Far infrared thermal polyurethane transfer film containing graphene and preparation method

Abstract

The present application relates to the technical field of transfer film, in particular to a far-infrared thermal polyurethane transfer film containing graphene and a preparation method.The far-infrared thermal polyurethane transfer film containing graphene comprises a support layer, a polyurethane transfer layer and an adhesive layer, the polyurethane transfer layer is located on one side of the support layer, and the adhesive layer is located on the other side of the polyurethane transfer layer; the polyurethane transfer layer is prepared from polyurethane resin, an organic solvent, an organic pigment and a composite modifier, wherein the composite modifier is prepared from alkenyl modified graphene oxide, chloropropylene modified hindered phenol and 4-propyleneoxy-2-hydroxybenzophenone, and the addition of the composite modifier enables the polyurethane transfer film to have far-infrared thermal properties and good oxidation resistance and hydrolysis resistance.

Description

Technical Field

[0001] This invention relates to the field of transfer film technology, specifically to a far-infrared heat-insulating polyurethane transfer film containing graphene and its preparation method. Background Technology

[0002] While genuine leather offers advantages such as breathability, softness, and warmth, it suffers from high raw material costs and an expensive price. Polyurethane synthetic leather, a type of imitation leather material, closely resembles the texture of genuine leather and has largely replaced it, especially microfiber leather, which is now widely used. Microfiber leather is made by combining a leather base fabric made of polyester or nylon microfibers with polyurethane, resulting in a soft, delicate feel and high abrasion resistance. Currently, the production processes for polyurethane synthetic leather mainly include wet-dry and fully dry processes. However, the wet-dry process is longer, while the fully dry process involves coating resin onto release paper, directly laminating it, and then drying to form the finished product, resulting in a shorter process.

[0003] Polyurethane resins include polyether-type polyurethane and polyester-type polyurethane. Polyether-type polyurethane has good wear resistance and flexibility, while polyester-type polyurethane has good mechanical strength. By using the two resins in combination, the overall performance of the material can be improved. For example, Chinese patent CN 101204867B discloses a method for manufacturing a PU transfer film. Using plain weave Oxford cloth as a carrier, a wet-process polyurethane coating is first coated on the plain weave Oxford cloth. Then, a dry-process PU transfer coating with a leather texture is laminated on the wet-process polyurethane coating. Finally, the plain weave Oxford cloth is peeled off to obtain the PU transfer film. The wet-process slurry formulation includes polyurethane resin, DMF, solvent-based pigments, and wood powder. The dry-process slurry formulation includes polyurethane resin, solvent, pigments, and leveling agent. The polyurethane resin includes polyester-type polyurethane resin and polyether-type polyurethane resin. However, polyurethane materials are prone to oxidation and cracking when exposed to air for a long time, and organic pigments are prone to fading under ultraviolet radiation. In addition, for polyester-type polyurethane, it is necessary to improve its hydrolysis resistance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a far-infrared heat-insulating polyurethane transfer film containing graphene and its preparation method, thereby solving the problem that the antioxidant and hydrolysis resistance properties of polyurethane-based materials in existing technologies need to be improved.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A far-infrared warming polyurethane transfer film containing graphene includes a support layer, a polyurethane transfer layer and an adhesive layer, wherein the polyurethane transfer layer is located on one side of the support layer and the adhesive layer is located on the other side of the polyurethane transfer layer.

[0007] The support layer includes a PET release film layer;

[0008] The adhesive layer includes a hot melt adhesive film layer;

[0009] The raw materials for preparing the polyurethane transfer layer include: polyurethane resin, organic solvent, organic pigment, and composite modifier;

[0010] The composite modifier is prepared by the following steps:

[0011] S1. Preparation of alkenyl-modified graphene oxide and chloropropenyl-modified hindered phenol;

[0012] The preparation of alkenyl-modified graphene oxide includes:

[0013] Carboxylated graphene oxide was reacted with γ-methacryloyloxypropyltrimethoxysilane to prepare alkenyl-modified graphene oxide.

[0014] The preparation of chloropropenyl-modified hindered phenols includes:

[0015] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine was reacted with 2-chloropropenyl isothiocyanate to prepare chloropropenyl-modified hindered phenol.

[0016] A composite modifier is prepared by reacting S2, alkenyl-modified graphene oxide, chloropropenyl-modified hindered phenol, and 4-propenoxy-2-hydroxybenzophenone.

[0017] Preferably, the mass ratio of the polyurethane resin, organic solvent, organic pigment, and composite modifier is 100:(35-45):(2-3):(4-8);

[0018] The polyurethane resin includes polyether-type polyurethane resin and polyester-type polyurethane resin;

[0019] The mass ratio of the polyether-type polyurethane resin to the polyester-type polyurethane resin is (0.5-2):1;

[0020] The organic solvent includes N,N-dimethylformamide (DMF).

[0021] Preferably, in step S1, the preparation of alkenyl-modified graphene oxide specifically includes:

[0022] Carboxylated graphene oxide was added to ethanol, ultrasonically dispersed, and the pH was adjusted to 5-6. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. After the addition was complete, the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain alkenyl-modified graphene oxide.

