Composition

Abstract

The present invention relates to a coating composition, preferably a primer, comprising: (i) an epoxy-based binder; (ii) an epoxy silane, wherein the epoxy silane comprises an ethyoxyl group and a methoxyl group; (iii) zinc, preferably zinc dust; (iv) a curing agent; and (v) preferably an aminoalkylalkoxysilane wherein the solids content of the composition is at least 75% by volume and the VOC content of the composition is 10% by weight or less.

Description

Technical Field

[0001] The present invention relates to a coating composition, preferably a primer composition, and a method and kit for preparing the composition. The present invention also relates to a container for containing the composition, a method for providing a coating on a surface (including applying the composition), and a coating on a surface comprising or derived from the composition. Furthermore, the present invention relates to the use of a composition as described herein for forming a coating on at least one surface of an article. Background Art

[0002] There is a growing demand for paints with low or no volatile organic compounds (VOCs), driven by government regulations requiring manufacturers to find green solutions to reduce the amount of VOCs in their products, and also driven by consumer desire to adopt environmentally friendly products.

[0003] To date, there are no commercially available low-VOC epoxy zinc-rich primers on the market. Zinc-rich primers are those that form a coating with a zinc dust (or zinc dust) pigment content equal to or greater than 80% by mass in the dried coating. Primers containing zinc dust have anti-corrosion properties. Such coatings are widely used in, for example, the marine and oil and gas industries, where they are frequently exposed to atmospheric corrosion environments, for example up to corrosion class C5 according to ISO 12944-2:2017. Anti-corrosion coatings are commonly used, among others, on bridges, fences, oil refinery equipment, pipelines, power plants, storage tanks, containers, windmills, turbines, and steel structures forming part of buildings (e.g., airports, museums, stadiums).

[0004] In zinc dust-containing coatings, the zinc dust acts as a conductive pigment to provide anodic protection. That is, the zinc dust acts as a sacrificial anode and prevents anodic oxidation of the metal substrate it protects. The anodic protection provided by the zinc dust in zinc-containing coatings relies on the flow of current in the coating and, therefore, on the presence of sufficient zinc to support this current flow. Traditionally, zinc dust in anti-corrosion coatings is densely packed and present at a high weight percentage to ensure this.

[0005] The presence of relatively high amounts of zinc dust (e.g., typically 50-80% by weight) in a coating composition can be problematic. The presence of relatively high amounts of zinc dust in a coating composition increases its density and can cause sedimentation during storage. Zinc from the coating can also leach into the environment, which can be detrimental.

[0006] Epoxy zinc-rich primers are required to meet many requirements, including:

[0007] At least 80% by weight of zinc dust in the dry film (i.e. paint) (in accordance with ISO 12944-5:2019)

[0008] Storage stability

[0009] Suitable for traditional airless spray equipment

[0010] Dry and cure to dry state within 6 hours at 23°C

[0011] Low shrinkage after curing

[0012] Excellent corrosion resistance, for example, it should pass a condensation exposure test lasting at least one month and a salt spray test lasting at least two months (in compliance with ISO 12944-6:2018 C5 high requirements)

[0013] Compatible with various epoxy primers as intermediate coatings

[0014] Furthermore, in order to meet various environmental regulations that have been implemented and / or may be implemented in the next few years, the solid volume of the composition should be at least 80% and the VOC weight ratio should be less than 10%.

[0015] However, it has proven difficult to prepare epoxy zinc-rich primers with high solid volumes while maintaining their applicability. The epoxy and amine curing agents used to prepare these primers are viscous, making it difficult to develop compositions with low viscosity and correspondingly high applicability. As a result, the solid volume of conventional epoxy zinc-rich primers is typically around 60%. As the solid volume increases further and the VOC decreases, the viscosity of the composition increases and it becomes difficult to apply. Furthermore, it is impossible to use highly viscous compositions to prepare relatively thin coatings, as required for certain applications. This is because viscous compositions have poor flow and leveling properties and therefore require a relatively high wet film thickness to evenly cover the substrate. Accordingly, this results in relatively thick dry film thicknesses, typically up to 90 μm or more. (In comparison, the typical dry film thickness of epoxy zinc-rich primers is only about 60-70 μm).

[0016] Another problem with using high zinc-rich compositions (above 80%) is that they typically have poor storage stability due to the extremely high zinc dust density (7.1 g / cm 3 ) and therefore the zinc dust will settle. Typically, thixotropic agents are added in an effort to achieve stability in these situations.

[0017] In an effort to overcome the shortcomings of commercially available epoxy zinc-rich primers, it is known to add one or more reactive epoxy diluents to the composition. This has the effect of reducing the viscosity of the composition, thereby improving its applicability and its ability to form a relatively thin coating. However, adding a reactive epoxy diluent to the composition also has disadvantages. For example, it tends to negatively impact the corrosion resistance of the coating and its adhesion to the substrate. It is also common for compositions containing reactive epoxy diluents to have unacceptably long drying times and to result in the formation of a soft film. Therefore, adding a reactive epoxy diluent to an epoxy zinc-rich primer composition is not an ideal solution. Summary of the Invention

[0018] Viewed from a first aspect, the present invention provides a coating composition, preferably a primer, comprising:

[0019] (i) Epoxy-based binder;

[0020] (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0021] (iii) zinc, preferably zinc dust;

[0022] (iv) a curing agent; and

[0023] (v) preferably, aminoalkylalkoxysilane,

[0024] wherein the composition has a solids content of at least 75% by volume and a VOC content of 10% by weight or less (based on the total volume and weight of the composition, respectively).

[0025] Viewed from another aspect, the present invention provides a method for preparing a composition as hereinbefore described, comprising mixing:

[0026] (i) Epoxy adhesives;

[0027] (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0028] (iii) zinc, preferably zinc dust;

[0029] (iv) a curing agent; and

[0030] (v) Preferably, aminoalkylalkoxysilane.

[0031] From another aspect, the present invention provides a kit for preparing the composition as described above, comprising:

[0032] (i) a first container containing an epoxy-based adhesive, epoxy silane (wherein the epoxy silane contains ethoxy groups and methoxy groups), and zinc (preferably zinc dust); and

[0033] (ii) A second container containing a curing agent and preferably, an aminoalkylalkoxysilane.

[0034] From another aspect, the present invention provides a container containing the composition as described above.

[0035] Viewed from another aspect, the present invention provides a method of providing a coating on a surface, the method comprising:

[0036] (i) applying the composition as described above; and

[0037] (ii) drying and / or curing the composition to form a coating on the surface.

[0038] Viewed from another aspect the invention provides a coating on a surface wherein said coating comprises or is derived from a composition as hereinbefore described.

[0039] Viewed from another aspect, the present invention provides a use of the composition as described above for forming a coating on at least one surface of an article.

[0040] definition

[0041] As used herein, the term "volatile organic compound" refers to a compound having a boiling point ≤ 250° C. at 101.3 kPa. This is the definition given in EU Directive 2004 / 42 / CE.

[0042] As used herein, the term "coating composition" refers to a composition that, when applied to a surface, forms a film or coating thereon.

[0043] As used herein, the term "primer" refers to a composition that is applied directly to the surface of an article, i.e., without the need for prior application of another coating. Typically, another composition is applied on top of the primer.

[0044] As used herein, the term "binder" refers to a polymer that forms a continuous film on a substrate surface when applied thereto. The other components of the composition are dispersed throughout the binder.

[0045] As used herein, the term "epoxy" refers to polymers or oligomers containing epoxy groups and / or modified epoxy groups. The term epoxy adhesive encompasses adhesives having a traditional epoxy backbone (i.e., the same backbone as the corresponding epoxy resin, such as a bisphenol-based backbone) but in which the epoxy end groups are modified with, for example, acrylic or methacrylic functional groups that can be cured using the same curing agents as epoxy groups. Typically, epoxy adhesives will contain at least some epoxy groups. The terms epoxy and epoxide are used interchangeably.

[0046] As used herein, the term "liquid epoxy resin" refers to an epoxy polymer that is liquid at ambient temperature and pressure (25° C. and 1 atm). The term "liquid" refers to the physical state of the epoxy-based adhesive.

[0047] As used herein, the term "epoxy" refers to a three-atom cyclic ether.

[0048] As used herein, the term "epoxy adhesive system" refers to a combination of one or more epoxy resins with one or more curing agents, accelerators, and optionally reactive diluents.

[0049] As used herein, the term "equivalent epoxy weight" or "EEW" refers to the number of grams of epoxy-functional compound (epoxy adhesive) that is equivalent to 1 mol of epoxy groups. It is determined according to ASTM D1652.

[0050] As used herein, the term "AHEW" refers to "amine hydrogen equivalent weight," which is the mass (in grams) of a curing agent (a compound containing (reactive) active amine hydrogen) equivalent to 1 mol of active amine hydrogen. It can be determined by potentiometric titration (ISO 9702:1996).

[0051] As used herein, "ambient temperature curable" refers to a coating composition that, after application to a substrate, is capable of curing in the presence of ambient air. Typically, the relative humidity of the air will be 10-100%, for example, 15 to 78%. Typically, the temperature of the air will be 5-50°C, preferably 5-40°C, more preferably 10-35°C, for example, 15-30°C.

[0052] As used herein, the term "curing" refers to the process by which the crosslinkable components of the composition are at least partially crosslinked, and preferably crosslinked. Those skilled in the art will understand that the presence and extent of crosslinking is evidenced by certain properties of the coating.

