Self-adaptive light-dimming temperature-control polyurethane protective film and preparation method thereof

Abstract

The invention discloses a self-adaptive light-dimming temperature-control polyurethane protective film and a preparation method thereof, and relates to the technical field of high polymer materials. When the self-adaptive light-dimming temperature-control polyurethane protective film is prepared, castor oil reacts with sulfhydrylated thiosemicarbazone to prepare modified castor oil; the preparation method comprises the following steps: carrying out ring opening polymerization on flame-retardant cyclotetrasiloxane and tetramethyl cyclotetrasiloxane to prepare a siloxane oligomer; enabling vanadium pentoxide, oxalic acid and tungstic acid to react to prepare tungsten-doped vanadium dioxide; the preparation method comprises the following steps: carrying out a reaction on tungsten-doped vanadium dioxide and allyltriethoxysilane to prepare modified vanadium dioxide; uniformly mixing castor oil, modified castor oil, siloxane oligomer, isophorone diisocyanate and copper chloride, pouring the mixture into a mold, and performing curing molding, so as to obtain the self-adaptive light-dimming temperature-control polyurethane protective film. The self-adaptive light-dimming temperature-control polyurethane protective film prepared by the invention has excellent flame retardance, tensile strength and self-adaptive light-dimming temperature-control performance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to an adaptive dimming and temperature-controlling polyurethane protective film and a preparation method thereof. Background Art

[0002] Ordinary building glass and car window glass have no selective permeability to sunlight. In summer, when sunlight passes through glass windows, its heat is also transferred into the room, causing the indoor temperature to rise, resulting in an increase in the load of air conditioning; while in winter, the indoor heat is dissipated outdoors, and the heating load also increases, resulting in a huge waste of energy. As automobile carbon emissions and high energy consumption in buildings are increasingly valued, the proportion of heating and cooling in total building energy consumption is gradually increasing. The huge automobile and building energy-saving market has driven the rapid growth of the smart glass window film market.

[0003] Sunlight is composed of about 5% ultraviolet rays, 43% visible light and 52% near infrared rays. The near infrared part, which accounts for 52%, is the culprit of indoor heat gain. Therefore, if you want to maximize the energy saving limit of glass, the control of the infrared part is an inevitable trend in the development of smart glass window film. Therefore, it is necessary to develop an adaptive dimming and temperature-control polyurethane protective film, and use this adaptive dimming and temperature-control polyurethane protective film as a new type of smart glass window film, which can block infrared rays when it is higher than room temperature, and restore the transmittance of infrared rays when it is lower than room temperature, and intelligently adjust the indoor temperature to achieve the effect of warm in winter and cool in summer and reduce energy consumption. Summary of the invention

[0004] The purpose of the present invention is to provide an adaptive dimming and temperature-controlling polyurethane protective film and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A self-adaptive dimming and temperature-controlling polyurethane protective film, wherein the self-adaptive dimming and temperature-controlling polyurethane protective film is prepared by reacting castor oil with thiosulfated thiosemicarbazone to obtain modified castor oil; ring-opening polymerization of flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane to obtain siloxane oligomer; tungsten-doped vanadium dioxide and allyl triethoxysilane to obtain modified vanadium dioxide; castor oil, modified castor oil, siloxane oligomer, isophorone diisocyanate and cupric chloride are uniformly mixed and poured into a mold for curing and forming, thereby preparing the self-adaptive dimming and temperature-controlling polyurethane protective film; The thiolated thiosemicarbazone is prepared by reacting 4-benzyl-3-thiosemicarbazone and mercaptoacetaldehyde; The flame retardant cyclotetrasiloxane is prepared by reacting heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide; The tungsten-doped vanadium dioxide is prepared by hydrothermal reaction with vanadium pentoxide as a raw material, oxalic acid as a reducing agent, and tungstic acid as a doping agent.