[0023] The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture is 1:(50-60):(80-120), and the reaction conditions are 50-70℃ for 20-30h.

[0024] Preferably, the γ-methacryloxypropyltrimethoxysilane-ethanol mixture is prepared by γ-methacryloxypropyltrimethoxysilane (KH-570) and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane is 25-35g / L.

[0025] Preferably, the carboxylated graphene oxide is prepared by the following steps:

[0026] Graphene oxide was dispersed in deionized water and ultrasonically dispersed to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion and reacted. After the reaction was completed, the mixture was filtered, washed, and dried to obtain carboxylated graphene oxide.

[0027] The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid is 0.1:(80-120):(5.5-6.5):(4.5-5.5), and the reaction conditions are ultrasonic reaction at a frequency of 60-80kHz for 2.5-3.5h.

[0028] Preferably, in step S1, the preparation of the chloropropenyl-modified hindered phenol specifically includes:

[0029] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine and 2-chloropropenyl isothiocyanate were added to ethanol and reacted. After the reaction was completed, the mixture was cooled, filtered, and recrystallized to obtain thiourea-modified hindered phenol.

[0030] The mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine, 2-chloropropenyl isothiocyanate, and ethanol is 29.2:(14-16):(400-600), and the reaction conditions are reflux reaction at 85-95℃ for 4-5h.

[0031] Thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water were mixed and reacted. After the reaction was completed, the mixture was separated, purified, and dried to obtain chloropropenyl-modified hindered phenol.

[0032] The mass ratio of thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water is 4.3:(8.2-8.5):(205-220):(135-145), and the reaction conditions are stirring at room temperature for 45-50 hours.

[0033] Preferably, in step S2, the preparation of the composite modifier specifically includes:

[0034] 4-Acryloxy-2-hydroxybenzophenone was added to toluene and stirred until dissolved to obtain a 4-acryloxy-2-hydroxybenzophenone solution. Benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol were added to the 4-acryloxy-2-hydroxybenzophenone solution, stirred and dispersed, and then heated to a set temperature for reaction. After the reaction was completed, the mixture was rotary evaporated, purified, and dried to obtain the composite modifier.

[0035] The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol is (50.8-55):(800-1000):(1.8-4.2):(48-52):(42.6-44), and the reaction conditions are to react at a set temperature for 1-2 hours.

[0036] The set temperature is 90-100℃.

[0037] This invention also discloses a method for preparing a graphene-containing far-infrared heat-insulating polyurethane transfer film as described above, comprising the following steps:

[0038] Step (1): Dissolve polyurethane resin in an organic solvent, add organic pigments and composite modifiers, stir and mix to obtain a slurry; coat the slurry onto the surface of the support layer, and after solidification, water washing and drying, form a polyurethane transfer layer;

[0039] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0040] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0041] Preferably, in step (1), the coating amount of the slurry is 180-240 g / m². 2 The solidification conditions are as follows: solidify in 16wt%-20wt% N,N-dimethylformamide aqueous solution at room temperature for 15-20 min; water washing conditions are as follows: water washing at 60-80℃, extrusion every 5 min during water washing, for 5-10 times; drying conditions are as follows: drying at 100-120℃ for 10-20 min.

[0042] Preferably, in step (2), the thickness of the hot melt adhesive film is 0.1-0.2 mm, the softening point of the hot melt adhesive film is 120-130℃, and the pressing pressure is 4-6 MPa.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] In this invention, polyether-type polyurethane and polyester-type polyurethane are used in combination, which can combine the excellent wear resistance and flexibility of polyether-type polyurethane with the high mechanical strength of polyester-type polyurethane, resulting in a polyurethane transfer film with good overall performance.

[0045] This invention introduces a composite modifier based on graphene oxide, hindered phenolic antioxidants, and ultraviolet absorbers, which effectively improves the far-infrared heat retention, antioxidant aging resistance, and UV resistance of polyurethane transfer films. In the preparation of the composite modifier, graphene oxide reacts with the silane coupling agent γ-methacryloyloxypropyltrimethoxysilane to obtain alkenyl-modified graphene oxide. The hindered phenolic antioxidant 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine reacts with 2-chloropropene... The reaction of isothiocyanate yields chloropropenyl-modified hindered phenol, alkenyl-modified graphene oxide, chloropropenyl-modified hindered phenol, and 4-propenoxy-2-hydroxybenzophenone. Through the reaction of alkenyl groups contained in their respective molecular structures under the action of an initiator, polymers are formed, realizing chemical bonding between the functional components. This improves the compatibility and dispersion uniformity of the functional components with the matrix resin as the polymer molecular chains intertwine with the polyurethane molecular chains. At the same time, it can also prevent the migration of small molecule functional components.

