A temperature-changing color car film and preparation method thereof

Abstract

The present invention relates to the field of polyurethane materials, and specifically to a temperature-changing color car film and a preparation method thereof. The present invention first uses polyurethane to encapsulate vanadium dioxide powder to obtain color-changing microcapsules; then 1,1,1,3,5,5,5-heptamethyltrisiloxane and 3-allyloxy-1,2-propylene glycol are used as raw materials to synthesize organosilicon-modified diols, and trimellitic anhydride and toluene diisocyanate are reacted to synthesize dicarboxylic imide compounds; the organosilicon-modified diols and dicarboxylic imide compounds are subjected to esterification and polymerization to obtain organosilicon-modified imide polyester diols, which are then mixed with polytetramethylene glycol 2000, and then reacted with toluene diisocyanate to obtain a polyurethane elastomer. The polyurethane elastomer, color-changing microcapsules, silane coupling agent, plasticizer, antioxidant, and ultraviolet light absorber are mixed, melt-extruded, and blown into a film to obtain a temperature-changing color car film.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane materials, in particular to a temperature-changing color vehicle film and a preparation method thereof. Background Art

[0002] Car film is a thin film pasted on the front and rear windshields, side windows and sunroof of the vehicle, also known as solar film or heat insulation film. Its main function is to block ultraviolet rays, block some heat, prevent glass from splashing and injuring people, and prevent glare. At the same time, based on the one-way perspective performance of the solar film, it can protect personal privacy. In addition, it can also reduce damage to items and people in the car caused by ultraviolet radiation, reduce the temperature inside the car through physical reflection, reduce the use of car air conditioning, reduce fuel consumption, and be economical and environmentally friendly.

[0003] Compared with the heat insulation and one-way perspective functions of traditional car films, more and more companies are currently committed to developing temperature-changing car films. At present, the method of preparing temperature-changing film is relatively simple, usually preparing temperature-changing microcapsules first, and then directly applying the prepared temperature-changing microcapsules on the polyurethane film to obtain the temperature-changing car film. However, in this method, due to the presence of the wall material of the color-changing microcapsules, it is easy to cause the surface of the polyurethane film to become white and foggy, and the color-changing microcapsule coating falls off, resulting in a poor color-changing effect, so it needs to be improved. Summary of the invention

[0004] The object of the present invention is to provide a temperature-changing color vehicle film and a preparation method thereof to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a temperature-changing color car film and a preparation method thereof, comprising the following steps:

[0006] Step 1:

[0007] S11: Add acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4-4.2, then add KH550, stir for 1-2 hours, add vanadium dioxide powder, heat to 60-65°C, react for 3-5 hours, centrifuge and dry to obtain modified vanadium dioxide powder;

[0008] S12: Adding gum arabic powder to deionized water, stirring evenly to prepare an emulsifier solution, mixing the modified vanadium dioxide powder with the emulsifier solution, stirring and emulsifying for 10-15 minutes in a water bath at 60-65° C., and stirring at a speed of 10000-12000 rpm to obtain a core material dispersion; mixing polytetramethylene glycol 2000 and toluene diisocyanate, reacting at 60-70° C. for 2-3 hours to obtain a shell material;

[0009] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, using dibutyltin dilaurate as a catalyst, stirring and reacting at 60-70° C. for 1-2 hours to obtain a color-changing microcapsule;

[0010] Step 2:

[0011] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution of 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 1-2 hours, and the reaction temperature during the dropping is 100-110°C; after the dropping is completed, the reaction is continued to be kept warm for 2-3 hours to obtain a silicone-modified diol;

[0012] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are mixed and dispersed in N-methylpyrrolidone, stirred at 75-85° C. for 0.5 h, heated to 115-125° C. and stirred for 1-2 h to obtain a dicarboxylic imide compound;

[0013] S23: mixing a dicarboxylic imide compound with an organosilicon-modified diol, using monobutyltin oxide as a catalyst, reacting at 150-160° C. for 2-3 hours to obtain an organosilicon-modified imide polyester diol;

[0014] Step 3:

[0015] S31: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 to obtain a mixed diol; adding toluene diisocyanate to the mixed diol under a nitrogen environment, raising the temperature to 60-70° C., and reacting for 3-4 hours; lowering the temperature to 40-50° C., adding chain extender 1,4-butanediol and dibutyltin dilaurate, and reacting at 60-70° C. for 1-2 hours to obtain a polyurethane elastomer;

[0016] S32: Mix polyurethane elastomer, color-changing microcapsules, silane coupling agent, plasticizer, antioxidant, and ultraviolet light absorber at 60-80°C, melt-extrude at 120-140°C, and blow mold into a film to obtain a temperature-changing car film.

