[0233] Anti Terra 204, from BYKChemie (Germany)

[0234] The paint composition may include an epoxy resin accelerator. Examples include substituted phenols such as 2,4,6-tris(dimethylaminomethyl)phenol, p-tert-butylphenol, nonylphenol, and the like, or salicylic acid. Examples include Ancamine K54 from Air Products Plc. (UK). The epoxy resin accelerator may be included in an amount of 0% to 7% by volume of solids, such as about 0.5% to 6% by volume of solids, for example about 1% to 5% by volume of solids, and more particularly about 2% to 4% by volume of solids.

[0235] Examples of suitable epoxy resin modifiers include, for example, oils, oil derivatives, modified oils such as linseed oil and its derivatives, castor oil and its derivatives, soybean oil and its derivatives.

[0236] The paint composition may also include a reactive epoxy resin diluent, such as a diluent from the class of monofunctional glycidyl ethers of aliphatic, cycloaliphatic, or aromatic compounds. Examples include Cardolite NC 513 from Cardanol Chemicals (US), Araldite DY-E / BD from Huntsman Advanced Materials (Germany), and Cardura E10P from Momentive (Netherlands). The epoxy resin diluent may be included in an amount of 0% to 9% by solids volume, such as about 2.5% to 8% by solids volume, for example about 3% to 7% by solids volume, and more particularly about 4% to 6% by solids volume.

[0237] The paint composition may also contain an epoxy resin plasticizer.

[0238] Paint compositions typically contain one or more solvents. Examples of solvents include water; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, or benzyl alcohol; alcohol / water mixtures such as ethanol / water mixtures; aliphatic, alicyclic, and aromatic hydrocarbons such as white spirit, cyclohexane, toluene, xylene, and naphtha solvent; ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, methyl isoamyl ketone, diacetone alcohol, and cyclohexanone; ethers, alcohols such as 2-butoxyethanol, propylene glycol monomethyl ether, and butyl diglycol; esters such as methoxypropyl acetate, n-butyl acetate, and 2-ethoxyethyl acetate; and mixtures thereof.

[0239] Depending on the application technology, it is ideal that the paint contains one or more solvents such that the solid volume ratio (SVR - ratio of the volume of the solid components to the total volume) - also called SV% - is in the range of 30-100%, such as 50-100%, in particular 55-100% for example 60-100%.

[0240] SVR is determined according to ISO 3233 or ASTM D 2697 with the following modification: drying is carried out at 20°C and 60% relative humidity for 7 days instead of drying at a higher temperature.

[0241] Kit of parts

[0242] As mentioned above, the epoxy resin base or other adhesive systems included in the coating composition of the present invention can comprise one or more curing agents. It will be appreciated by the technician that curing agent can advantageously be mixed with the remaining components of the adhesive system such as the epoxy resin in situ before use. The remaining components of the adhesive system are commonly referred to as "base component". In the context of the present invention, term "base component" means the component of the adhesive system except one or more curing agents.

[0243] Thus, another aspect of the present invention relates to a kit comprising a coating composition as defined herein, said kit comprising two or more containers, wherein one container comprises one or more curing agents and another container comprises a base component.

[0244] The components of the coating composition of the present invention as defined herein, other than the binder system and the curing agent, may be contained in either of the two containers of the kit, or may be contained in one or more additional containers. Typically, the components are present in the container containing the base component. Thus, in one embodiment, the portion of the coating composition of the present invention other than the curing agent is contained in the container containing the base component.

[0245] In a particular embodiment of the kit according to the invention, the polysiloxane-modified binder system comprises an epoxy resin part and an amino-functional polysiloxane and polysiloxane (modified) binder part, which are stored in two separate containers and mixed immediately before use. Thus, in one embodiment, the conductive pigment and hollow glass microspheres are added to the epoxy resin part, while the zinc particles are added to the part comprising the polysiloxane resin.

[0246] Specific implementation plan

[0247] For each of components a), b), c), and d) of the inventive paint compositions disclosed herein, several specific embodiments have been disclosed. Combinations of each described specific embodiment of component a) with each described specific embodiment of component b), each described specific embodiment of component c), and each described specific embodiment of component d) are contemplated.

[0248] More specifically, one embodiment of the present invention relates to a coating composition comprising:

[0249] a) epoxy resin based adhesive systems,

[0250] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0251] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0252] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0253] Another embodiment of the present invention is directed to a coating composition comprising:

[0254] a) epoxy resin based adhesive systems,

[0255] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0256] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0257] d) Graphite.