[0046] In the process of modifying the hindered phenolic antioxidant 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine to introduce alkenyl groups, the hydrazine group reacts and bonds with the isothiocyanate group to generate a carbodiimide group, which has excellent hydrolysis resistance and can effectively improve the hydrolysis resistance of polyester polyurethane. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of the far-infrared heat-insulating polyurethane transfer film containing graphene prepared in this invention.

[0048] In the diagram: 1. Support layer; 2. Polyurethane transfer layer; 3. Adhesive layer. Detailed Implementation

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] Example 1

[0051] This embodiment discloses a method for preparing a far-infrared heat-insulating polyurethane transfer film containing graphene, comprising the following steps:

[0052] Step (1): Dissolve polyether-type polyurethane resin and polyester-type polyurethane resin in N,N-dimethylformamide, add organic pigment Permanent Yellow GG and composite modifier, stir and mix to obtain slurry;

[0053] The mass ratio of polyether polyurethane resin, polyester polyurethane resin, N,N-dimethylformamide, organic pigment Permanent Yellow GG and composite modifier is 50:50:35:2:4.

[0054] The composite modifier is prepared by the following steps:

[0055] S1. Preparation of alkenyl-modified graphene oxide and chloropropenyl-modified hindered phenol;

[0056] The preparation of alkenyl-modified graphene oxide includes:

[0057] Graphene oxide was dispersed in deionized water and ultrasonically dispersed at 50 kHz for 30 min to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid was 0.1:80:5.5:4.5. The mixture was ultrasonically reacted at 60 kHz for 3.5 h. After the reaction was completed, the mixture was filtered, washed three times with deionized water, and dried in a vacuum drying oven at 50 ℃ for 24 h to obtain carboxylated graphene oxide.

[0058] Carboxylated graphene oxide was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. The pH was adjusted to 5 with 1 mol / L hydrochloric acid. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture was 1:50:80. After the addition was complete, the mixture was reacted at 50 °C for 30 h. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified graphene oxide.

[0059] The γ-methacryloxypropyltrimethoxysilane-ethanol mixture was prepared by γ-methacryloxypropyltrimethoxysilane and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane was 35g / L.

[0060] The preparation of chloropropenyl-modified hindered phenols includes:

[0061] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazide and 2-chloropropenyl isothiocyanate were added to ethanol in a mass ratio of 29.2:14:400. The mixture was refluxed at 85°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and recrystallized with a mixed solvent of chloroform and petroleum ether to obtain thiourea-modified hindered phenol.

[0062] Thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water were mixed in a mass ratio of 4.3:8.2:205:135. The mixture was stirred at room temperature for 45 hours. After the reaction was completed, the chloroform layer turned black. The mixture was filtered until the filtrate became clear. After drying with CaCl2 for 2 hours, the mixture was filtered again. The solvent was removed from the filtrate under reduced pressure, and the filtrate was recrystallized with ethyl acetate. The recrystallized filtrate was dried in a vacuum drying oven at 50°C for 12 hours to obtain chloropropenyl-modified hindered phenol.

[0063] S2. Add 4-propenoxy-2-hydroxybenzophenone to toluene and stir until dissolved to obtain a 4-propenoxy-2-hydroxybenzophenone solution. Add benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol to the 4-propenoxy-2-hydroxybenzophenone solution. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol is 50.8:800:1.8:48:42.6. After stirring and dispersing, heat to 90℃ and react at 90℃ for 2 hours. After the reaction is completed, remove toluene by rotary evaporation at 75℃. Wash the product after rotary evaporation three times with ethanol and dry it in a vacuum drying oven at 50℃ for 12 hours to obtain the composite modifier.

[0064] The slurry is coated onto the surface of a PET release film, and after coagulation, washing, and drying, a polyurethane transfer layer is formed.

[0065] The coating amount of the slurry is 200g / m². 2 The solidification conditions were as follows: solidification in 18wt% N,N-dimethylformamide aqueous solution at room temperature for 20 min; water washing conditions were as follows: water washing at 70℃, with extrusion every 5 min for 10 times; and drying conditions were as follows: drying at 110℃ for 15 min.

[0066] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0067] The thickness of the hot melt adhesive film is 0.15 mm, the softening point of the hot melt adhesive film is 126℃, and the pressing pressure is 5 MPa.

[0068] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0069] Example 2

[0070] This embodiment discloses a method for preparing a far-infrared heat-insulating polyurethane transfer film containing graphene, comprising the following steps:

[0071] Step (1): Dissolve polyether-type polyurethane resin and polyester-type polyurethane resin in N,N-dimethylformamide, add organic pigment Permanent Yellow GG and composite modifier, stir and mix to obtain slurry;

[0072] The mass ratio of polyether polyurethane resin, polyester polyurethane resin, N,N-dimethylformamide, organic pigment Permanent Yellow GG and composite modifier is 50:50:3:8.

[0073] The composite modifier is prepared by the following steps:

[0074] S1. Preparation of alkenyl-modified graphene oxide and chloropropenyl-modified hindered phenol;

[0075] The preparation of alkenyl-modified graphene oxide includes:

[0076] Graphene oxide was dispersed in deionized water and ultrasonically dispersed at 50 kHz for 30 min to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid was 0.1:120:6.5:5.5. The mixture was ultrasonically reacted at 80 kHz for 2.5 h. After the reaction was completed, the mixture was filtered, washed three times with deionized water, and dried in a vacuum drying oven at 50 ℃ for 24 h to obtain carboxylated graphene oxide.

