Bio-based shoe lining polyurethane synthetic leather as well as preparation method and application thereof

Abstract

The invention discloses bio-based shoe lining polyurethane synthetic leather as well as a preparation method and application thereof, and belongs to the technical field of polyurethane. The bio-based shoe lining polyurethane synthetic leather comprises a wet base layer, a breathable polyurethane layer and a wear-resistant polyurethane layer which are arranged in sequence, wherein the wet base layer is obtained by infiltrating and permeating the base cloth with wet base slurry, and the wet base slurry is prepared by mixing 100 parts by weight of bio-based polyurethane resin SW-6050Bio, 90-120 parts by weight of DMF (Dimethyl Formamide), 10-20 parts by weight of wood powder, 2-10 parts by weight of color paste and 0.2-1 part by weight of a penetrant; and the base cloth is bio-based base cloth. By optimizing the formula of each functional layer, the bio-based shoe lining polyurethane synthetic leather which is high in bio-based content, excellent in air permeability and wear resistance and soft in hand feeling is obtained, and the bio-based shoe lining polyurethane synthetic leather is very suitable for high-grade shoe lining leather products.

Description

Technical Field

[0001] This application belongs to the field of polyurethane synthetic leather technology, specifically relating to a bio-based polyurethane synthetic leather for shoe lining, its preparation method, and its application. Background Technology

[0002] Polyurethane synthetic leather for shoe lining is a type of artificial leather material specifically used for the inner lining of shoes. It is made by coating a base fabric with polyurethane resin, which can simulate the texture and performance of genuine leather.

[0003] Currently, the main raw materials for mainstream polyurethane synthetic leather in the industry are synthesized from the decomposition products of non-renewable traditional fossil materials, such as petroleum and coal. With the increasing tension in the international energy and environmental situation, the replacement of traditional fossil materials has become inevitable. As one of the most basic materials for footwear, the polyurethane synthetic leather currently available on the market has abrasion resistance, flexural strength, tear resistance, and breathability that are highly compatible with the service environment of footwear. However, the raw materials currently used are all derived from traditional petroleum-based materials, which conflicts with the current and future environmental protection situation and the concept of recycling.

[0004] In contrast, while bio-based materials possess advantages such as renewability, biodegradability, and low carbon footprint, their inherent defects, including high polarity, insufficient molecular chain rigidity, and wide molecular weight distribution, result in significant gaps compared to petroleum-based materials in key indicators such as strength, modulus, toughness, heat resistance, and hydrolysis resistance. Currently, bio-based polyurethane synthetic materials in the industry suffer from poor penetration and wetting effects, poor aging resistance, stiff feel, and low tear resistance. When applied to shoe linings, they exhibit insufficient moisture permeability, decreased tear strength, low heat distortion temperature, and susceptibility to hydrolysis and aging after long-term wear, thus greatly hindering the application of bio-based materials in polyurethane synthetic leather for shoe linings. Summary of the Invention

[0005] In view of this, the primary objective of this application is to provide a bio-based polyurethane synthetic leather for shoe linings. By optimizing the formulation of each functional layer, a bio-based polyurethane synthetic leather for shoe linings with high bio-based content, excellent breathability, abrasion resistance, and soft feel is obtained, which is very suitable for high-end shoe lining products.

[0006] To achieve the above objectives, this application adopts the following technical solution: One aspect of this application discloses a bio-based shoe lining polyurethane synthetic leather, which includes a wet-process base layer, a breathable polyurethane layer and an abrasion-resistant polyurethane layer arranged sequentially. The wet-process base layer is obtained by impregnating and permeating the base fabric with a wet-process base slurry. The wet-process base slurry is made by mixing 100 parts of bio-based polyurethane resin SW-6050Bio, 90-120 parts of DMF, 10-20 parts of wood powder, 2-10 parts of color paste and 0.2-1 parts of penetrant according to the weight ratio. The base fabric is a bio-based base fabric.

