Method for applying an antimicrobial coating to a substrate.

Abstract

To provide textured printed antibacterial or antimicrobial coatings.SOLUTION: An antimicrobial coating composition includes at least one cured phase change ink which may include one or more crosslinked polymers, a photoinitiator, a wax, a gellant, and an antimicrobial additive. The composition also includes an engineered surface topography formed by the cured phase change ink. A method of preparing a textured antimicrobial surface is also disclosed. The method may include designing a template having a texture, printing the template onto a substrate using an uncured antimicrobial ink, and providing a light source to crosslink the uncured antimicrobial ink.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to printed antibacterial or antimicrobial coatings, and more specifically to textured printed antibacterial or antimicrobial coatings.

Background Art

[0002] The adhesion of bacteria and biofilms to material surfaces is greatly influenced by the surface's topography and roughness. Bacterial adhesion to surfaces can be influenced by many factors, including hydrophobicity, van der Waals forces, electrostatic interactions, and steric hindrance. All naturally occurring surfaces, such as shark skin, lotus leaves, and dragonfly wings, exhibit some kind of bactericidal or antimicrobial properties depending on some of these factors. For example, dragonfly wings exhibit nanoscale pillar structures that inhibit the growth of several bacterial strains, while lotus leaves possess both nanoscale and microscale hierarchical structures that promote superhydrophobicity and self-cleaning properties. Shark skin patterns have a diamond-like riblet appearance, which is perfectly designed for reduced resistance and self-cleaning. Through the discovery and study of these naturally occurring surfaces and properties, many researchers are exploring biomimetic approaches to help inhibit bacterial contamination on animate surfaces, including frequently touched surfaces such as doorknobs, bed or stair railings, touchscreen monitors, and mobile phones. Currently, with the rise of infectious diseases and the prevalence of antibiotic resistance, new coatings for these frequently touched surfaces are highly advantageous, especially in healthcare-related environments such as hospitals, medical clinics, or dental offices. Furthermore, there are ongoing problems with bacterial and fungal contamination through contact with surfaces and objects on airplanes and cruise ships. For example, an individual suffering from gastroenteritis can easily spread the disease by touching handrails, shared equipment, elevator buttons, etc. In some cases, contamination can be particularly fatal, such as gastroenteritis caused by norovirus on a cruise ship, or food poisoning outbreaks caused by specific strains of E. coli and Salmonella. Another bacterium, Staphylococcus aureus, is a major cause of many diseases and skin irritations. There are also methicillin-resistant strains of Staphylococcus aureus (known as MRSA) that are resistant to the antibiotic methicillin and other drugs of this type.

[0003] An example of a biomimetic antimicrobial coating can be found in commercially available products that provide a uniform width of micropatterns with diamond patterns protruding and recessed on the material surface to enhance antimicrobial properties. These microstructures are fabricated in silicon by using photolithography, where silicon wafer molds can be replicated with hierarchical design and engineered roughness indices. These patterned surfaces are repeated throughout the coating and then attached to the surface. It should be noted that the use of several commercially available micropatterned surfaces resulted in up to a 55% reduction in Gram-negative bacteria (Escherichia coli) and a 76% reduction in colony size compared to a smooth film after a 24-hour incubation period. This study and others have found that patterned surfaces lead to bacterial accumulation on the surface after a sufficient amount of time. Microtopography alone does not reduce contamination and bacterial accumulation.

[0004] Additional techniques for replicating naturally occurring surfaces include lithography methods such as electron beam, X-ray, and nanoimprint lithography. As mentioned earlier, lithography involves replicating a surface pattern from a master and transferring it to another surface. Some of these lithography techniques can be time-consuming and expensive when the fabrication of large nanostructures is required to cover large areas such as walls and desks. Other fabrication methods can use vacuum casting, which may be limited to microscale structures or femtosecond lasers, and is a promising method used for orthopedic implants where micro and nanostructured surface patterns can be fabricated directly onto titanium substrates. Conventional coating techniques also require adhesive backing to bond the film to the surface, and custom measurements, cutting operations, and the application of coatings or films to inanimate surfaces are also costly.

[0005] Therefore, there is a need for multifunctional coatings that can be formulated with antimicrobial agents such as silver nanoparticles to enhance the effectiveness of the coating. The ability to digitally modify various patterns across the entire coated surface, changing pitch, height, width, and other parameters in-line as needed, would offer advantages and faster turnaround times unattainable with photolithography. The ability to directly print various patterns or areas of different patterns onto inanimate surfaces, rather than fabricating pre-patterned adhesive coatings, would also result in cost savings and other benefits. Furthermore, the ability to print stamp molds as needed, instead of using conventional fabrication methods, would also significantly reduce time and cost, as digital planning and printing of molds is faster than mixing, injecting, oven curing, and peeling soft molds from master molds to obtain the necessary inverse structure for imprinting microtopographic patterns. [Overview of the Initiative]

[0006] The following is a simplified overview to provide a basic understanding of some aspects of one or more embodiments of this teaching. This overview is not a broad summary and is not intended to identify the main or important elements of this teaching or to specify the scope of this disclosure. Rather, its primary purpose is simply to present one or more concepts in a simplified form as a prelude to the detailed explanations that will be presented later.

[0007] An antimicrobial composition is disclosed. The antimicrobial coating composition comprises at least one cured phase change ink, which may include one or more crosslinked polymers, a photoinitiator, a wax, a gelling agent, and an antimicrobial additive. The composition also comprises an engineered surface topography formed by the cured phase change ink.

[0008] A specific implementation may include an antimicrobial coating composition in which one or more acrylate monomers are present in an amount of about 4.0% to about 80.0% based on the total weight of the antimicrobial coating composition. These one or more acrylate monomers may include difunctional acrylate monomers, trifunctional acrylate monomers, tetrafunctional acrylate monomers, and pentafunctional acrylate monomers, or combinations thereof. The antimicrobial coating composition may further include pentafunctional acrylate monomers and difunctional acrylate monomers. Wax may be present in an amount ranging from about 2.5% to about 15% based on the total weight of the antimicrobial coating composition. Crosslinkable acrylate waxes are further examples of waxes. A gelling agent may be present in an amount ranging from about 2.5% to about 15.0% based on the total weight of the antimicrobial coating composition. Radiation-curable gelling agents may be examples of radiation-curable gelling agents. Amide gelling agents may further be examples of radiation-curable gelling agents. Antimicrobial additives may be present in an amount ranging from about 0.01% to about 5.00% based on the total weight of the antimicrobial coating composition. Examples of antimicrobial additives include metal nanoparticles, ionic polymer-metal composite nanoparticles, quaternary ammonium compounds, n-haramine molecules, biguanides, metal oxides, or combinations thereof. Silver nanoparticles may also be an example of an antimicrobial additive. Specific embodiments of the antimicrobial composition may include an engineered surface topography having an engineered roughness index (ERI) of about 5 to about 50. The engineered surface topography may include protruding shapes spaced about 1 to about 5000 nm apart, having a height of about 10 to about 5000 nm, or having an actual surface area to geometric surface area ratio of about 2 to about 40.

[0009] A method for preparing a textured antimicrobial surface is disclosed. This method may include designing a template having a texture, printing the template onto a substrate using an uncured antimicrobial ink, and providing a light source for crosslinking the uncured antimicrobial ink. [Brief explanation of the drawing]

[0010] The accompanying drawings incorporated herein and constituting part of this specification illustrate embodiments of this teaching and, together with the description, serve to illustrate the principles of this teaching.

[0011] [Figure 1] This is a schematic diagram illustrating a process for applying an antimicrobial ink to a substrate using a transfer roll process according to an embodiment.

[0012] [Figure 2A] These are several flowcharts illustrating alternative methods for creating printed and textured surfaces with antimicrobial properties, according to embodiments. [Figure 2B] These are several flowcharts illustrating alternative methods for creating printed and textured surfaces with antimicrobial properties, according to embodiments. [Figure 2C] These are several flowcharts illustrating alternative methods for creating printed and textured surfaces with antimicrobial properties, according to embodiments.

[0013] Please note that some details in the figures have been simplified and are shown to facilitate understanding of the embodiments, rather than maintaining strict structural accuracy, detail, and scale. [Modes for carrying out the invention]

[0014] Hereinafter, embodiments of the present disclosure will be referenced in detail. The following description is for illustrative purposes only.

[0015] The following description refers to the accompanying drawings illustrating specific exemplary embodiments that form part of this teaching and enable its implementation. These embodiments are described in sufficient detail to enable those skilled in the art to carry out this teaching, and it will be understood that other embodiments may be available and that modifications may be made without departing from the scope of this teaching. Therefore, the following description is merely illustrative.

[0016] The embodiments disclosed herein are not limited in this respect, but as used herein, the terms “plurality” and “a plurality” may include, for example, “multiple” or “two or more.” The terms “plurality” or “a plurality” may be used throughout this specification to describe two or more components, devices, elements, units, parameters, etc. For example, “multiple resistors” may include two or more resistors.

[0017] When used herein, the modifier “about” in relation to quantity includes the stated value and has a meaning determined by the context (for example, it includes at least the degree of error relating to the measurement of a particular quantity). In embodiments, the term of interest includes variation of less than about 10% from the stated value. When used in the context of a range, the modifier “about” should also be considered to disclose a range defined by the absolute values ​​of two endpoints. For example, the range “about 2 to about 4” also discloses the range “2 to 4”.

[0018] As used herein, “metal acrylates,” such as “silver acrylate,” are aggregates of acrylate monomers containing at least one metal atom, such as a silver atom, used in polymers, for example, silver acrylate and silver methacrylate monomers for silver-containing polymers.

[0019] As used herein, the term “antibacterial” refers to the properties of a composition for inhibiting or destroying the growth of bacteria. In other words, an ink or ink component having antibacterial properties is effective in killing bacteria or inhibiting the growth or proliferation of bacteria contained in a printed image or structure.

[0020] As used herein, the term “antibiotic” refers to an agent or property conferred by an agent that kills or inhibits the growth of microorganisms or microbes. An antibacterial agent or its properties is an antimicrobial agent. Examples of microorganisms include bacteria, fungi, algae, other single-celled organisms, protists, nematodes, parasites, other multicellular organisms, and other pathogens. In other words, an ink or ink component containing antimicrobial properties is effective in killing microorganisms or inhibiting the growth and proliferation of microorganisms contained in a printed image or structure.

[0021] When used in the context of "silver nanoparticles," the term "nano" refers to a particle size less than approximately 1000 nanometers (nm). In embodiments, silver nanoparticles have particle sizes of approximately 0.5 nm to approximately 1000 nm, approximately 1 nm to approximately 500 nm, approximately 1 nm to approximately 100 nm, and approximately 1 nm to approximately 20 nm. Particle size is defined herein as the average diameter of the silver nanoparticles, as determined by TEM (transmission electron microscopy). In embodiments, composite nanoparticles have a volume-average particle diameter (D50) of approximately 10 to approximately 600 nanometers, or approximately 10 to approximately 300 nanometers, or approximately 10 to approximately 200 nanometers.

[0022] A polymer may be identified or named herein by the two or more constituent monomers used to make up the polymer, even if, after polymerization, the monomers change and are no longer identical to the original reactants. For example, polyesters often consist of polyacid monomers or components and polyalcohol monomers or components. Therefore, when trimellitic acid reactants are used to produce a polyester polymer, the resulting polyester polymer may be identified herein as trimellitic polyester. Alternatively, a polymer may consist of styrene monomers and acrylate monomers, in which case, after polymerization, it may be identified based on the monomers used. For example, when the acrylate is butyl acrylate, the resulting polymer may be referred to as a styrene polymer, butyl acrylate polymer, styrene / acrylate polymer, etc.