[0258] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0259] a) epoxy resin based adhesive systems,

[0260] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0261] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0262] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0263] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0264] a) epoxy resin based adhesive systems,

[0265] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0266] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0267] d) Graphite.

[0268] Another embodiment of the present invention is directed to a coating composition comprising:

[0269] a) epoxy resin based adhesive systems,

[0270] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0271] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0272] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0273] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0274] a) epoxy resin based adhesive systems,

[0275] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0276] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0277] d) Graphite.

[0278] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0279] a) epoxy resin based adhesive systems,

[0280] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0281] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0282] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0283] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0284] a) epoxy resin based adhesive systems,

[0285] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0286] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0287] d) Graphite.

[0288] Specific embodiments may also include a polysiloxane-based binder system. Thus, one embodiment of the present invention relates to a coating composition comprising:

[0289] a) polysiloxane-based adhesive systems,

[0290] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0291] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0292] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0293] Another embodiment of the present invention is directed to a coating composition comprising:

[0294] a) polysiloxane-based adhesive systems,

[0295] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0296] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0297] d) Graphite.

[0298] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0299] a) polysiloxane-based adhesive systems,

[0300] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0301] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0302] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0303] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0304] a) a polysiloxane-based adhesive system,

[0305] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0306] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0307] d) Graphite.

[0308] Another embodiment of the present invention is directed to a coating composition comprising:

[0309] a) a polysiloxane-based adhesive system,

[0310] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0311] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0312] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0313] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0314] a) a polysiloxane-based adhesive system,

[0315] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0316] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0317] d) Graphite.

[0318] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0319] a) a polysiloxane-based adhesive system,

[0320] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0321] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0322] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0323] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0324] a) polysiloxane-based adhesive systems,

[0325] b) Zinc particles, whose D50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0326] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 120 μm, and

[0327] d) Graphite.

[0328] Specific embodiments may also include a polyurethane-based adhesive system. Thus, one embodiment of the present invention relates to a coating composition comprising:

[0329] a) polyurethane-based adhesive systems,

[0330] b) Zinc particles, whose D 50 less than 20 μm are present in an amount of about 10% to 55% by solid volume,

[0331] c) uncoated hollow glass microspheres present in an amount of about 10% to 30% by solid volume and 90% of which have a diameter of less than 50 μm, and

[0332] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0333] Another embodiment of the present invention is directed to a coating composition comprising:

[0334] a) polyurethane-based adhesive systems,

[0335] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0336] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 50 μm, and

[0337] d) Graphite.

[0338] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0339] a) polyurethane-based adhesive systems,

[0340] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0341] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 120 μm, and

[0342] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0343] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0344] a) polyurethane-based adhesive systems,

[0345] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 10% to 55% by solid volume,

[0346] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 120 μm, and

[0347] d) Graphite.

[0348] Another embodiment of the present invention is directed to a coating composition comprising:

[0349] a) polyurethane-based adhesive systems,

[0350] b) Zinc particles, whose D 50 less than 20 μm are present in an amount of about 18% to 40% by solid volume,

[0351] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 50 μm, and

[0352] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0353] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0354] a) polyurethane-based adhesive systems,

[0355] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0356] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 50 μm, and

[0357] d) Graphite.

[0358] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0359] a) polyurethane-based adhesive systems,

[0360] b) Zinc particles, whose D 50less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0361] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 120 μm, and

[0362] d) Conductive pigments selected from graphite, carbon black, carbon nanotubes and any mixtures thereof.

[0363] Yet another embodiment of the present invention is directed to a coating composition comprising:

[0364] a) polyurethane-based adhesive systems,

[0365] b) Zinc particles, whose D 50 less than 20 μm, present in an amount of about 18% to 40% by solid volume,

[0366] c) uncoated hollow glass microspheres present in an amount of about 0.2% to 4.5% by weight and 90% of which have a diameter of less than 120 μm, and

[0367] d) Graphite.

[0368] coating system

[0369] The term "applying" is used in its normal sense in the paint industry. Thus, "applying" is carried out by any conventional method, for example by a brush, by a roller, by airless spraying, by air spraying, by dipping, etc. The most commercially interesting way to "apply" a coating composition is by spraying. Spraying is achieved by means of conventional spraying equipment known to those skilled in the art. The coating is usually applied with a dry film thickness of 5 to 300 μm, such as 5 to 125 μm or 25 to 300 μm.