[0017] Furthermore, in S11, the mass ratio of the ethanol aqueous solution, KH550, and the vanadium dioxide powder is 100:1:(2~4).

[0018] Furthermore, in S12, an emulsifier solution with a mass fraction of 3~5% is produced; in the core material dispersion, the mass ratio of modified vanadium dioxide powder to emulsifier solution is (5~8):100; in the shell material, the isocyanate content is 27~32% by weight.

[0019] Furthermore, in S13, the chain extension coefficient is 0.88~0.93; and the mass ratio of the shell material to the core material dispersion is 1:(12~16).

[0020] Furthermore, in S21, 1,1,1,3,5,5,5-heptamethyltrisiloxane and 3-allyloxy-1,2-propanediol are reacted in a molar ratio of 1:1.

[0021] Furthermore, in S22, trimellitic anhydride and toluene diisocyanate are reacted in a molar ratio of 2:1.

[0022] Furthermore, in S23, the dicarboxylic imide compound and the organosilicon-modified diol are mixed at a molar ratio of carboxyl group to hydroxyl group of 1:(1.2-1.5).

[0023] Furthermore, in S31, in the mixed diol, the mass ratio of the silicone-modified imide polyester diol to the polytetramethylene ether diol 2000 is 1:(5~10).

[0024] Furthermore, in S31, the amount of each component, by weight, is 65-85 parts of mixed diol, 28-43 parts of toluene diisocyanate, 5-8 parts of chain extender 1,4-butanediol, and 0.3-0.5 parts of dibutyltin dilaurate.

[0025] Furthermore, in S32, the amount of each component, by weight, is 100-120 parts of polyurethane elastomer, 5-8 parts of color-changing microcapsules, 1-2 parts of silane coupling agent, 1-2 parts of plasticizer, 0.5-0.8 parts of antioxidant, and 0.5-0.8 parts of ultraviolet light absorber.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the present invention uses vanadium dioxide as a thermochromic material. Under low temperature conditions, vanadium dioxide has good near-infrared light transmittance, which can effectively increase the temperature inside the car; under high temperature conditions, it reflects near-infrared radiation after phase change, blocking external heat from entering the car, and can keep the temperature inside the car at a lower level in hot summer. When preparing the car film, vanadium dioxide is added to the polyurethane elastomer, melt-extruded, and blown into a film to obtain the car film. Since vanadium dioxide powder is easy to agglomerate, the present invention first uses KH550 to modify it, and then wraps it with polyurethane to obtain color-changing microcapsules. Compared with vanadium dioxide powder, the color-changing microcapsules have better dispersibility, and the shell material of the microcapsules is the same as the raw material of the polyurethane matrix of the car film, and the two are more compatible after blending.

[0027] When preparing the polyurethane elastomer as a vehicle film matrix, the present invention uses 1,1,1,3,5,5,5-heptamethyltrisiloxane and 3-allyloxy-1,2-propylene glycol as raw materials, and obtains an organosilicon-modified diol through a silicon-hydrogen bond addition reaction; reacts trimellitic anhydride and toluene diisocyanate to obtain a dicarboxylic imide compound; esterifies and polymerizes the dicarboxylic imide compound and the organosilicon-modified diol to obtain an organosilicon-modified imide polyester diol; mixes the organosilicon-modified imide polyester diol with polytetramethylene glycol, and reacts the mixture with toluene diisocyanate as a soft segment to obtain a polyurethane elastomer. Since the organosilicon-modified imide polyester diol contains a large number of imide rings and ester groups, the presence of these groups can form intermolecular hydrogen bonds and improve the interaction between molecules, so the prepared car film has greater tensile strength and elongation at break; at the same time, the strong intermolecular interaction also makes it difficult for the molecular chain segments to move, so the volume loss is reduced and the wear resistance is improved. In addition, the presence of organosilicon-modified imide polyester diol introduces silicone into the side chain of the polyurethane molecule. Compared with the main chain long-chain silicone group, the short-chain silicone on the side chain is more likely to migrate and aggregate to the surface of the material, which can give the car film good hydrophobicity, water resistance and wear resistance without affecting the mechanical properties of the polyurethane elastomer. It should be added that the amount of organosilicon-modified imide polyester diol is not the more the better. When its amount is too high, the elongation at break of the material decreases and the toughness becomes worse. Therefore, it is controlled to be mixed with polytetrahydrofuran ether diol 2000 at a mass ratio of 1: (5~10) to prepare a better car film. The vehicle film prepared by the invention has good quality, is beautiful and practical, can change color after heating, has uniform color distribution without color difference, and has good mechanical properties, wear resistance and surface self-cleaning properties. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Materials and sources used in the present invention: vanadium dioxide powder comes from Hangzhou Jikang New Materials Co., Ltd., item number SS-V50; gum arabic powder comes from Aladdin Reagent (Shanghai) Co., Ltd.; polytetramethylene ether glycol 2000 comes from Jining Baiyi Chemical Co., Ltd.; silane coupling agent is vinyl triethoxysiloxane, plasticizer is di(2-ethylhexyl) phthalate, antioxidant is antioxidant 1010, and ultraviolet light absorber is UV-531, all from Aladdin Reagent (Shanghai) Co., Ltd.

