Flexible two-component epoxy coating and their uses

Abstract

The present invention relates to a flexible two-component epoxy coating formulation for application on concrete floors and walls, both new and existing, as well as on metallic substrates such as iron, steel, and alloys. It can also be utilized as a protective coating for industrial equipment and structures.

Description

[0001] FLEXIBLE TWO-COMPONENT EPOXY COATING AND THEIR USES

[0002] FIELD OF THE INVENTION

[0003]

[0001] The present invention falls within the field of Chemistry, specifically in the area of paints and coatings, and relates to a flexible two-component epoxy coating for application on floors, new or used concrete walls, and metallic substrates such as iron, steel, and alloys. It can also be used as a protective coating for equipment and industrial structures.

[0004] BACKGROUND OF THE INVENTION

[0005]

[0002] Currently, conventional epoxy coatings exhibit low mechanical fracture resistance and film damage, as well as lack of elongation properties exceeding 20%. These characteristics result in poor impact damage resistance, which facilitates the onset of corrosion, accelerating asset degradation and significantly reducing its service life. Technologies that offer high-thickness epoxy coatings in a single application, flexibility, and mechanical performance, especially those adapted to tolerate wet surfaces and with the possibility of direct application on hydroblasted substrates, are not yet available on the market.

[0006] PRIOR ART

[0007]

[0003] Document by DRAKE et al. , titled "ELASTOMER- MODIFIED EPOXY RESINS IN COATINGS APPLICATIONS," pertains to the use of elastomer-modified epoxy resins in coatings for structural adhesives, composites, civil engine e r ing / cons true t ion, electrical laminates / encapsulants , and corrosion resistance. It mentions two methods for achieving elastomeric properties in a two-component epoxy coating (CTBN and ATBN) . The study uses polyamide hardeners and mentions amines modified with nitrile compounds in the composition. The formulations are quite simple and generic, with no mention of very high thickness applications (>1000 microns) or hydroblasting treatment. The study is also dated (1983) . Therefore, despite some similarities, arguments based on differences in formulation, application process, and test results can be used to distinguish the present invention.

[0008]

[0004] Document US Patent 7, 691, 944 B2, titled "PRIMER COMPOSITION AND USES THEREOF," describes a primer for a thermoplastic and / or elastomeric substrate, including a film of an epoxy-modi f ied polymer selected from a group consisting of epoxy-modi f ied thermoplastic polymers, epoxymodified thermoplastic polymer composites, epoxy-modi f ied elastomeric polymers, epoxy-modi f ied elastomeric polymer composites, mixtures thereof, and any combinations thereof . The technology described in this document differs significantly from the present invention as it does not address properties such as anticorrosive resistance and application on wet surf aces— non-metallic substrates. Additionally, the application layer is much thinner compared to the product proposed in the present invention.

[0009]

[0005] Document US Patent 9, 006, 385 B2, titled "ELASTOMERIC EPOXY MATERIALS AND THE USE THEREOF, " relates to an epoxy material cured with amine that combines the processing, mechanical, and adhesion properties of polyurethane elastomers with the thermal and hydrolytic stability typically associated with epoxy materials. It appears that the product proposed in this document serves as an alternative to FBE . Curing occurs at elevated temperatures, whereas the product proposed in the present invention requires ambient curing due to its application on floors and walls. Furthermore, it does not mention application on wet surfaces or the use of isocyanate.

[0010]

[0006] Document US Patent 10,596, 791 B2, titled "COCURED GEL COATS, ELASTOMERIC COATINGS, STRUCTURAL LAYERS, AND IN-MOLD PROCESSES FOR THEIR USE," discusses gel coats co-cured with urethane and vinyl ester, epoxy, or unsaturated polyester, showing improved resistance and flexibility compared to conventional polyester gel coats. The document proposes a urethane elastomeric resin rather than an epoxy one, as in the present invention. Items (vinyl, unsaturated polyester) are not used in the proposed product. Epoxy is mentioned only as an alternative. The focus is on gel coats, with a brief mention of floor painting. It does not address application on hydroblasted or wet surfaces or anticorrosive resistance .

[0011] SUMMARY OF THE INVENTION

[0012]

[0007] The present invention aims to propose a flexible two-component epoxy coating for application on floors, new or used concrete walls, and metallic substrates such as iron, steel, and alloys. It can also serve as a protective coating for equipment and industrial structures. The proposed coating provides high anticorrosive, mechanical, and chemical resistance against oils, solvents, acids, and bases. Additionally, it features elastomeric properties with elongation exceeding 20%, making it suitable for direct application on hydroblasted substrates and tolerant of wet surfaces.

[0013] BRIEF DESCRIPTION OF THE FIGURES

[0008] Figure 1 illustrates an example of the application, showing part of the pipe containing the applied flexible coating, with a uniform surface and no defects in the film.

