Retroreflective resin powder, manufacturing method therefor, and coating method using same

Abstract

The present invention relates to a retroreflective resin powder and, more specifically, to: a retroreflective resin powder manufactured by combining encapsulated glass beads and a thermoplastic resin; a manufacturing method therefor; and a coating method using same. The retroreflective resin powder of the present invention comprises encapsulated glass beads and a thermoplastic resin, wherein the encapsulated glass beads have a particle size of 30-60 μm and a refractive index of 2.2 or higher, and the thermoplastic resin includes at least one of polyester, polyurethane and acrylic resin.

Description

Retroreflective resin powder, method of manufacturing the same, and coating method using the same

[0001] The present invention relates to a retroreflective resin powder, and more specifically, to a retroreflective resin powder manufactured by combining a sealed glass bead and a thermoplastic resin, a method for manufacturing the same, and a coating method using the same.

[0002] Technologies that enhance visibility in nighttime or low-light environments play a crucial role in various industries, including traffic safety, construction materials, and advertising. One such technology, retroreflective technology, significantly improves nighttime visibility by reflecting light back in its original direction.

[0003] Retroreflective technology is widely used in road signs, vehicle exteriors, pedestrian protection equipment, and building exteriors. Conventional retroreflective technology is primarily provided in film form, which is widely used due to its simple and convenient application process. However, retroreflective materials in film form have the following limitations. First, it is difficult to apply to curved or complex surfaces. This is due to the limited physical properties of the film, and there is a high probability of adhesion failure when applied to curved surfaces. Second, the durability of the film is limited. When exposed to outdoor environments for extended periods, problems such as peeling or degradation of retroreflective performance occur. Third, film forms are difficult to recycle and must be treated as waste after use, making them unenvironmentally friendly.

[0004] Furthermore, retroreflective materials provided in the form of liquid paints have been proposed as an alternative to compensate for the limitations of film forms. Liquid paints can be applied to various surfaces and exhibit consistent retroreflective properties after curing. However, liquid paints have the following problems. First, since liquid paints use organic solvents during the application process, volatile organic compounds (VOCs) are released, having a negative impact on the environment. Second, the application process is complex and requires skilled technicians. Third, there is a possibility of uneven coating occurring during the curing process, which can lead to a degradation of retroreflective performance.

[0005] Powder coating technology has recently been attracting attention. Powder coating is a method in which powder-form paint is evenly applied to a surface via electrical charging and then fixed by heating. This technology is environmentally friendly and offers excellent workability as it produces no VOC emissions and forms a uniform coating. However, retroreflective materials for powder coating are currently available in limited quantities, and it is difficult to effectively exhibit retroreflective properties with existing powder paints. Therefore, there is a need for the development of new materials that are provided in powder form and possess retroreflective properties.

[0006] (Patent Document 1) Korean Published Patent No. 10-2024-0009966

[0007] In order to solve the problems of the conventional technology described above, the retroreflective resin powder of the present invention, the method for manufacturing the same, and the coating method using the same are intended to provide a retroreflective resin powder, a method for manufacturing the same, and a coating method using the same, which includes a sealed glass bead and a thermoplastic resin, and provides excellent coatability and durability along with a retroreflective effect.

[0008] The technical problems that the invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the invention belongs from the description below.

[0009] The retroreflective resin powder of the present invention comprises a sealed glass bead and a thermoplastic resin, wherein the sealed glass bead has a particle size of 30 to 60 μm and a refractive index of 2.2 or higher, and the thermoplastic resin comprises at least one of polyester, polyurethane, and acrylic resin.

[0010] In addition, the retroreflective resin powder of the present invention is characterized by being additionally applied on a coating layer containing a metallic or pearl pigment applied as a primary coating layer.

