Moisture-absorbing and air-permeable ultrafine fiber synthetic leather

Abstract

The application discloses a moisture-absorbing and air-permeable superfine fiber synthetic leather, and relates to the technical field of synthetic leather, which is obtained by adopting modified sea-island fibers and composite fibers, and through processes of cloth forming, needle punching, shrinkage setting, impregnation, weight reduction, fiber opening, drying and post-treatment; wherein, the modified sea-island fibers are prepared from polyamide 6 and modified ethylene polymers with a mass ratio of 3-8:11; the composite fibers are prepared from PET treated by a chemical nucleating agent, chain-extended PET obtained by mixing dipropylene glycol dimethacrylate with the chain-extended PET to extend the chain and repair, and low-density polyethylene with a mass ratio of 12-16:3-7 through melt spinning; the modified ethylene polymers comprise a polymer resin composed of ethylene and butene, hexene or octene of at least two modified groups, and the modified groups are polyether groups, amino groups, hydroxyl groups, carboxyl groups, amide groups, aldehyde groups, carbonyl groups, sulfonic acid groups, acyl chloride groups or phosphoric acid groups. The application has the effects of impact resistance, oxidation resistance, heat resistance, and effective improvement of air permeability and water absorption.

Description

Technical Field

[0001] The present application relates to the technical field of synthetic leather, and in particular to a moisture-absorbing and breathable microfiber synthetic leather. Background Art

[0002] Given the limited availability of natural leather, the development of high-quality synthetic leather has become a trend. Global production of microfiber synthetic leather has already exceeded 100 million square meters, yet demand continues to outstrip supply. While non-microfiber artificial and synthetic leathers are produced in large quantities, they struggle to meet high consumer demands. With the continuous advancement and improvement of production and application technologies, the gradual decline in production costs, shifting consumer attitudes, and increasing environmental awareness, the production and consumption of microfiber synthetic leather has grown rapidly. It is now widely used in high-end footwear, clothing, furniture, balls, and automotive interiors. According to statistics, over 90% of high-end athletic shoes worldwide are made from microfiber synthetic leather.

[0003] The Chinese patent application document with publication number 201410754335.2 discloses a method for preparing a moisture-absorbing and breathable ultrafine fiber polyurethane synthetic leather, which comprises the following steps: (1) Preparation of ultrafine denier sea island fibers and non-woven fabrics: using polyamide 6 and low-density polyethylene as raw materials to prepare ultrafine denier indefinite island short fibers of equal length, opening and combing the prepared ultrafine denier indefinite island short fibers into a web, and then repeatedly puncturing the fibers up and down with high needle density to prepare a non-woven fabric; after being rolled, the fibers are heat-shrinkaged and shaped at a temperature of 90 to 140°C, a speed of 5 to 8 m / min, a non-woven fabric density of 0.3 to 0.35 g / m2, and a shaping roller gap of The ratio of the thickness of the non-woven fabric to the thickness of the non-woven fabric is 1.1 to 1.5, thereby obtaining an ironed non-woven fabric; (2) wet impregnation: the non-woven fabric obtained in step (1) is impregnated with a polycarbonate polyurethane impregnation liquid, wherein the modulus of the impregnation liquid is 50 to 90 kg / cm2 and the solid content is 12 to 16%, and then the non-woven fabric is squeezed and impregnated by a roller, and the impregnation liquid on both sides of the non-woven fabric is scraped clean with a scraper, and then solidified and foamed with a dimethylformamide aqueous solution with a mass concentration of 15 to 25%, and then washed with water to remove the residual dimethylformamide on the non-woven fabric to obtain a porous elastomeric polycarbonate polyurethane non-woven fabric wet base; (3) toluene reduction and drying; (4) peeling treatment; (5) grinding and dust removal; (6) three-plate, dyeing, embossing, ironing and rubbing.

