Cooling leather and treatment process

Abstract

The invention provides cooling leather and a treatment process, and belongs to the technical field of cooling leathes.The cooling leather treatment process comprises the following steps that S1, modified boron nitride is prepared, specifically, S1, modified boron nitride is prepared; s2, polyurethane synthetic leather is selected as a base material and subjected to plasma cleaning, surface impurities are removed, and the surface is activated; s3, the surface of the base material is coated with waterborne polyurethane slurry containing 3%-8% of modified boron nitride; s4, after the heat conduction bottom layer is cured, embossing is conducted at the temperature of 160-170 DEG C; s5, plasma cleaning or short-time infrared heating is conducted on the embossed layer; s6, spraying a microcapsule phase change material on the surface of the activated embossing layer; s7, covering a fluorocarbon resin surface layer containing 1-3% of modified boron nitride; s8, carrying out secondary echelon cooling after the surface layer is cured; the h-BN is subjected to double-layer modification through polydopamine-hyperbranched polyethyleneimine (HPEI), and hydrophilic modification of the surface of the filler is realized at low temperature, so that the heat conductivity coefficient is increased, and meanwhile, the mechanical property of the material is kept stable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cooling leather, in particular to a cooling leather and a processing technology. BACKGROUND

[0002] With the increasing demand for comfort and functionality, intelligent temperature control leather is increasingly widely used in fields such as automobile seats, smart home, sports equipment, etc. For example, composite leather combined with phase change materials and thermoelectric materials can achieve energy saving and emission reduction through dynamic temperature adjustment.

[0003] Polyurethane synthetic leather is widely used in fields such as automotive interiors, furniture decoration, shoe materials, etc. due to its excellent wear resistance, skin simulation and processing adaptability. However, the thermal conductivity of traditional polyurethane synthetic leather is usually low, and it is difficult to quickly disperse the heat on the surface in a high temperature environment, such as a summer car or a high load use scenario, resulting in local temperature accumulation and significantly reducing the use comfort.

[0004] However, traditional leather materials have limited thermal conductivity and are difficult to quickly disperse the heat on the surface in a high temperature environment, resulting in reduced wearing comfort. Although there have been attempts to add thermal conductive fillers or introduce phase change materials, there are generally technical bottlenecks such as low thermal conductivity, weak interface bonding, poor cooling effect, and easy deformation, for example, traditional boron nitride is easy to agglomerate, resulting in discontinuous thermal conduction network, rough surface treatment process of the substrate, and inability to effectively activate the surface.

[0005] To improve the thermal conductivity of polyurethane synthetic leather, the industry generally adopts the technical path of adding thermal conductive fillers, but existing technologies have defects, such as poor dispersion of thermal conductive fillers, strong hydrophobicity of inorganic fillers such as hexagonal boron nitride (h-BN), which easily forms agglomerates in the polyurethane matrix, resulting in broken thermal conduction network, and h-BN needs to be added in an amount of more than 15% in polyurethane to form a continuous thermal conduction path, but this will cause the mechanical properties of the material to decrease, and high temperature treatment is required for modification by traditional silane coupling agents, which has poor compatibility with the polyurethane processing process, and there is still micro-phase separation between the modified filler and the resin interface

[0006] In view of the above problems, the present application proposes a cooling leather and a processing technology, which modifies h-BN through a double layer of polydopamine and hyperbranched polyethyleneimine (HPEI), realizes surface hydrophilization modification of the filler at low temperature (80℃), enhances the dispersion of the filler through hydrogen bonding and covalent bonding of the polydopamine coating layer, and further reduces the agglomeration of the filler through the branched structure of HPEI, so as to improve the thermal conductivity while keeping the mechanical properties of the material stable. SUMMARY

[0007] The present application aims to solve the above problems of existing technologies and proposes a cooling leather and a processing technology.

[0008] The object of the present application can be realized by the following technical solutions:

[0009] A cooling leather and processing technology, comprising the following steps:

[0010] S1: modified boron nitride preparation, the preparation step comprising:

[0011] S11: the hexagonal boron nitride (h-BN) powder is subjected to plasma cleaning;

[0012] S12: configure Tris-HCL buffer solution, add dopamine hydrochloride and hexagonal boron nitride powder, stir at room temperature for 24 h, and centrifugal wash to obtain a polydopamine adhesion layer;

[0013] S13: the polydopamine adhesion layer obtained in step S12 is dispersed in an ethanol solution, 5% of the mass of the polydopamine adhesion layer is added as hyperbranched polyethyleneimine (HPEI), the polydopamine coating rate is 10-20% of the mass of h-BN, and after refluxing at 80 DEG C for 2-4 hours, centrifugal wash is performed to obtain modified boron nitride;

[0014] S2: select a polyurethane synthetic leather as a substrate, and perform plasma cleaning on the substrate to remove surface impurities and activate the surface;

[0015] S3: coat the surface of the substrate with an aqueous polyurethane slurry containing 3-8% modified boron nitride, the coating amount is 50-70 g / m 2 , and the heat-conducting bottom layer is formed by curing at 100 DEG C;

[0016] S4: after curing of the heat-conducting bottom layer, embossing is performed at 160-170 DEG C, and then gradient cooling is adopted, and the temperature is sequentially cooled through three holding zones of 130-150 DEG C, 110-130 DEG C and 70-90 DEG C, and then to room temperature;

[0017] S5: the embossed layer is subjected to plasma cleaning or short-time infrared heating (60-80 DEG C) to activate the surface hydroxyl groups and enhance the binding force with the phase change material;

[0018] S6: spray a microcapsule phase change material on the surface of the activated embossed layer, the coating amount is 20-30 g / m 2 , and pre-curing is performed at 30-40 DEG C for 3-5 minutes;

[0019] S7: cover a fluorocarbon resin top layer containing 1-3% modified boron nitride, the coating amount is 10-15 g / m 2 , and after curing to a tack-free state at 80 DEG C, immediately enter the cooling process of S8;

[0020] S8: After the surface layer is cured, secondary stepwise cooling is performed, and after being kept at 120℃ for 30 min, the temperature is decreased to 100℃ at a rate of ≤3℃ / min, and after being kept at 100℃ for 30 min, the temperature is decreased to 90℃ at a rate of ≤3℃ / min and naturally cooled, thereby forming a continuous temperature curve with the stepwise cooling process in step S4.

[0021] Preferably, the modified boron nitride aqueous polyurethane slurry in step S3 comprises the following raw materials in parts by weight:

[0022] polypropylene oxide polyol 70-80 parts, polyneopentylene succinate 20-30 parts, modified boron nitride 3-8 parts, isophorone diisocyanate 35-40 parts, dimethylol propionic acid 6-8 parts, triethylamine 4-5 parts, acetone 40-50 parts, defoaming agent 0.3-0.5 parts, thickening agent 1.5-2.0 parts, leveling agent 0.2-0.3 parts,

[0023] wherein the defoaming agent is selected from a polyether-modified silicone defoaming agent or a silica composite silicone defoaming agent, the thickening agent is a non-ionic polyurethane associated thickening agent, and the leveling agent is a fluorine-modified acrylate leveling agent.

