Primer hybrid, composition of primer hybrid based on water, and method of preparation of primer hybrid

Description

25 Hybrid primer, water-based hybrid primer composition, and method for preparing the hybrid primer. Cross-referencing related deposit requests

[001] The present application refers to and claims priority to Application US Provisional Patent Serial No. 63 / 460,152, filed April 18, 2023, pending, the content of which is incorporated herein by reference in its entirety. Technical field

[002] The present invention relates to water-based epoxy-polyurethane hybrid primer compositions, methods for their production and methods of use thereof, specifically as a primer on substrates containing metallic surfaces. Background of the invention

[003] There is a growing demand for the development and use of water-based coatings for environmental reasons, especially due to the negative environmental impacts resulting from solvent-based coating solutions, and particularly the volatile organic compounds (VOCs) associated with them. Solvent-based primers are frequently used in vehicle refinishing, providing improved performance in areas such as anti-corrosion. However, the VOCs associated with solvent-based primers represent one of the critical issues driving interest in replacing them with water-based primers.

[004] Low VOCs and zero emissions are significant advantages of water-based coatings, providing motivation for the development of various water-based coating solutions. Much effort has been focused on replacing solvent-based primers with water-based primers. However, past efforts have resulted in poor performance, specifically in the area of ​​corrosion protection, thus restricting the use of water-based primers, especially for refinishing. Petition 870250094414, dated 10 / 15 / 2025, page 11 / 45 / 25 vehicles and for the coating of other metallic surfaces in particular.

[005] A primer is a paint or coating product that allows for much better adhesion of the finishing paint to a surface than if it were used alone. It is designed to adhere to surfaces and form an adhesion layer that is better prepared to receive the paint. Compared to paint, a primer is not typically intended for use as the outermost durable finish and can instead be manipulated to have improved filling and adhesion properties with the underlying material. Sometimes this can be achieved through chemistry, and other times by controlling the physical properties of the primer, such as its porosity, tackiness, and hygroscopicity. Summary of the invention

[006] Consequently, an objective of the present invention is to provide water-based hybrid primer compositions that have a combination of properties not otherwise attainable with a single polymer-based primer.

[007] An additional objective of the present invention is to provide water-based hybrid primer compositions that can be applied to substrates, specifically metallic substrates, without the need to use an etching primer.

[008] An additional objective of the present invention is to provide water-based hybrid primer compositions that can be applied to substrates, specifically metallic substrates, after the initial application of an etching primer, wherein the water-based hybrid primer composition provides comparable or improved adhesion, anti-corrosion and anti-hydrolysis properties, among other properties, compared to conventional solvent-based primers used with etching primers.

[009] Another objective of the present invention is to provide methods for the production of water-based hybrid primer compositions of Petition 870250094414, dated 10 / 15 / 2025, page 12 / 45 / 25 present invention, and methods for its use.

[0010] These and other objectives of the present invention, alone or in combination, have been achieved by the discovery of a hybrid primer comprising a cross-linked network of polymers formed from an epoxy resin, a polyurethane dispersion and an isocyanate-containing compound; methods for its production and for its application in substrate coating, particularly coating of metallic substrates. Brief description of the drawings

[0011] A fuller appreciation of the invention and many of the advantages that accompany it will be readily obtained as it is better understood by reference to the following detailed description when considered in relation to the accompanying drawings, in which: Figure 1 provides a schematic representation of the reaction used to prepare an exemplary embodiment of the water-based epoxy-polyurethane hybrid primer of the present invention.

[0012] Figure 2 provides a schematic illustration of the structure of certain embodiments of the water-based epoxy-polyurethane hybrid primer of the present invention.

[0013] Figure 3A provides a photographic representation of the anticorrosion performance after 20 days of salt spray testing between substrates coated with a conventional solvent-based polyurethane primer control [(a) and (b)] compared with a water-based epoxy-polyurethane hybrid primer of certain embodiments of the present invention [(c) and (d)].

[0014] Figure 3B provides a graphical representation of the anticorrosive performance from the photographs in Figure 3A, where the values ​​in the darker box are the control (a) and the values ​​in the lighter box are embodiments of the present invention (b). Petition 870250094414, dated 10 / 15 / 2025, p. 13 / 45 / 25

[0015] Figure 4A is a further photographic representation of the anticorrosion performance after 20 days of salt spray testing between substrates coated with a conventional solvent-based polyurethane primer control [(a) and (b)] compared with a water-based epoxy-polyurethane hybrid primer of certain embodiments of the present invention [(c), (d), (e), and (f)].