[0004] However, when the preparation method of the moisture-absorbing and breathable microfiber polyurethane synthetic leather uses polyamide 6 and low-density polyethylene as raw materials to prepare sea island staple fibers, the material properties have certain disadvantages in terms of impact resistance, antioxidant and heat resistance. Therefore, when applied to synthetic leather, there is a problem of insufficient strength and toughness, which needs to be improved. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a moisture-absorbing and breathable microfiber synthetic leather to achieve the purpose of improving impact resistance, oxidation resistance, heat resistance, air permeability and water absorption. The specific scheme is as follows:

[0006] A moisture-absorbing and breathable microfiber synthetic leather is obtained by using modified sea-island fibers and composite fibers, and undergoing processes such as cloth forming, needle punching, shrinkage shaping, impregnation, weight reduction and fiber opening, drying and post-treatment; wherein:

[0007] The modified island fiber is prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 3-8:11;

[0008] The composite fiber is prepared by melt spinning PET treated with a chemical nucleating agent and then mixed with dipropylene glycol dimethacrylate to extend the chain to obtain extended PET and low-density polyethylene in a mass ratio of 12-16:3-7;

[0009] The modified ethylene polymer includes a polymer resin composed of ethylene and butene, hexene or octene with at least two modification groups, and the modification groups are polyether groups, amino groups, hydroxyl groups, carboxyl groups, amide groups, aldehyde groups, carbonyl groups, sulfonic acid groups, acyl chloride groups or phosphoric acid groups.

[0010] Preferably, the modified group accounts for 0.5-12 wt% of the modified ethylene polymer, and the melt index of the modified ethylene polymer is 22-60 g / 10 min.

[0011] Preferably, the modified sea-island fiber and the composite fiber are respectively formed into a web or woven into a composite cloth in a mass ratio of 6-10:15-25, and then the composite sea-island fiber cloth is obtained by shrinking and shaping the cloth through needle punching.

[0012] Preferably, the impregnation is to place the composite island fiber into a polyurethane solution for impregnation treatment, wherein the polyurethane solution has a solid content of 8.6-11.2% and a modulus of 30-85 kg / cm 2 After the processing of the padding machine, the synthetic leather blank to be reduced is obtained after the drying and curing treatment.

[0013] Preferably: the modified ethylene polymer also includes a polymer resin composed of ethylene and butene, hexene or octene with a modified group, and the modified group is a polyether group, amino group, hydroxyl group, carboxyl group, amide group, aldehyde group, carbonyl group, sulfonic acid group, acyl chloride group or phosphoric acid group.

[0014] Preferably, the modified group accounts for 0.5-12 wt% of the modified ethylene polymer, and the melt index of the modified ethylene polymer is 37-60 g / 10 min.

[0015] Preferably, the chemical nucleating agent is talc, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 80-90:9.99-15:0.01-5.

[0016] Preferably, in the modified sea-island fiber, the polyamide 6 is an island phase, and the modified ethylene polymer is a sea phase; the intrinsic viscosity of the PET is 0.80-0.82 dL / g.

[0017] From the above solutions, it can be seen that the present application provides a moisture-absorbing and breathable microfiber synthetic leather, which has the following beneficial effects:

[0018] 1. By modifying the sea-island fiber and composite fiber into cloth, the base step of the moisture-absorbing and breathable microfiber synthetic leather can effectively improve the structural strength, achieve the purpose of anti-oxidation and heat resistance during long-term use, effectively extend the service life, and have effective breathability and water absorption during use;

[0019] 2. When preparing modified island-in-the-sea fibers by reacting a polymer resin formed by ethylene having a modifying group with butene, hexene, or octene and polyamide 6, the polymer resin forms a multi-dimensional network structure during the molding process with polyamide 6, thereby avoiding the phenomenon of island merging or island loss. At the same time, the production cost of the modified island-in-the-sea fibers is effectively controlled, and the problems of poor heat resistance, oxidation resistance, and sunlight aging resistance of polyethylene are solved.

[0020] 3. Treating PET with a chemical nucleating agent to form a chain-breaking structure on the PET, so that when mixed with dipropylene glycol dimethacrylate to form a chain extension reaction, the lipid groups and ether bonds in the dipropylene glycol dimethacrylate are combined with the PET to form a polymer grid structure to improve the structural strength of the moisture-absorbing and breathable microfiber synthetic leather;

[0021] 4. By combining a polymer resin composed of ethylene with one modified group and butene, hexene or octene, and a polymer resin composed of ethylene with at least two modified groups and butene, hexene or octene, the structural strength of the modified sea-island fiber is further improved, and the breakage and cross-linking of the polymer chain are effectively inhibited, thereby effectively improving the heat resistance, oxidation resistance and sunlight aging resistance;