[0077] Carboxylated graphene oxide was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. The pH was adjusted to 6 with 1 mol / L hydrochloric acid. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture was 1:60:120. After the addition was complete, the mixture was reacted at 70 °C for 20 h. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified graphene oxide.

[0078] The γ-methacryloxypropyltrimethoxysilane-ethanol mixture was prepared by γ-methacryloxypropyltrimethoxysilane and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane was 25g / L.

[0079] The preparation of chloropropenyl-modified hindered phenols includes:

[0080] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazide and 2-chloropropenyl isothiocyanate were added to ethanol in a mass ratio of 29.2:16:600. The mixture was refluxed at 95°C for 4 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and recrystallized with a mixed solvent of chloroform and petroleum ether to obtain thiourea-modified hindered phenol.

[0081] Thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water were mixed in a mass ratio of 4.3:8.5:220:145. The mixture was stirred at room temperature for 50 hours. After the reaction was completed, the chloroform layer turned black. The mixture was filtered until the filtrate became clear. After drying with CaCl2 for 2 hours, the mixture was filtered again. The solvent was removed from the filtrate under reduced pressure, and the filtrate was recrystallized with ethyl acetate. The recrystallized filtrate was dried in a vacuum drying oven at 50°C for 12 hours to obtain chloropropenyl-modified hindered phenol.

[0082] S2. Add 4-propenoxy-2-hydroxybenzophenone to toluene and stir until dissolved to obtain a 4-propenoxy-2-hydroxybenzophenone solution. Add benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol to the 4-propenoxy-2-hydroxybenzophenone solution. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol is 55:1000:4.2:52:44. After stirring and dispersing, heat to 100℃ and react at 100℃ for 1 hour. After the reaction is completed, remove toluene by rotary evaporation at 75℃. Wash the product after rotary evaporation three times with ethanol and dry it in a vacuum drying oven at 50℃ for 12 hours to obtain the composite modifier.

[0083] The slurry is coated onto the surface of a PET release film, and after coagulation, washing, and drying, a polyurethane transfer layer is formed.

[0084] The coating amount of the slurry is 200g / m². 2The solidification conditions were as follows: solidification in 18wt% N,N-dimethylformamide aqueous solution at room temperature for 20 min; water washing conditions were as follows: water washing at 70℃, with extrusion every 5 min for 10 times; drying conditions were as follows: drying at 110℃ for 15 min.

[0085] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0086] The thickness of the hot melt adhesive film is 0.15 mm, the softening point of the hot melt adhesive film is 126℃, and the pressing pressure is 5 MPa.

[0087] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0088] Example 3

[0089] This embodiment discloses a method for preparing a far-infrared heat-insulating polyurethane transfer film containing graphene, comprising the following steps:

[0090] Step (1): Dissolve polyether-type polyurethane resin and polyester-type polyurethane resin in N,N-dimethylformamide, add organic pigment Permanent Yellow GG and composite modifier, stir and mix to obtain slurry;

[0091] The mass ratio of polyether polyurethane resin, polyester polyurethane resin, N,N-dimethylformamide, organic pigment Permanent Yellow GG, and composite modifier is 50:50:40:2.5:6.

[0092] The composite modifier is prepared by the following steps:

[0093] S1. Preparation of alkenyl-modified graphene oxide and chloropropenyl-modified hindered phenol;

[0094] The preparation of alkenyl-modified graphene oxide includes:

[0095] Graphene oxide was dispersed in deionized water and ultrasonically dispersed at 50 kHz for 30 min to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid was 0.1:100:6:5. The mixture was ultrasonically reacted at 70 kHz for 3 h. After the reaction was completed, the mixture was filtered, washed three times with deionized water, and dried in a vacuum drying oven at 50 ℃ for 24 h to obtain carboxylated graphene oxide.

[0096] Carboxylated graphene oxide was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. The pH was adjusted to 5.5 with 1 mol / L hydrochloric acid. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture was 1:55:100. After the addition was complete, the mixture was reacted at 60 °C for 24 h. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified graphene oxide.

[0097] The γ-methacryloxypropyltrimethoxysilane-ethanol mixture was prepared by γ-methacryloxypropyltrimethoxysilane and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane was 30g / L.

[0098] The preparation of chloropropenyl-modified hindered phenols includes:

[0099] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazide and 2-chloropropenyl isothiocyanate were added to ethanol in a mass ratio of 29.2:15:500. The mixture was refluxed at 90°C for 4.5 h. After the reaction was completed, the mixture was cooled to room temperature, filtered, and recrystallized from a mixed solvent of chloroform and petroleum ether to obtain thiourea-modified hindered phenol.