[0016] Figure 4B provides a graphical representation of the anticorrosion performance from the photographs in Figure 4A, comparing the control of conventional 2K solvent-based polyurethane primer (a), an epoxy-polyurethane hybrid primer of the present invention containing 30% epoxy (b) and an epoxy-polyurethane hybrid primer of the present invention containing 50% epoxy (c). Detailed description of the invention

[0017] The present invention relates to water-based epoxy-polyurethane hybrid primers, methods used to prepare the primers, and their use as coatings on substrates, particularly metallic substrates. The water-based epoxy-polyurethane hybrid primers of the invention can be used alone as a direct-to-substrate application primer (or in certain embodiments, direct-to-metal application or DTM), or in combination with a surface treatment on the substrate to be coated, such as an etching primer or other chemical surface treatment to make the substrate surface more capable of receiving and adhering to the water-based epoxy-polyurethane hybrid primer of the invention.

[0018] Within the context of the present invention, the term hybrid primer includes, but is not limited to, semi- and fully interpenetrating crosslinked networks of two types of polymer, blends of two different types of polymer that have been chemically bonded either directly or by a bonding agent, chemically bonded crosslinked networks of two types of polymer, a crosslinked network of one type of polymer chemically Petition 870250094414, dated 10 / 15 / 2025, p. 14 / 45 / 25 modified by a compound that can then form its own cross-linked network after binding to the original cross-linked network, and similar.

[0019] Within the context of the present invention, the term water-based shall mean that the polymeric components are in an aqueous medium and that the VOC is less than 250 g / L. In certain embodiments, water-based coatings provide one or more of the following advantages: • Low toxicity and flammability due to low VOC levels and low PAH emissions • Lower cost compared to solvent-based coatings and, in most cases, no additives, thinners, or hardeners are required • Less coating is required to cover the same surface area compared to using solvent-based coating solutions • Paint guns can be easily cleaned with water or water-based solutions and do not require paint thinner, acetone, or methyl acetate (more environmentally friendly and safer for the user) • In addition, the drying time of water-based primer is shorter than that of solvent-based primer, and the drying time for sanding is close to that of solvent-based primer • There are no special storage requirements for water-based primer based on safety considerations and for the disposal of residual water-based primer

[0020] The term includes and its variations do not have a limiting meaning when these terms appear in the description and claims.

[0021] The mention of a numerical range using extremes includes all numbers contained within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Petition 870250094414, dated 10 / 15 / 2025, page 15 / 45 / 25

[0022] To the extent that the terms including, includes, having, has, with, or variants thereof are used in the present application, such terms are intended to be inclusive in a manner similar to the term comprising. The singular forms a, an, and the include plural referents unless the context clearly indicates otherwise. Furthermore, the terms a, an, the, at least one, at least one, one or more, and one or more are used interchangeably. Thus, for example, a coating composition comprising an additive means that the coating composition may include one or more additives. The approximation language, as used in the present invention throughout the descriptive report and claims, can be applied to modify a quantitative representation that could permissibly vary without resulting in an alteration of the basic function to which it relates.Consequently, a value modified by a term such as approximately should not be limited to the specified precise value. In some cases, the approximation language may correspond to the precision of an instrument for measuring the value. Furthermore, unless specifically stated otherwise, the use of terms such as first, second, etc., does not denote an order or importance, but rather the terms first, second, etc., are used to distinguish one element from another.

[0023] As used in the present invention, the terms may and may be indicate a possibility of occurrence within a set of circumstances; the possession of a specified property, characteristic or function; and / or qualifying another verb by expressing one or more of an ability, capacity or possibility associated with the qualified verb. Consequently, the use of may and may be indicates that a modified term is apparently appropriate, capable or suitable for an indicated capacity, function or use, although it should be considered that in some circumstances the modified term may Petition 870250094414, dated 10 / 15 / 2025, p. 16 / 45 / 25 sometimes not be appropriate, capable or suitable. For example, in some circumstances, an event or capacity may be expected, while in other circumstances the event or capacity may not occur - this distinction is encompassed by the terms may (m) and may (m) be.

[0024] In the descriptive report and claims, reference will be made to various terms that have the following meanings. The singular forms a, an, and the include plural referents unless the context clearly indicates otherwise. Approximation language, as used in the present invention throughout the descriptive report and claims, can be applied to modify a quantitative representation that could permissively vary without resulting in an alteration of the basic function to which it relates. Consequently, a value modified by a term such as approximately should not be limited to the specified precise value. In some cases, the approximation language may correspond to the precision of an instrument for measuring value. Furthermore, unless specifically stated otherwise, the use of the terms first, second, etc., does not denote an order or importance, but rather the terms first, second, etc.These are used to distinguish one element from another.

[0025] The term aqueous composition or dispersion in the present invention means that the particles are dispersed in an aqueous medium. An aqueous medium in the present invention has a continuous water phase that forms at least 50 percent by weight of the aqueous medium, the remaining composition of the aqueous medium comprising water-miscible particles and compound(s) such as, for example, alcohols, glycols, glycol ethers, glycol esters, and the like.