[0022] 5. By reacting a chemical nucleating agent composed of talc, zinc pyrrolidone carboxylate and zinc stearate with PET, a multi-segment broken chain structure is formed on the PET, so that dipropylene glycol dimethacrylate can be introduced into the PET through chain extension, thereby improving the material structural strength of the PET and enabling the composite fiber to adsorb the modified sea-island fiber, thereby improving the overall structural stability of the moisture-absorbing and breathable microfiber synthetic leather. DETAILED DESCRIPTION

[0023] The following will be a clear and complete description of the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0024] It should be noted that in the embodiments of the moisture-absorbing and breathable microfiber synthetic leather of this application, the modified island-in-the-sea fibers are prepared using existing island-in-the-sea preparation processes, such as conjugate composite spinning or co-blending spinning, and the melt-spinning composite fibers are prepared using existing fiber preparation processes, which are not described in detail here. Post-treatment includes oiling and surface rubbing to make the surface of the synthetic leather resemble that of genuine leather, improving its aesthetics and tactile properties.

[0025] The following is a detailed description of the moisture-absorbing and breathable microfiber synthetic leather of the present application.

[0026] A moisture-absorbing and breathable microfiber synthetic leather is obtained by using modified sea-island fibers and composite fibers, and undergoing processes such as cloth forming, needle punching, shrinkage shaping, impregnation, weight reduction and fiber opening, drying and post-treatment; wherein:

[0027] The modified island-in-the-sea fiber is prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 3-8:11. The polyamide 6 is the island phase, the modified ethylene polymer is the sea phase, and the intrinsic viscosity of PET is 0.80-0.82 dL / g.

[0028] It should be noted that the modified ethylene polymer includes a polymer resin composed of ethylene and butene, hexene, or octene, each containing at least two modifying groups, wherein the modifying groups are polyether groups, amino groups, hydroxyl groups, carboxyl groups, amide groups, aldehyde groups, carbonyl groups, sulfonic acid groups, acyl chloride groups, or phosphoric acid groups. Furthermore, in the polymer resin composed of ethylene and butene, hexene, or octene, each containing at least two modifying groups, the modifying groups account for 0.5-12 wt% of the modified ethylene polymer, and the melt index of the modified ethylene polymer is 22-60 g / 10 min.

[0029] To further enhance structural strength and stability, the modified ethylene polymers employed in some embodiments of the present application also include polymer resins comprising ethylene having a single modified group and butene, hexene, or octene. In such polymer resins comprising ethylene having a single modified group and butene, hexene, or octene, the modified group accounts for 0.5-12 wt% of the modified ethylene polymer, and the modified ethylene polymer has a melt index of 37-60 g / 10 min.

[0030] The composite fiber is prepared by melt spinning PET treated with a chemical nucleating agent and then mixed with dipropylene glycol dimethacrylate to extend and repair the chain to obtain extended PET and low-density polyethylene in a mass ratio of 12-16:3-7.

[0031] In the embodiment of the present application, the modified island fiber and the composite fiber are respectively formed into a web or woven into a composite cloth in a mass ratio of 6-10:15-25, and then needle-punched to shrink and shape to obtain a composite island fiber cloth. The impregnation is to arrange the composite island fiber into a polyurethane solution for impregnation treatment. The polyurethane solution has a solid content of 8.6-11.2% and a modulus of 30-85 kg / cm 2 After the processing of the padding machine, the synthetic leather blank to be reduced is obtained after the drying and curing treatment.

[0032] In order to achieve effective chain scission of PET to facilitate mixed chain extension of dipropylene glycol dimethacrylate, the chemical nucleating agent in the embodiment of the present application is talc, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 80-90:9.99-15:0.01-5.

[0033] Example 1

[0034] A moisture-absorbing and breathable microfiber synthetic leather is obtained by using modified sea-island fibers and composite fibers, and undergoing processes such as cloth forming, needle punching, shrinkage shaping, impregnation, weight reduction and fiber opening, drying and post-treatment; wherein:

[0035] The modified island-in-the-sea fibers were prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 3:11. The polyamide 6 was the island phase, the modified ethylene polymer was the sea phase, and the intrinsic viscosity of PET was 0.80 dL / g.