[0006] A method for preparing an adaptive dimming and temperature-controlling polyurethane protective film, the method for preparing the adaptive dimming and temperature-controlling polyurethane protective film comprising the following preparation steps: (1) Castor oil, thiosulfated thiosemicarbazone, azobisisobutyronitrile and toluene are mixed uniformly in a mass ratio of 1:(0.5-0.6):(0.03-0.05):(8-10), stirred at 70-80°C and 300-500 r / min for 3-4 h, and dried at 50-60°C under vacuum for 8-10 h to obtain modified castor oil; (2) Mix flame retardant cyclotetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide in a mass ratio of 1:(1.1-1.3):(0.01-0.03):(0.01-0.03), stir and react at 65-75°C and 300-500r / min for 20-30min, cool to room temperature, wash with an equal volume of deionized water and toluene, let stand to separate, remove the aqueous phase, repeat washing 3-5 times, take the organic phase and place it in a drying oven, dry it at 50-60°C under vacuum conditions for 8-10h to obtain a siloxane oligomer; (3) Add vanadium pentoxide and oxalic acid in a molar ratio of 1:2 to deionized water with a mass of 30 to 40 times the mass of vanadium pentoxide, then add tungstic acid with a mass of 0.5 to 0.6 times the mass of vanadium pentoxide, stir and react at 10 to 30°C and 300 to 500 r / min for 2 to 3 hours, place in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, hydrothermally react at 200 to 220°C for 60 to 70 hours, cool to room temperature, filter, wash with anhydrous ethanol and deionized water 3 to 5 times each, and under vacuum conditions, Dry at 70-80°C for 8-10 hours, calcine at high temperature, cool to room temperature, grind, and sieve to obtain tungsten-doped vanadium dioxide; mix tungsten-doped vanadium dioxide and anhydrous ethanol at a mass ratio of 1:(50-60) evenly, add silane hydrolyzate of 8-10 times the mass of tungsten-doped vanadium dioxide, stir at 50-60°C, 300-500r / min for 2-3 hours, filter, wash with anhydrous ethanol 3-5 times, and dry at 50-60°C for 8-10 hours under vacuum conditions to obtain modified vanadium dioxide; (4) Weigh 100-110 parts of castor oil, 180-200 parts of modified castor oil, 30-40 parts of siloxane oligomer, 200-210 parts of isophorone diisocyanate, 6-8 parts of cupric chloride, 2-3 parts of chloroplatinic acid, and 100-120 parts of butanone, mix them evenly, stir at 10-30°C and 300-500 r / min for 5-7 min, add 3-5 parts of dibutyltin dilaurate, continue stirring for 3-5 min, pour into a polytetrafluoroethylene mold, keep warm at 70-80°C for 3-4 h and at 50-60°C for 6-8 h under vacuum conditions, cool to room temperature and then demould to obtain an adaptive dimming and temperature-control polyurethane protective film.

[0007] As an optimization, the preparation method of the thiolated thiosemicarbazone in step (1) is: adding 4-benzyl-3-thiosemicarbazone and mercaptoacetaldehyde in a molar ratio of 1:1 to methanol with a mass 10 to 12 times that of 4-benzyl-3-thiosemicarbazone, stirring at 50 to 60°C and 300 to 500 r / min for 20 to 24 hours, and drying at 50 to 60°C for 8 to 10 hours under vacuum conditions to obtain the thiolated thiosemicarbazone; the reaction process is: .

[0008] As an optimization, the hydroxyl value of the castor oil in step (1) is 164 mg KOH / g.

[0009] As an optimization, the preparation method of the flame retardant cyclotetrasiloxane in step (2) is as follows: add heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide in a molar ratio of 1:1 to N,N-dimethylformamide with a mass of 8 to 10 times that of heptamethylcyclotetrasiloxane, add chloroplatinic acid with a mass of 0.03 to 0.05 times that of heptamethylcyclotetrasiloxane, stir and react at 70 to 80°C and 300 to 500 r / min for 2 to 3 hours, and dry at 50 to 60°C under vacuum conditions for 8 to 10 hours to obtain the flame retardant cyclotetrasiloxane.

[0010] As an optimization, the high temperature calcination conditions in step (3) are: calcination at 700-800°C for 5-6 hours under argon protection.

[0011] As an optimization, the screening in step (3) is through a 1000-1200 mesh sieve.

[0012] As an optimization, the preparation method of the silane hydrolyzate in step (3) is as follows: allyl triethoxysilane and anhydrous ethanol are uniformly mixed in a mass ratio of 1:(20-30), the pH value is adjusted to 4-6 with a 1 mol / L oxalic acid aqueous solution, and the mixture is stirred at 10-30° C. and 300-500 r / min for 50-60 min to prepare a silane hydrolyzate.

[0013] Compared with the prior art, the beneficial effects achieved by the present invention are: When preparing the self-adaptive dimming and temperature-controlling polyurethane protective film, the present invention comprises the following steps: reacting 4-benzyl-3-thiosemicarbazide and mercaptoacetaldehyde to obtain thiolated thiosemicarbazide; reacting castor oil with thiolated thiosemicarbazide to obtain modified castor oil; reacting heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide to obtain flame-retardant cyclotetrasiloxane; ring-opening polymerization of flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane to obtain siloxane oligomer; reacting vanadium pentoxide, oxalic acid and tungstic acid to obtain tungsten-doped vanadium dioxide; reacting tungsten-doped vanadium dioxide and allyltriethoxysilane to obtain modified vanadium dioxide; and uniformly mixing castor oil, modified castor oil, siloxane oligomer, isophorone diisocyanate and cupric chloride, and then pouring the mixture into a mold for curing and forming, so as to obtain the self-adaptive dimming and temperature-controlling polyurethane protective film.

[0014] Firstly, the amino group on 4-benzyl-3-thiosemicarbazide and the aldehyde group on mercaptoacetaldehyde undergo Schiff base reaction to obtain thiolated thiosemicarbazide, and a thiol group is introduced into the thiolated thiosemicarbazide; the carbon-carbon double bond on castor oil undergoes addition reaction with the thiol group on the thiolated thiosemicarbazide to obtain modified castor oil, and a thiosemicarbazide structure is introduced into the molecular chain of the modified castor oil. The thiosemicarbazide structure can react with copper chloride to generate a copper complex, which can destroy bacterial cell membranes and cell walls, interfere with the normal growth and reproduction process of bacteria, and cause bacterial death, thereby giving the adaptive dimming and temperature-control polyurethane protective film anti-mildew and antibacterial properties. At the same time, copper ions form coordination bonds with the thiosemicarbazide structure, increase the cross-linking sites of the system, inhibit the relative slip of the molecular chain, and give the adaptive dimming and temperature-control polyurethane protective film excellent mechanical properties.