[0014]

[0009] Figure 2 shows the appearance of the flexible coating applied during drying tests .

[0015] DETAILED DESCRIPTION OF THE INVENTION

[0016]

[0010] The present invention deals with a flexible two-component epoxy coating formulation comprising a two- component mixture, A and B, with the option of adding fillers to component B. The preferred mixing ratio between components A and B is 1: 1 (by volume) ; however, other mixing ratios may be used depending on the formulation, applicable to both cases of component B with and without fillers.

[0017] [Oil] Component A has the following composition:

[0018] - 40 to 70% by weight of epoxy resin;

[0019] - 1 to 15% by weight of crosslinking agent;

[0020] - 0.5 to 3% by weight of adhesion promoter additive;

[0021] - 0.01 to 2% by weight of dispersant additive;

[0022] - 0.01 to 2% by weight of surface additive;

[0023] - 1 to 5% by weight of rheological additive;

[0024] - 10 to 50% by weight of fillers and pigments.

[0025]

[0012] Component B has the following composition:

[0026] - 100% of curing agent

[0027]

[0013] When fillers are added, component B has the following composition:

[0028] - 40 to 100% by weight of curing agent;

[0029] - 0 to 5% by weight of rheological additive;

[0030] - 0 to 5% by weight of dispersant additive;

[0031] - 0 to 50% by weight of fillers and pigments.

[0014] The raw materials that can be used for components A and B are listed as follows:

[0032] 1. Epoxy Resins

[0033]

[0015] The epoxy resins are, preferably product from epichlorohydrin and bisphenol-A in liquid form, exhibiting high chemical and thermal resistance, stability, and adhesion to various substrates, and capable of being cured by aliphatic polyamines, polyamides, amidoamines, and cycloaliphatic amines. Other resins include bisphenol-F epoxy, epoxy esters, and novolac epoxy resins, or a mixture thereof .

[0034] 2. Crosslinking Agent

[0035]

[0016] Aromatic or aliphatic isocyanates may be used, including but not limited to hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, meta- tetramethylxylene diisocyanate, polymethylene polyphenyl isocyanate, and phenylenediisocyanate, preferably, a blocked isocyanate that acts as a crosslinking agent and adhesion promoter for hydroxyl - functional resins and is compatible with standard amine hardeners.

[0036] 3. Adhesion Promoter Additive

[0037]

[0017] Functional or epoxy-linked silanes, acrylic, or amino silanes can be used. Preferably, epoxy- functional silanes and trimethoxysilanes, which promote adhesion in various resin systems through the epoxy ring that reacts with various organic functionalities.

[0038] 4. Dispersant Additive

[0039]

[0018] Polymer solutions, carboxylic acids, solutions of alkylammonium salts of polycarboxylic acids, acrylate solutions, polyamine amide salts, polyesters, etc. , can be used. Preferably, solutions of long chain unsaturated polyamine amide salts and acid polyesters, which may also act as wetting agents are used.

[0040] 5. Surface Additive

[0041]

[0019] Compounds based on waxes, silicones, polyacrylate, metal oxide nanoparticles, fluoropolymers, among others, can be used, preferably, polyacrylate-based products with leveling properties, reduction of surface tension, and deaeration and anti-foaming effects.

[0042] 6. Rheological Additive

[0043]

[0020] Organic and / or inorganic sources, including but not limited to, silica dispersions, fumed silica, organophilic clays, polyamides, cellulose ethers, functionalized acrylic polymers, modified urethane resins, and organoti tanates . Preferably, at least one rheological additive based on fumed silica can be used.

[0044] 7. Fillers and Pigments

[0045]

[0021] In component A, they can be of organic and / or inorganic source. In addition, they can include but not limited to metallic oxides such as aluminum, iron, titanium, zinc, barium, copper, and silicon, as well as salts like sulfates, carbonates, silicates, titanates, chromates, and phosphates, in addition of organic compounds from the azo group, phthalocyanine, and carbon black. Other inorganic pigments, such as zinc and metallic aluminum, or a mixture thereof, may also be used.

[0046]

[0022] Additionally, various anticorrosive fillers and pigments with good dispersibility can be used, particularly those based on synthetic amorphous silica modified with calcium ions, which offer excellent corrosion protection without heavy metals and are non-toxic.

[0047]

[0023] Concentrated pigment bases may also be used for color adjustment and / or customization.

[0048]

[0024] Component B may or may not contain fillers and pigments. When added, they have the same origin as those described for component A.

[0049] 8. Curing Agent

[0050]

[0025] Curing agents may be based on polyamines, polyamides, amidoamines, and amines, preferably aliphatic or cycloaliphatic polyamines with or without modification, or a mixture thereof, which facilitate the curing of liquid epoxy resins at ambient temperatures.

