Radiation refrigeration environment-friendly leather based on PDMS modified resin and preparation method of radiation refrigeration environment-friendly leather

Abstract

The invention provides a preparation method of refrigeration environment-friendly leather based on PDMS modified resin, which comprises the following steps: firstly, selecting biodegradable polylactic acid (PLA) and polydimethylsiloxane (PDMS) as soft segments, modifying the leather through a chemical copolymerization method, and since the PDMS structure contains both inorganic silicon components and organic components, so that the physical properties of the leather are improved; the polyester leather has stability similar to that of an inorganic material and excellent biocompatibility of an organic material, so that the flexibility, the mechanical property and the like of the traditional polyester leather can be greatly improved. Due to the introduction of the PDMS component in the PDMS modified artificial leather, the radiation refrigeration effect can be achieved; the average emissivity of the refrigeration layer in the atmospheric window wave band is larger than 90%, and the emissivity of the refrigeration layer in the solar wave band is lower than 5%. Compared with common leather, the modified refrigeration environment-friendly leather can be averagely cooled by 6 DEG C in the day at the environment temperature of 30 DEG C.

Description

Technical Field

[0001] The present invention relates to the field of leather materials, and in particular to a modified refrigeration environmentally friendly leather based on PDMS modified resin and a preparation method thereof, aiming to solve the problem of high temperature on the leather surface of vehicle decoration leather materials caused by high temperature during the day. Background Art

[0002] In the hot summer weather, the temperature inside the car has repeatedly hit new highs, causing drivers and passengers to face discomfort and fatigue during driving, and even causing spontaneous combustion. Traditional car air-conditioning systems consume a lot of energy during the cooling process, which aggravates the carbon emissions of vehicles. As my country's energy-intensive industries, the automobile industry and the construction industry have become key areas for low-carbon energy transformation. Traditional refrigeration methods such as air-conditioning systems not only consume a lot of energy, but also produce certain greenhouse gases, aggravating the trend of global warming. Passive radiation refrigeration is a new green refrigeration technology that no longer requires energy input and does not produce any pollutants. It can achieve refrigeration below the ambient temperature by relying solely on the optical properties of the material itself. This radiation refrigeration technology has huge application potential. Leather, as the main material for automotive interiors, luggage accessories, clothing, etc., often causes the surface temperature to rise due to weak heat dissipation capacity, especially for automotive leather interiors, ordinary leather cushions under summer sunshine, etc. In order to use radiation refrigeration technology to achieve efficient radiation heat dissipation of leather, it is necessary to optically modify the leather to achieve the cooling effect of the leather and improve the comfort of human contact. The present invention intends to use PDMS modified resin spin coating to form a modified leather with radiation refrigeration effect. The modified leather has a cooling effect without energy consumption and overcomes some disadvantages of inorganic rigid radiation cooling materials and the limitation of the preparation cost of inorganic radiation cooling materials.

[0003] The existing Chinese patent with publication number CN118326622A discloses a dual-mode radiation thermal management type leather nanofabric and its preparation method. The fabric includes a heating layer and a cooling layer that are self-adhesive through a spinning process. The raw materials of the spinning solution of the heating layer include polyurethane, nano-conductive carbon black and a hydrophobic agent; the raw materials of the spinning solution of the cooling layer include polyurethane, nano-alumina particles, and a hydrophilic agent. The preparation method is: the spinning solution of the heating layer is electrospinned on a receiving substrate to obtain a heating layer fiber membrane; the spinning solution of the cooling layer is continued to spin on the obtained heating layer fiber membrane to obtain a dual-mode radiation thermal management type leather nanofabric. The invention provides a breathable dual-mode leather-like nanofabric with an asymmetric wrinkled photonic microstructure and Janus wettability. It is prepared by a one-step method. The resulting fabric has an asymmetric double-sided wrinkled structure and has good softness, breathability, stretchability and other wearing properties.