[0030] Embodiment 1: A temperature-changing color car film and a preparation method thereof, comprising the following steps:

[0031] Step 1:

[0032] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 1 hour, adding vanadium dioxide powder, heating to 60°C, reacting for 3 hours, centrifuging and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550 and vanadium dioxide powder is 100:1:2;

[0033] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 10 minutes in a water bath at 60°C, and the stirring speed is 10000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 60°C for 2 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0034] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 60° C. for 1 h to obtain color-changing microcapsules; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0035] Step 2:

[0036] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 1 hour, and the reaction temperature during the dropping is 100°C; after the dropping is completed, the heat preservation reaction is continued for 2 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0037] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 75° C. for 0.5 h, heated to 115° C. and stirred for 1-2 h to obtain a dicarboxylic imide compound;

[0038] S23: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 150°C for 2h to obtain an organosilicon-modified imide polyester diol;

[0039] Step 3:

[0040] S31: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 at a mass ratio of 1:10 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, raising the temperature to 60° C., and reacting for 3 hours; cooling to 40° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting at 60° C. for 1 hour to obtain a polyurethane elastomer;

[0041] S32: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 60° C., melt-extruded at 120° C., and blown into a film to obtain a temperature-changing car film.

[0042] Embodiment 2: A temperature-changing color car film and a preparation method thereof, comprising the following steps:

[0043] Step 1:

[0044] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 1.5 hours, adding vanadium dioxide powder, heating to 65°C, reacting for 4 hours, centrifuging and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550 and vanadium dioxide powder is 100:1:2;

[0045] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 15 minutes in a water bath at 65°C, and the stirring speed is 11000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 65°C for 2.5 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0046] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 65° C. for 1.5 h to obtain a color-changing microcapsule; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0047] Step 2:

[0048] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 1.5 hours, and the reaction temperature during the dropping is 105°C; after the dropping is completed, the heat preservation reaction is continued for 2.5 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0049] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 80° C. for 0.5 h, heated to 120° C. and stirred for 1.5 h to obtain a dicarboxylic imide compound;

[0050] S23: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 155°C for 2.5h to obtain an organosilicon-modified imide polyester diol;

[0051] Step 3:

[0052] S31: Mixing silicone-modified imide polyester diol and polytetramethylene glycol 2000 in a mass ratio of 1:8 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, heating to 65° C., and reacting for 3.5 hours; cooling to 45° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting at 65° C. for 1.5 hours to obtain a polyurethane elastomer;

[0053] S32: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 70° C., melt-extruded at 130° C., and blown into a film to obtain a temperature-changing car film.

[0054] Embodiment 3: A temperature-changing color car film and a preparation method thereof, comprising the following steps:

[0055] Step 1:

[0056] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 2 hours, adding vanadium dioxide powder, heating to 65°C, reacting for 5 hours, centrifuging, and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550, and vanadium dioxide powder is 100:1:2;

[0057] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 10 minutes in a water bath at 60°C, and the stirring speed is 12000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 70°C for 3 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0058] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 70° C. for 2 h to obtain a color-changing microcapsule; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0059] Step 2:

[0060] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 2 hours, and the reaction temperature during the dropping is 110°C; after the dropping is completed, the reaction is continued to be kept warm for 3 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0061] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 85° C. for 0.5 h, heated to 125° C. and stirred for 2 h to obtain a dicarboxylic imide compound;

[0062] S23: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 160°C for 3h to obtain an organosilicon-modified imide polyester diol;

[0063] Step 3:

[0064] S31: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 at a mass ratio of 1:7 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, raising the temperature to 70° C., and reacting for 4 hours; cooling the mixture to 50° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting the mixture at 70° C. for 2 hours to obtain a polyurethane elastomer;

[0065] S32: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 80° C., melt-extruded at 140° C., and blown into a film to obtain a temperature-changing car film.