[0007] Another aspect of this application discloses a method for preparing the bio-based polyurethane synthetic leather for shoe linings described in this application, comprising the following steps: The wet base slurry is coated onto the surface of the base fabric, and the base fabric is impregnated and penetrated. After the wet base slurry completely covers the base fabric, the wet base layer is obtained by coagulation, washing, rolling, drying, cooling and rolling in sequence. A wear-resistant polyurethane slurry is coated onto the surface of release paper, dried and cured to obtain a wear-resistant polyurethane layer; A breathable polyurethane slurry is coated onto the surface of the wear-resistant polyurethane layer, baked until semi-dry, and then bonded to the wet-process base layer. After drying, cooling, and peeling off the release paper, the finished product is obtained.

[0008] The beneficial effects of this application are: The bio-based polyurethane synthetic leather for shoe lining provided in this application comprises a wet-laid base layer, a breathable polyurethane layer, and an abrasion-resistant polyurethane layer. Specifically, this application selects bio-based polyurethane resin SW-6050Bio to formulate the wet-laid base slurry, achieving thorough impregnation of the bio-based base fabric. Utilizing the advantages of SW-6050Bio—soft hand feel, high bio-based content, suitability for penetration and impregnation processes, and ease of production—this application imparts a soft hand feel and excellent moisture permeability to the leather surface. Simultaneously, this application uses ST-2180 abrasion-resistant polyurethane slurry to construct the abrasion-resistant polyurethane layer. ST-2180 has a high hard segment content, exhibiting excellent abrasion resistance, and it can achieve a tight bond with the breathable polyurethane layer and the wet-laid base layer, thus achieving multiple performance indicators including abrasion resistance, tear resistance, and breathability.

[0009] In summary, this application, through the combination of bio-based PU, a breathable polyurethane layer, and abrasion-resistant polyurethane layer, obtains a polyurethane synthetic leather with excellent breathability and moisture permeability and a soft feel, and this polyurethane synthetic leather has a high bio-content. Testing has shown that its bio-based shoe lining polyurethane synthetic leather has an aging resistance of over 3 years and a tear strength higher than 1.5 kg, making it suitable for high-end shoe lining products. Detailed Implementation

[0010] The embodiments of this application will be clearly and completely described below. The technical solutions in the embodiments described below are exemplary and only possible technical implementations of this application, not all possible implementations. Those skilled in the art can combine the embodiments of this application to obtain other embodiments without creative effort, and these embodiments are also within the protection scope of this application.

[0011] The first aspect of this application discloses a bio-based shoe lining polyurethane synthetic leather, which includes a wet-process base layer, a breathable polyurethane layer and an abrasion-resistant polyurethane layer arranged sequentially. The wet-process base layer is obtained by impregnating and permeating the base fabric with a wet-process base slurry. The wet-process base slurry is made by mixing 100 parts of bio-based polyurethane resin SW-6050Bio, 90-120 parts of DMF, 10-20 parts of wood powder, 2-10 parts of color paste and 0.2-1 parts of penetrant according to the weight ratio. The base fabric is a bio-based base fabric.

[0012] In this application, the breathable polyurethane layer is prepared from a breathable polyurethane slurry, which is made by mixing 100 parts of bio-based polyurethane resin, 1-3 parts of breathable agent, and 1-3 parts of color paste in parts by weight.

[0013] In this application, the wear-resistant polyurethane layer is prepared by a wear-resistant polyurethane slurry, which is made by mixing 100 parts of wear-resistant polyurethane resin ST-2180, 40-60 parts of DMF and 1-10 parts of color paste in parts by weight.

[0014] In this application, SW-6050Bio is selected as the bio-based polyurethane resin in the wet-process base slurry. Its excellent hand feel and penetration effect not only enhance the penetration and wetting effect of the wet-process base slurry on the bio-based base fabric, but also form a whole with the bio-based base fabric, giving the synthetic leather a soft hand feel and excellent moisture permeability. Meanwhile, in this application, ST-2180 abrasion-resistant polyurethane resin is selected for the abrasion layer. It not only provides excellent abrasion resistance, but also bonds firmly with the wet-process base layer and the breathable layer, giving the polyurethane synthetic leather excellent tear resistance and breathability.

