WO2019081959A1

WO2019081959A1 - Antibacterial powder coating

Info

Publication number: WO2019081959A1
Application number: PCT/IB2017/056564
Authority: WO
Inventors: Mahdi RAHMANI
Original assignee: Rahmani Mahdi
Priority date: 2017-10-23
Filing date: 2017-10-23
Publication date: 2019-05-02
Also published as: CA3075056A1

Abstract

An antibacterial powder coating composition is disclosed that may include a polymer resin, a curing agent, a pigment, a nanosilver-coated filler, and zinc oxide nanoparticles.

Description

ANTIBACTERIAL POWDER COATING

TECHNICAL FIELD

[0001] The present disclosure generally relates to powder coating compositions and methods for synthesizing the same, particularly to a powder coating composition with antibacterial properties and methods for synthesizing the same.

BACKGROUND ART

[0002] Powder coating compositions are solid compositions that generally comprise a solid film-forming resin, a curing agent, usually with one or more pigments and, optionally, one or more performance additives such as plasticizers, stabilizers, flow aids and extenders. The powder coating compositions may be applied to a substrate by different methods, such as electrostatic spraying. Apart from the need for specific particle size distributions for powder coating compositions based on particular applications, there is a need in the art for adding other properties to these powder coating compositions, such as antibacterial and/or anticorrosive properties.

SUMMARY OF THE DISCLOSURE

[0003] This summary is intended to provide an overview of the subject matter of this patent, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of this patent may be ascertained from the claims set forth below in view of the detailed description below and the drawings. [0004] In one general aspect, the present disclosure is directed to an antibacterial coating composition that may include a polymer resin, a curing agent, a pigment, a filler that may be coated with silver nanoparticles, and zinc oxide nanoparticles.

[0005] According to some implementations, the polymer resin may be present in an amount less than 60 wt. % of the total antibacterial powder composition; the curing agent may be present with an amount between 3% and 9% of the weight of the polymer resin present in the antibacterial powder composition; the pigment may be present in an amount less than 5 wt. % of the total antibacterial powder composition; the filler coated with silver nanoparticles may be present in an amount between 20 and 30 wt. % of the total antibacterial powder composition; and the zinc oxide nanoparticles may be present in an amount between 1 and 2 wt. % of the total antibacterial powder composition.

[0006] According to some implementations, the filler may include BaS0₄. In other implementations, the antibacterial powder composition may further include a degassing agent in an amount less than 0.5 wt. % of the total antibacterial powder composition.

[0007] In some implementations, the polymer resin may be selected from the group consisting of a polyester resin, an epoxy resin, and mixtures thereof. In other implementations, the curing agent may include a polyepoxide curing agent.

[0008] In another general aspect, the present disclosure is directed to an antibacterial coating composition that may include a polymer resin, a curing agent, a pigment that may be coated with silver nanoparticles, and zinc oxide nanoparticles.

[0009] According to some implementations, the polymer resin may be present in an amount less than 60 wt. % of the total antibacterial powder composition; the curing agent may be present with an amount between 3% and 9% of the weight of the polymer resin present in the antibacterial powder composition; the pigment may be present in an amount less than 30 wt. % of the total antibacterial powder composition; and the zinc oxide nanoparticles may be present in an amount between 1 and 2 wt. % of the total antibacterial powder composition.

[0010] In some implementations, the antibacterial powder coating composition may further include a filler in an amount of less than 10 wt. % of the total antibacterial powder composition.

[0011] In some implementations, the pigment may include T1O2. In other implementations, the antibacterial powder coating composition may further include a degassing agent in an amount less than 0.5 wt. % of the total antibacterial powder composition.

[0012] According to yet another general aspect, the present disclosure is directed to a method for synthesizing an antibacterial powder coating composition that may include: coating a filler with silver nanoparticles by first mixing the filler with a silver nano-colloid and then Calcinating the filler and the silver nano-colloid mixture to obtain a nanosilver-coated filler, preparing a powder coating premix by dry -mixing a polymer resin, a curing agent, a pigment, the nanosilver-coated filler, and zinc oxide nanoparticles, preparing a powder coating precursor by extruding the powder coating premix in a twin-screw extruder, cooling the powder coating precursor to a cooled powder coating precursor, flaking the cooled powder coating precursor to powder coating precursor flakes and fine grinding the powder coating precursor flakes into a fine powder coating.