[0066] Embodiment 4: A temperature-changing color car film and a preparation method thereof, comprising the following steps:

[0067] Step 1:

[0068] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 2 hours, adding vanadium dioxide powder, heating to 65°C, reacting for 5 hours, centrifuging, and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550, and vanadium dioxide powder is 100:1:2;

[0069] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 15 minutes in a water bath at 65°C, and the stirring speed is 12000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 70°C for 3 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0070] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 70° C. for 2 h to obtain a color-changing microcapsule; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0071] Step 2:

[0072] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 2 hours, and the reaction temperature during the dropping is 110°C; after the dropping is completed, the reaction is continued to be kept warm for 3 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0073] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 85° C. for 0.5 h, heated to 125° C. and stirred for 2 h to obtain a dicarboxylic imide compound;

[0074] S23: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 160°C for 3h to obtain an organosilicon-modified imide polyester diol;

[0075] Step 3:

[0076] S31: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 at a mass ratio of 1:5 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, raising the temperature to 70° C., and reacting for 4 hours; cooling to 50° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting at 70° C. for 2 hours to obtain a polyurethane elastomer;

[0077] S32: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 80° C., melt-extruded at 140° C., and blown into a film to obtain a temperature-changing car film.

[0078] Comparative Example 1: Vanadium dioxide powder is directly blended with polyurethane elastomer, and the other parameters are the same as those in Example 1.

[0079] Step 1:

[0080] S11: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 1 hour, and the reaction temperature during the dropping is 100°C; after the dropping is completed, the heat preservation reaction is continued for 2 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0081] S12: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 75° C. for 0.5 h, heated to 115° C. and stirred for 1-2 h to obtain a dicarboxylic imide compound;

[0082] S13: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 150° C. for 2 h to obtain an organosilicon-modified imide polyester diol;

[0083] Step 2:

[0084] S21: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 at a mass ratio of 1:10 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, raising the temperature to 60° C., and reacting for 3 hours; cooling to 40° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting at 60° C. for 1 hour to obtain a polyurethane elastomer;

[0085] S22: 100 kg of polyurethane elastomer, 5 kg of vanadium dioxide powder, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 60° C., melt-extruded at 120° C., and blown into a film to obtain a temperature-changing car film.

[0086] Comparative Example 2: No silicone-modified imide polyester diol was added, and other parameters were the same as those in Example 2.

[0087] Step 1:

[0088] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 1.5 hours, adding vanadium dioxide powder, heating to 65°C, reacting for 4 hours, centrifuging and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550 and vanadium dioxide powder is 100:1:2;

[0089] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 15 minutes in a water bath at 65°C, and the stirring speed is 11000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 65°C for 2.5 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0090] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 65° C. for 1.5 h to obtain a color-changing microcapsule; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0091] Step 2:

[0092] S21: Under nitrogen environment, add 36 kg of toluene diisocyanate to 75 kg of polytetramethylene glycol 2000, raise the temperature to 65° C., and react for 3.5 hours; cool to 45° C., add 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and react at 65° C. for 1.5 hours to obtain a polyurethane elastomer;

[0093] S22: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 70° C., melt-extruded at 130° C., and blown into a film to obtain a temperature-changing car film.

[0094] Comparative Example 3: The amount of the organosilicon-modified imide polyester diol was increased, and the other parameters were the same as those in Example 3.

