Matting agent and polyurethane coating composition containing same

Abstract

The present technology provides a matting agent for a polyurethane coating composition, the matting agent having a BET surface area to pore volume ratio (SA:PV) of 160 m 2 The polyurethane coating composition includes a porous silica particle having a viscosity of 1000 s / mL or less. The present technology further provides a polyurethane coating composition and a cured coating thereof. The composition includes a matting agent, a polyol, a crosslinking agent, and a catalyst.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 255,349, filed October 13, 2021, which is incorporated by reference herein in its entirety.

[0002] The present invention relates generally to the field of matting agents and polyurethane coatings containing matting agents. [Background technology]

[0003] A coating material is a product that is a mixture of volatile and non-volatile components, usually in the form of a liquid, paste, or powder, that forms a layer or coating from the non-volatile components when applied to a substrate and cured under defined conditions to remove the volatile components. Coating materials can include at least one non-volatile film-forming substance, usually called a binder or resin, as well as other conventional ingredients such as solvents, diluents, extenders, pigments, dyes, and / or additives.

[0004] Coating materials can be provided as single-pack systems (one component) or multi-pack systems (two or more separate components). In multi-pack systems, two or more separate components must be mixed according to the coating product specifications before application. Multi-pack coating systems are primarily two-component systems in which the components include a binder and a hardener (also called a curing agent).

[0005] After application, the coating material forms a solid layer or coating by changing from a liquid or paste state to a solid state under defined environmental conditions, except for powder coatings, which undergo a change from solid to liquid and back to solid. This process results in a layer or coating having protective, decorative, and / or other functional or desired properties.

[0006] Typically, the coating process includes at least a drying step and may include a curing step. In the drying step, the volatile components of the coating material evaporate, resulting in the solidification of the layer. In the curing step, the hardener increases the molecular size of the resin by chemical reaction. Both steps may be performed in parallel. Depending on the coating technique, the hardener is added to the resin component before application (two-pack or multi-pack products) or is mixed into the resin component in its latent state (single pack) or is part of the environmental conditions during the curing step (single pack). The hardener may further be a latent hardener that needs to be activated during the curing step to ensure that the resin and the hardener react chemically to form a layer of the desired properties. Latent hardeners do not react with the resin under storage conditions, thus allowing a good shelf life, but can be activated by a stimulus during the processing step. Activation can be performed at elevated temperatures.

[0007] Single-pack coating systems may be preferred over multi-pack systems because single-packs allow for the avoidance of mixing errors, ease of handling, and process implementation (e.g., no mixing equipment required). However, conventional single-pack coating products often have limitations regarding product durability, e.g., lower mechanical properties and / or lower chemical resistance compared to multi-pack systems. This is because the formation of the coating layer is governed by physical drying, i.e., the evaporation of the volatile portion of the coating material due to the absence of a curing agent. The reaction rate determines important coating material properties such as the cure time (i.e., the time between the application of the coating material and the preparation for the expected application) and pot life of the multi-pack system. To combine the advantages of single-packs (ease of processing) with multi-pack (durability) coating products, the use of latent curing agents in the coating material (e.g., blocked isocyanates in polyurethane coating compositions) has been developed.

[0008] Generally, polyurethane coating compositions include a binder (e.g., polyol) containing hydroxyl functional groups and a curing agent containing isocyanate functional groups. Both functional groups must be available during the curing process to ensure a chemical reaction. The chemical reaction between the curing agent and the binder results in a thermosetting type polymer bonded mainly by carbamate bonds (i.e., urethane bonds). In the presence of water, the polymer may be partially bonded by carbamide bonds (i.e., urea bonds). Due to the relatively low reaction rate between polyols and isocyanates at lower temperatures (e.g., room temperature), polyisocyanates are usually catalyzed to adapt the reaction rate. The most common catalysts are metal complexes (including, but not limited to, tin-based dibutyltin dilaurate (DBTL)) and / or tertiary amines. Depending on the chemical nature of the catalyst, the isocyanate functional groups, the hydroxyl functional groups, or both can be activated to increase the chemical reaction rate.

[0009] Blocked isocyanates in combination with polyol-type resins are widely used in polyurethane coating compositions, acting as latent curing agents. The isocyanates may be deblocked by elevated temperatures after the curing agent becomes active and reacts with the polyol resin to form a coating layer. The deblocking temperature is determined by various parameters, but is primarily determined by the chemical nature of the blocking agent, the presence of a catalyst, and the presence of polyol.

[0010] Therefore, single-pack polyurethane-type products using blocked isocyanates can achieve similar durability as conventional multi-pack polyurethane coating products while maintaining ease of handling. However, high-bake coating systems (e.g., coil coating, can coating, automotive coating, and wire coating) require very fast curing coating systems with high automation and high optimization for production speed. In continuous processes such as coil coating lines, high levels of productivity may be lost if the line speed must be reduced due to slow cure response.

[0011] Catalyst also plays an important role in such polyurethane coating system. Typically, the catalyst is a Lewis acid catalyst. The catalyst ensures fast curing by lowering the deblocking temperature and / or increasing the reaction rate between polyol and isocyanate. The lowering of the deblocking temperature has several advantages, including faster production line speed utilization for continuous process and / or lower yellowing tendency. Therefore, the fast curing response of the coating product of blocked isocyanate polyurethane, which is directly related to the catalyst activity, is of utmost importance in such process.

[0012] The need for fast cure response often presents an additional challenge when there is a need to provide a specified gloss target in the final coating. The traditional method of reducing the gloss of a coating is to use a solid matting agent, generally called matting. It is generally known that silica-based matting agents are the most effective matting agents for reducing the gloss of coatings in general, and polyurethane coatings in particular. However, the increase in silica matting agents can cause undesirable side effects in coating materials.