[0013] According to some implementations, coating a filler with silver nanoparticles may include mixing the filler with a silver nano-colloid to obtain a mixture with silver nano-colloid being present in the mixture in an amount of at least 2000 ppm. [0014] According to some implementations, coating a filler with silver nanoparticles may include mixing the filler with a silver nano-colloid to obtain a mixture with silver nano-colloid being present in the mixture in an amount between 2000 ppm and 7000 ppm.

[0015] According to an implementation, preparing the powder coating premix may include dry-mixing a polymer resin in an amount less than 60 wt. % of the powder coating premix, a curing agent in an amount between 3% and 9% of the weight of the polymer resin present in the powder coating premix, a pigment in an amount less than 5 wt. % of the powder coating premix, the nanosilver-coated filler in an amount between 20 and 30 wt. % of the powder coating premix, and zin oxide nanoparticles in an amount between 1 and 2 wt. % of the powder coating premix.

[0016] According to yet another general aspect, the present disclosure is directed to a method for synthesizing an antibacterial powder coating composition that may include: coating a pigment with silver nanoparticles by first mixing the pigment with a silver nano-colloid and then Calcinating the pigment and the silver nano-colloid mixture to obtain a nanosilver-coated pigment, preparing a powder coating premix by dry-mixing a polymer resin, a curing agent, the nanosilver-coated pigment, and zinc oxide nanoparticles, preparing a powder coating precursor by extruding the powder coating premix in a twin-screw extruder, cooling the powder coating precursor to a cooled powder coating precursor, flaking the cooled powder coating precursor to powder coating precursor flakes, and fine grinding the powder coating precursor flakes into a fine powder coating.

[0017] According to some implementations, preparing the powder coating premix may include dry-mixing a polymer resin in an amount less than 60 wt. % of the powder coating premix, a curing agent in an amount between 3% and 9% of the weight of the polymer resin present in the powder coating premix, the nanosilver-coated pigment in an amount less than 30 wt. % of the powder coating premix, and zin oxide nanoparticles in an amount between 1 and 2 wt. % of the powder coating premix. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

[0019] FIG. 1 illustrates a method for synthesizing antibacterial powder coating compositions, according to one or more implementations of the present disclosure.

[0020] FIG. 2 illustrates a twin screw extruder, according to one exemplary embodiment of the present disclosure.

[0021] FIG. 3 illustrates the screw shaft according to an exemplary embodiment of the present disclosure.

[0022] FIG. 4 illustrates an exemplary embodiment of a kneading disc.

[0023] FIG. 5 illustrates a front view schematic representation of the two side by side screw shafts fitted inside a barrel or tube of the extruder, according to one implementation of the present disclosure.

[0024] FIG. 6 illustrates a schematic representation of a manufacturing system, according to one implementation of the present disclosure.

[0025] FIG. 7 illustrates a method for synthesizing antibacterial powder coating compositions, according to one or more implementations of the present disclosure. [0026] FIG. 8 is a scanning electron microscope (SEM) image of nanosilver-coated T1O2, according to an exemplary embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS

[0027] In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

[0028] Disclosed herein is an antibacterial powder coating composition and a method for synthesizing the antibacterial powder coating composition. The antibacterial powder coating composition may include one or more of components including a polyester resin, a curing agent, a pigment, and optionally a filler. The antibacterial powder coating composition may further include an antibacterial agent including silver nanoparticles and zinc oxide nanoparticles. The antibacterial agent may be coated on either the filler or the pigment (in case of white pigments) or alternatively the antibacterial agent may be directly pre-mixed with other components present in the powder coating composition. Antibacterial properties of silver nanoparticles in combination with photocatalytic properties of zinc oxide allow for synthesizing an antibacterial powder coating that may be utilized as a final coating on different industrial surfaces in order to make the surfaces antibacterial.