[0015] In this application, there are no special restrictions on the type of bio-based fabric, but non-woven fabric is preferred.

[0016] The second aspect of this application discloses a method for preparing the bio-based polyurethane synthetic leather for shoe linings as described in the first aspect of this application, comprising the following steps: The wet base slurry is coated onto the surface of the base fabric, and the base fabric is impregnated and penetrated. After the wet base slurry completely covers the base fabric, the wet base layer is obtained by coagulation, washing, rolling, drying, cooling and rolling in sequence. A wear-resistant polyurethane slurry is coated onto the surface of release paper, dried and cured to obtain a wear-resistant polyurethane layer; A breathable polyurethane slurry is coated onto the surface of the wear-resistant polyurethane layer, baked until semi-dry, and then bonded to the wet-process base layer. After drying, cooling, and peeling off the release paper, the finished product is obtained.

[0017] Specific process conditions and parameters can be designed or determined experimentally by those skilled in the art as needed, without particular limitation. In some specific examples, the coating gap of the wet-process base slurry is 1.4-1.5 mm. The coagulation is achieved by completely encapsulating the substrate with the wet-process base slurry in an aqueous solution with a DMF mass fraction of 20%-25%. In the step of preparing the wet-process base layer, the drying temperature is 140-160℃. In the step of preparing the wear-resistant polyurethane layer, the coating gap is 0-10 mils, and the drying temperature is 100-120℃. In the step of obtaining the finished product, the coating gap of the breathable polyurethane slurry is 0.15-0.20 mm, and it is dried to semi-dry at 80-100℃; after being bonded to the wet-process base layer, it is dried at 120-240℃.

[0018] The present application will be further illustrated below with reference to specific embodiments. It should be noted that the specific embodiments below are for illustrative purposes only and do not limit the scope of the present application in any way.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0020] In addition, unless otherwise specified, methods without detailed conditions or steps are conventional methods, and the reagents and materials used are commercially available.

[0021] Information on the main raw materials used in the following examples and comparative examples: Bio-based PU resin, SW-6050Bio, Hefei Anli Polyurethane New Material Co., Ltd., with a bio-based content of 60%.

[0022] Bio-based PU resin, SA-7022Bio, Hefei Anli Polyurethane New Materials Co., Ltd., with a bio-based content of 50%.

[0023] Wear-resistant layer PU resin, ST-2180, Hefei Anli Polyurethane New Material Co., Ltd., bio-based content 0.

[0024] Wear-resistant layer PU resin, ST-8060, Hefei Anli Polyurethane New Material Co., Ltd., bio-based content 0.

[0025] SA-85, adhesive layer polyurethane resin, Hefei Anli Polyurethane New Material Co., Ltd., bio-based content 0.

[0026] Penetrant, BYK-6798, BYK Chemicals, Germany.

[0027] Breathable agent, T01, Xinlan Chemical.

[0028] NK651 spunlace fabric (100% bio-based content), UD065 spunlace fabric (0% bio-based content), Hangzhou Luxian Nonwoven Co., Ltd.

[0029] Example 1 This embodiment discloses a bio-based polyurethane synthetic leather for shoe linings, the specific preparation of which is as follows: S1. Preparation of bio-based wet semi-finished product base According to the weight proportions, 100 parts of PU resin SW-6050Bio, 15 parts of wood powder, 100 parts of DMF, 2 parts of color paste, and 0.5 parts of penetrant BYK-6798 are mixed to prepare a wet slurry. The wet polyurethane slurry is coated onto the surface of NK651 spunlace fabric with a gap of 1.5 mm. After the slurry penetrates the base fabric, it is placed in an aqueous solution of DMF with a mass fraction of 22% to coagulate. After washing and drying, it is dried at 150℃, cooled, and rolled to obtain the bio-based wet semi-finished base.