[0011] In addition, the method for manufacturing a retroreflective resin powder according to the present invention is characterized by comprising: a first step of crushing a resin; a second step of adding a sealed glass bead to the crushed resin and mixing it; a third step of extruding the mixed mixture to solidify it; a fourth step of cooling the solidified mixture; and a fifth step of crushing the cooled material.

[0012] In addition, the method for manufacturing a retroreflective resin powder according to the present invention is characterized in that the resin is a thermoplastic resin.

[0013] In addition, the retroreflective resin powder coating method of the present invention is characterized by comprising: a) a step of preparing the surface of a workpiece; b) a step of applying and curing a first coating layer containing a metallic or pearl pigment to the surface of the workpiece; c) a step of applying a second coating layer on the first coating layer using retroreflective resin powder; and d) a step of curing the second coating layer.

[0014] The retroreflective resin powder according to the present invention comprises sealed glass beads and a thermoplastic resin, and can exhibit excellent retroreflective performance. In particular, the sealed glass beads have optimized refractive index and particle size, thereby providing a stable retroreflective effect even in the presence of a water film or transparent coating.

[0015] In addition, since the retroreflective resin powder of the present invention is provided in powder form, it can be easily applied to various surfaces including curved or complex shapes; the powder coating is uniformly applied through an electrostatic coating method, and it is environmentally friendly as there is no emission of volatile organic compounds (VOCs) during the coating process.

[0016] In addition, a method for manufacturing retroreflective resin powder includes the step of grinding a thermoplastic resin, mixing it with sealed glass beads, and then producing a stabilized powder through extrusion and cooling processes, thereby enabling the production of retroreflective resin powder with high reproducibility and productivity through the above process.

[0017] In addition, the retroreflective resin powder coating method of the present invention can be combined with a primary coating layer of metallic or pearl components in the coating process to maximize brightness and retroreflective performance.

[0018] In addition, the retroreflective resin powder of the present invention has excellent durability and can maintain stable retroreflective performance for a long period even in outdoor environments.

[0019] In addition, the retroreflective resin powder of the present invention has a simpler manufacturing process compared to conventional liquid paints or film methods, and can expand the possibilities for industrial applications by utilizing the advantages of the powder form.

[0020] FIG. 1 is a flowchart illustrating a method for manufacturing a retroreflective resin powder according to an embodiment of the present invention.

[0021] Specific details regarding the problem to be solved, the means for solving the problem, and the effects of the invention as described above are included in the embodiments and drawings to be described below. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described in detail below in conjunction with the accompanying drawings.

[0022]

[0023] In the following, the retroreflective resin powder presented above, the method for manufacturing the same, and the coating method using the same will be described in detail using drawings and examples.

[0024]

[0025] First, the retroreflective resin powder of the present invention is composed of glass beads and a thermoplastic resin.

[0026]

[0027] It is preferable to use enclosed type glass beads for the above glass beads. This is to more stably express retroreflective properties, and compared to the generally used open type glass beads, the enclosed glass beads have a structure in which the outside of the bead is wrapped in a thin translucent layer.

[0028] The above-mentioned blocking type can significantly increase retroreflection efficiency during the light incidence and reflection process.

[0029] More specifically, when an external environment, particularly a water film (moisture) or a transparent coating layer is formed, the open-type glass beads have a problem in which the incidence of light is distorted or the reflection angle changes, causing the retroreflective properties to deteriorate significantly, whereas the sealed-type glass beads have a thin sealing layer that stabilizes the path of light and minimizes the influence of the external environment.

[0030] In addition, while sealed glass beads can exhibit a stable effect because the focal point is fixed inside the glass bead, open glass beads are highly likely to have a focal point that changes with external refractive index (e.g., water or coating agent), so the retroreflection performance of light may become unstable depending on environmental conditions.

[0031] On the other hand, the above-mentioned sealed glass bead has its focal position fixed internally, so the retroreflective performance is maintained consistently even with changes in external conditions.