[0029] FIG. 1 illustrates a method 100 for synthesizing antibacterial powder coating compositions, according to one or more implementations of the present disclosure. Referring to FIG. 1, in one implementation, method 100 may include a first step 101 of coating a filler with silver nanoparticles to obtain a nanosilver-coated filler; a second step 102 of preparing a powder coating premix by dry-mixing a polymer resin, a curing agent, a pigment, the nanosilver-coated filler, and zinc oxide (ZnO) nanoparticles; a third step 103 of extruding the powder coating premix in an extruder to obtain a powder coating precursor; an optional fourth step 104 of cooling the powder coating precursor; an optional fifth step 105 of flaking the cooled powder coating precursor to obtain powder coating precursor flakes; and an optional sixth step 106 of fine grinding the powder coating precursor flakes into a fine powder coating with a narrow and well-defined particle size distribution.

[0030] Referring to FIG. 1, in an implementation, in step 101 of method 100, coating the filler with silver nanoparticles may include mixing the filler with a silver nano-colloid to obtain a homogeneous mixture and then Calcinating the homogeneous mixture at a predetermined temperature to obtain the nanosilver-coated filler. For example, according to some implementations, the filler may be mixed with the silver nano-colloid in a mixer to obtain the homogeneous mixture. Mixing may be carried out for a duration of, for example, between 25 and 45 minutes. In an implementation, concentration of silver nano-colloid in the homogeneous mixture may be at least 4000 ppm. According to some implementations, Calcinating the homogeneous mixture may include heating the homogeneous mixture at a temperature of, for example between 60 and 80 °C for a duration of, for example between 25 and 40 minutes. In an exemplary embodiment, the filler may be BaS0₄.

[0031] Referring to FIG. 1, in some implementations, in step 102 of method 100, preparing a powder coating premix may include weighing individual ingredients into a blender and dry- mixing the polymer resin, the curing agent, the pigment, the nanosilver-coated filler, and the zinc oxide (ZnO) nanoparticles. In some implementations, the powder coating premix may further include a degassing agent.

[0032] According to some implementations, the polymer resin may be a polyester resin, an epoxy resin or a mixture of a polyester resin and an epoxy resin. The curing agent may be an agent that has amine or amide groups, for example a polyepoxide curing agent such as triglycidyl isocyanurate (TGIC). The degassing agent may be benzoin, which is utilized to ensure a flat surface without holes on a final coated surface. The pigment may optionally be mixed in the powder coating premix to add a desired color to the final coating. The powder coating premix may be obtained by dry-mixing predetermined amounts of one or more of the polymer resin, the curing agent, optionally the degassing agent, the pigment, the nanosilver- coated filler, and ZnO nanoparticles. ZnO nanoparticles exhibit photocatalytic antibacterial properties that may help improve the antibacterial properties of the powder coating composition, according to one or more exemplary embodiments of the present disclosure. In one exemplary embodiment, the dry-mixing may be carried out in a tumbling mixer for a duration of, for example between 30 and 60 minutes at room temperature.

[0033] With further reference to FIG. 1, according to some implementations, in step 102 of method 100, the polymer resin may be present in the powder coating premix in an amount less than 60 wt. % based on the weight of the powder coating premix; the curing agent may be added with an amount between for example 3 and 9 percent of the weight of the polymer resin present in the powder coating premix; the degassing agent may be present in the powder coating premix in an amount less than 0.5 wt. % based on the weight of the powder coating premix; the pigment may be present in the powder coating premix in an amount less than 5 wt. % based on the weight of the powder coating premix; the nanosilver-coated filler may be present in the powder coating premix in an amount between 20 and 30 wt. % based on the weight of the powder coating premix; ZnO nanoparticles may be present in the powder coating premix in an amount between 1 and 2 wt. % based on the weight of the powder coating premix; and optionally other additives such as flow control agents may be added to the first mixture. In an example, such flow control agents, which enhance the composition's melt-flow properties and assist in eliminating surface defects, typically include acrylics and fluorine based polymers.

