An immersive quiet PU leather and a preparation method thereof

Abstract

The application relates to the technical field of artificial leather, in particular to an immersive quiet PU leather and a preparation method thereof. The immersive quiet PU leather comprises a base cloth, one side of the base cloth is bonded with a middle layer through a high-peeling force bonding layer, and the side, away from the base cloth layer, of the middle layer is coated with a water-based finishing layer; the water-based finishing layer comprises the following raw materials in parts by weight: 50-90 parts of a matt surface treatment agent, 10-50 parts of a gloss surface treatment agent, 5-8 parts of a crosslinking agent, 3-6 parts of an anti-wear agent, 0.5-2 parts of a leveling agent, 0.1-0.5 parts of a penetrating agent, 0.1-3 parts of a mutual solvent, 3-10 parts of a noise reduction auxiliary agent and 10-40 parts of water; the penetrating agent is an alkyl glycoside; and the PU leather has the advantages of improved noise reduction performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of artificial leather, in particular to an immersive quiet PU leather and a preparation method thereof. BACKGROUND

[0002] Due to the long production cycle, limited quantity and high price of natural leather, synthetic leather becomes a substitute for natural leather. PU leather, as a high-quality substitute for natural leather, is widely used in people's production and life. The PU leather produced by the traditional method is mainly made of water-based polyurethane resin as raw material, water, acetone or DMF as solvent, and has the characteristics of not easy to burn and good toughness, and is widely used in furniture, outdoor leather, shoes and bags, and car interior decoration.

[0003] With the development of production economy, PU leather for car interior decoration has new requirements. In the past, the main work of automobile NVH was to reduce vibration and noise. With the development of technology, the radiation noise of most sound sources has been reduced. The traditional sound pressure level and 1 / 3 octave evaluation standard cannot reflect people's subjective judgment of noise. Although the sound pressure level of some sounds is high, people feel more pleasant. In this case, the concept of sound quality emerges as the times require. The "sound" in the definition is not a physical process such as pure sound wave, but a hearing perception process of human ear. "Quality" refers to the subjective judgment made by human ear to the sound event perception process. This concept emphasizes the subjectivity of people's judgment of sound characteristics.

[0004] Although the quietness of the car interior has been maximized in the era of fuel roar, with the increasing market share of new energy in the automobile market, the previous "extreme" cannot meet the needs of the era without engine roar. Therefore, car people and consumers need a high-quietness interior covering material that can better meet the needs of the new car era. The PU leather of the prior art cannot meet this requirement well. SUMMARY

[0005] In order to improve the sound reduction and noise reduction performance of PU leather, the application provides an immersive quiet PU leather and a preparation method thereof.

[0006] In a first aspect, the application provides an immersive quiet PU leather, which adopts the following technical scheme:

[0007] An immersive quiet PU leather comprises a base cloth, a middle layer is bonded to one side of the base cloth through a high-peeling force bonding layer, and a water-based finishing layer is coated on the side of the middle layer away from the base cloth layer; the water-based finishing layer comprises the following raw materials in parts by weight: a matt surface treatment agent 50-90 parts, a gloss surface treatment agent 10-50 parts, a crosslinking agent 5-8 parts, a wear-resistant agent 3-6 parts, a leveling agent 0.5-2 parts, a penetrating agent 0.1-0.5 parts, a mutual solvent 0.1-3 parts, a sound reduction and noise reduction aid 3-10 parts, and water 10-40 parts.

[0008] The sound-damping and noise-reducing additive is vermiculite, and the penetrating agent is alkyl polyglycoside.

[0009] By adopting the technical scheme, the vermiculite has a large specific surface area and internal pores, and adding the vermiculite into the water-based finishing layer can play a role in assisting sound-damping and noise-reducing; the alkyl polyglycoside has low surface tension, good solubility in water and strong wetting capacity, and by taking the alkyl polyglycoside as the penetrating agent, the alkyl polyglycoside can be adsorbed on the surface of the sound-damping and noise-reducing additive, promote the mutual penetration between the organic raw material and the inorganic raw material of the water-based finishing layer, make the water-based finishing layer have better integrity, greatly reduce the dynamic friction coefficient of the surface of the PU leather, and thus improve the sound-damping and noise-reducing performance of the PU leather.