[0023] The term "two-dimensional" such as 2-D or its grammatical forms means related to a structure or surface that has no substantially measurable or distinguishable depth without using a mechanical measuring device. Generally, the surface is identified as flat, emphasizing height and width and lacking the illusion of depth or thickness. Thus, for example, toner is applied to the surface to form an image or coating, and generally, the layer of molten toner is about 1 micrometer (μm) to about 10 μm thick. Nevertheless, the application of toner to a flat surface is considered a two-dimensional application herein. The surface can be, for example, a sheet or paper. This definition does not mean a mathematical or scientific definition at the molecular level, but is for the viewer or observer's eye and there is no illusion of thickness. Thicker layers of toner, such as those that can be identified as providing "raised lettering" on the surface, are included in the 2-D definition for the purposes of this specification.

[0024] The term "three-dimensional" such as 3-D or its grammatical forms means related to a structure consisting of multiple layers of toner or particle deposits that are assembled or grouped together to result in a form, shape, construct, object, etc. that does not necessarily need to be applied to a surface or structure, can be autonomous, and / or has thickness or depth. Printing as used herein includes generating a 3-D structure. Printing on a surface or structure is also used and includes forming a 3-D structure by the deposition of multiple layers of toner herein. In many cases, the first layer is printed on a support, surface, substrate, or structure. Successive layers of toner are placed thereon and the already deposited (and optionally adhered or solidified) toner layer or layers are considered a surface or substrate herein.

[0025] The terms "substrate", "media substrate", "printing substrate", and "printing medium" generally refer to a physical sheet, usually flexible, such as paper for images, polymers, Mylar® materials, plastics, or other suitable physical printing media substrates, fabrics, sheets, webs, etc., regardless of precut or web supply.

[0026] As used herein, the terms “printing device” or “printing system” refer to any device useful for performing a printing process, such as a digital copier or printer, scanner, image printer, electrophotographer, electrostatic camera, digital production press, document processing system, image player, bookbinding machine, facsimile machine, multifunction device, or generally any device useful for performing a printing process, and may include several marking engines, feeding mechanisms, scanning assemblies, and other printing media processing units such as paper feeders and finishers. A “printing device” is capable of printing on a surface in a manner that may be raised above the upper surface of the substrate, and is further described as two-dimensional (2D), 2.5-dimensional (2.5D), or three-dimensional (3D), resulting in a textured, structured, or raised printed surface as printed by a “printing device.” A “printing system” can handle sheets, webs, substrates, etc. A printing system is any machine, or any combination of such machines, that can place marks on any surface and read marks on an input sheet.

[0027] All physical properties defined below are measured at 20°C to 25°C unless otherwise specified. The term "room temperature" refers to a temperature range of approximately 20°C to 25°C, such as approximately 22°C, unless otherwise specified.

[0028] An antimicrobial composition is provided, comprising an antimicrobial ink, comprising a radiation-curable or crosslinkable acrylate monomer, a photoinitiator, a wax, a gelling agent, an optional colorant, an optional UV stabilizer, and an antimicrobial additive. The antimicrobial coating further comprises a textured surface or an engineered surface topography, the surface comprising protruding shapes spaced about 1 to about 1000 nm apart, and a roughness index of about 5 to about 50. The engineered surface topography may comprise protruding shapes having a height of about 10 to about 500 nm. The engineered surface topography may have a ratio of actual surface area to geometric surface area of ​​about X to about Y. The engineered surface topography or textured surface may enhance the microbial resistance of the antimicrobial coating composition through a combination of effects with the coating composition, which may include the addition of antimicrobial agents such as silver nanoparticles to enhance the antimicrobial efficacy of such coatings.

[0029] In certain embodiments, a textured antimicrobial surface may be provided by one or more methods, including preparing the textured antimicrobial surface by designing a template including a texture, printing a negative of the template onto a stamping substrate, stamping the stamping substrate onto a printed surface using uncured antimicrobial ink, and providing a light source for crosslinking the uncured antimicrobial ink. Embodiments for providing a textured antimicrobial surface may include designing a template including a texture, printing the template onto a substrate using uncured antimicrobial ink, and providing a light source for crosslinking the uncured antimicrobial ink. Further embodiments for providing a textured antimicrobial surface having an engineered surface topography may include applying uncured antimicrobial ink to a textured roll, transferring the uncured antimicrobial ink from the textured roll to a substrate, and providing a light source for crosslinking the uncured antimicrobial ink.

[0030] The antimicrobial phase-change ink compositions and methods described herein may be applied to indirect printing applications using an inkjet print head, in which the ink is first image-likely applied onto an intermediate receiving member such as a drum or belt. The ink wets and spreads on the intermediate receiving member, forming a transient image. The transient image then undergoes a change in properties, such as partial or complete drying, thermal curing or photocuring, or gelation, and the resulting transient image is then transferred to a final image-receiving substrate. The inks may be designed and optimized to suit different subsystems, including spraying and transfer, enabling high-speed, high-quality printing. The antibacterial or antimicrobial phase-change ink compositions described herein may also be applied to direct printing applications.

[0031] Inkjet printing is one of the fastest-growing image formation technologies. Some of the advantages of inkjet printing compared to other printing methods include simplification, lower production costs, reduced effluent waste, and lower water and energy consumption. Based on the increasing need for high-performance products, particularly in areas related to health and hygiene, current water-based digital printing inks with antibacterial properties meet market needs, providing consumers with robust, effective, and lasting antimicrobial protection on any printable surface. Some key environments that can benefit from printing using this antimicrobial phase-change ink composition include hospitals, daycare centers, nursing homes, schools, dental clinics, hospitals (e.g., charts, memos, photographs), other types of medical institutions, veterinary hospitals, law firms and courts (e.g., legal documents), kitchens, and restaurants (e.g., menus). This antimicrobial ink, along with the images or engineered surfaces printed with it, helps maintain a fresh appearance by making any product more hygienic and completely reducing or avoiding odor-causing or stain-causing microorganisms, and also prevents important identification tags, labels, or drug identification numbers (DINs) from being degraded by microorganisms. In embodiments, the antimicrobial ink composition comprises silver composite nanoparticles. Silver exhibits antimicrobial activity against a wide range of microorganisms. Silver is considered an ideal antimicrobial agent because it is highly effective against a wide range of relevant microorganisms and is considered non-toxic, especially considering the low concentrations required for effective decontamination.

[0032] In the embodiments described herein, indirect or direct printing of ridged, textured patterns combined with antimicrobial additives offers the advantage of combining surface topography engineered to inhibit microbial adhesion with the bactericidal effect of antimicrobial or antibacterial additives. These textured micropatterns can be digitally printed directly onto surfaces with various deposition patterns, or onto stamp masks or rollers, when high throughput and large-area patterning are required. These methods, which may utilize UV-curable phase-change inks for printing the textured patterns, are a cost-effective way to rapidly and directly print various surface topography onto articles, instead of fabricating new silicon wafer molds or polydimethylsiloxane (PDMS) stamps each time a new micropattern is needed or an antimicrobial effect needs to be evaluated.

[0033] The antimicrobial phase-change inks and topographic engineering design methods described herein can be used for any suitable or desired application. The inks are particularly suitable for antimicrobial printing applications with the ultimate goal of producing customizable, digitized antimicrobial printed images, text, surface coatings, etc. Examples of applications include printing codes, labels, or logos on medical devices such as catheters, thermometers, and other medical devices, as well as printing on menus, food packaging materials, cosmetic tools, and products.

[0034] In certain embodiments, the antimicrobial phase-changing ink and topographic engineering design method may enable surfaces or objects to be kept clean from microorganisms by directly printing or adhering a printed and textured film having antimicrobial properties onto a frequently touched surface. While hospitals and medical clinics are some areas that require an additional layer of antimicrobial protection, these coatings can be applied to any high-traffic areas and objects such as handles, buses, trains, and airport public seats, check-in kiosks, toilets, counters, pushcarts / trolleys, elevator buttons, and elevator handrails. Medical implant surfaces are another problem of persistent microbial contamination, namely, the proliferation of microorganisms at the interface between implants and tissues, which is a common problem in perioperative (in-surgery) and postoperative patients, leading to deadly biofilm-related infections. Other applications include printing on digitally printed ID codes, short-term printable materials, catheters, cardiac stents, programmable pacemakers, and any other desired three-dimensional substrates.

[0035] The source of microorganisms may be bacteria, viruses, or fungi. Microbial contamination may result from typical handling of objects and paper, airborne microorganisms transmitted through sneezing and coughing, and transmission from contaminated individuals or other forms of contact with contaminated objects. Contact between these microorganisms and the antimicrobial phase-altering ink composition, including contact with printed images or text prepared using the antimicrobial phase-altering ink composition, inhibits microbial growth and, in embodiments, destroys any possible colonization at the contact site.

[0036] While changes or structuring of the micro / nanotopography of surface structures may play a significant role in the degree of microbial adhesion to the structure, surface roughness or topography alone may not prevent bacterial adhesion, as some bacterial cells can thrive on surfaces of a certain degree of roughness depending on their shape. Bacterial adhesion to surfaces may vary based on the rigidity of their membranes and their ability to stretch their cell membranes to conform to the surface. Spherical cells have been found to be less easily deformed and adhere more effectively to smooth surfaces than rod-shaped bacteria, which prefer rougher surfaces for adhesion.

[0037] Beyond topographic roughness, additional surface properties that may be involved in microbial adhesion include substrate chemistry, smoothness and particle size, nanopatterning or nanostructure, surface free energy, degree of hydrophobicity, surface charge, shape, multi-order structuring, and scaling. There are well-known examples of antibacterial surfaces found in nature. These natural surfaces differ topographically, including microstructure and nanostructure shapes, are self-cleaning, possess built-in antifouling properties, and exhibit superhydrophobicity. Examples of natural surfaces exhibiting many combinations of the properties described include insect wings such as those of dragonflies and cicadas, gecko feet, shark skin, and plant leaves, the most common of which is the lotus leaf.

[0038] Furthermore, it is known that some insects possess the ability to kill microorganisms through the physical means of sharp surface nanostructures that can cause bacterial cell walls to rupture or deform, leading to bacterial death. These sharp nanostructures are typically nanopillar-shaped, with diameters of 50–250 nm, heights of 80–250 nm, and pitches of 100–250 nm. Early studies of naturally occurring surfaces focused on surface wetting and antifouling properties that prevent bacterial growth on surfaces. These naturally occurring bactericidal mechanisms involve not only wetting and adhesion, but also the arrangement, height, pitch, and diameter of nanopillars that result in the physical and mechanical destruction of microorganisms. Several examples of naturally occurring bacterial surfaces are also known that can be mimicked via printing techniques to provide antibacterial protection on various surfaces and objects. Depending on the surface dimensions and other topographic shapes, the effectiveness of bacteria on a surface can be directed towards specific types or classes of bacteria. By combining such surface topography designs with antimicrobial agents such as silver nanoparticles or quaternary ammonium compounds (QACs), as well as other elements described later, long-lived contact-based antibacterial surfaces can be efficiently designed to provide sufficiently effective and long-lasting antimicrobial activity. Phase change ink

[0039] In embodiments, radiation-curable phase-change ink compositions used as materials for producing structured or textured surfaces having engineering-designed surface topography or three-dimensional objects may have a room-temperature modulus of about 0.01 to about 5 GPa. These inks may comprise radiation-curable monomers, photoinitiators, waxes, and gelling agents. Pigments, colorants, or other functional additives may be optionally included depending on the desired application. In further embodiments, a method for producing a textured surface having engineering-designed surface topography using such radiation-curable phase-change inks is disclosed. Radiation-curable phase-change inks as described herein may also be referred to as UV-curable phase-change ink compositions or antimicrobial phase-change ink compositions.