[0024] Preferably, the plasma cleaning in step S11 uses oxygen / argon mixed gas, the power is 200-400 W, the power density is 0.5-1.0 W / cm 2 , the processing time is 5-15 minutes, the vacuum degree is controlled at 50-200 Pa, the pH value of the Tris-HCL buffer in step S12 is 8.5-9.5, the concentration of dopamine hydrochloride is 2-4 g / L, and the mass / volume ratio of hexagonal boron nitride powder to buffer is 1:(20-50).

[0025] Preferably, the embossing process in step S4 uses a metal roller with a microstructure groove, the embossing temperature is 160-170℃, and the pressure is 0.3-0.5 MPa.

[0026] Preferably, the microcapsule phase change material in step S6 is a paraffin or a fatty acid, the phase change temperature is 35-45℃, the microcapsule particle size is 5-15 μm, and the spraying pressure is 0.2-0.4 MPa.

[0027] Preferably, the slurry preparation method comprises:

[0028] S31: First, mix polypropylene oxide polyol and polyneopentylene succinate uniformly at 70-80℃;

[0029] S32: Add modified boron nitride, isophorone diisocyanate, and dimethylol propionic acid in sequence;

[0030] S33: heating to 85-90℃ for 2 hours, after cooling, adding triethylamine for neutralization, then adding acetone, defoaming agent, thickening agent and leveling agent, stirring for 30 minutes, and removing acetone by distillation under reduced pressure after the reaction is completed.

[0031] Preferably, the plasma cleaning in step S5 uses a mixed gas of oxygen and argon with a volume ratio of 1:1 to 1:3, a power density of 0.5-1.2 W / cm 2 , a processing time of 30-90 seconds; or the wavelength of the infrared heating is 2.5-3.5 μm, the irradiation intensity is 300-500 W / m 2 , and the heating time is 45-120 seconds.

[0032] Preferably, the fluorocarbon resin surface layer in step S7 contains perfluorooctyl ethyl acrylate, and the fluorine content is 15-20 wt%, and the modified boron nitride is pretreated with perfluorooctyl triethoxysilane.

[0033] Compared with the prior art, the medium frequency heat treatment process has the following beneficial effects:

[0034] 1. The cooling leather and treatment process provided by the application realizes the hydrophilic modification of the filler surface at low temperature through the double-layer modification of h-BN by polydopamine-hyperbranched polyethyleneimine (HPEI), enhances the dispersibility of the filler through the hydrogen bond and covalent bond action of the polydopamine coating layer, further reduces the agglomeration of the filler through the branched structure of HPEI, and improves the thermal conductivity while keeping the mechanical properties of the material stable.

[0035] 2. The cooling leather and treatment process provided by the application significantly enhances the bonding force between the thermal conductive bottom layer and the substrate through the activation of the substrate surface by plasma cleaning, the removal of impurities and the introduction of active groups, and the hydrophilic modification of the modified filler.

[0036] 3. The cooling leather and treatment process provided by the application ensures efficient heat absorption in the comfortable temperature range of the human body by selecting phase change temperature microcapsules, realizes uniform distribution through the spraying process, and improves the cooling performance through the synergistic effect of the modified h-BN thermal conductive network.

[0037] 4. The cooling leather and treatment process provided by the application strictly controls the deformation rate through the three-stage gradient cooling process combined with the difference control of the thermal expansion coefficients of the embossed layer and the bottom layer, avoids interface peeling by slowly releasing thermal stress, and improves the product qualification rate.

[0038] In summary, the cooling leather and treatment process provided by the application realizes the synergistic improvement of the thermal conductivity, cooling effect and structural stability of the cooling leather through key technical innovations such as filler modification, interface optimization, phase change material adaptation and gradient cooling. DETAILED DESCRIPTION

[0039] The following are specific embodiments of the present application, which further describe the technical solutions of the present application, but the present application is not limited to these embodiments.

[0040] Embodiment one:

[0041] A cooling leather and processing technology, comprising the following steps:

[0042] S1: preparation of modified boron nitride, the preparation steps comprising:

[0043] S11: plasma cleaning of hexagonal boron nitride (h-BN) powder, oxygen / argon volume ratio 1:2, total flow rate 50 sccm, power 300 W, vacuum degree 100 Pa, treatment time 10 min;

[0044] S12 polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), adding dopamine hydrochloride to a concentration of 3 g / L, adding 5 g of h-BN powder at a ratio of h-BN: buffer = 1:30 (g / mL), room temperature mechanical stirring (200 rpm) for 24 h, centrifugation at 8000 rpm x 10 min, washing with deionized water 3 times, freeze-drying to obtain polydopamine coated h-BN, coating rate 15%;

[0045] S13 hyperbranched polyethyleneimine grafting: dispersing polydopamine coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), adding HPEI (5% of the mass of h-BN), 80°C oil bath refluxing for 3 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, washing with ethanol 2 times, freeze-drying to obtain modified boron nitride;

[0046] S2: selecting polyurethane synthetic leather as substrate, fixing on the platform, spray gun distance from substrate 10 mm, vertical scanning to activate the surface, oxygen / helium mixed gas (volume ratio 1:4), power 500 W, scanning speed 5 mm / s, processing 2 times;

[0047] S3: coating modified boron nitride water-based polyurethane slurry on the surface of the substrate, coating amount 60 g / m 2 , coating gap 50 μm, 100°C hot air circulation oven curing for 30 min, slurry preparation comprising:

[0048] 75 parts of polypropylene oxide polyol and 25 parts of polybutylene succinate are stirred at 80°C at 300 rpm for 30 min, 5 parts of modified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylol propionic acid are sequentially added, the temperature is raised to 85°C and reacted for 2 h, the temperature is lowered to 50°C, 4 parts of triethylamine is added and neutralized for 30 min, then 50 parts of acetone, 0.4 parts of polyether modified silicone defoaming agent, 1.8 parts of non-ionic polyurethane thickening agent, and 0.25 parts of fluorine modified acrylate leveling agent are added, stirred for 30 min, and the acetone is removed by vacuum distillation at 60°C / 15 kPa to obtain a slurry with a solid content of 45%;

[0049] S4: After the heat-conducting bottom layer is cured, embossing is performed at a temperature of 165°C, a linear pressure of 0.4 MPa, and a roller speed of 2 m / min, and immediately after embossing, a three-stage heat preservation zone is entered: first stage: 140°C x 5 min (air cooling); second stage: 120°C x 5 min (natural cooling); third stage: 80°C x 5 min (room temperature standing);

[0050] S5: Plasma cleaning is performed under the following conditions: O2 / Ar volume ratio 1:1, power density 0.8 W / cm 2 , vacuum degree 80 Pa, treatment time 60 s, or short-time infrared heating is performed under the following conditions: irradiation intensity 400 W / m 2 , heating time 60 s, substrate surface temperature raised to 65°C;