[0013] For example, in polyurethane coating systems, an increase in silica matting agent can cause catalyst deactivation. This is particularly problematic in processes requiring severe catalyst activity, such as polyurethane-type coil coating applications. The market is trending toward lower gloss polyurethane coil coating systems that require higher loadings of matting agent. In this case, an increase in silica matting agent can deactivate the catalyst to the extent that it either results in an under-cured coating or requires a significantly increased amount of catalyst resulting in a higher cost coating.

[0014] To minimize the need to increase the silica matting agent and to avoid catalyst deactivation, organic matting agents are often used in combination with the silica matting agent. Although organic matting agents help maintain acceptable catalyst activity, they tend to be less efficient and more expensive than traditional silica matting agents, increasing the costs associated with the coating system.

[0015] Thus, there is a need for matting agents that are cost effective and provide acceptable gloss levels while simultaneously providing high cure response in coating compositions, particularly catalyzed polyurethane coating compositions. Summary of the Invention

[0016] The present technology provides a matting agent for polyurethane coating compositions. The matting agent has a BET surface area to pore volume ratio (SA:PV) of 160 m 2 / mL or less. In any embodiment, the matting agent comprises porous silica particles having a BET surface area to pore volume ratio (SA:PV) of 150 m 2 In any embodiment, the SA:PV is about 80 ml / mL or less. 2 / mL ~ approx. 160m 2 / mL, approx. 80m 2 / mL ~ approx. 150m 2 / mL, or about 80m 2 / mL ~ approx. 140m 2In one embodiment, the matting agent provides a cure response in the polyurethane coating composition of at least 100, at least 200, at least 250, or at least 300 double rubs as determined by MEK double rub test.

[0017] In another aspect, the present technology provides a polyurethane coating composition comprising a matting agent as disclosed and described herein. In any embodiment, the polyurethane coating composition may be a polyurethane coil coating composition comprising a matting agent as disclosed and described herein. In any embodiment, the polyurethane coating composition provides excellent cure response and good matting efficiency without the need for a deleterious increase in catalyst. In any embodiment, the present technology provides a more cost-effective polyurethane coating composition with excellent cure response because it can provide good matting efficiency without the need to incorporate an organic matting agent.

[0018] The present technology further provides a coated substrate comprising a cured polyurethane coating comprising a matting agent as disclosed and described herein. In any embodiment, the coated substrate may comprise at least one surface coated with the polyurethane coating composition as disclosed herein. In any embodiment, the substrate may be a metal substrate. In any embodiment, the substrate may be a metal coil.

[0019] In yet another aspect, the present technology provides a process for preparing a polyurethane coating composition comprising the matting agent disclosed and described herein and having improved curing response.In any embodiment, the polyurethane coating composition may have excellent curing response and high matting efficiency without the need for detrimental increase in catalyst.

[0020] The present technology provides a process for coating a substrate with a polyurethane coating composition comprising a matting agent as disclosed and described herein. In any embodiment, the composition may be metallic. In any embodiment, the metallic substrate may be in the form of a coil or a can. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Definitions of certain terms used herein are provided below: Unless otherwise defined, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs.

[0022] The following terms are used throughout, as defined below.

[0023] As used herein and in the appended claims, in the context of describing elements (particularly in the context of the claims that follow), singular articles such as "a," "an," "the," and similar referents should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein can be performed in any suitable order, unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "etc.") provided herein is intended merely to better illustrate the embodiments and does not impose limitations on the scope of the claims, unless otherwise specified. No language in this specification should be construed as indicating any non-claimed element as essential.

[0024] "About" in reference to a number is generally deemed to include numbers within a range of 1%, 5%, or 10% in either direction (greater or smaller) of the number, unless expressly stated otherwise or otherwise clear from the context (except where such number is less than 0% or exceeds 100% of its possible value).

[0025] The methyl ethyl ketone (MEK) double rub test refers to a test according to standard EN 13523-11:2011, in which the resistance to solvents (rubbing test) is determined. The MEK test can be carried out by applying 60 μm of a polyurethane coating composition adjusted to a gloss of 10 ± 2 GU at 60 ° onto a hot-dip galvanized steel panel pretreated with Gardobond® X 4744 (purchased ready-made from Chemetall Group) to prepare the panel. The coated panel can be cured in a laboratory hot air oven mold (from MATHIS AG) until a peak metal temperature of 230 ° C (measured in situ by an infrared pyrometer) is reached. Typical durations can range from about 48 to about 50 seconds. The MEK double rub can be carried out using a LINEARTESTER 249 (from Erichsen). The double rub count value is based on the rub resistance (i.e., the counting stops after the metal substrate is visible).

[0026] The surface area ("SA") of porous silica particles useful as matting agents in the present technology may be determined by nitrogen adsorption measurements on a Micromeritics ASAP 2420 instrument using the Brunauer Emmett Teller ("BET") theory, or may be measured by an equivalent instrument. The SA value is obtained by the ASAP 2420 software V2.09 from the evaluation of the linear region of the adsorption isotherm according to the theory of Brunauer, Emmett and Teller (see also Brunauer, S., Emmett, PH and Teller, E.: "Adsorption of gases in multimolecular layers", J. Amer. Chem. Soc., 60, 309 (1938), which is incorporated herein by reference).

[0027] The pore volume ("PV") of porous silica particles useful as matting agents in the present technology is determined by adsorption measurements with non-reactive gases (e.g., N2) on a Micromeritics ASAP 2420 instrument. As will be understood by those skilled in the art, PV can be determined by using any other equivalent instrument. Using the ASAP 2420, the amount of non-reactive gas adsorbed is volumetrically determined on the activated sample as a function of equilibrium partial pressure p / p0 at a temperature of 77K. The activated sample is prepared by drying 1 g of sample in an open weighing bottle in a convection drying oven at 200°C for about 2 hours. The weighing bottle is then closed and allowed to cool to ambient temperature in a desiccator. The dried sample is activated under vacuum for about 2 hours using the degassing unit of the ASAP 2420 instrument. PV values ​​were determined for the pore size range corresponding to a relative pressure of p / p up to 0.995 by ASAP 2420 software V2.09 according to the theory of Barrett, Joyner and Halenda (BJH) (see also Barrett, EP, Joyner, LG, Halenda, PP: "The determination of pore volume and area distribution in porous substances", J. Am. Chem. Soc. 73 (1951) 373-380, which is incorporated herein by reference).