[0026] The term dispersion in the context of the present invention refers to a mixture of a dispersible polymer and a carrier. The term dispersion includes, but is not limited to, the term solution. Petition 870250094414, dated 10 / 15 / 2025, page 17 / 45 / 25

[0027] The terms preferred and preferred refer to embodiments of the invention that may produce certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, mention of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

[0028] As used in the present invention, the term structural units, also known as polymerized units of the named monomer, refers to the remnant of the monomer after polymerization or to the monomer in polymerized form.

[0029] All methods described in this invention can be carried out in any appropriate order, unless otherwise indicated in this invention or unless clearly indicated otherwise by the context. The use of any examples, or language describing an example (e.g., how) provided in the present invention, is intended to clarify the invention and not to impose a limitation on the scope of the invention. Any statement in this invention about the nature or benefits of the invention or preferred embodiments shall not be limiting. This invention includes all modifications and equivalents of the subject matter described in this invention as permitted by applicable law. Furthermore, any combination of the elements described above in all possible variations thereof is encompassed by the invention, unless otherwise indicated in this invention or unless clearly indicated otherwise by the context.The description of any reference or patent in the present invention, even if identified as prior, is not intended to constitute a grant that such reference or patent is available as prior art in relation to the present invention. No unclaimed language should be considered limiting the scope of the invention. Petition 870250094414, dated 10 / 15 / 2025, p. 18 / 45 / 25 Any statements or suggestions in this invention that certain features constitute a component of the claimed invention shall not be limiting unless mentioned in the appended claims. Neither the marking of the patent number on any product, nor the identification of the patent number with respect to any service, shall be deemed a representation that all embodiments described in the present invention are incorporated in said product or service.

[0030] Epoxy resins are well known as high-performance materials in various metal construction and coating applications, providing the combined properties of chemical resistance, adhesion, corrosion resistance, mechanical strength, and high flexibility in some cases. On the other hand, polyurethanes have demonstrated rapid reaction with isocyanate in a short period of time and improved coating performance properties such as a wide range of properties including hardness, abrasion and impact resistance, flexibility, and strong bonding. Water-based primers, both epoxy and polyurethane, are commercially available for use in the automotive refinishing area. However, individual epoxy water-based primers have some weaknesses, as a long drying time is undesirable in a fast coating process, and the sanding ability of epoxy primer is not as good as that of a polyurethane primer.The sandability of rigid epoxy resin is a disadvantage, as it is difficult to obtain a smooth surface with a higher optical appearance, especially when cured at room temperature. Longer drying times due to the slow reaction rate between the epoxy and an amine curing agent is another significant disadvantage, as most consumers seek a fast-drying process.

[0031] Polyurethane (PU) dispersions are PU resins dispersed in water, which can produce a unique combination of robustness, Petition 870250094414, dated 10 / 15 / 2025, page 19 / 45 / 25 mechanical properties and durability typically unattainable in other polymer chemistries. These resins are used on a wide range of surfaces and applications, including wood, metal, plastics, masonry, and textiles. Meanwhile, water-based polyurethane dispersions for adhesive manufacturing have excellent heat resistance, fast drying, bond fatigue resistance, and atomization performance. Although water-based polyurethanes demonstrate many advantages in terms of properties, the pore structure within the coating layer generated by the reaction of isocyanate with water can decrease the stability of the coating formed from polyurethanes.Additionally, the adhesive strength of polyurethane primers to steel is low, thus requiring the use of an etching primer first on the substrate, adding a step to the coating process and resulting in increased process and raw material costs.

[0032] Consequently, a primer is needed that can combine the chemical resistance, adhesion, corrosion resistance, mechanical strength and high flexibility of epoxy primers with the short drying time, hardness, abrasion and impact resistance and bonding properties of polyurethane primers.

[0033] Thus, one embodiment of the present invention provides a water-based epoxy-polyurethane hybrid primer that provides this desired combination of properties. The water-based epoxy-polyurethane hybrid primer of the embodiments of the present invention is obtained by mixing an epoxy resin and a water-based polyurethane dispersion together with an isocyanate compound. The reactions between the polyurethane and isocyanate dispersion, and the epoxy resin and isocyanate, generate two cross-linked networks as shown in Figures 1 and 2, separately. These two cross-linked networks can be cross-linked to each other by the isocyanate as a curing agent, whereby the adhesive and mechanical strengths of the film can be drastically improved. Petition 870250094414, dated 10 / 15 / 2025, p. 20 / 45 11 / 25 improved. The water-based epoxy-polyurethane hybrid primer of the embodiments of the present invention provides one or more of the following advantages: • Shorter drying time due to the rapid dispersion reaction of polyurethane and isocyanate • Improved flexibility of the epoxy resin due to the flexible polyurethane • Greater chemical and thermal stability due to the epoxy resin • No etch primer is required (although it can be used if desired) • Improved sandability of the film developed by the epoxy primer • Better anti-corrosion performance of the film

[0034] Consequently, in certain embodiments of the present invention, a hybrid primer is provided comprising a crosslinked network of polymers formed from an epoxy resin, a polyurethane dispersion and an isocyanate-containing compound.