[0370] In a particular embodiment of the present invention, an exterior coating composition is subsequently applied to the zinc-containing coating. The exterior coating typically comprises a coating composition selected from the group consisting of epoxy-based coating compositions, polyurethane-based coating compositions, acrylic-based coating compositions, polyurea-based coating compositions, polysiloxane-based coating compositions, and fluoropolymer-based coating compositions. Furthermore, the exterior coating is typically applied at a dry film thickness of 30-300 μm, such as 30-200 μm or 35-300 μm.

[0371] In one particular variation, an intermediate coating composition is first applied to the zinc-containing coating, followed by application of the outer coating. The intermediate coating typically comprises a coating composition selected from the group consisting of epoxy-based coating compositions, acrylic-based coating compositions, and polyurethane-based coating compositions. Furthermore, the intermediate coating is typically applied at a dry film thickness of 50-200 μm. In one embodiment, a first epoxy-based coating according to the present invention is applied, followed by application of an outer coating comprising a polyurethane-based resin.

[0372] Thus, the present invention also provides a coated structure comprising a metal structure having a first coating of a zinc-containing coating composition as described herein applied to at least a portion of the metal structure at a dry film thickness of 5-100 μm or 5-300 μm, such as 25-300 μm; and an outer coating applied to the zinc-containing coating at a dry film thickness of 30-300 μm, such as 30-200 μm. Preferably, the outer coating of the coating composition is selected from epoxy-based coating compositions, polyurethane-based coating compositions, acrylic-based coating compositions, polyurea-based coating compositions, polysiloxane-based coating compositions, and fluoropolymer-based coating compositions.

[0373] In one of the interesting variants, an intermediate coating is applied to the zinc-containing coating at a dry film thickness of 50-200 μm before the application of the outer coating composition. Preferably, the intermediate coating has a coating composition selected from epoxy-based coating compositions, acrylic-based coating compositions and polyurethane-based coating compositions.

[0374] The structure is typically selected from fixed or floating offshore equipment, for example steel structural components used in the oil or gas industry such as oil rigs, bridges, vessels, refineries, petrochemical industry, power plants, storage tanks, cranes, windmills, civil structures such as airports, tachymeters and high-rise buildings.

[0375] The structure is a metal structure, in particular a steel structure.

[0376] Preparation of paint compositions

[0377] The paints can be prepared by any suitable technique commonly used in the art of paint production. Thus, the paints according to the present invention can be mixed using a high-speed disperser, a ball mill, a bead mill, a triple roller mill, or the like to mix the various ingredients together. The paints according to the present invention can be filtered using a bag filter, a patron filter, a wire mesh filter, a wedge-shaped wire mesh filter, a metal flowline filter, an EGLM turnoclean filter (from Cuno), a DELTA strainer (from Cuno), and a Jenag strainer (from Jenag), or by vibratory filtration.

[0378] Typically, the solid components of the paint composition are mixed and ground. However, the hollow glass microspheres are advantageously not included until after grinding has been performed. Thus, in one embodiment, the hollow glass microspheres are included in the paint composition of the present invention after any grinding of the remaining paint components. In yet another embodiment, the present invention includes a paint composition that can be obtained by including the hollow glass microspheres after any grinding of the remaining paint components.

[0379] The paint composition can be prepared from a single component paint or by mixing two or more components, such as two premixes, one premix containing one or more resins and one premix containing one or more curing agents, or from a three component system, where one premix contains one or more resins and one premix contains one or more curing agents and the third container contains zinc particles.

[0380] The hollow glass microspheres and the conductive pigment may be added together or separately to any component of a paint composition prepared from two or more components.

[0381] It will be understood that when reference is made to a paint composition this is to a mixed paint composition. Furthermore, all amounts referred to as % by volume solids of the paint will be understood to be % by volume solids of the mixed paint composition unless otherwise stated.

[0382] Example

[0383] Example 1

[0384] Preparation of test plates

[0385] Steel panels were coated with 1 x 70 μm of the paint to be tested. The panels (10 x 15 cm x 1.6 mm) consisted of cold-rolled mild steel with a surface profile equivalent to BN 9 (Rugotest No. 3) and sandblasted to Sa 3 (ISO 8501-1). After coating the samples, the panels were conditioned for 7 days at a temperature of 23 ± 2°C and a relative humidity of 50 ± 5%.