[0004] The existing Chinese patent with publication number CN114434926A discloses an intelligent refrigeration artificial leather, which includes a surface layer, a heat insulation layer, a refrigeration layer and a base layer arranged in sequence from the outside to the inside; the refrigeration layer and the base layer are doped with micro-nano particles; the mass percentage of micro-nano particles in the base layer is 0.1wt.%-50wt.%, and the mass percentage of micro-nano particles in the refrigeration layer is 0.1wt.%-50wt.%; the average emissivity of the refrigeration layer in the 8-13μm band is greater than 0.7, and the average reflectivity of the refrigeration layer in the sunlight band is greater than 0.8. The intelligent refrigeration artificial leather of this invention, by regulating the internal structure of the leather, has good air permeability, moisture permeability, heat insulation and waterproof properties while achieving excellent intelligent refrigeration performance, and is suitable for cooling the human body, and has a simple preparation process and low cost.

[0005] The inventor believes that the preparation process of the refrigeration environmentally friendly leather or heat management leather in the current technology is relatively complicated, the cost of some processes and materials is high, and the refrigeration effect needs to be improved. For example, the Chinese patent with publication number CN118326622A, its fabric includes a heating layer and a refrigeration layer self-bonded by a spinning process, and the raw materials of the spinning solution of the refrigeration layer include polyurethane, nano-alumina particles, and a hydrophilic agent. The preparation process is complicated, which greatly limits the promotion and application of refrigeration leather in daily life. Summary of the invention

[0006] In view of the defects in the prior art, the object of the present invention is to provide a radiant cooling environmentally friendly leather based on PDMS modified resin and a preparation method thereof.

[0007] The present invention modifies leather by chemical copolymerization. Since the PDMS structure contains both inorganic silicon components and organic components, it has both stability similar to that of inorganic materials and excellent biocompatibility of organic materials, thus greatly improving the flexibility and mechanical properties of traditional polyester leather. In addition, the present invention uses polylactic acid instead of traditional polyols, introduces degradable components into the leather to make the leather have degradable properties, and can recycle waste leather through chemical degradation, thereby protecting the environment.

[0008] The structure of PDMS-modified polylactic acid-based polyurethane resin is shown in the following formula. PDMS and PLA are used as soft segments, and chemical copolymerization modification is adopted to improve the softness, mechanical properties and environmental performance of the modified leather while ensuring the refrigeration effect of PDMS.

[0009]

[0010] The purpose of the present invention can be achieved by the following scheme:

[0011] The present invention provides a modified refrigeration environmentally friendly leather based on PDMS modified resin, which is prepared by the following method:

[0012] S1. Preparation of PDMS modified polylactic acid based polyurethane resin:

[0013] PLA, diisocyanate, PDMS and a catalyst are added to a solvent for reaction, and then a chain extender is added to carry out a chain extension reaction to obtain a PDMS modified resin;

[0014] S2. Preparation of modified refrigeration environmentally friendly leather:

[0015] The PDMS modified resin and the cross-linking agent are mixed and stirred, and the obtained resin solution is spin-coated to form a film after curing, that is, the modified refrigeration environmentally friendly leather.

[0016] The present invention utilizes ring-opening polymerization to prepare polylactic acid, and then prepares a PU block chain extender by a controlled polymerization method, and then PDMS, PLA and the PU block chain extender are reacted to obtain a leather material. The present invention adopts PLA to replace traditional polyols in raw materials to prepare bio-based environmentally friendly leather, giving leather unique degradation properties under specific conditions (strong acid, strong base), and alleviating the pollution problem caused to the environment by the difficulty of degradation and recycling of traditional leather. The present invention uses PDMS to modify polylactic acid-based polyurethane, and introduces PDMS and PLA as soft segments into the polyurethane structure by a chemical copolymerization modification method, and then realizes the preparation of PDMS-modified environmentally friendly PU of different thicknesses by spin coating, and combines the radiation cooling effect of PDMS and the biodegradable performance of PLA to make it an environmentally friendly leather with radiation cooling effect.