[0053] As used herein, the term "curing agent" refers to a compound that, when mixed with an epoxy resin, produces a cured or hardened coating by generating crosslinks within the polymer. Typically, a curing agent is a compound that supplies reactive hydrogens that are transferred to the epoxide of the adhesive in an epoxy ring-opening reaction. More specifically, in the composition herein, the curing agent copolymerizes with the epoxy resin and forms a polymer network due to the multifunctionality of the curing agent. Sometimes a curing agent is referred to as a hardener.

[0054] As used herein, the terms "cure accelerator" and "accelerator" are used synonymously and refer to compounds that increase the rate of the curing reaction to cause the coating to cure or harden.

[0055] As used herein, the term "epoxysilane" refers to a compound containing at least one epoxy group and at least one silane group.

[0056] As used herein, the term "spherical" when used with respect to particles (e.g., zinc or glass particles) encompasses both substantially spherical and spherical particles. Substantially spherical particles have the same size in each of the x, y, and z dimensions, ± 1.2 μm, more preferably ± 0.6 μm.

[0057] As used herein, the term "mean diameter" refers to the median diameter size (D 50 ).

[0058] As used herein, the term D 50 It refers to the diameter for which 50% of the distribution of particles have a smaller particle size and 50% of the distribution have a larger particle size.

[0059] As used herein, the term D 99 =D is the diameter for which 99% of the distribution has a smaller particle size and 1% has a larger particle size. The other D values ​​follow the same pattern. For example, as used herein, the term D 88 This refers to the diameter for which 88% of the distribution has a smaller particle size and 12% has a larger particle size.

[0060] As used herein, the term "dust" refers to spherical particles having an average diameter in the range of 3 to 20 μm. Thus, dust is a type of particle, specifically relatively small particles.

[0061] As used herein, the term "powder" refers to spherical particles having an average diameter in the range of 21 to 100 μm. Thus, powder is a type of particle that is larger than dust.

[0062] Unless otherwise indicated, as used herein, the term "weight % (wt %)" when used with respect to an individual ingredient of a composition refers to the actual weight of the ingredient, ie, without volatile components.

[0063] As used herein, the term "weight % (wt %)" when used with respect to a coating composition refers to weight relative to the total weight of the composition (ie, including non-volatile and volatile components), unless otherwise indicated.

[0064] As used herein, the term "weight % (wt %)" when used with respect to a dry coating refers to the weight relative to the total weight of the dry coating (ie, excluding volatile components), unless otherwise indicated.

[0065] As used herein, the term "volume % (vol %)" when used with respect to a coating composition refers to the volume relative to the total volume of the composition.

[0066] Unless otherwise indicated, the term "molecular weight" as used herein refers to the weight average molecular weight (Mw), which is determined by gel permeation chromatography.

[0067] As used herein, the term "density" refers to the density as determined by the pycnometer method (ISO 2811-1:2016).

[0068] As used herein, the term "pigment volume concentration (PVC)" refers to the ratio of the volume of pigment and other solid particles to the total volume of non-volatile matter in a composition. DETAILED DESCRIPTION

[0069] The present invention relates to a coating composition, preferably a primer composition, comprising:

[0070] (i) Epoxy adhesives;

[0071] (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0072] (iii) zinc, preferably zinc dust;

[0073] (iv) a curing agent; and

[0074] (v) preferably, aminoalkylalkoxysilane,

[0075] wherein the composition has a solids content of at least 75% by volume and a VOC content of 10% by weight or less (based on the total volume and total weight of the composition, respectively).

[0076] Optionally, the coating composition of the present invention further comprises: (vi) fillers, such as microspheres; (vii) rheology modifiers; (viii) leveling agents; (ix) defoamers; (x) dispersants; (xi) other binders; (xii) solvents; and / or (xiii) additives.

[0077] The coating composition of the present invention is advantageously an epoxy zinc primer composition having a relatively high solids content (i.e., at least 75% by volume) and a VOC content of 10% by weight or less, while retaining the key properties of providing strong corrosion protection and having a sufficiently low viscosity to enable application by conventional techniques (e.g., airless spray guns). The desirable viscosity of the coating composition of the present invention also means that it can be used to prepare relatively thin coatings, for example, coatings having a wet film thickness of approximately 60 microns.

[0078] Furthermore, the compositions of the present invention are storage stable, for example, their viscosity does not change significantly during storage and / or the zinc present therein does not settle. As mentioned above, this is a particular challenge encountered with such compositions. The coating compositions of the present invention also have desirable drying and curing times. Thus, a typical coating composition of the present invention is completely dry within 6 hours at 23°C.

[0079] Epoxy adhesives

[0080] In the coating composition of the present invention, the binder is epoxy-based, and preferably epoxy. The epoxy-based binder may be a modified epoxy-based binder. Optionally, the epoxy-based binder is modified with fatty acid, polypropylene oxide and / or polyethylene oxide.

[0081] The coating composition of the present invention may include one or more epoxy-based adhesives (e.g., epoxy adhesives). A preferred coating composition includes 1, 2 or 3 epoxy-based adhesives (e.g., epoxy adhesives), most preferably one epoxy-based adhesive (e.g., one epoxy adhesive).

[0082] The preferred epoxy-based binder (e.g., epoxy adhesive) in the coating composition of the present invention has an equivalent epoxy weight (EEW) of 100-1000 g / eq, more preferably 120 to 500 g / eq, still more preferably 150-270 g / eq, and still more preferably 160-200 g / eq.

[0083] The epoxy adhesive (e.g., epoxy adhesive) is preferably a liquid epoxy adhesive. The equivalent epoxy weight (EEW) value of the liquid epoxy adhesive is preferably 100 to 1000, and more preferably 120-500 g / eq. More preferred epoxy liquid adhesives have an EEW of less than 500 g / eq. The viscosity of the liquid epoxy adhesive is preferably 1000-7500 mPas, more preferably 1500-6000 mPas, and even more preferably 2000-5000 mPas.

[0084] Preferred epoxy adhesives contain more than one epoxy group per molecule.Such epoxy groups may be located internally or at a terminal position within the epoxy adhesive or on a cyclic structure that is integrated into the epoxy adhesive.

[0085] It should be understood that the epoxy adhesives of the present invention encompass adhesives having a conventional epoxy backbone (i.e., the same backbone as the corresponding epoxy resin, such as a bisphenol-based backbone) but in which the epoxy end groups have been modified with acrylic or methacrylic functional groups that can be cured using the same curing agents as the epoxy groups. In these epoxy adhesives, the end groups are preferably functionalized with acrylic and / or methacrylic functional groups.

[0086] Preferably, the coating composition of the present invention comprises one or more epoxy-based adhesives (eg, epoxy adhesives) selected from aromatic or aliphatic epoxy-based adhesives.

[0087] Representative examples of suitable aliphatic epoxy-based adhesives include epoxy adhesives and modified epoxy adhesives selected from the group consisting of alicyclic epoxies such as hydrogenated bisphenol A, dicyclopentadiene-based adhesives, glycidyl ethers such as polyglycidyl ethers of polyols, epoxy-functional acrylic resins, or any combination thereof.

[0088] Representative examples of suitable aromatic epoxy adhesives include epoxy adhesives and modified epoxy adhesives selected from the group consisting of bisphenol-type epoxy adhesives such as bisphenol A, bisphenol F and bisphenol S, novolac-type epoxy adhesives such as phenol novolac-type adhesives (bisphenol A novolac) and cresol novolac-type adhesives, or any combination thereof.

[0089] Preferably, the one or more epoxy-based adhesives are selected from aromatic epoxy-based adhesives. Preferably, the aromatic epoxy-based adhesive is derived from a combination of a compound comprising at least one epoxy functionality and an aromatic co-reactant comprising at least two hydroxyl groups.

[0090] Particularly preferred epoxy adhesives are bisphenol epoxy adhesives. Examples of such epoxy adhesives include bisphenol A epoxy adhesives, bisphenol F epoxy adhesives, and bisphenol A / F epoxy adhesives. Bisphenol epoxy adhesives may be modified adhesives. Such modifications may include fatty acid modification or polyether modification by reacting polyethylene oxide or polypropylene oxide segments.

[0091] Particularly preferably, the epoxy adhesive is a bisphenol F epoxy adhesive. Even more preferably, the epoxy adhesive is an unmodified liquid bisphenol F epoxy resin. This epoxy adhesive is preferred because it has a particularly low viscosity and results in a coating with excellent adhesion and corrosion protection properties.

[0092] Preferably, the bisphenol-based epoxy adhesive has an epoxy equivalent weight (EEW) of 150-270 g / eq and more preferably 160-200 g / eq.

[0093] Examples of suitable commercially available epoxy-based adhesives for use in the compositions of the present invention are:

[0094] -Bisphenol A epoxy adhesives: DER 331 and DER 332 from Olin Epoxy

[0095] - Bisphenol F epoxy adhesives: Epikote 862 from Hexion, DER354 from Olin Epoxy.

[0096] - A mixture of bisphenol A and bisphenol F epoxy adhesives: DER 352 from Olin Epoxy, Epikote 235 from Hexion.

[0097] The solid content of the epoxy adhesive is preferably greater than 70 wt %, preferably greater than 80 wt %, preferably greater than 90 wt %, and most preferably greater than 99 wt % (based on the total weight of the adhesive). Preferably, the solid content of the epoxy adhesive is 100 wt %, i.e., it does not contain a solvent.

[0098] The total amount of epoxy-based binder present in the coating composition of the present invention is preferably 3-15 wt %, more preferably 5-10 wt % and even more preferably 6-8 wt % (based on the total weight of the composition). If a blend of epoxy-based binders is used, these percentages refer to the total content of epoxy-based binder.

[0099] Epoxy silane

[0100] Epoxysilane, wherein the epoxysilane comprises ethoxy and methoxy groups.

