Thermochromic retroreflective composite material and use thereof

Abstract

A thermochromic retroreflective composite material has an adhesive layer and a thermochromic retroreflective layer on a surface of the adhesive layer. A reflector is partially embedded in the thermoch

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of reflective materials, and in particular, to a thermochromic retroreflective composite material and use thereof. BACKGROUND

[0002] Amid global climate anomaly and rapid urbanization, the urban thermal environment problems represented by heat island effect become more and more obvious. The regional thermal environment problems of high-rise high-density buildings are particularly prominent, with serious problems such as local overheating and poor ventilation. In the deteriorating regional thermal environment, the dependence on artificial energy increases, and the air-conditioning energy consumption increases significantly in summer. The high air-conditioning energy consumption increases the thermal load of the buildings and worsens the regional thermal environment again. Thus, a vicious cycle of "regional thermal environment deteriorates -air-conditioning energy consumption intensifies" is formed. Therefore, it is very important to study the urban heat island problem and energy consumption caused by the regional thermal environment deterioration of high-rise high-density buildings.

[0003] Improving the solar radiation reflectivity of the building surface is an effective way to reduce the solar radiation heat of the building. However, traditional highly reflective materials are reflected by diffuse reflection or diffuse specular reflection, and the reflected solar radiation is received by nearby buildings or streets. Therefore, highly reflective materials have a significant energy-saving effect on a single building, while have a low potential to improve the thermal environment of the whole building region, or even further deteriorate the regional thermal environment.

[0004] The retroreflective material can reflect the solar radiation in the direction of the incident radiation, which is applied in the field of building thermal environment. The reflecting surface of the prism or glass bead can be applied with near infrared highly reflective materials, which can reduce the radiant heat of the building, and does not transfer the radiant heat to adjacent buildings. Thus, the problem of "regional thermal environment deteriorates^air-conditioning energy consumption intensifies" is alleviated. However, when used in winter, the retroreflective material makes internal and external surfaces of the building cooler, which increases the winter heating load in turn. 09 10 23 SUMMARY

[0005] In view of this, an objective of the present disclosure is to provide a thermochromic retroreflective composite material and use thereof. The composite material provided by the present disclosure can improve a building thermal environment, alleviate an urban heat island effect, and save heating energy consumption.

[0006] To achieve the above objective of the present disclosure, the present disclosure provides the following technical solutions.

[0007] The present disclosure provides a thermochromic retroreflective composite material, including an adhesive layer and a thermochromic retroreflective layer on a surface of the adhesive layer. The thermochromic retroreflective layer includes a thermochromic layer in contact with the adhesive layer and a reflector partially embedded in the thermochromic layer. The reflector includes a prism cone or a glass bead. An upper surface of the prism cone is parallel to the adhesive layer.

[0008] Preferably, the thermochromic layer is formed by a thermochromic coating, and the thermochromic coating is a thermochromic ink 1011.

[0009] Preferably, the thermochromic layer has a thickness of 0.1-0.8 mm.

[0010] Preferably, when the reflector is the prism cone, the partial embedding refers to embedding of other parts of the reflector except an upper surface in the thermochromic layer.

[0011] When the reflector is the glass bead, the partial embedding refers to embedding of 40-60% of a height of the reflector in the thermochromic layer.

[0012] Preferably, the reflector includes a reflector with a transparent resin coating layer.

[0013] Preferably, the transparent resin coating layer has a thickness of 0.1-0.3 mm.

[0014] Preferably, the prism cone has a stereoscopic acceptance angle of 45-55° and a height of 0.4-0.6 mm.

[0015] Preferably, the glass bead has a particle size of 0.1-0.6 mm.

[0016] Preferably, the thermochromic retroreflective composite material further includes a transparent resin layer on a surface of thermochromic retroreflective layer.

[0017] The present disclosure provides use of the thermochromic retroreflective composite material according to the above technical solution in a construction industry.

