Coating

Abstract

A multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B directly thereon wherein: (i) the coating layer A comprises or is formed from an intumescent coating composition comprising a) a binder; and (ii) the coating layer B comprises or is formed from a non-intumescent coating composition comprising a) a binder; and b) fibers.

Description

Technical Field

[0001] The present invention relates to a multilayer intumescent coating system comprising an intumescent coating layer A and an adjacent non-intumescent coating layer B. The intumescent coating system of the present invention significantly reduces char failures and thus provides improved fire protection. The present invention also relates to a method for applying the coating system to a substrate. The present invention also relates to a substrate coated with the intumescent coating system. Background Art

[0002] Steel is commonly used as a building material and offers many advantages. However, it is known that, if unprotected, structural steel can quickly lose its structural integrity in the event of a fire. Therefore, it is known to protect steel using some form of passive fire protection, of which intumescent coatings are a known variant. Passive fire protection is designed to slow the rate at which the temperature of the structural steel rises, significantly delaying any structural collapse, allowing time to evacuate personnel and protect expensive assets.

[0003] Intumescent coatings are defined as coatings that expand in the event of a fire to produce a carbon-based insulating char, and have a number of advantages over other available forms of passive fire protection, such as their light weight and environmental durability.

[0004] One problem with intumescent coatings is that the char can become brittle, leading to cracking, which exposes the substrate. The substrate then reaches critical temperatures earlier than if the char had not cracked, causing the substrate's structural integrity to collapse earlier. Certain structures, such as hollow sections, are more difficult to protect. Almost all intumescent products exhibit signs of stress caused by expansion and contraction in hollow sections of the substrate, resulting in long tears or cracks in the char, which expose the steel and limit performance. For example, this cracking of the char can occur in hydrocarbon pool flames, jet flames, or cellulose flames. To mitigate these issues, a mesh, such as a fabric or metal mesh, is often embedded within the intumescent coating to hold the char together and prolong the coating's performance. The mesh can contain weaknesses created by cracking and movement. The mesh can be applied around the entire profile or, sometimes, only around flanges or joints. However, there are several challenges associated with using mesh. For example, the mesh must be cut to size for specific steel dimensions, and the mesh applicator must follow the sprayer to position the mesh and roll it while the product is still wet. Solvents are also used on the roller to simplify rolling, which can lead to VOC emissions issues. Applying the mesh is a very resource-intensive process and requires applicator training to avoid improper mesh application. The present invention seeks to avoid the use of mesh. Therefore, in one embodiment, the multi-layer intumescent coating system of the present invention does not include a mesh layer.

[0005] Intumescent coating systems that do not contain textile meshes are known in the literature. US2016 / 0168393 describes the use of multi-layer intumescent coatings with different binder technologies to stabilize chars. Different chars are formed using different binder technologies, and the chars are allegedly stabilized because the chars from one binder technology fill the pores in the chars from another binder technology. However, this solution presents potential problems with interlayer adhesion. Using such a diverse set of technologies is also complex and costly.

[0006] US5989706 describes the use of two different intumescent layers having different char densities. The first component forms a rigid char that protects the substrate from breakthrough, and the second component forms an insulating char that protects the substrate from conductive, radiative, and / or convective heating under fire conditions.

[0007] WO2022 / 117878 describes an intumescent coating system comprising an intumescent coating layer comprising an epoxy binder and a curing agent for the binder, and a topcoat layer comprising an acrylic, polyurethane, or silicone binder derived from aqueous starting materials. No non-intumescent coating layer comprising a binder and fibers is present.

[0008] US 2011 / 274863 describes a fire-resistant insulation tape composition for aircraft construction. This document does not mention coatings or applying coatings to substrates.

[0009] The present inventors have now discovered that by applying a non-intumescent coating composition containing fibers on top of an intumescent coating layer, the char formed by the intumescent coating layer is stabilized and prevented from cracking or falling off. The intumescent coating system allows for improved efficiency of existing or new products by using a non-intumescent coating layer instead of optimizing the intumescent coating layer itself. The intumescent coating system described herein is easier to apply than coating systems employing traditional meshes and outperforms known coatings. The fibers required in the non-intumescent layer act as a "mesh" within the coating layer, supporting the char in the intumescent layer and preventing it from cracking. Summary of the Invention

[0010] Thus, viewed from one aspect, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B directly thereon, wherein:

[0011] (i) coating layer A comprises a) a binder; and

[0012] (ii) coating layer B comprises, such as consists of, or is formed from a non-intumescent coating composition comprising:

[0013] a) adhesive; and

[0014] b) Fiber.

[0015] Viewed alternatively, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B directly thereon, wherein:

[0016] (i) coating layer A comprises, such as consists of, or is formed from an intumescent coating composition comprising:

[0017] a) adhesives;

[0018] b) an acid generating agent; and

[0019] c) expansion agent; and

[0020] (ii) coating layer B comprises, such as consists of, or is formed from a non-intumescent coating composition comprising:

[0021] a) adhesive; and

[0022] b) Fiber.

[0023] Viewed alternatively, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B directly thereon, wherein:

[0024] (i) The coating layer A comprises or is formed from the following:

[0025] a) adhesives;

[0026] b) acid generators; and

[0027] c) a swelling agent; and

[0028] (ii) The coating layer B comprises or consists of:

[0029] a) adhesive; and

[0030] b) Fiber.

[0031] In one embodiment, the multi-layer intumescent coating system comprises a second intumescent coating layer C applied directly onto layer B. Preferably, coating layer C comprises, such as consists of (or is formed from) an intumescent coating composition C comprising:

[0032] a) adhesives;

[0033] b) acid generators; and

[0034] c) expansion agent.

[0035] In one embodiment, coating layer C has the same composition as coating layer A.

[0036] Coating layer B is applied directly onto coating layer A, and optional coating layer C is applied directly onto coating layer B. Thus, there are no intervening layers between layers A, B, and C. Coating layer A should be closest to the substrate being coated.

[0037] The coating layer B is non-intumescent and therefore does not significantly expand and does not form carbonaceous char when exposed to heat or fire. It is therefore preferably free of components that form intumescent coatings, i.e., a combination of an acid generator and an intumescent agent.

[0038] In one embodiment, the multi-layer intumescent coating system does not comprise a mesh.

[0039] Viewed from another aspect the invention provides a substrate coated with an intumescent coating system as hereinbefore defined.The substrate may be provided with a primer coating as is known in the art.

[0040] Viewed from another aspect, the invention provides a method for applying a multilayer intumescent coating system as hereinbefore defined to a substrate, the method comprising applying coating layer A to the substrate and applying coating layer B directly on top of layer A.

[0041] Viewed from another aspect, the invention provides a method for applying a multilayer intumescent coating system as hereinbefore defined to a substrate, the method comprising applying an intumescent coating composition A to the substrate and optionally curing the composition to form coating layer A;

[0042] and applying a non-intumescent coating composition B directly onto the coating layer A, and optionally curing the composition to form the coating layer B.

[0043] Viewed from another aspect the invention provides the use of an intumescent coating system as hereinbefore defined for protecting a substrate from fire.

[0044] definition

[0045] The present invention relates to an intumescent coating system. The term intumescent coating system defines a multilayer coating system comprising at least an intumescent coating layer A and a non-intumescent coating layer B. The intumescent coating system may further comprise a third layer C, which is intumescent. Thus, the intumescent coating system of the present invention may comprise at least two or three layers. For example, for aesthetic reasons, a topcoat may be applied over the intumescent coating system of the present invention.

[0046] The term intumescent coating composition defines the composition used to prepare intumescent coating layer A and, optionally, layer C. The term non-intumescent coating composition defines the composition used to prepare non-intumescent coating layer B. Thus, it will be understood that coating layers A, B, and C ideally consist of the components of the respective intumescent coating compositions A, B, and C. It will also be understood that in the final, multi-layer intumescent coating system, any organic solvent or water present to allow application of the intumescent coating compositions A, B, and C to the substrate will evaporate. The layers of the intumescent coating system may also cure. Thus, when wt% values ​​are given herein for an intumescent or non-intumescent coating composition, these percentages also apply to the intumescent or non-intumescent coating layers, as these layers are formed from the respective compositions.

[0047] The intumescent coating composition contains components that ensure expansion. The intumescent components are an acid generator and an intumescent agent. Optionally, the coating composition contains a specific carbon source as an intumescent component.

[0048] "Intumescent" means charring and expanding. For example, when exposed to heat from a fire, the components in the intumescent coating chemically react to produce gases and a cellular carbonaceous char. As the gases become trapped in the char, the cellular carbonaceous char expands into foam. As a result, the intumescent coating forms a relatively thick and insulating foam barrier on the surface of a coated substrate exposed to the heat from a fire.

[0049] As used herein, the term "expansion" is used in relation to intumescent coatings and refers to a measure of the increase in volume of the coating upon contact with heat from a fire. It is preferably determined by measuring the char depth using a char depth gauge / hydrocone.

[0050] Non-intumescent coating layers derived from non-intumescent coating compositions do not significantly expand when exposed to heat from a fire and do not form carbonaceous chars. Non-intumescent layers should not contain a combination of an acid generator and an intumescent agent. They do not expand when exposed to heat from a fire.

[0051] The term expansion agent is used interchangeably with the term blowing agent herein.

[0052] The term acid generating compound may also be referred to herein as an acid catalyst.

[0053] As used herein, the term "binder" refers to a polymer that forms a continuous film on a substrate surface when applied to the substrate surface. The binder can be physically dried or cured using a curing agent and optionally a cross-linking agent.

[0054] As used herein, the term "epoxy-based adhesive system" refers to a combination of one or more epoxy resins and one or more curing agents, and optionally reactive epoxy diluents, silanes, accelerators (promoters), and hydrocarbon resins.

[0055] As used herein, the term "curing agent" refers to a compound that, when mixed with an adhesive, such as an epoxy-based adhesive, produces a cured or hardened coating by creating crosslinks within the polymer. Sometimes, a curing agent is also referred to as a hardener.

[0056] The term (meth)acrylate encompasses both methacrylates and acrylates.

[0057] In the present invention, the term "dispersion" refers to both particles and droplets (emulsion) dispersed in water.

[0058] In a preferred embodiment, the intumescent coating system is overcoated with a top coat. The top coat can provide the desired color to the substrate and enhance the durability of the intumescent coating system. Transparent top coats may also be suitable. The top coat preferably does not contain fibers. Thus, they are easily distinguishable from the non-intumescent layer B.

[0059] In another preferred embodiment, the intumescent coating system is not overcoated with a topcoat.

[0060] In one embodiment, the intumescent coating layer A is present directly on the substrate. In another embodiment, the intumescent coating layer A is present on an anti-corrosion primer layer, such as an epoxy layer, on the substrate. DETAILED DESCRIPTION

[0061] The present invention relates to an intumescent coating system for a substrate such as a metal substrate or a composite material or a cellulosic substrate, preferably a steel substrate. The substrate may be present on any object on which the coating system of the present invention may be useful.

[0062] The substrate can be an offshore or onshore oil and gas facility, a wind turbine, a chimney, a power station or other industrial installation, a bridge, a crane, a high-value infrastructure such as a hotel, a hospital, an airport, a stadium, an office building, etc.

[0063] The substrate can be provided with a conventional anti-corrosion primer coating, to which the intumescent coating layer A is adhered. Examples of suitable primer layers include coatings based on epoxy resins, modified epoxy resins (such as those modified with polyvinyl butyral), polyurethanes, acrylics, vinyls, and chlorinated rubber. Preferably, the primer layer is an epoxy-based primer or a zinc-rich epoxy-based primer. The dry film thickness of the primer is ideally in the range of 15-500 μm.

[0064] The intumescent coating layer A can also be applied directly to a substrate, for example directly to metal.

[0065] The intumescent coating system (i.e., layer A and layer B or layer A, layer B and layer C as defined herein) can be applied at a high dry film thickness to ensure good fire protection. The dry film thickness of the intumescent layer A is preferably from 150 μm to 10,000 μm, preferably from 200 μm to 8,000 μm, more preferably from 500 μm to 4,000 μm.

[0066] The dry film thickness of the non-intumescent layer B is preferably less than 2000 μm, more preferably less than 1500 μm, and even more preferably less than 1000 μm. In some embodiments, the dry film thickness of the non-intumescent layer B is greater than 25 μm, preferably greater than 50 μm, and even more preferably greater than 100 μm. The dry film thickness of the non-intumescent layer B is preferably from 100 μm to 1500 μm, and even more preferably from 200 μm to 1000 μm.

[0067] In a preferred option, the dry film thickness of the non-intumescent layer B is preferably less than 500 μm, more preferably less than 400 μm, and further preferably less than 300 μm.