[0040] As referred to in this disclosure, the room temperature modulus value refers to the room temperature modulus value of the ink composition after the composition has been polymerized and cured. Furthermore, monomer refers to a monomer that is reactive and curable. monomer

[0041] As described above, the ink composition may contain monomers. Suitable monomers include radiation-curable monomer compounds such as acrylate and methacrylate monomer compounds, which are suitable for use as phase-change ink carriers. Examples of monomers include propoxylated neopentyl glycol diacrylate (such as Sartomer's SR-9003), diethylene glycol diacrylate, triethylene glycol diacrylate, hexanediol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, alkoxylated neopentyl glycol diacrylate, isodecyl acrylate, tridecyl acrylate, isobornyl acrylate, isobornyl (meth)acrylate, propoxylated trimethylolpropane triacrylate, ethoxylated trimethylol Examples include rolpropane triacrylate, di-trimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated glycerol triacrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, neopentyl glycol propoxylate methyl ether monoacrylate, isodecyl methacrylate, caprolactone acrylate, 2-phenoxyethyl acrylate, isooctyl acrylate, isooctyl methacrylate, and mixtures thereof. Relatively nonpolar monomers that can be mentioned include isodecyl (meth)acrylate, caprolactone acrylate, 2-phenoxyethyl acrylate, isooctyl (meth)acrylate, and butyl acrylate. In addition, polyfunctional acrylate monomers / oligomers, such as difunctional, trifunctional, tetrafunctional, and pentafunctional acrylate monomers, can be used not only as reactive diluents but also as materials that can increase the crosslinking density of the cured image, thereby enhancing the toughness of the cured image.

[0042] In embodiments, monomers may be selected from the group consisting of acrylic monomers, polybutadienes added with maleic anhydride, aliphatic urethane acrylates, polyester acrylates, 3-acrylooxypropyltrimethoxysilanes, and acrylooxypropyl t-structured siloxanes, or mixtures thereof. Other exemplary monomers include any monomers listed in Sartomer's product list under "Monofunctional Monomers" (http: / / www.sartomer.com / ).

[0043] In some embodiments, the composition may contain monomers in an amount of about 15 to about 80% by weight of the composition, such as about 20 to about 55% by weight or about 25 to about 50% by weight. In other embodiments, the composition may contain monomers in an amount of about 15 to about 35% by weight of the composition, or about 40 to about 60% by weight of the composition.

[0044] In embodiments, the above monomers can impart a room-temperature modulus of about 0.01 to about 5 GPa to the cured ink, such as about 0.51 to about 4.5 GPa, about 1.01 to about 4 GPa, about 1.51 to about 3.5 GPa, or about 2.01 to about 3 GPa. The room-temperature modulus may also be about 0.01 to about 1.7 GPa, about 1.7 to about 3.4 GPa, or about 3.4 to about 5 GPa.

[0045] In embodiments, a phase-change ink set may comprise different ink compositions, each imparting a different range of room temperature modulus. In embodiments, a phase-change ink set may comprise a first ink composition and at least one other ink composition, each having a different room temperature modulus between about 0.01 and about 5 GPa. For example, a phase-change ink set may comprise a first ink composition having a room temperature modulus of about 0.01 to about 2.5 GPa, such as about 0.01 to about 1.25 or about 1.25 to about 2.5 GPa, and a second ink composition having a room temperature modulus of about 2.5 to about 5 GPa, such as about 2.5 to about 3.75 GPa or about 3.75 to about 5 GPa.

[0046] The phase-change ink set may include a first ink composition having a room-temperature modulus of about 0.01 to about 1.7 GPa, such as about 0.01 to about 0.9 or about 0.9 to about 1.7; a second ink composition having a room-temperature modulus of about 1.7 to about 3.4 GPa, such as about 1.7 to about 2.6 GPa or 2.6 to about 3.4 GPa; and a third ink composition having a room-temperature modulus of about 3.4 to about 5 GPa, such as about 3.4 to about 4.3 or about 4.3 to about 5 GPa.

[0047] In this embodiment, the phase-change ink set may include 2 to 10 different ink compositions, such as 3 to 8, 4 to 6, 2 to 4, or 5 to 9 different ink compositions.

[0048] In embodiments, polyfunctional acrylate and methacrylate monomers and oligomers may be included in the phase-change ink carrier as reactive diluents and as materials that can increase the crosslinking density of the cured image and thereby enhance the toughness of the cured image. Different monomers and oligomers may be added to adjust the plasticity or elasticity of the cured object. Examples of suitable polyfunctional acrylate and methacrylate monomers and oligomers include pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, 1,2-ethylene glycol diacrylate, 1,2-ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate (available from Sartomer as SR238), 1,6-hexanediol dimethacrylate, 1,12-dodecanol diacrylate, 1,12-dodecanol dimethacrylate, tris(2-hydroxyethyl) isocyanurate triacrylate, propoxylated neopentyl glycol diacrylate (available from Sartomer as SR238). (Available as 9003), neopentyl glycol diacrylate (available from Sartomer as SR247), 1,4-butanediol diacrylate (BDDA, available from Sartomer as SR213), tripropylene glycol diacrylate, dipropylene glycol diacrylate, dioxane glycol diacrylate (DOGDA, available from Sartomer as CD536), amine-modified polyether acrylate (available as PO 83 F, LR 8869, and / or LR 8889, all available from BASF Corporation), trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate (available from Sartomer as SR454), glycerol propoxylate triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate (available from Sartomer as SR Examples include (available as 494), as well as mixtures and combinations thereof.

[0049] The reactive diluent may be added in any desired or effective amount. For example, the reactive diluent may be added in an amount of about 1 to about 80% by weight of the carrier, such as about 10 to about 70% by weight of the carrier, or about 30 to about 50% by weight of the carrier.

[0050] In embodiments, the curable monomer may be added to the ink composition together with a tackifier such as a hydrocarbon tackifier. Other exemplary tackifiers include FORAL 85 (commercially available from Hercules), which is a glycerol ester of hydrogenated abietin(rosin) acid; FORAL 105 (commercially available from Hercules), which is a pentaerythritol ester of hydroabietin(rosin) acid; CELLOLYN 21 (commercially available from Hercules), which is a hydroabietin(rosin) alcohol ester of phthalic acid; ARAXAWA KE-311 resin (commercially available from Arakawa Chemical Industries), which is a triglyceride of hydrogenated abietin(rosin) acid; synthetic polyterpene resins such as NEVTAC 2300, NEVIAC 100, and NEVRAC 80 (commercially available from Neville Chemical Company); and WINGTACK 86 (commercially available from Goodyear), which is a modified synthetic polyterpene resin. If present, tackifiers may be present in the ink in any desired or effective amount, such as at least about 0.1% by weight, at least about 5%, at least about 10%, or no more than about 50% of the ink. Photoinitiator

[0051] In embodiments, the phase-change inks disclosed herein may include any suitable photoinitiator. Photoinitiators that absorb radiation, such as UV light, may be used to initiate the curing of the curable components of the ink. Ink compositions containing acrylate groups, or inks comprising polyamides, may include photoinitiators such as benzophenone, benzoin ether, benzyl ketal, α-hydroxyalkylphenone, α-alkoxyalkylphenone, α-aminoalkylphenone, and acylphosphine photoinitiators sold under the trade names IRGACURE and DAROCUR (available from BASF).Examples of suitable photoinitiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide (available from BASF as LUCIRIN TPO), 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (available from BASF as LUCIRIN TPO-L), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (available from BASF as IRGACURE 819) and other acylphosphines, 2-methyl-1-(4-methylthio)phenyl-2-(4-morpholinyl)-1-propane (available from BASF as IRGACURE 907) and 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methylpropan-1-one (available from BASF as IRGACURE 2959), and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1 (available from BASF as IRGACURE (Available as 369), 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)-benzyl)-phenyl)-2-methylpropan-1-one (Available from BASF as IRGACURE 127), 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholine-4-ylphenyl)-butanone (Available from BASF as IRGACURE 379), titanocene, isopropylthioxanthone (Available from BASF as Darocur Examples include 1-hydroxycyclohexylphenyl ketone, benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzoylphenylphosphinate ethyl ester, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propane), 2-hydroxy-2-methyl-1-phenyl-1-propane, benzyl-dimethyl ketal, and mixtures thereof. Amine synergies may also be used. Amine synergies are co-initiators that donate hydrogen atoms to the photoinitiator, thereby forming a radical species that initiates polymerization (amine synergies may also consume oxygen dissolved in the ink, and since oxygen inhibits free radical polymerization, its consumption increases the polymerization rate).Examples of exemplary amine synergies include, for example, ethyl-4-dimethylaminobenzoate and 2-ethylhexyl-4-dimethylaminobenzoate. This list is not exhaustive, and any known photoinitiator that initiates a free radical reaction upon exposure to a desired wavelength of radiation, such as UV light, may be used without limitation.

[0052] Optionally, the phase-change ink may also contain an amine synergist, which is a co-initiator that can donate hydrogen atoms to the photoinitiator, thereby forming a radical species that initiates polymerization, and can also consume dissolved oxygen that inhibits free radical polymerization, thereby increasing the polymerization rate. Examples of suitable amine synergists include ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-4-dimethylaminobenzoate, and mixtures thereof.

[0053] Photoinitiators can initiate curing by absorbing radiation with wavelengths of approximately 200 to 420 nm, but the use of initiators that absorb longer wavelengths, such as titanocene which can absorb up to 560 nm, is also permitted without limitation.

[0054] The total amount of initiator contained in the ink composition may be about 0.5 to about 15% by weight of the ink composition, for example, about 1 to about 10% by weight. Reactive wax

[0055] The phase-change ink compositions disclosed herein may include a reactive wax. In embodiments, the reactive wax may include a curable wax component that is miscible with other components and polymerizes with a curable monomer to form a polymer. The inclusion of the wax facilitates an increase in the viscosity of the ink as it cools from the spray temperature.

[0056] Exemplary waxes include those functionalized with curable groups. In embodiments, curable groups may include acrylates, methacrylates, alkenes, allyl ethers, epoxides, and oxetanes. These waxes can be synthesized by reaction with waxes having convertible functional groups, such as carboxylic acids or hydroxyls.

[0057] Preferred examples of hydroxyl-terminated polyethylene waxes that can be functionalized using curable groups include mixtures of carbon chains having the structure CH3-(CH2)n-CH2OH, where a mixture of chain lengths n exists, and in embodiments, the average chain length is in the range of about 16 to about 50, and are linear low molecular weight polyethylenes with similar average chain lengths. Preferred examples of such waxes include UNILIN® 350, UNILIN® 425, UNILIN® 550, and UNILIN® 700, which have Mn approximately equal to 375, 460, 550, and 700 g / mol, respectively. All of these waxes are commercially available from Baker-Petrolite. Guerbet alcohols characterized as 2,2-dialkyl-1-ethanol are also preferred compounds. Specific embodiments of Guerbet alcohols include those containing 16 to 36 carbon atoms, many of which are commercially available from Jarchem Industries Inc. (Newark, NJ). In the embodiment, PRIPOL® 2033 is selected, which is a C-36 dimer diol mixture and other branched isomers available from Uniqema (New Castle, DE) that may contain unsaturated and cyclic groups. These alcohols can react with carboxylic acids having UV-curable moieties to form reactive esters. Examples of these acids include acrylic and methacrylic acids available from Sigma-Aldrich. Specific curable monomers include acrylates of UNILIN® 350, UNILIN® 425, UNILIN® 550, and UNILIN® 700.