[0010] Preferably, the penetrating agent is prepared by esterification reaction of alkyl polyglycoside, hydroxyl silane coupling agent and carboxyl-terminated hyperbranched polyester, and the preparation method is as follows:

[0011] Under a nitrogen atmosphere, DMF is used as a solvent, n-butanol is used as a water-carrying agent, p-toluenesulfonic acid is used as a catalyst, 13-17 parts by weight of carboxyl-terminated hyperbranched polyester and 0.4-0.6 parts by weight of alkyl polyglycoside and 0.2-0.6 parts by weight of hydroxyl silane coupling agent are added, the temperature is raised to 145-155 DEG C, and stirring reaction is performed, and then the solvent is removed to obtain the penetrating agent.

[0012] By adopting the technical scheme, the alkyl polyglycoside has good foaming property, and after being added into the water-based finishing layer, the water-based finishing layer has rich and delicate foam, which is not conducive to the flatness of the surface of the PU leather and is prone to concave, and thus increases the dynamic friction coefficient of the surface of the PU leather. Moreover, the alkyl polyglycoside has strong thickening capacity, and after being added, the dispersion capacity of the alkyl polyglycoside in the system is poor, and the thickening effect of the alkyl polyglycoside is also not conducive to the dispersion of the sound-damping and noise-reducing additive. Therefore, the alkyl polyglycoside is grafted with the hyperbranched polymer, the hyperbranched polymer has very low viscosity and high solubility in water, and after being grafted, the thickening effect of the alkyl polyglycoside is reduced; and then the alkyl polyglycoside is grafted with the silane coupling agent, the organic silicon compound can reduce the foaming of the alkyl polyglycoside, the silane coupling agent can also be coupled with the sound-damping and noise-reducing additive, and the penetration of the alkyl polyglycoside and the sound-damping and noise-reducing additive is promoted; under the multiple effects, the affinity between the sound-damping and noise-reducing additive and the raw materials is greatly improved, the integrity of the water-based finishing layer is better, the dynamic friction coefficient of the PU leather is further reduced, and the sound-damping and noise-reducing effect of the PU leather is improved.

[0013] Preferably, the average molecular weight of the carboxyl-terminated hyperbranched polyester ranges from 1000 to 6400.

[0014] By adopting the technical scheme, the molecular weight of the carboxyl-terminated hyperbranched polyester is a key factor affecting the penetration performance of the penetrating agent, and the molecular weight of the carboxyl-terminated hyperbranched polyester should not be too low or too high, and the technical effect is better within the range.

[0015] As preferred: the hydroxyl silane coupling agent is 3-[bis(2-hydroxyethyl)amino]propane triethoxysilane.

[0016] By adopting the above technical scheme, the molecule contains two hydrogen bonds, which is relatively easy to react with the carboxyl-terminated hyperbranched polyester.

[0017] As preferred: the addition amount of the 3-[bis(2-hydroxyethyl)amino]propane triethoxysilane is 0.4 parts by weight.

[0018] By adopting the above technical scheme, if the silane coupling agent is added too much, the viscosity of the system is easy to increase, which is not conducive to the dispersibility of the penetrating agent and the permeability of the alkyl polyglycoside; if the silane coupling agent is added too little, its coupling effect is weak and the promotion is insufficient.

[0019] As preferred: the addition amount of the penetrating agent is 0.3 parts by weight.

[0020] By adopting the above technical scheme, the penetrating agent that performs the best penetration effect is 0.5 parts by weight, which is a relatively optimal technical effect, but compared with 0.3 parts by weight, the optimization effect is relatively small. Considering the economic cost, the optimal addition amount is 0.3 parts by weight.

[0021] As preferred: the middle layer includes the following raw materials in parts by weight: PU resin 95-100 parts, DMF 55-70 parts, ethyl acetate 15-25 parts, and color paste 7-28 parts.

[0022] As preferred: the high-peeling-force adhesive layer includes the following raw materials in parts by weight: solvent-free adhesive A 95-100 parts, solvent-free adhesive B 100-110 parts, accelerator 0.045-0.1 parts, curing agent 0.3-0.9 parts, leveling agent 0.25-0.55 parts, and flame retardant 35-55 parts.