[0068] In a particularly preferred embodiment, the dry film thickness of the non-intumescent layer B is less than 200 μm.

[0069] The ratio between the dry film thickness of the intumescent layer A and the non-intumescent layer B may be from 1:1 to 1:0.05, preferably from 1:0.6 to 1:0.1.

[0070] The dry film thickness of the optional intumescent layer C is preferably 150 to 10,000 μm, more preferably 200 to 8,000 μm. The total dry film thickness of the intumescent layer A, the non-intumescent layer B and the optional intumescent layer C is preferably 500 to 20,000 μm, more preferably 1,000 to 16,000 μm.

[0071] In one embodiment, the dry film thickness of intumescent layer C is 0.2 to 3.0 times the thickness of intumescent layer A.

[0072] The colour of the non-intumescent layer B may be different from the colour of the intumescent coating layer A. This allows easy confirmation of the presence of layer B and therefore easy verification of the DFT (dry film thickness) of the non-intumescent layer B using a standard DFT meter.

[0073] Topcoats used for exterior intumescent coating systems can be based on polyurethanes, polysiloxanes, epoxies, alkyds, acrylics, vinyls, and chlorinated rubbers. Preferably, the topcoat is based on acrylics, polysiloxanes, or polyurethanes. Preferably, the topcoat is not based on vinyl esters, particularly not vinyl acetate. The thickness of the decorative topcoat can vary from 15 μm to 250 μm. Preferably, the thickness should be in the range of 25 μm to 100 μm, as excessive topcoat thickness may inhibit the intumescent reaction.

[0074] In another preferred embodiment, the intumescent coating system does not comprise a topcoat.

[0075] The intumescent coating system of the present invention is designed to protect substrates to a critical core temperature in the range of 200-750°C, depending on the nature of the substrate, the degree of loading, and the specific requirements of the particular structure being protected. The critical core temperature is generally defined as the temperature at which a particular substrate has lost its load-bearing capacity to the point where the structure is at imminent risk of critical collapse.

[0076] Intumescent coating composition

[0077] Intumescent coating layer A is prepared by applying an intumescent coating composition to a substrate. Intumescent coating layer C is prepared by applying an intumescent coating composition to layer B. This layer C may be the same as or different from layer A, but the following description of the intumescent coating composition applies to both layers A and C.

[0078] Preferably, layer C has the same composition as layer A.

[0079] The intumescent coating composition comprises a binder.

[0080] The intumescent coating composition comprises a binder, an intumescent component, and may contain conventional intumescent coating components such as pigments, fillers, and standard additives. The intumescent component includes an acid generator, which typically decomposes at elevated temperatures (e.g., greater than 200°C) to produce an acid that reacts with a carbon donor compound to form a carbonaceous char. The intumescent component also includes an expander, which decomposes at elevated temperatures (e.g., greater than 200°C) to produce a gas that expands the volume of the carbonaceous char and produces a carbonaceous foam.

[0081] The intumescent coating composition of the present invention may contain a specific carbon donor compound that acts as a charring agent, or the binder may act as the carbon donor.

[0082] In a preferred embodiment, the intumescent coating composition comprises a specific carbon donor compound as described in detail below.

[0083] When the intumescent coating is exposed to fire or heat, and the temperature of the intumescent coating exceeds 200°C, for example, the acid generator decomposes to provide acid. The carbon donor compound reacts with the acid to form a carbonaceous char. For example, ammonium polyphosphate (AMPP) acid generator decomposes at approximately 240°C to form ammonia and phosphoric acid. Phosphoric acid can be used as an acid for the dehydration reaction of an organic polyol compound, such as starch, cellulose, a non-polymeric sugar (e.g., glucose, fructose, sucrose, etc.), pentaerythritol, dipentaerythritol, or tripentaerythritol, or any combination thereof, which serves as the carbon donor compound.

[0084] Phosphoric acid reacts with hydroxyl groups to form a thermally unstable phosphate ester, which decomposes to release carbon dioxide and regenerate phosphoric acid. The dehydrated carbon donor and / or binder system forms a carbonaceous char, and the carbon dioxide expands the char into a foam.

[0085] The expansion agent also decomposes at elevated temperatures (eg, above 200° C.) and produces additional gas, which expands the volume of the carbonaceous char and produces a carbonaceous foam.

[0086] Therefore, it is preferred that the intumescent coating composition of the present invention comprises an acid generator, an intumescent agent and optionally a specific carbon donor compound.The binder may also act as a carbon donor.

[0087] Intumescent coating compositions may be solvent-free, solvent-borne, or water-borne.

[0088] Any organic solvent or water evaporates, leaving behind a dry, multi-layer intumescent coating system wherein layer A contains the solid components of the intumescent coating composition, layer B contains the solid components of the non-intumescent coating composition, and so on.

[0089] The intumescent coating composition of the present invention adheres well to both the substrate and the primer layer on the substrate and provides good water resistance and rapid hardness.

[0090] When exposed to heat from a fire, the intumescent coating layer preferably expands by more than 1.5 times, such as at least 5 times, for example 6 to 80 times, the volume of the coating layer.

[0091] The intumescent coating composition preferably comprises 11 wt.% or more of the acid generator, further preferably 15 wt.% or more, based on the total dry weight of the coating composition.

[0092] The intumescent coating composition preferably comprises 1.5 wt.% or more of an intumescent agent.

[0093] The intumescent coating composition preferably comprises 11 wt.% or more of an acid generator, based on the total dry weight of the coating composition, in combination with 1.5 wt.% or more of an intumescent agent, based on the total dry weight of the coating composition.

[0094] Non-intumescent coating compositions

[0095] Non-intumescent coating layer B is prepared by applying non-intumescent coating composition B to coating layer A. The non-intumescent coating composition comprises a binder and fibers. It should be understood that non-intumescent coating composition B is different from intumescent coating composition A. It should be understood that non-intumescent coating layer B is different from intumescent coating layer A.

[0096] Upon exposure to heat from a fire, the non-intumescent coating layer preferably expands less than 1.5 times, preferably less than 1.3 times, more preferably less than 1.1 times the volume of the coating layer.

[0097] In a preferred embodiment, the non-intumescent coating layer does not expand when exposed to heat from a fire.

[0098] The non-intumescent coating composition preferably comprises less than 10 wt.% of an acid generator, more preferably less than 5 wt.%, and even more preferably less than 2.5 wt.%, based on the total dry weight of the coating composition.

[0099] The non-intumescent coating composition preferably comprises less than 1.5 wt.% intumescent agent, more preferably less than 1.0 wt.% intumescent agent, further preferably less than 0.5 wt.% intumescent agent, based on the total dry weight of the coating composition.

[0100] The non-intumescent coating composition preferably comprises less than 10 wt.% acid generator combined with less than 1.5 wt.% intumescent agent, preferably less than 5 wt.% acid generator combined with less than 1.0 wt.% intumescent agent, based on the total dry weight of the coating composition.

[0101] In a preferred embodiment, the non-intumescent coating composition does not comprise a combination of an acid generator and an intumescent agent.

[0102] Non-intumescent coatings may contain conventional coating components such as pigments, fillers, and standard additives.

[0103] Non-intumescent coating compositions may be solvent-free, solvent-borne, or water-borne.

[0104] The non-intumescent coating compositions of the present invention adhere well to intumescent coating compositions.A particular feature of the present invention is the strong intercoat adhesion between the layers.

[0105] The components of the intumescent and non-intumescent coating compositions will now be described in more detail.

[0106] Adhesives

[0107] Any suitable binder may be used in the intumescent or non-intumescent coating. One skilled in the art can adjust the intumescent and non-intumescent coating compositions accordingly depending on the binder used, for example whether a curing agent is required.

[0108] Examples of suitable binders are vinyl-based binders, polyvinyl ester-based binders, polyurethane-based binders, polyurea-based binders, polycarbonate-based binders, polyether-based binders, polysulfone-based binders, polysulfide-based binders, polysiloxane-based binders, polyamide-based binders, chlorinated olefin-based binders, melamine-formaldehyde-based binders or urea-formaldehyde-based binders, polyester-based binders, acrylic-based binders or epoxy-based binders, or mixtures or copolymers thereof. In a preferred embodiment, the binder is a polyvinyl ester-based binder such as a vinyl acetate-based binder, an acrylate-based binder such as a styrene-acrylate copolymer, or an epoxy-based binder. In some cases, the intumescent or non-intumescent coating composition comprises one or more binders.

[0109] In some cases, the non-intumescent coating layer B comprises the same adhesive, or at least the same type of adhesive, as the intumescent coating layer A and, optionally, the intumescent coating layer C. The same adhesive type means, for example, that both adhesives are epoxy-based, or both adhesives are polyvinyl ester-based, (meth)acrylate-based, or the like. The advantage of layers A, B, and, optionally, C, comprising the same adhesive type is improved adhesion and compatibility. When adhesive systems with different properties are used, adhesion may be weak.

[0110] Preferably, both the intumescent and non-intumescent coating compositions comprise a polyvinyl ester binder, a (meth)acrylic binder ((meth)acrylic-based binder) and / or an epoxy binder. Vinyl ester binders (vinyl ester-based binders) such as vinyl acetate binders and epoxy binders are particularly preferred.

[0111] The binder can be soluble in an organic solvent. For example, the liquid carrier of the intumescent or non-intumescent coating composition can be an organic solvent, including but not limited to ketones, esters, alcohols, aromatics, and hydrocarbons. More preferably, the binder can be soluble or dispersible in water. For example, the liquid carrier of the intumescent or non-intumescent coating composition can be water.

[0112] The binder may also be solvent-free and used in solvent-free intumescent or non-intumescent coating compositions.

[0113] In one embodiment, the binder may be present in the intumescent coating composition in a range of 10 to 70 wt%, such as 10 to 50 wt%, based on the total coating composition. In one embodiment, the binder may be present in the intumescent coating composition in a range of 10 to 50 dry weight% of the total coating composition. Therefore, it can be concluded that the binder may be present in the intumescent coating layer A in a range of 10 to 50 dry weight%.

[0114] In one embodiment, the binder may be present in the non-intumescent coating composition in a range of 5.0 to 80 wt%, such as 7.0 to 70 wt%, based on the total weight of the coating composition.

[0115] In one embodiment, the binder may be present in the non-intumescent coating composition in a range of 10 to 70 dry weight %, such as 10 to 60 dry weight %, of the coating composition. Accordingly, it follows that the binder may be present in the intumescent coating layer B in a range of 10 to 70 dry weight %, such as 10 to 60 dry weight %.

[0116] Polyvinyl ester adhesive

[0117] Any known polyvinyl ester-based binder can be used to prepare the intumescent or non-intumescent coating composition, with polyvinyl acetate-based binders being particularly preferred.

[0118] In one embodiment, the polyvinyl ester-based adhesive is a polyvinyl ester-based homopolymer, such as a polyvinyl acetate-based homopolymer.

[0119] In another embodiment, the polyvinyl ester-based adhesive is a copolymer derived from a vinyl ester monomer such as vinyl acetate with at least one of ethylene, vinyl chloride, a different vinyl ester (e.g., a vinyl ester of one or more long-chain branched carboxylic acids), di-n-butyl maleate, (meth)acrylic acid, and a (meth)acrylate ester.

[0120] Copolymers of vinyl acetate and ethylene are particularly preferred.

[0121] In another preferred embodiment, the polyvinyl ester-based adhesive is derived from a copolymer of vinyl acetate and vinyl versatate.

[0122] The polyvinyl ester-based adhesive may also be a terpolymer, such as a terpolymer derived from ethylene, vinyl acetate and (meth)acrylate.

[0123] Suitable polyvinyl ester adhesives are commercially available. The polyvinyl ester adhesive may be solvent-based or water-based. Preferably, the polyvinyl ester adhesive is water-based.

[0124] The polyvinyl ester adhesive is preferably dispersed in water. The polyvinyl ester adhesive is typically present in the dispersion in the form of particles or droplets having an average size of 4 to 1000 nm, preferably 25 to 400 nm, more preferably 50 to 350 nm, such as 100 to 300 nm.

[0125] The polyvinyl ester droplets or particles preferably comprise 10 to 80 wt% of the dispersion relative to the total weight of the entire dispersion. A typical wt% range may be 35 to 60 wt%, such as 40 to 60 wt%, relative to the total weight of the entire dispersion.

[0126] In addition to water, the polyvinyl ester dispersion may also contain a polar organic solvent such as acetone, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, dioxane (dioxane), ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dipropylene glycol monomethyl ether (Dowanol DPM), ethylene glycol monopropyl ether, and ethylene glycol monohexyl ether. One or more of these may be used.

[0127] The polyvinyl ester dispersion may be prepared by any suitable method known in the art.