[0028] The particle size of the porous silica particles of this embodiment can be measured by different physical methods known in the art, including but not limited to laser light scattering method(s). The median particle size of the porous silica particles disclosed and described herein was measured using a Malvern Mastersizer 2000 static laser light scattering instrument. As will be understood by those skilled in the art, other static laser light scattering instruments can be used as well.

[0029] "Median particle size" or "median particle size of volume distribution" (also called "D(v,0.5)" or "D50") refers to the particle size in microns at which 50% of the sample is smaller than its median particle size and 50% is larger than its median particle size. For example, sample preparation involves adding approximately 1 g of sample and 100-120 mL of deionized water to a 150 mL beaker. The tip of an ultrasonic resonator (Branson Sonifier W250D) is immersed 2 cm into the fluid at the center of the beaker. Sonication can be performed for 10 seconds at a power setting of 55%. A sufficient amount of the resulting slurry is then immediately transferred to the test cell of the Mastersizer instrument according to the requirements for concentration / obscuration in the user manual. The result from the analysis is the relative distribution of the volume of particles in a range of size classes. The results are used to calculate the size distribution and interpolate from the fit curve of the size values ​​to obtain the median particle size.

[0030] As mentioned above, silica matting agents are used to reduce gloss in polyurethane coatings, but silica matting agents can cause deactivation of the catalyst required to cure the coating. This results in a poorly cured coating with unacceptable performance or requires a larger amount of catalyst. At a particular SA to PV ratio, i.e., SA:PV is 160m, the silica matting agent can cause deactivation of the catalyst required to cure the coating. 2 It has been surprisingly discovered that silica matting agents in amounts of 0.15g / mL or less do not deactivate the catalyst and provide a fast cure response.

[0031] The mechanism of catalyzed urethane cure has been suggested to work through activation of polyol alcohols by coordinating with the catalyst. (Houghton et al (Journal of Organometallic Chemistry 518, 1996, 21-27)). Without wishing to be bound by theory, it is speculated that the catalyst may instead coordinate with -OH on the silica matting agent surface, making the catalyst unavailable for the cure reaction. Therefore, to maximize the cure response, it may be necessary to minimize the number of -OH groups available from the silica matting agent. Thus, the total number of -OH groups from the silica matting agent should be directly proportional to the SA of the silica matting agent and inversely proportional to the PV of the silica matting agent used in the coating to achieve a particular gloss.

[0032] Therefore, this technology has a SA to PV ratio of 160m 2 The present technology further provides a polyurethane coating composition comprising a matting agent as disclosed and described herein, as well as a coated substrate comprising a cured coating of the polyurethane coating composition.

[0033] In any embodiment, the porous silica particles used as matting agents in the present technology have a SA:PV of about 155 m 2 In any embodiment, the porous silica particles may have a SA:PV of about 150 ml / mL or less. 2 In any embodiment, the porous silica particles may have a SA:PV of about 145 ml / mL or less. 2 In any embodiment, the SA:PV may be about 140 ml / mL or less. 2 / mL or less, approximately 135m 2 / mL or less, or about 130m 2 In any embodiment, the SA:PV may be at least about 80 ml / mL or less. 2 In any embodiment, the SA:PV may be at least about 85 ml / mL. 2 / mL, at least about 90m2 / mL, at least about 95m 2 / mL, or at least about 100m 2 In any embodiment, the SA:PV may be about 80 ml / mL. 2 / mL ~ approx. 160m 2 In any embodiment, the SA:PV may be about 80 ml / mL. 2 / mL ~ approx. 150m 2 In any embodiment, the SA:PV may be about 80 ml / mL. 2 / mL ~ approx. 140m 2 In any embodiment, the SA:PV may be about 85 ml / mL. 2 / mL ~ approx. 155m 2 / mL, approx. 90m 2 / mL ~ approx. 145m 2 / mL, approx. 95m 2 / mL ~ approx. 135m 2 / mL, or about 100m 2 / mL ~ approx. 130m 2 / mL.

[0034] In any embodiment, the porous silica particles used as a matting agent in the present technology may have a PV of at least about 0.4 mL / g as determined by nitrogen porosimetry. In any embodiment, the PV may be at least about 0.6 mL / g or at least about 0.8 mL / g. In any embodiment, the PV may be about 3.5 mL / g or less. In any embodiment, the PV may be about 3.1 mL / g or less. In any embodiment, the PV may be about 2.5 mL / g or less, about 2.3 mL / g or less, or about 2.1 mL / g or less. In any embodiment, the porous silica particles may have a PV of about 0.4 mL / g to about 3.5 mL / g. In any embodiment, the porous silica particles can have a PV of about 0.6 mL / g to about 3.1 mL / g, about 0.8 mL / g to about 3.1 mL / g, about 0.8 mL / g to about 2.5 mL / g, about 0.8 mL / g to about 2.3 mL / g, or about 0.8 mL / g to about 2.1 mL / g.