[0023] In a second aspect, the application provides a preparation method of an immersive quiet PU leather, which adopts the following technical scheme:

[0024] A preparation method of an immersive quiet PU leather, which includes the following steps:

[0025] S1, mixing the raw materials of the middle layer to obtain a middle layer mixture, coating the middle layer mixture on a release paper, heating and drying to obtain a dried layer, and then coating the middle layer mixture on the dried layer and heating and drying to obtain a middle layer;

[0026] S2, mix each raw material of the high-peeling force adhesive layer to obtain a high-peeling force adhesive layer mixture, coat the high-peeling force adhesive layer mixture to the surface of the middle layer, then pre-bake to a semi-dry state, then adhere the high-peeling force adhesive layer mixture to the base cloth, dry, and then separate the release paper, one side of the release paper is a PU texture surface, and the coated high-peeling force adhesive layer mixture forms a high-peeling force adhesive layer;

[0027] S3, mix each raw material of the water-based finishing layer to obtain a water-based finishing layer mixture, roll coat the water-based finishing layer mixture to the PU texture surface, and dry to obtain the immersion type quiet PU leather.

[0028] By adopting the technical scheme, the preparation method of the application does not need special process or modification of equipment, is easy to operate, has low technical requirements for workers, has high product qualification rate, and is suitable for large-scale production.

[0029] In summary, the application has at least one of the following beneficial technical effects:

[0030] 1. The vermiculite has a large specific surface area and internal pores, and adding the vermiculite to the water-based finishing layer can play a role in assisting sound attenuation and noise reduction; the surface tension of the alkyl glycoside is low, the solubility in water is good, and the wetting capacity is strong; by using the alkyl glycoside as a penetrant, the alkyl glycoside can be adsorbed on the surface of the sound attenuation and noise reduction aid, promote the mutual penetration between the organic raw materials and the inorganic raw materials of the water-based finishing layer, make the water-based finishing layer more integral, greatly reduce the dynamic friction coefficient of the surface of the PU leather, and thus improve the sound attenuation and noise reduction performance of the PU leather.

[0031] 2. The longitudinal dynamic friction coefficient of the PU leather prepared by the application is all 0.34 or less, and the transverse dynamic friction coefficient is all 0.35 or less; and through detection, the RPN is all ≤1, which is far lower than the industry standard; it is proved that the sound attenuation and noise reduction performance of the PU leather prepared by the application is excellent, and the application potential is greatly improved. DETAILED DESCRIPTION

[0032] The application will be further described in detail below in combination with specific contents.

[0033] Raw materials

[0034] The raw materials of the application are all commercially available, wherein the type of the matt surface treatment agent is Dongcao E-1011; the type of the gloss surface treatment agent is DX-1030; the type of the crosslinking agent is S8610; the type of the wear-resistant agent is W3351; the type of the leveling agent is KMT-5510; the mutual solvent is silane coupling agent KH550; the sound attenuation and noise reduction aid is vermiculite powder with a particle size of 800 mesh; the type of the PU resin is PU-8202; the color paste is purchased from Guangzhou Moke Chemical Co., Ltd.; the curing agent is dicalcium phosphate; the type of the flame retardant is 6502-1; and the type of the accelerator is TIN-22.

[0035] Preparation Example

[0036] Preparation Example 1

[0037] A penetrating agent is prepared as follows:

[0038] Under a nitrogen atmosphere, 15 g of carboxyl-terminated hyperbranched polyester is added to 200 mL of DMF, 60 mL of n-butanol is added as a water-carrying agent, 0.3 g of p-toluenesulfonic acid is added as a catalyst, then 0.5 g of alkyl glycoside and 0.4 g of 3-[bis(2-hydroxyethyl)amino]propane triethoxysilane are added, the temperature is raised to 150°C, and stirring is carried out for 15 h, after which the solvent is removed by distillation under reduced pressure to obtain the penetrating agent; wherein the average molecular weight of the carboxyl-terminated hyperbranched polyester is 2600, and the corresponding model number is HyPer C102; the alkyl glycoside is APG0810.

[0039] Preparation Example 2

[0040] A penetrating agent differs from the penetrating agent of Preparation Example 1 in that the average molecular weight of the carboxyl-terminated hyperbranched polyester thereof is 1000, and the corresponding model number is HyPer C101, and the remaining steps are the same as those of Preparation Example 1.