[0100] Thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water were mixed in a mass ratio of 4.3:8.4:215:140. The mixture was stirred at room temperature for 48 hours. After the reaction was completed, the chloroform layer turned black. The mixture was filtered until the filtrate became clear. After drying with CaCl2 for 2 hours, the mixture was filtered again. The solvent was removed from the filtrate under reduced pressure, and the filtrate was recrystallized with ethyl acetate. The recrystallized filtrate was dried in a vacuum drying oven at 50°C for 12 hours to obtain chloropropenyl-modified hindered phenol.

[0101] S2. Add 4-propenoxy-2-hydroxybenzophenone to toluene and stir until dissolved to obtain a 4-propenoxy-2-hydroxybenzophenone solution. Add benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol to the 4-propenoxy-2-hydroxybenzophenone solution. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol is 53:900:3.6:50:43.5. After stirring and dispersing, heat to 95℃ and react at 95℃ for 1.5 h. After the reaction is completed, remove toluene by rotary evaporation at 75℃. Wash the product after rotary evaporation three times with ethanol and dry it in a vacuum drying oven at 50℃ for 12 h to obtain the composite modifier.

[0102] The slurry is coated onto the surface of a PET release film, and after coagulation, washing, and drying, a polyurethane transfer layer is formed.

[0103] The coating amount of the slurry is 200g / m². 2 The solidification conditions were as follows: solidification in 18wt% N,N-dimethylformamide aqueous solution at room temperature for 20 min; water washing conditions were as follows: water washing at 70℃, with extrusion every 5 min for 10 times; and drying conditions were as follows: drying at 110℃ for 15 min.

[0104] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0105] The thickness of the hot melt adhesive film is 0.15 mm, the softening point of the hot melt adhesive film is 126℃, and the pressing pressure is 5 MPa.

[0106] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0107] Comparative Example 1

[0108] This comparative example discloses a method for preparing a far-infrared heat-insulating polyurethane transfer film containing graphene, comprising the following steps:

[0109] Step (1): Dissolve polyether-type polyurethane resin and polyester-type polyurethane resin in N,N-dimethylformamide, add organic pigment Permanent Yellow GG and composite modifier, stir and mix to obtain slurry;

[0110] The mass ratio of polyether polyurethane resin, polyester polyurethane resin, N,N-dimethylformamide, organic pigment Permanent Yellow GG and composite modifier is 50:50:35:2:4.

[0111] The composite modifier is prepared by the following steps:

[0112] S1. Preparation of alkenyl-modified graphene oxide:

[0113] Graphene oxide was dispersed in deionized water and ultrasonically dispersed at 50 kHz for 30 min to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid was 0.1:80:5.5:4.5. The mixture was ultrasonically reacted at 60 kHz for 3.5 h. After the reaction was completed, the mixture was filtered, washed three times with deionized water, and dried in a vacuum drying oven at 50 ℃ for 24 h to obtain carboxylated graphene oxide.

[0114] Carboxylated graphene oxide was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. The pH was adjusted to 5 with 1 mol / L hydrochloric acid. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture was 1:50:80. After the addition was complete, the mixture was reacted at 50 °C for 30 h. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified graphene oxide.

[0115] The γ-methacryloxypropyltrimethoxysilane-ethanol mixture was prepared by γ-methacryloxypropyltrimethoxysilane and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane was 35g / L.

[0116] S2. Add 4-propenoxy-2-hydroxybenzophenone to toluene and stir until dissolved to obtain a 4-propenoxy-2-hydroxybenzophenone solution. Add benzoyl peroxide and alkenyl-modified graphene oxide to the 4-propenoxy-2-hydroxybenzophenone solution. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, and alkenyl-modified graphene oxide is 50.8:800:1.8:48. After stirring and dispersing, heat to 90℃ and react at 90℃ for 2 hours. After the reaction is completed, remove toluene by rotary evaporation at 75℃. Wash the product after rotary evaporation three times with ethanol and dry it in a vacuum drying oven at 50℃ for 12 hours to obtain the composite modifier.

[0117] The slurry is coated onto the surface of a PET release film, and after coagulation, washing, and drying, a polyurethane transfer layer is formed.

[0118] The coating amount of the slurry is 200g / m². 2The solidification conditions were as follows: solidification in 18wt% N,N-dimethylformamide aqueous solution at room temperature for 20 min; water washing conditions were as follows: water washing at 70℃, with extrusion every 5 min for 10 times; and drying conditions were as follows: drying at 110℃ for 15 min.

[0119] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0120] The thickness of the hot melt adhesive film is 0.15 mm, the softening point of the hot melt adhesive film is 126℃, and the pressing pressure is 5 MPa.

[0121] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0122] Comparative Example 2

[0123] This comparative example discloses a method for preparing a far-infrared heat-insulating polyurethane transfer film containing graphene, comprising the following steps:

[0124] Step (1): Dissolve polyether-type polyurethane resin and polyester-type polyurethane resin in N,N-dimethylformamide, add organic pigment Permanent Yellow GG and composite modifier, stir and mix to obtain slurry;

[0125] The mass ratio of polyether polyurethane resin, polyester polyurethane resin, N,N-dimethylformamide, organic pigment Permanent Yellow GG and composite modifier is 50:50:35:2:4.

