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KR-102961651-B1 - Paint composition for outdoor safety signs, film for outdoor safety signs including a paint layer formed therefrom, and outdoor safety signs including the same

KR102961651B1KR 102961651 B1KR102961651 B1KR 102961651B1KR-102961651-B1

Abstract

A film for outdoor safety signs according to one embodiment of the present invention comprises two epoxy layers and a paint layer formed from a paint composition for outdoor safety signs described between them. As a result, the temperature sensitivity of the thermochromic pigment can be maintained even after accelerated testing under harsh conditions, thereby having the effect of significantly improving lightfastness and weather resistance. Accordingly, it can be easily applied to outdoor uses where it was difficult to apply conventionally, and specifically, it can be applied to road freezing warning signs.

Inventors

  • 임보규
  • 김예진
  • 정서현
  • 박상준
  • 김정탁

Assignees

  • 한국화학연구원

Dates

Publication Date
20260508
Application Date
20221207

Claims (17)

  1. A substrate; a first epoxy layer; a paint layer formed from a paint composition for outdoor safety signs; and a second epoxy layer, wherein the paint layer is interposed between the first epoxy layer and the second epoxy layer. The paint composition for outdoor safety signs described above comprises an epoxy resin, a curing agent, a thermochromic pigment, an organic solvent, a reactive diluent, a UV absorber, an amine-based light stabilizer (HALS), and an antioxidant, and The above epoxy resin has two or more epoxy groups within its molecule, and The above-mentioned reactive diluent is a C 12-20 aliphatic glycidyl ether, for an outdoor safety sign film.
  2. In paragraph 1, The above thermochromic pigment is a film for outdoor safety signs that changes color at a temperature of -5 to 25℃.
  3. delete
  4. In paragraph 1, The cured product of the above epoxy resin is a film for outdoor safety signs having an oxygen permeability of 30 cc/㎡·day·atm or less and a moisture permeability of 50 g/㎡·day or less at a thickness of 100 µm.
  5. In paragraph 1, The above-mentioned UV absorber is a triazine-based UV absorber, used in outdoor safety signage films.
  6. In paragraph 1, The above-mentioned ultraviolet absorber is a triazine-based ultraviolet absorber containing at least one hindered phenol group in its molecule, and is a film for outdoor safety signs.
  7. In paragraph 1, The above-mentioned reactive diluent is included in an amount of 5 to 50 parts by weight per 100 parts by weight of epoxy resin in a film for outdoor safety signs.
  8. In paragraph 1, The above thermochromic pigment is included in an amount of 1 to 25 parts by weight per 100 parts by weight of epoxy resin in a film for outdoor safety signs.
  9. In paragraph 1, A film for outdoor safety signs containing the above organic solvent in an amount of 15 to 200 parts by weight per 100 parts by weight of epoxy resin.
  10. In paragraph 1, A film for outdoor safety signs containing the above curing agent in an amount of 5 to 50 parts by weight per 100 parts by weight of epoxy resin.
  11. In paragraph 1, The above-mentioned ultraviolet absorber is included in an amount of 0.1 to 30 parts by weight per 100 parts by weight of epoxy resin in a film for outdoor safety signs.
  12. In paragraph 1, The above paint layer is a film for outdoor safety signs in which a thermochromic pigment is dispersed on an epoxy resin matrix.
  13. In paragraph 1, A film for outdoor safety signs further comprising an acrylic UV blocking layer on the second epoxy layer.
  14. In paragraph 1, An outdoor safety sign film comprising an oxygen blocking layer on at least one surface of the above outdoor safety sign film.
  15. In paragraph 1, The above outdoor safety sign film is an outdoor safety sign film that satisfies the following Equation 1 when the temperature changes from room temperature to 4℃ after a weather resistance test under 500-hour conditions. [Equation 1] ΔE 500 /ΔEi > 0.35 In Equation 1 above, ΔE 500 is the total color difference when the temperature changes from room temperature to 4°C after a weathering test under 500 hours conditions, and ΔEi is the total color difference (ΔE) when the temperature changes from room temperature to 4°C before the weathering test.
  16. An outdoor safety sign comprising a film for an outdoor safety sign according to any one of paragraphs 1, 2, and 4 through 15.
  17. In Paragraph 16, The above outdoor safety sign is an outdoor safety sign that serves as a road icing warning sign.