[0051]

[0026] Additionally, other raw materials may be added, for example:

[0052] - Additional additives with specific functions, such as flame retardants, antioxidants, leveling agents, matting agents, crosslinkers, anti-foam agents, surfactants, lubricants, etc.

[0053] Fillers and pigments for color assignment and coverage power. Color concentrates are also optional.

[0054] If necessary, additional raw materials to adjust properties like viscosity, and coating color and gloss.

[0055] Solvents and thinners compatible with the formulation may be added without altering the desired properties of the product.

[0056]

[0027] For the production of components A and B, the carried-out steps resemble a traditional liquid paint production process involving mixing and homogenizing the formulation ingredients, for example: - Component A

[0057] Homogenization

[0058]

[0028] In a stainless-steel container, the following liquid ingredients are added: epoxy resin (1) , crosslinking agent (2) , and additives (3) to (6) . The resin should be added first, while the order of addition for the others is less critical. Homogenization begins with a mechanical mixer at 100-500 rpm.

[0059] Dispersion

[0060]

[0029] Solid materials (7) are added, gradually increasing the rotation to 500-1000 rpm (to promote particle dispersion) . The order of addition is less critical but should be done in parts to avoid solid agglomeration and loss of dispersion degree (paint fineness) . Dispersion causes a temperature rise in the mixture, which should be controlled to a maximum of 60°C. The mixture is maintained in agitation until the desired degree of dispersion (fineness) is achieved. This process is known as direct dispersion. An additional grinding operation may be performed to further enhance the dispersion degree of the mixture .

[0061] - Component B

[0062]

[0030] Similar to the production of Component A. For Component B without fillers, only the homogenization step is necessary .

[0063] Example of Formulation

[0064] Component A

[0065] - Epoxy resin of bisphenol A: 50% by weight (Epoxy

[0066] Resin) - Solution of long chain unsaturated polyamine amides and acidic polyesters: 1.5% by weight (Dispersant Additive)

[0067] - Fumed silica: 0.5% by weight (Rheological Additive)

[0068] - Polyamide thixotrope : 4.5% by weight (Rheological Additive )

[0069] - Quartz: 8.65% by weight (Fillers and Pigments)

[0070] - Hydrated magnesium silicate: 9% by weight (Fillers and Pigments)

[0071] - Titanium dioxide: 8% by weight (Fillers and Pigments)

[0072] - Zinc phosphate: 9% by weight (Fillers and Pigments)

[0073] - Epoxy- functional silane: 0.8% by weight (Adhesion Promoter Additive)

[0074] - Polyacrylate: 0.05% by weight (Surface Additive) Toluene diisocyanate: 8% by weight (Crosslinking

[0075] Agent )

[0076] Component B without filler

[0077] - Aliphatic polyamine: 60% (Curing Agent)

[0078] - Cycloaliphatic polyamine: 40% (Curing Agent)

[0079] Finished Product Characteristics

[0080] I . Visual Aspect: absent of failures

[0081] II . Flexibility (visual / manual) : Great

[0082] III . Maximum Strength: Over 50 N (ASTM D412)

[0083] IV. Flexibility Test: Elongation greater than 20% (ASTM D412)

[0084] V. Adhesion Strength: At least 15 MPa in pull-off test (ISO 4624)

[0085] VI . Corrosion Resistance: At least 4320 hours of Scab (ISO 11474) and 4200 hours of cyclic ageing test (ISO 12944-9) without corrosion spots and blistering .

[0031] Upon application and curing, the coating forms a dry film in a single coat with a thickness exceeding 500 micrometers, and can reach up to 10,000 micrometers if required, as showed in Figures 1 and 2 . The coating provides high resistance to corrosion, mechanical stress, and chemical exposure including oils, solvents, acids, and bases. Additionally, it features elastomeric properties with an elongation exceeding 20%, making it suitable for direct application on water-jetted substrates and tolerant of damp surfaces. With high impermeability, it is applicable in systems exposed to water and sewage, such as reservoirs, pipelines, and tunnels. Its chemical composition allows application on wet surfaces.

[0086] Application Method

[0087]

[0032] The preferred mixing ratio is 1 A: I B (volume) . The application can be done in a single coat, with a layer ranging from 500 microns to 10, 000 microns, depending on the surface and desired spread. The preferred application method is through dual-component airless spray gun. Other methods: conventional spray gun, rollers, brushes, and other manual application methods. Drying occurs at ambient temperature, with no need for ovens.

[0088] Substrates and Surface Preparation

[0089]

[0033] The surface must be properly cleaned, removing dirt, oils, greases, chemical products, and other contaminants before application. The application can also be performed over primers, adhesion promoters, directly on hydroblasted substrates, new and used concrete floors and walls, and metallic substrates.