[0035] Epoxy resin includes, but is not limited to, epoxies formed from epichlorohydrin and one or more bisphenol compounds. The one or more bisphenol compounds may be any suitable bisphenol compound and may be selected based on the desired end properties of the epoxy resin portion of the hybrid primer.

[0036] In certain embodiments, the bisphenol compound includes, but is not limited to, one or more compounds selected from the following: Structural Formula Name CAS HO — / / ---- / OH Bisphenol A 80-05-7 O \__ / \ / / - - Bisphenol AP 1571-75-1 Petition 870250094414, dated 10 / 15 / 2025, p. 21 / 45 12 / 25 Structural formula Nome CAS χ Λ / \ ” o ” Ύ Bisphenol AF 1478-61-1 . s Í>L , . At ' / \ H3—< -----í, 7—OH 'CH·., Bisphenol B 77-40-7 _0 = HO íZ}· / OH \= / / 0 Bisphenol BP 1844-01-5 h.,c CH- ΗΊ—-----' —OH '----' CH--; ''---\ ÇH, Bisphenol C 79-97-0 CI^^CI ΓΎιΓχ Bisphenol C 2 14868-03-2 / CHv-\ ---ς ^Ol- Ί Η λ ' Bisphenol E 2081-08-5 H-3-—<- OH-( \-, \ / / --H -- Bisphenol F 620-92-8 CH, H,CH,C < ) CH·, CH, i ú ? ' 4 ; oi . \ / ΐ a — ch, '—' Bisphenol G 127-54-8 Ηυ·, . UH HC Cl·. IC wl· Bisphenol M 13595-25-0 HQ. .3⁄4. ,C'H Üú S' II 0 Bisphenol S 80-09-1 hc uh .;·. ..-s.. ,-s.. ,ch m? - - < - c^ Bisphenol P 2167-51-3 QQ x *2ΗΊ ho < ΐ· - y oh ' ' CH; V Bisphenol PH 24038-68-4 Petition 870250094414, of 15 / 10 / 2025, p. 22 / 45 13 / 25 Structural formula Nome CAS oh, ηχ··^ Bisphenol TMC 129188-99-4 HO-y-}, A Bisphenol Z 843-55-0 0 \ / 0 „,n; ,ν;λ ° rr o 0 HO ΌΗ Dinitrobisphenol A-H-C 53232 Br^ X .Br V Π HO' yy OH Gr Gr Tetrabromobisphenol A 79-94-7

[0037] Preferably, one or more bisphenol compounds are selected from the group consisting of bisphenol A, bisphenol B, bisphenol E, bisphenol F and bisphenol AF.

[0038] The curing (or crosslinking) of epoxy resin can be achieved by reacting an epoxy with itself (homopolymerization) or by forming a copolymer with curing agents or polyfunctional hardeners. This curing is what generates the substance's qualities such as strength, durability, versatility, and adhesion. Any desired molecule containing a reactive hydrogen can be used to react with the epoxide groups of the epoxy resin. Common classes of hardeners for epoxy resins include amines, acids, acid anhydrides, phenols, alcohols, and thiols. These have a relative reactivity (lowest first) approximately in the order: phenol < anhydride < aromatic amine < cycloaliphatic amine < aliphatic amine < thiol.

[0039] Although some epoxy resin / hardener combinations will cure at room temperature, some may require heat. The temperature is sometimes increased gradually to control the curing speed and prevent excessive heat buildup from the exothermic reaction.

[0040] Hardeners that exhibit only low reactivity or Petition 870250094414, dated 10 / 15 / 2025, page 23 / 45 / 25 limited at room temperature, but which react with epoxy resins at elevated temperatures, are called latent hardeners. When using latent hardeners, the epoxy resin and the hardener can be mixed and stored for some time before use, which is advantageous for many industrial processes.

[0041] The epoxy curing reaction can also be accelerated by adding small amounts of accelerators. Tertiary amines, carboxylic acids, and alcohols (especially phenols) are effective accelerators.

[0042] The polyurethane dispersion of these hybrid primer embodiments is a water-based dispersion (or aqueous dispersion) of a polyurethane, preferably formed from one of an aliphatic diisocyanate or aromatic diisocyanate, one or more diols or polyols, a catalyst, and optionally, one or more additives selected from the group consisting of conventional chain extenders and crosslinkers in polyurethane chemistry.

[0043] In certain embodiments, the polyurethane dispersion comprises one or more hydroxyl and / or carboxyl functional groups that are reactive with one or both of the isocyanate-containing compound and the epoxy resin, in order to allow the formation of the crosslinked network of the hybrid primer in these embodiments.