[0101] The coating composition of the present invention comprises one or more epoxy silanes. Preferably, the coating composition comprises a mixture of epoxy silanes (eg, two or three, preferably two epoxy silanes).

[0102] Epoxysilanes are generally unstable in zinc-rich epoxy compositions, and it is assumed that they gradually undergo hydrolysis with water introduced via other ingredients to form silanols. The gelation of these silanols causes an undesirable increase in viscosity. It has now been found that ethoxy-containing epoxysilanes are more stable than methoxy-containing epoxysilanes, so their presence improves storage stability. On the other hand, methoxy-containing epoxysilanes improve drying and curing speed. It has been found that the presence of a mixture of methoxy- and ethoxy-containing epoxysilanes provides a desired balance of drying and curing speed and storage stability. This is especially true when aminoalkylalkoxysilanes are also present.

[0103] In the coating composition of the present invention, the epoxy silane is preferably 3-glycidyloxyalkylalkoxysilane and more preferably 3-glycidyloxypropylalkoxysilane. Still more preferably, the epoxy silane is 3-glycidyloxyalkyltri-, di- or monoalkoxysilane, and still more preferably 3-glycidyloxypropyltri-, di- or monoalkoxysilane.

[0104] In the coating composition of the present invention, the epoxysilane preferably has formula (I):

[0105] (I)

[0106] in

[0107] n is an integer from 1 to 6;

[0108] R is a C1-12 alkyl group;

[0109] Each R a are independently methyl or ethyl; and

[0110] b is an integer from 1 to 3.

[0111] In the preferred epoxysilanes of formula (I), n is 3, ie, propyl.

[0112] In further preferred epoxysilanes of the formula (I), b is 2 or 3, in particular 3.

[0113] The coating composition of the present invention may comprise an epoxysilane of formula (I), wherein at least one R a is a methyl group, and at least one R a It's ethyl.

[0114] More preferably, the coating composition of the present invention comprises a mixture of epoxysilanes of formula (I). Preferably, the mixture comprises wherein R aThe first epoxysilane of formula (I) is a methyl group and wherein R a The second epoxysilane of formula (I) is an ethyl group. In other words, the coating composition comprises a mixture of epoxysilanes containing methoxy groups and ethoxy groups.

[0115] Examples of preferred epoxy silanes present in the coating compositions of the present invention include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropylethyldimethoxysilane, 3-glycidoxypropyldiethylmethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylethyldiethoxysilane, 3-glycidoxypropyldiethylethoxysilane, and combinations thereof.

[0116] A particularly preferred coating composition of the present invention comprises a first epoxy silane selected from the group consisting of 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyldimethylmethoxysilane, 3-glycidoxypropylethyldimethoxysilane, 3-glycidoxypropyldiethylmethoxysilane, and combinations thereof; and a second epoxy silane selected from the group consisting of 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyldimethylethoxysilane, 3-glycidoxypropylethyldiethoxysilane, 3-glycidoxypropyldiethylethoxysilane, and combinations thereof. An especially preferred coating composition of the present invention comprises 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane.

[0117] In a preferred coating composition of the present invention, the one or more epoxy silanes present comprise methoxy and ethoxy groups in a mass ratio of 3:1 to 1:3, preferably 2:1 to 1:2, and more preferably about 1:1.

[0118] Examples of such epoxysilanes are commercially available from, for example, Evonik Industries AG, Momentive, and Wacker. Specific examples include 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO, Silquest A-187) and 3-glycidoxypropyltriethoxysilane (Dynasylan GLYEO).

[0119] The total amount of epoxysilane in the coating composition of the present invention is preferably 1-10 wt %, more preferably 1.5-7.5 wt % and even more preferably 2-5 wt %, based on the total weight of the composition. If a blend of epoxysilanes is used, these percentages refer to the total content of epoxysilane.

[0120] zinc

[0121] The coating composition of the present invention comprises zinc, and preferably comprises zinc dust. Preferred zinc dust present in the coating composition comprises at least 90 wt % zinc, such as at least 95 wt %, more preferably at least 97 wt % and even more preferably at least 98 wt % zinc. The amount of zinc may be upper limited to 100 wt %.

[0122] Preferably, the zinc dust present in the coating composition of the present invention is substantially spherical. In preferred coating compositions, the zinc dust has a particle size of 1-20 μm, more preferably 2-10 μm and even more preferably 3-7 μm, as measured by a Fisher sub sieve sizer (ASTM B330-07). Further preferred zinc dust has a particle size D as measured by laser diffraction. 50 is 1-20 μm, more preferably 2-10 μm and still more preferably 3-8 μm, and D 90 5 to 30 μm, more preferably 6 to 20 μm and still more preferably 8 to 15 μm. The particle size of zinc dust referred to herein is their size when the particles are added to the composition and before any extrusion or grinding process.

[0123] The preferred zinc dust present in the coating composition of the present invention has a bulk density of 1 to 3.5 g / cm 3 and more preferably 2 to 3.0 g / cm 3 .

[0124] The preferred zinc dust present in the coating composition of the present invention has a specific gravity of 6 to 9 g / cm 3 and more preferably 7 to 8 g / cm 3 , which is measured at 20°C according to ISO 787-10.

[0125] Zinc dust used in the coating composition of the present invention is commercially available, for example, from Everzinc, PurityZinc Metals, Umicore, and the like.

[0126] Optionally, the coating composition of the present invention may contain zinc in other forms, such as zinc flakes and / or zinc powder.

[0127] Zinc flakes have a layered or plate-like structure. Zinc flakes are typically produced by ball milling zinc dust in a non-reactive fluid (such as a hydrocarbon). Milling causes each dust particle to flatten into a flake form.

[0128] Zinc flakes differ from other forms of zinc, including zinc dust and zinc powder, in their aspect ratio and density. Preferred zinc flakes have an aspect ratio of 5:1 to 60:1, more preferably 10:1 to 50:1 and even more preferably 20:1 to 40:1.

[0129] When present in the coating composition, the zinc flakes are generally planar. Preferred zinc flakes have a thickness of 0.1 to 5 μm, more preferably 0.2-2 μm and even more preferably 0.3-1 μm. Preferred zinc flakes have a thickness of less than 3 μm, for example 0.1 to 2.8 μm.

[0130] Zinc flakes suitable for use in the compositions of the present invention are commercially available from Eckart under the trade names STANDART® Zinc Flake and ProFLAKE.

[0131] A preferred coating composition of the present invention does not contain zinc flakes. A further preferred coating composition of the present invention does not contain zinc powder. An even further preferred coating composition of the present invention does not contain zinc flakes or zinc powder. In other words, it is preferred if all zinc present in the coating composition is in the form of zinc dust.

[0132] The total amount of zinc present in the coating composition of the present invention is preferably 65-90 wt%, more preferably 70-85 wt%, and even more preferably 75-80 wt%, based on the total weight of the composition. The total amount of zinc dust present in the coating composition of the present invention is preferably 65-90 wt%, more preferably 70-85 wt%, and even more preferably 75-80 wt%, based on the total weight of the composition.

[0133] curing agent

[0134] The coating composition of the present invention comprises a curing agent. Preferably, the viscosity of the curing agent is less than 1500 mPas, more preferably less than 1000 mPas and even more preferably less than 800 mPas. Preferably, the viscosity of the curing agent is 50-1500 mPas, more preferably 75-750 mPas and even more preferably 85-700 mPas. The low viscosity of the curing agent helps to ensure that the overall viscosity of the coating composition is not too high.

[0135] Preferably, the curing agent is selected from an amine curing agent, a polyamine curing agent and / or an amino-functional polymer curing agent. Preferably, the curing agent is a polyamine curing agent, ie a curing agent comprising at least two amine groups.

[0136] To achieve a crosslinked network, the curing agent must contain at least three "reactive" hydrogen atoms. The term "reactive" with respect to hydrogen atoms refers to hydrogen atoms that are transferred from the nucleophile to the oxygen atom of the epoxide during the ring-opening reaction. Therefore, the active amine groups in the curing agent cannot be tertiary amines. The curing agent preferably contains at least two reactive functional groups for curing, and preferably at least two amine groups. The AHEW of the curing agent present in the coating composition of the present invention is preferably 70-150 g / eq, more preferably 80-130 g / eq, and even more preferably 90-110 g / eq.

[0137] In a preferred coating composition of the present invention, the curing agent comprises at least one benzylamine motif:

[0138]

[0139] Optionally, the benzylamine in the curing agent can be substituted on the ring, methylene linker or N atom, but one active hydrogen must be retained. Suitable substituents include C1-15 alkyl, OH, O-C1-4-alkyl, halogen, cyano, amine and alkylamine groups (C1-4-N).

[0140] The curing agent present in the coating composition of the present invention may comprise two or more repeating units, i.e., the curing agent may be a polymer or an oligomer. Preferably, the curing agent is a polyamine polymer comprising a benzylamine structure at at least one end of the polyamine polymer chain. The polyamine polymer may comprise a benzylamine structure at both ends of the polymer chain. Each repeating unit may also comprise a benzylamine group. The benzylamine group may be substituted or unsubstituted. Suitable substituents are those described above.

[0141] A preferred curing agent present in the coating composition of the present invention comprises at least two or more benzylamine structures. More preferably, the curing agent comprises a benzylated polyalkylene polyamine structure as described in WO2017147138A. Preferably, the benzylated polyalkylene polyamine has formula (II):

[0142] (II)

[0143] in

[0144] R 1 is a substituted or unsubstituted benzyl group;

[0145] Each R 2 Independently selected from R 1 or a hydrogen atom, or a group selected from C1-C16 linear, cyclic or branched alkyl, alkenyl and alkaryl groups;

[0146] X, Y and Z are independently selected from C2-C10 alkylene and cycloalkylene, preferably ethylene, propylene, butylene, hexylene, cyclohexyldimethylene and cyclohexylene;

[0147] y is an integer from 1 to 7; and

[0148] z is an integer from 0 to 4.