[0017] Preferably, in step S1, the diisocyanate is HMDI.

[0018] Preferably, in step S1, the catalyst includes dibutyltin dilaurate.

[0019] Preferably, in step S1, the molar ratio of diisocyanate, PDMS, and PLA is 1.8-2.2: 0.4-0.6: 0.4-0.6, preferably 2: 0.5: 0.5. The molar ratio of diisocyanate, PDMS, PLA, and catalyst is 1.8-2.2: 0.4-0.6: 0.4-0.6: 0.01-0.02, preferably 2: 0.5: 0.5: 0.01.

[0020] Preferably, in step S1, the solvent comprises DMF.

[0021] Preferably, in step S1, the reaction temperature is 75-85°C, and the reaction time is 1-3 hours. The reaction temperature is preferably 80°C, and the reaction time is preferably 2 hours.

[0022] Preferably, in step S1, the chain extender is BDO. The temperature of the chain extension reaction is 75-85°C, and the reaction time is 5-7h. Preferably, the temperature is 80°C and the reaction time is 6h.

[0023] Preferably, in step S1, based on the total weight of the raw materials diisocyanate, PDMS and PLA as 1 part, the amount of the solvent used is 50-100 parts, and the amount of the chain extender used is 2-5 parts.

[0024] Preferably, in step S2, the crosslinking agent is PEG. The mass ratio of the PDMS modified resin to the crosslinking agent is 8-12:1, preferably 10:1.

[0025] Preferably, step S1 is carried out under stirring. Specifically, it can be carried out in a reaction kettle equipped with a mechanical stirrer. During the stirring process, bubbles are avoided as much as possible. The mixed resin solution can be placed in a vacuum chamber to remove bubbles.

[0026] The spin coating is to drop the PDMS modified resin solution on the center of the substrate, then place the substrate on a spin coater, start the spin coater, and rotate the substrate at a high speed to evenly coat the PDMS modified resin on the substrate surface. The spin coating speed and time can be adjusted as needed. Generally, a higher speed can obtain a thinner film. The substrate to be coated is cleaned and impurities are removed to ensure a clean surface.

[0027] Preferably, in step S2, the curing temperature is 60-70°C and the time is 1-5h. The spin-coated PDMS modified resin / substrate structure is placed on a hot table for curing. Usually, it is heated on a hot table at about 60-70 degrees Celsius for several hours to completely cure the PDMS modified resin; if the PDMS modified resin film needs to be peeled off from the substrate, it can be carefully separated using a blade or a specific peeling technique; the PDMS modified resin film can be subsequently processed according to the needs of the refrigeration and environmentally friendly leather function, such as cutting, punching, bonding, etc.

[0028] Preferably, in step S2, the thickness of the cured film is 500-600 microns.

[0029] The main preparation method of the modified refrigeration environmentally friendly leather of the present invention is to introduce PDMS modified resin as a soft segment into the polyurethane structure, and then prepare PDMS modified PU of different thicknesses by spin coating. The thicker the obtained PDMS modified resin film, the better the refrigeration effect of the modified leather, and the thicker the thickness, the more opaque the refrigeration layer. The average emissivity of the modified leather refrigeration layer in the atmospheric window band is greater than 90%, and the emissivity in the solar band is less than 5%. The modified refrigeration environmentally friendly leather can reduce the temperature by an average of 6°C compared with ordinary leather during the day when the ambient temperature is 30°C, and the temperature reduction is close to 10°C compared with 0.5mm polyurethane leather.

[0030] This scheme modifies leather by chemical copolymerization. Since the PDMS structure contains both inorganic silicon components and organic components, it has both similar stability to inorganic materials and excellent biocompatibility of organic materials, thus greatly improving the flexibility and mechanical properties of traditional polyester leather. In addition, the PDMS-modified artificial leather can achieve the effect of radiation cooling due to the introduction of the PDMS component.