[0051] S6: After the embossed layer is activated, a paraffin microcapsule phase change material is sprayed on the surface of the embossed layer, the spraying pressure is 0.3 MPa, the substrate temperature is 35°C, the coating amount is 25 g / m 2 , and 35°C hot air circulation pre-curing is performed for 4 min;

[0052] S7: A fluorocarbon resin top layer covering the modified boron nitride is prepared from perfluoro-octyl ethyl acrylate resin (fluorine content 18%) and 1% perfluoro-octyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15 s with isopropyl alcohol, and the coating amount is 12 g / m 2 , 80°C hot air circulation is performed for 10 min to cure to tack-free;

[0053] S8: After the top layer is cured, secondary gradient cooling is performed: 120°C heat preservation for 30 min → 100°C at a rate of 2°C / min → heat preservation for 30 min → 90°C at a rate of 2°C / min → natural cooling.

[0054] Example Two:

[0055] A cooling leather and processing technology, comprising the following steps:

[0056] S1: Preparation of modified boron nitride, the preparation steps include:

[0057] S11: Plasma cleaning of hexagonal boron nitride (h-BN) powder, oxygen / argon volume ratio 1:2, total flow rate 50 sccm, power 200 W, vacuum degree 50 Pa, treatment time 5 min.

[0058] S12: Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), add dopamine hydrochloride to a concentration of 2 g / L, add h-BN powder at a ratio of h-BN:buffer = 1:20 (g / mL), mechanical stirring (200 rpm) at room temperature for 24 h, centrifugation at 8000 rpm x 10 min, then wash with deionized water 3 times, freeze-drying to obtain polydopamine-coated h-BN, coating rate 10%;

[0059] S13: Hyperbranched polyethyleneimine grafting: disperse the polydopamine-coated h-BN in 200 mL ethanol (concentration 2.5 wt%), add HPEI (5% of the mass of h-BN), 80°C oil bath reflux for 2 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, then wash with ethanol 2 times, freeze-drying to obtain modified boron nitride;

[0060] S2: Select polyurethane synthetic leather as substrate, fix on platform, spray gun distance from substrate 10 mm, activate surface by vertical scanning, oxygen / helium mixed gas (volume ratio 1:4), power 500 W, scanning speed 5 mm / s, process 2 times;

[0061] S3: Apply modified boron nitride waterborne polyurethane slurry on the surface of the substrate, coating amount 50 g / m 2 , coating gap 50 μm, 100°C hot air circulation oven curing for 25 min, slurry preparation includes:

[0062] 75 parts of polypropylene glycol and 25 parts of polybutylene succinate are stirred at 300 rpm at 80°C for 30 min, then 3 parts of modified boron nitride, 38 parts of isophorone diisocyanate, 7 parts of dimethylol propionic acid are added in turn, heated to 85°C for 2 h, cooled to 50°C, added 4 parts of triethylamine for neutralization for 30 min, then added 50 parts of acetone, 0.3 parts of silica composite defoaming agent, 1.8 parts of non-ionic polyurethane thickener, 0.25 parts of fluorine modified acrylic ester leveling agent, stirred for 30 min, removed acetone under reduced pressure at 60°C / 15 kPa to obtain a slurry with a solid content of 45%;

[0063] S4: After the heat-conducting bottom layer is cured, embossing is performed at a temperature of 160°C, a linear pressure of 0.3 MPa, and a roller speed of 2 m / min, and immediately after embossing, a three-stage heat preservation zone is entered: the first stage: 130°C x 5 min (air cooling); the second stage: 110°C x 5 min (natural cooling); and the third stage: 70°C x 5 min (room temperature standing);

[0064] S5: Plasma cleaning is performed under the conditions of an O2 / Ar volume ratio of 1:1, a power density of 0.8 W / cm 2 , a vacuum degree of 80 Pa, and a processing time of 60 s, or short-time infrared heating is performed under the conditions of an irradiation intensity of 400 W / m 2 , a heating time of 60 s, and a substrate surface temperature of 65°C;

[0065] S6: Microcapsule phase change materials are sprayed on the surface of the activated embossed layer, the microcapsules are fatty acid type, the spraying pressure is 0.3 MPa, the substrate temperature is 35°C, the coating amount is 20 g / m 2 , and 30°C hot air circulation pre-curing is performed for 5 min;

[0066] S7: A fluorocarbon resin top layer of modified boron nitride is covered, the fluorocarbon resin top layer is prepared from perfluorooctyl ethyl acrylate resin (fluorine content 18%) and 1% perfluorooctyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15 s by isopropanol, and the coating amount is 12 g / m 2 . 80°C hot air circulation is performed for 10 min to cure to a tack-free state;

[0067] S8: After the top layer is cured, secondary gradient cooling is performed, 120°C heat preservation for 30 min → reduction to 100°C at a rate of 2°C / min → heat preservation for 30 min → reduction to 90°C at a rate of 2°C / min → natural cooling.

[0068] Example Three

[0069] A cooling leather and processing technology, comprising the following steps:

[0070] S1: Modified boron nitride preparation, the preparation steps comprising:

[0071] S11: Hexagonal boron nitride (h-BN) powder is subjected to plasma cleaning under the conditions of an oxygen / argon volume ratio of 1:2, a total flow rate of 50 sccm, a power of 400 W, a vacuum degree of 200 Pa, and a processing time of 15 min.

[0072] S12 Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), add dopamine hydrochloride to a concentration of 4 g / L, add h-BN powder at a ratio of h-BN: buffer = 1:50 (g / mL), mechanical stirring (200 rpm) at room temperature for 24 h, centrifugation at 8000 rpm x 10 min, then washed with deionized water for 3 times, freeze-drying to obtain polydopamine coated h-BN, coating rate 20%;

[0073] S13 Hyperbranched polyethyleneimine grafting: disperse the polydopamine coated h-BN in 200 mL ethanol (concentration 2.5 wt%), add HPEI (5% of the mass of h-BN), 80°C oil bath reflux for 4 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, then washed with ethanol for 2 times, freeze-drying to obtain modified boron nitride;

[0074] S2: Select polyurethane synthetic leather as substrate, fix on the platform, spray gun distance from substrate 10 mm, activate the surface by vertical scanning, oxygen / helium mixed gas (volume ratio 1:4), power 500 W, scanning speed 5 mm / s, process 2 times;

[0075] S3: Apply modified boron nitride water-based polyurethane slurry on the surface of the substrate, coating amount 70 g / m 2 , coating gap 50 μm, 100°C hot air circulation oven curing for 35 min, slurry preparation includes:

[0076] 75 parts of polypropylene oxide polyol and 25 parts of polybutylene succinate neopentyl glycol are stirred at 80°C at 300 rpm for 30 min, 9 parts of modified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylol propionic acid are added in turn, the temperature is raised to 85°C and reacted for 2 h, the temperature is lowered to 50°C, 4 parts of triethylamine is added and neutralized for 30 min, then 50 parts of acetone, 0.5 parts of polyether modified silicone defoamer, 1.8 parts of non-ionic polyurethane thickener, and 0.25 parts of fluorine modified acrylate leveling agent are added, stirred for 30 min, and the acetone is removed by vacuum distillation at 60°C / 15 kPa to obtain a slurry with a solid content of 45%;

[0077] S4: After curing the heat-conducting bottom layer, embossing is performed at a temperature of 170°C, a line pressure of 0.5 MPa, and a roller speed of 2 m / min, and immediately after embossing, a three-stage heat preservation zone is entered: first stage: 150°C x 5 min (air cooling); second stage: 130°C x 5 min (natural cooling); third stage: 90°C x 5 min (room temperature standing);

[0078] S5: Plasma cleaning is performed under the following conditions: O2 / Ar volume ratio 1:1, power density 0.8 W / cm 2 , vacuum degree 80 Pa, processing time 60 s, or under the following conditions: irradiation intensity 400 W / m2 Short-time infrared heating was performed at a heating time of 60 s and a substrate surface temperature of 65 °C.

[0079] S6: Spraying paraffin microcapsule phase change material on the surface of the embossed layer after activation, spraying pressure 0.3 MPa, substrate temperature 35 °C, coating amount 25 g / m 2 , 35 °C hot air circulation pre-curing for 4 min;

[0080] S7: Covering the fluorocarbon resin top layer of modified boron nitride, the fluorocarbon resin top layer is made of perfluoro octyl ethyl acrylate resin (fluorine content 18%), 1% perfluoro octyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15 s by isopropyl alcohol, and the coating amount is 12 g / m 2 , 80 °C hot air circulation for 10 min to dry to the touch;

[0081] S8: After curing the top layer, secondary gradient cooling is performed, 120 °C for 30 min, then reduced to 100 °C at a rate of 2 °C / min, 30 min, then reduced to 90 °C at a rate of 2 °C / min, and then naturally cooled.

[0082] Example Four:

[0083] A cooling leather and processing technology, comprising the following steps:

[0084] S1: Preparation of modified boron nitride, the preparation steps comprising:

[0085] S11: Plasma cleaning of hexagonal boron nitride (h-BN) powder, oxygen / argon volume ratio 1:2, total flow rate 50 sccm, power 300 W, vacuum degree 100 Pa, treatment time 10 min.

[0086] S12: Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), adding dopamine hydrochloride to a concentration of 3 g / L, adding 5 g of h-BN powder at a ratio of h-BN:buffer = 1:30 (g / mL), room temperature mechanical stirring (200 rpm) for 24 h, centrifugation at 8000 rpm x 10 min, and then washing with deionized water for 3 times, freeze-drying to obtain polydopamine coated h-BN, coating rate 15%;

[0087] S13: Hyperbranched polyethyleneimine grafting: dispersing the polydopamine coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), adding HPEI (5% of the mass of h-BN), 80 °C oil bath refluxing for 3 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, and then washing with ethanol for 2 times, freeze-drying to obtain modified boron nitride;

[0088] S2: Select polyurethane synthetic leather as substrate, fix on platform, spray gun distance 10mm, vertical scanning active surface, oxygen / helium mixed gas (volume ratio 1:4), power 500W, scanning speed 5mm / s, process 2 times;

[0089] S3: Coating modified boron nitride waterborne polyurethane slurry on the surface of the substrate, coating amount 60g / m 2 , coating gap 50μm, 100℃ hot air circulation oven curing 30min, slurry preparation includes:

[0090] 75 parts of polypropylene glycol polyol and 25 parts of polybutylene succinate were stirred at 80℃ for 30min at 300rpm, 5 parts of modified boron nitride, 38 parts of isophorone diisocyanate, 7 parts of dimethylol propionic acid were added in turn, heated to 85℃ for 2h, cooled to 50℃, added 4 parts of triethylamine for 30min, then added 50 parts of acetone, 0.4 parts of polyether modified silicone defoamer, 1.8 parts of non-ionic polyurethane thickener, 0.25 parts of fluorine modified acrylate leveling agent, stirred for 30min, removed acetone under reduced pressure at 60℃ / 15kPa to obtain a slurry with solid content of 45%;

[0091] S4: After curing the heat-conducting bottom layer, embossing was carried out at a temperature of 165℃, a linear pressure of 0.4MPa, and a roller speed of 2m / min. Immediately after embossing, it entered the three-stage heat preservation zone: first stage: 140℃×5min (air cooling); second stage: 120℃×5min (natural cooling); third stage: 80℃×5min (room temperature standing);

[0092] S5: Plasma cleaning under the conditions of O2 / Ar volume ratio 1:3, power density 1.2W / cm 2 , vacuum degree 80Pa, processing time 90s, or short-time infrared heating under the conditions of irradiation intensity 500W / m 2 , heating time 120s, substrate surface temperature rising to 70℃;

[0093] S6: Spraying fatty acid microcapsule phase change material on the surface of the activated embossed layer, spraying pressure 0.3MPa, substrate temperature 35℃, coating amount 25g / m 2 , 35℃ hot air circulation pre-curing 4min;

[0094] S7: Covering modified boron nitride fluorocarbon resin top layer, fluorocarbon resin top layer is made of perfluoro octyl ethyl acrylate resin (fluorine content 18%), modified boron nitride pretreated with 1% perfluoro octyl triethoxysilane, viscosity adjusted to 15s by isopropyl alcohol, through automatic spraying machine, coating amount 12g / m 2 , 80℃ hot air circulation 10min curing to dry to the touch;

[0095] S8: After the surface layer is cured, secondary gradient cooling is performed, 120°C for 30 min, then reduced to 100°C at a rate of 2°C / min, 30 min for holding, then reduced to 90°C at a rate of 2°C / min, and then naturally cooled.

[0096] Comparative Example 1

[0097] A cooling leather and treatment process, comprising the following steps:

[0098] S1: Preparation of modified boron nitride, the preparation steps comprising:

[0099] S11: Weigh 5 g of unwashed hexagonal boron nitride (h-BN) powder.