[0030] S2, Preparation of wear-resistant layer Weigh out 100 parts ST-2180, 60 parts DMF and 3 parts color paste according to the weight ratio to prepare a wear-resistant layer slurry. Apply the wear-resistant layer slurry onto the release paper without gaps and dry and cure it at 100℃ to obtain the wear-resistant layer.

[0031] S3, Prepare the breathable layer Weigh 100 parts by weight of polyurethane resin SA-85, 2 parts by weight of breathable agent T01 and 3 parts by weight of color paste, mix and stir for 3 hours to prepare breathable slurry. Apply the breathable slurry to the surface of the wear-resistant layer with a gap of 0.15 mm, bake at 80°C until semi-dry, and then bond it with the bio-based wet semi-finished base in step S1. After drying at 120°C, cool and peel off to obtain the finished product.

[0032] Example 2 This embodiment discloses another type of bio-based polyurethane synthetic leather for shoe linings, the specific preparation of which is as follows: S1. Preparation of bio-based wet semi-finished product base According to the weight proportions, 100 parts of PU resin SW-6050Bio, 10 parts of wood powder, 90 parts of DMF, 3 parts of color paste, and 0.2 parts of penetrant BYK-6798 are mixed to prepare a wet slurry. The wet polyurethane slurry is coated on the surface of NK651 spunlace fabric with a gap of 1.4mm. After the slurry penetrates the base fabric, it is placed in an aqueous solution of DMF with a mass fraction of 20% to coagulate. After washing and drying, it is dried at 140℃, cooled, and rolled to obtain the bio-based wet semi-finished base.

[0033] S2, Preparation of wear-resistant layer Weigh out 100 parts ST-2180, 40 parts DMF and 2 parts color paste according to the weight ratio to prepare a wear-resistant layer slurry. Apply the wear-resistant layer slurry onto the release paper without gaps and dry and cure it at 110℃ to obtain the wear-resistant layer.

[0034] S3, Prepare the breathable layer Weigh 100 parts by weight of polyurethane resin SA-85, 1 part of breathable agent T01 and 2 parts of color paste, mix and stir for 3 hours to prepare breathable slurry. Apply the breathable slurry to the surface of the wear-resistant layer with a gap of 0.16 mm, bake at 80°C until semi-dry, and then bond it with the bio-based wet semi-finished base in step S1. After drying at 120°C, cool and peel off to obtain the finished product.

[0035] Example 3 This embodiment discloses another type of bio-based polyurethane synthetic leather for shoe linings, the specific preparation of which is as follows: S1. Preparation of bio-based wet semi-finished product base According to the weight proportions, 100 parts of PU resin SW-6050Bio, 20 parts of wood powder, 120 parts of DMF, 8 parts of color paste, and 1 part of penetrant BYK-6798 are mixed to prepare a wet slurry. The wet polyurethane slurry is coated onto the surface of NK651 spunlace fabric with a gap of 1.5 mm. After the slurry penetrates the base fabric, it is placed in an aqueous solution of DMF with a mass fraction of 25% to coagulate. After washing and drying, it is dried at 160℃, cooled, and rolled to obtain the bio-based wet semi-finished base.

[0036] S2, Preparation of wear-resistant layer Weigh out 100 parts ST-2180, 50 parts DMF and 5 parts color paste according to the weight ratio to prepare a wear-resistant layer slurry. Apply the wear-resistant layer slurry onto the release paper without gaps and dry and cure it at 110℃ to obtain the wear-resistant layer.

[0037] S3, Prepare the breathable layer Weigh 100 parts by weight of polyurethane resin SA-85, 3 parts by weight of breathable agent T01 and 5 parts by weight of color paste, mix and stir for 3 hours to prepare breathable slurry. Apply the breathable slurry to the surface of the wear-resistant layer with a gap of 0.20 mm, bake at 100°C until semi-dry, and then bond it with the bio-based wet semi-finished base in step S1. After drying at 150°C, cool and peel off to obtain the finished product.

