The present disclosure relates to light diffuser materials and in particular, relates to an organic coating for application on a transparent surface to impart at least light diffusion properties to the surface.

BACKGROUND

As is generally known, a lot of applications across industries require light diffusion properties. For example, CN109265595 discloses preparation methods of porous cross-linked polystyrene as light diffusing agent and its subsequent incorporation into a PC matrix material for achieving the light diffusing plate. This volumetric light diffuser material consists of 95-99% of polycarbonate and 1-5% of the light diffusing agent. Further, CN108997729A discloses incorporation of cross-linked microsphere of Polymethyl Methacrylate (PMMA) and cross-linked microsphere of Polystyrene (PS) into the Polycarbonate (PC) matrix for achieving light diffuser action.

CN105601975A discloses utilization of amine resin microspheres as the light diffuser component, which is further incorporated into PC, PS, PMMA, and PET matrix, to obtain the volumetric light diffuser. CN104817828A discloses addition of a light diffuser component to the PET matrix by melt mixing process. CN106432937 discloses a resin substrate and light diffusion agent microspheres dispersing in the resin substrate (used for refrigerator lampshades application), wherein the light diffusion agent microspheres are obtained by copolymerization of at least two different polymer monomers.

EP1213600 relates to a process of producing an optical diffusion film which comprises at least a transparent base layer on a transparent substrate, a layer of transparent microspheres over the transparent base layer and a light absorbing layer over said transparent base layer. The process includes the steps of distributing transparent microspheres in a layer over the transparent base layer so that each transparent microsphere is partly embedded in the transparent base layer; and coating the transparent base layer with a solution layer comprising coloring material that is convertible into fine metal particles and treating the solution layer of coloring material under specified conditions so as thereby to convert the solution layer of coloring material into a layer of fine metal particles that are light absorbable.

CN105601831 relates to a preparation method of amino modified acrylic resin composite microspheres. According to the proposed method, the composite microspheres prepared by the polymerization reaction of prepolymers, which prepared from corresponding monomers, have better haze and photo-diffusion effect than the single acrylic acid microspheres, and thus, can be used as a photo-diffusant in optical films and photo-diffusion plates.

CN101812220 relates to the dispersion of the light diffuser material, made by mixing two cross-linked materials, such as, Polystyrene (PS) and Polymethyl Methacrylate (PMMA) on the film surface at a certain ratio. The cross-linked microspheres of two materials were prepared in a twin-screw extruder. The light diffusion effect is caused by the refraction of light by different types of microspheres owing to their different refractive indexes.

CN109439173 relates to the waterborne polyurethane light diffusion paint. The paint uses organic silicon microsphere suspension as the light diffusion agent ingredients, which was mixed with polyurethane resin material to have a light diffuser coating applied on the inner wall of optical sheets or optical films, especially in LED tubes.

JP2004004598A discloses use of inorganic fillers with resin material to obtain the volumetric light diffuser material. WO2018/219255A1 discloses preparation of light diffusion micro-sphere from porous g-C3N4/Er2O3-MgO composite micro-spheres, and then polymerizing siloxane monomers on the composite micro-spheres in an in-situ manner. EP3052973 A1 discloses Decorative microsphere articles involving with a multilayer stack including organic and inorganic materials.

From the above prior art documents, it is evident that the emphasis is given on the development of volumetric light diffuser where either organic (cross-linked and/or uncross-linked) or inorganic filler materials were used as the prime light diffuser material. To achieve volumetric light diffusing compounds, different melt mixing technologies were used to disperse the light diffuser particles into the polymer matrix. Another way of developing light diffuser is to disperse the light diffuser microsphere material on a transparent sheet or film.

Further, light diffusion can also be generated by applying a coating on any transparent part. Applied coating will have functional properties to generate the light diffusion. CN109439173 discloses one such coating by dispersing the organic silicon microsphere into a waterborne polyurethane matrix to achieve a light diffusion paint. However, the process of manufacturing organic silicon microsphere is complex and costly.

Therefore, there is a need for a material that can be used for enhancing at least light diffuser properties of a surface and is simple to make.

SUMMARY

This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.

The present disclosure relates to an organic coating for application on a transparent surface to impart at least light diffusion properties to the surface. The organic coating includes a base material and a plurality of hollow micro-particle glass spheres incorporated in the base material. A concentration of the hollow micro-particle glass spheres in the base material is varied to control at least one of transparency and haze of the organic coating. The organic coating may also include at least one mineral filler material incorporated in the base material.

