EP3859078A1

EP3859078A1 - Artificial leather of ethylene-propylene copolymer and manufacturing method thereof

Info

Publication number: EP3859078A1
Application number: EP21153866.5A
Authority: EP
Inventors: Chih-Yi Lin; Kuo-Kuang Cheng; Chi-chin CHIANG; Chi-Wei Chang
Original assignee: San Fang Chemical Industry Co Ltd
Current assignee: San Fang Chemical Industry Co Ltd
Priority date: 2020-01-31
Filing date: 2021-01-27
Publication date: 2021-08-04
Also published as: US20210238798A1; CN113201941A

Abstract

The present disclosure provides an artificial leather including a fabric layer and an ethylene-propylene copolymer (EPM) layer attached to the fabric layer. The EPM layer is an EPM composite layer including an EPM foaming layer and an EPM surface layer. The present disclosure further provides a method for manufacturing the artificial leather, and a shoe structure including the artificial leather.

Description

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to an artificial leather and a manufacturing method, and more particularly to an artificial leather made by environmentally-friendly processes, and a manufacturing method thereof.

2. Description of the Related Art

Conventional artificial leather may be manufactured by a dry process or a wet process. The wet process involves impregnating or coating a textile with a resin solution including resin (e.g., polyurethane), organic solvent (e.g., dimethylformamide), surfactant, colorant, filler, etc. Then, the organic solvent may be replaced by water, so as to form pores in the resin. The resin is then solidified, thus forming the conventional artificial leather. In the dry process, a resin solution is coated on a release material. After it is dried, a paste is applied on the resin, and the resin is attached to a textile. The resin is then matured at a specific temperature, and the release material is removed to obtain the conventional artificial leather. However, both dry and wet processes involve the use of organic solvents such as dimethylformamide. Although these organic solvents can be recycled and reused, the recycling equipment is quite expensive, while the recovery rate may not be high. Moreover, conventional artificial leather cannot meet the requirement of zero detection of organic solvents.
An improvement of the aforementioned processes may include heat press laminating or extrusion laminating polyurethane onto a textile. However, the resultant artificial leather is heavy, and has a stiff hand feel and rubber-like appearance. It is also uncomfortable to wear, and not completely recyclable.

