Composition

Abstract

The present invention relates to a binder system comprising: (i) Epoxy-based binders; (ii) trimethylolethane triglycidyl ether; (iii) a curing agent; and (iv) homopolymerization promoters; Here, the wt % of trimethylolethane triglycidyl ether, based on the total dry weight of the binder system, is higher than the wt % of the epoxy-based binder, based on the total dry weight of the binder system.

Description

[Technical field]

[0001] The present invention relates to a binder system comprising an epoxy-based binder (an epoxy-based binder), trimethylolethane triglycidyl ether, a hardener, and a homopolymerization accelerator; and to methods and kits for producing the binder system. The present invention also relates to coating compositions comprising the binder system; and to methods and kits for producing the coating compositions; and to containers comprising either the binder system or the coating composition. Furthermore, the present invention relates to methods for producing a coating on a surface; and to the coating itself. The use of trimethylolethane triglycidyl ether in the binder system forms another aspect of the present invention. [Background technology]

[0002] The interior of metal tanks used to store large volumes of liquid chemicals are typically coated with a chemically resistant coating to protect the underlying metal, such as tanks found on cargo ships, as well as tanks found on land, such as chemical production facilities where large volumes of chemicals are produced, and large manufacturing sites where large volumes of chemicals are required.

[0003] A chemically resistant coating serves two distinct functions: it protects the underlying metal (usually steel) from chemical attack (e.g. corrosion), and it protects the tank contents from contamination. To perform the latter function, it is important that the coating does not absorb chemicals from the liquids it comes in contact with; because absorbed chemicals would subsequently leach out and contaminate the tank contents.

[0004] The chemically resistant coating should also be easy to clean between different loads and easy to apply to locations that may include non-level surfaces and large surface areas, such as inside a tank.

[0005] Currently, tank liner coatings with high chemical resistance are typically made of novolac epoxy resins and resorcinol diglycidyl ether (RDGE). These coatings have been found to provide high resistance to chemical absorption. It is believed that the high chemical resistance is achieved due to the high crosslink density obtained by using a combination of RDGE and novolac epoxy resin. This type of coating is usually cured using a dual cure mechanism that includes both amine-epoxy cure and epoxy-homopolymerization. It is generally believed that the presence of a benzene ring in the RDGE improves its compatibility with novolac epoxy resins and is an important feature in providing a high performance chemically resistant coating. Summary of the Invention [Problem to be solved by the invention]

[0006] However, coatings made of novolac epoxy resins and resorcinol diglycidyl ether (RDGE) have major drawbacks. RDGE is considered a carcinogen based on animal studies. For example, Sigma-Aldrich states in its safety profile that RDGE is "confirmed to be carcinogenic by experimental carcinogenicity and tumorigenicity data. Toxic by intraperitoneal route. Moderate toxicity by ingestion. Mutagenicity data reported." In the "Carcinogenicity" section, it states that "Diglycidyl resorcinol ether is reasonably expected to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals." The suspected carcinogenicity of RDGE significantly complicates both the production and application of coating compositions containing it; because additional safety precautions must be taken to avoid exposure to it. Finally, its HSE profile may lead to a ban on its use. [Means for solving the problem]

[0007] Viewed from a first aspect, the present invention provides a binder system comprising: (i) Epoxy-based binders; (ii) trimethylolethane triglycidyl ether; (iii) a hardener; and (iv) homopolymerization promoters; The wt % of trimethylolethane triglycidyl ether, based on the total dry weight of the binder system, is higher than the wt % of the epoxy-based binder, based on the total dry weight of the binder system.

[0008] Viewed from a further aspect, the present invention provides a method for producing a binder system as defined herein above, comprising mixing: (i) Epoxy-based binders; (ii) trimethylolethane triglycidyl ether; (iii) a hardener; and (iv) Homopolymerization promoters.

[0009] Viewed from a further aspect, the present invention provides a kit for producing a binder system as defined herein, comprising: (a) a first container containing an epoxy-based binder and trimethylolethane triglycidyl ether; and (b) A second vessel containing a hardener and homopolymerization accelerator.

[0010] Viewed from a further aspect, the present invention provides a coating composition comprising a binder system as defined herein above.

[0011] Viewed from a further aspect, the present invention provides a container comprising a binder system as defined herein above or a coating composition as defined herein above.

[0012] Viewed from a further aspect, the present invention provides a method for producing a coating composition as defined herein above, comprising mixing: (i) a binder system as defined herein above; and (ii) One or more other ingredients.

[0013] Viewed from a further aspect, the present invention provides a method for providing a coating on a surface, preferably on a metal surface, said method comprising: (i) applying a composition as defined herein above; and (ii) curing the composition to form a coating on the surface.

[0014] Viewed from a further aspect, the present invention provides a coating obtainable by a process as defined herein above.

[0015] Viewed from a further aspect, the present invention provides a coating comprising a binder system as defined herein or a coating composition as defined herein.

[0016] Viewed from a further aspect, the present invention provides the use of a composition as defined herein above for forming a coating on at least one surface of a substrate or an article, preferably a tank.

[0017] Viewed from a further aspect, the present invention provides the use of a binder system as defined herein above for forming a coating composition.

[0018] Viewed from a further aspect, the present invention provides the use of trimethylolethane triglycidyl ether for forming a binder system as defined herein above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] definition

[0020] As used herein, the term "coating composition" refers to a composition that, when applied to a surface, forms a film or coating thereon.

[0021] As used herein, the term "binder" refers to a polymer that forms a continuous film when applied to a substrate surface, with the other components of the composition dispersed throughout the binder.

[0022] As used herein, the term "binder system" refers to a system that includes an epoxy-based binder, trimethylolethane triglycidyl ether, a curing agent, and a homopolymerization accelerator, as well as, for example, a silane, and a reactive diluent.

[0023] As used herein, the term "epoxy-based" refers to polymers or oligomers containing epoxy groups and / or modified epoxy groups. The term epoxy-based binder encompasses binders that have a traditional epoxy backbone, but in which the epoxy end groups are modified, such as with acrylic or methacrylic functional groups that can be cured with the same curing agents as the epoxy groups. In many cases, the epoxy resin will contain at least some epoxy groups. The term epoxy is used interchangeably with epoxide.

[0024] As used herein, the term "epoxy" refers to a three atom cyclic ether.

[0025] As used herein, the phrase "equivalent epoxy weight" or "EEW" refers to the number of epoxide equivalents in 1 kg of resin, as measured by ASTM D-1652.

[0026] As used herein, the term "curing agents" refers to compounds that, when mixed with a binder, such as an epoxy-based binder, create crosslinks in the polymer, thereby producing a cured coating or a hardened coating. Curing agents are sometimes also referred to as hardeners.

[0027] As used herein, the term homopolymerization accelerator refers to a compound that increases the rate of epoxy-epoxy homopolymerization during the curing reaction to cure or harden the coating.

[0028] As used herein, the term "weight percent (wt%)" when used in reference to an individual component of a composition, such as an epoxy-based resin, unless otherwise stated, refers to the actual weight of the component, i.e., the weight without the presence of volatile components.

[0029] As used herein, the term "weight percent (wt%)" when used in relation to a coating composition, unless otherwise specified, refers to weight relative to the total weight of the composition, i.e., weight including non-volatile and volatile components.

[0030] As used herein, the term "Volatile Organic Compounds" refers to compounds that have a boiling point below 250° C. at 101.3 kPa. This is the definition in EU Directive 2004 / 42 / CE.

[0031] As used herein, the term "solvent-free" refers to a composition that contains less than 10 g / L VOCs.

[0032] As used herein, unless otherwise specified, the term "molecular weight" refers to the weight average molecular weight (Mw), as determined by gel permeation chromatography.

[0033] Detailed Description of the Invention

[0034] The present invention relates to a binder system comprising: (i) Epoxy-based binders; (ii) trimethylolethane triglycidyl ether; (iii) a hardener; and (iv) homopolymerization promoters; The wt % of trimethylolethane triglycidyl ether, based on the total dry weight of the binder system, is higher than the wt % of the epoxy-based binder, based on the total dry weight of the binder system.