[0015] Secondly, the Si-H bond on heptamethylcyclotetrasiloxane and the carbon-carbon double bond on 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide undergo a silylation reaction to obtain a flame-retardant cyclotetrasiloxane; the flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane are ring-opening polymerized to obtain a siloxane oligomer, and a DOPO structure and a Si-H bond are introduced into the molecular chain of the siloxane oligomer. The introduction of the DOPO structure can give the adaptive dimming and temperature-controlling polyurethane protective film excellent flame retardant properties. At the same time, the siloxane oligomer will form a dense barrier carbon layer with the polymer matrix at high temperature, which effectively prevents the transfer of heat and the diffusion of oxygen, and further improves the flame retardant effect; the Si-H bond introduced into the siloxane oligomer molecular chain can undergo a silylation reaction with the carbon-carbon double bond on castor oil and modified vanadium dioxide to form a cross-linked network, inhibit the relative slip between molecular chains, and improve the excellent mechanical properties of the adaptive dimming and temperature-controlling polyurethane protective film.

[0016] Finally, vanadium pentoxide, oxalic acid and tungstic acid are reacted to obtain tungsten-doped vanadium dioxide. Vanadium dioxide is a thermochromic material whose photoelectric properties vary greatly around the phase transition point of 68°C. When the external temperature is lower than the phase transition temperature of 68°C, vanadium dioxide is a semiconductor monoclinic structure with high infrared light transmittance. When the external temperature is higher than the phase transition temperature of 68°C, vanadium dioxide is a conductor rutile structure with low infrared light transmittance. In sunlight, near-infrared light, which accounts for 52%, is the culprit for indoor heat gain. Therefore, this property of vanadium dioxide can realize intelligent regulation of indoor temperature and has been applied in the field of smart windows. However, the phase transition temperature of vanadium dioxide, 68°C, is much higher than room temperature. In order to maximize the intelligent temperature regulation characteristics of vanadium dioxide, tungsten is doped into vanadium dioxide. The doped tungsten atoms replace part of the vanadium atoms, producing The defects cause tensile stress to be introduced into the vanadium dioxide lattice, thereby inducing lattice distortion. When a phase transition occurs, the d electron energy band of the outer layer of the vanadium atom overlaps at a lower temperature, which leads to a decrease in the phase transition temperature of vanadium dioxide. The phase transition of vanadium dioxide occurs at room temperature, which is more in line with people's needs for temperature regulation in the natural environment. Tungsten-doped vanadium dioxide and allyltriethoxysilane are reacted to obtain modified vanadium dioxide. Carbon-carbon double bonds are introduced into the modified vanadium dioxide to improve the compatibility of tungsten-doped vanadium dioxide with the matrix resin and avoid agglomeration. While giving full play to the intelligent temperature regulation effect of tungsten-doped vanadium dioxide, the carbon-carbon double bonds introduced into the modified vanadium dioxide can also undergo addition reaction with the Si-H bonds on the siloxane oligomers to form a cross-linked network, further improving the mechanical properties of the adaptive dimming and temperature-control polyurethane protective film. DETAILED DESCRIPTION

[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Example 1

[0018] A method for preparing an adaptive dimming and temperature-controlling polyurethane protective film, the method for preparing the adaptive dimming and temperature-controlling polyurethane protective film comprising the following preparation steps: (1) Add 4-benzyl-3-thiosemicarbazide and mercaptoacetaldehyde in a molar ratio of 1:1 to methanol with a mass that is 10 times that of 4-benzyl-3-thiosemicarbazide, stir and react at 50°C and 300 r / min for 24 hours, and dry at 50°C for 10 hours under vacuum conditions to obtain thiolated thiosemicarbazide; mix castor oil, thiolated thiosemicarbazide, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.5:0.03:8, stir and react at 70°C and 300 r / min for 4 hours, and dry at 50°C for 10 hours under vacuum conditions to obtain modified castor oil; (2) Heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide were added in a molar ratio of 1:1 to N,N-dimethylformamide (8 times the mass of heptamethylcyclotetrasiloxane), and 0.03 times the mass of heptamethylcyclotetrasiloxane was added with chloroplatinic acid, and the mixture was stirred at 70°C and 300 r / min for 3 h. The mixture was dried at 50°C for 10 h under vacuum to obtain flame retardant cyclotetrasiloxane. Tetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed uniformly in a mass ratio of 1:1.1:0.01:0.01, stirred at 65°C and 300r / min for 30min, cooled to room temperature, washed with an equal volume of deionized water and toluene, allowed to stand for stratification, the aqueous phase was removed, and the washing was repeated 3 times. The organic phase was placed in a drying oven and dried at 50°C for 10h under vacuum conditions to obtain a siloxane oligomer; (3) Vanadium pentoxide and oxalic acid were added to deionized water (30 times the mass of vanadium pentoxide) in a molar ratio of 1:2, and then tungstic acid (0.5 times the mass of vanadium pentoxide) was added, and the mixture was stirred at 10°C and 300 r / min for 3 hours. The mixture was placed in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 200°C for 70 hours. The mixture was cooled to room temperature, filtered, washed with anhydrous ethanol and deionized water for 3 times each, dried at 70°C for 10 hours under vacuum conditions, calcined at 700°C for 6 hours under argon protection, cooled to room temperature, ground, and sieved through a 1000-mesh sieve to obtain tungsten tungsten. Doping vanadium dioxide; allyl triethoxysilane and anhydrous ethanol were mixed evenly at a mass ratio of 1:20, the pH was adjusted to 4 with a 1 mol / L oxalic acid aqueous solution, and the mixture was stirred at 10°C and 300 r / min for 60 min to prepare a silane hydrolyzate; tungsten-doped vanadium dioxide and anhydrous ethanol were mixed evenly at a mass ratio of 1:50, silane hydrolyzate with a mass of 8 times that of tungsten-doped vanadium dioxide was added, and the mixture was stirred at 50°C and 300 r / min for 3 h, filtered, washed with anhydrous ethanol for 3 times, and dried at 50°C for 10 h under vacuum conditions to obtain modified vanadium dioxide; (4) Weigh 100 parts of castor oil, 180 parts of modified castor oil, 30 parts of siloxane oligomer, 200 parts of isophorone diisocyanate, 6 parts of cupric chloride, 2 parts of chloroplatinic acid, and 100 parts of butanone, mix them evenly, stir at 10°C and 300 r / min for 7 min, add 3 parts of dibutyltin dilaurate, continue stirring for 5 min, pour into a polytetrafluoroethylene mold, keep warm at 70°C for 4 h and at 50°C for 8 h under vacuum conditions, cool to room temperature and then demold, to obtain an adaptive dimming and temperature-controlling polyurethane protective film. Example 2

