Temperature-sensitive color-changing coating and preparation method thereof

Abstract

The invention discloses a temperature-sensitive color-changing coating and a preparation method thereof. The temperature-sensitive color-changing coating comprises the following components in parts by weight: 10-35 parts of matrix resin; 0.5 to 15 parts of a microcapsule body; 25 to 40 parts of a mixed solvent; wherein the microcapsule body comprises 0.1-5 parts of a color indicator, 0.1-8 parts of a phase-change material, and 0.3-8 parts of a wall material, the phase-change temperature range of the phase-change material is 25-60 DEG C. The temperature-sensitive color-changing coating provided by the invention has a wider color-changing temperature range and a remarkable color-changing effect, so that a better visual effect can be presented, and the temperature-sensitive color-changing coating can be applied to the field of temperature-sensitive color-changing coatings. And therefore, a more visual and striking indication or warning effect can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of color-changing materials, and further to a temperature-sensitive color-changing coating and a preparation method thereof. Background Art

[0002] With the advancement of science and technology and the improvement of people's quality of life, the demand for intelligent and multifunctional materials is increasing. Traditional materials are mostly fixed in color performance and cannot meet the needs of modern technology products in visual interaction, environmental monitoring and other aspects. As an emerging functional material, thermochromic coatings can realize automatic color conversion by sensing subtle changes in ambient temperature and have important application value. However, thermochromic coatings on the market currently generally have problems such as narrow color change range, unclear color change, slow response speed and poor durability, which limits their wide application.

[0003] Therefore, it is urgent to develop a temperature-sensitive color-changing coating to solve the above-mentioned technical problems. Summary of the invention

[0004] In view of the above technical problems, the object of the present invention is to provide a temperature-sensitive color-changing coating, which can solve the problems raised in the above background technology.

[0005] In order to achieve the above object, the present invention provides a temperature-sensitive color-changing coating, comprising the following components in parts by weight:

[0006] Main resin 10-35 parts;

[0007] Microcapsules 0.5-15 parts;

[0008] 25-40 parts of mixed solvent;

[0009] The microcapsule comprises 0.1-5 parts of a color indicator, 0.1-8 parts of a phase change material, the phase change temperature range of the phase change material is 25° C.-60° C., and 0.3-8 parts of a wall material.

[0010] The temperature-sensitive color-changing paint with the above components has a wider color-changing temperature range and a significant color-changing effect, so as to present a better visual effect, and thus can play a more intuitive and eye-catching indication or warning role.

[0011] In some embodiments, the phase change material is a mixture of stearic acid and palmitic acid, wherein the mass ratio of the stearic acid to the palmitic acid is 1:2-1:4.

[0012] By setting the phase change material to a mixture of stearic acid and palmitic acid, wherein the mass ratio of the stearic acid to the palmitic acid is 1:2-1:4, a faster response speed can be achieved, thereby effectively improving the color change efficiency, effectively improving the performance of the product, and enhancing the user experience.

[0013] In some embodiments, the wall material is polymethyl methacrylate or gelatin-gum arabic composite.

[0014] By setting the wall material to polymethyl methacrylate or gelatin-gum arabic composite, a basis is provided for the stability and rapid release performance of the microcapsules, and the cost of the coating provided in the present application is effectively reduced, thereby effectively improving the practicality and reliability of the coating provided in the present application.

[0015] In some embodiments, the microcapsules are made by microemulsion polymerization.

[0016] The microcapsules are made by microemulsion polymerization so that the particle size of the microcapsules is small and uniform, which is beneficial to the uniform distribution of the microcapsules in the coating. In addition, the microemulsion polymerization reaction is carried out in tiny droplets to form a dense and continuous capsule wall, which has good wrapping properties for the core material and can effectively prevent the core material from leaking.

[0017] In some embodiments, the color indicator is encapsulated by the phase change material and the matrix resin by a blending method to form the microcapsule;

[0018] Alternatively, the color indicator is implanted into the microcapsule by adsorption.

[0019] The color indicator is placed in the microcapsule by a blending method or an adsorption method, so that the wall material of the microcapsule can provide physical protection for the color indicator, thereby protecting it from external environmental factors such as oxygen, moisture, ultraviolet rays, etc., reducing oxidation, hydrolysis or photodegradation reactions of the indicator, thereby improving its stability. In addition, the release rate of the color indicator can also be effectively controlled, effectively improving the sensitivity of the color indicator.