[0058] Preferred examples of carboxylic acid-terminated polyethylene waxes that can be functionalized using curable groups include mixtures of carbon chains having the structure CH3-(CH2)n-COOH, where a mixture of chain lengths n exists, and in selected embodiments, the average chain length is in the range of about 16 to about 50, and are linear low molecular weight polyethylenes of similar average chain lengths. Preferred examples of such waxes include UNICID® 350, UNICID® 425, UNICID® 550, and UNICID® 700, which have Mn approximately equal to 390, 475, 565, and 720 g / mol, respectively. Other preferred waxes have the structure CH3-(CH2)n-COOH, for example, n=14 with hexadecanoic acid or palmitic acid, and n=15 with heptadecanoic acid, margaric acid, or daturic acid. The compounds include n=16 octadecanoic acid or stearic acid, n=18 eicosanoic acid or arachidic acid, n=20 docosanoic acid or behenic acid, n=22 tetracosanoic acid or lignoceric acid, n=24 hexacosanoic acid or cerotic acid, n=25 heptacosanoic acid or carboceric acid, n=26 octacosanoic acid or montanic acid, n=28 triacontanoic acid or melisic acid, n=30 dotriacontanoic acid or raceroic acid, n=31 tritriacontanoic acid or ceromeric acid or thyric acid, n=32 tetratriacontanoic acid or gesic acid, and n=33 pentatricontanoic acid or ceroplastic acid. Guerbeic acid, characterized as a 2,2-dialkylethaneic acid, is also a preferred compound. Selected gerbetic acids include those containing 16 to 36 carbon atoms, many of which are commercially available from Jarchem Industries Inc. (Newark, NJ). PRIPOL® 1009, available from Uniqema (New Castle, DE), and other branched isomers that may contain unsaturated and cyclic groups can also be used. These carboxylic acids can react with alcohols having UV-curable moieties to form reactive esters. Examples of these alcohols include Sigma-Aldrich's 2-allyloxyethanol.

[0059] [ka]

[0060] Sartomer Company, Inc.'s SR495B,

[0061] [ka]

[0062] Examples include CD572 (R=H, n=10) and SR604 (R=Me, n=4) from Sartomer Company, Inc.

[0063] In embodiments, an optional curable wax is included in the ink in an amount of about 1 to about 25% by weight of the ink, such as about 2 to about 20% by weight of the ink, or about 2.5 to about 15% by weight of the ink.

[0064] The curable monomer or prepolymer and the curable wax together may form more than about 50% by weight of the ink, or at least 70% by weight of the ink, or at least 80% by weight of the ink. Gelling agent

[0065] The antimicrobial phase-changing ink compositions disclosed herein may contain any suitable gelling agent. The gelling agent functions to dramatically increase the viscosity of the ink vehicle and the ink composition within a desired temperature range. In particular, the gelling agent forms a semi-solid gel in the ink vehicle at temperatures below a specific temperature at which the ink composition is sprayed. The semi-solid gel phase is a physical gel that exists as a dynamic equilibrium consisting of one or more solid gelling agent molecules and a liquid solvent. The semi-solid gel phase is a dynamically networked assembly of molecular components held together by non-covalent interactions such as hydrogen bonds, van der Waals interactions, aromatic non-bonding interactions, ionic or coordination bonds, and London dispersion forces, and can reversibly transition from a liquid to a semi-solid state at a macroscopic level when stimulated by temperature, mechanical stirring, or physical forces such as chemical forces such as pH or ionic strength. The ink composition exhibits a thermally reversible transition between the semi-solid gel state and the liquid state when the temperature changes above or below the gel phase transition. This reversible cycle of transition between the semi-solid gel phase and the liquid phase can be repeated many times in the ink composition. A phase transition can be performed using a mixture of one or more gelling agents.

[0066] By utilizing the phase-change properties of the gelling agent, a rapid increase in viscosity can be induced in the sprayed ink composition after the ink is sprayed onto the substrate. In particular, the sprayed ink droplets can be fixed in place on the receiving substrate at a temperature lower than the ink spraying temperature of the ink composition through the action of the phase-change transition.

[0067] The temperature at which the ink composition forms a gel state is any temperature below the injection temperature of the ink composition, for example, any temperature at least 10°C lower than the injection temperature of the ink composition. A rapid and significant increase in ink viscosity occurs during cooling from the injection temperature, where the ink composition is in a liquid state, to the gel transition temperature, where the ink composition is converted to a gel state. In some embodiments, the ink composition may exhibit a viscosity increase of at least 10²⁵ times.

[0068] Suitable gelling agents can rapidly and reversibly gel monomers / oligomers in the ink vehicle and demonstrate a narrow phase transition, for example, within a temperature range of about 20°C to about 85°C. The gel state of an exemplary ink composition should show a viscosity increase of 102.5 mPa·s or more, for example 103 mPa·s, at the substrate temperature, for example, about 30°C to about 70°C, compared to the viscosity at the spray temperature. In some embodiments, the gelling agent-containing ink composition exhibits a rapid viscosity increase at temperatures 5°C to 10°C lower than the spray temperature, eventually reaching a viscosity greater than 10⁴ times the spray viscosity, for example, about 10⁵ times the spray viscosity.

[0069] Suitable gelling agents include radiation-curable gelling agents comprising curable amides, curable polyamide-epoxyacrylate components, and polyamide components, curable composite gelling agents comprising curable epoxy resins and polyamide resins, and mixtures thereof, which are disclosed in U.S. Patent No. 8,334,026, the entirety of which is incorporated herein by reference. By including a gelling agent in a composition, the composition can be applied to a substrate, for example, one or more portions of a substrate and / or one or more portions of an image pre-formed on the substrate, without excessive penetration into the substrate because the viscosity of the composition increases rapidly as the composition cools after application. Excessive penetration of liquid into porous substrates such as paper can result in an undesirable decrease in the opacity of the substrate. Curable gelling agents may also be involved in the curing of monomers of the composition.

[0070] Gelling agents can be amphiphilic, which essentially improves wettability when the composition is used on a substrate having silicone or other oils on it. "Amphiphilic" refers to a molecule that has both polar and nonpolar parts. For example, a gelling agent may have a long nonpolar hydrocarbon chain and a polar amide bond.

[0071] Examples of amide gelling agents are those described in U.S. Patents No. 7,531,582, No. 7,276,614, and No. 7,279,587, the entire disclosures of which are incorporated herein by reference.

[0072] The amide gelling agent may be a compound of the following formula (I):

[0073] [ka]

[0074] In equation (I), R1 is

[0075] (i) an alkylene group having approximately 1 to 12 carbon atoms, such as approximately 1 to 8 or approximately 1 to 5 carbon atoms (an alkylene group is a divalent aliphatic group or alkyl group, including linear and branched, saturated and unsaturated, cyclic and acyclic, and substituted and unsubstituted alkylene groups, and heteroatoms such as oxygen, nitrogen, sulfur, silicon, phosphorus, and boron may or may not be present in the alkylene group),

[0076] (ii) Arylene groups having approximately 1 to 15 carbon atoms, such as approximately 3 to 10 or approximately 5 to 8 carbon atoms (arylene groups are divalent aromatic groups or aryl groups, including substituted and unsubstituted arylene groups, and heteroatoms such as oxygen, nitrogen, sulfur, silicon, phosphorus, and boron may or may not be present in the arylene group),

[0077] (iii) an arylalkylene group having approximately 6 to approximately 32 carbon atoms, such as approximately 6 to approximately 22 carbon atoms, or approximately 6 to approximately 12 carbon atoms (the arylalkylene group is a divalent arylalkyl group, including substituted and unsubstituted arylalkylene groups, and the alkyl portion of the arylalkyl group may be linear or branched, saturated or unsaturated, and cyclic or acyclic, and heteroatoms such as oxygen, nitrogen, sulfur, silicon, phosphorus, and boron may or may not be present in the aryl or alkyl portion of the arylalkylene group), or

[0078] (iv) an alkylarylene group having approximately 5 to 32 carbon atoms, such as approximately 6 to 22 or approximately 7 to 15 carbon atoms (an alkylarylene group is a divalent alkylaryl group, including substituted and unsubstituted alkylarylene groups, and the alkyl portion of the alkylarylene group may be linear or branched, saturated or unsaturated, and cyclic or acyclic, and heteroatoms such as oxygen, nitrogen, sulfur, silicon, phosphorus, and boron may or may not be present in the aryl or alkyl portion of the alkylarylene group).

[0079] Unless otherwise specified, substituents on the substituted alkyl, aryl, alkylene, arylene, arylalkylene, and alkylarylene groups disclosed above and below may be selected from halogen atoms, cyano groups, pyridine groups, pyridinium groups, ether groups, aldehyde groups, ketone groups, ester groups, amide groups, carbonyl groups, thiocarbonyl groups, sulfide groups, nitro groups, nitroso groups, acyl groups, azo groups, urethane groups, urea groups, and mixtures thereof. Optionally, two or more substituents may bond together to form a ring.

[0080] In equation (I), R2 and R2' are independent of the other,

[0081] (i) an alkylene group having approximately 1 to 54 carbon atoms, such as approximately 1 to 48 carbon atoms or approximately 1 to 36 carbon atoms,

[0082] (ii) Arylene groups having approximately 5 to 15 carbon atoms, such as approximately 5 to 13 or approximately 5 to 10 carbon atoms,

[0083] (iii) an arylalkylene group having approximately 6 to 32 carbon atoms, such as approximately 7 to 33 carbon atoms or approximately 8 to 15 carbon atoms,

[0084] (iv) It may be an alkylene arylene group having approximately 6 to 32 carbon atoms, such as approximately 6 to 22 carbon atoms or approximately 7 to 15 carbon atoms.

[0085] In equation (I), R3 and R3' are independent of the other,

[0086] (a) Photoinitiating groups such as groups derived from 1-(4-(2-hydroxyethoxy)phenyl)-2-hydroxy-2-methylpropan-1-one of formula (II),

[0087] [ka]

[0088] The group derived from 1-hydroxycyclohexylphenyl ketone of formula (III),

[0089] [ka]

[0090] The group derived from 2-hydroxy-2-methyl-1-phenylpropan-1-one of formula (IV),

[0091] [ka]

[0092] A group derived from N,N-dimethylethanolamine or N,N-dimethylethylenediamine of formula (V),

[0093] [ka]

[0094] etc., or,

[0095] (b)

[0096] (i) alkyl groups having approximately 2 to 100 carbon atoms, such as approximately 3 to 60 or approximately 4 to 30 carbon atoms (alkyl groups include linear and branched, cyclic and acyclic, and substituted and unsubstituted alkyl groups, and heteroatoms such as oxygen, nitrogen, sulfur, silicon, phosphorus, and boron may be optionally present in the alkyl group),

[0097] (ii) Aryl groups such as phenyl (including substituted and unsubstituted aryl groups) having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 or approximately 6 to 30 carbon atoms.

[0098] (iii) Arylalkyl groups such as benzyl having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms,

[0099] (iv) The group may be an alkylaryl group such as a tolyl having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms.

[0100] In addition, in formula (I), X and X' can each be an oxygen atom or a group of formula -NR4-, independently of the other, where R4 is

[0101] (i) Hydrogen atom,

[0102] (ii) alkyl groups having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms.

[0103] (iii) Aryl groups having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms,

[0104] (iv) Arylalkyl groups having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms,

[0105] (v) an alkylaryl group having approximately 5 to 100 carbon atoms, such as approximately 5 to 60 carbon atoms or approximately 6 to 30 carbon atoms.

[0106] Further details can be found, for example, in U.S. Patent Nos. 7,279,587 and 7,276,614.

[0107] The gelling agent may be a composite gelling agent, for example, a gelling agent comprising a curable epoxy resin and a polyamide resin. Suitable composite gelling agents are generally described in U.S. Patent No. 7,563,487, the entire disclosure of which is incorporated herein by reference.

