1-Component Polysiloxane Anti-Slip / Non-Slip Coating

Abstract

A composition is disclosed that includes an organosilane polymer, a polyamide polymer, and an abrasive aggregate. The organosilane is made by reacting an amino-functional alkoxysilane with one or more polyisocyanates to form one or more adducts with unreacted isocyanate groups, and then reacting the adducts with one or more polyfunctional amino and / or hydroxyl compounds so that the polymer does not contain unreacted isocyanate groups. The polyfunctional amino and / or hydroxyl compounds have alicyclic or aromatic groups. The composition can be used to make a one-component polysiloxane anti-slip / non-slip coating that is applied by roller, spray, or trowel and cures with atmospheric moisture.

Description

Technical Field

[0001] The present disclosure generally relates to polysiloxane coatings.

Background Art

[0002] Anti-slip / non-slip coatings are viscous materials that provide an aggressive surface when applied with a roller, spray, or brush. These materials are used on the decks inside and outside of watercraft to provide traction for aircraft, crew, and equipment at sea. Similar materials are used to provide traction on the exteriors of aerospace ground support equipment, the floors of ground vehicles, and the blades of helicopters, although they have a lower profile of aggressiveness.

[0003] In naval watercraft, traditional anti-slip coatings are viscous two-component (2K) materials containing epoxy and amine functional molecules, pigments, solvents, fillers, thickeners, and abrasive aggregates. These components are mixed together using mechanical equipment and then applied to the decks of the ship via a lint-free phenolic roller or spray pump. Naval anti-slip coatings must meet MIL-PRF-24667 requirements and be present on decks where aviation operations occur. Unfortunately, epoxy-amine anti-slip coatings often fail to meet their required service life due to degradation by sunlight, which results in a decrease in wear profile and discoloration, delamination from the deck due to insufficient adhesion to the underlying primer, or topcoat damage that generates foreign object debris (FOD). Crew members often do not have the ability to apply additional anti-slip coatings because they cannot manually mix these viscous materials, and they apply primer to areas where the anti-slip coating has peeled off in order to prevent corrosion and further delamination. As a result, areas of the ship's deck often remain without a worn surface during deployment, and of course, the deck has an unsightly patchy appearance when covered in places with anti-slip and bare primer.

Summary of the Invention

[0004] Compositions comprising an organosilane polymer, a polyamide polymer, and an abrasive aggregate are disclosed herein. The organosilane polymer is made by a method comprising reacting an amino-functional alkoxysilane with one or more polyisocyanates to form one or more adducts having unreacted isocyanate groups, and reacting the adducts with one or more polyfunctional amino and / or hydroxyl compounds to form a polymer. The polyfunctional amino and / or hydroxyl compounds comprise an alicyclic group or an aromatic group. The organosilane polymer does not contain unreacted isocyanate groups.

[0005] A more complete understanding will be readily obtained by reference to the following detailed description of the invention and the accompanying drawings.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Detailed Description of the Invention

[0007] In the following description, specific details are set forth for the purpose of providing a thorough understanding of the present disclosure, but not by way of limitation. However, it will be apparent to those skilled in the art that the subject matter may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known methods and apparatus are omitted so as not to obscure the present disclosure with unnecessary detail.

[0008] Polysiloxane coatings containing silicon-oxygen bonds are becoming increasingly popular in the global coating market due to their superior outdoor durability, chemical resistance, and thermal stability compared to all organic polymer-based coatings. One-component (1K) polysiloxane anti-slip / non-slip coatings overcome the limitations of 2K epoxy-based coatings by providing a material that does not require metering and mixing of components, can be applied by roller or spray, and provides a wear surface with durability and color retention upon exposure to sunlight.

[0009] The one-component polysiloxane anti-slip / non-slip coatings described herein are based on synthetic organic silane polymers that contain alicyclic and / or aromatic units in the backbone and are terminated with alkoxysilane groups. These 1K anti-slip coatings also contain amide coating polymers and abrasive aggregates, in addition to fillers, pigments, solvents, additives, and catalysts. The coating can be applied onto the surface by roller, spray, brush, or trowel. Once applied, the alkoxysilane groups in the polymer hydrolyze with moisture to form silanols. These silanols then condense to form a hard polysiloxane / sol-gel network, providing a durable anti-slip / non-slip coating.