[0149] Suitable substituents for the benzyl group include C1-15 alkyl, OH, O-C1-4-alkyl, halogen, cyano, amine and alkylamine groups (C1-4-N).

[0150] Examples of suitable benzylated polyalkylene polyamine structures are benzylated polyethylene polyamines, benzylated polypropylene polyamines, benzylated polyethylene-polypropylene polyamines, and combinations thereof.

[0151] Non-limiting examples of polyethylene polyamines include ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA) and other higher polyethylene polyamines. Suitable polypropylene polyamines include propylenediamine (PDA), dipropylenetriamine (DPTA), tripropylenetetramine and other higher polypropylene polyamines. Other polyalkylene polyamines include N-3-aminopropylethylenediamine, N,N'-bis(3-aminopropyl)ethylenediamine and N,N,N'-tris(3-aminopropyl)ethylenediamine, N-3-aminopropyldiethylenetriamine; N-3-aminopropyl-[N'-3-[N-3aminopropyl]aminopropyl]diethylenetriamine; N,N'-bis(3-aminopropyl)-diethylenetriamine; N,N-bis(3-aminopropyl)diethylenetriamine; N,N,N'-tris(3-aminopropyl)ethylenediamine; diethylenetriamine; N,N',N"-tris(3-aminopropyl)diethylenetriamine; N,N',N"-tetra(3-aminopropyl)diethylenetriamine; N,N-bis(3-aminopropyl)-[N'-3-[N-3-aminopropyl]aminopropyl]-[N'-3-aminopropyl]diethylenetriamine; and N-3-aminopropyl-[N'-3-[N-3-aminopropyl]aminopropyl]-[N'-3-aminopropyl]diethylenetriamine.

[0152] Benzylated polyalkylene polyamine structures are typically prepared by reductive amination of benzaldehyde (including substituted and unsubstituted benzaldehydes) with polyalkylene polyamines. Examples of substituted benzaldehydes are benzaldehydes in which the aromatic ring is substituted with one or more halogen atoms, C1-C4 alkyl groups, methoxy groups, ethoxy groups, amino groups, hydroxyl groups, or cyano groups. Preferred benzaldehydes are benzaldehyde and vanillin.

[0153] The AHEW of the polyamine curing agent present in the coating composition of the present invention is preferably 70 - 150 g / eq, more preferably 80 - 130 g / eq and still more preferably 90 - 110 g / eq.

[0154] The total amount of curing agent present in the coating composition of the present invention is preferably 0.5-10 wt %, preferably 1-7.5 wt % and more preferably 2-4 wt %, based on the total weight of the composition. If a blend of curing agents is used, these percentages refer to the total content of curing agent.

[0155] curing accelerator

[0156] The coating composition of the present invention optionally comprises a curing accelerator. Typically, a curing accelerator increases the cure rate of the composition. For amine-cured epoxy compositions, phenolic compounds, salts of strong acids, tertiary amine compounds, and acrylates are preferably used as curing accelerators.

[0157] Phenolic compounds that can be suitable curing accelerators include compounds such as phenol, bisphenol, alkylphenols (including cardanol), and benzoic acid derivatives such as salicylic acid. Salts of strong acids that can be suitable as curing accelerators include trifluoromethanesulfonates of metals in Group 2 of the periodic table, such as Mg and Ca. Tertiary amine compounds that are suitable as curing accelerators include 3-aminopropyldimethylamine, benzyldimethylamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, dimethylethanolamine, diethylethanolamine, triethanolamine, and 2,4,6-tris(dimethylaminomethyl)phenol (Ancamine K54 from Evonik).

[0158] The total amount of curing accelerator in the coating composition of the present invention is preferably 0.05-1 wt %, preferably 0.1-0.5 wt % and more preferably 0.1-0.3 wt %, based on the total weight of the composition. If a blend of curing accelerators is used, these percentages refer to the total content of curing accelerator.

[0159] Aminoalkylalkoxysilane

[0160] The coating composition of the present invention preferably comprises an aminoalkylalkoxysilane, preferably an aminopropylalkoxysilane. The presence of an aminoalkylalkoxysilane typically improves the drying properties of the composition (especially at low temperatures) as well as the adhesion to the substrate and the anti-corrosion properties.

[0161] Preferably, the aminoalkylalkoxysilane present in the coating composition of the present invention has a low Mw, such as less than 400 g / mol.

[0162] Preferably, the aminoalkylalkoxysilane present in the coating composition of the present invention has formula (IIIa) or (IIIb):

[0163] AR 3 (4-k) SiR 4 k (IIIa)

[0164] AR 3 (3-p) SiR 5 R 4 p (IIIb)

[0165] in

[0166] A is with R 3 A bound amine group, and preferably A is NH2;

[0167] R 3 is an alkylene radical having 1 to 12 C atoms, optionally containing an ether or amino linker;

[0168] Each R 4 independently represents a C1-6 alkoxy group;

[0169] R 5 is a hydrocarbon radical having 1 to 12 C atoms;

[0170] k is an integer from 1 to 3; and

[0171] p is an integer of 1 to 2, and preferably 2.

[0172] In the aminoalkylalkoxysilanes of formula (IIIa) and (IIIb), the A group may be connected to the chain R 3 The amino group is preferably NH2.

[0173] In the aminoalkylalkoxysilanes of formula (IIIa) and (IIIb), R 4 Preferably it is methoxy or ethoxy and more preferably methoxy. It is also particularly preferred if two or three alkoxy groups are present. Therefore, k is preferably 2 or 3, especially 3. The subscript p is preferably 2.

[0174] In the aminoalkylalkoxysilanes of formula (IIIa) and (IIIb), R 5 C is preferred 1-4 Alkyl groups, such as methyl.

[0175] In the aminoalkylalkoxysilanes of formula (IIIa) and (IIIb), R 3It is an alkylene radical with up to 12 carbon atoms. An alkylene radical means a group comprising only C and H atoms. It can comprise an alkylene chain or a combination of an alkylene chain and a ring (such as a phenylene ring or a cyclohexylene ring). The term "optionally containing an ether or amino linker" means that the carbon chain can be interrupted by the -O- or -NH- groups in the chain. It is preferred if the group A is not combined with a carbon atom that is combined with such a linker -O- or -NH-.

[0176] Therefore, R 3 It can represent -(C6H4)-NH-(CH2)3- or (C6H4)-(CH2)3, etc.

[0177] R 3 Preference is given to unsubstituted (obviously with the exception of A), unbranched alkylene chains having 2 to 8 C atoms (optionally containing ether or amino linkers).

[0178] Aminoalkylalkoxysilanes of formula (IIIa) are generally preferred. In such compounds, preferably k is an integer from 2 to 3, R 3 is an unsubstituted, unbranched alkylene chain having 2 to 8 C atoms (optionally containing an ether or amino linker), A is 3 The amino group is bound to the R 4 represents an alkoxy group, preferably a methoxy group or an ethoxy group.

[0179] Examples of suitable aminoalkylalkoxysilanes are commercially available, for example, from Evonik Industries AG, Momentive and Wacker. Specific examples include 3-aminopropyltrimethoxysilane (Dynasylan AMMO; Silquest A-1110), 3-aminopropyltriethoxysilane (Dynasylan AMEO), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (Dynasylan DAMO, Silquest A-1120), N-(2-aminoethyl)-3-aminopropyltriethoxysilane, triamino-functional 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (Silquest A-1130), bis[3-(trimethoxysilyl)propyl]amine (Silquest A-1170), N-ethyl-3-trimethoxysilyl-2-methylpropylamine (Silquest A-Link 15), N-phenyl-3-aminopropyltrimethoxysilane (Silquest Y-9669), 4-amino-3,3-dimethylbutyltrimethoxysilane (Silquest Y-11637), (N-cyclohexylaminomethyl)triethoxysilane (Geniosil XL 926), (N-phenylaminomethyl)trimethoxysilane (Geniosil XL 973) and Deolink Amino TE (DOG Deutsche Oelfabrik), and mixtures thereof. Other suitable aminoalkylalkoxysilanes are available from Gelest, such as 4-aminobutyltriethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 4-amino-3,3-dimethylbutylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-aminopropyldimethylethoxysilane, and combinations thereof.

[0180] In the coating composition of the present invention, 3-aminopropyltrimethoxysilane is preferred.

[0181] The total amount of aminoalkylalkoxysilane present in the coating composition is preferably 0.05-5 wt %, preferably 0.1-2 wt % and more preferably 0.1-1.5 wt %, based on the total weight of the composition. If a blend of aminoalkylalkoxysilanes is used, these percentages refer to the total amount of aminoalkylalkoxysilane.

[0182] Reactive diluent

[0183] The coating composition of the present invention optionally contains a reactive diluent. Preferably, the coating composition does not contain a reactive diluent. This ensures strong anti-corrosion properties.

[0184] When present, the reactive diluent preferably has a viscosity of <100 mPas, preferably <50 mPas, and more preferably <30 mPas at 23°C and 50% RH, as measured by the cone and plate method according to ISO 2884-1:2006. This helps to reduce the overall viscosity of the coating composition. Preferred reactive diluents have an epoxy equivalent weight (EEW) of 100 to 500 g / eq, preferably 100 to 300 g / eq, and more preferably 120 to 170 g / eq.