[0128] The polyvinyl ester dispersions may also contain surfactants, defoamers, rheology modifiers, pH adjusters and biocides. These components are further described under additives.

[0129] If the intumescent coating composition and the non-intumescent coating composition of the present invention comprise an aqueous polyvinyl ester dispersion, the content of organic solvent is preferably low, such as less than 5.0 wt% solvent, especially less than 2.0 wt% organic solvent, more especially less than 1.0 wt% organic solvent, for example 0.5 wt% or less.

[0130] The VOC content of the intumescent and non-intumescent coating compositions comprising the aqueous polyvinyl ester binder is preferably less than 250 g / L, more preferably less than 100 g / L, and most preferably less than 50 g / L. In some embodiments, the VOC content may be 25 g / L or less, such as 10 g / L or less. In this aspect, the volatile organic compound includes benzyl alcohol.

[0131] (Meth)acrylic adhesive

[0132] Any known (meth)acrylic adhesive can be used to prepare the intumescent or non-intumescent coating composition.

[0133] Typically, (meth)acrylic adhesives of interest are those prepared using one or more monomers such as (meth)acrylic acid or (meth)acrylate esters. esters) such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-1-methylethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and hydroxyisobutyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isopropylideneglycerol (meth)acrylate, glycerolformal (meth)acrylate, cyclictrimethylolpropane formal (meth)acrylate acrylate, 2-(dimethylamino)ethyl (meth)acrylate, 3-(dimethylamino)propyl (meth)acrylate, 2-(diethylamino)ethyl (meth)acrylate, 2-(diisopropylamino)ethyl (meth)acrylate, 2-(tert-butylamino)ethyl (meth)acrylate, and (meth)acrylic acid.

[0134] The (meth)acrylic binder used in the intumescent or non-intumescent coating composition may be a binder based on a monomer containing two or more polymerizable ethylenically unsaturated bonds. Examples of monomers containing two or more polymerizable ethylenically unsaturated bonds include monomers such as 1,2-ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,3-glycerol di(meth)acrylate, methacrylic anhydride, zinc di(meth)acrylate, and trimethylolpropane tri(meth)acrylate.

[0135] (Meth)acrylic monomers containing polyether or polysiloxane groups may also be used.

[0136] The monomers listed above can be combined with other non-(meth)acrylic monomers to prepare the desired polymers, such as styrene and acrylonitrile.

[0137] In a preferred embodiment, the (meth)acrylic adhesive is a styrene-(meth)acrylate copolymer.

[0138] (Meth) acrylic adhesives can be physically drying adhesives. (Meth) acrylic adhesives can also be cured by free radical polymerization using azo or peroxide initiators, such as those described in WO 2021 / 180488 Al and WO 2005 / 000975 Al. A crosslinking agent such as a difunctional or trifunctional (meth) acrylate or triallyl cyanurate may be present.

[0139] The (meth)acrylic adhesive can be dissolved in an organic solvent or dispersed in water.

[0140] The aqueous (meth)acrylic adhesive dispersion may also contain surfactants, defoamers, rheology modifiers, pH adjusters and biocides. These components are further described under additives.

[0141] Epoxy adhesive system

[0142] Any known epoxy adhesive can be used to prepare intumescent or non-intumescent coating compositions. Epoxy adhesives are cured using at least one curing agent. Other components such as reactive diluents, accelerators, silanes, and hydrocarbon resins may also be part of the epoxy adhesive system.

[0143] When an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition is typically provided in a kit form, and a first composition comprising the epoxy adhesive is mixed with a second composition comprising a curing agent to form the intumescent or non-intumescent coating composition shortly before applying the intumescent or non-intumescent coating composition to a substrate. After application, the intumescent or non-intumescent coating composition is cured on the substrate to form an intumescent or non-intumescent coating layer.

[0144] If an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition may be waterborne, solventborne or solventless.

[0145] Intumescent or non-intumescent coating compositions comprising epoxy-based binders may have a high solids content and, thus, a low level of volatile organic compounds (VOCs). Intumescent or non-intumescent coating compositions comprising epoxy-based binders preferably have a solids content of at least 90 wt.%, such as at least 95 wt.%, more preferably at least 99 wt.%, and especially 100 wt.%.

[0146] Intumescent or non-intumescent coating compositions comprising epoxy-based binders may contain very low organic solvent content, such as less than 5.0 wt% solvent, particularly less than 2.0 wt% organic solvent, more particularly less than 1.0 wt% organic solvent, for example 0.5 wt% or less.

[0147] The VOC content of the intumescent or non-intumescent coating composition comprising an epoxy binder is preferably less than 250 g / L, more preferably less than 100 g / L, and most preferably less than 50 g / L. In some embodiments, the VOC content may be 25 g / L or less, such as 10 g / L or less. In this aspect, the volatile organic compound includes benzyl alcohol.

[0148] Epoxy adhesives

[0149] The epoxy adhesive preferably comprises one or more epoxy adhesives selected from aromatic or aliphatic epoxy adhesives. The aromatic or aliphatic epoxy adhesive preferably comprises more than one epoxy group per molecule. The epoxy groups may be located internally or terminally on the epoxy adhesive or on a cyclic structure incorporated into the epoxy adhesive. Preferably, the epoxy adhesive comprises at least two epoxy groups to form a crosslinked network.

[0150] It should be understood that the epoxy adhesives of the present invention also include adhesives having a traditional epoxy 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.

[0151] Suitable aliphatic epoxy adhesives include epoxy and modified epoxy adhesives selected from alicyclic epoxy resins (cycloaliphatic epoxy) such as hydrogenated bisphenol A, hydrogenated bisphenol A novolac and dicyclopentadiene adhesives, glycidyl ethers such as polyglycidyl ethers of polyols, epoxy functional acrylic resins or any combination thereof.

[0152] Suitable aromatic epoxy adhesives include epoxy and modified epoxy adhesives selected from bisphenol epoxy adhesives such as bisphenol A, bisphenol F and bisphenol S, resorcinol diglycidyl ether (RDGE), novolac epoxy adhesives such as phenolic novolac type binders (bisphenol A novolac, bisphenol S novolac) and cresol novolac type binders or any combination thereof. In a preferred embodiment, the epoxy adhesive is an aromatic epoxy adhesive. Preferably, the aromatic epoxy adhesive is derived from a combination of a compound containing at least one epoxide functionality and an aromatic co-reactant containing at least two hydroxyl groups.

[0153] The preferred epoxy adhesive is a bisphenol epoxy adhesive. The preferred epoxy adhesive is a bisphenol A and bisphenol F epoxy adhesive or a bisphenol A / F epoxy adhesive.

[0154] The epoxy adhesive may be a modified epoxy adhesive. Preferably, the epoxy adhesive is modified using fatty acid, polypropylene oxide and / or polyethylene oxide.

[0155] The solid content of the epoxy adhesive is preferably greater than 70 wt.%, preferably greater than 80 wt.%, preferably greater than 90, and most preferably greater than 99 wt.%. In a further preferred embodiment, the epoxy adhesive contains no solvent.

[0156] Examples of suitable commercially available epoxy-based adhesives are:

[0157] -Bisphenol A epoxy adhesives: Epikote 828 from Hexion, Araldite GY 250 from Huntsman Advanced Materials,

[0158] Bisphenol F epoxy adhesives: Epikote 862 from Hexion, YDF-170 from Kukdo, GY285 from Huntsman, DE 354 from Dow, BFE-170 from CCP, or KF8100 from Kolon.

[0159] - Mixtures of bisphenol A and bisphenol F: DER 352 from Dow Chemicals, Epikote 235 from Hexion.

[0160] The epoxy adhesive can be a liquid epoxy adhesive or a solid epoxy adhesive or a combination thereof. It should be understood that "liquid" and "solid" refer to the physical state of the epoxy adhesive at ambient temperature and pressure (25° C. and 1 atm). In a preferred embodiment, the epoxy adhesive is a liquid epoxy adhesive.

[0161] The liquid epoxy adhesive may have an epoxy equivalent weight (EEW) value of 140 to 1000. EEW values ​​of less than 500, such as 156 to 300, and especially 156 to 250, are particularly preferred.

[0162] The viscosity of the liquid epoxy adhesive is preferably 1000 to 20000 mPas, more preferably 1500 to 15000 mPas.

[0163] The solid epoxy adhesive may have an equivalent epoxy weight (EEW) of 300 to 1000. However, it is most preferred that the EEW of the solid epoxy adhesive is in the range of 350 to 750, such as 400 to 700, especially 500 to 670. It is most preferred to use a solid bisphenol A epoxy adhesive.

[0164] If both liquid and solid epoxy adhesives are present in the epoxy adhesive system, it is preferred that the liquid epoxy adhesive is in excess relative to the solid epoxy adhesive.

[0165] The epoxy binder is preferably present in an amount of 5.0 to 60 wt.% based on the dry weight of the intumescent coating composition, such as 5.0 to 40 wt.% based on the dry weight of the intumescent coating. More preferably, the epoxy binder is present in an amount of 10 to 30 wt.% based on the dry weight, especially 12 to 28 wt.% based on the dry weight, and most especially 16 to 25 wt.% based on the dry weight. If a blend of epoxy binders is used, these percentages refer to the total epoxy binder content, i.e., the wt.% of each type is added together.

[0166] In a preferred embodiment, the epoxy adhesive includes a bisphenol A adhesive, such as 4,4'-isopropylidenediphenol-epichlorohydrin resin, bisphenol F adhesive, and / or novolac adhesive. Bisphenol A epoxy adhesives are known to those skilled in the art and have the following general structure.

[0167]

[0168] In a preferred embodiment, the epoxy adhesive comprises one or more bisphenol F epoxy adhesives.

[0169] The bisphenol F epoxy-based adhesive may have an EEW value of 100 to 350. However, it is particularly preferred that the EEW is 300 or less, such as 100 to 300, especially 150 to 250. Preferably, the bisphenol F epoxy-based adhesive is a liquid.

[0170] The Mw of the bisphenol F resin may be greater than 170 g / mol. Preferred bisphenol F (4',4'-methylene bisphenol) epoxy adhesives are derived from a combination of bisphenol F and epichlorohydrin. Difunctional epoxy bisphenol F adhesives are particularly preferred.

[0171] Combinations of two or more bisphenol F adhesives may be used. The viscosity of the bisphenol F adhesive is preferably from 1,000 to 10,000 mPas, more preferably from 2,000 to 5,000 mPas.

[0172] curing agent

[0173] In embodiments where an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition comprises at least one curing agent. The curing agent can be any curing agent commonly known as a curing agent for epoxy-based adhesives. Ideally, it is amine-based. Most preferably, it is a polyamine containing at least two amino groups. Particularly preferably, the curing agent is based on benzylamine, i.e., the curing agent comprises a benzylamine motif:

[0174]

[0175] The benzylamine in the curing agent can be optionally substituted on the ring, the methylene linker or the N atom, but one active hydrogen must be retained.

[0176] Suitable substituents include C 1-4 Alkyl, OH, OC 1-4 -alkyl, halogen, cyano, amine and alkylamino groups (C 1-4 -N).

[0177] To achieve a crosslinked network, the curing agent must contain at least two "reactive" hydrogen atoms. "Reactive" hydrogen atoms are those that transfer from the nucleophile to the epoxide oxygen atom during the ring-opening reaction. Curing agents typically contain at least two curing-reactive functional groups. Therefore, the curing-reactive amine group cannot be a tertiary amine group.

[0178] 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 polymer curing agents. The curing agent may alternatively also comprise at least one amino-functional polysiloxane.

[0179] An example of a suitable polythiol curing agent is pentaerythrioltetramercapto propionate. An example of a suitable commercially available polythiol curing agent is MERCAPTOPROPIONATE from Gabriel performance materials. GPM800.

[0180] In a preferred embodiment, the intumescent or non-intumescent coating composition comprises an epoxy binder and at least one amine-functional curing agent. The curing agent typically contains at least two amine groups. The amine groups can be primary or secondary amine groups.

[0181] Suitable curing agents comprising 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., polyoxyalkylene diamines), alkyleneamines (e.g., alkylenediamines), aralkylamines, aromatic amines, Mannich bases (e.g., those commercially sold as "phenalkamines"), polyamines containing benzylamine structures, amino functional silicones or silanes, and including epoxy adducts and derivatives thereof.

[0182] In a preferred embodiment, the amine functional curing agent comprises a cyclic structure, which includes alicyclic amines and modified products of alicyclic amines, preferably polyamines. The term cyclic includes alicyclic, aromatic and heterocyclic polyamines.

[0183] In a preferred embodiment, the amine functional curing agent is a polyamine curing agent comprising one or more benzylamine moieties.

[0184] Such as

[0185] The benzylamine in the curing agent may be optionally substituted on the ring, the methylene linker or the N atom, but one active hydrogen must remain.