Description

Paint composition for outdoor safety signs, film for outdoor safety signs including a paint layer formed therefrom, and outdoor safety signs including the same The present invention provides a paint composition for outdoor safety signs, a film for outdoor safety signs comprising a paint layer formed therefrom, and an outdoor safety sign comprising the same. Thermochromic pigments refer to pigments that change color at a specific temperature. Thermochromic pigments are classified into reversible or irreversible types; they undergo a process where they are colorless at a reference temperature and return to their original color when the temperature returns. Reversible thermochromic pigments can be used multiple times as they return to their original color even after repeating this process, whereas irreversible thermochromic pigments are single-use. Generally, reversible thermochromic pigments have a reference temperature range of -15°C to 70°C, while irreversible thermochromic pigments have a reference temperature range of 40°C to 450°C. Specifically, thermochromic pigments exist in the form of ultrafine microcapsules and contain two materials: an electron donor and an electron acceptor. Depending on the reference temperature, the electron donor and electron acceptor interact to reveal the colored color of the crystal, while applying heat causes the electron acceptor to detach, thereby allowing the crystal to display a colorless state. Through this series of processes, thermochromic pigments are capable of reversibly and repeatedly changing color from colorless to colored, or from colored to colored, depending on the selection of the electron acceptor. Paint compositions are also manufactured using thermochromic pigments that possess these characteristics, and are used to provide warnings through color changes when exposed to sudden temperature changes. However, although they were intended for application to road freezing warning signs, existing paint compositions using thermochromic pigments have the disadvantage of very poor lightfastness, as the color change characteristics of the thermochromic pigment disappear within a few days when exposed to sunlight. To address these issues, much research has been conducted to improve the lightfastness of paints containing thermochromic pigments by introducing UV blockers/absorbers; however, sufficient improvement in lightfastness has not yet been achieved, and in particular, it is currently impossible to use them for exterior applications. Therefore, there is an urgent need for research and development on paint compositions containing thermochromic pigments that exhibit excellent lightfastness and weather resistance. Figure 1 shows sample images of films for outdoor safety signs according to Comparative Example 1, Examples 1 and 4 at room temperature and low temperature (4°C) before and after 50 and 100 hours of acceleration, and at room temperature and low temperature (4°C). It was confirmed that Comparative Examples 1 and 3 showed insufficient temperature sensitivity to low temperature after testing, whereas Example 1 maintained excellent temperature sensitivity even after testing. Figure 2 shows images of outdoor safety sign films according to Comparative Examples 1 and 3 and Examples 1, 3, and 4 at 4°C before and after a 500-hour accelerated test based on ASTM G155. Although all exhibited excellent temperature sensitivity before the test, Comparative Examples 1 and 3 showed poor temperature sensitivity after the test, while Examples 1, 3, and 4 maintained excellent temperature sensitivity. Unless otherwise defined, technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the invention are omitted in the following description and accompanying drawings. Additionally, the singular form used in this specification may be intended to include the plural form unless specifically indicated otherwise in the context. Additionally, units used herein without special reference are based on weight, and, for example, units of % or ratio mean weight % or weight ratio, and weight % means the weight percentage of any one component of the total composition that occupies the composition, unless otherwise defined. Additionally, the numerical ranges used in this specification include lower and upper limits and all values within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in this specification, values outside the numerical range that may occur due to experimental error or rounding are also included in the defined numerical range. The term "comprising" in this specification i