[0020] In some embodiments, the color indicator is a red indicator and a blue indicator.

[0021] In some embodiments, the microcapsules are mixed with the host resin by any one of mechanical stirring, ultrasonic dispersion, and ball milling.

[0022] The microcapsules and the main resin are mixed by mechanical stirring, ultrasonic dispersion and ball milling to effectively break the agglomeration effect of the microcapsules, so that the microcapsules can be evenly dispersed in the main resin, effectively ensuring the quality and use effect of the coating.

[0023] In some embodiments, the functional auxiliary agent is any combination of a dispersant, a stabilizer, and a surfactant.

[0024] By setting functional additives composed of any combination of dispersants, stabilizers, and surfactants, the durability of coating products can be effectively improved, thereby effectively improving the practicality and reliability of the products to meet a wider range of application needs.

[0025] According to another aspect of the invention, the present invention further provides a preparation method for preparing the temperature-sensitive color-changing coating as described in any of the above embodiments, comprising the following steps:

[0026] S1, making phase change material and wall material into microcapsules;

[0027] S2, implanting a color indicator into the microcapsule by an adsorption method or a blending method;

[0028] S3, adding a mixed solvent into a stirring device, then adding the main resin and the microcapsules into the mixed solvent while stirring, and mixing them thoroughly to obtain the temperature-sensitive color-changing coating.

[0029] In some embodiments, the stirring speed of the stirring device is 1300-2500 rpm, and the stirring time is 30-50 minutes.

[0030] By setting the stirring speed of the stirring device to 1300-2500 rpm and the stirring time to 30-50 minutes, the microcapsules can be effectively prevented from agglomerating, so that the microcapsules can be evenly dispersed in the main resin, and the damage to the properties of the microcapsules and the resin itself can be effectively avoided, thereby providing a guarantee for the stability of the final coating product quality.

[0031] Compared with the prior art, the temperature-sensitive color-changing coating provided by the present invention has the following beneficial effects:

[0032] 1. The temperature-sensitive color-changing paint provided by the present invention has a wider color-changing temperature range and a significant color-changing effect, so as to present a better visual effect, and thus can play a more intuitive and eye-catching indication or warning role.

[0033] 2. The temperature-sensitive color-changing coating provided by the present invention achieves a faster response speed by setting the phase change material to a mixture of stearic acid and palmitic acid, wherein the mass ratio of the stearic acid to the palmitic acid is 1:2-1:4, thereby effectively improving the color change efficiency, effectively improving the performance of the product, and enhancing the user experience.

[0034] 3. The temperature-sensitive color-changing paint provided by the present invention effectively improves the durability of the paint product by setting a functional additive composed of any combination of a dispersant, a stabilizer, and a surfactant, thereby effectively improving the practicality and reliability of the product to meet a wider range of application needs. DETAILED DESCRIPTION

[0036] In one embodiment, a temperature-sensitive color-changing coating provided by the present invention includes the following components in parts by weight: 10-35 parts of a main resin; 0.5-15 parts of a microcapsule body; 25-40 parts of a mixed solvent; wherein the microcapsule body includes 0.1-5 parts of a color indicator, 0.1-8 parts of a phase change material, the phase change temperature range of the phase change material is 25°C-60°C, and 0.3-8 parts of a wall material.

[0037] Specifically, the temperature-sensitive color-changing paint provided by the present invention can be applied to furniture, accessories, and automobiles. For example, when the temperature-sensitive color-changing paint provided by the present invention is applied to mobile lamps, the mobile lamps can usually be touched with bare hands for carrying and use. When the surface temperature of the mobile lamp rises due to internal circuit short circuit, excessive bulb power, etc., and gradually approaches and exceeds 60°C, during this heating process, the surface color of the mobile lamp gradually changes from blue to red, thereby achieving the effect of warning the user to avoid burns.

[0038] In one embodiment, based on the above embodiment, the phase change material is a mixture of stearic acid and palmitic acid, wherein the mass ratio of stearic acid to palmitic acid is 1:2-1:4.

[0039] Specifically, the melting point of stearic acid is about 69-71°C, and the melting point of palmitic acid is about 62-63°C. When the two are mixed, a eutectic system is formed, and the phase transition temperature of the mixture is lower than the melting points of the two, and is significantly affected by the mixing ratio, so that the mixing ratio can be controlled according to actual needs to adjust the melting point of the mixture. After multiple ratio tests, it can be known that when the mass ratio of stearic acid to palmitic acid is about 1:3.5, the phase transition temperature of the mixture can fall within the range of 30-50°C. At this time, the thermal properties of the mixture are relatively stable, and can meet the requirements of the phase transition temperature of 25-60°C in the present invention.