[0185] When present, the reactive diluent is preferably formed from a modified epoxy compound.Preferably, the reactive diluent is multifunctional rather than monofunctional.

[0186] Examples of suitable reactive diluents that may be present in the coating composition of the present invention include phenyl glycidyl ether, alkyl glycidyl ethers (number of carbon atoms in the alkyl group: 1 to 16), glycidyl esters of tertiary carboxylic acids (R 4 R 5 R 6 C-COO-Gly, where R 4 R 5 R 6 is an alkyl group such as a C8 to C10 alkyl group, and Gly is a glycidyl group), olefin epoxides (CH3-(CH2)n-Gly, wherein n=11 to 13, Gly: glycidyl group), 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 neodecanoic acid glycidyl ester. Another preferred embodiment is Cardolite NC-513, which is derived from the reaction of epichlorohydrin with oil obtained from the shell of cashew nuts. p-TBPGE (p-tert-butylphenyl glycidyl ether) may also be used.

[0187] Among the above-mentioned reactive diluents, aliphatic reactive diluents are preferred. Aliphatic reactive diluents are preferably formed by reacting a compound containing at least one aliphatic epoxide functionality with an aliphatic alcohol or polyol (such as 1,6-hexanediol diglycidyl ether or 1,4-butanediol diglycidyl ether). Aliphatic glycidyl ethers with a chain length of 4 to 14 are particularly preferred. Aliphatic reactive diluents are generally preferred because they are believed to contribute to the flexibility of the coating.

[0188] When present, reactive diluents may be used alone or in combination, such as in combinations of two or more diluents.

[0189] The total amount of reactive diluents in the coating composition is preferably 0-5 wt%, more preferably 0.1-4 wt% and even more preferably 0.5-3 wt%.If a blend of reactive diluents is used, these percentages refer to the total content of reactive diluents.

[0190] filler

[0191] The coating composition of the present invention preferably comprises a filler, and more preferably comprises microspheres. The presence of microspheres is beneficial to increase the solid volume of the composition and reduce VOC.

[0192] The microspheres present in the coating compositions of the present invention are generally spherical, and more preferably spherical. This is advantageous because it allows the particles to be packed more closely together in the coating compositions of the present invention. Alternatively, the D 50 The diameter is 10 to 100 μm, more preferably 20 to 80 μm and still more preferably 30 to 70 μm.

[0193] The D of the microspheres was determined as per ISO 13320:2009 using a Malvern Mastersizer 2000. 98 The diameter is preferably 55 to 190 μm, more preferably 75 to 170 μm and still more preferably 95 to 150 μm.

[0194] The microspheres present in the coating composition can be organic or inorganic. Preferably, the microspheres comprise glass, ceramic or plastic, and more preferably consist of glass, ceramic or plastic. More preferably, the microspheres in the coating composition of the present invention comprise ceramic material or glass, and even more preferably consist of ceramic material or glass. Optionally, the microspheres present in the coating composition of the present invention can be surface treated. Optionally, the microspheres can be coated or uncoated.

[0195] The microspheres may be hollow or solid, but are preferably hollow.

[0196] Examples of suitable inorganic microspheres are glass beads or ceramic beads.

[0197] Examples of suitable organic microspheres include beads of polymeric materials such as poly(methyl methacrylate), poly(methyl methacrylate-co-ethylene glycol dimethacrylate), poly(styrene-co-ethylene glycol dimethacrylate), poly(styrene-co-divinyl), polystyrene, poly(vinyl chloride), poly(vinylidene fluoride), and poly(vinylidene chloride).

[0198] Preferably, the coating composition of the present invention comprises solid or hollow inorganic microspheres. Suitable solid or hollow inorganic microspheres are commercially available. Examples include Glass Bubbles S28HS, Micro Bubbles H38HS, Fillite Cenosphere, Poraver (expansion glass), Eccospheres, Q-Cel, Sphericel, Thermospheres, Omega spheres (available from, for example, 3M, SMC Minerals, Omya, Poraver, Trelleborg, Potters, Omega) and hollow glass spheres from Hollowlite.

[0199] Preferably, the coating composition comprises hollow inorganic microspheres, such as cenospheres. This means that the microspheres have a void or cavity at their center. Preferred inorganic hollow microspheres for use in the present invention are substantially hollow. Therefore, preferably, the volume of the void or cavity is at least 70% by volume and more preferably at least 80% by volume of the total volume of the particles. Such voids or empty spaces are preferably filled with gas.

[0200] Preferably, the microspheres have as low a density as possible, for example the density of the microspheres may be 0.1-1 g / cm3, more preferably 0.2-0.9 g / cm3, for example as specified in the technical specifications provided by the supplier. This may reflect the fact that the particles are hollow rather than solid.

[0201] Preferably, the microspheres present in the coating composition of the present invention have an isostatic compressive strength of at least 1500 psi, for example as specified by the supplier in a technical data sheet.

[0202] One preferred coating composition of the present invention comprises 2.0 to 10.0 wt %, more preferably 3.0 to 8.0 wt %, and still more preferably 3.0 to 6.0 wt % microspheres, based on the total weight of the composition.

[0203] Rheology modifiers

[0204] The coating composition of the present invention optionally comprises a rheology modifier. Sometimes, rheology modifiers are also referred to as thixotropic agents. The presence of a rheology modifier can be beneficial in improving the storage stability and / or application characteristics of the composition. For example, a rheology modifier can be used to prevent sedimentation and floating, as well as to adjust leveling and improve anti-sagging properties. Any conventional rheology modifier can be used. For example, an organic rheology modifier and / or an inorganic rheology modifier can be used. A single rheology modifier or a combination thereof can be used. Preferably, a combination of two or three (e.g., two) rheology modifiers is used. A preferred coating composition of the present invention comprises an organic rheology modifier and an inorganic rheology modifier.

[0205] Representative examples of suitable organic rheology modifiers for use in the compositions of the present invention include amide waxes, castor oil derivatives, and rheology modifiers based on acrylic acid, urea, modified urea, polyurethane, amide, or polyamide backbones. The active ingredient of the rheology modifier can be modified with functional groups (such as, for example, polyether and alcohol groups) or surface treated with, for example, silanes. Amide waxes are preferred organic rheology modifiers.

[0206] Representative examples of suitable inorganic rheology modifiers for use in the compositions of the present invention include finely divided silica, bentonite, surface-treated silica (e.g., silane-treated silica), surface-treated bentonite (e.g., organically modified bentonite), surface-treated calcium carbonate, and mixtures thereof. Bentonite is a preferred inorganic rheology modifier.

[0207] Suitable rheology modifiers are commercially available, for example, Bentone SD2 from Elementis, Crayvallac Ultra and Crayvallac LV from Arkema. Preferably, the rheology modifier comprises a micronized amide wax based on a castor oil derivative and bentonite. Even more preferably, the rheology modifier comprises a micronized amide wax based on a castor oil derivative and bentonite in a 1:1 mass ratio.

[0208] The total amount of rheology modifier present in the coating composition of the present invention is preferably 0-5 wt %, more preferably 0.2-3 wt %, and even more preferably 0.3-2 wt %, based on the total weight of the composition. If a blend of rheology modifiers is used, these percentages refer to the total content of rheology modifier.

[0209] Leveling agent

[0210] The coating composition of the present invention optionally comprises a leveling agent. Leveling agents are sometimes also referred to as flow additives.

[0211] Any conventional leveling agent may be used. Acrylic leveling agents are generally preferred.

[0212] Representative examples of suitable leveling agents include BYK-350, BYK-355, BYK-356, BYK-358 N, BYK-359, BYK-361 N, and BYK-388, all available from BYK.

[0213] The amount of leveling agent present in the coating composition of the present invention is preferably 0-5 wt%, more preferably 0.1-2.5 wt% and still more preferably 0.2-1.0 wt%, based on the total weight of the composition.

[0214] defoaming agent

[0215] The coating composition of the present invention optionally comprises a defoamer. Defoamers are sometimes referred to in the art as air release additives.

[0216] Any conventional defoamer may be present in the coating composition of the present invention. Common defoamers can be divided into mineral oil defoamers, silicone defoamers and polymer defoamers. Commercially available defoamers generally contain mixtures of these types, usually in combination with solvents and solid particles.

[0217] Non-restrictive examples of commercial products that can be used in the composition of the present invention include: BYK's Byk-011、Byk-012、Byk-014、Byk-015、Byk-016、byk-0 17、Byk-018、Byk-019、Byk-021、Byk-022、Byk-023、Byk-024、Byk-025、Byk-028、Byk-035、Byk-03 7、Byk-038、Byk-039、Byk-044、Byk-051N、Byk-052N、Byk-053N、Byk-054、Byk-055、Byk-057、Byk-070、Byk-072、Byk-077、Byk-081、Byk-085、Byk-088、Byk-092、Byk-093、Byk-094、Byk-141、Byk-1 610、Byk-1611、Byk-1615、Byk-1616、Byk-1617、Byk-1630、Byk-1640、Byk-1650、Byk-1707、Byk-1709、Byk-1710、Byk-1711、Byk-1719、Byk-1723、Byk-1724、Byk-1730、Byk-1740、Byk-1751、Byk-1 752, Byk-1758, Byk-1759, Byk-1760, Byk-1770, Byk-1780, Byk-1781, Byk-1785, Byk-1786, Byk-1788, Byk-1789, Byk-1790, Byk-1791, Byk-1794, Byk-1795, Byk-1796, Byk-1797, Byk-1799, Byk-A 515, Byk-A 525, Byk-A 530, Byk-A 535, Byk-A 550, Byk-A 555 and Byk-A 560;Tego Airex 901 W, Tego Airex 901 WN, Tego Airex 902 W, Tego Airex 902 WN, Tego Airex 904 W, Tego Airex 904 WN, Airase 4500, Airase 4655, Airase 5355, Airase 5655, Airase 8070, Surfonyl 104. Surfonyl 107L, Surfonyl 420, Tego Foamex 3062, Tego Foamex 8050, Tego Foamex 843, Tego Foamex 844, Tego Foamex 845 Tego Foamex 883, Tego Foamex 1488, Tego Foamex 810, Tego Foamex 811. Tego Foamex 812. Tego Foamex815, Tego Foamex822, Tego Foamex 823 and Tego Foamex 825. ;

[0218] The defoamer is present in the coating composition of the present invention in an amount of 0 to 1.0 wt % and more preferably 0.1 to 0.2 wt % based on the total weight of the composition.