[0035] The binder system of the present invention produces a tightly cross-linked, dense, polymer network that minimizes chemical absorption. This means that the binder system can be advantageously used in coating compositions designed for tank interiors, such as cargo tanks on ships and product storage tanks on land. In contrast to binder systems known in the art that contain resorcinol diglycidyl ether (RDGE), the binder system of the present invention does not contain compounds that are suspected or known to be carcinogenic. Thus, the binder system of the present invention has a significantly improved HSE profile compared to RDGE binder systems, without compromising performance.

[0036] Epoxy Binder System

[0037] The epoxy-based binder system of the present invention comprises a combination of one or more epoxy-based binders, trimethylolethane triglycidyl ether, one or more curing agents, a homopolymerization accelerator, and optionally a silane.

[0038] Preferably, the system does not contain any reactive diluents in addition to trimethylolethane triglycidyl ether, the presence of additional reactive diluents may interfere with the crosslinking reaction, thus reducing the density of the polymer network.

[0039] Trimethylolethane Triglycidyl Ether

[0040] Trimethylolethane triglycidyl ether is a low viscosity epoxy compound represented by the following formula I. It has a molecular weight of 288.34 g / mol and a CAS number of 68460-21-9.

[0041] Formula I Trimethylolethane Triglycidyl Ether

[0042] [ka]

[0043] Trimethylolethane triglycidyl ether is commercially available from, for example, Sigma Aldrich and Huntsman.

[0044] The trimethylolethane triglycidyl ether is preferably present in an amount of from 50 to 90 wt % of the binder system, more preferably from 60 to 80 wt %, and even more preferably from 60 to 70 wt % of the total dry weight of the binder system.

[0045] In a preferred binder system of the present invention, trimethylolethane triglycidyl ether is present in an amount of 50 to 90 wt %, more preferably 70 to 87 wt %, and even more preferably 75 to 85 wt %, based on the total dry weight of (i) the epoxy binder and (ii) the trimethylolethane triglycidyl ether.

[0046] In a preferred binder system of the present invention, the weight ratio of trimethylolethane triglycidyl ether to epoxy-based binder is 1:1 to 100:1, more preferably 1.1:1 to 20:1, and even more preferably 2:1 to 10:1. In one preferred binder system, the weight ratio of trimethylolethane triglycidyl ether to epoxy-based binder is greater than 3:1, preferably greater than 4:1. The incorporation of a relatively large amount of trimethylolethane triglycidyl ether compared to the epoxy-based binder system is believed to be important in the ability of the binder system to produce a dense polymer network.

[0047] Trimethylolethane triglycidyl ether has no proven or suspected carcinogenicity concerns and is therefore a much safer alternative to using resorcinol diglycidyl ether (RDGE), which is traditionally used in high chemical resistance coatings.The preferred binder system of the present invention does not include RDGE.The further preferred binder system of the present invention does not include aromatic glycidyl ethers, such as triglycidyl-p-aminophenol or tris(4-hydroxyphenylmethane triglycidyl ether).

[0048] Trimethylolethane triglycidyl ether is an aliphatic diglycidyl ether, which generally has a relatively poor compatibility with aromatic epoxy resins, such as novolac epoxy resins, than aromatic diglycidyl ethers. The lack of compatibility causes problems with relatively low reactivity in epoxy-epoxy homopolymerization reactions, and as a result, it is difficult to obtain a highly crosslinked network. In the present invention, it has surprisingly been found that it is possible to replace RDGE with an aliphatic triglycidyl ether, specifically trimethylolethane triglycidyl ether, which has a significantly improved HSE profile compared to RDGE, while still obtaining high crosslink density and excellent chemical resistance.

[0049] Epoxy Binder

[0050] The epoxy-based binder is preferably selected from aromatic or aliphatic epoxy-based binders, which preferably contain more than one epoxy group per molecule. The epoxy groups may be in internal or terminal positions on the epoxy-based binder, or may be on cyclic structures incorporated within the epoxy-based binder. Preferably, the epoxy-based binder contains at least two epoxy groups, which may form a crosslinked network.

[0051] It should be understood that the epoxy-based binders of the present invention also include binders that have a traditional epoxy backbone, but in which the epoxy end groups have been modified with acrylic or methacrylic functional groups that can be cured with the same curing agents as the epoxy groups.

[0052] Suitable aliphatic epoxy-based binders include epoxy binders and modified epoxy binders selected from cycloaliphatic epoxies such as hydrogenated bisphenol A, hydrogenated bisphenol A novolac, hydrogenated bisphenol F novolac, and dicyclopentadiene-based binders, glycidyl ethers such as polyglycidyl ethers of polyhydric alcohols, epoxy-functional acrylic resins, or any combination thereof.

[0053] Suitable aromatic epoxy-based binders include epoxy binders and modified epoxy binders selected from bisphenol-type epoxy-based binders such as bisphenol A, bisphenol F, and bisphenol S, novolac-type epoxy-based binders such as phenol novolac-type binders (bisphenol A novolac, bisphenol F novolac, bisphenol S novolac), and cresol novolac-type binders, or any combination thereof.

[0054] In some preferred binder systems, the epoxy-based binder is an aromatic epoxy-based binder. Preferably, the aromatic epoxy-based binder is derived from the combination of a compound containing at least one epoxide functional group with an aromatic co-reactive material containing at least two hydroxyl groups.

[0055] Preferred epoxy-based binders are novolac, bisphenol A epoxy-based binders and bisphenol F epoxy-based binders, or bisphenol A / F epoxy-based binders.

[0056] Particularly preferred epoxy binders are novolac epoxy binders because they generally provide a relatively high crosslink density. Preferred novolac epoxy binders are bisphenol A novolac, bisphenol F novolac, bisphenol S novolac, and cresol novolac. Particularly preferred epoxy binders are bisphenol F novolac. Bisphenol F novolac is also generally described as epoxy phenol formaldehyde resin.

[0057] Novolac epoxy resins are well known in the art and their general structure is shown in Formula II below, where n is the number of repeat units and R is H or a substituent.

[0058] Formula II

[0059] [ka]

[0060] The epoxy binder may be a modified epoxy binder. Preferably, the epoxy binder is modified with fatty acid, polypropylene oxide and / or polyethylene oxide. The epoxy binder may also be modified with flexible components such as rubber (e.g., chloroprene and butadiene-acrylonitrile rubber), polysiloxane, polyester, polyamide, polyurethane, and / or poly(meth)acrylic.

[0061] The solids content in the epoxy based binder is preferably greater than 70 wt%, more preferably greater than 80 wt%, preferably greater than 90 wt%, most preferably greater than 99 wt%. In a further preferred binder system, the epoxy based binder is solvent-free.

[0062] Examples of suitable epoxy-based binders that are commercially available are: Novolac epoxy binders: DEN 425, DEN 431, and DEN 438 from Olin; - Bisphenol A epoxy binders: Epikote 828 from Hexion, Araldite GY 250 from Huntsman Advanced Materials, - Bisphenol F epoxy binders: Epikote 862 from Hexion, YDF-170 from Kukdo, GY285 from Huntsman, DE 354 from Dow, BFE-170 from CCP, or KF8100 from Kolon. - Mixture of Bisphenol A & Bisphenol F: DER 352 from Dow Chemicals, Epikote 235 from Hexion.

[0063] The epoxy-based binder may have an epoxy equivalent weight (EEW) value of 120 to 1000. An EEW of less than 500, for example 150 to 300, especially 150 to 250, is particularly preferred.

[0064] The viscosity of the epoxy binder, measured at 50° C. according to ASTM D-445, is preferably 15,000 to 70,000 mPa, and more preferably 20,000 to 60,000 mPa.

[0065] The epoxy binder is preferably present in an amount of 1 to 30 wt% of the binder system, for example 5 to 25 wt% of the binder system, based on the total dry weight of the binder system. More preferably, the epoxy binder is present in an amount of 7 to 20 wt%, particularly 8 to 18 wt%, and most particularly 10 to 15 wt%, based on the total dry weight of the binder system. When a blend of epoxy binders is used, these percentages refer to the total epoxy binder content, i.e. the respective wt% are added together.

[0066] Hardener

[0067] The binder system also includes at least one hardener. The hardener can be any hardener commonly known as a hardener for epoxy-based binder systems. Preferably, it is amine-based.