[0031] Different from the previously disclosed use of polydimethylsiloxane for the preparation of radiative cooling layers, this technology can achieve the cooling effect of modified leather while improving the leather's softness and mechanical properties, and plays an important role in the development of functional leather preparation technology. In addition, compared with the preparation process of nanoparticle composite coatings, this technology has the advantages of simpler preparation process and lower preparation cost, which can further enhance the practical application value of modified leather.

[0032] The present invention uses PLA as raw material instead of traditional polyol to prepare bio-based environmentally friendly leather, giving the leather unique degradation performance under specific conditions (strong acid, strong alkali), reducing the pollution problem caused by the difficulty of traditional leather degradation and recycling. In addition, aliphatic HMDI is used instead of traditional aromatic isocyanate, which can further improve the yellowing resistance of the material.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The present invention uses an easily prepared PDMS modified resin film as the cooling layer, and its preparation process is simple and low in cost.

[0035] (2) The modified refrigeration environmentally friendly leather prepared by the present invention has an average emissivity of more than 90% in the atmospheric window band and an emissivity of less than 5% in the solar band; the modified refrigeration environmentally friendly leather can reduce the temperature by an average of 6°C compared with ordinary leather during the day when the ambient temperature is 30°C, and can reduce the temperature by nearly 10°C compared with 0.5mm polyurethane leather. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0037] Figure 1 The environmental solar radiation on the day of testing the modified refrigeration environmentally friendly leather (sample 5) prepared in Example 1;

[0038] Figure 2 The ambient temperature on the day of testing the modified refrigeration environmentally friendly leather (Sample 5) prepared in Example 1;

[0039] Figure 3 The ambient humidity on the day of testing the modified refrigeration environmentally friendly leather (Sample 5) prepared in Example 1;

[0040] Figure 4 The test results of different ordinary leathers under sunlight;

[0041] Figure 5 The test results of the modified refrigeration environmentally friendly leather (samples 5-8) with different PDMS modified resin thickness prepared in Example 1 under sunlight;

[0042] Figure 6 The test results of the modified refrigeration environmentally friendly leather (sample 5) with different PDMS modified resin thickness prepared in Example 1 and the environmentally friendly leather with only PDMS polymerization under sunlight;

[0043] Figure 7 The emissivity test result of the 500 μm thick PDMS modified resin film (sample 5) prepared in Example 1;

[0044] Figure 8 This is the infrared image of the PDMS modified polylactic acid-based polyurethane resin prepared in Example 1. DETAILED DESCRIPTION

[0045] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0046] The present invention provides a method for preparing refrigeration and environmentally friendly leather based on PDMS modified resin (PDMS), wherein biodegradable polylactic acid (PLA) and polydimethylsiloxane (PDMS) are first selected as soft segments, and the leather is modified by chemical copolymerization. Since the PDMS structure contains both inorganic silicon components and organic components, it has both stability similar to that of inorganic materials and excellent biocompatibility of organic materials, and thus can greatly improve the flexibility and mechanical properties of traditional polyester leather. Moreover, the PDMS modified artificial leather can play a radiative cooling effect due to the introduction of the PDMS component therein; and wherein the polylactic acid replaces the traditional polyol, and the degradable component is introduced into the leather to make the leather have degradation performance, and the discarded leather can be recycled by chemical degradation, which plays a protective role in the environment. The average emissivity of the cooling layer in the atmospheric window band is greater than 90%, and the emissivity in the solar band is less than 5%; the modified cooling environmentally friendly leather can reduce the temperature by an average of 6°C compared with ordinary leather during the day when the ambient temperature is 30°C; the main preparation method of the modified cooling environmentally friendly leather is to introduce PDMS with a radiation cooling effect into the polyurethane structure by a chemical modification method, and to prepare modified leather of different thicknesses by spin coating. The present invention achieves the radiation cooling effect of the modified cooling environmentally friendly leather by modifying the polylactic acid-based polyurethane resin leather with PDMS, and the low emissivity of the solar band of the PDMS modified resin and the high emissivity of the atmospheric window, thereby improving the comfort, softness and environmental performance of the artificial leather.