[0018] When the thermochromic retroreflective composite material provided by the present disclosure is applied to an exterior wall of a building, incoming sunlight is reflected through two refractions at a boundary of a prism cone and two reflections on a thermochromic layer. Or, the incoming sunlight is reflected in an incident direction through two refractions at a boundary of a glass bead and one reflection on the thermochromic layer, so as to achieve retroflection of more solar radiation in summer. Thus, a building thermal environment can be improved, and an urban 09 10 23 heat island effect can be alleviated. In addition, more solar radiation can be absorbed in winter to save heating energy consumption. In particular, needs of building thermal environment in different seasons in hot summer and cold winter regions can be met, greatly reducing building energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS [00191 FIG. 1 is a sectional view of a thermochromic prism-type retroreflective composite material;

[0020] FIG. 2 is a sectional view of a thermochromic glass bead-type retroreflective composite material; and

[0021] FIG. 3 is a sectional view of a thermochromic capsule bead-type retroreflective composite material. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present disclosure provides a thermochromic retroreflective composite material, including an adhesive layer and a thermochromic retroreflective layer on a surface of the adhesive layer. The thermochromic retroreflective layer includes a thermochromic layer in contact with the adhesive layer and a reflector partially embedded in the thermochromic layer. The reflector includes a prism cone or a glass bead. An upper surface of the prism cone is parallel to the adhesive layer.

[0023] In the present disclosure, unless otherwise specified, all raw material components are commercially available products well known to persons skilled in the art.

[0024] In the present disclosure, an adhesive preferably includes the following preparation raw materials in mass percentage: 30-40% of polyol, 15-20% of an isocyanate crosslinking agent, and 40-55% of ethyl acetate, more preferably, 35-38% of polyol, 16-18% of an isocyanate crosslinking agent, and 44-49% of ethyl acetate, and further preferably, 37.2% of polyol, 17.3% of an isocyanate crosslinking agent, and 45.5% of ethyl acetate. The polyol is preferably polyester polyol, more preferably, VITAL 3650 (RTM) (Bostik, Inc., RTM). The isocyanate crosslinking agent is preferably DESMODUR L75 (RTM) (Bayer, RTM). In the present disclosure, the adhesive layer has a thickness of preferably 0.1-0.2 mm. In the present disclosure, the adhesive layer can maintain the shape of the composite material and bond the thermochromic layer.

[0025] In the present disclosure, the thermochromic layer has a thickness of preferably 0.1-0.8 mm, more preferably 0.1-0.7 mm, and specifically preferably 0.1-0.5 mm. The thermochromic layer is formed by a thermochromic coating. The thermochromic coating is preferably a thermochromic ink 1011, and its chemical composition is shown in Table 1. The color of the thermochromic coating used in the present disclosure changes with the temperature, and has different solar radiation absorption characteristics. The thermochromic layer presents a black tone with radiation reflectivity of 20% when the temperature is greater than 35°C and a white tone with radiation reflectivity of 80% when the temperature is less than or equal to 25°C. The radiation reflectivity of the thermochromic layer changes linearly between 25°C and 35°G W hen applied in the outer building envelope, it has a low absorption rate in summer and a high absorption rate in winter, which can inhibit the heat increase of the building in summer, and promote the heat increase in winter, such that the composite material can meet the needs of the building thermal environment in different seasons. 09 10 23

[0026] Table 1 Chemical composition of thermochromic ink 1011 Component Content / wt.% CSANo. PVC resin 40 201058-08-4 Invisible dye 10 21931-68-9 Melamine-epoxy polymer 20 9003-08-1 Color fonning agent 10 50292-95-0 Temperature control agent 10 36431-22-8 Diluent 5 112-02-5 Additive 5 1166-52-5

[0027] In the present disclosure, the prism cone has a stereoscopic acceptance angle of preferably 45-55°, and more preferably 50°, and a height of preferably 0.4-0.6 mm, and more preferably 0.5 mm. The prism cone is preferably a triangular or quadrilateral pyramid. In the present disclosure, the glass bead has a particle size of preferably 0.1-0.6 mm, and more preferably 0.1-0.3 mm or 0.4-0.6 mm, and refractivity of preferably 1.9. In the present disclosure, the reflector preferably includes a single reflector or a reflector with a transparent resin coating layer. The transparent resin coating layer has a thickness of preferably 0.1-0.3 mm, and more preferably 0.1-0.2 mm.