[0108] The epoxy resin component in the composite gelling agent can be any suitable epoxy group-containing material. Examples of epoxy group-containing components include diglycidyl ethers of either polyphenol-based epoxy resins or polyol-based epoxy resins, or mixtures thereof. That is, the epoxy resin has two epoxy functional groups located at the ends of the molecule. Polyphenol-based epoxy resins are bisphenol A-co-epichlorohydrin resins having two or fewer glycidyl ether-terminated groups. Polyol-based epoxy resins may be dipropylene glycol-co-epichlorohydrin resins having two or fewer glycidyl ether-terminated groups. Suitable epoxy resins have a weight-average molecular weight in the range of about 200 to about 800, such as about 300 to about 700. Commercially available sources of epoxy resins include, for example, bisphenol A-based epoxy resins such as DER 383 from Dow Chemical Corp, and dipropylene glycol-based resins such as DER 736 from Dow Chemical Corp. Other sources of epoxy materials derived from natural sources may be used, such as epoxidized triglyceride fatty esters of plant or animal origin, e.g., epoxidized linseed oil, rapeseed oil, or mixtures thereof. Epoxy compounds derived from vegetable oils, such as the VIKOFLEX line of Arkema Inc. (Philadelphia, PA), may also be used. Thus, epoxy resin components are functionalized with acrylates or (meth)acrylates, vinyl ethers, allyl ethers, etc., by chemical reaction with unsaturated carboxylic acids or other unsaturated reagents. For example, terminal epoxide groups of the resin are ring-opened in this chemical reaction and converted to (meth)acrylate esters by esterification with (meth)acrylic acid.

[0109] Any suitable polyamide material can be used as the polyamide component of the epoxy-polyamide composite gelling agent. The polyamide consists of polyamide resins derived from polyamines such as polymerized fatty acids, including those obtained from natural sources (e.g., palm oil, rapeseed oil, castor oil, and mixtures thereof), or generally known hydrocarbons "dimer acids" prepared from dimerized C-18 unsaturated acid raw materials such as oleic acid and linoleic acid, and diamines (e.g., alkylenediamines such as DYTEK series diamines, ethylenediamine, and poly(alkyleneoxy)diamine), or polyamide copolymers such as polyester-polyamide and polyether-polyamide. One or more polyamide resins can be used to form the gelling agent. Commercial sources of polyamide resins include, for example, the VERSAMID series of polyamides (available from Cognis Corporation (formerly Henkel Corp.)), in particular VERSAMID 335, VERSAMID 338, VERSAMID 795, and VERSAMID 963, all of which have low molecular weight and low amine numbers, and their variants, including SYLVAGEL polyamide resins (available from Arizona Chemical Company) and polyether-polyamide resins, can be used. The composition of SYLVAGEL resin obtained from Arizona Chemical Company is described as a polyalkylene oxydiamine polyamide having general formula (IX),

[0110] [ka]

[0111] In the formula, R1 is an alkyl group having at least 17 carbon atoms, R2 includes a polyalkylene oxide, R3 includes a C-6 carboncyclic group, and n is at least an integer of 1.

[0112] Gelling agents may also include curable polyamide-epoxyacrylate components and polyamide components, such as those generally disclosed in U.S. Patent No. 7,632,546, the entire disclosure of which is incorporated herein by reference. Curable polyamide-epoxyacrylates are curable by containing at least one functional group. For example, polyamide-epoxyacrylates are bifunctional. Functional groups such as acrylate groups(s) are radiation-curable via free radical initiation, enabling chemical bonding of the gelling agent to the curing ink vehicle. A commercially available polyamide-epoxyacrylate is Cognis PHOTOMER RM370. Curable polyamide-epoxyacrylates may also be selected from the above structures for curable composite gelling agents comprising curable epoxy resins and polyamide resins.

[0113] The ink composition may contain a gelling agent in any suitable amount, such as about 1 to about 50% by weight, or about 2 to about 20% by weight, or about 3 to about 10% by weight of the ink.

[0114] Many of the compounds prepared in this manner may exhibit gel-like behavior when present in solution. Examples of materials in which these compounds can dissolve include curable monomers such as propoxylated neopentyl glycol diacrylate, such as SR9003®, commercially available from Sartomer Co., Inc. "Gel-like behavior" refers to the compound undergoing a relatively rapid increase in viscosity over a relatively narrow temperature range. Some compounds disclosed herein undergo a viscosity change of at least about 10³ centipoise, at least about 10⁵ centipoise, or at least about 10⁶ centipoise over a temperature range of at least about 5°C, at least about 10°C, or at least about 30°C, although viscosity changes and temperature ranges may be outside these ranges, and compounds that do not undergo changes within these ranges are also included herein. Coloring agents

[0115] The antimicrobial phase-change ink compositions disclosed herein may optionally contain a colorant. The optional colorant, if present, may be present in the colored marking material in any desired amount, for example, about 0.5 to about 75% by weight of the marking material, such as about 1 to about 50% by weight of the marking material, or about 1 to about 25% by weight of the marking material.

[0116] Any suitable colorants may be used in the embodiments herein and include dyes, pigments, or combinations thereof. Examples of colorants include any dyes or pigments that can be dispersed or dissolved in the vehicle. Examples of suitable pigments include, for example, Paliogen Violet 5100 (BASF), Paliogen Violet 5890 (BASF), Heliogen Green L8730 (BASF), Lithol Scarlet D3700 (BASF), SUNFAST® Blue 15:4 (Sun Chemical 249-0592), HOSTAPERM Blue B2G-D (Clariant), Permanent Red P-F7RK, HOSTAPERM Violet BL (Clariant), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Company), Oracet Pink RF (Ciba), Paliogen Red 3871 K (BASF), SUNFAST® Blue 15:3 (Sun Chemical 249-1284), Paliogen Red 3340 (BASF), and SUNFAST® Carbazole Violet. 23 (Sun Chemical 246-1670), Lithol Fast Scarlet L4300 (BASF), Sunbrite Yellow 17 (Sun Chemical 275-0023), Heliogen Blue L6900, L7020 (BASF), Sunbrite Yellow 74 (Sun Chemical 272-0558), SPECTRA PAC®C Orange 16 (Sun Chemical 276-3016), Heliogen Blue K6902, K6910(BASF), SUNFAST(R) Magenta 122(Sun Chemical 228-0013), Heliogen Blue D6840, D7080(BASF), Sudan Blue OS(BASF), Neopen Blue FF4012(BASF), PV Fast Blue B2GO1 (Clariant), Irgalite Blue BCA (Ciba), PaliogenBlue 6470(BASF), Sudan Orange G(Aldrich), Sudan Orange 220(BASF), Paliogen Orange 3040(BASF), Paliogen Yellow 152, 1560(BASF), Lithol Fast Yellow 0991 K(BASF), Paliotol Yellow 1840(BASF), Novoperm Yellow FGL(Clariant), Lumogen Yellow D0790(BASF), Suco-Yellow L1250(BASF), Suco-Yellow D1355(BASF), Suco Fast Yellow Dl 355, Dl 351(BASF), Hostaperm Pink E 02(Clariant), Hansa Brilliant Yellow 5GX03(Clariant), Permanent Yellow GRL 02(Clariant), Permanent Rubine L6B Examples of carbon blacks include 05 (Clariant), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Paliogen Black L0084 (BASF), Pigment Black K801 (BASF), and REGAL 330 (trademark) (Cabot), Carbon Black 5250, Carbon Black 5750 (Columbia Chemical), and mixtures thereof. Examples of suitable dyes include Usharect Blue 86 (Direct Blue 86) from Ushanti Color, Intralite Turquoise 8GL (Direct Blue 86) from Classic Dyestuffs, Chemical Brilliant Red 7BH (Reactive Red 4) from Chemiequip, Levafix Black EB from Bayer, Reactron Red H8B (Reactive Red 31) from Atlas Dye-Chem, D&C Red #28 (Acid Red 92) from Warner-Jenkinson, and GlobalExamples include Direct Brilliant Pink B from Color, Acid Tartrazine from Metrochem Industries, and Cartasol Yellow 6GF Clariant and Carta Blue 2GL from Clariant. Examples of solvent dyes are Neozapon Red 492 (BASF), Orasol Red G (Ciba), Direct Brilliant Pink B (Global Colors), Aizen Spilon Red C-BH (Hodogaya Chemical), Kayanol Red 3BL (Nippon Kayaku), Spirit Fast Yellow 3G, Aizen Spilon Yellow C-GNH (Hodogaya Chemical), Cartasol Brilliant Yellow. 4GF(Clariant), Pergasol Yellow CGP(Ciba), Orasol Black RLP(Ciba), Savinyl Black RLS(Clariant), Morfast Black Conc.A(Rohm and Haas), Orasol Blue GN(Ciba), Savinyl Blue GLS(Sandoz), Luxol Fast Blue MBSN(Pylam), Sevron Blue 5GMF(Classic Dyestuffs), Basacid Blue 750 (BASF), Neozapon Examples of volatile solvent-soluble dyes include Black X51 (CISolvent Black, CI12195) (BASF), Sudan Blue 670 (CI61554) (BASF), Sudan Yellow 146 (CI12700) (BASF), Sudan Red 462 (CI260501) (BASF), and mixtures thereof. Antioxidant

[0117] The antimicrobial phase-change ink compositions disclosed herein may also optionally contain antioxidants. Optional antioxidants can protect images from oxidation and can also protect ink components from oxidation during the heating portion of the ink preparation process. Specific examples of suitable antioxidant stabilizers include NAUGARD® 524, NAUGARD® 635, NAUGARD® A, NAUGARD® I-403, and NAUGARD® 959, commercially available from Crompton Corporation (Middlebury, CT); IRGANOX® 1010 and IRGASTAB® UV 10, commercially available from Ciba Specialty Chemicals; GENORAD 16 and GENORAD 40, commercially available from Rahn AG (Zurich, Switzerland), and mixtures thereof. If present, optional antioxidants are present in the ink in any desired or effective amount. For example, optional antioxidants may be present in amounts of approximately 0.01 to 20% by weight, such as approximately 0.1 to 10% by weight or approximately 1 to 5% by weight of the ink carrier. Antimicrobial additives

[0118] In embodiments, the antimicrobial phase-changing ink composition may include an ionic polymer-metal composite, where the ionic polymer-metal composite nanoparticles act as a reservoir for supplying metal ions for antibacterial, antifungal, antiviral biocide effects, or a combination thereof. In certain embodiments, the composite nanoparticles include a core and a shell, where the core optionally includes a styrene / acrylate polymer core resin containing a metal, and the shell contains a metal.

[0119] Any suitable desired metal may be selected for the embodiments herein if the metal imparts the desired antibacterial, antifungal, antiviral biocide effect, or a combination thereof. Other metals may be used, but only certain ones possess antibacterial properties. In embodiments, Co, Cu, Ni, Au, and Pd may be used in silver composites, where Co, Cu, Ni, Au, Pd, or mixtures or combinations thereof may impart antibacterial and / or antimicrobial properties. See, for example, Yasuyuki M, Kunihiro K, Kurissery S, et al. Biofouling 2010 Oct;26(7):851-8) describing Co, Cu, Ni, and Au (and Pd). In embodiments, Ag and Cu are selected. In other embodiments, composites including Pt, Al, Cr, In, and mixtures and combinations thereof may be selected.

[0120] In some embodiments, silver nanoparticles may consist solely of the element silver, or they may be silver composites or alloys that include composites or alloys with other metals. Such metal-silver composites may consist of (i) one or more other metals and (ii) one or more nonmetals, either or both. Suitable other metals include, for example, Al, Au, Pt, Pd, Cu, Co, Cr, In, and Ni, and especially transition metals, such as Au, Pt, Pd, Cu, Cr, Ni, and mixtures thereof. Exemplary metal composites are Au-Ag, Ag-Cu, Au-Ag-Cu, and Au-Ag-Pd. Suitable nonmetals in metal composites include, for example, Si, C, and Ge. Various components of the silver composite may be present in amounts ranging from, for example, about 0.01% to about 99.9% by weight, and especially from about 10% to about 90% by weight. In embodiments, the silver composite is a metal alloy comprising silver and one or more other metals, wherein silver constitutes, for example, at least about 20% by weight of the nanoparticles, and more particularly, more than about 50% by weight of the nanoparticles. Unless otherwise specified, the weight percentages listed herein with respect to the components of the silver-containing nanoparticles do not include stabilizers.