[0034] Referring to FIG. 1, with respect to third step 103, the powder coating premix may be extruded in a twin screw extruder, where the powder coating premix may be melted and different ingredients may be dispersed within the resin using shear force of the screws. For example, in an implementation, the first mixture may be extruded in a twin screw extruder with two co-rotating and intermeshing screws that may help improve the dispersion of other ingredients in the resin as the resin melts.

[0035] FIG. 2 illustrates a twin screw extruder 200, according to one exemplary embodiment of the present disclosure. Twin screw extruder 200 may include a tube or barrel within which a pair of screw shafts (only screw shaft 204 is visible in FIG. 2) are fitted with a number of different screw elements. The extruder 200 may further include a number of thermal sections 201, 202, and 203 which are disposed axially one after the other. The screw shafts are driven by a driving mechanism 205 that may include a gearbox and a motor. FIG. 3 illustrates the screw shaft 204 according to an exemplary embodiment of the present disclosure. Screw shaft 204 may at least include a conveying screw section 301 and a kneading section 302. Kneading section 302 may include a number of kneading discs. FIG. 4 illustrates an exemplary embodiment of a kneading disc 400 that may include a central cylindrical region 401 defining a bore that has splines 402 for mounting the kneading disk 400 on the screw shaft 204 (labeled in FIGs. 2 and 3) and the screw shaft 204 may have corresponding splines so that the kneading disc 400 does not rotate relative to the screw shaft 204 but with the screw shaft 204.

[0036] Referring to FIG. 3, in one implementation, each kneading disc in the kneading section 302 may be mounted on the screw shaft 204 by a relative 30° offset rotation from one kneading disc to the next. FIG. 5 illustrates a front view schematic representation of the two side by side screw shafts 204 and 204' fitted inside a barrel or tube 501 of the extruder, which are intermeshing and co-rotating. In an example, the arrangement of the kneading discs on each screw shaft may be such that the kneading discs on screw shaft 204 are at a 90° orientation to the kneading discs on screw shaft 204'.

[0037] With further reference to FIGs. 2 and 3, in an implementation, thermal section 201 may function as a feeding zone and the powder coating premix may be fed into the thermal section 201. The conveying screw section 301 of each of the two side by side screw shafts is placed inside thermal section 201. In an example, thermal section 201 may have a temperature of approximately 80 °C. The powder coating premix may be partially melted in thermal section 201 and it may be conveyed by the conveying screws to thermal section 202 that may function as a melting zone. Thermal section 202 may have a temperature of approximately 110 °C and it encompasses a part of the kneading section 302 of each screw shaft. In thermal section 202, the powder coating premix is melted and kneaded by the kneading discs of the two side by side screw shafts and the molten coating premix is pushed toward thermal zone 203 that functions as a distribution zone. The molten premix is further kneaded in thermal section 203. Thermal section 203 may have a temperature of approximately 80 °C. The extruded molten premix which is referred to hereinafter as powder coating precursor may then be discharged from the extruder. [0038] Referring back to FIG. 1, once the powder coating premix is extruded in the twin extruder, the powder coating precursor may proceed to fourth step 104 of method 100, where the powder coating precursor may be cooled. In an example, the powder coating precursor may be fed to a cool roller where the precursor is cooled and formed into a thin film.

[0039] With respect to the fifth step 105, cooled powder coating precursor may then be flaked to obtain powder coating precursor flakes. Flaked precursor may then proceed to sixth step 106, where the flakes are ground into a fine powder coating in a grinder in order to obtain the antibacterial powder coating pursuant to the teachings of the present disclosure.

[0040] FIG. 6 illustrates a schematic representation of a manufacturing system 600 that may be configured as an implementation of method 100 of FIG. 1. Referring to FIG. 6, system 600 may include a pre-mixing unit 601, where the powder coating premix may be prepared by weighing individual ingredients into a blender 602. In an example, the blender 602 may be a tumbling mixer that may be utilized for dry-mixing the polymer resin, the curing agent, the pigment, the nanosilver-coated filler, the zinc oxide (ZnO) nanoparticles, and optionally the degassing agent in order to obtain the powder coating premix. The powder coating premix may then be fed into an extrusion unit 603 that may be, in an exemplary embodiment, a twin screw extruder 200 as was described in more detail in connection with FIGs. 2 to 5. The powder coating premix undergoes melt mixing in the extruder and all ingredients, especially the antibacterial agents may be thoroughly dispersed into the resin. Once the powder coating premix is extruded, a molten premix or the powder coating precursor is obtained. The powder coating precursor may then be discharged through the extruder die into a cool rolling unit 604, where the precursor is passed through two cooled rollers to make a thin sheet. The thin sheet is then passed via a conveyor belt 605 into a flaking unit 606, where the brittle sheet is broken into flakes. The flakes are then ground in a fine grinding unit 607 into a fine powder coating.