[0219] Dispersants and / or wetting agents

[0220] The coating compositions of the present invention optionally include a dispersant. Dispersants are generally referred to as wetting agents. Dispersants may be present in the coating composition to facilitate the dispersion and wetting of pigment and filler particles, thereby making it easier to break up agglomerates during production, prevent reflocculation and sedimentation in the wet composition, and form Bénard cells in the cured coating, reduce the viscosity of the composition, and improve its color intensity and color stability.

[0221] The dispersant may be nonionic, cationic, anionic, or comprise a mixture of the foregoing.

[0222] Dispersants can be composed of polymers, or non-polymeric organic molecules, or mixtures thereof.

[0223] Non-limiting examples of suitable types of dispersants include fatty acids, lecithin, polysorbates, polyacrylamides, polyether carboxylates, polycarboxylates, polyalkylene glycols, polyethers, polyesters, phosphate polyesters, and polyacrylates.

[0224] Non-limiting examples of commercially available dispersants that can be employed in the compositions of the present invention include: Disperbyk-102, Disperbyk-106, Disperbyk-109, Disperbyk-110, Disperbyk-142, Disperbyk-161, Disperbyk-180, Disperbyk-182, Disperbyk-2000, Disperbyk-2014, Disperbyk-2055, Disperbyk-2059, Disperbyk-2070, Disperbyk-2152 from BYK; Colorol F from Evonik; Adlec soy lecithin and Yelkin soy lecithin from ADM.

[0225] The amount of dispersant present in the coating composition of the present invention is preferably 0 to 1.5 wt % and more preferably 0.1 to 1 wt % based on the total weight of the composition.

[0226] Adhesives

[0227] The coating composition of the present invention optionally comprises a binder (in addition to the epoxy-based binder). This is referred to as a co-binder.

[0228] Examples of suitable auxiliary binders include: saturated polyester resins; polyvinyl acetate, polyvinyl butyrate, copolymers of vinyl acetate, vinyl isobutyl ether, copolymers of vinyl chloride and vinyl isobutyl ether, styrene copolymers such as styrene / butadiene copolymers, acrylic resins, hydroxy-acrylate copolymers, fatty acids and cyclized rubbers.

[0229] The coating composition of the present invention preferably comprises 0 to 10 wt % of an auxiliary binder, based on the total weight of the composition.

[0230] solvent

[0231] The coating composition of the present invention optionally comprises a solvent.

[0232] Suitable solvents include aromatic hydrocarbons, aliphatic hydrocarbons, ketones, esters, alcohols, and ethers.

[0233] Specific examples of suitable solvents include toluene, xylene, light aromatic hydrocarbon solvent naphtha (C8-C10, Solvesso 100), solvent oil, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), ethyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, ethanol, isopropyl alcohol, n-propyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, tert-butanol, benzyl alcohol, and propylene glycol methyl ether. A mixture of xylene and n-butanol is preferred.

[0234] A preferred coating composition of the present invention comprises a minimal amount of solvent as this reduces VOC.The coating composition preferably comprises 2-10 wt% solvent and more preferably 2-5 wt% solvent, based on the total weight of the composition.

[0235] additive

[0236] The coating compositions of the present invention optionally contain a variety of additives. Examples of additives that are optionally present in the compositions of the present invention include glass flakes, flake pigments (e.g., non-leafing aluminum), hydrocarbon resins, dehumidifiers, coloring pigments, additional anticorrosive pigments (e.g., zinc phosphate), anti-settling agents, desiccants, and plasticizers.

[0237] The amount of additional additives is preferably 0 to 10% by weight, more preferably 0.1-5% by weight, still more preferably 0.1 to 2.5% by weight and particularly preferably 0.2 to 2% by weight, based on the total weight of the coating composition.

[0238] Composition characteristics

[0239] A preferred coating composition of the present invention comprises:

[0240] (i) 5.0-10 wt %, more preferably 6.0-8.0 wt % of an epoxy adhesive;

[0241] (ii) 1.5-7.5 wt%, more preferably 2.0-5.0 wt% of an epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0242] (iii) 70-85 wt %, more preferably 75-80 wt % zinc dust;

[0243] (iv) 1.0-7.5 wt %, more preferably 2.0-4.0 wt % of a curing agent; and

[0244] (v) 0.1-2.0% by weight, more preferably 0.1-1.5% by weight, of aminoalkylalkoxysilane,

[0245] The composition has a solids content of at least 75% by volume and a VOC content of 10% by weight or less, based on the total volume and weight of the composition, respectively.

[0246] A further preferred coating composition of the present invention comprises:

[0247] (i) 5.0-10 wt %, more preferably 6.0-8.0 wt % of an epoxy adhesive;

[0248] (ii) 1.5-7.5 wt%, more preferably 2.0-5.0 wt% of an epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0249] (iii) 70-85 wt %, more preferably 75-80 wt % zinc dust;

[0250] (iv) 2.0-4.0 wt % of a curing agent;

[0251] (v) 0.1-2.0 wt %, more preferably 0.1-1.5 wt % of aminoalkylalkoxysilane; and

[0252] (vi) 3.0-6.0 wt% of fillers, such as microspheres,

[0253] The composition has a solids content of at least 75% by volume and a VOC content of 10% by weight or less, based on the total volume and weight of the composition, respectively.

[0254] A further preferred coating composition of the present invention comprises:

[0255] (i) 6.0-8.0 wt % of an epoxy adhesive;

[0256] (ii) 1.5-7.5 wt%, more preferably 2.0-5.0 wt% of an epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0257] (iii) 70-85 wt %, more preferably 75-80 wt % zinc dust;

[0258] (iv) 2.0-4.0 wt % of a curing agent;

[0259] (v) 0.1-2.0 wt %, more preferably 0.1-1.5 wt % of aminoalkylalkoxysilane;

[0260] (vi) 3.0-6.0 wt% of a filler, such as microspheres; and

[0261] (vii) 0.2-3.0 wt. % of a rheology modifier, based on the total volume and weight, respectively, of the composition.

[0262] A particularly preferred composition of the present invention comprises less than 5 wt%, more preferably less than 4 wt%, and still more preferably less than 3 wt% reactive diluent.An especially preferred coating composition is substantially free (eg, contains no) reactive diluent.

[0263] A preferred coating composition of the present invention has a solids content of at least 75% by volume, preferably at least 80% by volume and more preferably at least 85% by volume, based on the total volume of the composition.

[0264] A preferred coating composition of the present invention has a solids content of at least 90 wt. % and more preferably at least 95 wt. %, based on the total weight of the composition.

[0265] A preferred coating composition of the present invention has a VOC content of 0-10 wt%, preferably 0-7.5 wt% and more preferably 0-5 wt%, based on the total weight of the composition.

[0266] A preferred coating composition of the present invention has a VOC content of 175 g / L or less and more preferably 150 g / L or less.

[0267] A preferred coating composition of the present invention has a pigment volume concentration (PVC) of 50-60% and more preferably 52-56%.

[0268] A preferred coating composition of the present invention has a Stormer viscosity of 70-140 KU, preferably 80-135 KU and even more preferably 90-130 KU.

[0269] A preferred coating composition of the present invention has a viscosity of 100-600 mPas, preferably 200-500 mPas and even more preferably 300-450 mPas.

[0270] A preferred coating composition of the present invention is sprayable, and preferably is sprayable by airless spray. Preferably, the composition is sprayable using an airless spray pump having a pump ratio of at least 30:1, preferably at least 40:1. Preferably, the composition is sprayable using an airless spray pump having an inlet pressure of 0.2 to 0.8 MPa, more preferably 0.3 to 0.5 MPa. Preferably, the composition is sprayable using a hose length of up to 50 meters under one or both of the aforementioned conditions. Suitable nozzle types are Graco's 519, 521, 523, 619, 621, and 623. Corresponding nozzles are also available from other suppliers. The composition is preferably sprayable in a temperature range of -5°C to 40°C, preferably 5°C to 35°C.

[0271] Containers and Kits

[0272] The present invention also relates to a container containing the coating composition as described above.

[0273] Alternatively, the coating composition of the present invention may be provided in the form of a kit. A kit for preparing the composition as described above comprises:

[0274] (i) a first container containing an epoxy-based adhesive, epoxy silane (wherein the epoxy silane contains ethoxy groups and methoxy groups), and zinc (preferably zinc dust); and

[0275] (ii) A second container containing a curing agent and preferably, an aminoalkylalkoxysilane.

[0276] The mixture present in the first container is referred to herein as component A. The mixture present in the second container is referred to herein as component B. Preferably, the second container also contains a curing accelerator, ie, component B comprises a curing accelerator.

[0277] When present, fillers (eg, microspheres) may be present in either component A or component B. Preferably, however, the filler is present in component A.