At least one of transparency and haze of the organic coating on a transparent surface is controlled by varying a thickness of the coating on the transparent surface. Further, the organic coating is one of a cross-linkable heat or an Ultraviolet (UV) cured cross linkable coating. Therefore, the organic coating of the present disclosure is a hollow inorganic micro-particle and fillers incorporated cross-linkable spray-paintable organic coating having light diffusion properties.

To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

Figure 1 illustrates a schematic view depicting light diffusion through an organic coating applied over a transparent component, according to an embodiment of the present disclosure.

Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present invention. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION OF FIGURES

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.

Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a nonexclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or subsystems or elements or structures or components proceeded by "comprises... a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

It should be understood at the outset that although illustrative implementations of the embodiments of the present disclosure are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.

The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”

The terminology and structure employed herein is for describing, teaching, and illuminating some embodiments and their specific features and elements and does not limit, restrict, or reduce the spirit and scope of the claims or their equivalents.

Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility, and non-obviousness.

Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The present disclosure relates to an organic coating adapted to be applied on a transparent surface to impart at least light diffusion properties to the surface. The organic coating may include, but is not limited to, a base material and a plurality of hollow micro-particle glass spheres incorporated in the base material.

In an embodiment, the base material may include, but is not limited to, an acrylic material, a silicone material, a Polyurethane (PU) material, a polyester material, and an epoxy-based material. For example, epoxy acrylate, polyurethane grafted epoxy, alkyds, silicon acrylate, and polyurethane acrylates may form the base material. The base material may be selected to ensure non-toxicity and easier applicability, while maintaining good adhesion and transparency properties. In an embodiment, a low-pressure system may be used for spray coating of the acrylic coating compared to a urethane coating system.

The hollow micro-particle glass spheres are incorporated in the base material. Further, the hollow micro-particle glass spheres are also referred to as cenosphere, which is a by-product of coal combustion at thermal power plants. Each of the hollow micro-particle glass spheres has a particle size in the range of 5-150 micron. In the defined range of the particle size, the micro-particle glass spheres form a scattered phase, which improves the light diffusion. In fact, in case of size more than the predefined range, the micro-sphere particle may show lesser diffusion effect of the given thickness of the coating.

Further, the concentration of the hollow micro-particle glass spheres in the base material is varied within a range of 0.1 % to 20 % by weight. The deposition of the hollow micro-particle glass spheres over each other improves the diffusion properties of the coating. The defined concentration of micro-particle glass spheres ensures uniform dispersion and spread ability in the base material. In case the concentration is more than the predefined concentration, the micro-particle glass spheres show phase separation from the base material. The concentration of the hollow micro-particle glass spheres in the base material is varied to control at least one of transparency and haze of the organic coating.

In an embodiment, the organic coating may also include at least one mineral filler material incorporated in the base material. The mineral filler material may include, but is not limited to, a silica-based material, an aluminum-based material, a calcium-based material, a zinc-based material, and a titanium-based material. In an embodiment, the concentration of the mineral filler material in the base material is varied within a range of 1-10% by weight. In an embodiment, the hollow micro-particles spheres and the mineral filler may be added to the base material to form the organic coating, through distributive and dispersive blending.

In an embodiment, an overall inorganic filler content in the range of 0-25% is present in the coating, which includes the hollow micro-particle glass spheres and the mineral filler material with remaining composition of the base material.

The hollow micro-particle glass spheres may be selected with the mineral filler material in the coating to obtain better haze property while maintaining higher transparency.

In an embodiment, a surface of each of the plurality of hollow micro-particle glass spheres is modified by a silane coupling agent. The modification may ensure better adhesion with the base material as well as better self-life of the coating without settling down of the filler material.

In an embodiment, the organic coating may be adapted to be one of spray-painted, dip-coated, and spin-coated on the transparent surface. In an embodiment, the organic coating may be adapted to be coated on either one or both surfaces of the transparent surface. Further, at least one of transparency and haze of the organic coating on the transparent surface is controlled by varying a thickness of the coating on the transparent surface.

In an embodiment, the organic coating may be one of a cross-linkable heat or an Ultraviolet (UV) cured cross linkable coating.

As would be gathered, the light diffusion properties can be harnessed from the coating, by application of the coating on any transparent surface, such as plastic. Further, properties, such as transparency and haze can be controlled by varying the thickness of the coating or multiple layer coating or by varying hollow micro-particle spheres concentration in the coating. Further, the mineral filler material in the coating enhances the light diffusion properties of the micro-particle and imparts slight whiteness in the coatings.