[0041] FIG. 7 illustrates a method 700 for synthesizing antibacterial powder coating compositions, according to one or more implementations of the present disclosure. Referring to FIG. 7, in one implementation, method 700 may include a first step 701 of coating a pigment with silver nanoparticles to obtain a nanosilver-coated pigment; a second step 702 of preparing a powder coating premix by dry-mixing a polymer resin, a curing agent, a filler, the nanosilver- coated pigment, and zinc oxide (ZnO) nanoparticles; third step 103 of extruding the powder coating premix in an extruder to obtain a powder coating precursor; optional fourth step 104 of cooling the powder coating precursor; optional fifth step 105 of flaking the cooled powder coating precursor to obtain powder coating precursor flakes; and optional sixth step 106 of fine grinding the powder coating precursor flakes into a fine powder coating with a narrow and well-defined particle size distribution.

[0042] Referring to FIG. 7, in an implementation, in step 701 of method 700, coating the pigment with silver nanoparticles may include mixing the pigment with a silver nano-colloid to obtain a homogeneous mixture and then Calcinating the homogeneous mixture at a predetermined temperature to obtain the nanosilver-coated pigment. For example, according to some implementations, the pigment may be mixed with the silver nano-colloid in a mixer to obtain the homogeneous mixture. Mixing may be carried out for a duration of, for example, between 25 and 45 minutes. In an implementation, concentration of silver nano-colloid in the homogeneous mixture may be at least 4000 ppm. According to some implementations, Calcinating the homogeneous mixture may include heating the homogeneous mixture at a temperature of, for example between 60 and 80 °C for a duration of, for example between 25 and 40 minutes. In an exemplary embodiment, the pigment may be T1O2.

[0043] With further reference to FIG. 7, according to some implementations, in step 702 of method 700, the polymer resin may be present in the powder coating premix in an amount less than 60 wt. % based on the weight of the powder coating premix; the curing agent may be added with an amount between for example 3 and 9 percent of the weight of the polymer resin present in the powder coating premix; the degassing agent may be present in the powder coating premix in an amount less than 0.5 wt. % based on the weight of the powder coating premix; the nanosilver-coated pigment may be present in the powder coating premix in an amount less than 30 wt. % based on the weight of the powder coating premix; the filler may be present in the powder coating premix in an amount less than 10 wt. % based on the weight of the powder coating premix; ZnO nanoparticles may be present in the powder coating premix in an amount between 1 and 2 wt. % based on the weight of the powder coating premix; and optionally other additives such as flow control agents may be added to the first mixture. In an example, such flow control agents, which enhance the composition's melt-flow properties and assist in eliminating surface defects, typically include acrylics and fluorine based polymers.

[0044] Referring to FIG. 7, once the powder coating premix is prepared, method 700 may proceed to steps 103, 104, 105, and 106 as was described in more detail in connection with method 100 of FIG. 1. For purposes of clarification, the antibacterial powder coating of the present disclosure may be synthesized by either method 100 of FIG. 1 or method 700 of FIG. 7. For white antibacterial powder coatings, where the pigment is a white or semi -white pigment such as Ti0₂, method 700 may be utilized, where Ti0₂ is coated with silver nanoparticles as was described in detail in connection with step 701 of method 700. FIG. 8 is a scanning electron microscope (SEM) image of nanosilver-coated T1O2 where nanosilver particles 800 are clearly shown to be deposited onto the T1O2 particles. It should be understood that method 100 of FIG. 1 may as well be utilized for synthesizing white antibacterial powder coatings. For non-white antibacterial powder coatings, where the pigment is not a white or semi-white pigment, method 100 of FIG. 1 may be utilized, where instead of the pigment, the filler is coated with silver nanoparticles. It should also be understood that method 700 of FIG. 7 may as well be utilized for synthesizing non-white antibacterial powder coatings.