[0010] Organic silane polymers can be synthesized using various molecules, which must contain alicyclic or aromatic units in the backbone. These molecules include: 1) isocyanate-functional molecules such as aliphatic, alicyclic, and aromatic difunctional or trifunctional isocyanates; 2) amine-functional alkoxysilane molecules such as 3-aminopropyltrimethoxysilane, N-butyl-3-aminopropyltrimethoxysilane, and (N-cyclohexylmethyl)methyldiethoxysilane; 3) difunctional and trifunctional primary and secondary amines such as isophorone diisocyanate, 1,6-hexamethylenediamine, 4,4'-methylenebis(N-sec-butylcyclohexaneamine), metaxylylenediamine, and propane-1,2,3-triamine; and / or 4) hydroxyl-functional molecules such as 1,5-pentanediol, 4,4'-isopropylidenedicyclohexanol, 1,4-cyclohexanedimethanol, and dendritic polyester polyol.

[0011] Some suitable organic silane polymers are disclosed in U.S. Patent No. 10,190,020 (all publications and patent documents referred to throughout this application are hereby incorporated by reference). The organic silane polymer has terminal alkoxysilane groups formed by reacting an amine-functional alkoxysilane with a polyisocyanate to form an adduct. There are excess isocyanate groups relative to the amine groups, such that the adduct has unreacted isocyanate groups. The adduct is then reacted with a difunctional amino or hydroxyl compound to consume all of the unreacted isocyanate groups. A typical reaction scheme is shown below. Note that the use of a diol forms urethane groups in the polymer. Alternatively, a difunctional amino or hydroxyl compound can first be reacted with the isocyanate and subsequently with the amine-functional alkoxysilane to form the same compounds claimed herein. The claimed compounds can be made by either method. Each of the reactants may contain multiple compounds of such general structure. Other reactants may or may not be present. [Chemistry]

[0012] The value of a is 1, 2, or 3, and there is at least one alkoxy group bonded to the silicon atom. The value of n is a positive integer, and the polyisocyanate has n + 1 isocyanate groups. The organosilane polymer may be a mixture of the above compound and other organosilane polymers. The mixture may contain a small amount of polymer in which all isocyanate groups react with the amine-functional alkoxysilane, as shown below. [Chemistry]

[0013] The reaction can also produce a mixture of compounds depending on the ratio of the reactants. For example, when more than 50 mol% of the amine-functional alkoxysilane is used, a part of the polyisocyanate completely reacts with the amine-functional alkoxysilane as shown above. When more than 50 mol% of NH or OH from a bifunctional amino or hydroxyl compound is used, respectively, the reaction produces some compounds having a plurality of repeating units (m) of the bifunctional amino or hydroxyl compound, as shown below. [Chemistry]

[0014] The organosilane polymer has no unreacted isocyanate groups. As used herein, "having no unreacted isocyanate groups" means that sufficient isocyanate-reactive groups are used to react with all isocyanate groups, although a trace amount of unreacted isocyanate may remain.

[0015] Each R of the amine-functional alkoxysilane 1 group, all R 1It can be an alkyl group independently selected such that the groups are the same or can be of multiple types. Each R of the amine-functional alkoxysilane 2 group can independently be selected hydrogen, aryl, alkyl, cycloalkyl, ester-containing aliphatic, ester-containing fluorinated aliphatic, amide-containing aliphatic, or polysiloxane. The amine-functional alkoxysilane is a compound different from the organosilane polymer itself and may not contain urea groups and urethane groups. Suitable amine-functional alkoxysilanes include, but are not limited to, N-butyl-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, (N-cyclohexylmethyl)methyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, or N-[3-(trimethoxysilyl)propyl]-β-alanine butyl ester.