[0186] Suitable substituents include C 1-4 Alkyl, OH, OC 1-4 - alkyl, halogen, cyano, amine and alkylamine groups (C 1-4 -N).

[0187] In a preferred embodiment, the curing agent is a polyamine curing agent containing one or more benzylamine motifs. More specifically, the curing agent contains two or more repeating units, that is, the curing agent is polymeric or oligomeric. Preferably, the curing agent is a polyamine polymer containing a benzylamine motif on at least one end of the polyamine polymer chain. The polyamine polymer may contain a benzylamine motif at both ends of the polymer chain. Each repeating unit may also contain a benzylamine motif. The benzylamine group may be substituted or unsubstituted.

[0188] In a preferred embodiment, the curing agent comprises at least two benzylamine groups.

[0189] In a particularly preferred embodiment, the curing agent comprises a benzylated polyalkylene polyamine structure as described in WO2017 / 147138.

[0190] The benzylated polyalkylene polyamine structure can be further reacted with, for example, phenolic compounds and formaldehyde to generate Mannich bases or epoxy-functional compounds to prepare epoxy adducts.

[0191] In a preferred embodiment, the amine-functional curing agent comprises a fatty amine motif. It is particularly preferred that the fatty amine is a primary amine. It can be a fatty monoamine, such as a fatty monoprimary amine. In particular, the curing agent can comprise a mixture of fatty monoamines, such as a mixture of fatty monoprimary amines.

[0192] The term fatty amine is defined as any amine attached to an aliphatic carbon chain having 8 or more carbon atoms. Preferably, the fatty amine comprises a carbon chain of at least 10 carbon atoms, preferably at least 12 carbon atoms, for example 8 to 30 carbon atoms, especially C12-20, for example, one or more amine functional groups such as NH2 are attached to the aliphatic carbon chain having 8 or more carbon atoms. The carbon chain may contain one or more unsaturated double bonds. The carbon chain is preferably linear (i.e., unbranched).

[0193] Examples of suitable fatty amines are octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, pentadecylamine, oleylamine, didecylamine, dodecyl-1,3-diaminopropane, cocoalkylamine, tallowamine and soyamine.

[0194] Cocoalkylamine and tallowamine are particularly preferred.

[0195] In a preferred embodiment, the amine functional curing agent comprises coconut alkylamine (CAS No.: 61788-46-3).

[0196] It should be understood that fatty amines derived from natural sources such as cocoalkylamine, tallowamine, and soyamine may comprise mixtures of different fatty amines.

[0197] The fatty amine in the amine functional curing agent may be part of a polyalkylene polyamine structure and / or an amine adduct. Alternatively, the amine functional curing agent may comprise a mixture of fatty amine and polyalkylene polyamine and / or amine adduct.

[0198] In one embodiment, adducts of amine curing agents may also be used. Such adducts may be prepared by reacting an amine with a suitable reactive compound such as an epoxy adhesive, an epoxy functional reactive diluent, an acrylate, a maleate, a fumarate, a methacrylate, or an electrophilic vinyl compound such as acrylonitrile.

[0199] Examples of suitable commercially available amine functional curing agents are:

[0200] Ancamine 2609, Ancamine 2695, Ancamine 2738, Ancamine 260A, Ancamine 500, Ancamide 506, Ancamine 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 3456 from Evonik, Epikure 3140 from Hexion, GX-483 from Kukdo Chemical, AP5050 from Admark Polycoats, and from Mitsubishi Gas Chemical Company Inc.'s MXDA and Gaskamine 240, and Aradur 42BD and Aradur 943CH from Huntsman Advanced Materials.

[0201] In a particularly preferred embodiment, the curing agent is an aliphatic and / or cycloaliphatic polyamine, such as the Ancamine curing agents from Evonik.

[0202] In another preferred embodiment, the curing agent is an amine functional polyamide curing agent. In a further preferred embodiment, the amine functional polyamide curing agent comprises one or more benzylamine structures.

[0203] It will be appreciated that the curing agent may be provided neat or in a solvent, ideally the curing agent is solvent-free.

[0204] One or more curing agents may be used in combination. In a preferred option, two or more curing agents are used in combination.

[0205] A preferred combination of curing agents is a combination of a polyamine curing agent containing a benzylamine structure and a curing agent containing an amine-functional polyamide containing a benzylamine structure.

[0206] The curing agent should cure the epoxy-based adhesive at a temperature in the range of 0 to 50° C. Preferably, the epoxy-based adhesive system cures at ambient temperature.

[0207] It is common to quote the equivalent weight of a curing agent in terms of "active hydrogen equivalent weight." The amount of "active hydrogen equivalent weight" associated with one or more curing agents is the sum of the contributions from each of the one or more curing agents. The contribution to the active hydrogen equivalent weight from each of the one or more curing agents is defined as the grams of curing agent divided by the active hydrogen equivalent weight of the curing agent, where the active hydrogen equivalent weight of the curing agent is determined as the grams of curing agent equivalent to 1 mol of active hydrogen. For adducts with epoxy resins, the contributions of the reactants before adduction are used to determine the amount of "active hydrogen equivalent weight" in the complete epoxy adhesive system.

[0208] It is also common to quote the number of "epoxy equivalents" in epoxy adhesives. "Epoxy equivalents" is the sum of the contributions from each of the one or more epoxy adhesives and any other epoxy-containing components, such as silanes or reactive diluents. The contribution from each of the one or more epoxy adhesives to the epoxy equivalent weight is defined as the number of grams of epoxy adhesive divided by the epoxy equivalent weight of the epoxy adhesive, where the epoxy equivalent weight of the epoxy adhesive is determined as the number of grams of epoxy resin equivalent to 1 mol of epoxy groups. For adducts with epoxy adhesives, the contributions of the reactants before adduction are used to determine the number of "epoxy equivalents" in the epoxy adhesive system.

[0209] Preferably, the ratio between the hydrogen equivalent of the total amount of the curing agent and the total amount of the epoxy equivalent in the epoxy-based adhesive system of the present invention is in the range of 50:100 to 120:100.

[0210] Particularly preferred compositions have a ratio between the hydrogen equivalents of the curing agent and the epoxy equivalents of the epoxy resin in the range of 60:100 to 120:100, such as 80:100 to 120:100, for example 90:100 to 110:100.

[0211] It should be understood that the curing agent is shipped separately from the epoxy adhesive and is mixed with the epoxy adhesive only shortly before application. Of course, the mixing ratio of the composition comprising the epoxy adhesive and the curing agent is controlled by the relative amounts of epoxy groups and active hydrogens present. Ideally, the solid volume mixing ratio of the first composition to the second composition is 1:1 to 10:1, preferably 1:1 to 5:1, and most preferably 1:1. The curing agent composition and the epoxy adhesive composition are mixed shortly before application to the substrate.

[0212] In one embodiment, the curing agent may be present in the intumescent or non-intumescent coating composition in a range of 5 to 25 wt%, such as 10 to 22 wt%.

[0213] Although curing accelerators can be used, in a preferred embodiment, the curing agent is used without a separate accelerator to accelerate the crosslinking process. However, some known curing agents are combined with accelerators such as tertiary amine catalysts, and this is also within the scope of the present invention.

[0214] It will be appreciated that to form a coating layer in the multi-layer intumescent coating of the present invention, the coating composition used for the layer in question may undergo a curing reaction. Thus, the coating layer may be cured. Thus, coating layer A may comprise an intumescent coating composition, or coating layer A may be formed from an intumescent coating composition, for example, by curing.

[0215] Determining the exact chemical composition of such a cured layer is challenging, so it is simpler to define the coating layer with reference to the coating composition that cures to form the coating layer.

[0216] Thus, viewed alternatively, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B directly thereon, wherein:

[0217] (i) Coating layer A is formed from an optionally cured intumescent coating composition comprising:

[0218] a) adhesives;

[0219] b) acid generators; and

[0220] c) a swelling agent; and

[0221] (ii) Coating layer B is formed from an optionally cured non-intumescent coating composition comprising:

[0222] a) adhesive; and

[0223] b) Fiber.

[0224] It will also be understood that in the final intumescent coating system, any solvent / water that may be present in the coating composition will evaporate, leaving a dry coating layer. Thus, coating layers A to C can be considered dry coating layers.

[0225] Reactive diluent

[0226] In one embodiment where an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition further comprises a reactive diluent. The reactive diluent preferably comprises epoxy and / or (meth)acrylic functional groups. The reactive diluent forms part of the adhesive system and reacts with the other components of the adhesive system during the curing process.

[0227] In a preferred embodiment, the reactive diluent is an epoxy-functional reactive diluent. The epoxy-functional reactive diluent can be monofunctional, difunctional, or polyfunctional. Combinations of reactive diluents having different functionalities can also be used.

[0228] Examples of such reactive diluents include phenyl glycidyl ether, alkyl glycidyl ether (number of carbon atoms in the alkyl group: 1 to 16), 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 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), 1,4-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 ether (preferably C1-5 alkylphenyl glycidyl ether), such as methylphenyl glycidyl ether, ethylphenyl glycidyl ether, propylphenyl glycidyl ether and p-tert-butylphenyl glycidyl ether (p-TBPGE), the reaction product of epichlorohydrin and oil obtained from cashew nut shell.

[0229] In a preferred embodiment, the epoxy-functional reactive diluent is the reaction product of epichlorohydrin and oil obtained from cashew nut shells, such as, for example, Cardolite NC-513 from Cardolite.

[0230] In another particularly preferred embodiment, the epoxy-functional reactive diluent is an aliphatic or alicyclic epoxy-functional reactive diluent. The aliphatic epoxy-functional reactive diluent is preferably formed by the reaction of a compound containing at least one aliphatic epoxy functional group (aliphatic epoxy functional group, aliphatic epoxide functional group) 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 8 to 14 are also preferred. Aliphatic epoxy-functional reactive diluents can contribute to the flexibility of the coating film.

[0231] In a preferred embodiment, the epoxy-functional reactive diluent is an aliphatic epoxy-functional reactive diluent, such as 1,6-hexanediol diglycidyl ether.

[0232] In a preferred embodiment, the epoxy-functional reactive diluent is a cycloaliphatic epoxy-functional reactive diluent, such as cyclohexanedimethanol diglycidyl ether.

[0233] In another preferred embodiment, the epoxy-functional reactive diluent is based on a polyether such as the diglycidyl ether of polyethylene glycol or polypropylene glycol.

[0234] The epoxy functional reactive diluent may also be based on triglycerides, such as castor oil. In a preferred embodiment, the epoxy functional reactive diluent is the triglycidyl ether of castor oil.

[0235] The epoxy equivalent weight (EEW) of the epoxy functional reactive diluent is preferably from 50 to 500, more preferably from 100 to 400, and most preferably from 100 to 300.

[0236] Epoxy-functional reactive diluents are distinct from epoxy adhesives. Preferably, the reactive diluent has a low molecular weight, such as less than 500 g / mol. Preferably, the epoxy-functional reactive diluent has a viscosity of <100 cP, preferably <50 cP, and preferably <35 cP. Therefore, it is liquid at 23°C and atmospheric pressure.

[0237] In another preferred embodiment, the reactive diluent comprises (meth)acrylic acid functional groups.

[0238] The (meth)acrylic acid functional reactive diluent is preferably an aliphatic (meth)acrylate comprising at least two (meth)acrylate functional groups connected by an organic linker. Such polyesters may be diesters, triesters or tetraesters.

[0239] The molecular weight of (meth) acrylate functional reactive diluent is preferably less than 1000, such as less than 750, especially less than 500g / mol.Ideally, (meth) acrylic acid functional reactive diluent is (meth) acrylate of polyol such as diol or triol or saccharide polyol such as sugar alcohol.All OH groups in polyol not necessarily all carry (meth) acrylate group, but should preferably have at least two ester functional groups (functionality) in (meth) acrylate. Suitable polyols for functionalization comprise alkylene glycol (for example hexylene glycol, pentanediol), saccharide (for example monosaccharide or disaccharide) or polyol (especially sugar alcohol), such as erythritol, sorbitol, maltitol and mannitol.

[0240] Particularly interesting (meth)acrylic acid functional reactive diluents have the formula

[0241]

[0242] wherein R is H or Me;

[0243] n is 2-5; and

[0244] L represents a residue of a polyol, such as a residue of hexanediol or a residue of a sugar or sugar alcohol. Thus, at least two OH groups of the polyol carry an acrylate of the formula shown above.

[0245] L preferably contains only atoms of C, H and O. The molecular weight of L is preferably low, such as 1000 g / mol or less.