[0036] It should be mentioned that the modified ethylene polymer includes a polymer resin composed of ethylene and octene with three modified groups, and in the polymer resin composed of ethylene and octene containing three modified groups, the polymer resin contains 3wt% of carboxyl groups, 1wt% of hydroxyl groups and 1wt% of phosphate groups, and the melt index of the modified ethylene polymer is 39g / 10min.

[0037] The composite fiber is prepared by melt spinning PET treated with a chemical nucleating agent and then mixed with dipropylene glycol dimethacrylate to extend the chain to obtain extended PET and low-density polyethylene in a mass ratio of 12:3.

[0038] In the examples of this application, the modified island-in-the-sea fibers and the composite fibers are formed into a composite cloth or woven into a cloth at a mass ratio of 6:15, and then needle-punched to shrink and shape the composite island-in-the-sea fiber cloth. The impregnation process involves immersing the composite island-in-the-sea fibers in a polyurethane solution. The polyurethane solution has a solid content of 8.6% and a modulus of 30 kg / cm. 2After the processing of the padding machine, the synthetic leather blank to be reduced is obtained after the drying and curing treatment.

[0039] In order to achieve effective chain scission of PET to facilitate mixed chain extension of dipropylene glycol dimethacrylate, the chemical nucleating agent in the embodiment of the present application is talc, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 80:15:5.

[0040] Example 2

[0041] A moisture-absorbing and breathable microfiber synthetic leather is obtained by using modified sea-island fibers and composite fibers, and undergoing processes such as cloth forming, needle punching, shrinkage shaping, impregnation, weight reduction and fiber opening, drying and post-treatment; wherein:

[0042] The modified island-in-the-sea fibers were prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 5:11. The polyamide 6 was the island phase, the modified ethylene polymer was the sea phase, and the intrinsic viscosity of PET was 0.81 dL / g.

[0043] It should be mentioned that the modified ethylene polymer includes a polymer resin composed of ethylene and hexene with two modified groups, and in the polymer resin composed of ethylene and hexene containing two modified groups, the polymer resin contains 3.5wt% of polyether groups and 2.5wt% of sulfonic acid groups, and the melt index of the modified ethylene polymer is 45g / 10min.

[0044] The composite fiber is prepared by melt spinning PET treated with a chemical nucleating agent and then mixed with dipropylene glycol dimethacrylate to extend the chain to obtain extended PET and low-density polyethylene in a mass ratio of 13:5.

[0045] In the examples of this application, the modified island-in-the-sea fibers and the composite fibers are formed into a composite cloth or woven into a cloth at a mass ratio of 7:21, and then needle-punched to shrink and shape the composite island-in-the-sea fiber cloth. The impregnation process involves immersing the composite island-in-the-sea fibers in a polyurethane solution. The polyurethane solution has a solid content of 9.6% and a modulus of 44 kg / cm. 2 After the processing of the padding machine, the synthetic leather blank to be reduced is obtained after the drying and curing treatment.

[0046] In order to achieve effective chain scission of PET to facilitate mixed chain extension of dipropylene glycol dimethacrylate, the chemical nucleating agent in the embodiment of the present application is talc, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 85:13:2.

[0047] Example 3

[0048] A moisture-absorbing and breathable microfiber synthetic leather is obtained by using modified sea-island fibers and composite fibers, and undergoing processes such as cloth forming, needle punching, shrinkage shaping, impregnation, weight reduction and fiber opening, drying and post-treatment; wherein:

[0049] The modified island-in-the-sea fibers were prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 8:11. The polyamide 6 was the island phase, the modified ethylene polymer was the sea phase, and the intrinsic viscosity of PET was 0.82 dL / g.

[0050] It should be mentioned that the modified ethylene polymer includes a polymer resin composed of ethylene and butene with two modified groups, and in the polymer resin composed of ethylene and butene containing two modified groups, the polymer resin contains 0.5wt% of carbonyl groups and 8wt% of amide groups, and the melt index of the modified ethylene polymer is 43g / 10min.

[0051] The composite fiber is prepared by melt spinning PET treated with a chemical nucleating agent and then mixed with dipropylene glycol dimethacrylate to extend the chain to obtain extended PET and low-density polyethylene in a mass ratio of 16:3.