[0035] In any embodiment, the porous silica particles used as a matting agent in the present technology have a diameter of about 525 mm as determined by nitrogen porosimetry. 2 In some embodiments, the SA is about 465 m / g or less. 2 / g or less, approximately 450m 2 / g or less, approximately 425m 2 / g or less, approximately 400m 2 / g or less, approximately 375m 2 / g or less, approximately 350m 2 / g or less, or about 320m 2 In any embodiment, the porous silica particles have a molecular weight of at least about 60 μm / g or less as determined by nitrogen porosimetry. 2 In any embodiment, the SA may be at least about 80 m / g. 2 / g, at least about 100m 2 / g, at least about 110m 2 / g, or at least about 120m 2 In any embodiment, the SA may be about 60 m / g. 2 / g ~ approx. 525m 2 / g, approx. 80m 2 / g ~ approx. 465m 2 / g, approx. 90m 2 / g ~ approx. 450m 2 / g, about 100m 2 / g~about 400m 2 / g, approx. 110m 2 / g ~ approx. 350m 2 / g, or about 120m 2 / g ~ approx. 320m 2 / g.

[0036] In any embodiment, the porous silica particles useful as a matting agent may have a median particle size of about 1 μm to about 30 μm as determined by laser light diffraction. In any embodiment, the porous silica particles may have a median particle size of about 3 μm to about 15 μm or about 5 μm to about 15 μm. In any embodiment, the porous silica particles may include at least one surface hydroxyl group. In any embodiment, the matting agent includes a plurality of surface hydroxyl groups. In any embodiment, the porous silica particles may include silica gel, precipitated silica, pyrogenic silica particles, or a combination of two or more thereof. In any embodiment, the porous silica particles may include silica gel. In any embodiment, the porous silica particles may include precipitated silica. In any embodiment, the porous silica particles may include pyrogenic silica particles.

[0037] The preparation of the different types of silica discussed herein is widely described in the literature and is well known by those skilled in the art, for example in Handbook of Porous Solids, 2008, Volume 3, edited by Ferdi Schueth, Kenneth SWSing and Jens Weitkamp, ​​p.1543-1591, John Wiley & Sons, which is incorporated herein by reference.

[0038] Precipitated silicas are generally made using a wet process by acidifying sodium silicate or other alkali or alkaline earth metals under conditions such that the primary particles formed coagulate into clusters. Reaction conditions are utilized such that the liquid phase is not entirely surrounded by the solid phase. Sulfuric acid is usually used for the reaction (see, for example, DE 1299617), but other acids such as hydrochloric acid (see, for example, EP 170578), organohalosilanes (see, for example, RKIler, The Colloid Chemistry of silica and silicas, Cornell University Press, New York, 1955, Chapter 5), carbon dioxide (see, for example, U.S. Pat. No. 4,260,454), or a combination of carbon dioxide and mineral acids have been used. However, almost all commercial routes are based on the sulfuric acid route. The precipitation is mainly carried out under alkaline conditions. The choice of stirring, duration of precipitation, rate of addition of the reactants, their temperature, concentration, and pH can change the properties of the silica. Under standard conditions, a sodium silicate (or alkali metal silicate) solution and an acid are fed simultaneously to a stirred vessel containing water. The primary silica particles grow to a size larger than 4-5 nm and are coagulated into aggregates by the sodium ions coming from the sodium silicate. In the course of precipitation, a three-dimensional network is formed. The formation of a gel phase is avoided by stirring at high temperatures. In the next stage, the precipitated silica slurry is washed to remove soluble salts. The washing conditions, although important, have less influence on the final product properties than in the case of silica gel. Different filter types can be used, such as filter presses, rotary filters or belt filters. The obtained filter cake is subsequently dried, for example having a solids content of 15-25%. The most common drying techniques are fast drying procedures, such as spray drying, and slow drying procedures, such as rotary drying, which give rise to different particle shapes, degrees of agglomeration and, to a lesser extent, porosity (see, for example, DE 3639845). The dried silica may be subjected to grinding and classification steps to obtain a specific particle size distribution.If necessary, additional steps may be included to further modify the silica, for example to introduce specific hydrophobic properties and / or to introduce other functional groups.

[0039] Silica gel, a porous solid amorphous form of hydrous silicon dioxide, has the nominal chemical formula of Si02·xH20. It is composed of randomly bonded spherical polymeric silicate particles, the primary particles. The properties of silica gel are the result of the aggregation state of the primary particles and their surface chemistry. The SA, porosity and surface chemistry can be controlled during the manufacturing process. Silica gel can be manufactured according to the Graham wet process, which consists of releasing silicic acid from a concentrated solution of sodium silicate by a strong mineral acid such as hydrochloric acid or sulfuric acid (see, for example, U.S. Pat. No. 1,297,724). The control of the pore structure is of great practical importance. Variations in process conditions such as pH, electrolyte content, pore solvent, and temperature during the different stages of gel synthesis have a significant effect on the pore structure of the final gel. Depending on the raw materials used in the gel synthesis, the hydrogel contains a certain amount of electrolyte, acid or base. These components can be removed in a washing step. In addition to the washing conditions, conditions during subsequent aging such as pH, temperature, aging time, number of aging steps, and solvent type are important for the pore structure evolution. The drying process results in the formation of a xerogel. The drying conditions have a large effect on the structure of the final gel. In the first stage, the gel shrinks to accommodate the liquid lost by evaporation. The largest changes in volume, weight, density, and pore structure occur during this stage. The drying rate also influences the gel network shrinkage. In the second stage, the pores are emptied. Fast drying results in less shrinkage than slow drying (CJ Brinker, Transactions ACA, 1991, 27, 163).

[0040] Pyrogenic silica, also called fumed or thermal silica, can be produced by a high-temperature hydrolysis process for the production of very finely sized oxides (see DE 762723). The raw materials in this process are chlorosilanes which are hydrolyzed in an oxygen-hydrogen flame. The silica is formed in an aerosol and subsequently separated from the gas phase. Residual hydrogen chloride, which is still adsorbed on the silica surface, can be removed using water vapor or air. The properties of pyrogenic, or fumed, or thermal silica can be controlled by varying the reaction parameters such as the flame composition and temperature. This process produces primary particle sizes of 7-40 nm and a solubility of 50-600 nm. 2 This produces silica with an SA of 0.1 to 0.1 g / g. The primary particles form aggregates by intergrowth and agglomerate by cohesive forces. An alternative thermal process to flame hydrolysis is the electric arc process, in which quartz sand is reduced with coal to give silicon monoxide in the gas phase, which is then oxidized to amorphous silica.