[0044] The isocyanate-containing compound used in these embodiments may be any isocyanate compound reactive with any one of, and preferably with both, epoxy resin and polyurethane dispersion, and may preferably be a diisocyanate or polyisocyanate compound. Examples of such isocyanate-containing compounds include, but are not limited to, aliphatic isocyanate-containing compounds and aromatic isocyanate-containing compounds, which may be blocked or unblocked isocyanates, specific examples of which include, but are not limited to, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-diisocyanate Petition 870250094414, dated 10 / 15 / 2025, page 24 / 45 / 25 of dicyclohexylmethane (HMDI), and tetramethylxylylene diisocyanate (TMXDI), and blocked derivatives thereof.

[0045] If desired, any suitable isocyanate blocking agent may be used, including, but not limited to, sodium bisulfite, diethyl malonate, 3,5-dimethylpyrazole, methyl ethyl ketone oxime (MEKO), phenol, or caprolactam.

[0046] These same isocyanate-containing compounds, particularly diisocyanate and polyisocyanate compounds, can also be the isocyanate used in the preparation of polyurethane from polyurethane dispersion.

[0047] Figures 3A and 3B show the anticorrosive performance of water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention without the use of an etch primer compared to a conventional 2K solvent-based polyurethane control primer. The water-based epoxy-polyurethane hybrid primer of the embodiments of the present invention was sprayed onto a cold-rolled steel substrate without the use of an etch primer, and the conventional 2K solvent-based polyurethane control primer was sprayed onto a cold-rolled steel substrate previously treated with an etch primer. A base coat followed by a topcoat was then applied to each of these.

[0048] Prior to testing in the salt spray chamber, the properties of the control primers and the present invention on the cold-rolled steel substrates were measured, along with measuring the properties of each having the complete set of layers (including the base coat and the finishing resin). The results are shown in Table 1 below: Petition 870250094414, dated 10 / 15 / 2025, page 25 / 45 / 25 Table 1 ID Control Hybrid primer of the present invention Chemical composition of solvent-based PU primer 2K Hybrid epoxy-polyurethane Primer on cold-rolled steel substrate Grid 5B 5B Friction with MEK (cycle) >300 >300 Complete panel assembly Coating layer Etchant / primer or hybrid primer / base coat / finishing resin (mil) Thickness, mil 0.24 / 6.36 / 0.4 / 3.52 0 / 3.76 / 0.4 / 3.52 Impact (direct / indirect), psi 150 / 160 160 / 160 Tapered mandrel bending Approved Approved Dry adhesive (grid) 4% base coat adhesive failure 2% hybrid primer cohesion failure Gloss (20 degrees) 89.3 88.7 DOI 96.5 86.6

[0049] Thus, the coated substrates were tested in a salt spray chamber (according to ASTM B117 standard) for 20 days and the damaged areas of delamination and corrosion were examined. The results demonstrated that both the delamination and corrosion of the 2K solvent-based polyurethane control primer (a) (with etch primer) and the water-based epoxy-polyurethane hybrid primer of the embodiments of the present invention (b) (but without etch primer) were very similar as shown in Figure 3B.

[0050] A comparison of the properties of substrates coated using the water-based epoxy-polyurethane hybrid primer of embodiments of the present invention without an etch primer compared with substrates coated using conventional 2K solvent-based polyurethane control primer with an etch primer were essentially the same, except that substrates coated with embodiments of the water-based epoxy-polyurethane hybrid primer without an etch primer demonstrated slightly less image distinction (DOI) (86,6) compared with substrates coated with solvent-based polyurethane control primer. Petition 870250094414, dated 10 / 15 / 2025, p. 26 / 45 / 25 conventional 2K solvent using etch primer (96.5). Due to the presence of hydroxyl groups in the epoxy resin of the hybrid primer of the embodiments of the present invention, the adhesive strength of the coating using the hybrid primer of the present invention is improved compared with conventional polyurethane.

[0051] The performance of water-based epoxy-polyurethane hybrid primers of the present invention was further evaluated by the humidity chamber test (GM14729). The results showed no significant difference in performance for the water-based epoxy-polyurethane hybrid primers of the present invention compared to conventional polyurethane.

[0052] The water-based epoxy-polyurethane hybrid primers of the present invention were further tested using an etch primer (a solvent-based epoxy resin) coated onto the cold-rolled steel substrate first, followed by coating with the water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention. Each of the panels was then coated with a base coat, followed by a finishing resin. Figures 4A and 4B show the anticorrosion results of substrates coated with water-based epoxypolyurethane hybrid primer (at 30% epoxy content ((b) in Figure 4B; (c) and (d) in Figure 4A) and 50% epoxy content ((c) in Figure 4B; (e) and (f) in Figure 4A) by weight) with etch primer and those coated with conventional 2K solvent-based polyurethane control primer ((a) in Figure 4B; (a) and (b) in Figure 4A) with etch primer, respectively.It is clear that the anti-corrosion property of the epoxy-polyurethane hybrid using an etch primer is superior to that of conventional solvent-based polyurethane control primers. The use of an etch primer significantly increases the adhesive strength of water-based epoxy-polyurethane hybrid primers of the present invention. Since the primers... Petition 870250094414, dated 10 / 15 / 2025, p. 27 / 45 / 25. While the hybrid primers of the present invention provide comparable adhesive properties without the use of an etch primer, the introduction of an epoxy-based etch primer increased the adhesive strength between the hybrid primer of the present invention and the cold-rolled steel substrate. Consequently, the anti-corrosion properties increased due to the strong adhesion of the hybrid primers of the present invention to the substrate.