[0278] When present, the rheology modifier may be present in either Component A or Component B. However, preferably, the rheology modifier is present in Component A.

[0279] When present, the leveling agent may be present in component A or component B. However, preferably, the leveling agent is present in component A.

[0280] When present, the defoamer may be present in either component A or component B. Preferably, however, the defoamer is present in component A.

[0281] When present, the dispersant may be present in either component A or component B. However, preferably, the dispersant is present in component A.

[0282] When present, the further binder may be present in either component A or component B. However, preferably, the further binder is present in component A.

[0283] When present, the solvent may be present in either component A or component B.

[0284] When present, the additive may be present in either component A or component B. However, preferably, the additive is present in component A.

[0285] When present, the reactive diluent is preferably present in component A.

[0286] Part B particularly preferably comprises (e.g., consists of) a curing agent, optionally an aminoalkylalkoxysilane, and optionally a curing accelerator. Part B preferably comprises (e.g., consists of) a polyamine curing agent, optionally an aminoalkylalkoxysilane, and a curing accelerator. The AHEW of part B is preferably 70-200 g / eq, more preferably 80-140 g / eq, and even more preferably 90-120 g / eq.

[0287] Preferably, component B comprises 60-85 wt % and more preferably 70-80 wt % of curing agent, based on the total weight of component B.

[0288] Preferably, component B comprises 10 to 30 wt. % and more preferably 15 to 25 wt. % of aminoalkylalkoxysilane, based on the total weight of component B.

[0289] Preferably, component B comprises 1-10 wt % and more preferably 1.5 to 5 wt % of a curing accelerator, based on the total weight of component B.

[0290] Particularly preferably, component A comprises:

[0291] Epoxy-based adhesive; epoxy silane, wherein the epoxy silane contains ethoxy and methoxy groups; zinc, preferably zinc dust; filler, such as microspheres; rheology modifier; leveling agent; defoamer; dispersant; other adhesives; solvent; and / or additives.

[0292] Preferably, component A comprises 3-15 wt %, more preferably 5-10 wt %, and still more preferably 6-8 wt % of the epoxy-based adhesive based on the total weight of component A.

[0293] Preferably, component A comprises 1-10 wt%, more preferably 4.5-7.5 wt%, and still more preferably 2.0-5.0 wt% of epoxy silane based on the total weight of component A, wherein the epoxy silane comprises ethoxy and methoxy groups.

[0294] Preferably, component A comprises 65-90 wt %, more preferably 70-85 wt % and still more preferably 75-82 wt % zinc, based on the total weight of component A.

[0295] Preferably, component A comprises 2.0-10 wt %, more preferably 3.0-8.0 wt %, and still more preferably 3.0-6.0 wt % of filler (eg, microspheres), based on the total weight of component A.

[0296] Preferably, component A comprises 0-5.0 wt. %, more preferably 0.2-3.0 wt. %, and still more preferably 0.3-2.0 wt. % of the rheology modifier, based on the total weight of component A.

[0297] Preferably, component A comprises 0-5 wt %, more preferably 0.1-2.5 wt % and still more preferably 0.2-1.0 wt % of a leveling agent, based on the total weight of component A.

[0298] Preferably, component A comprises 0 to 1.0 wt. % and more preferably 0.1 to 0.2 wt. % of defoaming agent, based on the total weight of component A.

[0299] Preferably, component A comprises 0 to 1.5 wt % and more preferably 0.1 to 1 wt % of dispersant, based on the total weight of component A.

[0300] Preferably, component A comprises 0-10 wt % of an auxiliary binder, based on the total weight of component A.

[0301] Preferably, component A comprises 2-10 wt % and more preferably 2-5 wt % of solvent, based on the total weight of component A.

[0302] Preferably, component A comprises 0-5 wt %, more preferably 0.1-4 wt % and still more preferably 0.5-3 wt % of reactive diluent, based on the total weight of component A.

[0303] manufacture

[0304] The present invention also relates to a method for preparing the composition as described above, comprising mixing:

[0305] (i) Epoxy adhesives;

[0306] (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups;

[0307] (iii) zinc, preferably zinc dust;

[0308] (iv) a curing agent; and

[0309] (v) Preferably, aminoalkylalkoxysilane.

[0310] In a preferred method of the present invention, the epoxy adhesive, epoxy silane, and zinc are premixed (i.e., as Component A), and the curing agent, and, if present, the accelerator and aminoalkylalkoxysilane are mixed separately (i.e., as Component B). Preferably, a filler (e.g., microspheres) is added to the epoxy adhesive, epoxy silane, and zinc mixture. Preferably, the other ingredients described herein (present in Component A of the kit) are added to the epoxy adhesive, epoxy silane, and zinc mixture. Preferably, the two resulting mixtures are combined (e.g., immediately before use) and mixed. Any conventional mixing equipment can be used.

[0311] Apply to the surface

[0312] The present invention also relates to a method of providing a coating on a surface, wherein the method comprises:

[0313] (i) applying the composition as described above; and

[0314] (ii) drying and / or curing the composition to form a coating on the surface.

[0315] Optionally, the surface is pretreated before applying the coating composition of the present invention. Preferably, the coating composition is applied directly to the surface. This means that the coating composition comprising zinc is in direct contact with the surface.

[0316] The coating composition of the present invention can be part of a coating system. In a preferred coating system, the coating composition of the present invention is applied directly to a surface and then another coating, such as an epoxy coating, is applied thereto. Preferably, the coating of the present invention is a primer.

[0317] The coating composition of the present invention can be applied to the substrate by any conventional coating method (e.g., spraying, roller coating, dipping, etc.). Preferably, the coating composition is applied by spraying and more preferably by airless spraying. Spraying is preferred because it enables coating of large surface areas in a uniform manner. In addition, spraying can be used to coat non-horizontal surfaces.

[0318] Preferably, the coating is applied using an airless spray pump having a pump ratio of at least 30:1, and preferably at least 40:1. Preferably, the coating is applied using an airless spray pump having an inlet air pressure of 0.2 to 0.8 MPa, and more preferably 0.3 to 0.5 MPa. Preferably, the coating is applied using a hose length of up to 50 meters using one or both of the above conditions. Suitable nozzle types include Graco's 519, 521, 523, 619, 621, and 623. Corresponding types are also available from other suppliers. Application of the coating composition is preferably carried out at a temperature range of -5°C to 40°C, preferably 5°C to 35°C.

[0319] Preferably, the substrate is metal, in particular steel.

[0320] Preferably, the wet film thickness of the coating is 40-90 μm and more preferably 50 to 85 μm.The relatively low viscosity of the coating composition of the present invention makes it possible to prepare relatively thin wet films.

[0321] The present invention also relates to a coating comprising a coating composition as described above. Optionally, the coating is applied in multiple steps, wherein a first layer of coating is applied, dried and cured, and then subsequent layers of coating are applied.

[0322] The coating compositions of the present invention can be used to form a single-layer coating or a multi-layer coating (i.e., a coating system). In the case of a multi-layer coating, the coating compositions of the present invention are preferably used to form a first layer on a substrate (e.g., a metal surface). Preferably, a second coating layer is applied.

[0323] Curing

[0324] The coatings of the present invention are preferably cured. Thus, once a substrate (e.g., a metal substrate) is coated with the coating composition of the present invention, the coating is preferably cured. Preferably, the coatings of the present invention cure under ambient conditions, for example, within a temperature range of -5°C to 50°C. Thus, preferably, the coatings of the present invention do not require heat to cause curing. Preferably, the cure time (i.e., the time to achieve surface dryness as determined by the thumb test) at ambient temperature (20°C to 40°C) is 0.5 to 20 hours, more preferably 2 to 10 hours, and even more preferably 2 to 8 hours.

[0325] Coatings and products

[0326] The present invention also relates to a substrate coated with a coating composition as described above or a coating as described above. The coating composition of the present invention can be applied to any substrate. Representative examples of substrates include metal substrates, and in particular steel, galvanized steel, stainless steel, aluminum and copper. Particularly preferably, the substrate is steel.

[0327] The coatings of the present invention provide an anticorrosive coating on such substrates. Therefore, preferred types of metal substrates coated with the coatings of the present invention are those that come into contact with corrosive environments. Examples of metal substrates include bridges, oil rigs, steel infrastructure, pipelines, valves, tanks, containers, ship components, and the like. A particularly preferred substrate is a bridge, oil rig, or steel infrastructure.

[0328] The substrate may be partially or fully coated with the coating composition or coating of the present invention. However, preferably, all substrates (eg, all exterior walls) are coated with the coating composition or coating of the present invention.

[0329] Preferably, the coating comprises at least 80 wt. %, preferably at least 85 wt. %, of zinc dust, based on the total weight of the dry coating.

[0330] Preferred coatings have a dry thickness of 40-90 μm and more preferably 50 to 85 μm.

[0331] coating system

[0332] The present invention preferably provides a composition that is a zinc primer. Zinc primers are used for corrosion protection of steel structures (such as bridges, infrastructure, buildings, platforms, and power plants) using zinc plating. Zinc primers act as sacrificial anodes in galvanizing systems and therefore rely on direct contact with the steel. Therefore, the zinc primer is preferably the first layer in the coating system.

[0333] A coating system for zinc corrosion protection preferably includes or consists of three layers: a zinc primer layer, a midcoat layer, and a topcoat layer. The midcoat layer is preferably epoxy-based. The topcoat layer is preferably polyurethane or polysiloxane-based. Together, the coatings in the system provide both zinc protection and barrier protection for the steel substrate.

[0334] use

[0335] The present invention also provides a use of the composition as described above for forming a coating (preferably an anti-corrosion coating) on ​​at least one surface of an article. Preferably, the surface is a metal surface as described above.