[0041] In any embodiment, the matting agent comprises porous precipitated silica and may be prepared by any conventional precipitation process to provide a final porous silica particle having the disclosed SA:PV ratio. In any embodiment, the matting agent may be produced by forming precipitated inorganic silica particles in a reaction mixture, separating the precipitated inorganic silica particles from the liquid in the reaction mixture, washing the precipitated inorganic silica particles to produce washed precipitated inorganic silica particles, and rapidly drying the washed precipitated inorganic silica particles to form dried porous inorganic silica particles. In any embodiment, the dried porous inorganic silica particles may be ground to a desired average particle size. In any embodiment, the rapid drying may be at a temperature of about 300°C to about 350°C for about 15 seconds or less (e.g., using a spin flash dryer). In a preferred embodiment, the precipitated silica useful in the present technology may be produced by the method disclosed and described in U.S. Pat. No. 4,590,052(B1), which is incorporated herein by reference.

[0042] In an optional embodiment, the polyurethane coating composition comprises a matting agent as disclosed herein. In an optional embodiment, the polyurethane coating composition may further comprise a polyol, a crosslinker, and a catalyst.

[0043] In any embodiment, the polyol may include any known polyol used to prepare polyurethane coatings. Non-limiting polyols include polyacrylate polyols, polyester polyols, polyether polyols, polyurethane polyols, polyurea polyols, polyetherols, polycarbonates, polyester-polyacrylate polyols, polyester-polyurethane polyols, polyurethane-polyacrylate polyols, polyurethane-modified alkyd resins, fatty acid modified polyester-polyurethane polyols, copolymers with allyl ethers, and copolymers and graft polymers thereof. In any embodiment, the polyol may include polyols for polyurethane coatings as disclosed in US Patent Application Publication No. 2005 / 0288450 (hereby incorporated by reference).

[0044] In any embodiment, the crosslinker may be an isocyanate, preferably a polyisocyanate. The polyisocyanate may be any known polyisocyanate useful in the preparation of polyurethane coatings, including diisocyanates and / or triisocyanates. Examples of isocyanate monomers are as follows (isomers not specified): hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hydrogenated methylene diphenyl diisocyanate (HDI), methyl ethyl ketone (MTE), methyl ... 12MDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), trimethyl-1,6-diisocyanatohexane, tetramethyl xylylene diisocyanate (TMXDI), triisocyanatononane (TIN), triphenylmethane 4,4,4-triisocyanate, tris(p-isocyanatophenyl)thiophosphate. Non-limiting polyisocyanates contain two or more isocyanate groups and can be derived from aromatic, aliphatic, cycloaliphatic, and / or other monomeric groups that can be functionalized with isocyanate groups. In any embodiment, the crosslinker may include a polyol for polyurethane coatings as disclosed in U.S. Patent Application Publication No. 2005 / 0288450, which is incorporated herein by reference.

[0045] In any embodiment, the crosslinking agent may be an at least partially blocked polyisocyanate. Non-limiting examples include polyisocyanates having isocyanate groups blocked with a thermally dissociable blocking agent, such as an oxime compound, an acid amide compound, an amine compound, an active methylene compound, and / or a pyrazole compound. Another non-limiting example may be a blocked polyisocyanate obtained from the reaction of components including a) at least one polyisocyanate selected from an aromatic polyisocyanate, an aliphatic polyisocyanate, an alicyclic polyisocyanate, and / or a polyisocyanate-functional polymer, and b) at least one β-diketone. Exemplary blocked polyisocyanates may include hexamethylene diisocyanate (HDI) type aliphatic polyisocyanates blocked with methyl ethyl ketone oxime (MEKO), such as Desmodur® BL 3175 (available from Covestro).

[0046] Summary of Exemplary Blocked Polyisocyanate Curing Agent Products: [Table 1]

[0047] In any embodiment, the catalyst may include a Lewis acid catalyst. In any embodiment, the Lewis acid catalyst may include a tin catalyst, a bismuth catalyst, a zinc catalyst, or a combination of two or more thereof. Non-limiting examples of tin catalysts include dibutyltin dilaurate (DBTL), dioctyltin dilaurate (DOTL), dioctyltin dithioglycolate, dioctyltin diacetate (DOTA), dibutyltin diacetate (DBTA), dioctyltin dinonanoate, dioctyltin dicarboxylate, dioctyltin carboxylate, or a combination of two or more thereof. Non-limiting examples of bismuth catalysts include bismuth dicarboxylate. Non-limiting examples of zinc catalysts include zinc neodecanoate.

[0048] In any embodiment, the polyurethane coating composition disclosed and described herein can be produced by any known method for making polyurethane-based coating compositions. In any embodiment, the polyurethane coating composition can be produced by combining and mixing the matting agent with the composition comprising the polyol, crosslinker, and catalyst disclosed and described herein using conventional means for forming a polyurethane-based coating composition. In any embodiment, the polyurethane coating composition can be produced by any method such as those disclosed in U.S. Patent Application Publication No. 2005 / 0288450 (herein incorporated by reference).

[0049] In any embodiment, the polyurethane coating composition may include from about 10% to about 75% by weight (including from about 15% to about 60% by weight, or from about 20% to about 50% by weight) of polyol. In any embodiment, the polyurethane coating composition may include from about 0.001% to about 5% by weight (including from about 0.01% to about 3% by weight, or from about 0.1% to about 1% by weight) of catalyst. In any embodiment, the polyurethane coating composition may include from about 1% to about 25% by weight (including from about 3% to about 20% by weight, or from about 5% to about 15% by weight) of crosslinker.