[0100] S12: Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), add dopamine hydrochloride to a concentration of 3 g / L, add h-BN powder at a ratio of h-BN:buffer = 1:30 (g / mL), mechanical stirring (200 rpm) at room temperature for 24 h, centrifuge at 8000 rpm x 10 min, then wash with deionized water for 3 times, freeze-drying to obtain polydopamine-coated h-BN, the coating rate is 15%;

[0101] S13: Hyperbranched polyethyleneimine grafting: disperse the polydopamine-coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), add HPEI (5% of the mass of h-BN), 80°C oil bath reflux for 3 h, mechanical stirring (300 rpm), centrifuge at 10000 rpm x 15 min, then wash with ethanol for 2 times, freeze-drying to obtain modified boron nitride;

[0102] S2: Select polyurethane synthetic leather as the substrate, wipe the surface with a dust-free cloth dipped in anhydrous ethanol, and naturally air dry for 5 min;

[0103] S3: Apply modified boron nitride water-based polyurethane slurry on the surface of the substrate, the coating amount is 60 g / m 2 , the coating gap is 50 μm, and the slurry is cured in a hot air circulation oven at 100°C for 30 min, the slurry preparation comprising:

[0104] 75 parts of polypropylene glycol and 25 parts of polybutylene succinate are stirred at 300 rpm at 80°C for 30 min, then 5 parts of modified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylol propionic acid are added in sequence, the temperature is raised to 85°C for reaction for 2 h, the temperature is lowered to 50°C, 4 parts of triethylamine is added for neutralization for 30 min, then 50 parts of acetone, 0.4 parts of polyether modified silicone defoaming agent, 1.8 parts of non-ionic polyurethane thickener, and 0.25 parts of fluorine modified acrylate leveling agent are added, stirred for 30 min, and the acetone is removed by distillation under reduced pressure at 60°C / 15 kPa to obtain a slurry with a solid content of 45%.

[0105] S4: After the thermally conductive base layer has cured, embossing is performed at a temperature of 165℃, a linear pressure of 0.4MPa, and a roller speed of 2m / min. Immediately after embossing, the material enters a three-stage heat preservation zone: Stage 1: 140℃×5min (air cooling); Stage 2: 120℃×5min (natural cooling); Stage 3: 80℃×5min (room temperature standing).

[0106] S5: With an O2 / Ar volume ratio of 1:1, the power density is 0.8 W / cm³. 2 Plasma cleaning is performed under conditions of 80 Pa vacuum and 60 s processing time, or under irradiation intensity of 400 W / m². 2 Short-term infrared heating is performed under the condition that the heating time is 60 seconds and the surface temperature of the substrate rises to 65°C.

[0107] S6: Spray paraffin microcapsule phase change material onto the activated embossed layer surface at a spraying pressure of 0.3 MPa, a substrate temperature of 35°C, and a coating weight of 25 g / m². 2 Pre-curing with hot air circulation at 35℃ for 4 minutes;

[0108] S7: A fluorocarbon resin topcoat with modified boron nitride. The fluorocarbon resin topcoat is made of perfluorooctyl ethyl acrylate resin (fluorine content 18%), with 1% perfluorooctyltriethoxysilane pretreated modified boron nitride added. The viscosity is adjusted to 15s with isopropanol, and the coating is applied using an automatic spraying machine at a coating amount of 12g / m². 2 Curing is achieved by circulating hot air at 80℃ for 10 minutes until surface dry.

[0109] S8: After the surface layer is cured, a second-stage cooling process is carried out: keep at 120℃ for 30 minutes → cool down to 100℃ at a rate of 2℃ / min → keep at 120℃ for 30 minutes → cool down to 90℃ at a rate of 2℃ / min → allow to cool naturally.

[0110] Comparative Example 2:

[0111] A cooling leather and treatment process, comprising the following steps:

[0112] S1: Prepare an appropriate amount of hexagonal boron nitride (h-BN) powder;

[0113] S2: Select polyurethane synthetic leather as the substrate, fix it on the platform, spray gun spacing 10mm from the substrate, vertically scan to activate the surface, oxygen / helium mixture (volume ratio 1:4), power 500W, scanning speed 5mm / s, process 2 times;

[0114] S3: Apply unmodified boron nitride waterborne polyurethane slurry to the substrate surface, with a coating amount of 60 g / m². 2 The coating gap is 50μm, and the slurry is cured in a 100℃ hot air circulating oven for 30 minutes. The slurry preparation includes:

[0115] 75 parts of polypropylene oxide polyol and 25 parts of polypentyl succinate were stirred at 300 rpm for 30 min at 80 °C. Then, 5 parts of unmodified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylolpropionic acid were added sequentially. The mixture was heated to 85 °C and reacted for 2 h. The mixture was then cooled to 50 °C and 4 parts of triethylamine were added for neutralization for 30 min. Then, 50 parts of acetone, 0.4 parts of polyether-modified silicone defoamer, 0.5 parts of polyether-modified silicone dispersant, 1.8 parts of nonionic polyurethane thickener, and 0.25 parts of fluorine-modified acrylate leveling agent were added. The mixture was stirred for 30 min. The acetone was removed by vacuum distillation at 60 °C / 15 kPa to obtain a slurry with a solid content of 45%.

[0116] S4: After the thermally conductive base layer has cured, embossing is performed at a temperature of 165℃, a linear pressure of 0.4MPa, and a roller speed of 2m / min. Immediately after embossing, the material enters a three-stage heat preservation zone: Stage 1: 140℃×5min (air cooling); Stage 2: 120℃×5min (natural cooling); Stage 3: 80℃×5min (room temperature standing).

[0117] S5: With an O2 / Ar volume ratio of 1:1, the power density is 0.8 W / cm³. 2 Plasma cleaning is performed under conditions of 80 Pa vacuum and 60 s processing time, or under irradiation intensity of 400 W / m². 2 Short-term infrared heating is performed under the condition that the heating time is 60 seconds and the surface temperature of the substrate rises to 65°C.

[0118] S6: Spray paraffin microcapsule phase change material onto the activated embossed layer surface at a spraying pressure of 0.3 MPa, a substrate temperature of 35°C, and a coating weight of 25 g / m². 2 Pre-curing with hot air circulation at 35℃ for 4 minutes;

[0119] S7: A fluorocarbon resin topcoat with modified boron nitride. The fluorocarbon resin topcoat is made of perfluorooctyl ethyl acrylate resin (fluorine content 18%), with 1% perfluorooctyltriethoxysilane pretreated modified boron nitride added. The viscosity is adjusted to 15s with isopropanol, and the coating is applied using an automatic spraying machine at a coating amount of 12g / m². 2 Curing is achieved by circulating hot air at 80℃ for 10 minutes until surface dry.

[0120] S8: After the surface layer is cured, a second-stage cooling process is carried out: keep at 120℃ for 30 minutes → cool down to 100℃ at a rate of 2℃ / min → keep at 120℃ for 30 minutes → cool down to 90℃ at a rate of 2℃ / min → let cool naturally.