[0041] Preparation Example 3

[0042] A penetrating agent differs from the penetrating agent of Preparation Example 1 in that the average molecular weight of the carboxyl-terminated hyperbranched polyester thereof is 6400, and the corresponding model number is HyPer C103, and the remaining steps are the same as those of Preparation Example 1.

[0043] Preparation Example 4

[0044] A penetrating agent differs from the penetrating agent of Preparation Example 1 in that the amount of 3-[bis(2-hydroxyethyl)amino]propane triethoxysilane added thereto is 0.1 g, and the remaining steps are the same as those of Preparation Example 1.

[0045] Preparation Example 5

[0046] A penetrating agent differs from the penetrating agent of Preparation Example 1 in that the amount of 3-[bis(2-hydroxyethyl)amino]propane triethoxysilane added thereto is 0.6 g, and the remaining steps are the same as those of Preparation Example 1.

[0047] Example

[0048] Example 1

[0049] An immersive quiet PU leather includes a base cloth layer, the middle layer is bonded to one side of the base cloth layer through a high-peeling force bonding layer, and the middle layer is coated with a water-based finishing layer away from the base cloth layer; the raw materials and the amounts of the raw materials of each layer of the PU leather are shown in Table 1, and the specific preparation method of the PU leather is as follows:

[0050] S1, according to the raw material addition amount in Table 1, DMF, ethyl acetate, color paste were added in PU resin to obtain a middle layer mixture, and a release paper was taken; after uniform stirring, the middle layer mixture was coated on the release paper, the coating thickness was 0.20±0.01mm, the vehicle speed was controlled at 10±1m / min, and heating and drying were performed, the oven temperature was increased in steps, and the temperature was 70, 80, 100, 110, 125, 125°C in turn, the total drying time was 4min, and a dried layer was obtained;

[0051] The middle layer mixture was coated on the dried layer again, the coating thickness was 0.25±0.01mm, the vehicle speed was controlled at 10±1m / min, heating and drying were performed, the oven temperature was increased in steps, and the temperature was 70, 80, 100, 110, 125, 125°C in turn, the total drying time was 4min, and a middle layer was obtained;

[0052] S2, according to the raw material addition amount in Table 1, the high-peeling adhesive layer raw materials were mixed to obtain a high-peeling adhesive layer mixture, the high-peeling adhesive layer mixture was coated on the surface of the middle layer, the coating thickness was 0.35±0.01mm, and the vehicle speed was controlled at 10±1m / min; the high-peeling adhesive layer mixture was pre-dried to a semi-dry state, the semi-dry temperature was increased in steps, and the temperature was 100, 100, 100, 110, 125, 125°C in turn; then it was laminated with the base cloth, dried, and the oven temperature was increased in steps, and the temperature was 135, 135, 135, 140, 140, 140, 140, 140, 145, 145, 145, 145, 145, 145°C in turn, the total drying time was 12min, then the release paper was separated, one side of the release paper was a PU texture surface, and the coated high-peeling adhesive layer mixture formed a high-peeling adhesive layer;

[0053] S3, according to the raw material addition amount in Table 1, the water-based finishing layer raw materials were mixed to obtain a water-based finishing layer mixture, a roll coater was used to roll coat the PU texture surface, the vehicle speed was controlled at 9±2m / min, and drying was performed, the drying temperature was 125, 130, 130, 130, 130, 130°C in turn, the drying time was 4min, and after drying, it was rolled to obtain a submerged quiet PU leather;

[0054] In the water-based finishing layer, the penetrating agent was alkyl glycoside APG0810; the solvent-free adhesive A was a mixture of 60kg of polyhexanediol adipate diol, 7kg of 1,4-butanediol, and 33kg of diphenylmethane diisocyanate; the solvent-free adhesive B was stannous octoate.

[0055] Table 1: Raw materials and amounts of each raw material (kg) of Example 1

[0056]

[0057]

[0058] Example 2

[0059] An immersive quiet PU leather, which differs from Example 1 in that the penetrating agent comes from Preparation Example 1, and the remaining steps are the same as Example 1.

[0060] Example 3

[0061] An immersive quiet PU leather, which differs from Example 1 in that the penetrating agent comes from Preparation Example 2, and the remaining steps are the same as Example 1.