[0053] The performance of substrates coated with the water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention compared to substrates coated with the conventional 2K solvent-based polyurethane control primer before and after the humidity chamber test was also tested. Low adhesive strength was observed in the substrates coated with the conventional polyurethane control primer after the humidity chamber test at room temperature for one hour or 24 hours, whereas improved adhesive strength was achieved by the substrates coated with the water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention, particularly when the amount of epoxy content was about 30% by weight in the water-based hybrid primer.Consequently, in embodiments of the water-based epoxy-polyurethane hybrid primer of the present invention, the epoxy content is preferably 20 to 40% by weight relative to the total amount of primer, more preferably 25 to 35% by weight relative to the total amount of primer.

[0054] The improvement in film durability was also evaluated by the gravel / stone impact test (GMW 14700). The water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention were found to provide improved durability compared to a conventional 2K solvent-based polyurethane primer. The improved durability can be attributed to the rigid structure of the epoxy resin.

[0055] A further comparison was made between the control of Petition 870250094414, dated 10 / 15 / 2025, p. 28 / 45 / 25 conventional 2K solvent-based polyurethane primer and water-based epoxy-polyurethane hybrid primers of the embodiments of the present invention, wherein the NCO / OH equivalent ratio increased to 1.5 and varying amounts of organic solvent (30%, 50%, and 100%) were included in the composition. No significant alteration in properties was found for the embodiments of the hybrid primers of the present invention, except that chemical resistance decreased at higher levels of organic solvent in the hybrid primers. Hybrid primers using the organic solvent were found to have higher gloss and DOI properties compared to panels having lower NCO / OH equivalent ratios.Without adhering to any particular theory or mechanism of action, it is believed that this improvement in brightness and DOI occurs due to the ability to create a denser cross-linking network, leading to the easier construction of a smooth surface.

[0056] Normally, coatings will degrade after exposure to a high humidity and temperature environment. The performance of coated panels in terms of anti-degradation using the hybrid primers of the present invention with higher equivalent weight ratios between NCO and OH was evaluated by exposure in a humidity chamber for 4 days. The optical appearance of the panels in relation to gloss 20 and DOI was similar to that of the conventional 2K polyurethane primer control. Some samples also demonstrated better gloss 20 and DOI after the humidity test. Again, without adhering to any particular theory or mechanism of action, it is believed that this can be attributed to a more stable structure generated by the hybrid primer of the present invention.

[0057] A measurement of adhesive loss of the coatings on the panels, measured before and after exposure in the humidity chamber, showed no significant difference in adhesive strength loss between the control primer and the hybrid primers of the present invention. Petition 870250094414, dated 10 / 15 / 2025, page 29 / 45 / 25

[0058] The anti-corrosion performance of the various panels (conventional 2K polyurethane control primer, hybrid primers of the present invention with varying levels of organic solvent from 0 to 100%) was subjected to a salt spray chamber test. No significant difference in the size of the corrosion was found between that of the control and that of the embodiments of the present invention that were tested. However, it was found that the amount of delamination of the panels using hybrid primers of the present invention increased with higher amounts of organic solvent present.

[0059] Measurements of various properties were carried out as follows: Chemical resistance of primer - To verify the chemical resistance of a primer, panels coated with etch primer and primer are rubbed with a hammer covered with three layers of fiber paper soaked with MEK solvent. The MEK test chemical resistance specification is greater than 300 cycles without the surface dissolving and the steel surface being exposed, according to ASTM D5402-19.

[0060] Adhesive strength - The adhesive strength of the coating / film is evaluated by grid test according to ASTM D3359. The failure mode of the coating / film is also evaluated based on observation of coating / film peeling off on tape and substrate. This test rates the adhesion strength of the coating / film in each layer by removing the pressure-sensitive tape attached to the film cut by the grid.

[0061] Impact resistance - The impact resistance of the coating / coated film on the panels is evaluated according to ASTM D5420. The data is repeated twice, and the coated and uncoated sides are tested and recorded as direct and indirect impact resistance. Petition 870250094414, dated 10 / 15 / 2025, p. 30 / 45 / 25

[0062] Tapered mandrel bending - The flexibility of the coating / film is evaluated by tapered mandrel bending according to ASTM D522.

[0063] Gravel / stone impact test - Film durability is measured according to GM 14729.

[0064] Optical Appearance - The optical appearance of the coating / film is evaluated by Gloss Retention (Gloss at 20 Degrees) and DOI Retention (Wavescan).