[0121] Comparative Example 3:

[0122] A cooling leather and treatment process, comprising the following steps:

[0123] S1: Preparation of modified boron nitride, the preparation steps include:

[0124] S11: Plasma cleaning of hexagonal boron nitride (h-BN) powder, oxygen / argon volume ratio 1:2, total flow rate 50 sccm, power 300 W, vacuum degree 100 Pa, treatment time 10 min;

[0125] S12 Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), add dopamine hydrochloride to a concentration of 3 g / L, add 5 g of h-BN powder at a ratio of h-BN:buffer = 1:30 (g / mL), mechanical stirring (200 rpm) at room temperature for 24 h, centrifugation at 8000 rpm x 10 min, then wash with deionized water for 3 times, freeze-drying to obtain polydopamine coated h-BN, coating rate 15%;

[0126] S13 Hyperbranched polyethyleneimine grafting: disperse the polydopamine coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), add HPEI (5% of the mass of h-BN), 80°C oil bath reflux for 3 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, then wash with ethanol for 2 times, freeze-drying to obtain modified boron nitride;

[0127] S2: Select polyurethane synthetic leather as substrate, fix on the platform, spray gun distance from substrate 10 mm, activate the surface by vertical scanning, oxygen / helium mixed gas (volume ratio 1:4), power 500 W, scanning speed 5 mm / s, process 2 times;

[0128] S3: Apply modified boron nitride water-based polyurethane slurry on the surface of the substrate, coating amount 60 g / m 2 , coating gap 50 μm, 100°C hot air circulation oven curing for 30 min, the slurry preparation includes:

[0129] 78 parts of polypropylene oxide polyol and 22 parts of polybutylene succinate are stirred at 80°C at 300 rpm for 30 min, then 2 parts of modified boron nitride, 38 parts of isophorone diisocyanate, 7 parts of dimethylol propionic acid are added in turn, the temperature is raised to 85°C and reacted for 2 h, the temperature is lowered to 50°C, 4 parts of triethylamine is added and neutralized for 30 min, then 50 parts of acetone, 0.4 parts of polyether modified silicone defoamer, 1.8 parts of non-ionic polyurethane thickener, 0.25 parts of fluorine modified acrylate leveling agent are added, stirred for 30 min, remove acetone under reduced pressure at 60°C / 15 kPa to obtain a slurry with a solid content of 45%;

[0130] S4: After the heat-conducting bottom layer is cured, embossing is performed at a temperature of 165°C, a linear pressure of 0.4 MPa, and a roller speed of 2 m / min, and immediately after embossing, a three-stage heat preservation zone is entered: the first stage: 140°C x 5 min (air cooling); the second stage: 120°C x 5 min (natural cooling); and the third stage: 80°C x 5 min (room temperature standing);

[0131] S5: Plasma cleaning is performed under the conditions of an O2 / Ar volume ratio of 1:1, a power density of 0.8 W / cm 2 , a vacuum degree of 80 Pa, and a processing time of 60 s, or short-time infrared heating is performed under the conditions of an irradiation intensity of 400 W / m 2 , a heating time of 60 s, and a substrate surface temperature of 65°C;

[0132] S6: After the embossed layer is activated, a paraffin microcapsule phase change material is sprayed on the surface of the embossed layer, a spraying pressure of 0.3 MPa, a substrate temperature of 35°C, a coating amount of 25 g / m 2 , and 4 min of 35°C hot air circulation pre-curing;

[0133] S7: A fluorocarbon resin top layer of modified boron nitride is covered, the fluorocarbon resin top layer is prepared from a perfluoro-octyl ethyl acrylate resin (fluorine content 18%) and 1% of perfluoro-octyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15 s by isopropyl alcohol, and the coating amount is 12 g / m 2 , and the top layer is cured to a tack-free state at 80°C hot air circulation for 10 min;

[0134] S8: After the top layer is cured, secondary gradient cooling is performed, 120°C heat preservation for 30 min, reduction to 100°C at a rate of 2°C / min, heat preservation for 30 min, reduction to 90°C at a rate of 2°C / min, and natural cooling.

[0135] Comparative Example Four:

[0136] A cooling leather and a processing technology, comprising the following steps:

[0137] S1: Preparation of modified boron nitride, the preparation steps comprising:

[0138] S11: Hexagonal boron nitride (h-BN) powder is subjected to plasma cleaning, an oxygen / argon volume ratio of 1:2, a total flow rate of 50 sccm, a power of 300 W, a vacuum degree of 100 Pa, and a processing time of 10 min;

[0139] S12 Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), add dopamine hydrochloride to a concentration of 3 g / L, add 5 g of h-BN powder at a ratio of h-BN: buffer = 1:30 (g / mL), mechanical stirring (200 rpm) at room temperature for 24 h, centrifuged at 8000 rpm x 10 min, washed with deionized water for 3 times, freeze-dried to obtain polydopamine coated h-BN, coating rate 15%;

[0140] S13 Hyperbranched polyethyleneimine grafting: disperse the polydopamine coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), add HPEI (5% of the mass of h-BN), 80°C oil bath reflux for 3 h, mechanical stirring (300 rpm), centrifuged at 10000 rpm x 15 min, washed with ethanol for 2 times, freeze-dried to obtain modified boron nitride;

[0141] S2: Select polyurethane synthetic leather as substrate, fix on the platform, spray gun distance from substrate 10 mm, activate the surface vertically, oxygen / helium mixed gas (volume ratio 1:4), power 500 W, scanning speed 5 mm / s, process 2 times;

[0142] S3: Apply modified boron nitride water-based polyurethane slurry on the surface of the substrate, coating amount 60 g / m 2 , coating gap 50 μm, 100°C hot air circulation oven curing for 30 min, slurry preparation includes:

[0143] 75 parts of polypropylene oxide polyol and 25 parts of polybutylene succinate are stirred at 80°C at 300 rpm for 30 min, 5 parts of modified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylol propionic acid are added in turn, the temperature is raised to 85°C and reacted for 2 h, the temperature is lowered to 50°C, 4 parts of triethylamine is added and neutralized for 30 min, then 50 parts of acetone, 0.4 parts of polyether modified silicone defoamer, 1.8 parts of non-ionic polyurethane thickener, and 0.25 parts of fluorine modified acrylate leveling agent are added, stirred for 30 min, and the acetone is removed by vacuum distillation at 60°C / 15 kPa to obtain a slurry with a solid content of 45%;

[0144] S4: After curing the heat-conducting bottom layer, embossing is performed at a temperature of 165°C, a line pressure of 0.4 MPa, and a roller speed of 2 m / min, and immediately after embossing, a three-stage heat preservation zone is entered: first stage: 140°C x 5 min (air cooling); second stage: 120°C x 5 min (natural cooling); third stage: 80°C x 5 min (room temperature standing);

[0145] S5: Plasma cleaning is performed under the following conditions: O2 / Ar volume ratio 1:1, power density 0.8 W / cm 2 , vacuum degree 80 Pa, processing time 60 s, or under the following conditions: irradiation intensity 400 W / m2 Short-time infrared heating was performed at a heating time of 60 s and a substrate surface temperature of 65 °C;

[0146] S6: Spraying paraffin microcapsule phase change material on the surface of the embossed layer after activation, spraying pressure 0.3 MPa, substrate temperature 50 °C, coating amount 25 g / m 2 , 45 °C hot air circulation pre-curing for 4 min;

[0147] S7: Covering the fluorocarbon resin top layer of modified boron nitride, the fluorocarbon resin top layer is made of perfluoro octyl ethyl acrylate resin (fluorine content 18%), 1% perfluoro octyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15 s by isopropyl alcohol, and the coating amount is 12 g / m 2 , 80 °C hot air circulation for 10 min to cure to tack-free;

[0148] S8: After curing the top layer, secondary gradient cooling is performed, 120 °C for 30 min, then reduced to 100 °C at a rate of 2 °C / min, 30 min, then reduced to 90 °C at a rate of 2 °C / min, and then naturally cooled.