[0028] In the present disclosure, when the reflector is the prism cone, the partial embedding preferably refers to embedding of other parts of the reflector except an upper surface (that is, the upper surface parallel to the adhesive layer) in the thermochromic layer. When the reflector is the glass bead, the partial embedding preferably refers to embedding of 40-60% (more preferably 50%) of a height of the reflector in the thermochromic layer.

[0029] In the present disclosure, the thermochromic retroreflective composite material 09 10 23 preferably further includes a transparent resin layer on a surface of thermochromic retroreflective layer. The transparent resin layer has a thickness of preferably 0.1-0.3 mm. When the reflector is the glass bead, a gap between the transparent resin layer and the glass bead is air or transparent resin.

[0030] In the present disclosure, the transparent resin coating layer, the transparent resin layer, and the transparent resin in the gap independently preferably include polyurethane resin.

[0031] The present disclosure provides use of the thermochromic retroreflective composite material according to the above technical solution in a construction industry. The application is preferably application in the outer building envelope. When applied, the adhesive layer of the thermochromic retroreflective composite material is in contact with the outer wall of the building.

[0032] The technical solutions of the present disclosure will be described below clearly and completely in conjunction with the examples of the present disclosure. Apparently, the described examples are only a part of, not all of, the examples of the present disclosure. All other examples obtained by those of ordinary skill in the art based on the examples of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0033] In the following examples of the present disclosure, the adhesive layer is prepared with the following raw materials: 37.2 wt.% of VITAL 3650 (RTM), 17.3 wt.% of DESMODUR L75 (RTM), and 45.6 wt.% of ethyl acetate. The thermochromic layer is obtained by coating with the thermochromic ink 1011 shown in Table 1 and drying.

[0034] Example 1

[0035] A sectional view of a thermochromic prism-type retroreflective composite material is shown in FIG. 1. The composite material included an adhesive layer (with a thickness of 0.1 mm), a thermochromic layer on a surface of the adhesive layer (with a thickness of 0.5 mm), and a triangular prism (with a stereoscopic acceptance angle of 50° and a height of 0.5 mm) whose other parts were embedded in the thermochromic layer except the upper surface parallel to the adhesive layer.

[0036] Example!

[0037] A sectional view of a thermochromic glass bead-type retroreflective composite material is shown in FIG. 2. The composite material included an adhesive layer (with a thickness of 0.1 mm), a thermochromic layer on a surface of the adhesive layer (with a thickness of 0.2 mm), a glass bead (with refractivity of 1.9 and a particle size of 0.2 mm) 50% of which were embedded in the thermochromic layer, and a transparent resin layer on a surface of the glass bead (with a thickness of 0.1 mm, and the resin type was polyurethane resin). A gap between the transparent resin layer and the glass bead was air. 09 10 23

[0038] Example 3

[0039] A sectional view of a thermochromic capsule bead-type retroreflective composite material is shown in FIG. 3. The composite material included an adhesive layer (with a thickness of 0.1 mm), a thermochromic layer on a surface of the adhesive layer (with a thickness of 0.2 mm), a glass bead (with refractivity of 1.9 and a particle size of 0.3 mm) 50% of which were embedded in the thermochromic layer, a transparent resin coating layer (with a thickness of 0.5 mm) on a surface of the glass bead, and a transparent resin layer on the surface of the glass bead (with a thickness of 0.1 mm, and the resin type was polyurethane resin). A gap between the transparent resin layer and the glass bead was transparent resin.