[0121] Those skilled in the art will understand that metals other than silver may be useful and can be prepared in or combined with antimicrobial phase-change ink compositions according to the methods disclosed herein. For example, complexes may be prepared with nanoparticles of copper, gold, palladium, or complexes of such exemplary metals. See, for example, Adams CP, Walker KA, Obare SO, Docherty KM, PLoS One. 2014 Jan 20;9(1):e85981.doi:10.1371 / journal.pone.0085981, eCollection 2014, which describes palladium as an antimicrobial agent.

[0122] In the embodiment, the optional core metal, if present, is selected from the group consisting of silver, cobalt, copper, nickel, gold, palladium, and combinations thereof, and the shell metal is selected from the group consisting of silver, cobalt, copper, nickel, gold, palladium, and combinations thereof. In a particular embodiment, if the optional core metal is present, it is silver, and the shell metal is silver.

[0123] In some embodiments, the composite nanoparticle shell comprises a resin, the resin comprising a silver composite monomer selected from the group consisting of silver acrylate monomer, silver methacrylate monomer, and combinations thereof. In certain embodiments, the composite nanoparticle shell comprises a resin, the resin comprising a silver composite monomer selected from the group consisting of silver acrylate monomer, silver methacrylate monomer, and combinations thereof, the silver composite monomer present in the shell resin in an amount of about 0.01% to about 10% by weight, or about 0.05% to about 8% by weight, or about 0.05% to about 4% by weight, based on the total weight of the shell resin.

[0124] In the embodiment, the composite nanoparticle shell comprises a resin, the shell resin comprising a comonomer selected from the group consisting of methyl methacrylate, butyl acrylate, diacrylate, cyclohexyl methacrylate, styrene, methacrylic acid, dimethylaminoethyl methacrylate, and combinations thereof.

[0125] In the embodiment, the core resin comprises a silver composite monomer selected from the group consisting of silver acrylate monomer, silver methacrylate monomer, and combinations thereof.

[0126] In the embodiment, if an optional core metal is present, the shell metal comprises a composite of silver and one or more other metals; or if an optional core metal is present, the shell metal comprises a composite of silver and one or more nonmetals; or if an optional core metal is present, the shell metal comprises a composite of silver, one or more other metals, and one or more nonmetals.

[0127] In embodiments, the composite may include, but is not limited to, carbon nanotubes (CNTs including single-layer, double-layer, and multi-layer), graphene sheets, nanoribbons, nanoanions, hollow nanoshell metals, nanowires, and other nanostructured materials. In embodiments, CNTs may be added in amounts that enhance electrical and thermal conductivity. The shell may include a resin containing a metal or a reduced metal and may cover the entire surface of the core particle or a portion thereof. Thus, the shell may encompass the entire outer surface of the particle, thereby encapsulating the core particle, or it may appear as isolated patches of varying sizes, such as islands, on the surface of the core, for example.

[0128] In embodiments, composite core / shell nanoparticles are provided, the core may optionally contain a metal and may contain a styrene / acrylate resin, and the shell may contain at least one composite styrene / acrylate-metal ion polymer resin, such as the silver ionomer described above. The core may be prepared by polymerization, such as emulsion polymerization of acrylate and styrene monomers. The shell resin may be prepared as described above and then added to an emulsion of core particles to form a shell that encapsulates the core resin particles. In embodiments, the shell resin is synthesized on the core particles and appropriate shell monomers and initiators are added to the core particles. In embodiments, metal ions are reduced on the resin or on the core particles to form a shell thereon. In embodiments, the metal may be reduced during core formation. In embodiments, the metal may be reduced on the core. In embodiments, the metal may be reduced on the shell.

[0129] In embodiments, antimicrobial phase-change ink compositions, such as those disclosed herein, may contain silver metal ions. Silver metal ions are known to possess antimicrobial properties and may be referred to as antimicrobial metal ions. Suitable antimicrobial metals, metal nanoparticles, and metal ions include, but are not limited to, those considered above, as well as silver, copper, zinc, gold, mercury, tin, lead, iron, cobalt, nickel, manganese, arsenic, antimony, bismuth, barium, cadmium, chromium, and thallium. For example, metal ions of silver, copper, zinc, and gold, or combinations thereof, are considered safe for human use. Therefore, silver ions, alone or in combination with copper or zinc or both, have a high efficacy-to-toxicity ratio, i.e., high efficacy and low toxicity. In some embodiments, the antimicrobial phase-change ink compositions disclosed herein may include other metallic or metal oxide or metal oxide nanoparticles exhibiting antimicrobial and biocide activity, including copper oxide, silver, gold, zinc oxide, zinc pyrithione, calcium oxide, iron(III) oxide, titanium dioxide, and magnesium oxide, as well as others known in the art.

[0130] In some embodiments, the antimicrobial phase-changing ink compositions disclosed herein may contain biguanides or bisbiguanides. Biguanides are organic compounds having the general formula HN(C(NH)NH2)2. Most biguanides are water-soluble, colorless solids that yield very basic solutions. These biguanide solutions can be slowly hydrolyzed to ammonia and urea. Bisbiguanides are a related category of chemically related compounds whose bactericidal properties are also known. Examples of these compounds include the preservatives chlorhexidine, polyaminopropyl biguanides (PAPB), polyhexanides, and alexidine. Chlorhexidine, for example, is a cationic bisbiguanide that disrupts the cell membranes of microorganisms and precipitates their contents, and is widely used as a skin preservative in veterinary medicine. Chlorhexidine has sustained activity on the skin, is non-irritating, is active in the presence of body fluids, and has rapid bactericidal activity.

[0131] In some embodiments, antimicrobial phase-change ink compositions, such as those disclosed herein, may contain N-halamine molecules. N-haloamine-containing complexes and coatings are known to possess broad biocide effects against microorganisms, long-term stability, renewability, safety for humans and the environment, and low cost. N-halamines are compounds containing one or more nitrogen-halogen covalent bonds, generally formed by the halogenation of imide, amide, or amine groups. Upon contact with N-halamine or N-halamine-containing materials, microorganisms undergo halogen exchange reactions, leading to the cessation of their cellular lifespan. Compared to inorganic halogens such as chlorine or bromine, organic N-halamines are more stable, less corrosive, and far less likely to generate halogenated hydrocarbons. Examples of N-halamines useful in antimicrobial compositions include monomeric N-haloamines such as 1,3-dichloro-5,5-dimethylhydantoin, 3-bromo-1-chloro-5,5-dimethylhydantoin, and 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone.

[0132] In some embodiments, antimicrobial phase-changing ink compositions, such as those disclosed herein, may contain quaternary ammonium compounds (QACs). Quaternary ammonium compounds (QACs), also sometimes referred to as quats, may be useful as biocides in several applications, such as wound dressings, lotions, cleansers, and those described herein. These compounds are cationic surfactants, or positively charged surfactants, that affect cell walls and membranes after relatively long contact times. The permanent positive charge of QACs readily binds them to the negatively charged surfaces of most microorganisms. QACs are generally very stable, unaffected by pH levels in most cases, and remain effective on surfaces for extended periods. While the antimicrobial activity of QACs may be more selective than other bactericides, they are generally very effective against bacterial biofilms. Examples of QACs include benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, dophanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, domiphene bromide, and others known in the art.

[0133] Typical amounts of antibacterial additives, antimicrobial additives, or biocide additives may range from about 0.01% to about 30% by weight of the total weight of the antimicrobial phase-change ink composition, or from about 0.1% to about 2.0% by weight, or from about 1% to about 10% by weight of the total weight of the antimicrobial phase-change ink composition. Characterization of engineered surface topography and textured surfaces

[0134] In certain embodiments, the combination of the antimicrobial phase-altering ink compositions described herein with engineered surface topography provides favorable resistance of the surface to bacterial and microbial growth and / or contamination. These engineered topographic surfaces and their respective shapes may be characterized or described in several ways. Surface shapes may include protrusions, depressions, or other shapes produced by directly printing or transferring the antimicrobial phase-altering ink compositions onto various substrates. These shapes in certain embodiments may include a range of height, spacing, physical properties, or combinations thereof to achieve favorable surface interaction with various microorganisms or other potentially harmful spores or biological materials. In embodiments with simpler surfaces, a roughness coefficient (R) may be used as a measure of surface roughness or topographic properties related to bioadhesion control or maintenance. The roughness coefficient or R may be defined as the ratio of the actual surface area (Ract) to the geometric surface area (Rgeo); R = Ract / Rgeo. For simple surfaces, this roughness coefficient may be calculated from some conventional measurements such as surface shape measurement. 1 cm 2 In the example of a piece of material, if the sample is perfectly flat, both the actual surface area and the geometric surface area are 1 cm². 2The resulting roughness coefficient would be 1. Alternatively, if a flat surface is roughened by patterning, such as by using photolithography and / or selective etching, the resulting actual surface area will be much larger than the original geometric surface area due to the additional surface area provided by the sidewalls of the resulting depressions and / or protrusions. For example, if the resulting exposed surface area is twice the surface area of ​​the original flat surface, the R value would therefore be 2. In embodiments of antimicrobial coating compositions as described herein, the engineered surface topography may have a ratio of actual surface area to geometric surface area of ​​about X to about Y, or about X to about Y, or about X to about Y. The roughness of such a surface may be measured using contact and non-contact means, such as Ra, which measures the arithmetic mean deviation of the measured profile area; Rz, which measures the average peak-to-valley height of the profile within a single sampling length on the surface; or other surface morphometry methods known to those skilled in the art. In certain embodiments, Ra measurement may be used to characterize the smoothness of a sliding surface, while Rz measurement may be used to characterize the height of a surface or a specific protrusion or depression therefrom. Using Ra alone may miss some points, such as a single protrusion, but using both Ra and Rz together may be advantageous. Examples of contact surface shape measurement methods include a stylus-type roughness tester that may have a measurement resolution of about 1 nm and a maximum height measurement of 1 mm, and an atomic force microscope (AFM) that may have a measurement resolution of <0.01 nm and a maximum height measurement of 10 micrometers. Examples of non-contact surface shape measurement methods include a white light interferometer with a measurement resolution of <0.1 nm and a maximum height measurement of about 3 mm, or a laser microscope with a measurement resolution of about 0.1 nm and a maximum height measurement of about 7 mm.

[0135] The engineered roughness index, or ERI, is another method for characterizing such engineered surfaces. ERI is a dimensionless ratio known in the art in relation to the characterization of surface topography used for bioadhesion control or maintenance. Characterization using ERI can account for application-specific deformations of the topographic shape and mechanical properties of a particular substrate material having an engineered topographic surface. Furthermore, such engineered surface topography characterization can provide a more comprehensive quantitative consideration of engineered surface topography compared to Wenzel's roughness coefficient, which is the resistance of a solid surface to wetting with water, as described in Wenzel R N.1936, Ind Eng Chem 28:988-994, which is incorporated in its entirety by reference. Wenzel's consideration alone may not adequately capture the complex surfaces of engineered topography as described in this disclosure.

[0136] ERI can be expressed as a dimensionless ratio based on Wenzel's roughness coefficient, the percentage of the pressed surface, and the degrees of freedom of spore movement, as follows:

number

[0137] Here, r is the Wenzel roughness ratio, which refers to the ratio of the actual surface area to the projected planar surface area, where the actual surface area includes the area related to the tops of the shape, the walls of the shape, and the pressing areas between the shapes, and the projected planar surface area includes only the tops and pressing areas of the shape, n is the number of different surface shapes in the design of the surface, and φ is the area ratio of the tops of the different surface shapes. As an example, a perfectly smooth surface would have ERI = 0. In certain embodiments, in addition to what is known in the art relating to antifouling properties in marine applications, the use of this equation may allow for the modeling of the amount of microfouling spores per square millimeter. An increase in the ERI value is an indicator of a reduction in microfouling adhesion in known applications. In certain embodiments, unpatterned nanoscale rough surfaces, such as circular pillars with a diameter of 2 μm and an ERI of 5.0, or raised areas with a width of 2 μm and an ERI of 6.1, reduce fouling and adhesion by 36% and 31%, respectively, while more regularly patterned surfaces consisting of circular pillars with a diameter of 2 μm and equilateral triangles of 10 μm with an ERI of 8.7 reduce spore adhesion by 58%.