[0095] Step 1:

[0096] S11: adding acetic acid to a 90% ethanol aqueous solution to adjust the pH to 4.2, then adding KH550, stirring for 2 hours, adding vanadium dioxide powder, heating to 65°C, reacting for 5 hours, centrifuging, and drying to obtain modified vanadium dioxide powder; wherein the mass ratio of ethanol aqueous solution, KH550, and vanadium dioxide powder is 100:1:2;

[0097] S12: Add gum arabic powder to deionized water, stir evenly to prepare an emulsifier solution with a mass fraction of 5%, mix the modified vanadium dioxide powder with the emulsifier solution, stir and emulsify for 10 minutes in a water bath at 60°C, and the stirring speed is 12000rpm to obtain a core material dispersion; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is 5:100; mix polytetramethylene glycol 2000 and toluene diisocyanate, react at 70°C for 3 hours to obtain a shell material; in the shell material, the isocyanate content is 30% by weight;

[0098] S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, with a chain extension coefficient of 0.91, using dibutyltin dilaurate as a catalyst, stirring and reacting at 70° C. for 2 h to obtain a color-changing microcapsule; wherein the mass ratio of the shell material to the core material dispersion is 1:12;

[0099] Step 2:

[0100] S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution containing 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 2 hours, and the reaction temperature during the dropping is 110°C; after the dropping is completed, the reaction is continued to be kept warm for 3 hours to obtain an organosilicon-modified diol; wherein the molar ratio of 1,1,1,3,5,5,5-heptamethyltrisiloxane to 3-allyloxy-1,2-propylene glycol is 1:1;

[0101] S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are dispersed in N-methylpyrrolidone in a molar ratio of 2:1, stirred at 85° C. for 0.5 h, heated to 125° C. and stirred for 2 h to obtain a dicarboxylic imide compound;

[0102] S23: mixing a dicarboxylic imide compound and an organosilicon-modified diol at a carboxyl group to hydroxyl group molar ratio of 1:1.2, using monobutyltin oxide as a catalyst, reacting at 160°C for 3h to obtain an organosilicon-modified imide polyester diol;

[0103] Step 3:

[0104] S31: mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 in a mass ratio of 1:3 to obtain a mixed diol; adding 36 kg of toluene diisocyanate to 75 kg of the mixed diol under a nitrogen environment, raising the temperature to 70° C., and reacting for 4 hours; cooling to 50° C., adding 5 kg of chain extender 1,4-butanediol and 0.5 kg of dibutyltin dilaurate, and reacting at 70° C. for 2 hours to obtain a polyurethane elastomer;

[0105] S32: 100 kg of polyurethane elastomer, 5 kg of color-changing microcapsules, 1 kg of silane coupling agent, 1 kg of plasticizer, 0.5 kg of antioxidant, and 0.5 kg of ultraviolet light absorber are mixed at 80° C., melt-extruded at 140° C., and blown into a film to obtain a temperature-changing car film.

[0106] Experiment: The performance of the temperature-changing color car films in Examples 1 to 4 and Comparative Examples 1 to 3 was tested, wherein:

[0107] Color change performance: Put the sample into an oven, heat it from room temperature to 50°C for 30 minutes, keep it warm for 60 minutes, then take it out and observe the color change effect of the sample.

[0108] Mechanical properties: With reference to the standard GB / T 528-2009, the tensile strength and elongation at break were measured using a tensile testing machine; the gauge length of the specimen was 10 mm and the tensile rate was 100 mm / min.

[0109] Wear resistance: Referring to the standard GB / T 9867-2008, the wear resistance of the sample was characterized by the rotating roller abrasion machine method, and the density A (g / cm3), the three average mass loss of the test piece ΔV (g), the three average wear of the standard rubber ΔW (g), the volume loss value Δ (mm 3 ) is calculated as follows:

[0110] Δ=(ΔV×200) / (ΔW×A).

[0111] Hydrophobic performance: A contact angle analyzer was used to test the contact angle between the sample and the water surface.

[0112]

[0113] Conclusion: The data of Examples 1 to 4 show that the car film prepared by the present invention can change color after heating, and the color distribution is uniform and has no color difference, and has good mechanical properties, wear resistance and surface self-cleaning properties. The data of Example 1 and Comparative Example 1 show that compared with the direct addition of modified vanadium dioxide powder, the color-changing microcapsules have better dispersion in the car film; the data of Example 2 and Comparative Example 2 show that the car film in Example 2 has stronger mechanical properties, is more wear-resistant, and has a certain self-cleaning function; the data of Example 3 and Comparative Example 3 show that after increasing the amount of organosilicon-modified imide polyester diol, the elongation at break of the car film material is significantly reduced.