[0040] When the composite material provided by the present disclosure was applied to the outer building envelope, incoming sunlight was reflected through two refractions at a boundary of the prism and two reflections on a thermochromic layer (Example 1). Or, the incoming sunlight was reflected in an incident direction through two refractions at a boundary of a glass bead, two refractions of the glass bead and the transparent resin interface, and one reflection on the thermochromic layer (Examples 2 to 3), so as to achieve retroflection of more solar radiation in summer. Thus, a building thermal environment could be improved, and an urban heat island effect could be alleviated. In addition, more solar radiation could be absorbed in winter to save heating energy consumption.

[0041] Comparative Example 1

[0042] This example showed a coating with radiation reflectivity of 90% (AllgllAG-nano thermal insulation coating).

[0043] Comparative Example 2

[0044] This example showed ordinary red roofing tiles with radiation reflectivity of 48% (See: Xiao xingliang. Reflection properties testing of roofing materials [J], Value Engineering, 2013,32(25):87-88.DOI:10.14018 / j.cnki.cnl3-1085 / n.2013.25.072.)

[0045] Comparative Example 3

[0046] This example showed "Cold" black linoleum tiles with radiation reflectivity of 12% (See: Excerpt from Xiao Shi. Research on non white "cold" roofing products [J], China Building Waterproofing, 2005(09):38-40.)

[0047] Test Example 1

[0048] The composite material of Examples 1 to 3 and the coating of Comparative Examples 1 to 3 in the present disclosure were applied to the building surface in Nanjing, a typical hot summer and cold winter region, to carry out the transient temperature test of the outer surface of the building on the typical day of each month for 12 months (on the 15th day of each month, the test was postponed when the situation was obviously not in line with the climate condition of the month). Temperature data was recorded every two minutes. The maximum surface temperature (the maximum temperature tested every day) and the average surface temperature (the average temperature tested on a typical day) calculated by natural month were the average temperatures of the month. The test results are shown in Table 2: 09 10 23

[0049] Table 2 Average temperature of building surface Mon th Maximum temperature / °C Average temperature / °C Examp Ie 1 Examp Ie 2 Examp Ie 3 Comparat ive Example 1 Comparat ive Example 2 Comparat ive Example 3 Examp Ie 1 Examp Ie 2 Examp Ie 3 Comparat ive Example 1 Comparat ive Example 2 Comparat ive Example 3 1 21.97 23.12 23.32 12.11 21.40 31.66 5.93 6.82 7.08 3.31 5.80 8.29 2 22.37 23.76 23.98 10.25 23.32 36.86 4.32 5.17 5.84 1.51 4.81 8.12 3 41.78 42.13 42.36 20.69 36.31 51.93 15.31 16.12 16.71 11.26 15.72 20.18 4 42.15 43.06 43.26 26.52 43.19 60.65 21.04 22.07 22.89 17.65 23.05 28.45 5 35.84 36.05 36.47 32.37 50.63 69.17 21.87 22.94 23.45 21.77 27.86 33.95 6 37.86 38.14 38.79 36.72 54.04 71.91 26.42 27.91 28.16 26.96 33.02 39.09 7 47.21 48.07 48.96 45.75 63.47 81.66 35.98 36.84 37.46 36.58 42.50 48.42 8 39.04 40.17 41.36 38.49 56.64 75.09 29.87 30.73 31.12 30.87 36.40 41.93 9 35.17 36.64 36.94 34.11 52.05 70.22 25.46 26.08 26.45 25.22 30.76 36.30 10 29.76 41.04 41.78 25.16 41.25 57.34 18.42 19.94 20.46 16.47 20.61 24.75 11 29.01 30.15 30.81 18.62 31.54 44.94 13.48 14.06 14.48 11.41 14.99 18.56 12 21.87 22.35 22.68 6.21 17.99 29.80 6.32 7.46 7.79 3.54 6.30 9.06

[0050] It can be seen from Table 1 that in July when the average temperature is the highest, the maximum surface temperature of the composite material provided by Example 1 of the present disclosure is 1.46°C higher than that of the material provided by Comparative Example 1, and the average surface temperature is 0.6°C lower. The maximum surface temperature and avera^ surface temperature are 16.26°C and 6.52°C lower than those of the material provided by Comparative Example 2 respectively. The maximum surface temperature and average surface temperature are 34.45°C and 12.44°Clower than those of the material provided by Cbmparative Example 3 respectively.