[0138] In additional sources of information in this technical field, for example, Callow et al., "Trends in the development of environmentally friendly fouling-resistant marine coatings," Nature Communications (2011), which is incorporated in its entirety by reference, also mentions ERII and ERIII, which involve additional surface geometric parameters.

number

[0139] Here, r is the Wenzel roughness coefficient, (1-φs) is the area ratio of the shape apex, i.e., the ratio of the pressed surface area between shapes to the projected planar surface area, and df is the degree of freedom of spore movement (1 or 2). Spore fixation is ER IIIt may be shown that it decreases with increasing . The hydrophobicity of the surface material, such as measured by the contact angle, or other surface measurements known in the art, is also related in some embodiments to surface roughness, such as obtained by the Wenzel roughness coefficient. In certain embodiments, properties of the topographic shape, such as bending moment or stiffness, may also result in nanoforce gradients that lead to spore adhesion. In other words, the generation of nanoforce gradients can be considered as a function of the bending moment or stiffness of the protruding topographic shape in contact with the cell. This concept, considering the numerous different shapes on the topographic surface, is related to the revised ERI model (ER) known to those skilled in the art. III In this context, df may be another predictor of topographic inhibition that led to the substitution of n.

[0140] Antimicrobial coating compositions as described herein may have an engineered roughness index (ERI) characterized by any of the models described, ranging from about 5 to about 50, or about 5 to about 30, or about 7 to about 20. Antimicrobial coating compositions as described herein may have an engineered surface topography having an actual surface area to geometric surface area ratio of about 2 to about 40, or about 4 to about 30, or about 10 to about 30. Antimicrobial coating compositions as described herein may have an engineered surface topography including protruding shapes spaced about 1 to about 5000 nm, about 250 nm to about 2000 nm, or about 500 nm to about 1000 nm apart. Antimicrobial coating compositions as described herein may have protruding shapes having heights of about 10 to about 5000 nm, about 400 nm to about 2000 nm, or about 500 nm to about 1000 nm. Printing equipment and processes

[0141] The radiation-curable antimicrobial phase-change ink composition and the methods described herein may be used in any desired printing system, including systems suitable for preparing three-dimensional objects, such as solid object printers, thermal inkjet printers (both liquid inks and phase-change inks at room temperature), piezoelectric inkjet printers (both liquid inks and phase-change inks at room temperature), acoustic inkjet printers (both liquid inks and phase-change inks at room temperature), thermal transfer printers, gravure printers, and electrostatic printing methods (both using dry marking materials and using liquid marking materials). In other embodiments, the ink material may be used for the manual preparation of three-dimensional objects, either through the use of a mold or by manual deposition of the ink material, to prepare a desired structured or textured surface or three-dimensional object.

[0142] Inkjet printing devices are known in the art. For example, inkjet printing devices generally come in two types: continuous flow and drop-on-demand. In a continuous flow inkjet system, ink is ejected as a continuous flow under pressure through at least one orifice or nozzle. The flow is disturbed, causing it to break down into droplets at a certain distance from the orifice. At the point of breakdown, the droplets are charged according to a digital data signal and passed through an electrostatic field that modulates the trajectory of each droplet in order to direct them to a recirculation gutter or a specific location on the recording medium. In a drop-on-demand system, droplets are ejected directly from the orifice to a location on the recording medium according to a digital data signal. Droplets are neither formed nor ejected except when they are placed on the recording medium.

[0143] Generally, there are three types of drop-on-demand inkjet systems. One type of drop-on-demand system has, as its main components, an ink-filled channel or passage with a nozzle at one end and a piezoelectric device with a piezoelectric vibrator that generates pressure pulses near the other end. Another type of drop-on-demand system is known as acoustic ink printing. As is known, an acoustic beam exerts radiation pressure on an object it strikes. Therefore, when an acoustic beam strikes the free surface of a pool of liquid (i.e., the liquid / air interface) from below, the radiation pressure exerted on the pool surface can reach a sufficiently high level despite the constraint of surface tension, causing individual droplets of liquid to be released from the pool. Concentrating the beam on or near the surface of the pool increases the radiation pressure exerted in proportion to a given amount of input power. Yet another type of drop-on-demand system is known as thermal inkjet or bubble jet, which produces high-speed droplets. The main components of this type of drop-on-demand system are an ink-filled channel with a nozzle at one end and a heating resistor near the nozzle. The printing signal, representing digital information, generates current pulses in the resistive layer within each ink passage near the orifice or nozzle, causing the nearby ink medium (usually water) to evaporate almost instantaneously, creating bubbles. At the orifice, the ink is pushed out as a propellant droplet as the bubbles expand.

[0144] In a typical piezoelectric inkjet device design, an image is applied by ejecting appropriately colored ink during 4 to 18 rotations (incremental motion) of the substrate, such as an image receiving member or intermediate transfer member, relative to the ink ejection head. That is, there is a small translation of the print head relative to the substrate between each rotation. This technique simplifies the print head design and ensures good droplet alignment with small movements. At the ejection temperature, droplets of liquid ink are ejected from the printing device. When the ink droplets come into contact with the surface of the recording substrate, they rapidly solidify, forming a predetermined pattern of solidified ink droplets.

[0145] In the embodiment, an inkjet printing device may be used. The inkjet printing device includes at least an inkjet print head and a printing area surface from which ink is ejected from the inkjet print head, wherein the height distance between the inkjet print head and the printing area surface is adjustable. In this case, the inkjet print head is adjustable in distance from the printing area surface so as to enable the inkjet print head to move from a first position for normal height printing to a second height distance which is greater than the first height distance (i.e., the distance between the inkjet print head and the printing area surface is greater). The second height distance is not fixed and can be changed as needed for a given print. Furthermore, the second height distance itself can be changed during printing as needed. For example, when an image is formed by the inkjet print head, it may be desirable to adjust the height distance from a first position to a second position, and then, as the image formation progresses, adjust the inkjet print head from the second position to a third position where the distance from the printing area surface is further increased, as needed, to complete the formation of the object.

[0146] In embodiments, the inkjet print head or target stage may be movable in three dimensions, x, y, and z, enabling the formation of objects of any desired size. Furthermore, the three-dimensional object may be formed by passing the inkjet print head over the area multiple times to achieve the desired height and shape of the object. Ink may also be sprayed from multiple different ink nozzles of the inkjet print head towards the same location on the image in a single pass, which can be used to form raised objects. As will be discussed below, in embodiments, each layer of ink may add a height of approximately 1 to approximately 6 mm to the height of the image. Knowing the desired total print height allows for the easy determination of the appropriate number of passes or sprays.

[0147] The controller then controls the inkjet print head to deposit the appropriate amount and / or layer of ink at the image location to obtain an image having the desired print height and overall shape therein. In certain embodiments, the printing system may use additional print heads to construct a target or specific surface topography in a single pass, while utilizing a method of supplying the substrate through the printing system continuously.

[0148] An inkjet printhead can support single-color or full-color printing. In full-color printing, the inkjet printhead typically includes different channels for printing different colors. The inkjet printhead may include four different channel sets, for example, one for each of cyan, magenta, yellow, and black. In such embodiments, the inkjet printhead can either print full-color prints at normal height when the inkjet printhead is set at a minimum distance from the print area surface, or print raised-height prints of any color when the inkjet printhead is at a distance greater than the minimum distance from the print area surface.

[0149] Structured or textured compositions or three-dimensional objects having engineering-designed surface topography prepared herein may be self-supporting parts or objects, rapid prototyping devices, raised structures on a substrate such as a topography map, or other desired objects. Any suitable substrate, recording sheet, or removable support, stage, platform, etc., can be used to deposit three-dimensional objects thereon, and includes plain paper such as Xerox® 4024 paper, Xerox® Image Series paper, Courtland 4024 DP paper, ruled notebook paper, bond paper, etc., silica coated paper such as Sharp Company silica coated paper, JuJo paper, HAMMERMILL LASERPRINT® paper, glossy coated paper such as Xerox® Digital Color Gloss, Sappi Warren Papers LUSTROGLOSS®, inorganic substrates such as transparent materials, fabrics, textiles, plastics, polymer films, metals, and wood, as well as molten or dissolvable substrates such as wax or salt (in the case of removable supports such as self-supporting objects).

[0150] The ink compositions used in the above-described printing apparatus may be prepared by any desired or preferred method. For example, the ink components may be mixed together, then heated to the embodiment's temperature of about 80°C to about 120°C, stirred until a homogeneous ink composition is obtained, and then the ink may be cooled to ambient temperature (typically about 20°C to about 25°C).

[0151] The ink composition generally has a melt viscosity of about 2 to about 30 centipoise at the spray temperature (for example, the spray temperature may be about 50°C to about 120°C, for example, about 60°C to about 110°C, or about 70°C to about 100°C).

[0152] In embodiments, the ink is sprayed at low temperatures, particularly below approximately 110°C, such as approximately 40°C to approximately 110°C, approximately 50°C to approximately 110°C, or approximately 60°C to approximately 90°C. At such low spray temperatures, it may not be effective to use the temperature difference between the sprayed ink and the substrate to which the ink is sprayed, as in conventional methods, to cause a rapid phase change (i.e., from liquid to solid) in the ink. Therefore, a gelling agent may be used to influence the rapid increase in viscosity of the sprayed ink on the substrate. In particular, the sprayed ink droplets can be fixed to a final recording substrate such as paper or a transparent material, or to a receiving substrate such as a transfer drum or belt, which is maintained at a temperature lower than the ink spray temperature of the ink, through the action of a phase change transition in which the ink undergoes a significant viscosity change from a liquid state to a gel state (or semi-solid state).

[0153] In embodiments, the temperature at which the ink forms a gel state is any temperature below the ink ejection temperature, for example, any temperature at least about 5°C lower than the ink ejection temperature. In embodiments, the gel state may be formed at temperatures between about 25°C and about 100°C, such as about 30°C to about 70°C. A rapid and large increase in ink viscosity occurs when the ink cools from the ejection temperature, where it is in a liquid state, to the gel temperature, where it is in a gel state. In embodiments, the viscosity increase is at least 102.5 times the viscosity.

[0154] When the ink is in a gel state, the viscosity of the ink is at least about 1,000 centipoise in one embodiment, at least about 10,000 centipoise in another embodiment, and at least about 100,000 centipoise in yet another embodiment. The viscosity value in the gel state is at least about 103 centipoise in one embodiment, at least about 104.5 centipoise in another embodiment, about 109 centipoise or less in one embodiment, and about 106.5 centipoise or less in another embodiment. The preferred gel phase viscosity can vary depending on the printing process. For example, the highest viscosity is preferred when spraying directly onto porous paper or when using intermediate transfer to minimize the effects of ink bleeding and feathering. On the other hand, less porous substrates such as plastics may result in the use of lower ink viscosity to control dot gain and aggregation of individual ink pixels. The gel viscosity can be controlled by the ink formulation and substrate temperature. A further advantage of the gel state of radiation-curable inks is that as the viscosity increases to approximately 10³–10⁴ centipoise, the diffusion of oxygen in the ink can be reduced, which can lead to a faster curing rate at free radical initiation. In this system, the maximum viscosity achieved exceeds these values ​​(approximately 10⁵–10⁶ centipoise).

[0155] In embodiments, continuous layers of curable ink can be deposited to form objects having selected heights and shapes, for example, objects with heights of approximately 1 to 10,000 micrometers. The continuous layers of curable ink can be deposited on a construction platform or a preceding layer of solidification material to form a three-dimensional object in a layered manner. In embodiments, objects of virtually any design, from micro-scale to macro-scale, can be created, including objects with simple shapes to objects with complex shapes. The inkjet materials and methods herein offer a more advantageous non-contact addition process (as opposed to removal processes such as computer numerical control machining), which provides the ability to incorporate the ability to supply a quantitative amount of the ink material of the present invention to a temporally and spatially precise location.