[0068] To obtain a crosslinked network, the curing agent must contain at least two "reactive" hydrogen atoms. "Reactive" hydrogen atoms refer to the hydrogen atoms that migrate from the nucleophile to the oxygen atom of the epoxide during the ring-opening reaction. The curing agent typically contains at least two curing reactive functional groups.

[0069] Examples of suitable curing agents are thiol curing agents, polythiol curing agents, amine curing agents, polyamine curing agents, amine-functional polyamides, and / or amino-functional polymeric curing agents. The curing agent may alternatively also include at least one amino-functional polysiloxane.

[0070] An example of a suitable polythiol curing agent is pentaerythriol tetramercaptopropionate. An example of a suitable commercially available polythiol curing agent is GABEPRO™ GPM800 from Gabriel performance materials.

[0071] One preferred binder system includes at least one amine-functional hardener. The hardener typically contains at least two amine groups. The amine groups can be primary or secondary.

[0072] Suitable curing agents, including amine or amino-functional polymers, are selected from aliphatic amines and polyamines (e.g., cycloaliphatic amines and polyamines), amine-functional polyamides, polyetheramines, polyimidazoles, polyoxyalkyleneamines (e.g., polyoxyalkylenediamines), alkyleneamines (e.g., alkylenediamines), aralkylamines, aromatic amines, Mannich bases (e.g., those commercially available as "phenalkamines"), polyamines containing benzylamine structures, amino-functional silicones, or silanes, including epoxy adducts and derivatives thereof.

[0073] In certain preferred binder systems, the amine functional hardeners have cyclic structures, including cycloaliphatic amines and modified products of cycloaliphatic amines, preferably polyamines, the term cyclic including cycloaliphatic, aromatic, and heterocyclic polyamines.

[0074] In one preferred binder system, the amine functional hardener is a polyamine hardener having one or more benzylamine structures. It is understood that a polyamine is defined as a compound having at least two repeating amine units. Preferably, the polyamine contains more than three amine groups.

[0075] In one preferred binder system, the benzylamine group contains only one amine group.

[0076] In one preferred binder system, the amine-functional curing agent may have a benzylated polyalkylene polyamine structure as described in WO 2017 / 147138. The benzylated polyalkylene polyamine structure may be further reacted with, for example, a Mannich base or an epoxy-functional compound to create an epoxy adduct.

[0077] The binder system of the present invention may also employ adducts of amine hardeners, which may be produced by reaction of an amine with a suitable reactive compound, such as an epoxy binder, an epoxy-functional reactive diluent, an acrylate, a maleate, a fumarate, a methacrylate, or an electrophilic vinyl compound, such as acrylonitrile.

[0078] In particularly preferred binder systems of the present invention, the hardener is a cycloaliphatic amine or polyamine.

[0079] Examples of suitable commercially available amine-functional curing agents are as follows: Ancamine 2609, Ancamine 2695, Ancamine 2738, Ancamine 260A, Ancamide 500, Ancamide 506, Ancamide 2386, Ancamine 2759, Ancamine 2760, Ancamine 2712M, Ancamine 1618, Ancamine 2165, Ancamine 2280, Ancamine 2432, Ancamine 2519, Ancamine 2802, Ancamine 2609w, Ancamine 2806, Ancamine 2049, Ancamine 2143, Ancamine 2264, Ancamine 2167 from Evonik, Epikure 3140 from Hexion, GX-483 from Kukdo Chemical, Admark AP5050 from Polycoats, MXDA, and Gaskamine 240 from Mitsubishi Gas Chemical Company, Inc., Aradur 42 BD, and Aradur 943 CH from Huntsman Advanced Materials.

[0080] In one particularly preferred binder system, the hardener is an aliphatic and / or cycloaliphatic polyamine, such as Ancamine hardener from Evonik.

[0081] It will be appreciated that the curing agent may be supplied neat or in a solvent, however, ideally the curing agent is solvent-free.

[0082] One or more hardeners may be used in combination. In some preferred binder systems, two or more hardeners may be used in combination.

[0083] The hardener should cure the epoxy-based binder at a temperature in the range of 0-50° C. It is preferred that the epoxy-based binder system cures at ambient temperature.

[0084] It is common to express the equivalent weight of a hardener in terms of "active hydrogen equivalents." The number of "active hydrogen equivalents" for one or more hardeners is the sum of the contributions from each of the one or more hardeners. The contribution from each of the one or more hardeners to the active hydrogen equivalent is defined as the number of grams of hardener divided by the active hydrogen equivalent of the hardener, with the active hydrogen equivalent of the hardener being determined as the number of grams of hardener that correspond to one mole of active hydrogen. For adducts that include epoxy resins, the contributions of the reactants prior to the adduct are used to determine the number of "active hydrogen equivalents" in the finished epoxy-based binder system.

[0085] It is also common to indicate the number of "epoxy equivalents" in an epoxy binder. The "epoxy equivalent" is the sum of the contribution from each of the one or more epoxy binders and any other components, including epoxies, such as silanes and reactive diluents. The contribution from each of the one or more epoxy binders to the epoxy equivalent is defined as the number of grams of epoxy binder divided by the epoxy equivalent of the epoxy binder, where the epoxy equivalent of the epoxy binder is determined as the number of grams of epoxy resin corresponding to 1 mole of epoxy groups. For adducts that include an epoxy binder, the contribution of the reactants prior to the adduct can be used to determine the number of "epoxy equivalents" in the epoxy binder system.

[0086] Preferably, the ratio of the total hydrogen equivalent of the curing agent to the total epoxy equivalent (ie, molar ratio) in the epoxy binder system of the present invention is within the range of 0.2 to 0.7, more preferably 0.3 to 0.5.

[0087] It will be understood that the hardener is shipped separately from the epoxy binder and is only mixed with the epoxy binder immediately prior to application. The mixing ratio of the compositions containing the epoxy binder and hardener is, of course, governed by the relative amounts of epoxy and active hydrogen present. Preferably, the mixing ratio (in wt%) is 1:1 to 200:1 of the first composition to the second composition, more preferably 5:1 to 15:1 of the first composition to the second composition, and even more preferably 10:1 of the first composition to the second composition. The hardener composition and the epoxy binder composition are mixed immediately prior to application to a substrate.

[0088] In preferred binder systems, the hardener may be present in an amount of from 1 to 20 wt%, for example from 5 to 15 wt%, based on the total dry weight of the binder system.

[0089] Accelerator

[0090] The binder system of the present invention is believed to cure via a so-called dual cure mechanism. This means that the binder system is believed to undergo curing by two complementary cure mechanisms. These are: (i) the reaction of the epoxy groups of the epoxy resin with the functional groups having active hydrogen in the curing agent; and (ii) the reaction between the epoxy groups of the binder system, i.e., the reaction between the epoxy groups of the epoxy binder and the epoxy groups of the trimethylolethane triglycidyl ether. The latter reaction is sometimes called homopolymerization or epoxy homopolymerization. It is believed that the dual cure mechanism occurs to produce a dense polymer network that can reduce the absorption of liquids when they are present in the coating.

[0091] Without wishing to be bound by theory, it is believed that the hardener, e.g., amine, present in the binder system is S n It is believed that the epoxide reacts with the epoxy groups present in the mixture in the initial curing reaction via a 2 reaction. In this reaction, the epoxide ring opens and a hydrogen atom is transferred from the hardener, e.g., an amine, to the oxygen atom of the epoxide group. The transferred hydrogen is called "active hydrogen". Epoxy homopolymerization is generally a relatively slow reaction, but can be accelerated by the presence of homopolymerization accelerators.

[0092] The homopolymerization accelerator may be selected from tertiary amines, alcohols, imidazoles, organic acids, phenols, sulfonic acids, organic phosphines, and salts. Optionally, a combination of two or more homopolymerization accelerators may be used. Imidazole is the preferred homopolymerization accelerator. Alternatively, the homopolymerization accelerator may be a phosphonium ionic liquid.

[0093] Examples of suitable tertiary amines are triethanolamine, dialkylaminoethanol, triethylenediamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, benzyldimethylamine, and 2,4,6-tris(dimethylaminomethyl)phenol. One particularly preferred homopolymerization accelerator is 2,4,6-tris(dimethylaminomethyl)phenol, such as Ancamine K54 from Evonik.

[0094] Examples of suitable alcohols are ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, benzyl alcohol, furfuryl alcohol, and other alkyl alcohols, propanediol, butanediol, glycerol, and other polyhydric alcohols, triethanolamine, triisopropanolamine, dimethylaminoethanol, and other β-hydroxy tertiary amines.