[0047] Example 1

[0048] This embodiment prepares a radiation cooling environmentally friendly leather based on PDMS modified polyurethane resin, and the preparation method thereof is as follows:

[0049] (1) Preparation of PDMS modified polylactic acid based polyurethane resin:

[0050] First, diisocyanate (HMDI), PDMS, PLA, and catalyst (dibutyltin dilaurate) were added simultaneously in a reaction kettle equipped with mechanical stirring, and the molar ratio was 2:0.5:0.5:0.01. Based on 1 part of the reactants (total weight of diisocyanate, PDMS, and PLA), 50 parts of DMF were added as a solvent, and the reaction was carried out at 80°C for 2 hours. Then 2 parts of a chain extender (BDO) were added to carry out a chain extension reaction for 6 hours to obtain a PDMS-modified polyurethane polylactic acid resin solution.

[0051] like Figure 8 As shown, infrared characterization shows that at 1100cm -1 The characteristic peaks on the left and right represent Si-O, 1400 and 2950 cm -1 The characteristic peaks on the left and right represent CH, which are derived from the PDMS part. -1The characteristic peak at 3300 cm represents C=O, which comes from the PLA part. -1 The characteristic peak at represents NH, which is derived from the isocyanate part, indicating the successful preparation of PDMS modified polylactic acid-based polyurethane resin.

[0052] (2) Preparation of modified refrigeration environmentally friendly leather film:

[0053] The obtained PDMS modified polyurethane resin solution and crosslinking agent (PEG) are mixed and stirred at a mass ratio of 10:1. During the stirring process, bubbles are avoided as much as possible. The mixed resin solution can be placed in a vacuum chamber to remove bubbles; the substrate to be coated is cleaned and impurities are removed to ensure that the surface is clean; the PDMS modified resin solution is dropped on the center of the substrate, and then the substrate is placed on a spin coater, the spin coater is started, and the substrate is rotated at a high speed so that the PDMS modified resin is evenly coated on the surface of the substrate. The spin coating speed and time can be adjusted as needed. Usually, a higher speed can obtain a thinner film, and films of different thicknesses are prepared respectively; the spin-coated PDMS modified resin / substrate structure is placed on a hot stage for curing. Usually, the PDMS modified resin is completely cured by heating on a hot stage at about 65°C for 2 hours, and the resulting film thickness is 0.5mm (sample 5), 0.1mm (sample 6), 0.3mm (sample 7), and 0.2mm (sample 8).

[0054] If the PDMS modified resin film needs to be peeled off from the substrate, it can be separated carefully using a blade or a specific peeling technique; the PDMS modified resin film can be subsequently processed according to the needs of the refrigeration and environmentally friendly leather function, such as cutting, punching, bonding, etc.

[0055] Comparative Example 1

[0056] This comparative example is basically the same as Example 1, except that the raw material does not contain PDMS, and the molar ratio of diisocyanate, PLA, and catalyst is 2:1:0.01.

[0057] Comparative Example 2

[0058] This comparative example is basically the same as Example 1, except that the raw material does not contain PLA, and the molar ratio of diisocyanate, PDMS, and catalyst is 2:1:0.01.