[0019] A method for preparing an adaptive dimming and temperature-controlling polyurethane protective film, the method for preparing the adaptive dimming and temperature-controlling polyurethane protective film comprising the following preparation steps: (1) Add 4-benzyl-3-thiosemicarbazide and mercaptoacetaldehyde in a molar ratio of 1:1 to methanol with a mass 11 times that of 4-benzyl-3-thiosemicarbazide, stir and react at 55°C and 400 r / min for 22 hours, and dry at 55°C for 9 hours under vacuum conditions to obtain thiolated thiosemicarbazide; mix castor oil, thiosemicarbazide, azobisisobutyronitrile and toluene in a mass ratio of 1:0.55:0.04:9, stir and react at 75°C and 400 r / min for 3.5 hours, and dry at 55°C for 9 hours under vacuum conditions to obtain modified castor oil; (2) Heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide were added in a molar ratio of 1:1 to N,N-dimethylformamide (9 times the mass of heptamethylcyclotetrasiloxane), and 0.04 times the mass of heptamethylcyclotetrasiloxane was added with chloroplatinic acid, and the mixture was stirred at 75°C and 400 r / min for 2.5 h. The mixture was dried at 55°C under vacuum for 9 h to obtain flame retardant cyclotetrasiloxane. Cyclotetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed uniformly in a mass ratio of 1:1.2:0.02:0.02, stirred at 70°C and 400r / min for 25min, cooled to room temperature, washed with an equal volume of deionized water and toluene, allowed to stand for stratification, the aqueous phase was removed, and the washing was repeated 4 times. The organic phase was placed in a drying oven and dried at 55°C for 9h under vacuum conditions to obtain a siloxane oligomer. (3) Vanadium pentoxide and oxalic acid were added to deionized water (35 times the mass of vanadium pentoxide) in a molar ratio of 1:2, and then tungstic acid (0.55 times the mass of vanadium pentoxide) was added, and the mixture was stirred at 20°C and 400 r / min for 2.5 h. The mixture was placed in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 210°C for 65 h. The mixture was cooled to room temperature, filtered, washed with anhydrous ethanol and deionized water for 4 times each, dried at 75°C under vacuum for 9 h, calcined at 750°C for 5.5 h under argon protection, cooled to room temperature, ground, and sieved through a 1100-mesh sieve to obtain Tungsten doped vanadium dioxide; allyl triethoxysilane and anhydrous ethanol were mixed evenly at a mass ratio of 1:25, the pH was adjusted to 5 with a 1 mol / L oxalic acid aqueous solution, and the mixture was stirred at 20°C and 400 r / min for 55 min to prepare a silane hydrolyzate; tungsten doped vanadium dioxide and anhydrous ethanol were mixed evenly at a mass ratio of 1:55, silane hydrolyzate with a mass of 9 times that of tungsten doped vanadium dioxide was added, and the mixture was stirred at 55°C and 400 r / min for 2.5 h, filtered, washed with anhydrous ethanol for 4 times, and dried at 55°C under vacuum for 9 h to obtain modified vanadium dioxide; (4) 105 parts of castor oil, 190 parts of modified castor oil, 35 parts of siloxane oligomer, 205 parts of isophorone diisocyanate, 7 parts of cupric chloride, 2.5 parts of chloroplatinic acid, and 110 parts of butanone were weighed and mixed evenly, and stirred at 20°C and 400 r / min for 6 min. 4 parts of dibutyltin dilaurate were added and stirred for 4 min. The mixture was poured into a polytetrafluoroethylene mold and kept at 75°C for 3.5 h and at 55°C for 7 h under vacuum conditions. The mixture was cooled to room temperature and then demolded to obtain an adaptive dimming and temperature-controlling polyurethane protective film. Example 3