[0386] Salt spray test with neutral salt spray according to ISO 9227

[0387] This method is performed to evaluate the corrosion resistance of coating systems by reproducing the corrosion that occurs in an atmosphere containing salt spray or splash.

[0388] The operating condition of the salt spray test is a constant spray of 5% NaCl solution at 35°C.

[0389] After the exposure period, blistering and rusting were evaluated on both panels and around the scratch (a few mm from the center) according to ISO 4628-2 and ISO 4628-3, respectively. Cracking was evaluated according to ISO 4628-4.

[0390] Adhesion was evaluated according to ISO 4624 (pull-off test).

[0391] After removing the coating at the scratch by a suitable method (mechanical or chemical cleaning), the width of the corrosion at 9 points is measured. The rust creep M is calculated by the formula M=(CW) / 2, where C is the average of the nine width measurements and W is the original width of the scratch (0.5 mm).

[0392] Preparation of coating compositions Composition 1 was prepared in the following manner:

[0393] In a 2.5-liter jar, one or more epoxy resins, fillers, wetting agents, dispersants, scavengers, rheological agents, and thickeners, along with 60% solvent (xylene:n-butanol 3:1 by weight) were premixed at 1000 rpm for 15 minutes using a high-speed mixer equipped with an impeller disk (90 mm diameter). Zinc particles were then added and mixed at 2000 rpm for approximately 15 minutes. Microspheres and 30% of the solvent were added under slow stirring. The remaining 10% of the solvent was then added.

[0394] Composition 2 was prepared in the following manner:

[0395] Mix the polyaminoamide and reactive epoxy resin diluent with 50% solvent. After a minimum of 16 hours, premix the epoxy resin accelerator, filler, graphite, defoamer, and thixotropic agent in a 2.5-liter jar using a high-speed mixer equipped with a 90 mm diameter impeller at 1000 rpm for 15 minutes. Then, mix in the benzyl alcohol and the remaining 50% solvent.

[0396] Immediately before application, component 2 was added to component 1 and the paint composition was mixed into a homogeneous mixture.

[0397] Table 1 - Basic formula of epoxy resin based paint

[0398]

[0399] 1) Wetting / dispersing / clearing / rheological / thickening agents

[0400] Defoaming agent / thixotropic agent

[0401] 3)PVC: Pigment volume concentration. The ratio of the volume of pigment to the volume of total non-volatile materials result

[0402] Table 2: Results of rust creep M

[0403]

[0404] *Relative to rust creep of the composition according to the invention. The lower the relative rust creep, the better the performance.

[0405] Table 3: Results of rust creep M

[0406]

[0407] *Relative to rust creep of the composition according to the invention. The lower the relative rust creep, the better the performance.

[0408] As can be seen from Tables 2 and 3, the model paints A and E encompassed by the present invention exhibit significant improvements in rust creep relative to the comparative model paints B, C, D, F, and G.

[0409] Example 2

[0410] Preparation of test plates

[0411] The steel plate (75 x 150 cm x 10 mm) was sandblasted to Sa 2 with a surface profile equivalent to BN 9 (Rugotest No. 3) and coated with 1 x 80 μm of the paint to be tested. 1 After the samples were coated, the panels were conditioned for 7 days at a temperature of 23±2° C. and 50±5% relative humidity.

[0412] Salt spray test according to ISO 4628-3:2003 neutral salt spray

[0413] This method is performed to evaluate the corrosion resistance of coating systems by reproducing the corrosion that occurs in an atmosphere containing salt spray or splash.

[0414] The operating condition of the salt spray test is a constant spray of 5% NaCl solution at 35°C.

[0415] SST was assessed by ISO 4628-3:2003 for measuring oxidation stages on coated panels.

[0416] Preparation of coating compositions Composition 1 was prepared in the following manner:

[0417] In a 2-liter jar, premix the epoxy resin, extender pigment / filler, wetting agent and dispersant, rheological agent and thickener, defoamer, and graphite using a high-speed mixer equipped with an impeller disk (90 mm diameter) at 1500 rpm for 15 minutes. Add the microspheres and 10% of the solvent while slowly stirring at 600 rpm. Then add the remaining 90% of the solvent.