[0051] In January when the average temperature is the lowest, the maximum surface temperature and average surface temperature of the composite material provided by Example 1 09 10 23 of the present disclosure are 9.86°C and 2.62°C higher han those of the material provided by Comparative Example 1 respectively. The maximum surface temperature is 0.57°C lower than that of the material provided by Comparative Example 2, and the average surface temperature is 0.13°C higher. The maximum surface-temperature and average surface temperature are only 9.69°C and 2.36°C lower than those of the material provided by Comparative Example 3 respectively. Compared with Comparative Examples 1 to 3, the composite material provided in Example 1 of the present disclosure reduced the annual heating load and cooling load of Nanjing by 4.45%, 18.67%, and 47.46% respectively.

[0052] From a year-round perspective, the composite material provided by the present disclosure is applied to the building surface, which can absorb more solar radiation in winter while achieving retrotlection of solar radiation in summer. In particular, needs of building thermal environment in different seasons in hot summer and cold winter regions can be met, greatly reducing building energy consumption. The material has excellent comprehensive performance.

[0053] The above descriptions are merely preferred implementations of the present disclosure. It should be noted that those of ordinary skill in the art may further make several improvements and modifications without departing from the principle of the present disclosure, but such improvements and modifications should be deemed as falling within the protection scope of the present disclosure.

Claims

10 09 241. A thermochromic retroreflective composite material, comprising an adhesive layer and a thermochromic retroreflective layer on a surface of the adhesive layer, wherein the thermochromic retroreflective layer comprises a thermochromic layer in contact with the adhesive layer and a reflector partially embedded in the thermochromic layer; the reflector comprises a prism cone or a glass bead; an upper surface of the prism cone is parallel to the adhesive layer;the thermochromic layer has a thickness of 0.1-0.8 mm; andthe thermochromic layer presents a black tone with radiation reflectivity of 20% when the temperature is greater than 35 °C and a white tone with radiation reflectivity of 80% when the temperature is less than or equal to 25 °C; and the radiation reflectivity of the thermochromic layer changes linearly between 25 °C and 35 °C.

2. The thermochromic retroreflective composite material according to claim 1, wherein the thermochromic layer is formed by a thermochromic coating, and the thermochromic coating is a thermochromic ink 1011.

3. The thermochromic retroreflective composite material according to claim 1, wherein when the reflector is the prism cone, the partial embedding refers to embedding of other parts of the reflector except an upper surface in the thermochromic layer; andwhen the reflector is the glass bead, the partial embedding refers to embedding of 40-60% of a height of the reflector in the thermochromic layer.

4. The thermochromic retroreflective composite material according to claim 1 or 3, wherein the reflector comprises a reflector with a transparent resin coating layer.

5. The thermochromic retroreflective composite material according to claim 4, wherein the transparent resin coating layer has a thickness of 0.1-0.3 mm.

6. The thermochromic retroreflective composite material according to claim 1 or 3, wherein the prism cone has a stereoscopic acceptance angle of 45-55° and a height of 0.4-0.6 mm.

7. The thermochromic retroreflective composite material according to claim 1 or 3, wherein the glass bead has a particle size of 0.1-0.6 mm.

8. The thermochromic retroreflective composite material according to claim 1, 2, 3, or 5, further comprising a transparent resin layer on a surface of thermochromic retroreflective layer.

9. Use of the thermochromic retroreflective composite material according to any one of claims 1 to 8 in a construction industry.10 09 24

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