[0156] In the embodiment, the thickness of the first and each continuous layer of the phase change ink composition may be approximately 0.02 to approximately 6 mm, such as approximately 0.52 to approximately 5.5 mm, approximately 1.02 to approximately 5 mm, approximately 1.52 to approximately 4.5 mm, or approximately 2.02 to approximately 4 mm.

[0157] The gel properties of this material at room temperature prevent the diffusion or migration of printed droplets, allowing for the easy formation of three-dimensional structures. While there are no limitations on the height or overall size of objects that can be created, very large objects may require intermediate curing during the deposition process. Due to the radiation-curable nature of this material, printed objects can be cured by exposure to ultraviolet light at any point during the manufacturing process, resulting in more robust objects with high mechanical strength. "Curing" refers to the increase in molecular weight, such as crosslinking and chain extension, that occurs when the curable compounds in the ink are exposed to chemical radiation.

[0158] In some embodiments, the radiation-curable phase-change inks disclosed herein may cure after each layer of a three-dimensional object has been deposited. In other embodiments, the ink may cure when all layers of the three-dimensional object have been deposited. As described above, printed layers having a thickness of about 0.02 to about 6 mm reduce the curing process required to construct a mechanically stable object and further reduce the need to cure each layer after each deposition.

[0159] The curing of the ink may be affected by exposure of the ink image to chemical rays at any desired or effective wavelength. For example, the wavelength may be about 200 to about 480 nanometers. The exposure to chemical rays may be for any desired or effective period. For example, exposure may be performed for about 0.2 to about 30 seconds, such as about 1 to about 15 seconds.

[0160] In the embodiment, an x, y, z movable substrate, stage, or construction platform is used to create a self-supporting object. That is, the three-dimensional product is a self-supporting, printed or fabricated object, not an image on a substrate, so there is no final substrate. The removable construction platform or support material may be any suitable material, for example, in the embodiment, a non-curable material. Specific examples of suitable non-curable support materials include wax, plastic, metal, wood, and glass.

[0161] In embodiments, a structured surface or three-dimensional object may have both rigid and rubbery components. For example, one component may be printed by using a material containing a curable monomer that imparts a lower or higher room-temperature modulus than the curable monomer of another component of the object. In embodiments, a three-dimensional object may have alternating rigid and flexible layers within a single object, such as a rubbery column with hard caps at its ends. In such examples, a low modulus material may be printed first, followed by a subsequent high modulus material, and then the printed material can be cured. In alternative embodiments, non-curable inks, water-based inks, or high-build viscosity inks may be used in the manner described herein. Alternative embodiments may utilize radiation-cured or non-crosslinked inks, since the ink can be crosslinked or cured without drying, heating, or the use of radiation or external radiation or light sources.

[0162] Figure 1 is a schematic diagram illustrating a process for applying antimicrobial ink to a substrate using a transfer roll process according to an embodiment. This method shows a transfer roll system 100 having a roller 102 with a textured surface 104 that rotates in a rotational direction 106 during operation. As the roller 102 rotates, an ink supply system 108 deposits or coats uncured antimicrobial ink 110 onto the roller 102 to a thickness partially controlled by a doctor blade assembly 112 that contacts the roller 102 or the surface of the ink 110. The substrate 114 moves in the rotational direction 118 and then in the direction 120 through a system that contacts both the upper roller 102 and the lower pressing roller 116 that applies pressure to the opposite side of the substrate 114, thus transferring the uncured antimicrobial ink 110 from the textured roll 102 to the substrate 114. In this manner, the pressure of the textured surface 104 of the roller 102 is applied to the printed surface of the ink 110 before curing. Once the substrate 114 exits the roller, the ink 110 is subjected to a radiation source 122, such as a UV laser or other radiation source, which is suitable for curing the type of ink used. Alternative embodiments may provide a heat source or radiation of a wavelength other than ultraviolet, such as infrared, visible, or a combination thereof. Alternative embodiments may also utilize a UV lamp, UV LED light source, other UV or radiation source, or a combination thereof, which is capable of providing the radiation necessary to initiate curing or crosslinking within the ink. Once exited, the cured ink surface yields a textured ink composition 124 on the surface of the substrate 114.

[0163] Figures 2A–2C are flowcharts illustrating alternative methods for creating printed and textured surfaces having antimicrobial properties according to embodiments. Shown in Figure 2A is a method 200 for preparing a textured antimicrobial surface, which includes designing a template containing texture 206, which can be done according to any digital computer-aided design or physical method known to those skilled in the art. Next, a negative of the template is printed onto a stamping surface 208, which can be done on a variety of suitable substrates, including silicone, polyurethane, or other suitable media useful in transfer printing in such a manner. The stamping substrate is then stamped onto a substrate pre-printed with uncured antimicrobial ink 210, thus imparting a textured or engineered topographic surface to the ink-coated surface as described herein. Finally, a light source or radiation source is provided to cure or crosslink the uncured antimicrobial ink 212 on the surface of the substrate. Figure 2B shows a second process 202 for preparing a textured antimicrobial surface, which includes designing a template containing the texture 214 as described above, and printing the template directly onto a substrate using uncured antimicrobial ink 216 and a suitable printing method as described herein. Finally, this method 202 includes a light source or radiation source provided for curing or crosslinking the uncured antimicrobial ink 218 onto the surface of the substrate. Figure 2C shows a flowchart describing the process shown in more detail in Figure 1. This third process 204 for preparing a textured antimicrobial surface includes applying the uncured antimicrobial ink to a textured roll 220, transferring the uncured antimicrobial ink from the textured roll to a substrate 222, and finally providing a light source or radiation source provided for curing or crosslinking the uncured antimicrobial ink 224 onto the surface of the substrate.

[0164] In alternative embodiments, alternative methods for demonstrating nanostructured surface topography patterning using a curable antimicrobial phase-change ink composition may include directly printing the antimicrobial ink composition onto a substrate or object, creating a stamp on a Mylar substrate via inkjet printing, spreading the antimicrobial phase-change ink composition through a metal mask containing the specific arrangement and shape of the nanostructure, or a combination thereof. Specific method embodiments may be selected depending on the substrate being processed or the available printing equipment. In other embodiments, there may be an additional light source, including a UV laser, prior to patterning to partially cure the ink before it is transferred to the desired substrate. Additional method steps, including the application of a release agent or release coating, such as a fluorocarbon-based release coating or similar material, to the substrate may be used, depending on the application or the material being processed, to facilitate the release of the self-curing antimicrobial phase-change ink composition. [Examples]

[0165] The following embodiments are provided to further define the various types of the disclosure. These embodiments are for illustrative purposes only and are not intended to limit the scope of the disclosure. Unless otherwise indicated, fractions and percentages are in weight.

[0166] UV-curable gelling agent inks can be used in inkjet printing applications or other raised printing applications using various coating methods. These materials consist of radiation-curable monomers and / or oligomers, a photoinitiator package, a reactive wax, and a gelling agent. The raised printing materials exhibit robust spraying at high temperatures (10–15 cPs) and some mechanical stability at ambient substrate temperature (i.e., room temperature) (10⁵–10⁶ cPs). After printing, the markings harden to provide a robust structure. Typical formulations are disclosed below. [Table 1]

[0167] Alternative embodiments of the above formulation may include metal ions, silver nanoparticles, biguanides, N-haramine molecules (e.g., 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC)), and quaternary ammonium compounds (QAC), all of which are biocides commonly used in applications such as wound dressings, lotions, and cleansers. Typical amounts of biocides may range from 0.05% to 2% of the final UV-curable phase-change curable ink composition. Nanoparticles of interest that have shown excellent antimicrobial and biocide activity against a wide range of both Gram-positive and Gram-negative bacteria include copper oxide, silver, gold, zinc oxide, zinc pyrithione, calcium oxide, iron(III) oxide, titanium dioxide, and magnesium oxide.

[0168] While the numerical ranges and parameters described in this disclosure are approximations, the numerical values ​​described in specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors that inevitably arise from the standard deviation observed in each test measurement. Furthermore, all ranges disclosed herein should be understood to encompass any and all subranges contained therein.

[0169] While this teaching is presented in relation to one or more implementations, modifications and / or alterations can be made to the exemplary embodiments without departing from the spirit and scope of the attached claims. In addition, certain features of this teaching may be disclosed in relation to only one of several implementations, but such features may be combined with one or more other features of other implementations as desired and advantageous for any given function or particular function. Furthermore, to the extent that the terms “including,” “includes,” “having,” “has,” and “with,” or their variations thereof, are used in any of the modes for carrying out the invention and in the claims, such terms are intended to be comprehensive in the same manner as the term “comprising.” Furthermore, the term “about” in the discussion and claims herein indicates that the enumerated values ​​may be modified to some extent, provided that the modifications do not result in process or structural incompatibility to the implementations shown. Finally, “exemplary” indicates that the descriptions are used as examples, not that they are ideal.

[0170] It will be understood that variations of those disclosed above, as well as other features and functions, or substitutes thereof, may be combined into many other different systems or applications. Various currently unforeseen or unprecedented substitutes, modifications, variations, or improvements may subsequently be made by those skilled in the art, and these are also intended to be covered by the following claims.

Claims

1. A method for applying an antimicrobial coating to a substrate using a transfer roll system having a roller with an engineered surface topography and a textured surface that rotates in the rotational direction during operation, Uncured phase change ink, Crosslinked monomers, Photoinitiator, Gelling agent, and The process involves depositing or coating an uncured phase-change ink containing an antimicrobial additive onto the roller to a thickness partially controlled by a doctor blade assembly that contacts the roller or the surface of the uncured phase-change ink, by rotating the roller. The roller is rotated to bring the substrate into contact with both the roller on the upper side of the substrate and the pressing roller on the lower side of the substrate that applies pressure to the opposite side of the substrate, thereby moving the substrate in the rotational direction and transferring the uncured phase change ink from the roller to the substrate. Exposing the aforementioned substrate to a UV laser, Including, The surface topography includes protruding shapes having a height of 10 nm to 5000 nm and spaced apart from each other by 1 nm to 5000 nm. A method wherein the antimicrobial additive is present in an amount ranging from 0.01% to 5.00% based on the total weight of the antimicrobial coating.

2. The method according to claim 1, wherein the crosslinked monomer further comprises one or more acrylate monomers in an amount of 4.0% to 80.0% based on the total weight of the antimicrobial coating.

3. The method according to claim 2, wherein the one or more acrylate monomers are selected from the group consisting of a difunctional acrylate monomer, a trifunctional acrylate monomer, a tetrafunctional acrylate monomer, and a pentafunctional acrylate monomer, or a combination thereof.

4. The method according to claim 2, wherein the one or more acrylate monomers are pentafunctional acrylate monomers and difunctional acrylate monomers.

5. The method according to claim 1, wherein the gelling agent is present in an amount ranging from 2.5% to 15.0% based on the total weight of the antimicrobial coating.

6. The method according to claim 1, wherein the gelling agent includes a radiation-curable gelling agent.

7. The method according to claim 1, wherein the antimicrobial additive comprises metal nanoparticles, ionic polymer-metal composite nanoparticles, quaternary ammonium compounds, N-haramine molecules, biguanides, metal oxides, or combinations thereof.

8. The method according to claim 1, wherein the antimicrobial additive comprises silver nanoparticles.

9. The method according to claim 1, wherein the antimicrobial additive comprises a quaternary ammonium compound.

10. The surface topography has an engineering-designed roughness index (ERI) of 5 to 50, and the ERI is Let r be the Wenzel roughness ratio, n be the number of different surface shapes in the surface design, and φ be the area ratio of the tops of the different surface shapes. The method according to claim 1, as defined as:

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