[0020] A method for preparing an adaptive dimming and temperature-controlling polyurethane protective film, the method for preparing the adaptive dimming and temperature-controlling polyurethane protective film comprising the following preparation steps: (1) Add 4-benzyl-3-thiosemicarbazide and mercaptoacetaldehyde in a molar ratio of 1:1 to methanol (12 times the mass of 4-benzyl-3-thiosemicarbazide), stir and react at 60°C and 500 r / min for 20 hours, and dry at 60°C for 8 hours under vacuum conditions to obtain thiolated thiosemicarbazide; mix castor oil, thiosemicarbazide, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.6:0.05:10, stir and react at 80°C and 500 r / min for 3 hours, and dry at 60°C for 8 hours under vacuum conditions to obtain modified castor oil; (2) Heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide were added in a molar ratio of 1:1 to N,N-dimethylformamide (10 times the mass of heptamethylcyclotetrasiloxane), and 0.05 times the mass of heptamethylcyclotetrasiloxane was added with chloroplatinic acid, and the mixture was stirred at 80°C and 500 r / min for 2 h. The mixture was dried at 60°C under vacuum for 8 h to obtain flame retardant cyclotetrasiloxane. Tetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were uniformly mixed in a mass ratio of 1:1.3:0.03:0.03, stirred at 75°C and 500r / min for 20min, cooled to room temperature, washed with an equal volume of deionized water and toluene, allowed to stand for stratification, the aqueous phase was removed, and the washing was repeated 5 times. The organic phase was placed in a drying oven and dried at 60°C for 8h under vacuum conditions to obtain a siloxane oligomer. (3) Vanadium pentoxide and oxalic acid were added to deionized water (40 times the mass of vanadium pentoxide) in a molar ratio of 1:2, and then tungstic acid (0.6 times the mass of vanadium pentoxide) was added, and the mixture was stirred at 30°C and 500 r / min for 2 h. The mixture was placed in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 220°C for 60 h. The mixture was cooled to room temperature, filtered, washed with anhydrous ethanol and deionized water for 5 times each, dried at 80°C for 8 h under vacuum conditions, calcined at 800°C for 5 h under argon protection, cooled to room temperature, ground, and sieved through a 1200-mesh sieve to obtain tungsten-doped Mix allyl triethoxysilane and anhydrous ethanol at a mass ratio of 1:30, adjust the pH to 6 with a 1 mol / L oxalic acid aqueous solution, stir at 30°C and 500 r / min for 50 min to prepare a silane hydrolyzate; mix tungsten-doped vanadium dioxide and anhydrous ethanol at a mass ratio of 1:60, add silane hydrolyzate 10 times the mass of tungsten-doped vanadium dioxide, stir at 60°C and 500 r / min for 2 h, filter, wash with anhydrous ethanol 5 times, and dry at 60°C under vacuum conditions for 8 h to obtain modified vanadium dioxide; (4) 110 parts of castor oil, 200 parts of modified castor oil, 40 parts of siloxane oligomer, 210 parts of isophorone diisocyanate, 8 parts of cupric chloride, 3 parts of chloroplatinic acid and 120 parts of butanone were weighed and mixed evenly, stirred at 30°C and 500 r / min for 5 min, 5 parts of dibutyltin dilaurate were added, stirring was continued for 3 min, the mixture was poured into a polytetrafluoroethylene mold, kept at 80°C for 3 h and at 60°C for 6 h under vacuum conditions, cooled to room temperature and then demolded to obtain an adaptive dimming and temperature-controlling polyurethane protective film.

[0021] Comparative Example 1: The preparation method of the adaptive dimming temperature-control polyurethane protective film of Comparative Example 1 is different from that of Example 2 in that step (1) is not performed, and step (4) is modified as follows: 295 parts of castor oil, 35 parts of siloxane oligomer, 205 parts of isophorone diisocyanate, 7 parts of cupric chloride, 2.5 parts of chloroplatinic acid, and 110 parts of butanone are weighed and mixed uniformly, stirred at 20° C. and 400 r / min for 6 min, 4 parts of dibutyltin dilaurate are added, stirring is continued for 4 min, poured into a polytetrafluoroethylene mold, kept warm at 75° C. for 3.5 h and kept warm at 55° C. for 7 h under vacuum conditions, and demolded after cooling to room temperature to obtain an adaptive dimming temperature-control polyurethane protective film. The remaining steps are the same as those of Example 2.

[0022] Comparative Example 2: The preparation method of the adaptive dimming and temperature-controlling polyurethane protective film of Comparative Example 2 is different from that of Example 2 in step (2). Step (2) is modified as follows: heptamethylcyclotetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide are mixed uniformly in a mass ratio of 1:1.2:0.02:0.02, stirred at 70°C and 400r / min for 25min, cooled to room temperature, washed with an equal volume of deionized water and toluene, allowed to stand for stratification, the aqueous phase is removed, the washing is repeated 4 times, the organic phase is placed in a drying oven, and dried at 55°C for 9h under vacuum conditions to obtain a siloxane oligomer. The remaining steps are the same as those of Example 2.