[0418] Composition 2 was prepared in the following manner:

[0419] The aminofunctional silicone resin and polysiloxane, defoamer, thixotropic agent, wetting agent, and dispersant were premixed in a 2-liter jar using a high-speed mixer equipped with an impeller disk (90 mm diameter) at 1200 rpm for 15 minutes. Zinc particles and 10% of the solvent were added and mixed at 2000 rpm for approximately 15 minutes. The remaining 90% of the solvent was then added.

[0420] When preparing the comparative model paints, the step of adding graphite and / or glass spheres was omitted.

[0421] Immediately before application, component 2 was added to component 1 and the paint composition was mixed into a homogeneous mixture.

[0422] Table 4 - Basic formula of polysiloxane-based paint

[0423]

[0424] 1) Wetting and Dispersing / Rheology and Thickening / Defoaming Agents

[0425] 2) Defoaming / thixotropic / wetting and dispersing agents

[0426] result

[0427] Table 5: Results of SST

[0428]

[0429] *SST results are evaluated on a vertical and horizontal scale, which is from R i 0 = Very good start to R i 5 = Very bad

[0430] Example 3

[0431] Testing according to ISO 20340

[0432] The panels were exposed according to ISO 20340, Procedure A: Standard Procedure for Low-Temperature Exposure (Thermal Shock)

[0433] The exposure cycle used in this program lasts for one full week (168 hours) and includes 72 hours of QUV, 72 hours of salt spray testing (SST), and 24 hours of thermal shock (-20°C).

[0434] QUV exposure was performed according to ISO 11507 accelerated weathering, which simulates deterioration caused by sunlight and water such as rain or dew by exposure to fluorescent ultraviolet (UV) light and condensation. QUV cycle: UV-light 4 hours at 60±3°C with a UVA-340 lamp and 4 hours at 50±3°C with condensation.

[0435] • SST exposure was according to ISO 7253, exposure at 35°C with a constant spray of 5% NaCl.

[0436] • Thermal shock exposure consisted of placing the plates in a -20 ± 2°C freezer.

[0437] Total exposure period: 25 cycles, equivalent to 4200 hours.

[0438] Before the panels were climatized, horizontal 2 mm wide scratches were given at a distance of 20 mm from the bottom and sides.

[0439] When the test is stopped, the paint film at the scratch is removed and the width of the rust is evaluated. After removing the paint by a suitable method, the width of the corrosion is measured at nine points (the midpoint of the scratch line and four other points on each side of the midpoint, with a spacing of 5 mm). The rust creep M is calculated by the formula M = (CW) / 2, where C is the average of the nine width measurements and W is the initial width of the scratch. Preparation of test panels for testing according to ISO 20340

[0440] The steel plates (7×15 cm×5 mm) used for the measurements were cold-rolled mild steel having a surface profile equivalent to BN 9 (Rugotest No. 3) and sandblasted to Sa3 (ISO 8501-1).

[0441] The complete coating system applied to the steel panels is shown below:

[0442] First coating: Model paint with a film thickness of 60 μm

[0443] Second coating: Intermediate epoxy coating Hempadur 45880 with a film thickness of 140 μm

[0444] • Third coating: Top coating polyurethane Hempathane 55610 with a film thickness of 80 μm.

[0445] Allow to dry overnight between coats.

[0446] After coating the samples, the panels were conditioned for 7 days at a temperature of 23±2° C. and 50±5% relative humidity.

[0447] Preparation of coating compositions

[0448] The first coat of model paint was prepared in the same manner as the model paint in Example 1.

[0449]

[0450] 1) Wetting and dispersing agents / thickeners / rheology modifiers

[0451] 2) PVC: Pigment Volume Concentration. The ratio of the volume of pigment to the volume of all non-volatile materials

[0452] result

[0453] Table 7: Results of rust creep M

[0454] Paint composition Rust creep SST* Model paint 1 100 Model Paint 2 97 Model Paint 3 134 Model Paint 4 159

[0455] *Rust creep relative to model paint 1 according to the invention. The lower the relative creep, the better the performance.

[0456] As can be seen from Table 7, Model Paints 1 and 2 comprised by the present invention show a significant improvement in rust creep compared to Comparative Model Paints 3 and 4.

[0457] This example shows that the compositions according to the invention provide improved corrosion inhibition even though the amount of zinc is lower than in the comparative compositions.

[0458] Example 4

[0459] Table 8 - Basic formulation for a polyurethane based one-component moisture curing paint. Components were mixed under vacuum.