[0065] Humidity Chamber - Panels with edges are placed in a humidity chamber at a temperature of approximately 30°C for 4 days in accordance with GM 14729. The panels are dried with fiber paper after removal from the chamber and exposed at room temperature for 1 and 24 hours. The coating / film is then measured to determine gloss (20 degrees), DOI, and checkerboard pattern.

[0066] Salt spray chamber - Panels with painted edges and a scratched line down the middle are placed in a salt spray chamber at a temperature of approximately 30°C for 20 days according to ASTM B117. The panels are washed with hot water and any loose coating / film is removed with a metal spatula after removal from the chamber. The size of the delamination and corrosion area is measured and the average of ten measurement data points is calculated.

[0067] One embodiment for applying the hybrid primers of the present invention comprises spraying a solution of the water-based epoxy-polyurethane hybrid primer of the present invention onto a cold-rolled steel substrate, with or without the application of an etch primer. After overnight drying at room temperature (23 °C) and normal humidity (~50%), the resulting coatings are sanded using 400-grit and 600-grit sandpaper separately. Finally, an acrylate base coat and a finishing resin are sprayed onto the films. Petition 870250094414, dated 10 / 15 / 2025, p. 31 / 45 / 25 separately and dried at room temperature.

[0068] The water-based epoxy-polyurethane hybrid primer of some embodiments of the invention may be prepared by any desired method whereby the epoxy resin and the polyurethane dispersion become a cross-linked network, including, but not limited to: mixing the epoxy resin, the polyurethane dispersion and the isocyanate-containing compound in an aqueous medium at a temperature and for a time sufficient to cause a reaction between the epoxy resin, the polyurethane dispersion and the isocyanate-containing compound, to form the cross-linked network.

[0069] In a method of preparing the hybrid primers of the present invention, a water-based epoxy primer, optionally including one or more solvents, additives, pigments, or corrosion inhibitors, is prepared by combining the optional components and mixing until completely dispersed, such as by stirring with a dispersing disc for one hour, then the epoxy latex is added to the mixture, followed by cooling the resulting composition to room temperature. The polyurethane or latex dispersion is prepared by combining one or more optional solvents, additives, pigments, and corrosion inhibitors as desired, and the resulting composition is mixed, preferably by the dispersing disc. After mixing, the polyurethane dispersion is added, and the resulting mixture is stirred and cooled.

[0070] The water-based epoxy primer and the resulting polyurethane dispersion are combined with the isocyanate-containing compound, optionally with one or more pigments, solvents and additives, and the resulting composition is further stirred to allow the reaction between the epoxy, the polyurethane, and the isocyanate-containing compound to provide the cross-linked network of the hybrid primers of the embodiments of the present invention.

[0071] Although the embodiments discussed in the present invention have been related to water-based hybrid primers and methods Petition 870250094414, dated 10 / 15 / 2025, p. 32 / 45 / 25 discussed above, these embodiments are intended to be examples only and are not intended to limit the applicability of these embodiments only to the discussions presented in the present invention.

[0072] The above description is merely illustrative of various possible embodiments of various aspects of the present invention, and equivalent alterations and / or modifications will occur to others skilled in the art after reading and understanding this descriptive report and the accompanying drawings. Furthermore, although a specific feature of the invention may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations, as may be desired and advantageous for any given or specific application.

[0073] The following are non-limiting examples of some embodiments of the present invention: Possibility 1. A hybrid primer comprising a cross-linked network of polymers formed from an epoxy resin, a polyurethane dispersion, and an isocyanate-containing compound.

[0074] Embodiment 2. The hybrid primer of Embodiment 1, wherein the polyurethane dispersion comprises hydroxyl and carboxyl functional groups reactive with one or both of the isocyanate-containing compound and the epoxy resin.

[0075] Embodiment 3. The hybrid primer of one of Embodiments 1 or 2, wherein the polyurethane dispersion comprises a polyurethane formed from one of an aliphatic diisocyanate or an aromatic diisocyanate, one or more diols or polyols, a catalyst and, optionally, one or more additives selected from the group consisting of chain extenders and crosslinkers.

[0076] Modality 4. The hybrid primer of any of the Modalities 1 to 3, wherein the epoxy resin is formed by units of Petition 870250094414, dated 10 / 15 / 2025, p. 33 / 45 / 25 epichlorohydrin and one or more bisphenol compounds.

[0077] Modality 5. The hybrid primer of Modality 4, wherein one or more bisphenol compounds are selected from the group consisting of bisphenol A, bisphenol B, bisphenol E, bisphenol F and bisphenol AF.

[0078] Embodiment 6. The hybrid primer of any of Embodiments 1 to 5, wherein the isocyanate-containing compound is an aliphatic isocyanate-containing compound or an aromatic isocyanate-containing compound, either of which may be blocked or unblocked.