[0095] Examples of suitable organic acids are acetic acid, propanoic acid, butyric acid, lactic acid, phenylacetic acid, and other alkyl carboxylic acids, malonic acid, oxalic acid, maleic acid, fumaric acid, and other dibasic acids or their monoesters, benzoic acid, 4-t-butylbenzoic acid, salicylic acid, 3,5-dichlorosalicylic acid, 4-nitrobenzoic acid, and other aromatic acids.

[0096] Examples of suitable phenols are alkylphenols such as nonylphenol.

[0097] Examples of suitable sulfonic acids are methanesulfonic acid and other alkylsulfonic acids, p-toluenesulfonic acid, 4-dodecylbenzenesulfonic acid and other aromatic sulfonic acids, naphthalenedisulfonic acid, di-nonylnaphthalenedisulfonic acid, and other polyhydric sulfonic acids.

[0098] Examples of suitable organophosphines are tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine.

[0099] Examples of suitable salts are calcium nitrate, calcium naphthenate, ammonium thiocyanate, sodium thiocyanate, potassium thiocyanate, imidazolinium thiocyanate, lithium tetrafluoroborate, lithium bromide, lithium trifluoroacetate, calcium chloride, ytterbium triphthalate, lithium perchlorate, zinc triphthalate, lithium nitrate, in which the cation can be replaced by lithium, sodium or potassium.

[0100] An example of a suitable phosphonium ionic liquid is tributyl(ethyl)phosphonium diethylphosphate.

[0101] Preferably, the homopolymerization accelerator is a phosphonium ionic liquid or an imidazole.

[0102] Preferably, the homopolymerization accelerator is an imidazole. A preferred imidazole is of the formula:

[0103] [ka]

[0104] Here, R 1 is a hydrogen atom, a C1-C10 alkyl group, an aryl group, an arylalkyl group, or a cyanoethyl group; R 2 ~R 4 each independently represents a hydrogen atom, a nitro group, a halogen atom, a C1 to C20 alkyl group, a C1 to C20 alkyl group substituted with a hydroxy group, an aryl group, an arylalkyl group, or a C1 to C20 acyl group; and The dashed lines represent single or double bonds.

[0105] Representative examples of suitable imidazoles include imidazole, 2-ethyl-4-methylimidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, 2-undecylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and combinations thereof.

[0106] Preferred imidazoles include 1-methylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole.

[0107] Particularly preferred homopolymerization accelerators are combinations of imidazole and tertiary amines, such as imidazole and 2,4,6-tris(dimethylaminomethyl)phenol, which have been shown to produce dense polymer networks under mild cure conditions.

[0108] Particularly preferred homopolymerization accelerators are combinations of phosphonium ionic liquids and tertiary amines, such as phosphonium ionic liquids and 2,4,6-tris(dimethylaminomethyl)phenol, which have also been shown to produce dense polymer networks under mild cure conditions.

[0109] In the preferred binder system, the homopolymerization accelerator may be present in an amount of 0.1 to 10 wt%, for example 1 to 5 wt%, based on the total dry weight of the binder system.

[0110] Also, an accelerator can be used to accelerate the reaction between the epoxy group of the epoxy resin and the functional group of the curing agent having active hydrogen. It should be noted that the homopolymerization accelerators mentioned above also generally accelerate the reaction between the epoxy group of the epoxy resin and the functional group of the curing agent having active hydrogen.

[0111] (Meth)acrylic acid esters are also known to accelerate the curing reaction between the epoxy groups of an epoxy resin and the functional groups of a curing agent having active hydrogen.

[0112] Examples of suitable (meth)acrylic acid esters are those of the following formula:

[0113] [ka]

[0114] where R is H or Me; n is 2 to 5; and L represents the residue of a polyol, such as the residue of hexanediol, the residue of a saccharide or sugar alcohol, etc. Thus, at least two OH groups of the polyol carry the acrylate ester shown in the above formula.

[0115] L preferably contains only C, H and O atoms. The molecular weight of L is preferably low, for example below 1000 g / mol.

[0116] In the preferred binder system, the total amount of accelerator may be present in an amount of 0.1 to 10 wt%, for example 1 to 5 wt%, based on the total dry weight of the binder system.

[0117] Silane

[0118] The binder system of the present invention optionally includes at least one silane. When present, the silane is part of the binder system and reacts with other components of the binder system upon curing. The silane functions as an adhesion promoter.

[0119] Preferably, the silane is a functional silane, having functional groups capable of reacting with the binder system, such as amine and / or epoxy groups. The silanes used in the present invention are generally of low Mw, for example less than 400 g / mol. Suitable silanes are of the general formula (I) or (II): (I) YR (4-z) Six z where z is an integer from 1 to 3, (II) YR (3-y) R 1 Six y where y is an integer from 1 to 2, Each R is a hydrocarbyl group having 1 to 12 C atoms, optionally containing an ether or amino linker; R 1 is a hydrocarbyl group having 1 to 12 C atoms; each X independently represents a halogen group or an alkoxy group; and Y is a functional group attached to R that can react with the epoxy binder and / or hardener.

[0120] Preferably, Y is an isocyanate, epoxy, amino, hydroxy, carboxy, thiol, acrylate or methacrylate group, more preferably an epoxy, amino, acrylate or methacrylate group, most preferably an epoxy or amino group. It is particularly preferred that Y is an epoxy group. The Y group may be attached to any part of the chain R. It will be understood that when Y represents an epoxy group, then R has at least two carbon atoms to allow the formation of an epoxide ring system.

[0121] In some particularly preferred silanes, Y is an amino group or an epoxy group. The amino group is preferably NH2. Preferably, Y is an epoxy group.

[0122] When the Y group is an amino group capable of reacting with an epoxy-based binder, it is preferred if the silane, together with the hardener, is provided separately from the epoxy-based binder.

[0123] Each X independently represents a halogen or alkoxy group. It is particularly preferred that X is an alkoxy group, such as a C1-6 alkoxy group, in particular a methoxy or ethoxy group. It is also particularly preferred that there are two or three alkoxy groups. Thus, z is ideally 2 or 3, in particular 3.

[0124] The index y is preferably two.

[0125] R 1 is preferably C1-4 alkyl, such as methyl.

[0126] R is a hydrocarbyl group having up to 12 carbon atoms. By hydrocarbyl is meant a group containing only C and H atoms. It may contain an alkylene chain or a combination of an alkylene chain and a ring, such as a phenyl ring or a cyclohexyl ring. The term "optionally containing an ether or amino linker" means that the carbon chain may be interrupted in the chain by -O- or NH- groups, thereby forming, for example, silanes, such as [3-(2,3-epoxypropoxy)propyl]trimethoxysilane: H2COCHCH2OCH2CH2CH2Si(OCH3)3.

[0127] R is preferably an unsubstituted (with the express exception of Y) unbranched alkyl chain having 2 to 8 C atoms.

[0128] Thus, the preferred silane general formula is that of structure (III): (III) Y'-R'(4-z')SiX'z where z' is an integer from 2 to 3, R' is an unsubstituted, unbranched alkyl chain having 2 to 8 C atoms, which optionally contains an ether or amino linker, Y' is an amino or epoxy functional group attached to the R' group; and X' represents an alkoxy group.

[0129] Examples of such silanes are the many representative products manufactured by Degussa in Rheinfelden and sold under the trade name Dynasylan® D, Silquest® silanes manufactured by Momentive, and GENOSIL™ silanes manufactured by Wacker.