[0336] The invention will now be described with reference to the following non-limiting examples.

[0337] Example

[0338] Material

[0339] The compounds used in the examples are all commercially available and are summarized in the table below.

[0340] Table 1: Compounds used in the examples.

[0341]

[0342] * Combined as “Additives” in Tables 2-4.

[0343] Preparation of composition

[0344] EXAMPLES Compositions were prepared by conventional techniques for paint production.

[0345] The composition was prepared as a two-component mixture (i.e., component A and component B). Component A was prepared by mixing the adhesive, epoxy silane, and solvent in a tank under low-speed stirring for 5 minutes. Additives, dispersants, and rheology modifiers were then added and mixed for an additional 5 minutes under high stirring speed. Zinc dust was added and the composition was mixed at high speed for 10 minutes. Finally, the microspheres and additional solvent were added and stirred at medium speed for 5 minutes.

[0346] In a separate pot, prepare Part B by combining the curing agent, aminoalkylalkoxysilane, and accelerator and shaking for 3 minutes.

[0347] The two components A and B are then mixed at the time of use.

[0348] The compositions prepared are summarized in the following table.Unless otherwise stated, all weight % specified herein are based on the total mixed composition.

[0349] Comparative compositions (herein CE) were prepared in a similar manner.

[0350] Preparation of samples for testing and test methods

[0351] Calculate PVC and Volume % Solids

[0352] According to ISO 4618-1:2018, PVC is the ratio of the volume of pigments and other solid particles in a product to the total volume of non-volatile matter.

[0353] To be able to calculate the pigment volume concentration (PVC) of a paint from a recipe expressed as a weight fraction, the non-volatile matter content and density of each component of the paint are required. From these parameters, the approximate volume of each component in the paint can be calculated.

[0354] Use the following formula to calculate PVC (European Coatings Handbook, Brock, Groteklaes and Mischke, Vincentz Verlag 2010)

[0355] PVC [%] =

[0356]

[0357] Calculate the volume % solids using the following formula:

[0358] Volume = (weight / density)

[0359] Volume % of solids =

[0360] Calculation of Volatile Organic Compounds (VOC)

[0361] The volatile organic compound (VOC) (g / L) of the coating composition is calculated as follows:

[0362] VOC [g / L] =

[0363] Viscosity, KU

[0364] The consistency of the coating composition was determined using a digital Stormer viscometer according to ASTM D562-10:2018 Method B. The measurement was performed at 23° C. on samples in 500 mL containers.

[0365] Viscosity, cone and plate method

[0366] Viscosity according to ISO 2884-1:2006 at 23°C and 10000 s -1 Measured at a shear rate of .

[0367] Storage stability

[0368] The samples were stored in sealed containers at 50°C for 4 weeks. The viscosity (KU and cone-plate) was measured before and after storage. If the cone-plate viscosity doubled and the KU viscosity exceeded 140 KU after the storage test period, the storage stability test failed.

[0369] Airless spray

[0370] The composition was applied by airless spray using an airless spray pump (Graco Merkur G48, pump ratio 48:1, inlet air pressure 0.3-0.5 MPa, nozzles Graco 519, 521, 523, 619, 621, and 623). The spray pattern of the composition was visually observed. Observation of "fingering" or "tailing" in the spray pattern was considered a failure because such defects would result in uneven film formation. Dry spraying was also considered a failure because it would result in little or no flow and leveling in the applied paint.

[0371] The appearance of the wet and dry films was checked. If the spray pattern showed no fingers or tails and no dry spray occurred, a uniform, level film with no orange peel was obtained and the composition was considered to have passed the test.

[0372] If the composition must be diluted more than 5% to pass the above criteria, it fails the airless spray test.

[0373] Drying time

[0374] The coating composition was applied to a glass plate using an applicator with a 200 μm gap, and drying time was assessed manually using the thumb. The coated glass plate was immediately placed in a climate chamber maintained at 5°C, 85% RH, and 23°C, 60% RH. The drying state of the coating film was assessed every 1-2 hours according to ASTM D1640-03, "Standard Test Method for Drying, Curing, or Film Formation of Organic Coatings at Room Temperature."

[0375] Preparation of samples for accelerated corrosion testing

[0376] The accelerated corrosion test was performed by applying the coating composition to a steel substrate having a cleanliness level corresponding to Sa 2.5 by airless spraying at a temperature of 23° C. and a relative humidity of 60-80%. The zinc-rich coating composition was applied to a wet film thickness resulting in a dry film thickness of 60-100 μm. The applied coating was cooled to room temperature (23° C.) before exposure to the test conditions. o C, 60-80% RH) and dried and cured for 14 days.

[0377] The salt spray test was performed in a neutral salt spray at 35 ± 2 °C according to ISO 9227:2012 “Corrosion tests in artificial atmospheres – Salt spray test”.

[0378] • The continuous condensation test was performed at 38 ± 2 °C according to ISO 6270-1:1998 “Paints and varnishes — Determination of resistance to humidity — Part 1: Continuous condensation”.

[0379] result

[0380] Table 2: Sprayability and storage stability results

[0381]

[0382] The results in Table 1 show that the compositions containing ethoxy-functional epoxysilanes have higher stability than the compositions containing methoxy-functional epoxysilanes. The comparative composition containing 0.3 wt.% alkoxy-functional epoxysilane in component A (CE4) has significantly worse performance. The prior art compositions cannot be sprayed at all due to their high viscosity.

[0383] The results in Table 2 show that the nature of the alkoxy functionality in the epoxysilane has a significant impact on drying and curing times. Compositions containing methoxy-functional epoxysilanes have faster drying and curing times than compositions containing ethoxy-functional epoxysilanes. It has also been found that the presence of aminoalkylmethoxysilane in component B can also improve curing speed (see the results of Example 1 relative to Example 2).

[0384] Combinations comprising a mixture of methoxy- and ethoxy-functional epoxy silanes in component A and aminoalkylalkoxysilanes in component B provide an optimal balance between sprayability, storage stability, and drying and curing times.

[0385] The results in Table 3 show that the coatings formed from the compositions of the present invention have strong anti-corrosion properties. Specifically, these coatings passed all the different anti-corrosion tests applied to them.

[0386] Thus, the compositions of the present invention have a high volume solids content and a low VOC content, but are sprayable (without any dilution) and have an acceptable viscosity. These compositions are also storage stable and dry and cure quickly. The resulting coatings have strong anti-corrosion properties.

[0387] Table 3: Drying and curing times

[0388]

[0389]

[0390] Table 4: Corrosion Test

[0391]

Claims

1. A coating composition, preferably a primer, comprising: (i) Epoxy adhesives; (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups; (iii) zinc, preferably zinc dust; (iv) a curing agent; and (v) preferably, aminoalkylalkoxysilane, wherein the solids content of the composition is at least 75% by volume and the VOC content of the composition is 10% by weight or less, based on the total volume and weight of the composition, respectively.

2. The composition of claim 1 comprising a mixture of epoxy silanes.

3. The composition according to claim 1 or 2, wherein the epoxy silane is a 3-glycidyloxyalkylalkoxysilane, preferably a 3-glycidyloxypropylalkoxysilane.

4. The composition of any preceding claim, wherein the epoxy silane comprises 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane.

5. A composition according to any preceding claim, wherein The total amount of zinc present in the coating composition is preferably 65-90 wt%, more preferably 70-85 wt% and even more preferably 75-80 wt%, based on the total weight of the composition.

6. A composition according to any preceding claim, wherein the curing agent comprises at least one benzylamine moiety: 。 7. A composition according to any preceding claim comprising an aminoalkylalkoxysilane, preferably an aminopropylalkoxysilane.

8. A composition according to any preceding claim which does not comprise a reactive diluent.

9. A composition according to any preceding claim having at least one, preferably at least two, more preferably at least three and still more preferably all of the following: - a solids content of at least 80% by volume, based on the total volume of the composition; - a solids content of at least 90% by weight and more preferably at least 95% by weight, based on the total weight of the composition; - a VOC content of 0-10% by weight, preferably 0-7.5% by weight and more preferably 0-5% by weight, based on the total weight of the composition; - a VOC content of 175 g / L or less and more preferably 150 g / L or less, - a pigment volume concentration (PVC) of 50-60% and more preferably 52-56%, - a Stormer viscosity of 70-140 KU, preferably 80-135 KU and even more preferably 90-130 KU; and / or - a viscosity of 100-600 mPas, preferably 200-500 mPas and even more preferably 300-450 mPas.

10. A method for preparing a composition according to any preceding claim, the method comprising mixing: (i) Epoxy adhesives; (ii) epoxy silane, wherein the epoxy silane comprises ethoxy and methoxy groups; (iii) zinc, preferably zinc dust; (iv) a curing agent; and (v) Preferably, aminoalkylalkoxysilane.

11. A kit for preparing the composition according to any one of claims 1 to 9, comprising: (i) a first container containing an epoxy adhesive, epoxy silane, and zinc, preferably zinc dust, wherein the epoxy silane contains ethoxy and methoxy groups; and (ii) a second container containing a curing agent and preferably, an aminoalkylalkoxysilane.

12. A container containing the composition according to any one of claims 1 to 9.

13. A method of providing a coating on a surface, wherein the method comprises: (i) applying the composition according to any one of claims 1 to 9; as well as (ii) drying and / or curing the composition to form a coating on the surface.

14. A coating on a surface, wherein the coating comprises or is derived from the composition of any one of claims 1 to 9.

15. Use of the composition according to any one of claims 1 to 9 for forming a coating on at least one surface of an article.

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