[0023] Comparative Example 3: The preparation method of the adaptive dimming and temperature-controlling polyurethane protective film of Comparative Example 3 is different from that of Example 2 only in step (2). Step (2) is modified as follows: adding heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide in a molar ratio of 1:1 to N,N-dimethylformamide with a mass of 9 times that of heptamethylcyclotetrasiloxane, adding chloroplatinic acid with a mass of 0.04 times that of heptamethylcyclotetrasiloxane, stirring at 75°C and 400 r / min for 2.5 h, and vacuum drying for 3 hours. The flame retardant cyclotetrasiloxane was prepared by drying at 55°C for 9h under the following conditions: the flame retardant cyclotetrasiloxane, octamethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide were mixed uniformly in a mass ratio of 1:1.2:0.02:0.02, stirred at 70°C and 400r / min for 25min, cooled to room temperature, washed with an equal volume of deionized water and toluene, allowed to stand for stratification, the aqueous phase was removed, the washing was repeated 4 times, the organic phase was placed in a drying oven, dried at 55°C for 9h under vacuum conditions, and a siloxane oligomer was prepared. The remaining steps were the same as those in Example 2.

[0024] Comparative Example 4: The preparation method of the adaptive dimming and temperature-controlling polyurethane protective film of Comparative Example 4 is different from that of Example 2 only in step (3), and step (3) is modified as follows: allyl triethoxysilane and anhydrous ethanol are mixed evenly at a mass ratio of 1:25, the pH is adjusted to 5 with a 1 mol / L oxalic acid aqueous solution, and stirred at 20°C and 400 r / min for 55 min to prepare a silane hydrolyzate; vanadium dioxide and anhydrous ethanol are mixed evenly at a mass ratio of 1:55, silane hydrolyzate with a mass of 9 times that of vanadium dioxide is added, and the reaction is stirred at 55°C and 400 r / min for 2.5 h, filtered, washed with anhydrous ethanol 4 times, and dried at 55°C under vacuum for 9 h to prepare modified vanadium dioxide. The remaining steps are the same as those of Example 2.

[0025] Comparative Example 5: The preparation method of the adaptive dimming and temperature-controlling polyurethane protective film of Comparative Example 5 differs from that of Example 2 only in step (3). Step (3) is modified as follows: vanadium pentoxide and oxalic acid are added in a molar ratio of 1:2 to deionized water 35 times the mass of vanadium pentoxide, and then tungstic acid 0.55 times the mass of vanadium pentoxide is added, and the mixture is stirred at 20°C and 400 r / min for 2.5 h. The mixture is placed in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and hydrothermally reacted at 210°C for 65 h. The mixture is cooled to room temperature, filtered, washed with anhydrous ethanol and deionized water 4 times each, dried at 75°C under vacuum for 9 h, calcined at 750°C for 5.5 h under argon protection, cooled to room temperature, ground, and sieved through a 1100 mesh sieve to obtain modified vanadium dioxide.

[0026] Test Example 1 Test of adaptive dimming and temperature control performance Test method: The visible light transmittance of the embodiment and the comparative example at 10°C, 30°C and 80°C was tested using a variable temperature UV spectrometer produced by Shimadzu Corporation of Japan; the infrared blocking rate of the embodiment and the comparative example at 10°C, 30°C and 80°C was tested using a solar film tester produced by Shenzhen Linshang Technology Co., Ltd. The results are shown in Tables 1 and 2.

[0027] Table 1

[0028] Table 2

[0029] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 1 and Table 2, it can be found that the adaptive dimming and temperature-controlling polyurethane protective film prepared by the present invention has good adaptive dimming and temperature-controlling performance.

[0030] By comparison, the visible light transmittance of Examples 1 to 3 and Comparative Examples 1 to 5 does not change much at 10°C, 30°C and 80°C, indicating that the adaptive dimming and temperature-control polyurethane protective film has little effect on indoor lighting in high and low temperature seasons.

[0031] By comparison, the infrared blocking rates of Examples 1 to 3 and Comparative Example 4 at 10°C are not much different, but at 30°C, the infrared blocking rates of Examples 1 to 3 are much greater than that of Comparative Example 4. The infrared blocking rate of Comparative Example 4 at 30°C increases only slightly compared to that at 10°C, and increases significantly at 80°C, indicating that the phase transition of Examples 1 to 3 has occurred at ≤30°C, while the phase transition of Comparative Example 4 has occurred between 30 and 80°C, indicating that the phase transition temperature of Examples 1 to 3 is ≤30°C, while that of Comparative Example 4 is The phase transition temperature is higher than 30°C, indicating that tungsten-doped vanadium dioxide is prepared by reacting vanadium pentoxide, oxalic acid and tungstic acid; tungsten is doped into vanadium dioxide, and the doped tungsten atoms replace part of the vanadium atoms. The resulting defects introduce tensile stress into the vanadium dioxide lattice, thereby inducing lattice distortion. When the phase transition occurs, the d electron energy band of the outer layer of the vanadium atom overlaps at a lower temperature, which leads to a decrease in the phase transition temperature of vanadium dioxide; making the phase transition of vanadium dioxide occur at room temperature is more in line with people's needs for temperature regulation in the natural environment.