[0050] In any embodiment, the polyurethane coating composition can include a matting agent in any amount sufficient to provide a cured coating exhibiting a 60° gloss of about 80 or less. For example, the polyurethane coating composition can include from about 0.1% to about 15% by weight, including from about 1% to about 10% by weight, of the matting agent. In any embodiment, the polyurethane coating composition can include from about 0% to about 50% by weight, including from about 5% to about 40% by weight, or from about 10% to about 30% by weight, of a pigment (e.g., titanium dioxide). In any embodiment, the polyurethane coating composition can include from about 0.1% to about 60% by weight, including from about 5% to about 50% by weight, or from about 10% to about 40% by weight, of a solvent.

[0051] In any embodiment, the polyurethane coating composition may include any other known components conventionally included in polyurethane coating compositions, including, but not limited to, solvents, diluents, extenders, pigments, dyes, and / or additives. In any embodiment, the polyurethane coating composition may include any additional components as disclosed in U.S. Patent Application Publication No. 2005 / 0288450, which is incorporated herein by reference. In any embodiment, the polyurethane coating composition may include any components as disclosed in U.S. Patent Application Publication No. 2005 / 0288450, which is incorporated herein by reference, in the amounts disclosed therein.

[0052] The present technology further provides a method for preparing a coated substrate comprising applying a layer of the polyurethane coating composition disclosed and described herein to a substrate as disclosed and described herein. In any embodiment, the method may further comprise curing the layer of the polyurethane coating composition to form a coating on at least the surface of the substrate. In any embodiment, the curing may comprise removing volatiles and / or crosslinking the polyol.

[0053] In any embodiment, the substrate coated by the polyurethane coating composition provided herein may be a metal, such as iron and iron alloys, steel and steel alloys, copper and copper alloys, tin and tin alloys, aluminum and aluminum alloys, zinc and zinc alloys. The metal may be coated with another metal layer, such as hot-dip galvanized zinc. The metal may be artificially treated to create a specific pretreatment and / or passivation layer. In any embodiment, the substrate may be a metal coil.

[0054] In any embodiment, the substrate may be treated using any conventional coating technique (e.g., roll coating, doctor blading, spraying, etc.) to form a layer or coating on the substrate. The polyurethane coating is then cured under conditions sufficient to remove any volatile components and form a cured polyurethane coating on the substrate. In any embodiment, the thickness of the cured polyurethane coating may vary depending on the intended application. In any embodiment, the cured polyurethane coating for coil coating applications may have a thickness of about 1 μm to about 120 μm, including about 10 μm to about 50 μm or about 15 μm to about 35 μm.

[0055] In any embodiment, the cured polyurethane coating may have a 60° gloss of about 80 or less. In any embodiment, the cured polyurethane coating may have a 60° gloss of about 70 or less, including about 60 or less or about 50 or less.

[0056] In any embodiment, the matting agent enables a cure response of at least 100 double rubs in the polyurethane coating composition as determined by the MEK double rub test. In any embodiment, the matting agent enables a cure response of at least 200 double rubs in the polyurethane coating composition. In any embodiment, the matting agent enables a cure response of at least 250 double rubs or at least 300 double rubs in the polyurethane coating composition. In any embodiment, the polyurethane coating composition including the matting agent provides a cure response of at least 100 double rubs as determined by the MEK double rub test. In any embodiment, the polyurethane coating composition provides a cure response of at least 200 double rubs. In any embodiment, the polyurethane coating composition provides a cure response of at least 250 double rubs or at least 300 double rubs. In any embodiment, the coated substrate including the cured coating of the polyurethane coating composition exhibits a cure response of at least 100 double rubs as determined by the MEK double rub test. In any embodiment, the coated substrate including the cured coating of the composition exhibits a cure response of at least 200 double rubs. In any embodiment, the coated substrate exhibits a cure response of at least 250 double rubs or at least 300 double rubs.

[0057] In any embodiment, the cure response can be obtained without the need for an organic matting agent, which may be of methylenediaminomethylether polycondensate type (Deuteron MK), polyamide type (Orgasol range), polyurethane type, polymethylmethacrylate type, polystyrene type, HDPE wax type or mixtures thereof, depending on whether the cure temperature in the process is suitable for the respective organic matting agent.

[0058] The present technology further provides one-pack and two-pack coating kits. The two-pack kit may include a first pack containing a matting agent, a polyol, and a catalyst as disclosed and described herein, and a second pack containing a crosslinking agent. The one-pack kit may include a matting agent, a polyol, a catalyst, and a crosslinking agent (e.g., a blocked crosslinking agent) as disclosed and described herein. EXAMPLES

[0059] The present technology is further illustrated by the following examples, which should not be construed as limiting in any way.

[0060] The surface area of ​​the silica particles shown in the examples and tables was determined by nitrogen adsorption measurements on a Micromeritics ASAP 2420 instrument using BET theory. The pore volumes shown in the examples were determined by adsorption measurements with non-reactive gases (e.g., N2) on a Micromeritics ASAP 2420 instrument, as disclosed and described herein above. The MEK double rub test used to test the samples in the examples was performed according to the standard EN 13523-11:2011, as disclosed and described herein above.