[0130] Specific examples include methacryloxypropyltrimethoxysilane (Dynasylan MEMO, Silquest A-174NT), 3-mercaptopropyltri(m)ethoxysilane (Dynasylan MTMO or 3201; Silquest A-189), 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO, Silquest A-187), tris(3-trimethoxysilylpropyl)isocyanurate (Silquest Y-11597), γ-mercaptopropyltrimethoxysilane (Silquest A-189), β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (Silquest A-186), γ-isocyanatopropyltrimethoxysilane (Silquest A-Link 35, Genosil GF40), (methacryloxymethyl)trimethoxysilane (Genosil XL 33), (isocyanatomethyl)trimethoxysilane (Genosil XL 43), aminopropyltrimethoxysilane (Dynasylan AMMO; Silquest Al 110), aminopropyltriethoxysilane (Dynasylan AMEO) or N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (Dynasylan DAMO, Silquest Al 120) or N-(2-aminoethyl)-3-aminopropyltriethoxysilane, triamino-functional trimethoxysilane (Silquest A-1130), bis(γ-trimethoxysilylpropyl)amine (Silquest Al 170), N-ethyl-γ-aminoisobutyltrimethoxysilane (Silquest A-Link 15), N-phenyl-γ-aminopropyltrimethoxysilane (Silquest Y-9669), 4-amino-3,3-dimethylbutyltrimethoxysilane (Silquest Yl 1637), (N-cyclohexylaminomethyl)triethoxysilane (Genosil XL 926), (N-phenylaminomethyl)trimethoxysilane (Genosil XL 973), Deolink Epoxy TE and Deolink Amino TE (DOG Deutsche Oelfabrik), and mixtures thereof.

[0131] Other specific silanes of interest include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(aminoethyl)-aminopropyltrimethoxysilane H2NCH2CH2NHCH2CH2Si(OCH3)3, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, (H2NCH2CH2NHCH2CH2SiCH3(OCH3)2), [3-(2,3-epoxypropoxy)propyl]triethoxysilane (H2COCHCH2OCH2CH2CH2Si(OCH2CH3)3), [3-(2,3-epoxypropoxy)propyl]trimethoxysilane (H2COCHCH2OCH2CH2Si(OCH3)3).

[0132] The use of the silane 3-glycidoxypropyltrimethoxysilane is particularly preferred. Mixtures of silanes may also be used.

[0133] The amount of silane present in the binder system can be 0.1-10 wt%, preferably 0.5-5 wt%, more preferably 1-3 wt%, based on the total dry weight of the binder system. When a blend of silanes is used, these percentages refer to the total silane content, i.e., the wt% of each are added together.

[0134] It will be appreciated that if the silane has a functional group capable of reacting with an epoxy-based binder, it will need to be stored separately from the epoxy-based binder in the kit used to form the coating composition.

[0135] Reactive Diluents

[0136] The binder system of the present invention is preferably free of reactive diluents, especially epoxy-functional reactive diluents.

[0137] Reactive diluents are different from epoxy binders. Generally, epoxy-functional reactive diluents are of low molecular weight, e.g., less than 500 g / mol. Usually, the viscosity of the reactive diluent is less than 100 cp (0.1 Pa·s), preferably less than 50 cP (0.05 Pa·s), preferably less than 35 cp (0.035 Pa·s). It is therefore liquid at 23°C and atmospheric pressure.

[0138] Typical examples of epoxy-functional reactive diluents are phenyl glycidyl ether, alkyl glycidyl ether (with 1 to 16 carbon atoms in the alkyl group), glycidyl ester of neodecanoic acid (R 1 R 2 R 3 C-COO-Gly, where R 1 R 2 R 3 is an alkyl group, for example, a C8 to C10 alkyl group, and Gly is a glycidyl group), olefin epoxide (CH3-(CH2)n-Gly, where n=11 to 13, and Gly is a glycidyl group), 1,4-butanediol diglycidyl ether (Gly-O-(CH2)4-O-Gly), 1,6-hexanediol diglycidyl ether (Gly-O-(CH2)6-O-Gly), neopentyl glycol diglycidyl ether (Gly-O-CH2-C(CH3)2-CH2-O-Gly ), trimethylolpropane triglycidyl ether (CH3-CH2-C(CH2-O-Gly)3), and C1-20-alkylphenyl glycidyl ethers (preferably C1-5 alkylphenyl glycidyl ethers), such as methylphenyl glycidyl ether, ethylphenyl glycidyl ether, propylphenyl glycidyl ether, and para-tertiarybutylphenyl glycidyl ether (p-TBPGE), a reaction product of epichlorohydrin with oil obtained from cashew nut shells.

[0139] Preferably, the binder system does not include reactive diluents because, if present, they form part of the binder system during the curing process and react with other components of the binder system, which is believed to disrupt the dense polymer network that would otherwise be formed by the binder system of the present invention.

[0140] Other Binder System Components

[0141] Preferably, the binder system of the present invention does not include a co-binder.It is believed that the presence of a co-binder reduces the density of the polymer network and therefore increases the absorption capacity of the coating containing the binder.Examples of typical co-binders are saturated polyester resins, polyvinyl acetate, polyvinyl butyrate; copolymers of vinyl acetate and vinyl isobutyl ether; copolymers of vinyl chloride and vinyl isobutyl ether; styrene copolymers, such as styrene / butadiene copolymers; acrylic resins, polysiloxanes, hydroxy-acrylate copolymers, fatty acids, and cyclized rubbers.

[0142] Preferably, the binder system of the present invention does not contain uron-based hardener. Particularly preferably, the binder system of the present invention does not contain uron selected from 1,3-diphenylurea, benzylurea, 1,1-dimethyl-3-phenylurea, N-ethylurea, N-(2-chloro-4-pyridyl)-N'-phenylurea, N,N'-dibenzylurea, N-(4-chlorophenyl)N,N-dimethylurea, N-(4-chlorophenyl)n,n-dimethylurea, N-phenyl-N,N-dimethylurea, 2,4-toluenebisdimethylurea, 2,4-toluenebisdimethylurea, alicyclic bijuar, toluenebisdimethylurea, 4,4'methylenebis(phenyldimethylurea), N,N-dimethyl-N'-[3-(trifluoromethyl)phenyl]-urea, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and combinations thereof.

[0143] Preferably, the binder system of the present invention does not include hydrazide hardeners, such as aromatic hydrazides or aliphatic hydrazides. Particularly preferably, the binder system of the present invention does not include adipic dihydrazide, adipic dihydrazide, 3,4-diaminobenzhydrazide, succinic dihydrazide, 4-aminobenzoic hydrazide, (+)-biotinamide hexanoic hydrazide, oxalyl dihydrazide, maleic hydrazide, dodecanoic dihydrazide, isophthalic dihydrazide, 1,4-cyclohexyl dihydrazide, 4,4'-(propane-1,3-diylbisoxy)dibenzoic dihydrazide, terephthalic dihydrazide, isophthalic dihydrazide, and combinations thereof.

[0144] Preferably, the binder system of the present invention does not include polyphenol resins.

[0145] Coating Composition

[0146] The binder system of the present invention is preferably present in a coating composition. The coating composition may consist of the binder system as described hereinbefore. Alternatively, the coating composition may comprise further components. Preferred further components are described below.

[0147] Preferably, the coating composition comprises 20-80 wt% of the binder system, more preferably 30-70 wt% of the binder system, and even more preferably 40-60 wt% of the binder system, based on the total weight of the coating composition. Preferably, the coating composition comprises 20-80 wt% of the binder system, more preferably 30-70 wt% of the binder system, and even more preferably 40-60 wt% of the binder system, based on the total dry weight of the coating composition.

[0148] Preferably, the coating composition comprises 15-60 wt% trimethylolethane triglycidyl ether, more preferably 20-50 wt% trimethylolethane triglycidyl ether, and even more preferably 25-40 wt% trimethylolethane triglycidyl ether, based on the total weight of the coating composition. Preferably, the coating composition comprises 15-60 wt% trimethylolethane triglycidyl ether, more preferably 20-50 wt% trimethylolethane triglycidyl ether, and even more preferably 25-40 wt% trimethylolethane triglycidyl ether, based on the total dry weight of the coating composition.

[0149] Preferably, the coating composition comprises 1-30 wt% of the hardener, more preferably 2-15 wt% of the hardener, and even more preferably 3-10 wt% of the hardener, based on the total weight of the coating composition. Preferably, the coating composition comprises 1-30 wt% of the hardener, more preferably 2-15 wt% of the hardener, and even more preferably 3-10 wt% of the hardener, based on the total dry weight of the coating composition.

[0150] Preferably, the coating composition contains 0.1 to 10 wt% of the homopolymerization accelerator, more preferably 0.5 to 7 wt%, and even more preferably 1 to 5 wt%, based on the total weight of the coating composition. Preferably, the coating composition contains 0.1 to 10 wt% of the homopolymerization accelerator, more preferably 0.5 to 7 wt%, and even more preferably 1 to 5 wt%, based on the total dry weight of the coating composition.