SUMMARY

To address at least some of the aforementioned issues, the present disclosure provides an artificial leather which can be manufactured by environmentally-friendly processes. The artificial leather is light-weight, and provides a favorable hand feel and leather-like appearance. The artificial leather is also comfortable to wear, and is completely recyclable.
The present disclosure provides an artificial leather including a fabric layer and an ethylene-propylene copolymer (EPM) layer attached to the fabric layer. The EPM layer is an EPM composite layer including an EPM foaming layer and an EPM surface layer.
The present disclosure further provides a method for manufacturing the aforementioned artificial leather including: providing the fabric layer; providing the EPM layer; and attaching the EPM layer to the fabric layer.
The present disclosure further provides a shoe structure including the aforementioned artificial leather.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of an artificial leather according to a first embodiment of the present disclosure.
FIG. 2 illustrates a cross-sectional view of an artificial leather according to a second embodiment of the present disclosure.
FIG. 3 illustrates a cross-sectional view of an artificial leather according to a third embodiment of the present disclosure.
FIG. 4 illustrates a cross-sectional view of an artificial leather according to a fourth embodiment of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates a cross-sectional view of an artificial leather 1 according to a first embodiments of the present disclosure. The artificial leather 1 includes a fabric layer 11 and an ethylene-propylene copolymer (EPM) layer 12 attached to the fabric layer 11.
For example, the artificial leather of the present disclosure may be used in clothing, shoes, hats, accessories, furniture, wall decorations, etc., or raw materials or semi-finished products. Alternatively, the artificial leather may be used in handicrafts or for other purposes, which are not limited by the present disclosure. In one embodiment, the artificial leather may be a part of a shoe structure, such as a part of or the entire shoe upper in the shoe structure.
In one embodiment of the present disclosure, the fabric layer may be any type of fabrics, such as woven fabrics or nonwoven fabrics. In one embodiment, the fabric layer is a nonwoven fabric. The term "nonwoven fabric" used in the present disclosure refers to a sheet, web or bat manufactured by directionally or randomly oriented fibers, bonded by friction, and/or cohesion and/or adhesion, excluding paper or products which are woven, knitted, tufted stitch bonded incorporating binding yarns or filaments, or felted by wet milling, whether or not additionally needled. The fibers may be of natural or man-made origin. They may be staple or continuous filaments or may be formed in situ. Depending on the method for forming the web, the nonwoven fabric usually includes a composite nonwoven fabric, a needle-punched nonwoven fabric, a melt-blown nonwoven fabric, a spun bonded nonwoven fabric, a dry-laid nonwoven fabric, a wet-laid nonwoven fabric, a stitch-bonded nonwoven fabric, or a spun lace nonwoven fabric. The fabric layer provides a soft hand feel similar to real leather.
In one embodiment of the disclosure, the fiber layer comprises a plurality of fibers. Preferably, the fibers are made of at least one material selected from the group consisting of polyene, polyamide, poly(p-phenylene terephthalamide), polyolefin, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polytrimethylene terephthalate(PTT), polybutylene terephthalate (PBT), polyacrylonitrile (PAN), and a mixture thereof.
FIG. 2 illustrates a cross-sectional view of an artificial leather 2 according to a second embodiment of the present disclosure. The artificial leather 2 also includes a fabric layer 21 and an EPM layer, while the EPM layer is an EPM composite layer 22. The EPM composite layer 22 includes an EPM foaming layer 221 and an EPM surface layer 222. The fabric layer 21 is attached to the EPM foaming layer 221. The EPM surface layer 222 is disposed on a surface of the EPM foaming layer 221 opposite to the fabric layer 21. That is, the EPM foaming layer 221 has a first surface and a second surface opposite to the first surface. The fabric layer 21 is attached to the first surface of the EPM foaming layer 221, and the EPM surface layer 22 is disposed on the second surface of the EPM foaming layer 221.
In one preferred embodiment of the present disclosure, a manner of foaming the EPM foaming layer may be chemically foaming or physically foaming, wherein the chemically foaming manner uses an agent capable of conducting a chemical reaction to yield gas, with the gas evenly distributed in the EPM. In another aspect, the physically foaming manner includes infiltrating gas or supercritical carbon dioxide into the EPM, and making the gas evenly distributed in the EPM by stirring to form the EPM foaming layer. Since the EPM foaming layer includes foaming pores, it is capable of replacing the polyurethane used in the conventional artificial leather, especially the wet-process polyurethane. The EPM foaming layer can provide a thick and rich hand feel similar to the wet-process polyurethane. In another aspect, since the density of the EPM is less than the density of the polyurethane used in conventional artificial leather, the EPM is lighter in weight at the same thickness. Preferably, the foaming density reduction rate (density after foaming/density before foaming) of the EPM foaming layer is about 40% to about 90%.
In one preferred embodiment of the present disclosure, the EPM foaming layer includes a plurality of independent pores. In another aspect, a diameter of the pores in the EPM foaming layer is about 20 µm to about 150 µm, preferably about 50 µm to about 120 µm, and more preferably about 70 µm to about 100 µm. As such, the EPM foaming layer is capable of providing a thick, rich and bouncy hand feel similar to real leathers.
In one preferred embodiment of the present disclosure, the EPM foaming layer has a thickness of about 0.10 mm to about 0.70 mm, preferably 0.25 mm to about 0.55 mm, and more preferably about 0.30 mm to about 0.40 mm. A hardness of the EPM foaming layer is about 50 A to about 80 A, preferably about 55 A to about 75 A, and more preferably about 60 A to about 70 A. A melting point of the EPM foaming layer is about 60°C to about 200°C, preferably about 100°C to about 190°C, and more preferably about 130°C to about 170°C.
In one preferred embodiment of the present disclosure, the EPM surface layer presents a texture on a surface opposite to the EPM foaming layer. That is, the EPM surface layer has a first surface facing the EPM foaming layer and a second surface opposite to the first surface. The texture is presented on the second surface of the EPM surface layer. A method for forming the texture may include transfer printing using a release material or a mold having a corresponding texture, but is not limited thereto.
In one preferred embodiment of the present disclosure, a thickness of the EPM surface layer is about 0.10 mm to about 0.50 mm, preferably about 0.20 mm to about 0.40 mm, and more preferably 0.30 mm to about 0.35 mm. A hardness of the EPM surface layer is 50 A to about 95 A, preferably about 55 A to about 80 A, and more preferably about 65 A to about 75 A. A melting point of the EPM surface layer is about 60°C to about 200°C, preferably about 100°C to about 190°C, and more preferably about 130°C to about 170°C.