[0149] Comparative Example Five:

[0150] A cooling leather and treatment process, comprising the following steps:

[0151] S1: Preparation of modified boron nitride, the preparation steps comprising:

[0152] S11: Plasma cleaning of hexagonal boron nitride (h-BN) powder, oxygen / argon volume ratio 1:2, total flow rate 50 sccm, power 300 W, vacuum degree 100 Pa, treatment time 10 min;

[0153] S12: Polydopamine coating: Tris-HCL buffer (pH = 9.0, concentration 0.1 M), adding dopamine hydrochloride to a concentration of 3 g / L, adding 5 g of h-BN powder at a ratio of h-BN:buffer = 1:30 (g / mL), room temperature mechanical stirring (200 rpm) for 24 h, centrifugation at 8000 rpm x 10 min, then washing with deionized water for 3 times, freeze-drying to obtain polydopamine coated h-BN, coating rate 15%;

[0154] S13: Hyperbranched polyethyleneimine grafting: dispersing the polydopamine coated h-BN in 200 mL of ethanol (concentration 2.5 wt%), adding HPEI (5% of the mass of h-BN), 80 °C oil bath refluxing for 3 h, mechanical stirring (300 rpm), centrifugation at 10000 rpm x 15 min, then washing with ethanol for 2 times, freeze-drying to obtain modified boron nitride;

[0155] S2: Select polyurethane synthetic leather as substrate, fix on platform, spray gun distance 10mm, vertical scanning active surface, oxygen / helium mixed gas (volume ratio 1:4), power 500W, scanning speed 5mm / s, process 2 times;

[0156] S3: Coating modified boron nitride water-based polyurethane slurry on the surface of the substrate, coating amount 60g / m 2 , coating gap 50μm, 100℃ hot air circulation oven curing 30min, slurry preparation includes:

[0157] 75 parts of polypropylene glycol polyol and 25 parts of polybutylene succinate were stirred at 80℃ for 30min at 300rpm, 5 parts of modified boron nitride, 38 parts of isophorone diisocyanate, and 7 parts of dimethylol propionic acid were added in turn, the temperature was raised to 85℃ and reacted for 2h, the temperature was lowered to 50℃, 4 parts of triethylamine was added and neutralized for 30min, then 50 parts of acetone, 0.4 parts of polyether modified silicone defoaming agent, 1.8 parts of non-ionic polyurethane thickener, and 0.25 parts of fluorine modified acrylate leveling agent were added, stirred for 30min, and the acetone was removed by reduced pressure distillation under the condition of 60℃ / 15kPa to obtain a slurry with a solid content of 45%;

[0158] S4: After the heat-conducting bottom layer is cured, embossing is performed at a temperature of 165℃, a linear pressure of 0.4MPa, and a roller speed of 2m / min, and then the embossed layer is directly transferred to a room temperature environment (25℃) for natural cooling at a cooling rate of ≥10℃ / min;

[0159] S5: Plasma cleaning is performed under the conditions of O2 / Ar volume ratio 1:1, power density 0.8W / cm 2 , vacuum degree 80Pa, and processing time 60s, or short-time infrared heating is performed under the conditions of irradiation intensity 400W / m 2 , heating time 60s, and substrate surface temperature rising to 65℃;

[0160] S6: Spraying paraffin microcapsule phase change material on the surface of the embossed layer after activation, spraying pressure 0.3MPa, substrate temperature 35℃, coating amount 25g / m 2 , 35℃ hot air circulation pre-curing 4min;

[0161] S7: Covering a fluorocarbon resin top layer of modified boron nitride, the fluorocarbon resin top layer is prepared from perfluoro octyl ethyl acrylate resin (fluorine content 18%) and 1% perfluoro octyl triethoxysilane pretreated modified boron nitride, the viscosity is adjusted to 15s by isopropyl alcohol, and the coating amount is 12g / m 2 , 80℃ hot air circulation 10min to dry to the touch;

[0162] S8: After the top layer is dry to the touch, it is directly transferred to a room temperature environment (25℃) for natural cooling.

[0163] Table 1 Example and Comparative Example Performance Data Summary

[0164]

[0165] The results in Table 1 show that by Example 1, Example 2 and Example 3, the modified boron nitride content increases from 5% to 8%, the thermal conductivity increases from 1.2 W / (m-K) to 1.5 W / (m-K), showing a significant positive correlation, because as a thermal conductive filler, the increase of the content of modified boron nitride directly improves the density and continuity of the thermal conduction network, and reduces the interface thermal resistance; while in Comparative Example 3, when the content of modified boron nitride decreases to 2%, the thermal conductivity is only 0.9 W / (m-K), which is 25% lower than that of Example 1, which may be due to the insufficient content of the filler causing the thermal conduction path to break, and unable to form an effective heat conduction channel. The results show that the content of modified boron nitride is an important indicator of thermal performance, which needs to be strictly controlled within the range of 3-8%.

[0166] After the plasma cleaning step in Example 1, the contact angle is 135°, and the cooling amplitude is 8.5℃, while in Comparative Example 1, the plasma cleaning step is omitted, the contact angle decreases to 110°, and the cooling amplitude is 5.2℃, which is because the plasma cleaning removes the impurities on the surface of h-BN and activates the substrate, improving the adhesion of the polydopamine coating layer; without cleaning, impurities cause interface defects, weakening the bonding force between the thermal conductive bottom layer and the substrate, which shows that plasma cleaning is a key step to ensure the interface bonding strength.

[0167] In Example 1 and Example 4, the paraffin (37℃) and fatty acid (40℃) phase change materials have cooling amplitudes of 8.5℃ and 9.0℃, respectively, while in Comparative Example 4, the paraffin (50℃) phase change material has a cooling amplitude of 7.5℃, which is because when the phase change temperature is higher than the comfortable temperature range of the human body (35-37℃), the phase change material cannot effectively absorb heat within the target temperature range, resulting in a decrease in cooling effect, which shows that the phase change material needs to be selected from varieties with a phase change temperature of 35-45℃ (claim 5) to ensure that it matches the actual application scenario.