[0246] It is common to quote the number of "acrylate equivalents" in a (meth)acrylate-functional reactive diluent. "Acrylate equivalents" is the sum of the contributions from each of the one or more (meth)acrylate-functional reactive diluents. The contribution to the acrylate equivalents from each of the one or more (meth)acrylate-functional reactive diluents is defined as the grams of (meth)acrylate-functional reactive diluent divided by the acrylate equivalent weight of the (meth)acrylate-functional reactive diluent, where the acrylate equivalent weight of the (meth)acrylate-functional reactive diluent is determined as the grams of (meth)acrylate-functional reactive diluent equivalent to 1 mol of acrylate groups. For adducts with curing agents, the contributions of the reactants prior to adduction are used to determine the number of "acrylate equivalents" in the complete (meth)acrylate-functional reactive diluent system. When formulating, it is common to include the "acrylate equivalents" in the total "epoxy equivalent weight."

[0247] A particularly preferred (meth)acrylic reactive diluent is trimethylolpropane triacrylate.

[0248] The viscosity of the (meth)acrylic functional reactive diluent is preferably less than 300 mPas, more preferably less than 200 mPas, and most preferably less than 150 mPas.

[0249] Preferred (meth)acrylic functional reactive diluents have acrylate equivalent weight (AEW) values ​​of 50-200, more preferably 70-150, and most preferably 80-125.

[0250] Mixtures of (meth)acrylic functional reactive diluents may also be used.

[0251] The above-mentioned reactive diluents may be used alone or in combination of two or more diluents.

[0252] The reactive diluent is preferably present in an amount of 0.25 to 15 wt.% based on the dry weight of the coating composition, preferably 0.5 to 10 wt.% based on the dry weight of the coating composition, more preferably 0.5 to 7.0 wt.% based on the dry weight of the intumescent or non-intumescent coating composition, especially 1.0 to 6.0 wt.% based on the dry weight, and even more especially 1.0 to 5.0 wt.% based on the dry weight of the coating composition. If a blend of reactive diluents is used, these percentages refer to the total content of reactive diluents, i.e., the weight % of each type is added together.

[0253] It should be understood that because the reactive diluent may react with the curing agent, the reactive diluent should be kept separate from the curing agent in a kit for forming an intumescent or non-intumescent coating composition.

[0254] Silane

[0255] In one embodiment in which an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition further comprises at least one silane. The silane is part of the adhesive system and reacts with the other components of the adhesive system during the curing process. Preferably, the silane is a functional silane containing functional groups that can react with the adhesive system, such as amine, epoxy, acryl, methacryl, thiol, and isocyanate groups. The silanes used in the present invention generally have a relatively low Mw, such as less than 400 g / mol. Suitable silanes have the general formula (I) or (II):

[0256] (I)YR (4-z) SiX z

[0257] wherein z is an integer from 1 to 3,

[0258] (II)YR (3-y) R 1 SiX y

[0259] Where y is an integer from 1 to 2,

[0260] each R is a hydrocarbylene group having 1 to 12 C atoms, optionally containing an ether or amino linker,

[0261] R 1 is a hydrocarbon group having 1 to 12 C atoms;

[0262] Each X independently represents a halogen group or an alkoxy group.

[0263] Y is a functional group that is reactive with an epoxy adhesive and / or a curing agent and is bonded to R.

[0264] Therefore, from one perspective, the binder system for an intumescent or non-intumescent coating system comprises:

[0265] (i) at least one epoxy adhesive;

[0266] (ii) at least one silane of formula (I) or (II)

[0267] (I)YR (4-z) SiX z

[0268] wherein z is an integer from 1 to 3;

[0269] (II)YR (3-y) R 1 SiX y

[0270] wherein y is an integer from 1 to 2;

[0271] Each R is an alkylene group having 1 to 12 C atoms, optionally containing an ether or amino linker, R 1 is a hydrocarbon group having 1 to 12 C atoms;

[0272] Each X independently represents a halogen group or an alkoxy group.

[0273] Y is a functional group that is reactive with an epoxy adhesive and / or a curing agent and is bound to R; and

[0274] (iii) at least one curing agent.

[0275] Preferably, Y is an isocyanate, epoxy, amino, hydroxyl, carboxyl, thiol, acrylate or methacrylate group, more preferably an epoxy, amino, acrylate or methacrylate group, most preferably an epoxy or amino group. Particularly preferably, Y is an epoxy group. The Y group can be combined with any part of the chain R. It should be understood that when Y represents an epoxy group, then R will have at least two carbon atoms to allow the formation of an epoxide ring system.

[0276] In a particularly preferred embodiment, Y is an amino group or an epoxy group. The amino group is preferably NH2. Preferably, Y is an epoxy group.

[0277] If the Y group is an amino group that can react with epoxy-based adhesives, it is preferred that the silane and curing agent be provided separately from the epoxy-based adhesive. Generally speaking, in the kit of the present invention, the silane should not react with any component of the kit's components in which it is present.

[0278] Each X independently represents a halogen group or an alkoxy group. It is particularly preferred that X is an alkoxy group, such as a C1-6 alkoxy group, especially a methoxy group or an ethoxy group. It is also particularly preferred that two or three alkoxy groups are present. Therefore, z is ideally 2 or 3, especially 3.

[0279] The subscript y is preferably 2.

[0280] R 1 Preferred is a C1-4 alkyl group, such as methyl.

[0281] R is a hydrocarbon group having up to 12 carbon atoms. A hydrocarbon group refers to 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 or cyclohexyl ring. The term "optionally containing an ether or amino linker" means that the carbon chain may be interrupted by -O- or -NH- groups in the chain, for example to form silanes such as [3-(2,3-epoxypropoxy)propyl]trimethoxysilane:

[0282] H2COCHCH2OCH2CH2CH2Si(OCH3)3.

[0283] R is preferably an unsubstituted (obviously except for Y), unbranched alkyl chain having 2 to 8 C atoms.

[0284] Thus, the preferred silane formula has structure (III)

[0285] (III)Y'-R'( 4-z' )SiX' z

[0286] wherein z' is an integer from 2 to 3,

[0287] R' is an unsubstituted, unbranched alkyl chain having 2 to 8 C atoms, optionally containing an ether or amino linker,

[0288] Y' is an amino or epoxy functional group bonded to the R' group, and

[0289] X' represents an alkoxy group.

[0290] Examples of such silanes are represented by a number of products manufactured by Evonik Industries AG, Rheinfelden, and sold under the brand name Dynasylan(R)D, Silquest(R) silanes manufactured by Momentive, and GENIOSIL(R) silanes manufactured by Wacker.

[0291] Specific examples include methacryloxypropyltrimethoxysilane (Dynasylan MEMO, Silquest A-174NT), 3-mercaptopropyltri(methyl)ethoxysilane (Dynasylan MTMO or 3201; Silquest A-189), 3-glycidoxypropyltrimethoxysilane (Dynasylan GLYMO, Silquest A-187), 3-glycidoxypropyltriethoxysilane (Dynasylan GLYEO), tris(3-trimethoxysilylpropyl)isocyanurate (Silquest Y-11597), γ-mercaptopropyltrimethoxysilane (Silquest A-189), β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (Silquest A-186), γ-isocyanatopropyltrimethoxysilane (γ-isocyanatopropyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane) (Silquest A-Link 35, Genosil GF40), (methacryloyloxymethyl)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.

[0292] Other specific silanes of interest include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-(aminoethyl)-aminopropyltrimethoxysilane H2NCH2CH2NHCH2CH2CH2Si(OCH3)3, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, (H2NCH2CH2NHCH2CH2CH2SiCH3(OCH3)2), [3-(2,3-epoxypropyloxy)propyl]triethoxysilane (H2COCHCH2OCH2 CH2CH2Si(OCH2CH3)3, [3-(2,3-epoxypropyloxy)propyl]trimethoxysilane (H2COCHCH2OCH2CH2CH2 Si(OCH3)3), and epoxy-functional silane oligomers such as MP200 from Momentive.

[0293] The silane 3-glycidoxypropyltrimethoxysilane is particularly preferably used. Mixtures of silanes can also be used.

[0294] The amount of silane present in the intumescent or non-intumescent coating composition may be in an amount of 0.1 to 15 wt% by dry weight, preferably 0.25 to 15 wt% by dry weight, such as 0.5 to 10 wt% by dry weight, more preferably 0.5 to 7.0 wt% by dry weight, especially 1.0 to 6.0 wt% by dry weight, and even more especially 1.0 to 5.0 wt% by dry weight, based on the dry weight of the coating composition. In some embodiments, the silane is present in an amount of 1.5 to 4.5 wt% by dry weight of the intumescent coating composition. If a blend of silanes is used, these percentages refer to the total silane content, i.e., the weight percentages of each silane are added together.

[0295] It will be appreciated that if the silane contains functional groups that can react with the epoxy binder, the silane should be kept separate from the epoxy binder in the kit used to form the intumescent coating composition.

[0296] hydrocarbon resins

[0297] In one embodiment in which an epoxy-based adhesive is used, the intumescent or non-intumescent coating composition may further comprise a hydrocarbon resin. The term hydrocarbon resin is a term of art and refers to a group of hydrophobic resins that are typically petroleum-derived, although some resins may also be of natural origin. Preferred hydrocarbon resins of the present invention contain only C and H atoms, but some may also contain O atoms, for example, where the -O- content may range from 0 to 10.0 wt %, such as from 0 to 5.0 wt %, of the hydrocarbon resin.

[0298] Preferably, the hydrocarbon resin has a low water solubility, such as less than 5 g / L, more preferably 2 g / L, most preferably 1 g / L.

[0299] Generally speaking, all types of hydrocarbon resins can be used, such as solid or liquid pure aromatic and / or aliphatic C5 and C9 hydrocarbon resins, mixtures of C5 / C9 aliphatic / aromatic raw materials, and modified hydrocarbon resins having epoxy or hydroxyl groups. C5 resins are generally oligomers or polymers formed from aliphatic monomers having five carbon atoms. C9 resins are generally oligomers or polymers of aromatic monomers having nine carbon atoms. Preferably, the hydrocarbon resin has a molecular weight of less than 1000 g / mol, and most preferably less than 500 g / mol.

[0300] Ideally, the hydrocarbon resin is a petroleum resin. Petroleum resin is a polymer that may contain hydroxyl groups and is formed using as a main raw material a fraction produced as a by-product from petrochemicals and carbon raw materials in petroleum refining.

[0301] Examples of petroleum resins suitable for the present invention include: aromatic petroleum resins obtained by polymerizing a C9 fraction (e.g., a styrene derivative, such as α-methylstyrene, o-, m-, p-cresol, indene, methylindene, cumene, naphthalene, or vinyltoluene) obtained from a heavy oil produced as a by-product by naphtha cracking, aliphatic petroleum resins obtained by polymerizing a C5 fraction such as 1,3-pentadiene or isoprene, 2-methyl-2-butene, cyclopentadiene, dicyclopentadiene, or cyclopentene. Copolymer petroleum resins obtained by copolymerizing a C9 fraction and a C5 fraction can also be used in the present invention, aliphatic petroleum resins in which a portion of a conjugated diene of the C5 fraction, such as cyclopentadiene or 1,3-pentadiene, is cyclically polymerized, resins obtained by hydrogenating an aromatic petroleum resin, and alicyclic petroleum resins obtained by polymerizing dicyclopentadiene.

[0302] It is also possible to use mixtures of diaryl and triaryl compounds obtained from the reaction of C9 blends under catalytic conditions. In these petroleum resins, hydroxyl groups are introduced.

[0303] Among the above petroleum resins, hydroxyl-containing aromatic petroleum resins are particularly preferred, and phenolic hydrocarbon resins are particularly preferred.

[0304] Another possible hydrocarbon resin is a xylene resin synthesized from 1,3-dimethylbenzene and formaldehyde. Xylene resins modified with phenols such as difunctional phenols (e.g., phenol, p-tert-butylphenol, p-cumylphenol, o-p-dicumylphenol) can also be used.

[0305] Another option is a coumarone resin, which is a copolymer containing a coumarin constituent unit, an indene constituent unit, and / or a styrene constituent unit in its main chain.

[0306] Indene-coumarone resins may be modified with phenol at the terminal, and at least a portion of the aromatic rings in the coumarone resin may be hydrogenated. Such coumarone resins include liquid products having a number average molecular weight (Mn) of 200 to 300 and solid products having a number average molecular weight (Mn) of 600 to 800, and either one of these may be used alone, or two of these may be used in combination.

[0307] In a preferred embodiment, the hydrocarbon resin is a xylene formaldehyde resin such as EPODIL LV5 from Evonik, or a phenol-modified hydrocarbon resin such as Novares LC15 from Rutgers.

[0308] Preferably, the hydrocarbon resin is a liquid hydrocarbon resin.