[0016] The R 3 groups of the polyisocyanate can be aliphatic, alicyclic, or aromatic. Aliphatic isocyanates can provide good flexibility and weather resistance by coating. Suitable polyisocyanates include, but are not limited to, hexamethylene diisocyanate, homopolymers of hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, homopolymers of isophorone diisocyanate, or methylene diphenyl diisocyanate, and mixtures thereof. Commercially available polymeric isocyanates may include mixtures such as dimers and trimers of hexamethylene diisocyanate.

[0017] Each R of the difunctional amino compound 4 group can independently be selected hydrogen, aryl, alkyl, cycloalkyl, ester-containing aliphatic, ester-containing fluorinated aliphatic, amide-containing aliphatic, or polysiloxane. Each R of the difunctional amino or hydroxyl compound 5The base includes an alicyclic group, or an aromatic group, or any combination thereof. Suitable difunctional amino or hydroxyl compounds include, but are not limited to, isophoronediamine, 1,6-hexamethylenediamine, 1,3,3-trimethyl-N-(1-methylethyl)-5-[(1-methylethyl)amino]cyclohexanemethanamine, 4,4'-methylenebis(N-sec-butylcyclohexanamine), propane-1,2,3-triamine, 1,5-pentanediol, 4,4'-isopropylidenedicyclohexanol, 1,4-cyclohexanedimethanol, or dendritic polyester polyol.

[0018] The alkoxysilane-terminated organic silane polymer may also be a specific polyurea disclosed in U.S. Patent Nos. 9,139,753 or 9,701,868, both of which are incorporated herein by reference and the specific subject matter of which is included below. The teachings of these applications may be applied to the presently disclosed polyureas.

[0019] The polyisocyanate can be aliphatic, alicyclic, or aromatic. Aliphatic polyisocyanates are more weather-resistant (i.e., have outdoor durability) than aromatic polyisocyanates, thereby providing higher color stability when used in exterior coatings. Depending on its structure, an aliphatic polyisocyanate can have a different number of reactive isocyanate (NCO) groups per molecule. Typically, the number ranges from 2.5 to 5.5. For the present coating composition, the aliphatic polyisocyanate can have more than two NCO groups per molecule. Suitable aliphatic polyisocyanates include, but are not limited to, isocyanurates (e.g., HDI and IPDI trimers), biurets, uretdiones, allophanates, oxadiazinetriones, iminooxadiazinediones, and structures based on urethane-containing prepolymers. Mixtures of these isocyanates can also be used. There are many commercially available aromatic, aliphatic, and alicyclic polyisocyanates.

[0020] The N-substituted amino-functional alkoxysilane can be an N-substituted 3-aminopropyltrialkoxysilane, an N-substituted 3-aminopropylalkyldialkoxysilane, or an N-substituted dialkylalkoxysilane. The alkyl group bonded to the silicon atom can be methyl or ethyl, and the alkoxy group bonded to the silicon atom can be methoxy, ethoxy, n-propoxy, or n-butoxy.

[0021] The N-substituent of the N-substituted amino-functional alkoxysilane is a C 1 ~C 12 alkyl, cycloalkyl, or aryl. Examples include, but are not limited to, N-methyl-3-aminopropyltrimethoxysilane, N-ethyl-3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltributoxysilane, N-ethyl-3-aminopropyltripropoxysilane, N-isopropyl-3-aminopropyltrimethoxysilane, N-tert-butyl-3-aminopropyltrimethoxysilane, N-butyl-3-aminopropyltrimethoxysilane, N-butyl-3-aminopropylmethyldimethoxysilane, N-butyl-3-aminopropyldimethylmethoxysilane, N-butyl-3-aminopropyltriethoxysilane, N-butyl-3-aminopropyltripropoxysilane, N-butyl-3-aminopropyltributoxysilane, N-isobutyl-3-aminopropyltrimethoxysilane, N-cyclohexyl-3-aminopropyltrimethoxysilane, N-hexyl-3-aminopropyltrimethoxysilane, N-nonyl-3-aminopropyltrimethoxysilane, and N-dodecyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane. Many of these are commercially available.