[0168] Examples 1 to 4 use three-stage gradient cooling (cooling rate ≤3℃ / min), the leather deformation rate is low (<3%), and the cooling amplitude is stable, while Comparative Example 5 directly cools at room temperature (rate ≥10℃ / min), the thermal conductivity decreases to 1.0 W / (m-K), the cooling amplitude is 8.0℃, and the deformation rate is 15%, the difference is due to the rapid cooling causing internal stress in the embossed layer and the bottom layer due to the difference in thermal expansion coefficient, causing deformation and interface peeling, which shows that the gradient cooling process effectively reduces thermal stress by controlling the cooling rate, which is the key to ensuring the dimensional stability of the leather.

[0169] The modified boron nitride in Example One is coated by polydopamine-HPEI double layer, and the thermal conductivity is 1.2 W / (m·K). The unmodified boron nitride in Comparative Example Two is directly used, and the thermal conductivity is only 0.7 W / (m·K). The reason is that the unmodified h-BN has strong hydrophobicity and is easy to agglomerate in the polyurethane matrix, resulting in uneven dispersion of the filler. After modification, the h-BN surface is grafted with hydrophilic groups, which improves the compatibility with the resin. The results show that the modification process significantly optimizes the dispersion of the filler and is a necessary means to improve the thermal conductivity.

[0170] Table 2 summarizes the differences between the examples and the comparative examples

[0171]

[0172]

[0173] The results show that the content of modified boron nitride (3-8%) and the cooling rate (≤3℃ / min) should be controlled first, as these two factors have the most significant impact on the performance of the cooling leather. Under the premise of ensuring performance, the plasma cleaning time can be shortened or the type of phase change material can be adjusted. In production, the coating rate and dispersion of modified boron nitride should be strictly monitored to avoid performance fluctuations caused by filler agglomeration. The implementation of the example realizes the preparation of high-performance cooling leather by optimizing the content of the filler, the cleaning process, the phase change temperature, and the cooling rate.

[0174] The specific embodiments described herein merely exemplify the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, without deviating from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A process for cooling of leather and treatment, characterized in that, Comprising the following steps: S1: preparation of modified boron nitride, the preparation step comprising: S11: plasma cleaning of hexagonal boron nitride (h-BN) powder; S12: prepare Tris-HCL buffer solution, add dopamine hydrochloride and hexagonal boron nitride powder, stir at room temperature for 24 hours, then centrifugal wash to obtain polydopamine adhesion layer; S13: disperse the polydopamine adhesion layer obtained in step S12 in ethanol solution, add hyperbranched polyethyleneimine (HPEI) equivalent to 5% of the mass of the polydopamine adhesion layer, the polydopamine coating rate is 10-20% of the mass of h-BN, after reflux reaction at 80℃ for 2-4 hours, centrifugal wash to obtain modified boron nitride; S2: select polyurethane synthetic leather as substrate and perform plasma cleaning to remove surface impurities and activate surface; S3: coating the substrate surface with an aqueous polyurethane slurry containing 3-8% modified boron nitride, coating amount 50-70 g / m 2 , 100°C curing to form a thermally conductive bottom layer; S4: after curing the heat-conducting bottom layer, embossing is performed at 160-170℃, followed by gradient cooling, sequentially through three temperature holding zones of 130-150℃, 110-130℃, 70-90℃, and then to room temperature; S5: plasma cleaning or short-time infrared heating (60-80℃) is performed on the embossed layer to activate the surface hydroxyl groups and enhance the binding force with the phase change material; S6: Spray microcapsule phase change material on the surface of the embossed layer after activation, coating amount 20-30 g / m 2 Pre-cure at 30-40℃ for 3-5 minutes; S7: Covering with a fluorocarbon resin topcoat containing 1-3% modified boron nitride, coating weight 10-15 g / m 2 Immediately after curing to tack-free state at 80°C, entering the S8 cooling program; S8: after curing the surface layer, secondary gradient cooling is performed, holding at 120℃ for 30min, then reducing to 100℃ at a rate of ≤3℃ / min, holding for another 30min, then reducing to 90℃ at a rate of ≤3℃ / min and naturally cooling, forming a continuous temperature curve with the gradient cooling process of step S4.

2. A cooling leather and process for treating as claimed in claim 1 wherein, The modified boron nitride aqueous polyurethane slurry in step S3 comprises the following raw materials by weight fraction: polypropylene oxide polyol 70-80 parts, polyneopentylene succinate 20-30 parts, modified boron nitride 3-8 parts, isophorone diisocyanate 35-40 parts, dimethylol propionic acid 6-8 parts, triethylamine 4-5 parts, acetone 40-50 parts, defoaming agent 0.3-0.5 parts, thickening agent 1.5-2.0 parts, leveling agent 0.2-0.3 parts, wherein the defoaming agent is selected from polyether modified silicone defoaming agent or silica composite silicone defoaming agent, the thickening agent is non-ionic polyurethane associated thickening agent, and the leveling agent is fluorine modified acrylate leveling agent.

3. A cooling leather and process as claimed in claim 1, wherein, The plasma cleaning in the step S11 uses oxygen / argon mixed gas, the power is 200-400W, the power density is 0.5-1.0W / cm 2 , the processing time is 5-15 minutes, the vacuum degree is controlled in 50-200Pa, the pH value of the Tris-HCL buffer in the step S12 is 8.5-9.5, the dopamine hydrochloride concentration is 2-4g / L, and the mass / volume ratio of the hexagonal boron nitride powder to the buffer is 1:(20-50).

4. A cooling leather and process of treating as claimed in claim 1 wherein, The embossing process in step S4 uses a metal roller with microstructure grooves, the embossing temperature is 160-170℃, and the pressure is 0.3-0.5MPa.

5. A cooling leather and process of treatment according to claim 2 or 4, characterized in that, The microcapsule phase change material in step S6 is paraffin or fatty acid, the phase change temperature is 35-45℃, the microcapsule particle size is 5-15μm, and the spraying pressure is 0.2-0.4MPa.

6. A cooling leather and process of treating as claimed in claim 2, wherein, The slurry preparation method comprises: S31: first mix polypropylene oxide polyol and polyneopentylene succinate uniformly at 70-80℃; S32: sequentially add modified boron nitride, isophorone diisocyanate and dimethylol propionic acid; S33: heat to 85-90℃ for 2 hours, then cool down, add triethylamine for neutralization, and then add acetone, defoaming agent, thickening agent and leveling agent, stir for 30 minutes, and remove acetone by reduced pressure distillation after the reaction is completed.

7. A cooling leather and process of treating as claimed in claim 2, wherein, The plasma cleaning in step S5 uses mixed gas of oxygen and argon with volume ratio of 1:1-1:3, power density of 0.5-1.2 W / cm 2 , processing time of 30-90 seconds; or the wavelength of the infrared heating is 2.5-3.5 μm, the irradiation intensity is 300-500 W / m 2 , and the heating time is 45-120 seconds.

8. A cooling leather and process of treating as claimed in claim 1 wherein, The fluorocarbon resin surface layer in step S7 contains perfluorooctyl ethyl acrylate, the fluorine content is 15-20wt%, and the modified boron nitride is pretreated by perfluorooctyl triethoxysilane.

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