[0309] Hydrocarbon resins are preferably non-reactive, meaning they do not react with the other components of the intumescent coating composition. Therefore, hydrocarbon resins preferably do not contain any epoxy groups. These resins can help reduce the viscosity of the binder system resin and lower the surface tension, thereby improving surface wettability. They also add hydrophobic properties to the composition, which generally results in improved water resistance. They can also increase the flexibility of the coating film. Those skilled in the art are familiar with the concept of hydrocarbon resins.

[0310] Most preferred are hydrocarbon resins having an "O atom" content of 0 to 8.0 wt%, such as 0 to 5.0 wt%, or xylene formaldehyde having an OH content of <3 wt%.

[0311] It is also possible to use hydrogenated hydrocarbon resins based on natural resins such as rosins, for example gum rosin, wood rosin and tall oil rosin. It is also possible to use esterified hydrocarbon resins based on rosin esters.

[0312] Cardanol-based hydrocarbon resins may also be employed.

[0313] Preferably, the hydrocarbon resin forms 0.1 to 15 wt % by dry weight of the coating composition, preferably 0.5 to 10 wt % by dry weight, for example 0.5-8.0 wt % by dry weight, especially 0.75 to 5.0 wt % by dry weight, most especially 1.0 to 4.0 wt % by dry weight.

[0314] It will be appreciated that, as the hydrocarbon resin is preferably non-reactive, it may form part of any of the components of a kit for forming an intumescent coating composition.

[0315] Hydrocarbon resins can also be used as carbon donors in intumescent coatings.

[0316] accelerator

[0317] In one embodiment where an epoxy adhesive is used, the intumescent or non-intumescent coating composition further comprises a curing accelerator. The curing accelerator can be any known curing accelerator used in epoxy coating systems, such as tertiary amines, (meth)acrylates, imidazoles, organic acids, phenols, and organic phosphines.

[0318] Examples of suitable tertiary amines are triethanolamine, dialkylaminoethanol, triethylenediamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diaza-bicyclo[5.4.0]undec-7-ene and 2,4,6-tris(dimethylaminomethyl)phenol. A particularly preferred accelerator is 2,4,6-tris(dimethylaminomethyl)phenol, such as Ancamine K54 from Evonik.

[0319] Examples of suitable imidazoles are 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole and 2-heptadecylimidazole.

[0320] Examples of suitable organic acids are benzoic acid derivatives, such as salicylic acid.

[0321] Examples of suitable organic phosphines are tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine and phenylphosphine.

[0322] Examples of suitable phenols are alkylphenols, such as nonylphenol.

[0323] Examples of suitable (meth)acrylates are the same as described above for the (meth)acrylate functional reactive diluents.

[0324] flame retardants

[0325] The intumescent or non-intumescent coating composition may also comprise at least one flame retardant, such as a phosphorus-containing flame retardant. Suitable flame retardants include phosphoric acid, phosphites, phosphonates, and phosphates.

[0326] Preference is given to using triaryl phosphates, especially triphenyl phosphate.Where a flame retardant is used, this must be distinct and therefore separate from any other components of the intumescent or non-intumescent coating composition.

[0327] Preferably, the flame retardant forms 0.5 to 10 wt% by dry weight of the intumescent or non-intumescent coating composition, preferably 1 to 10 wt% by dry weight, such as especially 1 to 8.0 wt% by dry weight.

[0328] fiber

[0329] The non-intumescent coating composition comprises fibers. In some embodiments, the intumescent coating composition also comprises fibers. In some embodiments, the intumescent coating composition does not comprise fibers.

[0330] In some embodiments, the fiber is an inorganic fiber or an organic fiber. Typical inorganic fibers include: carbide fibers, such as boron carbide fibers, silicon carbide fibers, niobium carbide fibers, etc.; nitride fibers, such as silicon nitride fibers; boron-containing fibers, such as boron fibers, boride fibers; silicon-containing fibers, such as silica fibers, alumina-boron silica fibers, E-glass (non-alkali aluminum borate) fibers, C-glass (non-alkali or low-alkali sodium calcium-aluminum borosilicate) fibers, A-glass (alkali-sodium calcium-silicate) fibers, S-glass fibers, inorganic glass fibers, quartz fibers, etc. Glass fibers may include E-glass fibers, C-glass fibers, A-glass fibers, S-glass fibers, etc.

[0331] Useful inorganic fibers also include ceramic fibers and basalt fibers. Kevlar (para-aramid fibers) may also be used.

[0332] Preferred organic fibers are carbon fibers.

[0333] Other suitable fibers include mineral fibers. Typically, mineral fibers contain aluminum oxide, calcium oxide, iron oxide, magnesium oxide, and / or silicon dioxide.

[0334] In a preferred embodiment, the fibers are mineral fibers.

[0335] Preferably, the fibres form at least 0.25 wt%, preferably at least 1.0 wt%, preferably at least 5.0 wt% of the non-intumescent coating composition.

[0336] In some embodiments, the fibers form 0.25 to 25 wt %, preferably 1.0 to 20 wt %, of the non-intumescent coating composition.

[0337] In some embodiments, the fibers form 0.5 to 40% by dry weight, preferably 2.0 to 30% by dry weight of the non-intumescent coating composition. Thus, the fibers may be present in the non-intumescent coating layer B in a range of 0.5 to 40% by dry weight, such as 2.0 to 30% by dry weight.

[0338] In some embodiments, the average length of the fibers is from 50 to 6000 μm, preferably from 100 to 3000 μm, and especially from 125 to 3000 μm.

[0339] In a preferred embodiment, fibers of different average lengths are used. Thus, a first fiber population of length X can be combined with a second fiber population of different length Y. Using fibers of different average lengths helps create the fiber network required to stabilize the char of the intumescent composition. The difference in average length between the fiber populations can be at least 200 μm. For example, a first fiber population of 200 μm can be combined with a second fiber population of 500 μm. A fiber population is a plurality of fibers having substantially the same length.

[0340] In a particularly preferred embodiment, three or more fiber populations of different average lengths are used.

[0341] It is preferred that substantially all of the fibers have an average length of from 50 to 3000 μm. Fibers having an average length of less than 50 μm are not long enough to provide the web effect targeted herein.

[0342] In some embodiments, the melting point of the fibers is above 800°C, preferably above 1000°C, and especially above 1200°C.

[0343] Carbon donor compounds

[0344] In some embodiments, the intumescent coating composition includes a carbon donor compound. The carbon donor compound may include an organic polyol (i.e., an organic polyol) and / or expandable graphite. For example, the carbon donor compound may include pentaerythritol, dipentaerythritol, tripentaerythritol, a polysaccharide (e.g., starch, cellulose, glycogen, etc.), a disaccharide sugar (e.g., sucrose, lactose, maltose, etc.), a monosaccharide sugar (e.g., glucose, fructose, galactose, etc.), glycerol, or expandable graphite, or any combination thereof. When present, the carbon donor is preferably pentaerythritol or dipentaerythritol.

[0345] The intumescent coating composition may comprise 0.0 to 20 wt% carbon donor compound, such as 3.0 to 20 wt%, preferably 5.0 to 16 wt%, especially 7.0 to 14 wt% carbon donor compound on a dry weight basis, based on the total weight of the intumescent coating composition.

[0346] The intumescent coating composition may comprise 0 to 30% by dry weight, such as 8.0 to 20% by dry weight, of the carbon donor compound. Thus, it follows that the intumescent layer A may comprise 0 to 30% by dry weight, such as 8.0 to 20% by dry weight, of the carbon donor compound.

[0347] Acid-generating compounds

[0348] The intumescent coating composition comprises an acid-generating compound. The acid-generating compound may comprise a source of phosphoric acid or sulfonic acid capable of generating phosphoric acid or sulfonic acid upon exposure to heat, particularly at temperatures above 200°C. Examples of such sources include sodium phosphate, potassium phosphate (e.g., potassium tripolyphosphate), ammonium phosphate (e.g., ammonium polyphosphate (APP), monoammonium phosphate, diammonium phosphate), sodium sulfate, potassium sulfate, ammonium sulfate, magnesium sulfate, or p-toluenesulfonic acid, or any combination thereof.

[0349] In some examples, the acid-generating compound comprises a phosphate ester of a polyol, or an ammonium phosphate (eg, APP), or an amine phosphate (eg, melamine phosphate), or any combination thereof.

[0350] A particularly useful acid-generating compound is ammonium polyphosphate, because APP generates phosphoric acid at a temperature generally lower than the decomposition temperature of the aforementioned carbon-donating compounds. APP thus generates phosphoric acid that is readily available for participation in the carbonization reaction.

[0351] APP compounds are polyphosphates with POP bonds and can be represented by the following formula:

[0352] [NH4PO3] n

[0353] wherein the average value of n is at least about 10. APP compounds particularly useful in the intumescent coating compositions of the present invention include those having values ​​of n >1000.

[0354] The acid-generating compound may also comprise boric acid or a source of boric acid capable of generating boric acid upon exposure to heat, particularly at temperatures greater than 200° C. The source of boric acid may comprise, for example, a borate salt such as ammonium pentaborate, zinc borate, sodium borate, lithium borate, aluminum borate, magnesium borate, a borosilicate compound, and any combination thereof.

[0355] The intumescent coating composition may comprise 10 to 50 wt%, preferably 12 to 40 wt%, more especially 15 to 30 wt% of the acid generator, based on the total weight of the intumescent coating composition.

[0356] The intumescent coating composition may comprise 11 to 60 dry weight %, preferably 15 to 40 dry weight %, more especially 20 to 40 dry weight % of the acid generator, based on the total dry weight of the intumescent coating composition.

[0357] Thus, it can be concluded that the intumescent coating layer A comprises 11 to 60 dry weight %, preferably 15 to 40 dry weight %, more especially 20 to 40 dry weight % of acid generator, based on the total dry weight of the intumescent coating composition.

[0358] expansion agent

[0359] Intumescent coating compositions comprise an expandable intumescent material (also known as a blowing agent or expansion agent). The blowing agent generates a non-flammable gas, typically nitrogen, when exposed to fire or heat. The generated gas expands the carbonized material derived from the carbon source, forming a foamy protective layer. Suitable examples of commercially available blowing agents include, but are not limited to, nitrogen-containing compounds such as glycine, melamine, melamine salts, melamine derivatives, urea, urea derivatives, dicyandiamide, guanidine, and isocyanurate derivatives, particularly melamine.

[0360] Melamine derivatives include, for example, melamine formaldehyde, methylolated melamine, hexamethoxymethyl melamine, melamine monophosphate, di-melamine phosphate, melamine diphosphate, melamine polyphosphate, melamine pyrophosphate, melamine cyanurate, melamine borate, melam (N2-(4,6-diamino-1,3,5-triazin-2-yl)-1,3,5-triazine-2,4,6-triamine), melem (2,5,8-triamino-1,3,4,6,7, 9,9b-heptaazaphenalene (2,5,8-triamino-1,3,4,6,7,9,9b-heptaazaphenalene) and melon (poly[8-amino-1,3,4,6,7,9,9b-heptaazaphenalene-2,5-diyl)imino)).

[0361] Urea derivatives include, for example, N-alkylureas such as methylurea; N,N′-dialkylureas such as dimethylurea; and N,N,N′-trialkylureas such as timethylurea; guanylurea; guanylurea phosphate; formamide semicarbazide; guanylurea phosphate; 1,3-diaminourea; biurea, and the like.

[0362] Isocyanurate derivatives of interest include tris(2-hydroxyethyl)isocyanurate (THEIC).

[0363] Boron-containing compounds useful as blowing agents in the present invention include, but are not limited to, boric acid and borates, such as ammonium pentaborate, zinc borate, sodium borate, lithium borate, aluminum borate, magnesium borate, and borosilicates.

[0364] The blowing agent may also comprise a monomeric or polymeric compound such as meso-lactide, polylactide, polysulfone, polycarbonate, polyester, 1,1-diactivated vinyl compound, or addition polymer of 1,1-diactivated vinyl compound, or any combination thereof.

[0365] Physical blowing agents, such as expandable graphite and / or gas-incorporated expandable microspheres, may also be used.

[0366] The intumescent coating composition may comprise 0.5 to 10 wt%, preferably 1.0 to 8.0 wt%, more preferably 1.0 to 5.0 wt% of the intumescent agent, based on the total weight of the intumescent coating composition.

[0367] The intumescent coating composition may comprise from 1.5 to 15 dry weight %, preferably from 2.0 to 12 dry weight %, more preferably from 2.0 to 10 dry weight % of the intumescent agent, based on the total dry weight of the intumescent coating composition.

[0368] Therefore, it can be concluded that the intumescent coating layer A may comprise 1.5 to 15 dry weight %, preferably 2.0 to 12 dry weight %, more preferably 2.0 to 10 dry weight % of intumescent agent, based on the total dry weight of the intumescent coating composition.