[0061] Example 1: Polyurethane coating composition containing porous silica matting agent Polyurethane coating composition 1 (Example 1) was prepared having the components provided in Table 1. The coating composition was prepared by mixing components 1-6 (Table 1) in a water-cooled container and dispersing using a bead mill at 2500 RPM for 60 minutes. Components 7-10 (Table 1) were then slowly added at 2000 RPM and dispersed for 10 minutes to obtain the base coating composition. Finally, matting agent 1 (4.3 g) was added to the base coating composition (100 g) and dispersed using a high speed dissolver (dissolver blade diameter: 40 mm, 3000 RPM) for 10 minutes to obtain the polyurethane coating composition. The amount of matting agent added was determined to provide a target gloss of 10±2 GU at 60° using the matting curve. The matting curve was determined by adding 3 g-8 g of matting agent to 100 g of the base coating composition and measuring the gloss after curing. The amount of matting agent to achieve the target gloss was extrapolated from the resulting matting curve. [Table 2]

[0062] Following the same method, polyurethane coating compositions 2-10 were prepared (Examples 2-10) using the same components in Table 1, except that matting agent 1 was replaced with matting agents 2-10, respectively (Table 2). For each composition, the amount of each matting agent was determined by the matting curve according to the procedure above to achieve a target gloss of 10±2 GU at 60°. [Table 3]

[0063] The final coating compositions were each applied (60 μm wet film thickness) to hot-dip galvanized steel panels pretreated with Gardobond® X 4744 (purchased ready-made from Chemetall Group). The coated panels were cured in a laboratory hot air oven mold (from MATHIS AG) until a peak metal temperature of 230°C was reached (measured in situ by infrared pyrometer), which lasted for about 48-50 seconds. MEK double rub tests were then performed using a LINEARTESTER 249 (from Erichsen) as described herein. The double rub count values ​​were based on the rub resistance (i.e., the count was stopped after the metal substrate was visible). The results of the MEK double rub tests are shown in Table 3. The results were for a SA:PV ratio of 160 m 2 / mL or less matting agent is either "fair" or "good" and SA:PV is 140m 2 All coatings with less than 100 / mL of matting agent were rated "good." [Table 4] Good: MEK resistance >400; Possible: MEK resistance is 100-400, and Low: MEK resistance <100

[0064] Specific Embodiments

[0065] Embodiment 1. A matting agent for a polyurethane coating composition, comprising a BET surface area to pore volume ratio (SA:PV) of 160 m 2 / mL or less of porous silica particles.

[0066] Embodiment 2. The matting agent of embodiment 1, wherein the matting agent enables a cure response of at least 100 double rubs in a polyurethane coating composition as determined by MEK double rub test.

[0067] Embodiment 3.SA: PV is about 150m 2 / mL or less.

[0068] Embodiment 4.SA: PV is about 140m 2 4. The matting agent of embodiment 3, wherein the matting agent has a viscosity of 100:1 or less than 100:1.

[0069] Embodiment 5.SA: PV is at least about 80 m 2 / mL.

[0070] Embodiment 6.SA: PV is at least about 100 m 2 / mL.

[0071] Embodiment 7. The matting agent according to any one of embodiments 1 to 6, wherein the porous silica particles have a median particle size of about 1 μm to about 30 μm.

[0072] Embodiment 8. The matting agent according to embodiment 7, wherein the porous silica particles have a median particle size of about 3 μm to about 15 μm.

[0073] Embodiment 9. The matting agent according to any one of embodiments 1 to 8, wherein the porous silica particles comprise silica gel, precipitated silica, pyrogenic silica particles, or a combination of two or more thereof.

[0074] Embodiment 10. The matting agent according to any one of embodiments 9, wherein the porous silica particles comprise precipitated silica.

[0075] Embodiment 11. The matting agent of any one of embodiments 1 to 10, wherein the matting agent provides a cure response of at least 100 double rubs without the need for an organic matting agent.

[0076] Embodiment 12. A polyurethane coating composition comprising the matting agent according to any one of embodiments 1 to 11.

[0077] Embodiment 13. The coating composition of embodiment 12, wherein the composition exhibits a cure response of at least 100 double rubs as determined by MEK double rub test.

[0078] Embodiment 14. The coating composition of embodiment 13, wherein the composition exhibits a cure response of at least 200 double rubs as determined by MEK double rub test.

[0079] Embodiment 15. The coating composition of embodiment 13 or embodiment 14, wherein the cure response is obtained without the need for an organic matting agent.

[0080] Embodiment 16. The coating composition of any one of embodiments 12-15, further comprising a polyol, a crosslinker, and a catalyst.

[0081] Embodiment 17. The coating composition of embodiment 16, wherein the catalyst is a Lewis acid catalyst.

[0082] Embodiment 18. The coating composition of embodiment 17, wherein the Lewis acid catalyst comprises a tin, bismuth, or zinc catalyst.

[0083] Embodiment 19. The coating composition of embodiment 18, wherein the tin catalyst comprises dibutyltin dilaurate (DBTL), dioctyltin dilaurate (DOTL), dioctyltin dithioglycolate, dioctyltin diacetate (DOTA), dibutyltin diacetate (DBTA), dioctyltin dinonanoate, dioctyltin dicarboxylate, dioctyltin carboxylate, or a combination of two or more thereof.

[0084] Embodiment 20. The coating composition of embodiment 18 or embodiment 19, wherein the bismuth catalyst comprises a bismuth dicarboxylate.

[0085] Embodiment 21. The coating composition of any one of embodiments 18-20, wherein the zinc catalyst comprises zinc neodecanoate.

[0086] Embodiment 22. The coating composition of any one of embodiments 16 to 21, wherein the crosslinking agent is an isocyanate.

[0087] Embodiment 23. The coating composition of embodiment 22, wherein the isocyanate is a polyisocyanate.

[0088] Embodiment 24. The coating composition of embodiment 22 or embodiment 23, wherein the crosslinker is a blocked crosslinker.

[0089] Embodiment 25. A coated substrate comprising a cured coating of the coating composition of any one of embodiments 12-24.

[0090] Embodiment 26. The coated substrate of embodiment 25, wherein the substrate is metal.

[0091] Embodiment 27. The coated substrate of embodiment 25 or embodiment 26, wherein the substrate is a metal coil.

[0092] Embodiment 28. The coated substrate of any one of embodiments 25-27, wherein the cured coating exhibits a cure response of at least 100 double rubs as determined by MEK double rub testing.

[0093] Embodiment 29. The coated substrate of any one of embodiments 25 to 28, wherein the cured coating is from about 1 μm to about 120 μm thick.