[0032] In addition, the above-mentioned sealed glass beads have a high refractive index, providing greater retroreflection efficiency. Generally, open-type glass beads have a refractive index of about 1.5 to 1.9, whereas sealed glass beads have a refractive index of 2.2 or higher, which allows for more precise adjustment of the light reflection angle and increased reflection intensity.

[0033] This configuration is essential in painting operations requiring high brightness or in retroreflective applications to improve nighttime visibility.

[0034] That is, in the present invention, by using sealed glass beads as a main component of retroreflective resin powder, stable retroreflective performance can be achieved even when the coated surface is exposed to environmental factors such as water, contaminants, and transparent coating layers.

[0035] In addition, the sealed structure optimizes the incidence and reflection paths of light, providing higher reflection efficiency compared to conventional open-type glass beads.

[0036] In addition, third, the high refractive index of sealed glass beads maximizes brightness and visibility, which can significantly improve the performance of products used at night or in low-light environments.

[0037]

[0038] Meanwhile, it is preferable that the particle size of the glass beads be 30 to 60 μm.

[0039] If the particle size of the glass beads is less than 30 μm, the reflective performance may be reduced, and the glass beads may not be evenly distributed on the coated surface. Conversely, if the particle size exceeds 60 μm, the glass beads may protrude from the coated surface, reducing the uniformity of the coating layer and making it difficult to achieve uniform adhesion of the powder during the coating process.

[0040] Accordingly, in the present invention, the size of the glass beads is optimized to 30 to 60 μm so that retroreflective properties and coating workability can be satisfied simultaneously.

[0041]

[0042] Next, the thermoplastic resin used in the resin powder of the present invention provides structural stability to the retroreflective resin powder and, combined with the sealed glass beads, plays a role in improving the durability and processability of the final coated layer.

[0043] The above thermoplastic resin comprises at least one of polyester, polyurethane, or acrylic resin, and these resins are suitable for various applications depending on their respective characteristics.

[0044] For example, polyester resins provide high chemical resistance and durability, while polyurethane resins offer both flexibility and durability. Acrylic resins have excellent transparency and are advantageous for improving the optical properties of the coating layer in specific environments.

[0045]

[0046] Meanwhile, the retroreflective resin powder of the present invention exhibits optimal performance by setting the sealed glass beads to 10 to 30 weight percent of the total weight in the composition. If the sealed glass beads are less than 10 weight percent, there is a possibility that the retroreflective properties on the coated surface may deteriorate. On the other hand, if the glass beads exceed 30 weight percent, the viscosity of the powder increases, which may make electrostatic coating difficult during the coating process.

[0047] Therefore, by optimizing the glass bead composition ratio as described above, it is possible to simultaneously satisfy painting workability and retroreflective properties.

[0048]

[0049] Meanwhile, the retroreflective resin powder of the present invention is used together with a primary coating layer containing a metallic or pearl pigment in the coating method described below, thereby maximizing retroreflective performance.

[0050] The above first coating layer acts as a base layer that efficiently reflects or disperses light, and can improve the light reflection efficiency by interacting with the retroreflective resin powder applied as a second coating layer.

[0051]

[0052] In addition, the retroreflective resin powder of the present invention mainly consists of the glass beads and resin presented above, and may further include additives such as a curing agent and additives to provide optimal coating workability and coating layer characteristics.

[0053] The curing agent reacts with the thermoplastic resin to more firmly fix the paint layer, thereby enhancing resistance to external impacts or scratches. In particular, the curing agent helps the paint layer stably maintain its retroreflective properties when exposed to external environments such as temperature changes, humidity, and ultraviolet rays.

[0054] As the curing agent used in the present invention, epoxy, polyamine, or melamine-based compounds may be used, and these compounds chemically bond with the thermoplastic resin to induce uniform curing. Such uniform curing ensures that the physical properties of the entire coating layer remain constant and contributes to the formation of a high-quality coating layer.