[0059] The obtained modified refrigeration environmentally friendly leather was tested, and the test method and results are as follows:

[0060] Yellowing resistance test:

[0061] Use a yellowing resistance tester (KJ-2030B) to test it. At 50℃, irradiate with a sunlight bulb (300w) for 24 hours, observe the color change of the selected samples, and use the GB-T250 color change card to rate them (Level 1: The color is basically unchanged, no obvious aging; Level 2: The color changes slightly, but it does not affect the use; Level 3: The color changes significantly, affecting the use; Level 4: The color changes seriously, affecting the use;)

[0062] Wear resistance test:

[0063] Taber abrasion test was used. At room temperature, the PU artificial leather was abraded by a rotating grinding wheel (H18) to test its wear resistance. The evaluation indexes mainly included the amount of abrasion and the surface condition after abrasion.

[0064] Flexibility (bending resistance) test:

[0065] Use the Bally flex test. At room temperature, fold the sample in half and hold both ends to twist and release alternately, and observe the deformation of the sample. Good quality synthetic leather should be able to quickly recover to its original shape without obvious signs of flexing.

[0066] Different samples were tested and the test results are shown in Table 1.

[0067] Sample 1: 500 μm thick polyurethane leather;

[0068] Sample 2: 500 μm thick PVC leather;

[0069] Sample 3: 500 μm thick microfiber leather;

[0070] Sample 4: 500 micron thick eco-leather;

[0071] Sample 5: 0.5 mm thick PDMS-modified polylactic acid-based PU leather (Example 1);

[0072] Sample 6: 0.1 mm thick PDMS-modified polylactic acid-based PU leather (Example 1);

[0073] Sample 7: 0.3 mm thick PDMS-modified polylactic acid-based PU leather (Example 1);

[0074] Sample 8: 0.2 mm thick PDMS-modified polylactic acid-based PU leather (Example 1);

[0075] Sample 9: 0.5 mm thick PDMS modified PU leather (Comparative Example 2);

[0076] Sample 10: 0.5 mm thick PLA-modified PU leather (Comparative Example 1).

[0077] Table 1

[0078]

[0079] like Figure 1 As shown in the figure, it is the environmental solar radiation on the day of the test of the modified refrigeration environmentally friendly leather in Example 1. Since the radiant cooling effect is closely related to the solar radiation and cloud coverage, it is necessary to record the solar radiation of the test environment. When the clouds block the sunlight, the solar radiation is small, and the overall level of solar radiation is 190W / m 2 And with the change of test time, the solar radiation increases slightly.

[0080] like Figure 2 and Figure 3 As shown in the figure, the ambient temperature and humidity on the day of the modified refrigeration environmentally friendly leather test in Example 1. It can be found from the two figures that as the measurement time changes, the ambient temperature rises and the humidity decreases, which is consistent with the objective environmental law at the corresponding test time. The records of ambient temperature and humidity are helpful to further evaluate the radiation cooling effect of the modified refrigeration environmentally friendly leather.

[0081] like Figure 4 As shown, the data of the radiation cooling effect of 4 different common leathers (samples 1-4) are recorded. The 4 different common leathers are 500 micron thick polyurethane leather (sample 1), polyvinyl chloride leather (sample 2), microfiber leather (sample 3) and environmentally friendly leather (sample 4). It can be found that the back temperature of the four common artificial leathers is equivalent to the ambient temperature, or even higher than the ambient temperature, that is, in hot weather, artificial leather will have a heat preservation effect, causing the temperature of the back of the leather to rise, which is very poor for the comfort of leather in direct contact with the human body.

[0082] like Figure 5As shown, the test results of modified refrigeration environmentally friendly leather (samples 5-8) with different PDMS modified resin thicknesses under sunlight. Among them, the thickness of the PDMS modified resin film of sample 5 is 0.5mm, the thickness of the PDMS modified resin film of sample 6 is 0.1mm, the thickness of the PDMS modified resin film of sample 7 is 0.3mm, and the thickness of the PDMS modified resin film of sample 8 is 0.2mm. It can be found that the temperature of the modified refrigeration environmentally friendly leather with different thicknesses of PDMS modified resin film is significantly lower than that of ordinary artificial leather, and the temperature is reduced by an average of 6°C. This shows that the modified refrigeration environmentally friendly leather can significantly reduce the surface temperature and achieve radiation cooling. At the same time, for the radiation cooling effect of the modified refrigeration environmentally friendly leather with different thicknesses of PDMS modified resin film, it can be found that the thicker the PDMS modified resin film, the better its radiation cooling effect. When the thickness of the PDMS modified resin film is 0.5mm, its cooling will be close to 10°C for 0.5mm polyurethane leather, and the temperature of the modified refrigeration environmentally friendly leather with a 0.1mm thick PDMS modified resin film has further dropped by an average of 3°C.