EXAMPLE

[0045] In this example, an antibacterial powder coating composition was synthesized pursuant to the teachings of the present disclosure. In the antibacterial powder coating composition of the present example, the polyester resin was present in an amount of 60 wt. % based on the weight of the composition; TGIC as the curing agent was present in an amount of 6.6 wt. % based on the weight of the composition; benzoin as the degassing agent was present in an amount of 0.5 wt. % based on the weight of the composition; T1O2 as the pigment was present in an amount of 12 wt. % based on the weight of the composition; nanosilver-coated BaS0₄ as the filler in an amount of 20 wt. % based on the weight of the composition; ZnO nanoparticles were present in an amount of 2 wt. % based on the weight of the composition; and the composition may further include other additives such as flow control agents with an amount of 0.8 wt. % based on the weight of the composition. In order to coat the BaS0₄ with nanosilver, a silver nano-colloid was mixed with BaS0₄ in order to obtain a homogeneous mixture containing 4000 ppm of silver nano-colloid and then the homogeneous mixture was Calcinated. A twin screw extruder with a screw shaft length of 40 cm having a conveying screw section with a length of 18 cm and a kneading section with a length of 22 cm that had 42 kneading discs was utilized to ensure thorough mixing of the nano additives into the polymer resin. The extruder had a rotational speed of 1200 rpm. The extruded precursor was then cooled and flaked and a grinder was used to grind the flakes into a fine powder with an average particle size of less than 60 micrometer. The obtained powder coating was then used in an electrostatic spray process in which the obtained antibacterial coating particles were electrostatically charged by a spray gun and directed onto an earthed substrate. The substrate was then heated in an oven with a temperature between 180 and 200 °C for 10 to 12 minutes to obtain a substrate with antibacterial properties. TABLE 1 sets forth the results of antibacterial properties test performed on a coated sample with the antibacterial powder coating of the present example. Suspensions of two different bacteria of E.coli and S. aureus with similar concentrations of 1.5 x 10⁶ cfu/ml were prepared. A sample coated with the antibacterial powder coating of the present example was exposed to these suspensions for 24 hours. Then the bacteria count was obtained after the 24-hour exposure. A control sample without the antibacterial coating was also exposed for a 24-hour period with the bacteria suspensions. The bacteria count for the control sample is also reported in TABLE 1. The results clearly show the antibacterial effect of the powder coating of the present example.

[0046] TABLE 1. Antibacterial Properties Test Results

[0047] While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.

[0048] Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

[0049] The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 101, 102, or 103 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.

[0050] Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.

[0051] It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a" or "an" does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0052] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various implementations. This is for purposes of streamlining the disclosure, and is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed implementation. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

[0053] While various implementations have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more implementations and implementations are possible that are within the scope of the implementations. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any implementation may be used in combination with or substituted for any other feature or element in any other implementation unless specifically restricted. Therefore, it will be understood that any of the features shown and/or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the implementations are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.

Claims

What is claimed is:

1. An antibacterial powder coating composition, comprising:

a polymer resin;

a curing agent;

a pigment;

a filler, the filler coated with silver nanoparticles; and

zinc oxide nanoparticles.

2. The antibacterial powder coating composition of claim 1, wherein the polymer resin being present in an amount less than 60 wt. % of the total antibacterial powder composition, the curing agent being present with an amount between 3% and 9% of the weight of the polymer resin present in the antibacterial powder composition, the pigment being present in an amount less than 5 wt. % of the total antibacterial powder composition, the filler coated with silver nanoparticles being present in an amount between 20 and 30 wt. % of the total antibacterial powder composition, and the zinc oxide nanoparticles being present in an amount between 1 and 2 wt. % of the total antibacterial powder composition.