[0052] In the embodiment of the present application, the modified island fiber and the composite fiber are respectively formed into a web or woven into a composite cloth in a mass ratio of 6-10:15-25, and then needle-punched to shrink and shape to obtain a composite island fiber cloth. The impregnation is to arrange the composite island fiber into a polyurethane solution for impregnation treatment. The polyurethane solution has a solid content of 11.2% and a modulus of 85kg / cm 2 After the processing of the padding machine, the synthetic leather blank to be reduced is obtained after the drying and curing treatment.

[0053] In order to achieve effective chain scission of PET to facilitate mixed chain extension of dipropylene glycol dimethacrylate, the chemical nucleating agent in the embodiment of the present application is talc, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 90:9.99:0.01.

[0054] Example 4

[0055] The difference between Example 4 and Example 1 is that the modified ethylene polymer in Example 4 further comprises a polymer resin composed of ethylene and octene with a single modified group. Furthermore, the polymer resin composed of ethylene and octene with a single modified group contains 7 wt% carboxyl groups and 3 wt% acyl chloride groups. The melt index of the modified ethylene polymer is 56 g / 10 min.

[0056] Example 5

[0057] The difference between Example 5 and Example 2 is that the modified ethylene polymer in Example 5 further comprises a polymer resin composed of ethylene and butene with a single modified group. Furthermore, the polymer resin composed of ethylene and butene with a single modified group contains 1 wt% amino groups and 0.5 wt% sulfonic acid groups. The melt index of the modified ethylene polymer is 47 g / 10 min.

[0058] Comparative Example 1

[0059] The difference between Comparative Example 1 and Example 2 is that ethylene polymer is used instead of modified ethylene polymer in Comparative Example 1.

[0060] Comparative Example 2

[0061] The difference between Comparative Example 2 and Example 2 is that PET is used instead of chain-extended PET in Comparative Example 2.

[0062] Comparative Example 3

[0063] The difference between Comparative Example 3 and Example 2 is that the chemical nucleating agent used in Comparative Example 3 is sodium benzoate.

[0064] Test:

[0065] 1. The tensile load and elongation at break were tested according to GB / T 8949-2008;

[0066] 2. The water absorption was tested according to GB / T 4689.21-2008;

[0067] 3. The air permeability was tested according to QB / T 2799-2006;

[0068] 4. The test results are shown in Table 1 below.

[0069] Table 1: Performance test results of Example 1 to Example 5 and Comparative Example 1 to Comparative Example 3

[0070]

[0071]

[0072] From Table 1 above, based on Example 1 and Example 4, in the modified ethylene polymer composed of a polymer resin composed of ethylene and octene with one modification group and a polymer resin composed of ethylene and octene with three modification groups, the prepared moisture-permeable and breathable microfiber synthetic leather has more excellent water absorption and certain improvement in structural strength; based on Example 2 and Comparative Examples 1, 2 and 3, when using modified ethylene polymer, chain-extended PET and sodium benzoate, all have the effect of improving the water absorption of the prepared moisture-permeable and breathable microfiber synthetic leather, and the multi-dimensional network structure improves the structural strength of the moisture-permeable and breathable microfiber synthetic leather, so that the moisture-permeable and breathable microfiber synthetic leather has the effects of improving impact resistance, oxidation resistance, heat resistance, air permeability and water absorption.

[0073] In summary, the present application provides a hygroscopic and breathable microfiber synthetic leather, which is made by modifying the sea island fiber and the composite fiber to form a cloth, so that the base of the obtained hygroscopic and breathable microfiber synthetic leather has the effect of effectively improving the structural strength, achieving the purpose of anti-oxidation and heat resistance during long-term use, effectively extending the service life, and having effective air permeability and water absorption during use. Among them, in terms of modified ethylene polymers, when a polymer resin formed by ethylene with a modified group and butene, hexene or octene is prepared with polyamide 6 to obtain a modified sea-island fiber, the polymer resin forms a multidimensional network structure during the molding process with polyamide 6, thereby avoiding the phenomenon of island merging or island loss, and at the same time effectively controlling the production cost of the modified sea-island fiber, solving the problem of poor heat resistance, oxidation resistance and sunlight aging resistance of polyethylene; at the same time, by combining a polymer resin composed of ethylene with one modified group and butene, hexene or octene and a polymer resin composed of ethylene with at least two modified groups and butene, hexene or octene, the structural strength of the modified sea-island fiber will be further improved, and the effect of effectively improving the heat resistance, oxidation resistance and sunlight aging resistance will be achieved. In terms of chain extension PET and its chemical nucleating agent, PET is treated with a chemical nucleating agent to form a broken chain structure on PET for providing exchange groups, so that when mixed with dipropylene glycol dimethacrylate to form a chain extension reaction, the lipid groups and ether bonds in the dipropylene glycol dimethacrylate are combined with PET to form a polymer grid structure for improving the structural strength of the moisture-absorbing and breathable ultrafine fiber synthetic leather, so that a chemical nucleating agent composed of talcum powder, zinc pyrrolidone carboxylate and zinc stearate reacts with PET to form a multi-segment broken chain structure on PET, so that dipropylene glycol dimethacrylate can be introduced into PET through chain extension, thereby improving the material structural strength of PET, and making the composite fiber have adsorbed modified sea island fibers, thereby improving the overall structural stability of the moisture-absorbing and breathable ultrafine fiber synthetic leather.