[0126] The composite modifier is prepared by the following steps:

[0127] S1. Preparation of alkenyl-modified graphene oxide and alkenyl-modified hindered phenol;

[0128] The preparation of alkenyl-modified graphene oxide includes:

[0129] Graphene oxide was dispersed in deionized water and ultrasonically dispersed at 50 kHz for 30 min to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid was 0.1:80:5.5:4.5. The mixture was ultrasonically reacted at 60 kHz for 3.5 h. After the reaction was completed, the mixture was filtered, washed three times with deionized water, and dried in a vacuum drying oven at 50 ℃ for 24 h to obtain carboxylated graphene oxide.

[0130] Carboxylated graphene oxide was added to ethanol and ultrasonically dispersed at 50 kHz for 30 min. The pH was adjusted to 5 with 1 mol / L hydrochloric acid. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture was 1:50:80. After the addition was complete, the mixture was reacted at 50 °C for 30 h. After the reaction was completed, the mixture was filtered, washed three times with ethanol, and dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified graphene oxide.

[0131] The γ-methacryloxypropyltrimethoxysilane-ethanol mixture was prepared by γ-methacryloxypropyltrimethoxysilane and 95wt% aqueous ethanol solution, and the concentration of γ-methacryloxypropyltrimethoxysilane was 35g / L.

[0132] The preparation of alkenyl-modified hindered phenols includes:

[0133] 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine was added to toluene, and 3-propene isocyanate was added dropwise with stirring in an ice bath. The mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine, toluene, and 3-propene isocyanate was 29.2:500:9. The dropwise addition of 3-propene isocyanate takes 30 min. After the addition is complete, the reaction is carried out at 5 °C for 5 h. After the reaction is complete, the mixture is filtered, and the filter cake is recrystallized with chloroform. The recrystallized mixture is dried in a vacuum drying oven at 50 °C for 12 h to obtain alkenyl-modified hindered phenol.

[0134] S2. Add 4-propenoxy-2-hydroxybenzophenone to toluene and stir until dissolved to obtain a 4-propenoxy-2-hydroxybenzophenone solution. Add benzoyl peroxide, alkenyl-modified graphene oxide, and alkenyl-modified hindered phenol to the 4-propenoxy-2-hydroxybenzophenone solution. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and alkenyl-modified hindered phenol is 50.8:800:1.8:48:42.6. After stirring and dispersing, heat to 90℃ and react at 90℃ for 2 hours. After the reaction is completed, remove toluene by rotary evaporation at 75℃. Wash the product after rotary evaporation three times with ethanol and dry it in a vacuum drying oven at 50℃ for 12 hours to obtain the composite modifier.

[0135] The slurry is coated onto the surface of a PET release film, and after coagulation, washing, and drying, a polyurethane transfer layer is formed.

[0136] The coating amount of the slurry is 200g / m². 2The solidification conditions were as follows: solidification in 18wt% N,N-dimethylformamide aqueous solution at room temperature for 20 min; water washing conditions were as follows: water washing at 70℃, with extrusion every 5 min for 10 times; and drying conditions were as follows: drying at 110℃ for 15 min.

[0137] Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene.

[0138] The thickness of the hot melt adhesive film is 0.15 mm, the softening point of the hot melt adhesive film is 126℃, and the pressing pressure is 5 MPa.

[0139] The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

[0140] In the above embodiments and comparative examples, the polyester-type polyurethane is polycarbonate polyurethane with a processing temperature of 160-180℃, and the polyether-type polyurethane is polytetrahydrofuran ether diol polyurethane with a temperature resistance of 120-130℃.

[0141] Test case

[0142] (1) Thermal insulation performance and far-infrared heating performance: The polyurethane transfer film was bonded to the surface of the leather base fabric, with the adhesive layer of the polyurethane transfer film in contact with the leather base fabric. After pressing and cooling, a polyurethane synthetic leather sample was obtained. The thermal insulation performance of the synthetic leather sample was determined according to the standard GB / T35762-2017 "Test Method for Heat Transfer Properties of Textiles - Flat Plate Method". The far-infrared heating performance of the synthetic leather sample was determined according to the standard GB / T30127-2013 "Detection and Evaluation of Far-infrared Properties of Textiles". The test results of thermal insulation performance and far-infrared heating performance are shown in Table 1 and Table 2, respectively.

[0143] Table 1

[0144]

[0145] As shown in Table 1, the polyurethane transfer film prepared by this invention has good thermal insulation properties. The introduction of graphene can effectively improve the thermal insulation properties of the polyurethane transfer film; the higher the clo value, the better the thermal insulation properties of the polyurethane synthetic leather sample. Compared with Example 1, in Comparative Example 1, with the same amount of composite modifier and without hindered phenol in the composite modifier, the increased amount of graphene modifier resulted in enhanced thermal insulation properties.