[0022] The N-substituent of the N-substituted amino-functional alkoxysilane may also be an ester-containing aliphatic or an ester-containing fluorinated aliphatic, which are formed by a Michael addition (conjugate addition) reaction between a molecule having a reactive "ene" group such as acrylate and 3-aminopropyltrialkoxysilane, 3-aminopropylalkyldialkoxysilane, or 3-aminopropyldialkylalkoxysilane. The formation conditions of the adduct by Michael addition with an amine are well known in the literature. Suitable acrylates include, but are not limited to, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, 4-tert-butylcyclohexyl acrylate, diethyl maleate, dimethyl maleate, dibutyl maleate, ethylene glycol methyl ether acrylate, 1,1,1,3,3,3-hexafluoroisopropyl acrylate, 2,2,2-trifluoroethyl acrylate, and 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl acrylate. Examples include, but are not limited to, methyl 3-((3-(trimethoxysilyl)propyl)amino)propanoate, butyl 3-((3-(trimethoxysilyl)propyl)amino)propanoate, 2-ethylhexyl 3-((3-(trimethoxysilyl)propyl)amino)propanoate, octyl 3-((3-(trimethoxysilyl)propyl)amino)propanoate, 3,3,3-trifluoropropyl 3-((3-(trimethoxysilyl)propyl)amino)propanoate, dimethyl (3-(trimethoxysilyl)propyl)aspartate, and diethyl (3-(trimethoxysilyl)propyl)aspartate.

[0023] The N-substituent of the N-substituted amino-functional alkoxysilane may also be amide-containing aliphatic, which is formed by a Michael addition (conjugate addition) reaction between a molecule having a reactive "ene" group such as acrylamide and 3-aminopropyltrialkoxysilane, 3-aminopropylalkyldialkoxysilane, or 3-aminopropyldialkylalkoxysilane. Suitable acrylamides include, but are not limited to, N-ethylacrylamide, N-propylacrylamide, N-tert-butylacrylamide, N-cyclohexylacrylamide, N-ethylmaleimide, and N,N'-diethylmaleamide. Examples include, but are not limited to, N-propyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide, N-butyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide, N-cyclohexyl-3-((3-(trimethoxysilyl)propyl)amino)propanamide, and 1-ethyl-3-((3-(trimethoxysilyl)propyl)amino)pyrrolidine-2,5-dione.

[0024] One of ordinary skill in the art will understand that a small amount of isocyanate groups (e.g., 1-5%) may remain unreacted in the polymer and thereby can be used to assist adhesion to the substrate or can be used to react with isocyanate-reactive materials not discussed herein. However, reacting a small percentage of the isocyanate groups on the polymer with materials not disclosed is not likely to change the properties of the polymer and should not be considered a separate polymer. To make an isocyanate-free coating, it is recommended to react all of the isocyanate groups during the synthesis of the organosilane polymer.

[0025] Solvents suitable for the synthesis of organic silane polymers are those that do not react with isocyanate groups. These solvents include, but are not limited to, xylene, light aromatic naphtha, mineral spirits, butyl acetate, 1-methoxy-2-propyl acetate, tert-butyl acetate, butyl propionate, pentyl propionate, ethyl 3-ethoxypropionate, 4-chlorobenzotrifluoride, tetrahydrofuran, 1,4-dioxane, dimethylacetamide, and N-methylpyrrolidone.

[0026] The catalyst can be used to accelerate the hydrolysis rate of the alkoxysilane group and to promote the crosslinking of the resulting silanol groups to form a cured coating. Suitable catalysts include, but are not limited to, organic tin compounds such as dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin bis(2-ethylhexanoate), metal alkoxides such as titanium tetraisopropoxide, aluminum triethoxide, zirconium tetrabutoxide, and titanium chelates containing aminoalkoxysilane, potassium hydroxide, organic acids, inorganic acids, tertiary amines, or mixtures thereof.