[0038] Comparative Example 1 This comparative example discloses another bio-based polyurethane synthetic leather for shoe linings, which adopts the same implementation method as Example 1, except that the bio-based polyurethane resin SW-6050Bio in the wet slurry is replaced with an equal amount of SA-7022Bio. All other process steps and condition parameters are the same as in Example 1.

[0039] The specific preparation method is as follows: S1. Preparation of bio-based wet semi-finished product base Take 100 parts by weight of PU resin SA-7022Bio, 15 parts of wood powder, 100 parts of DMF, 2 parts of color paste, and 0.5 parts of penetrant BYK-6798 and mix them to prepare a wet slurry. Coat the wet polyurethane slurry onto the surface of NK651 spunlace fabric with a gap of 1.4-1.5 mm, then place it in an aqueous solution of DMF with a mass fraction of 22% to coagulate, wash with water, roll dry, dry at 150℃, cool, and roll to obtain the bio-based wet semi-finished base.

[0040] S2, Preparation of wear-resistant layer Weigh out 100 parts ST-2180, 60 parts DMF and 3 parts color paste according to the weight ratio to prepare a wear-resistant layer slurry. Apply the wear-resistant layer slurry onto the release paper without gaps and dry and cure it at 100℃ to obtain the wear-resistant layer.

[0041] S3, Prepare the breathable layer Weigh 100 parts by weight of polyurethane resin SA-85, 2 parts by weight of breathable agent T01 and 3 parts by weight of color paste, mix and stir for 3 hours to prepare breathable slurry. Apply the breathable slurry to the surface of the wear-resistant layer with a gap of 0.15 mm, bake at 80°C until semi-dry, and then bond it with the bio-based wet semi-finished base in step S1. After drying at 120°C, cool and peel off to obtain the finished product.

[0042] Comparative Example 2 This embodiment discloses another bio-based polyurethane synthetic leather for shoe linings, which adopts the same implementation method as in Example 1, except that ST-2180 in the abrasion-resistant polyurethane slurry is replaced with an equal amount of ST-8060. All other process steps and condition parameters are the same as in Example 1.

[0043] The specific preparation method is as follows: S1. Preparation of bio-based wet semi-finished product base According to the weight proportions, 100 parts of PU resin SW-6050Bio, 15 parts of wood powder, 100 parts of DMF, 2 parts of color paste, and 0.5 parts of penetrant BYK-6798 are mixed to prepare a wet slurry. The wet polyurethane slurry is coated onto the surface of NK651 spunlace fabric with a gap of 1.4-1.5 mm. Then, it is placed in an aqueous solution of DMF with a mass fraction of 22% to coagulate. After coagulation, it is washed with water, rolled dry, dried at 150℃, cooled, and rolled to obtain the bio-based wet semi-finished base.

[0044] S2, Preparation of wear-resistant layer Weigh out 100 parts ST-8060, 60 parts DMF and 3 parts color paste according to the weight ratio to prepare a wear-resistant layer slurry. Apply the wear-resistant layer slurry onto the release paper without gaps and dry and cure it at 100℃ to obtain the wear-resistant layer.

[0045] S3, Prepare the breathable layer Weigh 100 parts by weight of polyurethane resin SA-85, 2 parts by weight of breathable agent T01 and 3 parts by weight of color paste, mix and stir for 3 hours to prepare breathable slurry. Apply the breathable slurry to the surface of the wear-resistant layer with a gap of 0.15 mm, bake at 80°C until semi-dry, and then bond it with the bio-based wet semi-finished base in step S1. After drying at 120°C, cool and peel off to obtain the finished product.

[0046] Performance testing The bio-based polyurethane synthetic leather used in Examples 1-3 and Comparative Examples 1-2 was compared with our company's conventional commercially available spunlace fabric shoe lining leather (RHDC60X-0.7) in terms of physical properties, aging resistance, and bio-based content. The results are shown in Table 1: Table 1

[0047] The performance tests in Table 1 were conducted according to the following standards: (1) Hardness: ISO17235-2015; (2) Abrasion resistance: Table abrasion resistance H-18×500G; (3) Air permeability: QB / T5156-2017; (4) Aging resistance: QB / T4671-2014; (5) Tear strength: GB / T8949-2008; (6) Bio-based content: ASTM D6866.