[0079] Embodiment 7. The hybrid primer of any of Embodiments 1 to 6, wherein the isocyanate-containing compound is a water-dispersible aromatic or aliphatic polyisocyanate.

[0080] Embodiment 8. The hybrid primer of any of Embodiments 1 to 6, wherein the isocyanate-containing compound is a member selected from the group consisting of hexamethylene diisocyanate (HDI), deisophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), and blocked derivatives thereof.

[0081] Embodiment 9. A water-based hybrid primer composition comprising the hybrid primer of any of Embodiments 1 to 8 in an aqueous medium.

[0082] Embodiment 10. A method for preparing the hybrid primer of any of Embodiments 1 to 8, comprising: Mix the epoxy resin, polyurethane dispersion, and isocyanate-containing compound in an aqueous medium at a temperature and for a time sufficient to cause a reaction between the epoxy resin, polyurethane dispersion, and isocyanate-containing compound, to form the cross-linked network.

[0083] Further modifications and variations of the present invention are possible in view of the above teachings. Therefore, it should be understood Petition 870250094414, dated 10 / 15 / 2025, page 34 / 45 / 25, which states that, within the scope of the appended claims, the invention can be practiced in a manner other than that specifically described in the present invention. Petition 870250094414, dated 10 / 15 / 2025, pages 35 / 45

Claims

1 / 3 CLAIMS 1. Hybrid primer, characterized in that it comprises a cross-linked network of polymers formed from an epoxy resin, a polyurethane dispersion and an isocyanate-containing compound.

2. Hybrid primer according to claim 1, characterized in that the polyurethane dispersion comprises hydroxyl and carboxyl functional groups that are reactive with one or both of the isocyanate-containing compound and the epoxy resin.

3. Hybrid primer according to claim 1, characterized in that the polyurethane dispersion comprises a polyurethane formed from one of an aliphatic diisocyanate or an aromatic diisocyanate, one or more diols or polyols, a catalyst and, optionally, one or more additives selected from the group consisting of chain extenders and crosslinkers.

4. Hybrid primer according to claim 1, characterized in that the epoxy resin is formed from epichlorohydrin units and one or more bisphenol compounds.

5. Hybrid primer according to claim 4, characterized in that one or more bisphenol compounds are selected from the group consisting of bisphenol A, bisphenol B, bisphenol E, bisphenol F and bisphenol AF.

6. Hybrid primer according to claim 1, characterized in that the isocyanate-containing compound is either an aliphatic isocyanate-containing compound or an aromatic isocyanate-containing compound, either of which can be blocked or unblocked.

7. Hybrid primer according to claim 1, characterized in that the isocyanate-containing compound is a water-dispersible aromatic or aliphatic polyisocyanate. Petition 870250094414, dated 10 / 15 / 2025, p. 36 / 45 2 / 3 8. Hybrid primer according to claim 1, characterized in that the isocyanate-containing compound is a selected member of the group consisting of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4'-diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), and blocked derivatives thereof.

9. Water-based hybrid primer composition, characterized in that it comprises the hybrid primer, as defined in claim 1, in an aqueous medium.

10. Method for preparing the hybrid primer, as defined in claim 1, characterized in that it comprises: mixing the epoxy resin, the polyurethane dispersion and the isocyanate-containing compound in an aqueous medium at a temperature and for a time sufficient to cause a reaction between the epoxy resin, the polyurethane dispersion and the isocyanate-containing compound, to form the cross-linked network.

11. Method according to claim 10, characterized in that the polyurethane dispersion comprises hydroxyl and carboxyl functional groups that are reactive with one or both of the isocyanate-containing compounds and the epoxy resin.

12. Method according to claim 10, characterized in that the polyurethane dispersion comprises a polyurethane formed from one of an aliphatic diisocyanate or an aromatic diisocyanate, one or more diols or polyols, a catalyst and, optionally, one or more additives selected from the group consisting of chain extenders and crosslinkers.

13. Method according to claim 10, characterized in that the epoxy resin is formed from epichlorohydrin units and one or more bisphenol compounds. Petition 870250094414, dated 10 / 15 / 2025, page 37 / 45 3 / 3 14. Method according to claim 13, characterized in that one or more bisphenol compounds are selected from the group consisting of bisphenol A, bisphenol B, bisphenol E, bisphenol F and bisphenol AF.

15. Method according to claim 10, characterized in that the isocyanate-containing compound is either an aliphatic isocyanate-containing compound or an aromatic isocyanate-containing compound, either of which can be blocked or unblocked.

16. Method according to claim 10, characterized in that the isocyanate-containing compound is a water-dispersible aromatic or aliphatic polyisocyanate.

17. Method according to claim 10, characterized in that the isocyanate-containing compound is a selected member of the group consisting of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dicyclohexylmethane 4,4'-diisocyanate (HMDI), tetramethylxylylene diisocyanate (TMXDI), and blocked derivatives thereof. Petition 870250094414, dated 10 / 15 / 2025, pp. 38 / 45

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