[0151] Preferably, the coating composition comprises 0.1-10 wt% of the silane, more preferably 0.2-5 wt% of the silane, even more preferably 0.5-2.5 wt% of the silane, based on the total weight of the coating composition. Preferably, the coating composition comprises 0.1-10 wt% of the silane, more preferably 0.2-5 wt% of the silane, even more preferably 0.5-2.5 wt% of the silane, based on the total dry weight of the coating composition.

[0152] Preferably, the coating composition comprises 0-15 wt% reactive diluent, more preferably 0.1-10 wt% reactive diluent, even more preferably 0.5-5 wt% reactive diluent, based on the total weight of the coating composition. Preferably, the coating composition comprises 0-15 wt% reactive diluent, more preferably 0.5-10 wt% reactive diluent, even more preferably 1-5 wt% reactive diluent, based on the total dry weight of the coating composition.

[0153] Preferably, the coating composition comprises 0 to 5 wt % of solvent, more preferably 0 to 4 wt % of solvent, and even more preferably 0 to 2.5 wt % of solvent.

[0154] Filler

[0155] The coating composition of the present invention may include one or more fillers.A wide variety of fillers may be used.Examples of suitable fillers are barium sulfate, titanium dioxide, zinc oxide, aluminum oxide, carbonates, borates, silica, silicates such as feldspar, kaolin, and wollastonite, heavy metal oxides such as cerium oxide, lanthanum oxide, and zirconium oxide, mica, diatomaceous earth, and bentonite clay.

[0156] Particularly preferred fillers are titanium dioxide, aluminum dioxide, feldspar, kaolin, wollastonite, and barium sulfate. It is preferred that more than one type of filler is used in the coating composition of the present invention.

[0157] Flake-like fillers having a lamellar or plate-like structure, such as mica, talc, and glass flakes, may be used in the coating compositions of the present invention.

[0158] Preferably, the aspect ratio of the flake filler is greater than 3, such as greater than 6, preferably greater than 10. The aspect ratio can be measured, for example, by using a scanning electron microscope (SEM).

[0159] The thickness of the flake filler is preferably 0.1 to 15 μm, more preferably 0.5 to 10 μm, and further preferably 1.0 to 8.0 μm. The thickness of the flake filler can be measured, for example, by a scanning electron microscope (SEM).

[0160] The particle size and thickness of the flake fillers referred to herein is the size of the flakes as they are added to the composition, prior to any extrusion or grinding process.

[0161] Preferred flake fillers are talc, mica, and glass flake.

[0162] Spherical filler particles may also be used in the coating compositions of the present invention.

[0163] The spherical filler particles can be organic or inorganic spherical filler particles. Preferably, the spherical filler particles are inorganic spherical filler particles.

[0164] The spherical filler particles can be hollow or non-hollow. In some preferred compositions, the spherical filler particles are hollow. This means that the particles have a void or cavity in their center. This void or cavity is filled with a gas, preferably air.

[0165] Suitable hollow inorganic spherical filler particles are commercially available. Examples of suitable commercially available hollow inorganic spherical filler particles include Fillite Cenosphere, Poraver (expanded glass), Thermospheres, Omega spheres (available from, for example, 3M, Trelleborg, Potters, SMC minerals, etc.), and Hollolite.

[0166] Preferably, the hollow inorganic spherical filler particles have a low density, for example the density of the hollow inorganic spherical filler particles is between 0.1 and 1 gcm 3, more preferably 0.2 to 0.8 gcm 3 , and more preferably 0.25 to 0.5 gcm 3 For example, it may be as specified in a technical specification provided by a supplier.

[0167] The inorganic spherical filler particles may comprise, and more preferably consist of, glass, ceramic, calcium aluminium cement, or metal oxides, preferably glass.

[0168] Optionally, the inorganic spherical filler particles may be surface treated.

[0169] Preferably, the inorganic spherical filler particulates have a Z-average diameter, as determined by ISO 22412:2017 using a Malvern Mastersizer 2000, of 1.0 to 100 μm, more preferably 1.0 to 80 μm, and even more preferably 10 to 50 μm.

[0170] The filler is preferably present in the coating composition of the present invention in an amount of 0-70 wt%, preferably 10-60 wt%, more preferably 20-50 wt%, based on the total weight of the coating composition. The filler is preferably present in the coating composition of the present invention in an amount of 0-70 wt%, preferably 10-60 wt%, more preferably 20-50 wt%, based on the total dry weight of the coating composition.

[0171] Additives

[0172] The coating composition of the present invention optionally contains a wide variety of additives. Examples of additives that may be optionally present in the coating composition include color pigments, rheology modifiers (anti-sagging / anti-settling agents), thickeners, rust inhibitors, drying agents, dispersants, surface modifiers, plasticizers, and adhesion promoters. Any conventional additives may be present.

[0173] The additional additives are preferably present in the coating composition in an amount of 0 to 50 wt%, more preferably 0.1 to 30 wt%, even more preferably 0.1 to 20 wt%, and especially preferably 0.5 to 10 wt%, based on the total weight of the coating composition.

[0174] Examples of color pigments include titanium white, red iron oxide, yellow iron oxide, black iron oxide, carbon black, and organic color pigments.

[0175] As rheology modifiers, thixotropic agents may be employed, such as polyamide wax, diatomaceous earth, polyethylene wax, fumed silica, or bentonite-based thixotropic agents, etc. Examples of such anti-sagging / anti-settling agents include either Crayvallac Ultra or Crayvallac LV from Arkema, either Thixatrol ST or Thixatrol Max from Elementis, Disparlon 6650 from Kusumoto Chemicals, and Celite from Imerys.

[0176] It may also be useful to include anti-corrosion components in the coating composition. Examples of suitable anti-rust components are zinc phosphate, zinc oxide, zinc dust, zinc flake, and aluminum flake.

[0177] composition

[0178] A preferred coating composition of the present invention comprises: (i) 20-80 wt %, preferably 40-60 wt %, of an epoxy-based binder; (ii) 15 to 60 wt %, preferably 25 to 40 wt %, of trimethylolethane triglycidyl ether; (iii) 1 to 30 wt %, preferably 3 to 10 wt %, of a hardener; and (iv) 0.1 to 10 wt %, preferably 1 to 5 wt %, of a homopolymerization accelerator; Here, wt % is based on the total dry weight of the composition.

[0179] Particularly preferred coating compositions of the present invention comprise: (i) 20-80 wt %, preferably 40-60 wt %, of an epoxy-based binder; (ii) 15 to 60 wt %, preferably 25 to 40 wt %, of trimethylolethane triglycidyl ether; (iii) 1-30 wt %, preferably 3-10 wt %, of a hardener; (iv) 0.1 to 10 wt %, preferably 1 to 5 wt %, of a homopolymerization accelerator; and (v) 0.1 to 10 wt %, preferably 0.5 to 2.5 wt %, of a silane; Here, wt % is based on the total dry weight of the composition.

[0180] Further particularly preferred coating compositions of the present invention contain from 0.05 to 5 wt %, preferably from 0.1 to 2 wt %, of a thixotropic agent, where wt % is based on the total dry weight of the composition.

[0181] Further particularly preferred coating compositions of the present invention contain from 1 to 10 wt %, preferably from 2 to 6 wt %, of a colour pigment, where wt % is based on the total dry weight of the composition.

[0182] Further particularly preferred coating compositions of the present invention contain 0 to 70 wt %, preferably 5 to 50 wt %, of filler, where wt % is based on the total dry weight of the composition.

[0183] Preferred coating compositions of the invention have a solids content of at least 98 wt%, more preferably at least 99 wt%. Particularly preferred is a solids content of 100 wt% of the coating composition of the invention.

[0184] Preferred coating compositions of the present invention contain very low solvent content, such as less than 5.0 wt% solvent, particularly less than 2.0 wt% solvent, more particularly less than 1.0 wt% solvent, such as 0.5 wt% or less solvent. Ideally, the coating composition is substantially solvent-free (e.g., solvent-free).

[0185] High solids volume and low solvent content lead to relatively low VOC content. The VOC content of the coating composition is preferably less than 250g / L, more preferably less than 100g / L, most preferably less than 50g / L, for example, the VOC content can be 25g / L or less, for example 10g / L or less. This means that the coating composition is substantially free of VOC.