[0460]

[0461] 1) Plasticizer / wetting / scavenger / rheology / thickener

[0462] Example 5

[0463] Preparation of coating compositions Composition 1 was prepared in the following manner:

[0464] In a 2-liter jar, premix the hydroxy-functional acrylic resin solution, wetting and dispersing agent, defoamer, thickener, filler, graphite, and 75% solvent using a high-speed mixer equipped with a 90 mm diameter impeller at 1200 rpm for 15 minutes. Zinc particles are then added and mixed at 2500 rpm for approximately 15 minutes. The catalyst dissolved in the solvent is added as a let-down while stirring. The microspheres and 5% solvent are added while stirring slowly at 600 rpm. The remaining 20% ​​solvent is then added.

[0465] Composition 2 was prepared in the following manner:

[0466] The polyfunctional aliphatic isocyanate resin and 70% of the solvent were premixed in a 5 liter jar using a high speed mixer equipped with an impeller disk (90 mm diameter) at 1000 rpm for 15 minutes. The remaining 30% of the solvent was mixed.

[0467] Immediately before application, component 2 was added to component 1 and the paint composition was mixed into a homogeneous mixture.

[0468] Table 9 - Basic formulations for polyurethane based two-component paints

[0469]

[0470] Example 6

[0471] Various types of hollow glass microspheres were tested according to Example 1. The true densities of the hollow glass microspheres were 0.2, 0.2, 0.3, 0.38, and 0.40 g / cc, respectively, all yielding qualitatively similar results. The following corresponds to the original claims of the parent application:

[0472] 1. A coating composition comprising:

[0473] a) an adhesive system selected from the group consisting of epoxy resin-based adhesive systems, polysiloxane-based adhesive systems, polyurethane-based adhesive systems, cyclized rubber-based adhesive systems and phenoxy resin-based adhesive systems,

[0474] b) zinc particles,

[0475] c) hollow glass microspheres, and

[0476] d) a conductive pigment selected from the group consisting of graphite, carbon black, aluminum pigment, black iron oxide, antimony-doped tin oxide, mica coated with antimony-doped tin oxide, indium tin oxide, carbon nanotubes, carbon black fibers, and any mixtures thereof.

[0477] 2. The coating composition according to item 1, wherein the conductive pigment is selected from carbon black, carbon nanotubes, graphite, and any mixture thereof.

[0478] 3. The coating composition according to item 2, wherein the conductive pigment is graphite.

[0479] 4. The coating composition according to item 2, wherein the conductive pigment is carbon black.

[0480] 5. The coating composition according to any one of the preceding items, wherein the binder system is an epoxy-based binder system, a polyurethane-based binder system or a polysiloxane-based binder system.

[0481] 6. The coating composition according to any of the preceding items, wherein the binder system is an epoxy resin-based binder system or a polysiloxane-based binder system.

[0482] 7. The coating composition according to any of the preceding items, wherein the binder system is an epoxy resin based binder system.

[0483] 8. The coating composition according to any of the preceding items, wherein the conductive pigment is present in an amount of about 0.5% to 5.0% by solid volume of the coating composition, such as about 0.5% to 4.0% by solid volume, preferably about 1.0% to 3.0% by solid volume, and most preferably about 1.5% to 2.5% by solid volume.

[0484] 9. The coating composition of any preceding item, wherein the conductive pigment is graphite, the graphite being present in an amount of less than 4% by weight of the total composition, such as from about 0.1% to 3.8% by weight of the total composition, for example from 0.5% to 3.5% by weight of the total composition.

[0485] 10. The coating composition of any preceding item, wherein the hollow glass microspheres are uncoated.

[0486] 11. The coating composition according to any one of the preceding items, wherein the composition further comprises a solvent.

[0487] 12. The coating composition of any preceding item, wherein the hollow glass microspheres are present in an amount of less than 5.9% by weight, such as less than 5.5% by weight, for example, 0.1% to 5.0% by weight, 0.2% to 4.5% by weight, 0.5% to 4.0% by weight, or 1.0% to 3.0% by weight of the composition.

[0488] 13. The coating composition of any one of items 1 to 11, wherein the hollow glass microspheres are present in an amount of about 10% to 30% by solid volume, such as 15% to 25% by solid volume, preferably 18% to 24% by solid volume.

[0489] 14. The coating composition of any preceding item, wherein the hollow glass microspheres have a true density of about 0.05 g / cc to 0.75 g / cc.