[0032] By comparison, the infrared blocking rate of Comparative Example 5 is higher than that of Examples 1 to 3 at 10°C, and is lower than that of Examples 1 to 3 at 30°C and 80°C, indicating that modified vanadium dioxide is prepared by reacting tungsten-doped vanadium dioxide and allyltriethoxysilane; a carbon-carbon double bond is introduced into the modified vanadium dioxide to improve the compatibility of tungsten-doped vanadium dioxide with the polyurethane resin, so that the tungsten-doped vanadium dioxide is uniformly dispersed in the polyurethane resin to avoid agglomeration, thereby giving full play to the intelligent temperature regulation effect of tungsten-doped vanadium dioxide.

[0033] Test Example 2 Flame retardant performance test Test method: The examples and comparative examples were prepared into standard specimens according to GB / T2406.2, and the limiting oxygen index of the standard specimens was tested. The results are shown in Table 3.

[0034] Table 3

[0035] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 3, it can be found that the adaptive dimming and temperature-controlling polyurethane protective film prepared by the present invention has good flame retardant properties.

[0036] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 2, indicating that the flame-retardant cyclotetrasiloxane is prepared by a hydrosilylation reaction between the Si-H bond on heptamethylcyclotetrasiloxane and the carbon-carbon double bond on 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide; the flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane are ring-opening polymerized to prepare a siloxane oligomer, and a DOPO structure is introduced into the molecular chain of the siloxane oligomer. The introduction of the DOPO structure can give the adaptive dimming and temperature-controlling polyurethane protective film excellent flame retardant properties.

[0037] Test Example 3 Mechanical properties testing Test method: The examples and comparative examples were prepared into standard specimens according to GB / T1040.3, and the tensile strength of the standard specimens was tested on an electronic universal testing machine. The results are shown in Table 4.

[0038] Table 4

[0039] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 5 in Table 4, it can be found that the adaptive dimming and temperature-controlling polyurethane protective film prepared by the present invention has good mechanical properties.

[0040] By comparison, the tensile strength of Examples 1 to 3 is greater than that of Comparative Example 1, indicating that the amino group on 4-benzyl-3-thiosemicarbazide and the aldehyde group on mercaptoacetaldehyde undergo Schiff base reaction to obtain thiolated thiosemicarbazide, and a thiol group is introduced into the thiolated thiosemicarbazide; the carbon-carbon double bond on castor oil and the thiol group on the thiolated thiosemicarbazide undergo addition reaction to obtain modified castor oil, and a thiosemicarbazide structure is introduced into the modified castor oil molecular chain, and the thiosemicarbazide structure can react with copper chloride to form a copper complex, and the copper ions form coordination bonds with the thiosemicarbazide structure, thereby increasing the cross-linking sites of the system, inhibiting the relative slip of the molecular chain, and giving the adaptive dimming and temperature-controlling polyurethane protective film excellent mechanical properties.

[0041] By comparison, the tensile strength of Examples 1 to 3 is greater than that of Comparative Example 3, indicating that the flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane are ring-opening polymerized to prepare the siloxane oligomer, and Si-H bonds are introduced into the siloxane oligomer molecular chain. The Si-H bonds introduced into the siloxane oligomer molecular chain can react with the carbon-carbon double bonds on castor oil and modified vanadium dioxide to form a cross-linked network, thereby inhibiting the relative slip between the molecular chains and improving the excellent mechanical properties of the adaptive dimming and temperature-controlling polyurethane protective film.

[0042] By comparison, the tensile strength of Examples 1 to 3 is greater than that of Comparative Example 5, indicating that modified vanadium dioxide is prepared by reacting tungsten-doped vanadium dioxide and allyltriethoxysilane; a carbon-carbon double bond is introduced into the modified vanadium dioxide, and the carbon-carbon double bond introduced into the modified vanadium dioxide can also undergo an addition reaction with the Si-H bond on the siloxane oligomer to form a cross-linked network, thereby further improving the mechanical properties of the adaptive dimming and temperature-controlling polyurethane protective film.

[0043] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An adaptive dimming and temperature-controlling polyurethane protective film, characterized in that: The adaptive dimming and temperature-controlling polyurethane protective film is prepared by reacting castor oil with thiosulfated thiosemicarbazone to obtain modified castor oil; ring-opening polymerization of flame-retardant cyclotetrasiloxane and tetramethylcyclotetrasiloxane to obtain siloxane oligomers; reacting tungsten-doped vanadium dioxide and allyl triethoxysilane to obtain modified vanadium dioxide; and uniformly mixing castor oil, modified castor oil, siloxane oligomers, isophorone diisocyanate and cupric chloride, pouring the mixture into a mold and curing and forming the mixture to obtain the adaptive dimming and temperature-controlling polyurethane protective film. The thiolated thiosemicarbazone is prepared by reacting 4-benzyl-3-thiosemicarbazone and mercaptoacetaldehyde; The flame retardant cyclotetrasiloxane is prepared by reacting heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide; The tungsten-doped vanadium dioxide is prepared by hydrothermal reaction with vanadium pentoxide as a raw material, oxalic acid as a reducing agent, and tungstic acid as a doping agent.