[0048] As can be seen from the test results in Table 1, the shoe lining leather made from the polyurethane synthetic leather of this application has comparable softness, hardness, and abrasion resistance to conventional spunlace shoe lining leather, both of which are quite excellent. However, the shoe lining leather obtained in this application has significantly better breathability and bio-based content than conventional spunlace shoe lining leather. Furthermore, the wet-process base layer and the abrasion-resistant polyurethane layer in this application work together to ensure that the synthetic leather not only has a high bio-based content but also meets the various physical property requirements of shoe lining leather. This indicates that the shoe lining leather made from the polyurethane synthetic leather of this application maintains excellent hand feel and abrasion resistance while also possessing excellent breathability and bio-based content.

[0049] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A bio-based polyurethane synthetic leather for shoe lining, characterized in that, It includes a wet-laid base layer, a breathable polyurethane layer, and a wear-resistant polyurethane layer arranged sequentially; The wet-process base layer is obtained by impregnating and permeating the base fabric with a wet-process base slurry. The wet-process base slurry is made by mixing 100 parts of bio-based polyurethane resin SW-6050Bio, 90-120 parts of DMF, 10-20 parts of wood powder, 2-10 parts of color paste and 0.2-1 parts of penetrant according to the weight ratio. The base fabric is a bio-based base fabric.

2. The bio-based polyurethane synthetic leather for shoe lining as described in claim 1, characterized in that, The base fabric is a non-woven fabric.

3. The bio-based polyurethane synthetic leather for shoe lining as described in claim 1, characterized in that, The breathable polyurethane layer is prepared from a breathable polyurethane slurry, which is made by mixing 100 parts of bio-based polyurethane resin, 1-3 parts of breathable agent, and 1-3 parts of color paste in parts by weight.

4. The bio-based polyurethane synthetic leather for shoe lining as described in claim 1, characterized in that, The wear-resistant polyurethane layer is prepared from wear-resistant polyurethane slurry, which is made by mixing 100 parts of wear-resistant polyurethane resin ST-2180, 40-60 parts of DMF and 1-10 parts of color paste in parts by weight.

5. A method for preparing bio-based polyurethane synthetic leather for shoe linings as described in any one of claims 1-4, characterized in that, Includes the following steps: The wet base slurry is coated onto the surface of the base fabric, and the base fabric is impregnated and penetrated. After the wet base slurry completely covers the base fabric, the wet base layer is obtained by coagulation, washing, rolling, drying, cooling and rolling in sequence. A wear-resistant polyurethane slurry is coated onto the surface of release paper, dried and cured to obtain a wear-resistant polyurethane layer; A breathable polyurethane slurry is coated onto the surface of the wear-resistant polyurethane layer, baked until semi-dry, and then bonded to the wet-process base layer. After drying, cooling, and peeling off the release paper, the finished product is obtained.

6. The preparation method according to claim 5, characterized in that, The coating gap of the wet-process base slurry is 1.4-1.5 mm.

7. The preparation method according to claim 5, characterized in that, The coagulation is achieved by immersing the substrate, which is completely encapsulated by the wet-process base slurry, in an aqueous solution with a DMF mass fraction of 20%-25%.

8. The preparation method according to claim 5, characterized in that, In the step of preparing the wet base layer, the drying temperature is 140-160°C.

9. The preparation method according to claim 5, characterized in that, In the step of preparing the wear-resistant polyurethane layer, the coating gap is 0-10 mils and the drying temperature is 100-120℃.

10. The preparation method according to claim 5, characterized in that, In the process of obtaining the finished product, the coating gap of the breathable polyurethane slurry is 0.15-0.20 mm, and it is dried to semi-dry at 80-100℃; after being bonded with the wet-process base layer, it is dried at 120-240℃.

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