[0055] In addition, the retroreflective resin powder contains additives to improve the workability of the powder and adjust the properties of the coating layer. The said additives include flow modifiers, gloss modifiers, pigments, dyes, and stabilizers, and these additives can be used alone or in combination.

[0056] The above-mentioned flow modifier helps ensure that retroreflective resin powder is uniformly applied to the surface during the powder coating process. If the powder does not adhere evenly to the surface of the workpiece during electrostatic coating, defects such as bubbles or wrinkles may occur in the coating layer. The flow modifier minimizes such problems and allows the powder to move smoothly during the coating process. Fine particles such as silica or aluminum oxide can be used as flow modifiers, which improve coating performance by reducing surface friction of the powder.

[0057] In addition, gloss modifiers may be included to adjust the gloss level of the coating layer. Since retroreflective effects can vary depending on the gloss level of the coating layer, gloss modifiers are used to achieve optimal optical properties. Wax-based compounds or inorganic additives may be used as gloss modifiers, and these can adjust the surface condition of the coating layer to provide a uniform and beautiful gloss.

[0058] Pigments or dyes may be added to adjust the color of the coating layer or to provide a decorative effect. Pigments are used to adjust the appearance of the coating layer without changing the optical properties of the retroreflective resin powder. For example, in certain applications, metallic pigments or pearl pigments may be used to achieve a color that harmonizes with the retroreflective effect.

[0059] Pigments such as those mentioned above enhance the light scattering effect and provide a visual emphasis effect.

[0060] In addition, stabilizers may be included to improve the heat resistance and moisture resistance of the coating layer. Stabilizers suppress the degradation of components that may occur when the coating layer is exposed to high temperature or humid environments, and help maintain the physical properties of the coating layer for a long period. Such stabilizers play an important role, especially when using retroreflective resin powder in structures or equipment exposed to the external environment.

[0061]

[0062] In the present invention, the sealed glass beads and thermoplastic resin account for 80 to 95% of the total composition, and the curing agent and additives are preferably used as auxiliary components to optimize the physical stability, workability, and optical properties of the coating layer.

[0063]

[0064] Meanwhile, in order to secure retroreflective performance, the retroreflective resin powder of the present invention may selectively use only glass beads whose reflection efficiency calculated by the following mathematical formula 1 exceeds a preset value (0.015 to 0.10).

[0065]

[0066] [Mathematical Formula 1]

[0067]

[0068] Here,

[0069] R: Glass bead reflection efficiency,

[0070] η: Arrangement density of glass beads (set to a value between 0 and 1),

[0071] n2: Refractive index of glass beads

[0072] n1: Refractive index of the resin

[0073] d opt : Optimal particle size (㎛)

[0074] d act : Actual particle size (㎛)

[0075] k: Defined as the damping coefficient (0 < k ≤ 1) due to particle size imbalance.

[0076]

[0077] The above mathematical formula 1 can additionally consider the influence of the particle size and arrangement density of the glass beads on the reflection efficiency, as well as the difference in refractive index between the glass beads and the resin.

[0078] The term represents the reflection intensity according to the difference in refractive index, and The term reflects how close the actual particle size of the glass beads is to the optimal particle size.

[0079]

[0080]

[0081] In the present invention, the refractive index n2 is set to 2.2 or higher and n1 to 1.5, and the optimal particle size d opt can be set to 45㎛. Array density η was set to 0.8, and k was set to 0.8 to indicate the reduction in efficiency due to particle size imbalance.

[0082]

[0083] For example, d act When = 50㎛, array density η= 0.8, refractive index n2= 2.3, n1= 1.5, the reflection efficiency R is calculated as follows.

[0084]

[0085]

[0086]

[0087]

[0088] In the above calculation, since the reflection efficiency R exceeds a preset reference value (R > 0.015), the glass bead is determined to be suitable for the retroreflective resin powder of the present invention.