3. The antibacterial powder coating composition of claim 2, wherein the filler includes BaS0₄.

4. The antibacterial powder coating composition of claim 2, further comprising a degassing agent in an amount less than 0.5 wt. % of the total antibacterial powder composition.

5. The antibacterial powder coating composition of claim 1, wherein the polymer resin is selected from the group consisting of a polyester resin, an epoxy resin, and mixtures thereof.

6. The antibacterial powder coating composition of claim 4, wherein the curing agent includes a polyepoxide curing agent.

7. An antibacterial powder coating composition, comprising:

a polymer resin;

a curing agent;

a pigment, the pigment coated with silver nanoparticles; and

zinc oxide nanoparticles.

8. The antibacterial powder composition of claim 7, wherein the polymer resin being present in an amount less than 60 wt. % of the total antibacterial powder composition, the curing agent being present with an amount between 3% and 9% of the weight of the polymer resin present in the antibacterial powder composition, the pigment being present in an amount less than 30 wt. % of the total antibacterial powder composition, and the zinc oxide nanoparticles being present in an amount between 1 and 2 wt. % of the total antibacterial powder composition.

9. The antibacterial powder coating composition of claim 8, further comprising a filler in an amount of less than 10 wt. % of the total antibacterial powder composition.

10. The antibacterial powder coating composition of claim 7, wherein the pigment include T1O2.

11. The antibacterial powder coating composition of claim 7, further comprising a degassing agent in an amount less than 0.5 wt. % of the total antibacterial powder composition.

12. A method for synthesizing an antibacterial powder coating composition, the method comprising:

coating a filler with silver nanoparticles by first mixing the filler with a silver nano-colloid and then Calcinating the filler and the silver nano-colloid mixture to obtain a nanosilver-coated filler;

preparing a powder coating premix by dry-mixing a polymer resin, a curing agent, a pigment, the nanosilver-coated filler, and zinc oxide nanoparticles;

preparing a powder coating precursor by extruding the powder coating premix in a twin-screw extruder;

cooling the powder coating precursor to a cooled powder coating precursor;

flaking the cooled powder coating precursor to powder coating precursor flakes; and

fine grinding the powder coating precursor flakes into a fine powder coating.

13. The method of claim 12, wherein silver nano-colloid being present in the filler and silver nano-colloid mixture in an amount of at least 2000 ppm.

14. The method of claim 12, wherein silver nano-colloid being present in the filler and silver nano-colloid mixture in an amount between 4000 ppm and 7000 ppm.

15. The method of claim 12, wherein preparing the powder coating premix comprises dry-mixing a polymer resin in an amount less than 60 wt. % of the powder coating premix, a curing agent in an amount between 3% and 9% of the weight of the polymer resin present in the powder coating premix, a pigment in an amount less than 5 wt. % of the powder coating premix, the nanosilver-coated filler in an amount between 20 and 30 wt. % of the powder coating premix, and zin oxide nanoparticles in an amount between 1 and 2 wt. % of the powder coating premix.

16. The method according to claim 12, wherein the filler includes BaS0₄.

17. A method for synthesizing an antibacterial powder coating composition, the method comprising:

coating a pigment with silver nanoparticles by first mixing the pigment with a silver nano-colloid and then Calcinating the pigment and the silver nano-colloid mixture to obtain a nanosilver-coated filler;

preparing a powder coating premix by dry-mixing a polymer resin, a curing agent, the nanosilver-coated pigment, and zinc oxide nanoparticles;

cooling the powder coating precursor to a cooled powder coating precursor; flaking the cooled powder coating precursor to powder coating precursor flakes; and

fine grinding the powder coating precursor flakes into a fine powder coating.

18. The method of claim 17, wherein preparing the powder coating premix comprises dry-mixing a polymer resin in an amount less than 60 wt. % of the powder coating premix, a curing agent in an amount between 3% and 9% of the weight of the polymer resin present in the powder coating premix, the nanosilver-coated pigment in an amount less than 30 wt. % of the powder coating premix, and zin oxide nanoparticles in an amount between 1 and 2 wt. % of the powder coating premix.

19. The method of claim 17, wherein the pigment includes T1O2.