[0186] The pot life of the coating composition of the present invention is preferably at least 1 hour, such as 1 to 3 hours, such as 1.5 to 2.5 hours. By pot life is meant the time after mixing the first and second components that the coating composition is ready to be applied to a substrate. A pot life of less than 30 minutes is commercially unfeasible, considering the time it takes to coat a large object.

[0187] Preferred coating compositions of the present invention are sprayable. Particularly preferred coating compositions of the present invention are thixotropic. Thus, the coating composition flows when shear is applied in the spraying equipment, but does not flow when applied to a surface.

[0188] The coating composition of the present invention adheres well to both the substrate and the primer layer thereon, provides resistance to absorption and rapid hardening, and is also free of RDGE, which has an undesirable HSE profile.

[0189] Preferred coating compositions of the present invention provide coatings that are curable at ambient temperature. Particularly preferred coating compositions provide coatings that are curable at temperatures below 150° C., more preferably below 100° C., and even more preferably below 90° C., each at 50% RH.

[0190] Preferred coating compositions of the invention have a Tg, eg, as determined by the method described in the Examples, of at least 130°C, more preferably at least 140°C, and even more preferably at least 150°C.

[0191] More preferred coating compositions of the invention have a 1 day xylene absorption, eg, as determined by the method described in the Examples, of less than 0.5 wt.%, preferably less than 0.3 wt.%.

[0192] Further preferred coating compositions of the invention have a 1-day 1,2-dichloroethane (EDC) absorption of less than 1 wt%, preferably less than 0.5 wt%, e.g., 1-day 1,2-dichloroethane (EDC) absorption as determined by the method described in the Examples.

[0193] Containers and kits

[0194] The present invention also relates to a container comprising the binder system, or coating composition, as described herein above. Suitable containers include plastic bag-lined cardboard boxes and plastic bags (so-called "big bags").

[0195] Alternatively, each of the binder system and coating composition of the present invention may be provided in the form of a kit.

[0196] The binder system of the present invention is preferably formed from a combination of a first composition (A) and a second composition (B). To prevent premature curing, the binder system of the present invention is preferably provided in two parts: a first composition (A) containing an epoxy-based binder and trimethylolethane triglycidyl ether, and a second composition (B) containing a curing agent and a homopolymerization accelerator.

[0197] Similarly, the coating composition of the present invention is preferably formed from a combination of a first composition (A) and a second composition (B). To prevent premature curing, the coating composition of the present invention is preferably provided in two parts: a first composition (A) containing an epoxy binder and trimethylolethane triglycidyl ether, and a second composition (B) containing a curing agent and a homopolymerization accelerator. Other components of the coating composition may be present in either component (A) or (B), so long as any component present in component (A) does not react with any other component in component (A) and any component present in component (B) does not react with any other component in component (B).

[0198] Thus, kits for producing the binder systems and coating compositions of the present invention include: (i) a first container containing an epoxy-based binder and trimethylolethane triglycidyl ether; and (ii) A second vessel containing a curing agent and a homopolymerization accelerator.

[0199] Preferred kits further comprise a silane, particularly preferably in the first container.

[0200] Preferred kits further comprise a thixotropic agent, particularly preferably in the first container.

[0201] A preferred kit further comprises a colour pigment, particularly preferably in the first container.

[0202] A preferred kit further comprises a filler and / or extender, particularly preferably in the first container.

[0203] manufacturing

[0204] The present invention also relates to a process for producing a binder system and / or a coating composition as described hereinbefore, which comprises mixing: (i) Epoxy-based binders; (ii) trimethylolethane triglycidyl ether; (iii) a curing agent; and (iv) Homopolymerization promoters.

[0205] In a preferred method of the present invention, the binder and trimethylolethane triglycidyl ether are premixed and the hardener and homopolymerization accelerator are premixed separately, and the two resulting mixtures are then combined and mixed.

[0206] When forming a coating composition containing further components, these components are preferably premixed with the binder and trimethylolethane triglycidyl ether. If present, the silane is preferably premixed with the binder and trimethylolethane triglycidyl ether. If present, the thixotropic agent is preferably premixed with the binder and trimethylolethane triglycidyl ether. If present, the color pigment is preferably premixed with the binder and trimethylolethane triglycidyl ether. If present, the filler / extender is preferably premixed with the binder and trimethylolethane triglycidyl ether.

[0207] Any conventional mixing equipment may be used. For example, the various ingredients may be mixed together using a high speed disperser, a ball mill, a pearl mill, a three-roll mill, an in-line mixer, or the like.

[0208] Conveniently, the binder system and / or coating composition are supplied as a kit as previously described herein, it being understood that the relative amounts of each component in any part of the kit will be determined by the final wt% values ​​and relative mix ratios in the coating composition.

[0209] Applications for Surfaces, Coatings, and Coating Systems

[0210] The present invention also relates to a method for coating a surface, preferably a metal surface, said method comprising: (i) applying a composition as previously described herein; and (ii) curing the composition to form a coating on the surface.

[0211] Optionally, the surface is pretreated before applying the coating composition of the present invention. Optionally, the surface is coated with a primer composition before applying the coating composition of the present invention. Thus, the coating composition of the present invention can be part of a coating system. However, it is preferred that the coating composition is applied directly onto the surface.

[0212] The coating composition of the present invention can be applied to the substrate by any conventional coating method, such as spraying, rolling, dipping, etc. Preferably, the coating composition is applied by spraying, more preferably by airless spraying. Spraying is preferred because it allows large surface areas to be coated in a uniform manner. Furthermore, spraying can be used to coat non-horizontal surfaces. Preferably, the substrate is metal, especially steel.

[0213] Preferably, the coating composition of the present invention is applied as a single layer. Optionally, the layer can be applied in a single step or in multiple steps with drying and curing between each step.

[0214] The present invention also relates to a coating comprising a coating composition as hereinbefore described. Optionally, the coating is applied in several steps, where a first layer of the coating is applied, dried and cured, and then a subsequent layer of the coating is applied. Preferably, the number of application steps is minimized. Preferably, the layer of the coating applied in a single step is 50-1000 mm, more preferably 100-500 mm.

[0215] The coating compositions of the present invention can be used to form single layer coatings or multi-layer coatings (ie, coating systems).

[0216] Hardener

[0217] Preferably, the coating of the present invention is cured. Thus, once a substrate is coated with the coating composition of the present invention, the coating is preferably cured. Preferably, the curing is performed in two stages. In the first stage, the curing is preferably performed at ambient temperature (i.e., 20°C). In the second stage, the curing is preferably performed at 50-100°C, more preferably 60-90°C, and even more preferably 70-85°C. The "high temperature cure" in the second stage is believed to promote the epoxy homopolymerization reaction, which is believed to be important in achieving a dense polymer network.

[0218] Substrates and articles

[0219] The present invention also relates to a substrate coated with a coating composition as described hereinbefore or a coating as described hereinbefore. The coating composition of the present invention may be applied to any substrate. Representative substrates include metal substrates (steel, galvanized steel, aluminum, copper), glass, ceramics, and polymeric materials (e.g., plastics). Preferred substrates are metal substrates. The coating of the present invention provides a protective coating, particularly a chemically resistant coating, on such substrates.

[0220] The type of metal substrate that is preferably coated with the coating of the present invention is one that comes into contact with chemicals, such as large volumes of liquid chemicals. Examples of metal substrates include storage tanks (e.g., cargo ships, product storage), process vessels, pressure vessels, reactor tanks, secondary containment vessels, containment dikes, dike walls, structures in chemically aggressive facilities, and areas at risk of exposure to serious chemical spills. Particularly preferred substrates are metal tanks, especially the inner surface of metal tanks, such as the inner surface of metal tanks on cargo ships or the inner surface of metal tanks in land-based product storage facilities.

[0221] The substrate may be partially or completely coated with the coating composition or coating of the present invention. However, preferably, all of the substrate is coated with the coating composition or coating of the present invention. In the case of a tank, preferably the interior wall is coated with the coating composition of the present invention.

[0222] Preferably, the coating has a total dry thickness of from 50 to 1000 mm, more preferably from 100 to 500 mm.