[0062] Example 4

[0063] An immersive quiet PU leather, which differs from Example 1 in that the penetrating agent comes from Preparation Example 3, and the remaining steps are the same as Example 1.

[0064] Example 5

[0065] An immersive quiet PU leather, which differs from Example 1 in that the penetrating agent comes from Preparation Example 4, and the remaining steps are the same as Example 1.

[0066] Example 6

[0067] An immersive quiet PU leather, which differs from Example 1 in that the penetrating agent comes from Preparation Example 5, and the remaining steps are the same as Example 1.

[0068] Example 7

[0069] An immersive quiet PU leather, which differs from Example 2 in that the amount of penetrating agent added is 0.1 kg, and the remaining steps are the same as Example 2.

[0070] Example 8

[0071] An immersive quiet PU leather, which differs from Example 2 in that the amount of penetrating agent added is 0.5 kg, and the remaining steps are the same as Example 2.

[0072] Comparative Example

[0073] Comparative Example 1

[0074] An immersive quiet PU leather, which differs from Example 2 in that no penetrating agent is added in the water-based finishing layer, and the remaining steps are the same as Example 2.

[0075] Performance detection test

[0076] Detection method / test method

[0077] The immersion type quiet PU leather was prepared according to the preparation method of examples 1-8 and comparative example 1, and then detected according to the following detection method, and the detection results are shown in table 2.

[0078] RPN: detected according to the detection method in VDA 230-206-2005, RPN is a description of the stick-slip tendency, which describes the tendency of the material to stick-slip under given conditions. For the treatment of material pairs, the smaller the RPN, the better the noise reduction effect of the sound-absorbing material, and RPN greater than 6 means that audible noise can be expected; for the industry standard of sound-absorbing PU leather, RPN≤3.

[0079] Dynamic friction coefficient: the lower the dynamic friction coefficient, the less likely to produce noise, and the detection method is referred to the invention patent with application number 201810791678.4.

[0080] Table 2 detection results of examples 1-8 and comparative example 1

[0081]

[0082] From the detection data of examples 1-8 and comparative example 1 and table 2, it can be seen that the longitudinal dynamic friction coefficient of the PU leather prepared in the application is 0.34 or less, and the transverse dynamic friction coefficient is 0.35 or less; and through detection, its RPN is all ≤1, far lower than the industry standard; it is proved that the sound-absorbing and noise-reducing performance of the PU leather prepared in the application is excellent, and the application potential is greatly improved.

[0083] The surface tension of alkyl polyglycoside is low, the solubility in water is good, and the wetting ability is strong. By using alkyl polyglycoside as a penetrating agent, it can be adsorbed on the surface of the sound-absorbing and noise-reducing additive, promote the mutual penetration between the water-based finishing layer organic raw material and inorganic raw material, make the integrity of the water-based finishing layer stronger, greatly reduce the dynamic friction coefficient of the surface of the PU leather, and thus improve its sound-absorbing and noise-reducing performance. Through the detection data of example 1 and comparative example 1.

[0084] But based on alkyl glucoside good foaming, its addition to the water-based finishing layer, make water-based finishing layer with rich delicate foam, not conducive to the PU leather surface flat, easy to appear concave, increase its surface dynamic friction coefficient. And the thickening ability of alkyl glucoside is strong, after adding, lead to its dispersion ability in the system is not good, its thickening effect is not conducive to the dispersion of sound damping and noise reduction additives. Based on this, by grafting with hyperbranched polymer, due to the low viscosity of hyperbranched polymer, the solubility in water is also high, after grafting, the thickening effect can be reduced; at the same time, grafting with silane coupling agent, the effect of organosilicon compound can reduce the foaming of alkyl glucoside, and the silane coupling agent can also be coupled with sound damping and noise reduction additives, and the penetration of alkyl glucoside is promoted; under the action of multiple, the affinity between sound damping and noise reduction additives and each raw material is greatly improved, the integrity of water-based finishing layer is stronger, thereby further reducing the dynamic friction coefficient of PU leather and improving the sound damping and noise reduction effect. As can be seen from the detection data of examples 1 and 2.