[0089]

[0090] In addition, by adding a factor based on coating thickness, only glass beads whose reflection efficiency calculated by the following mathematical formula 2 exceeds a preset value (0.015 to 0.10) can be selectively selected and used.

[0091] [Mathematical Formula 2]

[0092]

[0093]

[0094] Here,

[0095] R: Glass bead reflection efficiency,

[0096] η: Arrangement density of glass beads (set to a value between 0 and 1),

[0097] n2: Refractive index of glass beads

[0098] n1: Refractive index of the resin

[0099] d opt : Optimal particle size (㎛)

[0100] d act : Actual particle size (㎛)

[0101] k: Damping coefficient due to particle size imbalance (0 < k ≤ 1)

[0102] t : Coating thickness (㎛)

[0103] t crit : Critical coating thickness (㎛) (t crit In the above, it is defined as (reflection performance is saturated).

[0104]

[0105] The above Equation 2 comprehensively considers the influence of refractive index difference, array density, particle size, and coating layer thickness on retroreflective efficiency.

[0106]

[0107] represents the nonlinear effect of coating thickness on reflection efficiency. The coating thickness t is a specific threshold t crit It reflects the characteristic that the reflection efficiency saturates when it reaches.

[0108]

[0109] In the present invention, the refractive index n2 is set to 2.2 or higher and n1 to 1.5, and the optimal particle size d opt can be set to 45㎛. The array density η was set to 0.8, and k was set to 0.8 to indicate the efficiency reduction due to particle size imbalance. In addition, the critical coating thickness t crit It was set to 10㎛.

[0110]

[0111] For example, d act When = 50㎛, array density η= 0.8, refractive index n2= 2.3, n1= 1.5, and coating thickness t=8㎛, the reflection efficiency R is calculated as follows.

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] In the above calculation, since the reflection efficiency R exceeds a preset reference value (R > 0.015), the glass bead is determined to be suitable for the retroreflective resin powder of the present invention.

[0118]

[0119] In the present invention, based on the above mathematical formulas 1 and 2, the reflection efficiency is numerically evaluated and the refractive index, particle size, and arrangement density of the glass beads are optimized to maximize retroreflective performance.

[0120]

[0121] The method for manufacturing the above retroreflective resin powder is described below.

[0122]

[0123] The retroreflective resin powder of the present invention can be manufactured according to Examples 1 to 3 presented below.

[0124]

[0125] [Example 1]

[0126] In Example 1 above, a retroreflective resin powder is prepared by adding glass beads in the manufacturing process of a thermoplastic resin.

[0127] More specifically, in the resin synthesis process starting from the raw material mixing stage, glass beads are introduced to manufacture the resin. The introduced glass beads are uniformly mixed with the resin through a mixer. During the mixing process, the glass beads are evenly distributed within the resin to form a structure capable of maximizing retroreflective properties.

[0128] The above-mentioned mixed mixture is transferred to an extruder and solidified, and after the mixture is extruded at a high temperature (the internal temperature of the extruder is maintained at 60 to 130°C), it passes through a cooler and is stabilized in a solid state. The stabilized solid is transferred to a grinder and finally ground to a particle size of 30 to 100 μm to complete the manufacture of retroreflective resin powder.

[0129]

[0130] [Example 2]

[0131] In Example 2 above, a retroreflective resin powder is prepared by mixing crushed resin and blocking glass beads.

[0132] More specifically, it is explained with reference to FIG. 1, which is a flowchart showing a method for manufacturing a retroreflective resin powder according to Example 2 of the present invention.

[0133]

[0134] First, in the first step (S10), the thermoplastic resin is crushed.

[0135] The above thermoplastic resin is composed of at least one of polyester, polyurethane, and acrylic resin, and the solid resin is fed into a grinder to adjust the particle size to 30 to 100 μm.

[0136] In the first step above, a multi-stage sieving process may be performed in parallel to ensure a uniform size of the powder, and the powder formed in the above process is used as a matrix for preparing to mix with sealed glass beads.