[0094] Embodiment 30. A method for preparing a polyurethane coating composition according to any one of embodiments 12-24, comprising combining and mixing a matting agent according to any one of embodiments 1-11 with a composition comprising a polyol, a crosslinker, and a catalyst to form a polyurethane coating composition.

[0095] Embodiment 31. The method of embodiment 30, wherein the catalyst is a Lewis acid catalyst.

[0096] Embodiment 32 The method of embodiment 30 or embodiment 31, wherein the crosslinking agent is an isocyanate.

[0097] Embodiment 33. The method of embodiment 32, wherein the isocyanate is a polyisocyanate.

[0098] Embodiment 34 The method of embodiment 32 or embodiment 33, wherein the crosslinker is a blocked crosslinker.

[0099] Embodiment 35. A method for preparing a coated substrate according to any one of embodiments 25-29, comprising applying a layer of the polyurethane coating composition according to any one of embodiments 12-24 to a substrate.

[0100] Embodiment 36 The method of embodiment 35, further comprising removing volatile materials and curing the layer to form a coating on at least the surface of the substrate.

[0101] Embodiment 37. The method of embodiment 35 or 36, wherein the substrate is metal.

[0102] Embodiment 38. The method of any one of embodiments 35-37, wherein the substrate is a metal coil.

[0103] The present technology is not limited with respect to the specific embodiments described in this application, which are intended as single illustrations of individual aspects of the technology. As will be apparent to those skilled in the art, many modifications and variations of the present technology can be made without departing from its spirit and scope. Functionally equivalent methods and devices within the scope of the present technology will be apparent to those skilled in the art from the foregoing description, in addition to those recited herein. Such modifications and variations are intended to be within the scope of the present technology. It is to be understood that the present technology is not limited to specific methods, reagents, compounds, compositions, or biological systems, which may of course vary. It is also to be understood that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to be limiting.

[0104] Additionally, when features or aspects of the disclosure are described in terms of a Markush group, one of skill in the art will recognize that the disclosure is also thereby described in terms of any individual members or subgroups of members of the Markush group.

[0105] As will be understood by those of skill in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein encompass any and all possible subranges and combinations thereof. Any recited range can be readily recognized as fully descriptive and allowing for the same range to be subdivided into at least two, three, four, five, ten, etc. As a non-limiting example, each range discussed herein can be readily subdivided into a lower third, a middle third, an upper third, etc. Also, as will be understood by those of skill in the art, all terms such as "up to," "at least," "greater than," "less than," etc. refer to ranges that include the recited numbers and that can then be subdivided into subranges as previously discussed. Finally, as will be understood by those of skill in the art, a range includes each individual member. Thus, for example, a group having 1-3 atoms refers to groups having 1, 2, or 3 atoms. Similarly, a group having 1-5 atoms refers to groups having 1, 2, 3, 4, or 5 atoms, etc.

[0106] All patents, patent applications, provisional applications, and publications mentioned or cited in this specification are incorporated by reference in their entirety, including all figures and tables, to the extent not inconsistent with the explicit teachings of this specification.

Claims

1. A matting agent for polyurethane coating compositions having a BET surface area to pore volume ratio (SA:PV) of 160 m ２ / mL or less porous silica particles.

2. 10. The matting agent of claim 1, wherein said matting agent enables a cure response of at least 100 double rubs in said polyurethane coating composition as determined by an MEK double rub test.

3. SA: PV is about 150m ２ 10. The matting agent according to claim 1, wherein the total weight of the matting agent is 1000 ppm or

4. SA: PV is at least about 80m ２ / mL of the matting agent according to claim 3.

5. 10. The matting agent of claim 1, wherein the porous silica particles have a median particle size of from about 1 μm to about 30 μm.

6. 6. The matting agent of claim 5, wherein the porous silica particles have a median particle size of from about 3 μm to about 15 μm.

7. 10. The matting agent of claim 1, wherein the porous silica particles comprise silica gel, precipitated silica, pyrogenic silica particles, or a combination of two or more thereof.

8. 10. The matting agent of claim 1, wherein said matting agent provides a cure response of at least 100 double rubs without the need for an organic matting agent.

9. A polyurethane coating composition comprising the matting agent of claim 1.

10. 10. The coating composition of claim 9, wherein the composition exhibits a cure response of at least 100 double rubs as determined by the MEK double rub test.

11. 11. The coating composition of claim 10, wherein the cure response is achieved without the need for an organic matting agent.

12. 10. The coating composition of claim 9, further comprising a polyol, a crosslinker, and a catalyst comprising a Lewis acid catalyst including a tin, bismuth, or zinc catalyst.

13. 13. The coating composition of claim 12, wherein the Lewis acid catalyst comprises dibutyltin dilaurate (DBTL), dioctyltin dilaurate (DOTL), dioctyltin dithioglycolate, dioctyltin diacetate (DOTA), dibutyltin diacetate (DBTA), dioctyltin dinonanoate, dioctyltin dicarboxylate, dioctyltin carboxylate, or a combination of two or more thereof.

14. 13. The coating composition of claim 12, wherein the Lewis acid catalyst comprises a bismuth dicarboxylate.

15. 13. The coating composition of claim 12, wherein the Lewis acid catalyst comprises zinc neodecanoate.

16. The coating composition of claim 12 wherein the crosslinker is an isocyanate.

17. 17. The coating composition of claim 16, wherein the crosslinker is a blocked crosslinker.

18. A coated substrate comprising a cured coating of the coating composition of claim 9.

19. 20. The coated substrate of claim 18, wherein the cured coating is from about 1 μm to about 120 μm thick.

20. 10. A method for preparing the polyurethane coating composition of claim 9, comprising combining and mixing the matting agent of claim 1 with a composition comprising a polyol, a crosslinker, and a catalyst to form the polyurethane coating composition.