[0027] Suitable pigments include, but are not limited to, titanium dioxide, carbon black, iron oxide red, iron oxide yellow, copper phthalocyanine blue, sodium aluminosilicate sulfonate, chromium oxide, cobalt chromite green spinel, chromium green black hematite, nickel antimony titanium yellow orpiment, and manganese-based pigments.

[0028] The polyamide polymer may be used to provide flexibility or thixotropy and may be any polymer containing amide groups in the polymer backbone, which may be an aliphatic, alicyclic, or aromatic polyamide. Examples include, but are not limited to, fatty acid-based polyamides, dimerized fatty acid-based polyamides, paraphenylene terephthalamide, nylon, polyaspartate, and poly(hexamethylene adipamide).

[0029] A filler can be any material used to fill the volume of a composition, adjust its viscosity, or improve its corrosion resistance. Examples include, but are not limited to, talc, ceramic microspheres, amorphous silica, hollow glass spheres, mica, aluminum flakes, aluminum spheres, zinc particles, glass flakes, wollastonite, and calcium carbonate.

[0030] An additive can be any material contained in small amounts to adjust the viscosity, impact resistance, weather resistance, or other properties of a composition. These additives include, but are not limited to, pigment dispersants, rubber beads, polyethylene fibers, polypropylene fibers, hindered amine light stabilizers (HALS), ultraviolet absorbers (UVA), conductive polyaniline, and graphene.

[0031] An abrasive aggregate can be any particles incorporated into a composition that increase the coefficient of friction of the surface of the composition when it solidifies. It can be rounded or angular particles having a size of 0.10 to 2.5 mm and a Mohs hardness of 3 to 9. Examples include, but are not limited to, brown aluminum oxide, white aluminum oxide, walnut shell, aluminum, crushed glass, glass beads, corn cob, melamine, acrylic, and urea.

[0032] When the composition is applied to a surface, it can cure to form a solid coating. The alkoxysilane groups of the organosilane polymer undergo hydrolysis and condensation with each other.

[0033] Unlike two-component anti-slip coatings, one-component polysiloxane anti-slip is an all-in-one can system that does not require weighing and mixing of components. The anti-slip can be easy to stir and apply, and furthermore, provides an aggressive and hard profile when cured. The silicon-oxygen bonds in the coating provide higher resistance to degradation by sunlight than polymers based entirely on organic bonds, such as those used in epoxy-amine anti-slips. Thus, the 1K anti-slip can retain its color and profile for a longer period. The 1K anti-slip that provides enhanced outdoor durability can extend the service life of anti-slip on ship decks and reduce maintenance costs.

[0034] The following examples are given to illustrate specific applications. These specific examples are not intended to limit the scope of the disclosure of this application.

[0035] Example 1 Synthesis of an organosilane polymer - An aliphatic isocyanate based on hexamethylene diisocyanate uretdione (Desmodur N-3400, Covestro) is dissolved in 4-chlorobenzotrifluoride (Sigma-Aldrich) (~1.2 / 1 by weight of isocyanate / solvent) in a 1 L four-neck round bottom flask equipped with a nitrogen inlet, mechanical stirrer, and thermometer. Next, vinyltrimethoxysilane (Gelest) is added as a moisture scavenger. Using a dropping funnel, N-butyl-3-aminopropyltrimethoxysilane (Gelest) (ratio of equivalent NH to equivalent NCO 3 / 5) is added dropwise to the solution while maintaining the temperature at 50 - 60 °C. Once the addition is complete, 1,3,3-trimethyl-1-aminomethyl-5-aminocyclohexane (Clearlink 1080, Dorf Ketal), an aliphatic cyclic diamine (ratio of equivalent NH to equivalent NCO 2 / 5), is added dropwise while maintaining the temperature at 50 - 60 °C again. After the addition, the reaction is stirred for an additional 30 minutes to 1 hour until all isocyanate groups are consumed, according to FTIR analysis. The structure of one polymer made from the reaction is shown in Figure 1.