[0137] The above-mentioned crushed resin is transferred to a mixer in a stable state.

[0138]

[0139] Next, in the second step (S20), sealed glass beads are added to the crushed resin and mixed.

[0140] It is preferable that the above-mentioned blocking glass beads have a refractive index of 2.2 or higher and a particle size of 30 to 60 μm.

[0141] The mixer for the above mixing is operated at a temperature of 60 to 130°C and is set so that the crushed resin and the sealed glass beads are uniformly mixed.

[0142] During the above mixing process, as the resin softens, the glass beads penetrate into the resin or are stably fixed within the matrix.

[0143] The above mixing time is set to 30 to 60 minutes, and the mixing speed and temperature can be adjusted so that the glass beads and resin are uniformly bonded.

[0144]

[0145] Next, in the third step (S30), the mixed mixture is extruded to solidify.

[0146] The above-mentioned mixed mixture is transferred to an extruder, and the internal temperature of the extruder is maintained at 60 to 130°C. During the extrusion process, the mixture is subjected to constant pressure and extruded into a long, uniform solid form.

[0147] The above extrusion process is designed so that the sealed glass beads and the resin are bonded more strongly, thereby forming a solid composition with excellent retroreflective properties.

[0148] The above extruded material can be cut into a specific length and thickness before moving to the cooling process.

[0149]

[0150] Next, in step 4 (S40), the solidified composition is cooled.

[0151] The above-mentioned cooler for cooling passes the solidified composition through it and converts it into a stable solid state.

[0152] The above cooling process helps physically stabilize the solidified composition and completes preparation for the subsequent grinding process.

[0153]

[0154] Next, in step 5 (S50), the coolant is crushed to finally produce retroreflective resin powder.

[0155] The above-mentioned cooled material is fed into a grinder and the particle size is adjusted to 30 to 100 μm.

[0156] Through the above grinding process, a powder in which glass beads and resin are uniformly distributed is formed, and the powder formed as described above is ready to be used in the coating process.

[0157]

[0158]

[0159] [Example 3]

[0160] The above Example 3 imparts retroreflective properties by mixing a transparent powder made of thermoplastic resin with a blocking glass bead.

[0161]

[0162] More specifically, a transparent powder is manufactured based on a thermoplastic resin. The particle size of the transparent powder is adjusted to 30 to 100 μm or less.

[0163] The above transparent powder forms the basic composition of the retroreflective resin powder and provides a matrix in which blocking glass beads can be uniformly distributed.

[0164] The above transparent powder and sealed glass beads are fed into a mixer, and the mixing ratio is adjusted so that the sealed glass beads account for 10 to 30 weight percent of the total composition.

[0165] The above mixer is heated to 60 to 130°C to provide an environment in which the transparent powder softens and can be uniformly mixed with glass beads. The mixing process is carried out for 30 to 60 minutes, and during the mixing process, the glass beads are evenly distributed within the matrix.

[0166] The above-mentioned mixed mixture is solidified through an extruder, and the solidified composition is stabilized by passing through a cooler. The stabilized solid is finally adjusted to a particle size of 30 to 100 μm through a grinder.

[0167] The retroreflective resin powder manufactured as described above has both transparency and retroreflective properties, and when used together with a primary coating layer of metallic and pearl components in the coating method described below, the retroreflective performance is maximized.

[0168]

[0169] The above retroreflective resin powder coating method is described below.

[0170] First, in step a, the surface of the workpiece is prepared. Contaminants such as dust, oil, and rust present on the surface are removed to ensure good adhesion of the paint.

[0171] The above surface preparation process is an important step in determining the quality of the paint, and if the surface preparation is not performed properly, the paint layer may peel off easily or the retroreflective performance may be degraded.

[0172] The above surface preparation can be carried out through mechanical or chemical methods. For example, the surface is cleaned using methods such as sandblasting or solvent cleaning, and activated so that the paint can adhere well.