[0146] Table 2

[0147]

[0148] As shown in Table 2, the polyurethane transfer film prepared by this invention exhibits excellent far-infrared heating performance. The introduction of graphene effectively improves the far-infrared heating performance of the polyurethane transfer film. Compared with Example 1, in Comparative Example 1, with the same amount of composite modifier and without hindered phenol in the composite modifier, the increased amount of graphene modifier actually enhanced the far-infrared heating performance.

[0149] (2) UV resistance: The polyurethane synthetic leather sample obtained by the method in test example (1) was irradiated under 380nm ultraviolet light for 4000h, and the color change value before and after irradiation, i.e., color difference (ΔE), was measured. The measurement results are shown in Table 3.

[0150] Table 3

[0151]

[0152] Table 3 shows that the polyurethane transfer film prepared by this invention has good UV resistance. The addition of the UV absorber 4-propenoxy-2-hydroxybenzophenone can effectively improve the UV resistance of the polyurethane transfer film. Compared with Example 1, in Comparative Example 1, with the same amount of composite modifier and without hindered phenol in the composite modifier, the increased amount of UV absorber actually enhanced the UV resistance.

[0153] (3) Antioxidant performance: After the slurry prepared in step (1) of Example-3 and Comparative Example 1-2 was poured, it was solidified, washed, squeezed and dried in sequence according to the methods in Example 1-3 and Comparative Example 1-2. Then it was cut into dumbbell-shaped test samples as shown in standard GB / T528. The tensile strength retention rate of the test samples after thermo-oxidative aging at 140℃ for 1000h was measured. The test method was based on ISO527-2012, and the tensile rate was 5mm / min. The test results are shown in Table 4.

[0154] Table 4

[0155]

[0156] As shown in Table 4, the polyurethane transfer film prepared by this invention has good antioxidant properties. The introduction of hindered phenolic antioxidants can effectively improve the antioxidant properties of polyurethane transfer films. Compared with Example 1, in Comparative Example 1, the composite modifier does not contain chloropropenyl-modified hindered phenol, and no hindered phenolic antioxidants are introduced, resulting in a significant decrease in antioxidant properties.

[0157] (4) Hydrolysis resistance: The test sample obtained by the method in test example (3) was boiled in water at 120℃ for 200h, and the tensile strength retention rate of the test sample was measured. The test method refers to ISO527-2012, and the tensile rate is 5mm / min. The test results are shown in Table 5.

[0158] Table 5

[0159]

[0160] Table 5 shows that the polyurethane transfer film prepared by this invention has good hydrolysis resistance. During the preparation of the composite modifier, the hindered phenolic antioxidant 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazide reacts with 2-chloropropenyl isothiocyanate. While introducing an alkenyl group into the molecular structure of the hindered phenolic antioxidant, the carbodiimide group generated by the reaction of the hydrazide group and the isothiocyanate group has excellent hydrolysis resistance, effectively improving the hydrolysis resistance of polyester-type polyurethane, and thus improving the hydrolysis resistance of the polyurethane transfer film. Compared with Example 1, in Comparative Example 1, the composite modifier did not contain chloropropenyl-modified hindered phenol, i.e., no carbodiimide was introduced, resulting in a significant decrease in hydrolysis resistance. In Comparative Example 2, the alkenyl-modified hindered phenol was prepared by reacting 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazide with 3-propenyl isocyanate, also without the introduction of carbodiimide, resulting in a significant decrease in the hydrolysis resistance of the polyurethane transfer film.

[0161] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A far-infrared heat-insulating polyurethane transfer film containing graphene, characterized in that, It includes a support layer, a polyurethane transfer layer, and an adhesive layer, wherein the polyurethane transfer layer is located on one side of the support layer and the adhesive layer is located on the other side of the polyurethane transfer layer; The support layer includes a PET release film layer; The adhesive layer includes a hot melt adhesive film layer; The raw materials for preparing the polyurethane transfer layer include: polyurethane resin, organic solvent, organic pigment, and composite modifier; The mass ratio of the polyurethane resin, organic solvent, organic pigment, and composite modifier is 100:(35-45):(2-3):(4-8); The composite modifier is prepared by the following steps: S1. Preparation of alkenyl-modified graphene oxide and chloropropenyl-modified hindered phenol; The preparation of alkenyl-modified graphene oxide includes: Carboxylated graphene oxide was reacted with γ-methacryloyloxypropyltrimethoxysilane to prepare alkenyl-modified graphene oxide. The preparation of chloropropenyl-modified hindered phenols includes: 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine and 2-chloropropenyl isothiocyanate were added to ethanol and reacted. After the reaction was completed, the mixture was cooled, filtered, and recrystallized to obtain thiourea-modified hindered phenol. Thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water were mixed and reacted. After the reaction was completed, the mixture was separated, purified, and dried to obtain chloropropenyl-modified hindered phenol. A composite modifier is prepared by reacting S2, alkenyl-modified graphene oxide, chloropropenyl-modified hindered phenol, and 4-propenoxy-2-hydroxybenzophenone.