[0369] Pigments and fillers

[0370] Intumescent and non-intumescent coating compositions may contain, in addition to the fibers described above, other pigments and fillers.

[0371] Suitable fillers include titanium dioxide, zinc oxide, aluminum oxide, carbonates, borates, silicon dioxide, silicates, heavy metal oxides such as cerium oxide, lanthanum oxide and zirconium oxide, kaolin, wollastonite, diatomaceous earth, bentonite, polymeric and inorganic microspheres such as uncoated or coated hollow and solid glass beads, uncoated or coated hollow and solid ceramic beads, porous and dense beads of polymeric materials.

[0372] Flake-like fillers such as mica, glass flakes, and micronized iron oxide (MiO) may also be used. Preferred fillers are titanium dioxide, kaolin, and wollastonite.

[0373] The filler preferably constitutes from 5% to 40% by weight of the intumescent or non-intumescent coating composition.The filler preferably constitutes from 10% to 50% by dry weight of the intumescent or non-intumescent coating composition.

[0374] Examples of the color pigment include titanium white, red iron oxide, yellow iron oxide, black iron oxide, carbon black, and organic color pigments.

[0375] additive

[0376] The intumescent and non-intumescent coating compositions may also contain various other additives. Suitable additives depend on the binder used and whether the coating composition is solvent-borne, water-borne, or solvent-free.

[0377] Examples of additives that may be present in the intumescent and non-intumescent coating compositions of the present invention include rheology modifiers, surfactants, defoamers, pH adjusters, dispersants, biocides, wetting agents, coalescing agents, and preservatives.

[0378] Suitable rheology modifiers may be polyamide waxes, polyethylene waxes, polysaccharide rheology modifiers, associative rheology modifiers, clays, cellulosic rheology modifiers, fumed silica, or mixtures thereof.

[0379] Various surfactants can also be used. This is particularly relevant for waterborne coating compositions. Many different surfactants may be suitable. The surfactant can be nonionic, anionic, cationic, or amphoteric.

[0380] The coating composition of the present invention may include a defoaming agent. Defoaming agents are sometimes also referred to as foam control agents or defoamers. A variety of defoaming agents are commercially available and can be used in the coating composition of the present invention. Representative examples of suitable defoaming agents include organosiloxanes, polyethers, polyether-modified silicones, mineral oils, and combinations thereof.

[0381] If the coating composition of the present invention is water-borne, the coating composition may include a pH adjuster such as ammonia, 2-aminopropanol, sodium hydroxide (NaOH), sodium carbonate (Na2CO3), and sodium bicarbonate (NaHCO3).

[0382] Coalescence agent can be optionally included in aqueous paint compositions.If coating composition is water-based, then coalescence agent can be optionally included.In aqueous paint compositions, the wet product applied is inhomogeneous, will be uniformly opposite with solventborne compositions when applying.In order to form film, polymer binder droplet or particle must coalesce.Coalescence agent helps this process in aqueous phase.The example of suitable coalescence agent is ester alcohol, benzyl alcohol, propylene glycol monomethyl ether (PM), propylene glycol propyl ether (PnP), dipropylene glycol n-butyl ether (DPnB), propylene glycol phenyl ether (PPh), tripropylene glycol n-butyl ether (TPnB), ethylene glycol propyl ether (EP), ethylene glycol butyl ether (EB), diacetone alcohol (DAA) and dipropylene glycol methyl ether (DPM).

[0383] In order to improve or promote the dispersion of pigments, fillers and fibers, it may be necessary to incorporate a wetting / dispersing additive. Many dispersants are commercially available and can be used in the coating compositions of the present invention. Suitable dispersants include conventional anionic, cationic, nonionic and amphoteric dispersants and combinations thereof.

[0384] Further optional additives may be included to aid char formation, strengthen the char, and prevent char degradation. Such additives include solids such as zinc borate, zinc stannate, zinc hydroxystannate, glass flakes, glass spheres, polymer spheres, fibers (ceramic, mineral, glass / silica based), aluminum oxyhydroxide, boron phosphate, and fumed silica.

[0385] The coating composition may also include an anti-corrosion component. Such components may include metal oxides, metal carbonates, talc, feldspar, etc., as anti-corrosion materials. Specific anti-corrosion functional pigments include zinc phosphate, zinc oxide, zinc powder, aluminum flakes, and lead oxide. Auxiliary corrosion inhibitors, such as molybdates, phosphates, tungstates, or vanadates, ultrafine titanium dioxide, and / or zinc oxide, and / or fillers such as silicon dioxide, calcined clay, aluminum silicate, talc, barite, or mica, may also be included.

[0386] The total amount of the above various additive components depends on the application and cannot be determined arbitrarily, but they are usually contained in the intumescent or non-intumescent coating composition in a total amount of 0.1 to 65 wt%, such as 0.5 to 50 wt%, preferably 0.5 to 30 wt%.

[0387] The total amount of the various additive components in the intumescent or non-intumescent coating composition may range from 0.5 to 75 wt. % on a dry weight basis, such as from 2 to 60 dry weight %.

[0388] organic solvents

[0389] The coating compositions of the present invention preferably contain low amounts of organic solvents.

[0390] The nature of the organic solvent is not limited, and known solvents with a wide boiling point range can be used. Examples of such solvents include xylene, toluene, MIBK, methoxypropanol, MEK, butyl acetate, benzyl alcohol, octylphenol, resorcinol, n-butanol, isobutanol, and isopropyl alcohol. The above solvents can be used alone or in combination of two or more.

[0391] If the coating composition is aqueous, a polar organic solvent such as acetone, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, dioxane, ethylene glycol, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, dipropylene glycol monomethyl ether (Dowanol DPM), ethylene glycol monopropyl ether, and ethylene glycol monohexyl ether may be present. One or more of these solvents may be present.

[0392] primer layer

[0393] In some embodiments, the substrate has a primer layer therein, over which the intumescent coating layer A is applied. The primer layer is conventional and is typically formed from an epoxy resin, although other options are possible. The primer layer preferably comprises at least 20 wt % epoxy resin, preferably at least 25 wt % epoxy resin.

[0394] Examples of suitable primer layers are coatings based on epoxy resins, modified epoxy resins (such as modified with polyvinyl butyral), polyurethane, acrylic, vinyl and chlorinated rubber. Preferably, the primer layer is an epoxy primer or a zinc-rich epoxy primer.

[0395] In another embodiment, the primer layer is a polysiloxane sol primer, such as described in US2014 / 0106176. Polysilane sol can be a component formed by the condensation reaction of at least one silane, to form a highly branched polysilane sol containing multiple free silanol functional groups (functionality). Polysilane sol can be derived from at least one alkoxysilane precursor, which is hydrolyzed to form corresponding silanols. It should be understood that in many alkoxysilanes, there are multiple alkoxy groups (usually up to three such groups), and therefore there may be multiple hydrolysis products depending on the hydrolysis procedure. The product of complete hydrolysis and partial hydrolysis can be formed. This hydrolysis reaction causes the formation of alcohol.

[0396] The hydrolyzed silanes / partially hydrolyzed silanes can then condense together, as is well known, to form complex oligomers / polymers. Due to the presence of various monomers when the hydrolysis reaction occurs, complex polysilane sols are formed which cannot be easily characterized by a general formula.

[0397] The dry film thickness of the primer is ideally in the range of 15 to 500 μm.

[0398] Top coating

[0399] A topcoat may be applied over the intumescent coating system. The topcoat is typically present for aesthetic reasons, but also to help protect underlying layers from damage by weather and sunlight. The topcoat is obtained by applying the topcoat composition to the non-intumescent coating layer B or the optional intumescent coating layer C, which is optionally cured or partially cured prior to application of the topcoat composition.

[0400] The topcoat composition may be solvent-borne or water-borne.

[0401] For example, the topcoat is preferably non-intumescent, eg, it should be free of acid-generating compounds and / or intumescent agents.

[0402] The topcoat layer is preferably free of fibers.

[0403] Preferably, the topcoat composition has a volume solids content of at least 35%, such as at least 50%, for example 50% to 60% volume solids.

[0404] The top coating composition may include a (meth)acrylic adhesive, a polyurethane adhesive, an alkyd resin adhesive, a vinyl adhesive, or a silicone adhesive. (Meth)acrylic adhesives, silicone adhesives, and polyurethane adhesives are preferably used.

[0405] The topcoat composition may comprise at least 30% by dry weight of a binder polymer, such as at least 40% by dry weight of a binder.

[0406] The topcoat composition may also contain standard additives such as pigments and fillers, thickeners, dispersants, and biocides. Suitable pigments and fillers include titanium dioxide, zinc oxide, aluminum oxide, barium sulfate, carbonates, borates, silicon dioxide, silicates, heavy metal oxides such as cerium oxide, lanthanum oxide, and zirconium oxide, mica, diatomaceous earth, and bentonite. A preferred filler is barium sulfate.

[0407] The filler preferably constitutes from 1% to 25% by dry weight of the topcoat composition.

[0408] Preparation and application of intumescent and non-intumescent coating compositions

[0409] The intumescent and non-intumescent coating compositions may be prepared by any suitable technique commonly used in the art of paint production. Thus, the various ingredients may be mixed together using a high-speed disperser, ball mill, pearl mill, three-roll mill, in-line mixer, or the like.

[0410] Conveniently, the intumescent or non-intumescent coating composition can be supplied as a ready-to-use one-component coating composition or as a multi-part kit, particularly when an epoxy adhesive is used. In one embodiment, part (A) comprises an epoxy resin and part (B) comprises a curing agent. Non-reactive components such as hydrocarbon resins, additives such as fillers and pigments, fibers, and the intumescent component can be supplied in either part (A) or (B). One skilled in the art will be able to design an appropriate kit to supply the components for transport.

[0411] It will be appreciated that the relative amounts of the components within any part of the kit will be determined by the final wt% values ​​and relative mixing ratios in the intumescent coating composition.

[0412] The intumescent and non-intumescent coating compositions to be used herein can be applied directly from a one-component coating composition or, if supplied as a kit of parts, can be conveniently prepared by mixing the components. For example, the first composition (A) and the curing agent component (B) (the second composition) can be mixed by adding the curing agent to the first composition and stirring thoroughly until the mixture is homogeneous. The mixture is immediately ready for application, for example by spray application or manual application, but an induction time can also be given before application.

[0413] Intumescent and non-intumescent coating compositions can be applied to substrates, particularly steel structures, by spraying using well-known dedicated 2-component airless spray pumps, 1-component airless spray pumps, or manually using, for example, a trowel or brush. For specialized multi-component sprays, it may be necessary to preheat the product to a pressure of up to 60°C and, for example, 3 to 6 bar.

[0414] The coating composition forming the intumescent coating layer A and the non-intumescent coating layer B may be applied in multiple layers to increase the layer thickness.

[0415] It is known to apply multiple layers of intumescent and non-intumescent coating compositions, but conventionally, each layer is cured (dried) before further layers are applied. In the present invention, further layers can be applied over a wet (or uncured) base layer. This speeds up the application process.

[0416] Because coating layer B is a liquid, it can be sprayed on top of coating layer A without stopping the process. When non-intumescent layer B is applied to intumescent layer A, intumescent layer A may be wet or dry.

[0417] An advantage of the coating system described herein is that the non-intumescent coating layer B is easier to apply than using the mesh described previously.

[0418] Repairs to small areas are also easier with Paint Layer B. If a fabric mesh is used, the repair method is much more complicated because a larger area may need to be removed in order to join the fabric mesh.

[0419] In a particularly preferred embodiment, the intumescent coating composition A comprises:

[0420] (i) 10 to 50% by dry weight of at least one binder;

[0421] (ii) optionally a curing agent;

[0422] (iii) 15 to 40% by dry weight of an acid-generating compound; and

[0423] (iv) 2.0 to 12% by dry weight of a bulking agent.

[0424] In a particularly preferred embodiment, the present invention provides a non-intumescent coating composition B comprising:

[0425] (i) 10 to 60% by dry weight of at least one binder;

[0426] (ii) optionally a curing agent; and

[0427] (iii) 0.5 to 40% by dry weight of fibers.

[0428] In a particularly preferred embodiment, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B, wherein:

[0429] Coating layer A includes

[0430] (i) 10 to 50% by dry weight of at least one binder;

[0431] (ii) 15 to 40% by dry weight of an acid-generating compound; and

[0432] (iii) 2.0 to 12% by dry weight of a bulking agent.

[0433] Coating layer B contains

[0434] (i) 10 to 60% by dry weight of at least one binder; and

[0435] (ii) 0.5 to 40% by dry weight of fibers.