2. A method for preparing an adaptive dimming and temperature-controlling polyurethane protective film, characterized in that: The preparation method of the adaptive dimming and temperature-controlling polyurethane protective film comprises the following preparation steps: (1) Castor oil, thiosulfated thiosemicarbazone, azobisisobutyronitrile and toluene are mixed uniformly in a mass ratio of 1:(0.5-0.6):(0.03-0.05):(8-10), stirred at 70-80°C and 300-500 r / min for 3-4 h, and dried at 50-60°C under vacuum for 8-10 h to obtain modified castor oil; (2) Mix flame retardant cyclotetrasiloxane, tetramethylcyclotetrasiloxane, tetramethylammonium hydroxide and dimethyl sulfoxide in a mass ratio of 1:(1.1-1.3):(0.01-0.03):(0.01-0.03), stir and react at 65-75°C and 300-500r / min for 20-30min, cool to room temperature, wash with an equal volume of deionized water and toluene, let stand to separate, remove the aqueous phase, repeat washing 3-5 times, take the organic phase and place it in a drying oven, dry it at 50-60°C under vacuum conditions for 8-10h to obtain a siloxane oligomer; (3) Add vanadium pentoxide and oxalic acid in a molar ratio of 1:2 to deionized water with a mass of 30 to 40 times the mass of vanadium pentoxide, then add tungstic acid with a mass of 0.5 to 0.6 times the mass of vanadium pentoxide, stir and react at 10 to 30°C and 300 to 500 r / min for 2 to 3 hours, place in a stainless steel hydrothermal reactor lined with polytetrafluoroethylene, hydrothermally react at 200 to 220°C for 60 to 70 hours, cool to room temperature, filter, wash with anhydrous ethanol and deionized water 3 to 5 times each, and under vacuum conditions, Dry at 70-80°C for 8-10 hours, calcine at high temperature, cool to room temperature, grind, and sieve to obtain tungsten-doped vanadium dioxide; mix tungsten-doped vanadium dioxide and anhydrous ethanol at a mass ratio of 1:(50-60) evenly, add silane hydrolyzate of 8-10 times the mass of tungsten-doped vanadium dioxide, stir at 50-60°C, 300-500r / min for 2-3 hours, filter, wash with anhydrous ethanol 3-5 times, and dry at 50-60°C for 8-10 hours under vacuum conditions to obtain modified vanadium dioxide; (4) Weigh 100-110 parts of castor oil, 180-200 parts of modified castor oil, 30-40 parts of siloxane oligomer, 200-210 parts of isophorone diisocyanate, 6-8 parts of cupric chloride, 2-3 parts of chloroplatinic acid, and 100-120 parts of butanone, mix them evenly, stir at 10-30°C and 300-500 r / min for 5-7 min, add 3-5 parts of dibutyltin dilaurate, continue stirring for 3-5 min, pour into a polytetrafluoroethylene mold, keep warm at 70-80°C for 3-4 h and at 50-60°C for 6-8 h under vacuum conditions, cool to room temperature and then demould to obtain an adaptive dimming and temperature-control polyurethane protective film.

3. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The preparation method of the thiolated thiosemicarbazone in step (1) is as follows: 4-benzyl-3-thiosemicarbazone and mercaptoacetaldehyde are added in a molar ratio of 1:1 to methanol with a mass that is 10 to 12 times that of 4-benzyl-3-thiosemicarbazone, and the mixture is stirred at 50 to 60° C. and 300 to 500 r / min for 20 to 24 hours, and dried at 50 to 60° C. under vacuum conditions for 8 to 10 hours to obtain the thiolated thiosemicarbazone.

4. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The hydroxyl value of the castor oil in step (1) is 164 mg KOH / g.

5. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The preparation method of the flame retardant cyclotetrasiloxane in step (2) is as follows: adding heptamethylcyclotetrasiloxane and 9,10-dihydro-9-oxa-10-allylphosphaphenanthrene-10-oxide in a molar ratio of 1:1 to N,N-dimethylformamide with a mass of 8 to 10 times that of heptamethylcyclotetrasiloxane, adding chloroplatinic acid with a mass of 0.03 to 0.05 times that of heptamethylcyclotetrasiloxane, stirring and reacting at 70 to 80° C. and 300 to 500 r / min for 2 to 3 hours, and drying at 50 to 60° C. under vacuum conditions for 8 to 10 hours to obtain the flame retardant cyclotetrasiloxane.

6. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The conditions for high temperature calcination in step (3) are: calcination at 700-800° C. for 5-6 hours under argon protection.

7. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The sieving in step (3) is performed through a 1000-1200 mesh sieve.

8. The method for preparing the adaptive dimming and temperature-controlling polyurethane protective film according to claim 2, characterized in that: The preparation method of the silane hydrolyzate in step (3) is as follows: allyl triethoxysilane and anhydrous ethanol are uniformly mixed in a mass ratio of 1:(20-30), the pH is adjusted to 4-6 with a 1 mol / L oxalic acid aqueous solution, and the mixture is stirred at 10-30° C. and 300-500 r / min for 50-60 min to prepare a silane hydrolyzate.

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