2. The far-infrared heat-insulating polyurethane transfer film containing graphene according to claim 1, characterized in that, The polyurethane resin includes polyether-type polyurethane resin and polyester-type polyurethane resin; The mass ratio of the polyether-type polyurethane resin to the polyester-type polyurethane resin is (0.5-2):1; The organic solvent includes N,N-dimethylformamide.

3. The far-infrared heat-insulating polyurethane transfer film containing graphene according to claim 1, characterized in that, In step S1, the preparation of alkenyl-modified graphene oxide specifically includes: Carboxylated graphene oxide was added to ethanol, ultrasonically dispersed, and the pH was adjusted to 5-6. A mixture of γ-methacryloxypropyltrimethoxysilane and ethanol was added dropwise. After the addition was complete, the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain alkenyl-modified graphene oxide. The mass ratio of carboxylated graphene oxide, ethanol, and γ-methacryloxypropyltrimethoxysilane-ethanol mixture is 1:(50-60):(80-120), and the reaction conditions are 50-70℃ for 20-30h.

4. The far-infrared heat-insulating polyurethane transfer film containing graphene according to claim 3, characterized in that, The carboxylated graphene oxide is prepared by the following steps: Graphene oxide was dispersed in deionized water and ultrasonically dispersed to obtain a graphene oxide dispersion. Sodium hydroxide and monochloroacetic acid were added to the graphene oxide dispersion and reacted. After the reaction was completed, the mixture was filtered, washed, and dried to obtain carboxylated graphene oxide. The mass ratio of graphene oxide, deionized water, sodium hydroxide, and monochloroacetic acid is 0.1:(80-120):(5.5-6.5):(4.5-5.5), and the reaction conditions are ultrasonic reaction at a frequency of 60-80kHz for 2.5-3.5h.

5. The far-infrared heat-insulating polyurethane transfer film containing graphene according to claim 1, characterized in that, In S1: when preparing thiourea-modified hindered phenol, the mass ratio of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylhydrazine, 2-chloropropenyl isothiocyanate, and ethanol is 29.2:(14-16):(400-600), and the reaction conditions are reflux reaction at 85-95℃ for 4-5h. When preparing chloropropenyl-modified hindered phenol, the mass ratio of thiourea-modified hindered phenol, mercuric oxide, chloroform, and deionized water is 4.3:(8.2-8.5):(205-220):(135-145), and the reaction conditions are stirring at room temperature for 45-50 h.

6. The far-infrared heat-insulating polyurethane transfer film containing graphene according to claim 1, characterized in that, In step S2, the preparation of the composite modifier specifically includes: 4-Acryloxy-2-hydroxybenzophenone was added to toluene and stirred until dissolved to obtain a 4-acryloxy-2-hydroxybenzophenone solution. Benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol were added to the 4-acryloxy-2-hydroxybenzophenone solution, stirred and dispersed, and then heated to a set temperature for reaction. After the reaction was completed, the mixture was rotary evaporated, purified, and dried to obtain the composite modifier. The mass ratio of 4-propenoxy-2-hydroxybenzophenone, toluene, benzoyl peroxide, alkenyl-modified graphene oxide, and chloropropenyl-modified hindered phenol is (50.8-55):(800-1000):(1.8-4.2):(48-52):(42.6-44), and the reaction conditions are to react at a set temperature for 1-2 hours. The set temperature is 90-100℃.

7. A method for preparing a graphene-containing far-infrared heat-insulating polyurethane transfer film as described in any one of claims 1-6, characterized in that, Includes the following steps: Step (1): Dissolve polyurethane resin in an organic solvent, add organic pigments and composite modifiers, stir and mix to obtain a slurry; coat the slurry onto the surface of a PET release film, and after coagulation, washing and drying, form a polyurethane transfer layer; Step (2): A hot melt adhesive film is bonded to the surface of the polyurethane transfer layer, and an adhesive layer is formed by pressing and cooling to obtain a far-infrared warming polyurethane transfer film containing graphene. The graphene-containing far-infrared heat-insulating polyurethane transfer film includes a support layer, a polyurethane transfer layer, and an adhesive layer. The support layer is a PET release film layer, and the adhesive layer is a hot melt adhesive film layer.

8. The method for preparing the graphene-containing far-infrared heat-insulating polyurethane transfer film according to claim 7, characterized in that, In step (1), the coating amount of the slurry is 180-240 g / m. 2 The solidification conditions are as follows: solidify in 16wt%-20wt% N,N-dimethylformamide aqueous solution at room temperature for 15-20 min; the water washing conditions are as follows: water washing at 60-80℃, squeezing once every 5 min during the water washing process, squeezing 5-10 times; the drying conditions are as follows: drying at 100-120℃ for 10-20 min.

9. The method for preparing a graphene-containing far-infrared heat-insulating polyurethane transfer film according to claim 7, characterized in that, In step (2), the thickness of the hot melt adhesive film is 0.1-0.2 mm, the softening point of the hot melt adhesive film is 120-130℃, and the pressing pressure is 4-6 MPa.

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