[0114] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a temperature-changing color film for a vehicle, characterized in that: The following steps are involved: Step 1: S11: add acetic acid to the ethanol aqueous solution to adjust the pH to 4-4.2, add KH550 and stir for 1-2 hours, add vanadium dioxide powder, heat to 60-65°C, react for 3-5 hours, centrifuge and dry to obtain modified vanadium dioxide powder; S12: Adding gum arabic powder to deionized water, stirring to prepare an emulsifier solution, mixing the modified vanadium dioxide powder with the emulsifier solution, stirring and emulsifying for 10-15 minutes in a water bath at 60-65° C., and a stirring speed of 10000-12000 rpm to obtain a core material dispersion; mixing polytetramethylene glycol 2000 and toluene diisocyanate, reacting at 60-70° C. for 2-3 hours to obtain a shell material; S13: mixing the shell material and the core material dispersion, adding a chain extender 1,4-butanediol, using dibutyltin dilaurate as a catalyst, stirring and reacting at 60-70° C. for 1-2 hours to obtain a color-changing microcapsule; Step 2: S21: 1,1,1,3,5,5,5-heptamethyltrisiloxane, polymerization inhibitor phenothiazine, and Karstedt catalyst are dispersed in xylene, and a xylene mixed solution of 3-allyloxy-1,2-propylene glycol is added dropwise, and the dropping time is controlled to be 1-2 hours, and the reaction temperature during the dropping is 100-110°C; after the dropping is completed, the reaction is continued to be kept warm for 2-3 hours to obtain a silicone-modified diol; S22: Under a nitrogen environment, trimellitic anhydride and toluene diisocyanate are mixed and dispersed in N-methylpyrrolidone, stirred at 75-85° C. for 0.5 h, heated to 115-125° C. and stirred for 1-2 h to obtain a dicarboxylic imide compound; S23: mixing a dicarboxylic imide compound with an organosilicon-modified diol, using monobutyltin oxide as a catalyst, reacting at 150-160° C. for 2-3 hours to obtain an organosilicon-modified imide polyester diol; Step 3: S31: Mixing organosilicon-modified imide polyester diol and polytetramethylene glycol 2000 to obtain a mixed diol; adding toluene diisocyanate to the mixed diol under a nitrogen environment, heating to 60-70°C, and reacting for 3-4 hours; cooling to 40-50°C, adding chain extender 1,4-butanediol and dibutyltin dilaurate, and reacting at 60-70°C for 1-2 hours to obtain a polyurethane elastomer; wherein the amount of each component, by weight, is 65-85 parts of mixed diol, 28-43 parts of toluene diisocyanate, 5-8 parts of chain extender 1,4-butanediol, and 0.3-0.5 parts of dibutyltin dilaurate; in the mixed diol, the mass ratio of organosilicon-modified imide polyester diol to polytetramethylene glycol 2000 is 1:(5-10); S32: Mix polyurethane elastomer, color-changing microcapsules, silane coupling agent, plasticizer, antioxidant, and ultraviolet light absorber at 60-80°C, melt-extrude at 120-140°C, and blow mold into a film to obtain a temperature-changing car film.

2. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S11, the mass ratio of ethanol aqueous solution, KH550, and vanadium dioxide powder is 100:1:(2~4).

3. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S12, the mass concentration of the emulsifier solution is 3~5%; in the core material dispersion, the mass ratio of the modified vanadium dioxide powder to the emulsifier solution is (5~8):100; in the shell material, the isocyanate content is 27~32% by weight.

4. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S13, the chain extension coefficient is 0.88~0.93; the mass ratio of shell material to core material dispersion is 1:(12~16).

5. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S21, 1,1,1,3,5,5,5-heptamethyltrisiloxane and 3-allyloxy-1,2-propanediol are reacted in a molar ratio of 1:

1.

6. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S22, trimellitic anhydride and toluene diisocyanate are reacted in a molar ratio of 2:

1.

7. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S23, the dicarboxylic imide compound and the organosilicon-modified diol are mixed at a molar ratio of carboxyl group to hydroxyl group of 1:(1.2-1.5).

8. The method for preparing a temperature-changing color vehicle film according to claim 1, characterized in that: In S32, the amount of each component, by weight, is 100-120 parts of polyurethane elastomer, 5-8 parts of color-changing microcapsules, 1-2 parts of silane coupling agent, 1-2 parts of plasticizer, 0.5-0.8 parts of antioxidant, and 0.5-0.8 parts of ultraviolet light absorber.

9. The temperature-changing color vehicle film prepared by the preparation method according to any one of claims 1 to 8.

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