[0436] In a particularly preferred embodiment, the present invention provides a multi-layer intumescent coating system comprising an intumescent coating layer A, a non-intumescent coating layer B, and an intumescent coating layer C, wherein:

[0437] Coating layer A contains

[0438] (i) 10 to 50% by dry weight of at least one binder;

[0439] (ii) 15 to 40% by dry weight of an acid-generating compound; and

[0440] (iii) 2.0 to 12% by dry weight of a bulking agent.

[0441] Coating layer B contains

[0442] (i) 10 to 60% by dry weight of at least one binder; and

[0443] (ii) 0.5 to 40% by dry weight of fiber; and

[0444] Coating layer C contains

[0445] (i) 10 to 50% by dry weight of at least one binder;

[0446] (ii) 15 to 40% by dry weight of an acid-generating compound; and

[0447] (iii) 2.0 to 12% by dry weight of a bulking agent.

[0448] The invention will now be described with reference to the following non-limiting examples.

[0449] Example

[0450] Preparation procedure of non-intumescent composition

[0451] The components of the non-intumescent coating composition were mixed on a high-speed dissolver in the parts by weight indicated.

[0452] The non-intumescent coating composition 1 was produced by the following process. A millbase was prepared with water, additives, and fillers. The millbase was stirred at high speed. Next, the binder and fiber were added and dispersed at low speed until no lumps were observed.

[0453] For non-intumescent coating composition 2, the binder was added first, followed by any pigments and fillers, and mixed at high speed until no lumps were visible. The total amounts of each component in the mixed coating composition are listed in Tables 3 and 4 below.

[0454] Preparation of intumescent composition 3

[0455] The components of intumescent coating composition 3 were mixed in the indicated weight portions on a high-speed dissolver. The resin was added first and blended at a low speed. The intumescent pigment and filler were then added and mixed at a high speed until no lumps were visible. Components (A) and (B) were prepared separately.

[0456] The total amounts of the components in the coating composition after mixing components (A) and (B) are listed in Table 2 below.

[0457] Fire Test (TTF)

[0458] In Examples 1-3 and Comparative Examples 1 and 2, the coating systems were tested on circular hollow sections (0.5 m high, 219 mm diameter, 8 mm wall thickness) in accordance with BS 476-Part 20: 1987. In Example 4 and Comparative Examples 3-5, the coating systems were tested on H-columns (0.5 m high, 254 flange depth (flange width, flanged ept), 254 web debt and 73 kg / m) in accordance with BS 476-Part 20 Appendix D.

[0459] Adhesion test

[0460] The coating system was applied in three layers to sandblasted steel panels (Sa 2 1 Adhesion tests were performed using a three-layer coating system comprising intumescent coating 3 as a first layer, intumescent coating 4 or non-intumescent coating composition 2 as a second layer, and intumescent coating 3 as a third layer. The first layer was applied to a dry film thickness of 3 mm and cured at 25°C for 1 day, the second layer was applied to a dry film thickness of 0.3 mm and cured at 25°C for 2 days, and the third layer was applied to a dry film thickness of 3 mm and cured at 25°C for 2 days.

[0461] Sample preparation

[0462] An epoxy shop primer was applied to a circular hollow profile (0.5 m high, 219 mm diameter, 8 mm wall thickness) or an H-pillar (0.5 m high, 254 mm flange depth, 254 mm web thickness, and 73 kg / m) at a depth of 20-30 μm. Next, an intumescent layer was applied, followed by a non-intumescent layer. A second intumescent layer was further applied. In Examples 1-3 and Comparative Examples 1-2, all coating layers were applied by spray application. In Example 4 and Comparative Examples 3-5, the intumescent coating layer was applied by trowel, while the non-intumescent coating composition 2 was applied by spray application.

[0463] The following materials were used in the examples:

[0464] Intumescent coating 1: Commercially available water-based, vinyl acetate adhesive, 60 min fire protection.

[0465] Intumescent coating 2: Commercially available water-based, vinyl acetate-based adhesive, 120 min fire protection.

[0466] Intumescent coating 3: Solvent-free, epoxy adhesive, see Table 2.

[0467] Non-intumescent composition 1: See Table 3.

[0468] Non-intumescent composition 2: See Table 4.

[0469] Table 1: List of components

[0470]

[0471] EEW = Epoxide Equivalent Weight AHEW = Amine Hydrogen Equivalent Weight

[0472] Table 2: Epoxy intumescent coating composition 3 1

[0473] Example 1 (wt.%) Component A Adhesive 2 (epoxy adhesive) 20.93 Epoxy-functional silanes 4.20 Flame retardant / plasticizer 1 3.55 Ammonium polyphosphate 34.78 Melamine 10.18 Pigments and fillers (total) - including mineral fibers (2%) 8.74 Component B Curing agent 1 8.81 Curing agent 2 8.81 total 100

[0474] 1 Components A and B are prepared separately and mixed shortly before application.

[0475] Table 3: Non-intumescent coating composition 1

[0476]

[0477] Table 4: Non-intumescent coating composition 2 1

[0478] Components Non-intumescent coating composition 2 (wt.%) Component A Adhesive 2 (epoxy adhesive) 26.5 Epoxy-functional silanes 5.3 Plasticizer / flame retardant 1 8.8 Filler 1 5 Filler 2 10 Filler 3 10 Rheology Modifier 2 1 Fiber 1 8.2 Fiber 2 4.9 Fiber 3 4.9 Component B Curing agent 1 15.38

[0479] 1 Components A and B are prepared separately and mixed shortly before application.

[0480] Table 5: Test results

[0481]

[0482] Table 6: Test results

[0483]

[0484] Table 7: Test results

[0485] Example 5 Comparative Example 6 Paint A Intumescent coating 3 (3mm) Intumescent coating 3 (3mm) Paint B Non-intumescent coating 2 (0.3mm) Intumescent coating 2 (0.3mm) Paint C Intumescent coating 3 (3mm) Intumescent coating 3 (3mm) Pull-off value (MPa) 10.3 1.6 Pull-off, fracture type Cohesive fracture in the final coating Adhesion failure between coating B and coating C

[0486] Comparative Example 1 is directly comparable to Examples 1-3 because the same intumescent coating was used and the overall DFT of the coating systems were comparable.

[0487] Comparative Example 1 opened up and collapsed after 60 minutes.

[0488] Examples 1-3 show that the presence of the non-intumescent layer increases the time to failure used at both 500° C. and 520° C. Examples 2 and 3 show a 27% improvement in TTF at 500° C., and Example 1 shows a 52% improvement in TTF at 500° C.

[0489] The advantage of the present invention is that the char is firstly prevented from splitting and thus the failure due to char failure is significantly reduced.Examples 1-3 demonstrate that the efficiency of an intumescent coating can be improved by using a non-intumescent coating containing fibers.

[0490] The results in Table 5 also demonstrate that the thickness of the non-intumescent layer affects the fire performance of the coating composition. Surprisingly, Example 1, which has the lowest DFT and overall thickness of the non-intumescent layer, performs best in the fire test. This indicates that an optimal DFT exists for this layer.

[0491] Comparative Example 2 includes Intumescent Coating 2, which is designed to have a longer TTF than Intumescent Coating 1. Nonetheless, Examples 1-3 all have significantly improved TTFs relative to Intumescent Coating 2.

[0492] When compared to Comparative Example 2, the coating system in Example 1 had a 31.9% improvement in TTF at 500°C, while Examples 2 and 3 had a 10.1% improvement in TTF at 500°C.

[0493] Example 4 demonstrates that, for an epoxy-based intumescent coating system, the non-intumescent coating composition 2 prevents char cracking and provides a 32% performance improvement compared to a coating system without a non-intumescent coating layer (Comparative Example 3). Furthermore, Comparative Examples 4 and 5 demonstrate that the non-intumescent coating composition 2 of the present invention provides performance comparable to conventional mesh in an epoxy-based intumescent coating system.

[0494] The data in Table 7 compares two intumescent coating systems with comparable DFTs, but differing in the properties of their intermediate layers (i.e., Coating B). The results show that Example 5, comprising non-intumescent Coating B, exhibits stronger intercoat adhesion when compared to Comparative Example 6, which comprises a full intumescent coating layer. In the working example, greater force was required to remove Coating C from Coating B. Furthermore, Comparative Example 6 demonstrated intercoat adhesion failure-type fracture, which is highly undesirable.

[0495] The present invention increases the effectiveness of existing or new intumescent coating products without the need to optimize or redevelop the intumescent composition itself.

[0496] An additional advantage of the present invention is that, unlike conventional meshes, non-intumescent coatings can be used in low DFT systems without affecting aesthetics.

Claims

1. A multi-layer intumescent coating system comprising an intumescent coating layer A and a non-intumescent coating layer B located directly thereon, wherein: (i) Coating layer A comprises or is formed from an intumescent coating composition comprising: a) adhesive; and (ii) coating layer B comprises or is formed from a non-intumescent coating composition comprising: a) adhesive; and b) Fiber.

2. The multi-layer intumescent coating system according to claim 1 , comprising an intumescent coating layer A and a non-intumescent coating layer B located directly thereon, wherein: (i) Coating layer A comprises or is formed from an intumescent coating composition comprising: a) adhesives; b) acid generators; and c) a swelling agent; and (ii) coating layer B comprises or is formed from a non-intumescent coating composition comprising: a) adhesive; and b) Fiber.

3. The multi-layer intumescent coating system according to claim 1 , comprising a second intumescent coating layer C located directly on layer B.

4. The multi-layer intumescent coating system according to claim 3, wherein: The coating layer C has the same composition as that of the coating layer A.

5. The multi-layer intumescent coating system according to any one of the preceding claims, wherein Layers A and B, and optionally layer C, comprise a polyvinyl ester-based adhesive, an epoxy-based adhesive and / or a (meth)acrylate-based adhesive.

6. The multi-layer intumescent coating system according to any one of the preceding claims, wherein Layers A and B, and optionally layer C, comprise a vinyl ester-based adhesive, or a multilayer intumescent coating system according to any one of the preceding claims, wherein layers A and B, and optionally layer C, comprise an epoxy-based adhesive.

7. The multi-layer intumescent coating system according to any one of the preceding claims, wherein Layers A and B, and optionally layer C, comprise the same type of adhesive.

8. The multi-layer intumescent coating system according to any one of the preceding claims, wherein The non-intumescent coating composition comprises 0.5 to 40 dry weight %, such as 2.0 to 30 dry weight %, of fibers.

9. The multi-layer intumescent coating system according to any one of the preceding claims, wherein Layer B comprises mineral fibers, carbon fibers, glass fibers and / or basalt fibers.

10. The multi-layer intumescent coating system according to any one of the preceding claims, wherein The layer B comprises at least two different fiber populations having different average lengths.

11. The multi-layer intumescent coating system according to any one of the preceding claims, wherein The dry film thickness of the coating layer B is 50 to 1500 μm, preferably 50 to 500 μm.

12. The multi-layer intumescent coating system according to any one of the preceding claims, wherein Coating layer A comprises a carbon-donating compound.

13. The multi-layer intumescent coating system according to any one of the preceding claims, wherein The system does not comprise a mesh.

14. The multi-layer intumescent coating system according to any one of the preceding claims, wherein: Coating layer A contains (i) 10 to 50% by dry weight of at least one binder; (ii) 15 to 40% by dry weight of an acid-generating compound; and (iii) 2.0 to 12% by dry weight of a bulking agent; and (i) coating layer B comprises 10 to 60% by dry weight of at least one binder; and (ii) 0.5 to 40% by dry weight of fibers.

15. The multi-layer intumescent coating system according to any one of the preceding claims, wherein The coating layer A and / or the coating layer B is cured.

16. The multi-layer intumescent coating system according to claims 2 to 15, wherein The adhesive comprises a polyvinyl ester adhesive, an epoxy adhesive or a (meth)acrylate adhesive or a mixture thereof; wherein the acid generator comprises a source of phosphoric acid and / or boric acid and / or sulfonic acid; and The expansion agent comprises a nitrogen-containing compound, a boron-containing compound or a monomeric or polymeric compound, and / or a physical foaming agent, such as graphite.

17. A substrate coated with a multilayer intumescent coating system according to any one of the preceding claims.

18. The substrate according to claim 17, wherein The multi-layer intumescent coating system is applied to a primer layer on the substrate.

19. The substrate according to claim 17 or 18, wherein A topcoat is applied over the multi-layer intumescent coating system.

20. A method for applying a multilayer intumescent coating system according to claims 1 to 16 to a substrate, comprising applying an intumescent coating composition A to the substrate and optionally curing the composition to form a coating layer A; and applying a non-intumescent coating composition B directly onto the coating layer A, and optionally curing the composition to form the coating layer B.

21. Use of the intumescent coating system according to any one of claims 1 to 16 for protecting substrates from fire.

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