[0223] Preferred coatings of the invention have a Tg, for example as determined by the method described in the Examples, of at least 130°C, more preferably at least 140°C, and even more preferably at least 150°C.

[0224] More preferred coatings of the invention have a 1 day xylene absorption, for example as determined by the method described in the Examples, of less than 0.5 wt%, preferably less than 0.3 wt%.

[0225] More preferred coatings of the invention have a 1-day EDC absorption, eg, as determined by the method described in the Examples, of less than 1 wt%, preferably less than 0.5 wt%.

[0226] use

[0227] The present invention also provides the use of a composition as described hereinbefore for forming a coating on at least one surface of a substrate or article, preferably a tank, preferably said surface being a metal surface as described hereinbefore.

[0228] The present invention also provides the use of a binder system as described hereinbefore to form a coating composition.

[0229] The present invention also provides the use of trimethylolethane triglycidyl ether to form a binder system as hereinbefore described.

[0230] The invention will now be described with reference to the following non-limiting examples. EXAMPLES

[0231] material

[0232] The compounds and polymers used in the examples were all commercially available. The compounds and polymers used are summarized in the table below. EEW is the epoxy equivalent weight, AHEW is the amine hydrogen equivalent weight.

[0233] [Table 1]

[0234] Preparation of Coating Compositions Comprising the Binder System of the Present Invention

[0235] The components of the coating composition were mixed in the proportions shown in the table below, where the components of the composition are given in wt %.

[0236] The entire amount of component A was mixed in a dissolver. Component B was mixed by mechanically stirring (agitating) the liquid-only components.

[0237] Generation of test samples

[0238] For Tg determination by DMA: Test samples were prepared by mixing component A and component B and applying the mixture onto a Mylar® polyester sheet to allow easy removal of the loose coating film. The coating thickness (dry film) was in the range of 200-400 μm. The coating was cured at 21° C. for 7 days and at 80° C. for 1 day. After the coating cured, it was cut into strips of appropriate size (rectangular strips, 60 mm x 5 mm) for use in a tension film clamp on a TA Q800 DMA machine. The method is described in detail below. The peak of the tangent delta curve was taken as the Tg value.

[0239] Absorption test: Components A and B were mixed and applied onto Mylar® polyester sheets. The coating thickness (dry film) was in the range of 200-400 μm. The coating was cured at 21° C. for 7 days and at 80° C. for 1 day. After the coating cured, it was cut into squares of appropriate size (approximately 2 cm×2 cm).

[0240] Test Method

[0241] Tg was measured by dynamic mechanical analysis (DMA) using the following parameters: 1. Instrument DMA Q800 V21.3 Build 96 2.Module DMA Multi-Frequency-Strain 3. Clamp tension: film 4. Geometric Rectangle (length, width, thickness) 5. Static load 0.0100N 6. Method: (1) Equilibrate at -20.00°C, (2) allowing to isotherm for 3.00 minutes; (3) Ramp to 250.00°C at 4.00°C / min; (4) Equilibrate at 30.00°C. The peak of the tangent delta curve was taken as the Tg value.

[0242] Xylene absorption was tested by immersing samples in xylene for 1 day. The samples were removed and immediately weighed. Xylene absorption is reported in wt% and is measured as the difference in sample weight before and after immersion in xylene.

[0243] 1,2-Dichloroethane absorption was tested by immersing the samples in 1,2-dichloroethane for one day. The samples were removed and immediately weighed. 1,2-Dichloroethane absorption is reported in wt% and is measured as the difference in weight of the sample before and after immersion in 1,2-dichloroethane.

[0244] The test results are also shown in the table below, where CE means comparative example. Comparative examples 1-3 contain different di- and tri-glycidyl ethers. Comparative example 4 is a commercial product, which contains resorcinol diglycidyl ether. Comparative example 5 does not contain low molecular weight epoxy compounds.

[0245] [Table 2]

[0246] [Table 3]

[0247] [Table 4]

[0248] [Table 5]

[0249] 1CE4: A commercial tank coating based on resorcinol diglycidyl ether (RDGE) and an epoxy-based binder (Interline 9001).

[0250] 2 CE5: A commercial tank coating based on a Novolac epoxy-based binder that does not contain low molecular weight diglycidyl ethers or triglycidyl ethers.

[0251] The results show that the coatings containing the binder system of the present invention (Examples 1, 2 and 3) have significantly higher Tg (155, 164 and 138° C.) compared to the CEs containing different di- and tri-glycidyl ethers (CE1-CE3, Tgs between 91-124° C.). The Tg of the coatings containing the binder system of the present invention is also significantly higher than the Tg of the commercial reference tank coating (CE5).

[0252] The results also show that the combination of an epoxy binder with TMETGE results in a coating with a high Tg and therefore high density. CE5, which does not contain the low molecular weight diglycidyl ether compound, has a significantly lower Tg of 117°C.

[0253] The results of the absorption test confirm those obtained during the DMA test. The inventive examples absorb significantly less xylene and EDC compared to the coatings in the CEs (CE1-CE3) containing different di- and tri-glycidyl ethers, and in CE5, which does not contain the lower molecular weight di- or triglycidyl ethers. This is especially evident in the EDC test.

[0254] The coating in CE4 is based on a combination of resorcinol diglycidyl ether (RDGE) and an epoxy-based binder. This coating absorbs slightly less xylene and EDC than the inventive examples, but the inventive coating will have a significantly improved health and safety profile since it does not contain RDGE, which has been classified as suspected of causing cancer and genetic abnormalities. This makes the inventive coating a relatively safe way to obtain coatings with higher crosslink density and lower chemical absorption than those known in the art.

Claims

1. A binder system comprising: (i) an epoxy binder; (ii) trimethylolethane triglycidyl ether; (iii) a curing agent; and (iv) a homopolymerization accelerator, wherein the weight percentage of trimethylolethane triglycidyl ether based on the total dry weight of the binder system is higher than the weight percentage of the epoxy binder based on the total dry weight of the binder system, the binder system.

2. The binder system according to claim 1, wherein the trimethylolethane triglycidyl ether has an epoxy equivalent of 118 to 128.

3. The binder system according to claim 2, wherein the trimethylolethane triglycidyl ether has a CAS number of 68460-21-9 and / or has a solid content of 100% by weight.

4. The binder system according to any one of claims 1 to 3, wherein the trimethylolethane triglycidyl ether is present in an amount of 50 to 90% by weight based on the total dry weight of (i) the epoxy binder and (ii) the trimethylolethane triglycidyl ether.

5. The binder system according to any one of claims 1 to 3, wherein the weight ratio of trimethylolethane triglycidyl ether to the epoxy binder system is 1:1 to 100:

1.

6. The binder system according to any one of claims 1 to 3, wherein the curing agent contains at least one amine group, preferably an alicyclic amine or a polyamine.

7. The binder system according to any one of claims 1 to 3, wherein the homopolymerization accelerator is imidazole or a phosphonium ionic liquid.

8. A coating composition comprising the binder system according to any one of claims 1 to 3.

9. A method for producing the binder system according to any one of claims 1 to 3, or a coating composition comprising the binder system according to any one of claims 1 to 3, the method comprising mixing: (i) an epoxy binder; (ii) trimethylolethane triglycidyl ether; (iii) a curing agent; and (iv) a homopolymerization accelerator.

10. A kit for generating a binder system according to any one of claims 1 to 3, or a coating composition comprising the binder system according to any one of claims 1 to 3, the kit comprising: (a) a first container containing an epoxy binder and trimethylolethane triglycidyl ether; and (b) a second container containing a curing agent and a homopolymerization accelerator.

11. A container comprising the binder system according to any one of claims 1 to 3, or a coating composition comprising the binder system according to any one of claims 1 to 3.

12. A method of providing a coating on a surface, preferably a metal surface, the method comprising: (i) applying the composition according to claim 8; and (ii) curing the composition to form a coating on the surface.

13. A coating obtained by the method according to claim 12.

14. A coating comprising the binder system according to any one of claims 1 to 3, or a coating composition comprising the binder system according to any one of claims 1 to 3.

15. Use of the composition according to claim 8 for forming a coating on at least one surface of a substrate, or an article, preferably a tank.

16. Use of the binder system according to any one of claims 1 to 3 for forming a coating composition.

17. Use of trimethylolethane triglycidyl ether for forming the binder system according to any one of claims 1 to 3.