[0040] It should be noted that the phase change material can also be a carbon chain length of C 18 The paraffin material can also be a carbon chain length of C 20 The paraffin material can also be other phase change materials that can meet the phase change temperature of 25-60°C. The specific material composition depends on actual needs and is not limited here.

[0041] In one embodiment, based on the above embodiment, the wall material is polymethyl methacrylate or gelatin-gum arabic composite.

[0042] Specifically, polymethyl methacrylate has good tensile strength, impact resistance, chemical stability and thermal stability, and gelatin-gum arabic composite has good stability, adjustability and film-forming properties, so both can be used to make the wall material of microcapsules. By setting the wall material to polymethyl methacrylate or gelatin-gum arabic composite, a basis is provided for the stability and rapid release performance of the microcapsules, and the cost of the coating provided in the present application is effectively reduced, thereby effectively improving the practicality and reliability of the coating provided in the present application.

[0043] In one embodiment, based on the above embodiment, the microcapsules are prepared by microemulsion polymerization.

[0044] Specifically, the microcapsules are made by microemulsion polymerization so that the particle size of the microcapsules is small and uniform, which is beneficial to the uniform distribution of the microcapsules in the coating. In addition, the microemulsion polymerization reaction is carried out in tiny droplets to form a dense and continuous capsule wall, which has good wrapping properties for the core material and can effectively prevent the core material from leaking.

[0045] In one embodiment, the color indicator is encapsulated by the phase change material and the matrix resin by a blending method to form a microcapsule; or the color indicator is implanted into the microcapsule by an adsorption method.

[0046] Specifically, the blending method is to mix the color indicator and phase change material thoroughly and evenly, and then wrap them together through a microencapsulation process, so that the color indicator is embedded in the interior of the microcapsule, while the adsorption method is to use the adsorption characteristics of the microcapsule wall material to adsorb the color indicator on the inner surface or internal pores of the microcapsule wall material. For example, when using gelatin-gum arabic composite wall material to make microcapsules, the microcapsules are first prepared and then immersed in a buffer solution containing the color indicator. Under appropriate temperature and time conditions, the color indicator will be adsorbed into the interior of the microcapsule. The color indicator is placed in the microcapsule by the blending method or the adsorption method, so that the wall material of the microcapsule can provide physical protection for the color indicator, so that it is protected from external environmental factors such as oxygen, moisture, ultraviolet rays, etc., and reduce the oxidation, hydrolysis or photodegradation reactions of the indicator, thereby improving its stability. In addition, it can also effectively control the release rate of the color indicator and effectively improve the sensitivity of the color indicator.

[0047] In one embodiment, based on the above embodiment, the color indicator is a red indicator and a blue indicator.

[0048] Specifically, the red indicator and the blue indicator can be a combination of acid-base indicator types, such as a phenolphthalein-bromocresol green combination and a methyl red-thymol blue combination. When the reaction system is set as a temperature-sensitive chemical system, the pH value in the reaction system can increase or decrease with changes in temperature, thereby achieving a corresponding color conversion of the color indicator. The red indicator and the blue indicator can also be complexes of metal ions such as cobalt or copper.

[0049] In one embodiment, based on the above embodiment, the microcapsules are mixed with the host resin by any one of mechanical stirring, ultrasonic dispersion and ball milling.

[0050] Specifically, mechanical stirring, ultrasonic dispersion and ball milling can all effectively break the agglomeration effect of microcapsules, thereby enabling the microcapsules to be evenly dispersed in the main resin. Mechanical stirring generates shear force through the rotation of the stirring paddle to evenly disperse the microcapsules in the main resin; ultrasonic dispersion utilizes the cavitation effect of ultrasonic waves to form tiny bubbles in the resin and burst them instantly. The impact force generated disperses the microcapsules, thereby enabling the microcapsules to be evenly dispersed in the main resin; ball milling is to evenly distribute the microcapsules in the main resin through the collision and friction of the ball milling medium with the microcapsules and the resin, and the evenly dispersed microcapsules form a stable system in the main resin, which is not prone to precipitation or stratification, thereby ensuring the quality and use effect of the coating.

[0051] In one embodiment, the functional auxiliary agent is any combination of a dispersant, a stabilizer, and a surfactant.