Claims

SET OF CLAIMS1. Flexible two-component epoxy coating formulation characterized by comprising a two-component mixture, A and B, wherein:- Component A has the following composition:- 40 to 70% by weight of epoxy resin;- 1 to 15% by weight of crosslinking agent;- 0.5 to 3% by weight of adhesion promoter additive;- 0.01 to 2% by weight of dispersant additive;- 0.01 to 2% by weight of surface additive;- 1 to 5% by weight of rheological additive;- 10 to 50% by weight of fillers and pigments.- Component B has the following composition:- 100% of curing agent; wherein the preferred mixing ratio between components A and B is 1: 1 (by volume) .

2. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the Component A preferably has the following composition:- Epoxy resin of bisphenol A: 50% by weight;- Solution of unsaturated polyamine amides and acidic polyesters: 1.5% by weight;- Fumed silica: 0.5% by weight;- Polyamide thixotrope : 4.5% by weight;- Quartz: 8.65% by weight;- Hydrated magnesium silicate: 9% by weight;- Titanium dioxide: 8% by weight;- Zinc phosphate: 9% by weight;- Epoxy- functional silane: 0.8% by weight;- Polyacrylate: 0.05% by weight and- Toluene diisocyanate: 8% by weight.

3. Flexible two-component epoxy coating formulation, according to claims 1 and 2, characterized in that the Component B without filler preferably has 60% of Aliphatic polyamine and 40% of Cycloaliphatic polyamine.

4. Flexible two-component epoxy coating formulation, according to claims 1 and 2, characterized in that when fillers are added, component B optionally has the following composition :- 40 to 100% by weight of curing agent;- 0 to 5% by weight of rheological additive;- 0 to 5% by weight of dispersant additive; and- 0 to 50% by weight of fillers and pigments.

5. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the epoxy resin are selected from the group consisting of products from epichlorohydrin and bisphenol-A in liquid form, capable of being cured by aliphatic polyamines, polyamides, amidoamines, and cycloaliphatic amines; bisphenol-F epoxy, epoxy esters, and novolac epoxy resins, or a mixture thereof, preferably, products from epichlorohydrin and bisphenol-A in liquid form.

6. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the crosslinking agent are selected from the group consisting of aromatic or aliphatic isocyanates, mainly hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, metatetramethylxylene diisocyanate, polymethylene polyphenyl isocyanate, and phenylenediisocyanate.

7. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the adhesion promoter additive are selected from the group consisting of functional or epoxy-linked silanes, acrylic, or amino silanes, preferably, epoxy- functional silanes and trimethoxysilanes .

8. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the dispersant additive are selected from the group consisting of polymer solutions, carboxylic acids, solutions of alkylammonium salts of polycarboxylic acids, acrylate solutions, polyamine amide salts, polyesters, preferably, solutions of long chain unsaturated polyamine amide salts and acid polyesters.

9. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the surface additive are selected from the group consisting of compounds based on waxes, silicones, polyacrylate, metal oxide nanoparticles, fluoropolymers, preferably, polyacrylate- based products with leveling properties, reduction of surface tension, and deaeration and anti-foaming effects.

10. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the rheological additive are selected from the group consisting of organic and / or inorganic sources, mainly, silica dispersions, fumed silica, organophilic clays, polyamides, cellulose ethers, functionalized acrylic polymers, modified urethane resins, and organoti tanates , preferably, fumed silica.

11. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the fillers and pigments are selected from the group consisting of organicand / or inorganic sources, mainly metallic oxides such as aluminum, iron, titanium, zinc, barium, copper, and silicon, as well as salts like sulfates, carbonates, silicates, titanates, chromates, and phosphates, in addition of organic compounds from the azo group, phthalocyanine, and carbon black; inorganic pigments, such as zinc and metallic aluminum, or a mixture thereof .

12. Flexible two-component epoxy coating formulation, according to claim 1, characterized in that the curing agent are selected from the group consisting of polyamines, polyamides, amidoamines, and amines, preferably aliphatic or cycloaliphatic polyamines with or without modification, or a mixture thereof.

13. Flexible two-component epoxy coating formulation, according to any of the claims 1 to 12, characterized in that the finished product has the following characteristics; (i) visual aspect absent of failures, (ii) great visual or manual flexibility, (iii) over 50N of maximum strength (ASTM D412) , (iv) Elongation greater than 20% (ASTM D412) , (v) at least 15 MPa in pull-off test (ISO 4624) and (vi) corrosion resistance of at least 4320 hours of Scab (ISO 11474) and 4200 hours of cyclic ageing test (ISO 12944-9) .

14. Use of the flexible two-component epoxy coating formulation, as defined in any one of claims 1 to 13, characterized by being for application on floors, new or used concrete walls, and metallic substrates such as iron, steel, and alloys.

15. Use, according to claim 14, characterized by further being as a protective coating for equipment and industrial structures.

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