[0083] like Figure 6 As shown in the figure, the test results of 500 micron thick PDMS modified resin film environmentally friendly leather (sample 5) and environmentally friendly leather with only polymerized PDMS (sample 8) under the same sunlight, it can be found that the 500 micron thick PDMS modified resin film environmentally friendly leather has a better cooling effect, and the temperature is 2-5°C lower than that of the environmentally friendly leather with only polymerized PDMS. Therefore, the PDMS environmentally friendly leather with polymerized PLA can further improve the cooling effect.

[0084] like Figure 7 The figure shows the emissivity test result of a 500 micron thick PDMS modified resin film (sample 5). It can be found that its emissivity in the solar radiation band is less than 5%, while its emissivity in the atmospheric window band is close to 90%, which can realize the radiation cooling technology almost perfectly and achieve a zero-energy cooling effect.

[0085] The present invention application mainly provides a radiation cooling environmentally friendly leather based on PDMS modified resin and a preparation method thereof, which is characterized in that the PDMS modified resin is prepared by a chemical copolymerization modification method, and a radiation cooling layer is formed by spin coating; the average emissivity of the cooling layer in the atmospheric window band is greater than 90%, and the emissivity in the solar band is less than 5%; the modified refrigeration environmentally friendly leather can reduce the temperature by an average of 6°C compared with ordinary leather during the day when the ambient temperature is 30°C; the main preparation method of the modified refrigeration environmentally friendly leather is to introduce the PDMS modified resin as a soft segment into a polylactic acid-based polyurethane structure by a chemical copolymerization modification method, and then prepare PDMS modified PU of different thicknesses by spin coating, so that it becomes a PU surface layer with a specific radiation cooling function.

[0086] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0087] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A radiation cooling environmentally friendly leather based on PDMS modified resin, characterized in that: Prepared by the following method: S1. Preparation of PDMS modified polylactic acid based polyurethane resin: PLA, diisocyanate, PDMS and a catalyst are added to a solvent for reaction, and then a chain extender is added to carry out a chain extension reaction to obtain a PDMS modified resin; S2. Preparation of modified refrigeration environmentally friendly leather: The PDMS modified resin and the cross-linking agent are mixed and stirred, and the obtained resin solution is spin-coated to form a film after curing, that is, the modified refrigeration environmentally friendly leather.

2. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, the diisocyanate is HMDI.

3. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, the catalyst includes dibutyltin dilaurate; and / or, the solvent comprises DMF; And / or, the chain extender is BDO.

4. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, the molar ratio of diisocyanate, PDMS, and PLA is 1.8-2.2: 0.4-0.6: 0.4-0.

6.

5. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, the reaction temperature is 75-85°C, and the reaction time is 1-3h.

6. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, the temperature of the chain extension reaction is 75-85° C., and the reaction time is 5-7 h.

7. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S1, based on the total weight of the raw materials diisocyanate, PDMS and PLA as 1 part, the amount of the solvent used is 50-100 parts, and the amount of the chain extender used is 2-5 parts.

8. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S2, the cross-linking agent is PEG.

9. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S2, the curing temperature is 60-70°C and the curing time is 1-5 hours.

10. The radiant cooling environmentally friendly leather according to claim 1, characterized in that: In step S2, the thickness of the cured film is 500-600 microns.

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