[0074] References to "first," "second," "third," "fourth," and the like (if any) herein are intended to distinguish similar objects and are not necessarily intended to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, e.g., a process, method, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, or apparatus.

[0075] It should be noted that the descriptions of "first", "second", etc. in this application are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0076] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A moisture-absorbing and breathable microfiber synthetic leather, characterized in that: The method comprises adopting modified sea island fiber and composite fiber, and undergoing cloth forming, needle punching, shrinkage setting, impregnation, weight reduction and fiber opening, drying and post-processing to obtain the fiber; wherein: The modified island fiber is prepared from polyamide 6 and modified ethylene polymer in a mass ratio of 3-8:11; The composite fiber is prepared by treating PET with a nucleating agent, mixing it with dipropylene glycol dimethacrylate to extend and repair the chain to obtain extended PET, and then melt-spinning it with low-density polyethylene at a mass ratio of 12-16:3-7; The modified ethylene polymer comprises a first polymer resin composed of ethylene and butene, hexene or octene with at least two first modifying groups, and the first modifying group is a polyether group, an amino group, a hydroxyl group, a carboxyl group, an amide group, an aldehyde group, a carbonyl group, a sulfonic acid group, an acyl chloride group or a phosphoric acid group; The nucleating agent is talc powder, zinc pyrrolidone carboxylate and zinc stearate in a mass ratio of 80-90:9.99-15:0.01-5.

2. The moisture-absorbing and breathable microfiber synthetic leather according to claim 1, characterized in that: The first modifying group accounts for 0.5-12 wt% of the modified ethylene polymer, and the melt index of the modified ethylene polymer is 22-60 g / 10 min.

3. The moisture-absorbing and breathable microfiber synthetic leather according to claim 1, characterized in that: The modified sea-island fiber and the composite fiber are meshed into a composite cloth or woven into a cloth in a mass ratio of 6-10:15-25, and then the composite sea-island fiber cloth is obtained by shrinking and shaping the cloth through needle punching.

4. The moisture-absorbing and breathable microfiber synthetic leather according to claim 3, characterized in that: The impregnation is to place the composite island fiber into a polyurethane solution for impregnation treatment. The solid content of the polyurethane solution is 8.6-11.2%, and the modulus is 30-85kg / cm 2 After the processing of the padder, the synthetic leather blank to be reduced is obtained after drying and curing.

5. The moisture-absorbing and breathable microfiber synthetic leather according to claim 1, characterized in that: The modified ethylene polymer also includes a second polymer resin composed of ethylene and butene, hexene or octene with a second modifying group, and the second modifying group is a polyether group, an amino group, a hydroxyl group, a carboxyl group, an amide group, an aldehyde group, a carbonyl group, a sulfonic acid group, an acyl chloride group or a phosphoric acid group.

6. The moisture-absorbing and breathable microfiber synthetic leather according to claim 5, characterized in that: The mass percentage of the second modifying group in the modified ethylene polymer is 0.5-12 wt%, and the melt index of the modified ethylene polymer is 37-60 g / 10 min.

7. The moisture-absorbing and breathable microfiber synthetic leather according to claim 1, characterized in that: In the modified sea-island fiber, the polyamide 6 is an island phase, and the modified ethylene polymer is a sea phase; the intrinsic viscosity of the PET is 0.80-0.82 dL / g.

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