[0036] Example 2 1-Component Anti-Slip / Non-Slip Formulation - A 1-component anti-slip / non-slip coating is prepared by mixing the organosilane polymer from Example 1 with titanium dioxide (R-960, Chemours), inorganic black pigment (Black 30C940, Shepherd Pigments), inorganic blue pigment (Blue 30C527, Shepherd Pigments), and ceramic microspheres (W-610, 3M). Subsequently, an amide-containing polymer (Crayvallac PA4BA20, Palmer Holland), fibrillated high-density polyethylene fibers (Mini Fibers, Inc.), 12 - 30 mesh glass beads (Blast-O-Lite), and dibutyltin dilaurate (Sigma-Aldrich) are added. The range of proportions in the formulation is shown in Table 1. After mixing, the coating is applied onto an epoxy primed steel sheet using a 9-inch napless phenolic roller (Grainger) and then cured at 72°F and 40 - 60% relative humidity for 14 days. Figure 2 shows the structure of one cross-linked (cured) organosilane polymer made from the reaction. Figure 3 shows an example of the anti-slip / non-slip coating applied with a roller after overnight curing. The polysiloxane coating is hard to the touch after 1 day.

[0037] The amount of organosilane polymer used depends on the application. For example, a non-slip formulation for stairs uses a high proportion of polymer, as well as a low proportion of aggregates and fillers. A high-friction anti-slip surface for driveways uses a lower proportion of polymer, as well as a higher proportion of aggregates and fillers.

Table 1

[0038] Obviously, many modifications and variations are possible in light of the above teachings. Accordingly, it should be understood that the claimed subject matter may be practiced in ways other than as specifically described. For example, references to singular claim elements using the articles "a", "an", "the", or "said" are not to be construed as limiting the element to the singular form.

Claims

Claim 1 An organosilane polymer comprising: reacting an amino-functional alkoxysilane with one or more polyisocyanates to form one or more adducts having unreacted isocyanate groups; and reacting the adducts with one or more polyfunctional amino and / or hydroxyl compounds such that the polymer does not contain unreacted isocyanate groups, wherein the polyfunctional amino and / or hydroxyl compounds contain an alicyclic group or an aromatic group and are selected from the group consisting of isophoronediamine, m-xylylenediamine, 4,4'-methylenebis(N-sec-butylcyclohexaneamine), 4,4'-isopropylidenedicyclohexanol, 1,4-cyclohexanedimethanol, and dendritic polyester polyols containing an alicyclic group or an aromatic group an organosilane polymer produced by a method comprising; a polyamide polymer; and abrasive aggregate a composition comprising. Claim 2 The composition according to claim 1, wherein the amino-functional alkoxysilane is N-butyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, or (N-cyclohexylmethyl)methyldiethoxysilane. Claim 3 The composition according to claim 1, wherein the polyisocyanate is hexamethylene diisocyanate, a homopolymer of hexamethylene diisocyanate, toluene diisocyanate, isophorone diisocyanate, a homopolymer of isophorone diisocyanate, or methylene diphenyl diisocyanate. Claim 4 The composition according to claim 1, wherein the polyamide polymer contains an aliphatic group, an aromatic group, or both. Claim 5 The composition according to claim 1, wherein the abrasive aggregate is rounded or angular particles. Claim 6 The abrasive aggregate is particles having an average diameter of 0.10 to 2.5 mm, and the abrasive aggregate has an average Mohs hardness of 3 to 9. The composition according to claim 1. Claim 7 The composition according to claim 1, further comprising a solvent, a pigment, a filler, an additive, or a catalyst. Claim 8 A method comprising applying the composition according to claim 1 onto a surface and curing the composition by reaction of the alkoxysilane groups with moisture in the air and subsequent condensation of the silanol groups. Claim 9 Claim 10 ​ ​ One-component polysiloxane anti-slip / non-slip coating produced by the method according to claim 8.

10. The one-component polysiloxane anti-slip / non-slip coating according to claim 9, wherein the composition is applied by a roller, a spray, or a trowel.

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