[0085] As can be seen from the detection data of examples 2-4, the molecular weight of carboxyl-terminated hyperbranched polyester is a key factor affecting the penetration performance of the penetrating agent, and the molecular weight should not be too low or too high, and the effect is better when the molecular weight is 2600. According to examples 5-6, the addition amount of silane coupling agent is preferably in the range of 0.2-0.6 kg, and too much silane coupling agent will increase the viscosity of the system, which is not conducive to the dispersion of the penetrating agent and the penetration of alkyl glucoside; too little silane coupling agent will weaken the coupling effect and promote the effect.

[0086] Based on the penetrating agent in example 2, the penetration effect is optimal, and the optimal technical effect is obtained when the addition amount is 0.5 kg, but compared with the addition amount of 0.3 kg, the optimization effect is smaller. Considering the economic cost, the optimal addition amount is 0.3 kg.

[0087] The specific embodiments are only an explanation of the present application, which is not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. An immersive, tranquil PU leather, characterized in that: It includes a base fabric, one side of which is bonded with a middle layer via a high peel strength adhesive layer, and the side of the middle layer away from the base fabric layer is coated with an aqueous finishing layer; the aqueous finishing layer includes the following raw materials in parts by weight: 50-90 parts of matte surface treatment agent, 10-50 parts of gloss-enhancing surface treatment agent, 5-8 parts of crosslinking agent, 3-6 parts of abrasion-resistant agent, 0.5-2 parts of leveling agent, 0.1-0.5 parts of penetrant, 0.1-3 parts of mutual solvent, 3-10 parts of sound-absorbing and noise-reducing agent, and 10-40 parts of water; The noise reduction and sound absorption agent is vermiculite; The penetrant is prepared by esterification of alkyl glycosides, hydroxysilane coupling agents, and carboxyl-terminated hyperbranched polyesters, and the preparation method is as follows: Under a nitrogen atmosphere, using DMF as a solvent, n-butanol as a dehydrating agent, and p-toluenesulfonic acid as a catalyst, 13-17 parts by weight of terminal carboxyl hyperbranched polyester, 0.4-0.6 parts by weight of alkyl glycoside, and 0.2-0.6 parts by weight of hydroxysilane coupling agent are added. The mixture is heated to 145-155℃, stirred, and the solvent is removed to obtain a penetrant. The average molecular weight of the end-carboxyl hyperbranched polyester ranges from 1000 to 6400.

2. The immersive, tranquil PU leather according to claim 1, characterized in that: The hydroxysilane coupling agent is 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane.

3. The immersive, tranquil PU leather according to claim 2, characterized in that: The amount of 3-[bis(2-hydroxyethyl)amino]propanetriethoxysilane added is 0.4 parts by weight.

4. The immersive tranquil PU leather according to claim 1, characterized in that: The amount of the penetrant added is 0.3 parts by weight.

5. The immersive tranquil PU leather according to claim 1, characterized in that: The middle layer comprises the following raw materials in parts by weight: 95-100 parts of PU resin, 55-70 parts of DMF, 15-25 parts of ethyl acetate, and 7-28 parts of color paste.

6. The immersive tranquil PU leather according to claim 1, characterized in that: The high peel strength adhesive layer comprises the following raw materials in parts by weight: 95-100 parts of solvent-free adhesive A, 100-110 parts of solvent-free adhesive B, 0.045-0.1 parts of accelerator, 0.3-0.9 parts of curing agent, 0.25-0.55 parts of leveling agent, and 35-55 parts of flame retardant.

7. A method for preparing the immersive quiet PU leather according to any one of claims 1-6, characterized in that: It includes the following steps: S1. Mix the raw materials of the middle layer to obtain the middle layer mixture, coat the middle layer mixture onto the release paper, heat and dry to obtain the dried layer; coat the middle layer mixture onto the dried layer again, heat and dry to obtain the middle layer; S2. Mix the raw materials of the high peel strength adhesive layer to obtain the high peel strength adhesive layer mixture. Apply the high peel strength adhesive layer mixture to the surface of the middle layer, and then pre-bake it to a semi-dry state. Then, bond it to the base fabric, dry it, and then separate the release paper. One side of the release paper is the PU textured side. The applied high peel strength adhesive layer mixture forms the high peel strength adhesive layer. S3. Mix the raw materials of the water-based coating layer to obtain the water-based coating layer mixture, roll it onto the PU textured surface, and dry it to obtain the immersive tranquil PU leather.

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