[0173]

[0174] Next, in step b (S20), a primary coating layer is formed. Specifically, a primary coating layer containing a metallic or pearl pigment is applied to the surface of the workpiece and cured.

[0175] The above primary coating layer acts as a base layer to maximize retroreflective performance by interacting with the retroreflective resin powder. Metallic or pearl pigments serve to efficiently reflect or disperse light, and the reflection characteristics of the retroreflective resin powder applied as a secondary coating layer can be improved due to the above primary coating layer.

[0176] The above-described primary coating layer is cured at a temperature of 160 to 200°C for 10 to 30 minutes, and when the curing process is performed under these conditions, a solid and uniform coating layer is formed.

[0177]

[0178] Next, in step c, a second coating layer is formed. Specifically, a second coating layer is applied over the first coating layer using retroreflective resin powder.

[0179] The above secondary coating layer serves to exhibit retroreflective properties, and retroreflective resin powder is uniformly applied through an electrostatic coating method.

[0180] The above electrostatic coating method charges paint particles with electricity to ensure they adhere evenly to the surface of the workpiece, enabling uniform application even on workpieces with complex shapes or curved surfaces.

[0181] In the above process of applying the second coating layer, the retroreflective resin powder combines with the first coating layer to form a structure that can maximize light reflection efficiency.

[0182]

[0183]

[0184] Next, in step d, the secondary coating layer is cured. Specifically, the secondary coating layer is cured by heating at a temperature of 160 to 200°C for 10 to 30 minutes.

[0185] During the above curing process, the thermoplastic resin of the retroreflective resin powder and the blocking glass beads are stably bonded, and due to the bonding, the retroreflective properties of the coating layer are expressed.

[0186] The above-mentioned hardened secondary coating layer has high brightness and durability, and can stably maintain retroreflective performance even in an external environment.

[0187]

[0188] The retroreflective resin powder coating formed through the above process provides high brightness and uniform coating properties, and can maximize the retroreflective effect in various industrial applications.

[0189]

[0190] As such, those skilled in the art to which the present invention pertains will understand that the technical configuration of the present invention described above can be implemented in other specific forms without altering the technical concept or essential features of the present invention.

[0191] Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting, and the scope of the invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the invention.

[0192] S10. First step of grinding the resin

[0193] S20. A second step of adding sealed glass beads to the crushed resin and mixing.

[0194] S30. A third step of solidifying the above-mentioned mixed mixture by extruding it.

[0195] S40. Fourth step of cooling the solidified mixture above

[0196] S50. 5th step of crushing the above-mentioned cooling material

Claims

1. As a retroreflective resin powder, Blocked glass beads and; It includes a thermoplastic resin, The above-mentioned occluded glass beads have a particle size of 30 to 60 μm and a refractive index of 2.2 or higher, and The above thermoplastic resin is a retroreflective resin powder characterized by comprising at least one of polyester, polyurethane, and acrylic resin.

2. In Paragraph 1, The above retroreflective resin powder is, Retroreflective resin powder characterized by being additionally applied over a coating layer containing a metallic or pearl pigment applied as a primary coating layer.

3. First step of crushing the resin; A second step of adding sealed glass beads to the above-mentioned crushed resin and mixing; A third step of solidifying the above-mentioned mixed mixture by extruding it; A fourth step of cooling the solidified mixture; A method for manufacturing retroreflective resin powder characterized by including a fifth step of crushing the above-mentioned cooling material.

4. In Paragraph 3, A method for manufacturing retroreflective resin powder characterized in that the above resin is a thermoplastic resin. 5.a) Step of preparing the surface of the workpiece; b) A step of applying and curing a primary coating layer containing metallic or pearl pigments to the surface of the workpiece; c) A step of applying a second coating layer on the first coating layer using retroreflective resin powder; d) A retroreflective resin powder coating method characterized by including a step of curing the secondary coating layer.

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