Figure 1 illustrates a schematic view depicting light diffusion through the organic coating 102 applied over a transparent component 104, according to an embodiment of the present disclosure. In an embodiment, the transparent component 104 may be formed of a plastic material. As illustrated, the incident light beam falls on the transparent coating matrix 102 and traversed up to the hollow micro-particle glass spheres 106 without any significant changes in the pathways. Further, due to the significant change in refractive index of two mediums, the incident light beam is refracted by the hollow micro-particle glass spheres 106.

In an embodiment, the diffused light is then refracted multiple times by other hollow micro-particle glass spheres 106 encountered across the traversed pathways. Subsequently, the refracted light beams come out from the transparent coating matrix 102 and enter the transparent component 104. While travelling through the transparent component 104, the light beam is further refracted, owing to the change in the refractive index of the coating matrix 102 and the transparent part 104. The refraction of the light beam is dependent on an extent of the change in the refractive index. In an embodiment, the amount of refraction would be better for the hollow micro-particle glass spheres 106 due to presence of air/inert gas entrapped inside the hollow particles 106, for example, due to the significant change in the refractive index.

Therefore, the present disclosure offers the coating 102 that provides light diffusion properties. First, the manufacturing process of inorganic hollow micro-particle spheres is easily available and cost-effective. Further, the coating of the present disclosure offers below-mentioned advantages.
• The properties, such as transparency and haze value can be controlled, for example, by varying a thickness of the coating 102 applied on the transparent component 104.
• Moreover, the need of a new mould or compound for controlling the transmittance and haze value is eliminated.
• The coating 102 can be applied on a wide variety of transparent base materials. Therefore, the present invention has a wide range of application across industries.
• Significant reduction in the thickness of the transparent component 104 can be achieved, owing to the light diffusion properties provided by the coating 102. Accordingly, weight of the transparent component 104 is consequently reduced as well.
• Highly skilled labour is not required for applying the coating 102. Therefore, there is flexibility, at least in terms of efforts required to implement the present invention.
• The present invention offers cost-effective solution, for example, due to the usage of inexpensive material and elimination of the proprietary available materials.
• The coating 102 does not need significant maintenance as well.

Therefore, the organic coating 102 of the present disclosure is easy to make, cost-effective, operation-effective, and involve minimal maintenance.

While specific language has been used to describe the present disclosure, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.

WE CLAIM

1. An organic coating (102) for application on a transparent surface (104) to impart at least light diffusion properties to the surface (104), the organic coating (102) comprising:
a base material; and
a plurality of hollow micro-particle glass spheres (106) incorporated in the base material, wherein a concentration of the hollow micro-particle glass spheres (106) in the base material is varied to control at least one of transparency and haze of the organic coating (102).

2. The organic coating (102) as claimed in claim 1, wherein the base material comprising at least one of an acrylic material, a silicone material, a Polyurethane (PU) material, a polyester material, and an epoxy-based material.

3. The organic coating (102) as claimed in claim 1, wherein the concentration of the plurality of the hollow micro-particle glass spheres (106) in the base material is varied within a range of 0.1 % to 20 % by weight.

4. The organic coating (102) as claimed in claim 1, wherein each of the hollow micro-particle glass spheres (106) has a particle size in the range of 5-150 micron.

5. The organic coating (102) as claimed in claim 1, wherein a surface of each of the plurality of hollow micro-particle glass spheres (106) is modified by a silane coupling agent.

6. The organic coating (102) as claimed in claim 1, comprising at least one mineral filler material incorporated in the base material.

7. The organic coating (102) as claimed in claim 6, wherein the at least one mineral filler material is one of a silica-based material, an aluminium-based material, a calcium-based material, a zinc-based material, and a titanium-based material.

8. The organic coating (102) as claimed in claim 6, wherein the concentration of the at least one mineral filler material in the base material is varied within a range of 1-10% by weight.

9. The organic coating (102) as claimed in claim 6, wherein the plurality of hollow micro-particles spheres (106) and the at least one mineral filler are added to the base material through distributive and dispersive blending.

10. The organic coating (102) as claimed in claim 1, wherein the organic coating is adapted to be one of spray-painted, dip-coated, and spin-coated on the transparent surface.

11. The organic coating (102) as claimed in claim 1, where in the organic coating is adapted to be coated on either one or both of the surfaces of the transparent surface.

12. The organic coating (102) as claimed in claim 1, wherein at least one of transparency and haze of the organic coating on the transparent surface is controlled by varying a thickness of the coating on the transparent surface (104).

13. The organic coating (102) as claimed in claim 1, wherein the organic coating is one of a cross-linkable heat or an Ultraviolet (UV) cured cross linkable coating.