[0052] Specifically, dispersants are mainly used to reduce the mutual attraction between microcapsule particles, prevent microcapsule particles from agglomerating, and effectively reduce the friction between microcapsules and surrounding media, thereby making microcapsules have better fluidity; stabilizers are used to maintain and strengthen the morphology and structural stability of microcapsules, thereby effectively avoiding the interaction between microcapsules and other components, resulting in performance degradation or precipitation, stratification, etc.; surfactants are mainly used to reduce the surface tension between microcapsules and surrounding media, thereby making microcapsules more easily dispersed and stably present in the medium, and at the same time can adjust the permeability of the microcapsule shell membrane, thereby controlling the release rate and release time of the core material, and realizing precise regulation of the function of microcapsules. By adding functional additives composed of any combination of dispersants, stabilizers, and surfactants to microcapsules, the microcapsules have better stability and overall performance. This effectively improves the practicality and reliability of the coating.

[0053] According to another aspect of the invention, the present invention further provides a preparation method for preparing the temperature-sensitive color-changing coating as in any of the above embodiments, comprising the following steps:

[0054] S1, making phase change material and wall material into microcapsules;

[0055] S2, implanting the color indicator into the microcapsule by adsorption method or blending method;

[0056] S3. Add a mixed solvent into a stirring device, then add the main resin and microcapsules into the mixed solvent while stirring, and mix them thoroughly to obtain a temperature-sensitive color-changing coating.

[0057] Specifically, through the above steps, the temperature-sensitive color-changing coating provided in one embodiment of the present application can be obtained.

[0058] In one embodiment, based on the above embodiment, the stirring speed of the stirring device is 1300-2500 rpm, and the stirring time is 30-50 minutes.

[0059] Specifically, by setting the stirring speed of the stirring device to 1300-2500 rpm and the stirring time to 30-50 minutes, the microcapsules can be effectively prevented from agglomerating, so that the microcapsules can be evenly dispersed in the main resin, and the damage to the properties of the microcapsules and the resin itself can be effectively avoided, thereby providing a guarantee for the stability of the product quality of the final coating.

[0060] It should be noted that the above embodiments can be freely combined as needed. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A temperature-sensitive color-changing paint, characterized in that: The composition comprises the following components in parts by weight: Main resin 10-35 parts; Microcapsules 0.5-15 parts; 25-40 parts of mixed solvent; Functional additives 0.1-1 part; The microcapsule comprises 0.1-5 parts of a color indicator, 0.1-8 parts of a phase change material, the phase change temperature range of the phase change material is 25° C.-60° C., and 0.3-8 parts of a wall material.

2. The temperature-sensitive color-changing paint according to claim 1, characterized in that: The phase change material is a mixture of stearic acid and palmitic acid, wherein the mass ratio of the stearic acid to the palmitic acid is 1:2-1:

4.

3. The temperature-sensitive color-changing paint according to claim 2, characterized in that: The wall material is polymethyl methacrylate or gelatin-arabic gum composite.

4. The temperature-sensitive color-changing paint according to claim 3, characterized in that: The microcapsules are prepared by microemulsion polymerization.

5. The temperature-sensitive color-changing paint according to any one of claims 1 to 4, characterized in that: The color indicator is encapsulated by the phase change material and the matrix resin by a blending method to form the microcapsule; Alternatively, the color indicator is implanted into the microcapsule by adsorption.

6. The temperature-sensitive color-changing paint according to claim 5, characterized in that: The color indicators are a red indicator and a blue indicator.

7. The temperature-sensitive color-changing paint according to claim 6, characterized in that: The microcapsules are mixed with the main resin by any one of mechanical stirring, ultrasonic dispersion and ball milling.

8. The temperature-sensitive color-changing paint according to claim 6 or 7, characterized in that: The functional auxiliary agent is any combination of a dispersant, a stabilizer and a surfactant.

9. A preparation method for preparing the temperature-sensitive color-changing coating according to claims 1 to 8, characterized in that: The following steps are involved: S1, making phase change material and wall material into microcapsules; S2, implanting a color indicator into the microcapsule by an adsorption method or a blending method; S3, adding a mixed solvent into a stirring device, then adding the main resin and the microcapsules into the mixed solvent while stirring, and mixing them thoroughly to obtain the temperature-sensitive color-changing coating.

10. The preparation method according to claim 9, characterized in that: The stirring speed of the stirring device is 1300-2500 rpm, and the stirring time is 30-50 minutes.