[0490] 15. The coating composition of any preceding item, comprising one or more curing agents.

[0491] 16. A kit comprising a coating composition as defined in item 15, said kit comprising two or more containers, wherein one container comprises one or more curing agents and another container comprises the remaining components of part a) as defined in any one of items 1 to 13.

[0492] 17. A kit according to item 16, wherein the components b) and c) as defined in item 1 are contained in the same container as the components of part a) other than the one or more curing agents, and wherein component d) is contained in the same container as the one or more curing agents.

[0493] 18. A coated structure comprising a metal structure having a coating of a coating composition as defined in any one of items 1 to 15 applied to at least a portion of the metal structure.

[0494] 19. A method of coating a metal structure comprising the step of applying to at least a portion of said metal structure a layer of a coating composition as defined in any one of items 1 to 15.

Claims

1. An anti-corrosion zinc primer coating composition comprising: a) an epoxy resin-based binder system, wherein the epoxy resin-based binder system is in the range of 30% to 50% by solid volume of the coating composition, wherein the epoxy resin-based binder system comprises one or more epoxy resins having an epoxy equivalent weight of 150-700 and one or more curing agents selected from compounds or polymers comprising at least two reactive hydrogen atoms attached to nitrogen, b) Zinc particles, whose D 50 less than 20 μm, present in an amount of 10% to 50% by solid volume of the coating composition, and having a zinc content of at least 90%, c) uncoated hollow glass microspheres, 50% of which have a diameter less than 70 μm, wherein the hollow glass microspheres are present in an amount of 10% to 30% by solids volume of the coating composition, and d) a conductive pigment selected from graphite, carbon black and mixtures thereof, present in an amount of 0.5% to 5.0% by solid volume of the coating composition, The composition further comprises a solvent.

2. The anti-corrosion zinc primer coating composition according to claim 1, wherein the conductive pigment is present in an amount of 0.5% to 4.0% by solid volume of the coating composition.

3. The anti-corrosion zinc primer coating composition according to claim 1, wherein the conductive pigment is present in an amount of 1.0% to 3.0% by solid volume of the coating composition.

4. The anti-corrosion zinc primer coating composition according to claim 1, wherein the zinc particles are present in an amount of 20% to 40% by solid volume.

5. The anti-corrosion zinc primer coating composition of claim 1, wherein the hollow glass microspheres are present in an amount less than 5.9% by weight of the coating composition.

6. The anti-corrosion zinc primer coating composition according to claim 1, wherein the hollow glass microspheres are present in the range of 0.5% to 4.0% by weight of the coating composition.

7. The anti-corrosion zinc primer coating composition according to claim 1, wherein the hollow glass microspheres are present in the range of 1.0% to 3.0% by weight of the coating composition.

8. The anti-corrosion zinc primer coating composition according to claim 1, wherein the hollow glass microspheres are present in an amount of 18% to 24% by solid volume of the coating composition.

9. The anti-corrosion zinc primer coating composition according to claim 1, wherein the hollow glass microspheres are present in an amount of 15% to 25% by solid volume of the coating composition.

10. The anti-corrosion zinc primer coating composition according to claim 1, wherein the average particle size of the hollow glass microspheres is such that 50% of the particles have a diameter less than 50 μm.

11. The anti-corrosion zinc primer coating composition according to claim 1, wherein the hollow glass microspheres have a true density of 0.05 g / cc to 0.75 g / cc.

12. The anti-corrosion zinc primer coating composition according to claim 1, wherein the epoxy resin-based binder system is solvent-based or water-based.

13. A kit comprising the anticorrosion zinc primer coating composition as defined in claim 1, the kit comprising two or more containers, wherein one container comprises the one or more curing agents and another container comprises the remaining components of part a) as defined in any one of claims 1 to 12.

14. The kit according to claim 13, wherein the components b) and c) as defined in claim 1 are contained in the same container as the components of part a) other than the one or more curing agents, and wherein component d) is contained in the same container as the one or more curing agents.

15. A coated structure comprising a metal structure having a coating of the anti-corrosion zinc primer coating composition defined in any one of claims 1 to 12 applied to at least a portion of the metal structure.

16. A method of coating a metal structure comprising the step of applying to at least a portion of the metal structure a layer of an anti-corrosion zinc primer coating composition as defined in any one of claims 1 to 12.

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