In one preferred embodiment of the present disclosure, a ratio of the thickness of the EPM surface to the thickness of the EPM foaming layer is about 9:1 to about 1:9, preferably about 5:1 to about 1:5, and more preferably about 3:1 to about 1:3.
In one preferred embodiment of the present disclosure, the EPM layer further includes an EPM adhesive layer, and the fabric layer is attached to the EPM layer through the EPM adhesive layer. FIG. 3 illustrates a cross-sectional view of an artificial leather 3 according to a third embodiment of the present disclosure. The artificial leather 3 also includes a fabric layer 31 and an EPM layer, while the EPM layer is an EPM composite layer 32. The EPM composite layer 32 includes an EPM foaming layer 321, an EPM surface layer 322, and an EPM adhesive layer 323. The fabric layer 31 is attached to the EPM layer (e.g., the EPM composite layer 32) through the EPM adhesive layer 323. For example, the fabric layer 31 is attached to the EPM foaming layer 321 by the EPM adhesive layer 323, and the EPM surface layer 322 is disposed on a surface of the EPM foaming layer 321 opposite to the fabric layer 31. That is, the EPM adhesive layer 323 and the EPM surface layer 322 are respectively disposed on two opposite surfaces of the EPM foaming layer 321. Preferably, the EPM adhesive layer 323 is a hot-melt adhesive.
In one preferred embodiment of the present disclosure, a hardness of the EPM adhesive layer is about 50 A to about 85 A, preferably about 55 A to about 80 A, and more preferably about 60 A to about 75 A. A melting point of the EPM adhesive layer is about 50°C to about 140°C, preferably about 55°C to about 130°C, and more preferably about 60°C to about 110°C.
In another preferred embodiment of the present disclosure, the fabric layer is attached to the EPM foaming layer by another adhesive layer. Preferably, the other adhesive layer is a hot-melt adhesive, more preferably a hot-melt adhesive of EPM. That is, the adhesive layer may not be a part of the EPM layer or the EPM composite layer.
In one preferred embodiment of the present disclosure, the artificial leather further includes a covering layer disposed on a surface of the EPM layer opposite to the fabric layer. That is, the EPM layer has a first surface and a second surface opposite to the first surface. The fabric layer is attached to the first surface of the EPM layer, and the covering layer is disposed on the second surface of the EPM layer. FIG. 4 illustrates a cross-sectional view of an artificial leather according to a fourth embodiment of the present disclosure. The artificial leather 4 includes a fabric layer 41, an EPM layer (e.g., an EPM composite layer 42) and a covering layer 43. The EPM composite layer 42 includes an EPM foaming layer 421, an EPM surface 422, and an EPM adhesive layer 423. The fabric layer 41 is attached to the EPM foaming layer 421 by the EPM adhesive layer 423, and the EPM surface layer 422 is disposed on a surface of the EPM foaming layer 421 opposite to the fabric layer 41. The covering layer 43 is disposed on a surface of the EPM surface layer 422 opposite to the EPM foaming layer 421 or the fabric layer 41. In another embodiment of the present disclosure, the EPM composite layer may only include, or be composed of, an EPM foaming layer and an EPM surface layer.
The covering layer of the present disclosure includes, but is not limited to, polyurethane, thermoplastic polyurethane, polyolefin or thermoplastic polyolefin. Preferably, the polyurethane is an aqueous polyurethane. The covering layer may optionally present textures or have microstructures on its surface, or may include pigments.
As described above, the artificial leather of the present disclosure is mainly made of EPM. When the fabric layer made of polyolefin is used, the artificial leather is completely made of polyolefin materials, and thus is completely recyclable. Furthermore, the artificial leather of the present disclosure has leather-like hand feel, and excellent physical properties and abrasion resistance. The torsion resistance strength of the artificial leather can reach 2.5 kgf/cm or more. Compared with natural leather or conventional artificial leather, the artificial leather of the present disclosure is light-weight and soft, and is suitable for all kinds of applications, especially shoes.
The present disclosure further provides a method for manufacturing the aforementioned artificial leather, including: providing the fabric layer; providing the EPM layer; and attaching the EPM layer to the fabric layer.
In one preferred embodiment of the present disclosure, the EPM layer is an EPM composite layer including an EPM foaming layer and an EPM surface layer. The method includes forming the EPM foaming layer and the EMP surface layer concurrently.
In one embodiment of the present disclosure, "forming the EPM foaming layer and the EMP surface layer concurrently" may be achieved by co-extruding the EPM foaming layer and the EPM surface layer. The co-extrusion process includes, but is not limited to, drying the materials of the EPM foaming layer and/or the EPM surface layer; melting the aforementioned materials; co-extruding the materials using a die (e.g., a T-die); and cooling the materials to a predetermined thickness. In one embodiment of the present disclosure, a release material may be applied to a surface of the EPM layer during the co-extrusion process (e.g., before the cooling step), such that the surface texture of the release material can be transfer printed on the EPM surface layer.
In one preferred embodiment of the present disclosure, the EPM composite layer further includes an EPM adhesive layer. Accordingly, the method may include co-extruding the EPM foaming layer, the EPM surface layer and the EPM adhesive layer.
In one preferred embodiment of the present disclosure, the EPM adhesive layer is a hot-melt adhesive. The method includes heat press laminating the EPM adhesive layer to the fabric layer, such that the EPM composite layer is attached to the fabric layer through the EPM adhesive layer.
In one preferred embodiment of the present disclosure, the method includes extrusion laminating the EPM foaming layer to the fabric layer, such that the EMP layer (e.g., the EPM composite layer) is attached to the fabric layer.
In one preferred embodiment of the present disclosure, the method includes attaching the EPM layer to the fabric layer by another adhesive layer. Preferably, the other adhesive layer is a hot-melt adhesive, more preferably a hot-melt adhesive of EPM.
In one preferred embodiment of the present disclosure, the method further includes providing a covering layer, and attaching the covering layer to a surface of the EPM layer opposite to the fabric layer.
The method of the present disclosure can avoid the use of organic solvents in the manufacturing process of the conventional artificial leather. Hence, the method of the present disclosure meets the 2020 ZDHC (Zero Discharge of Hazardous Chemicals) requirements. Furthermore, the method of the present disclosure is simpler and faster than the conventional wet process.
The present disclosure further provides a shoe structure including the aforementioned artificial leather. For example, the artificial leather may be a part of or the entire shoe upper in the shoe structure. That is, the artificial leather a can be combined with the sole and other parts to form the shoe structure.
The following examples are given to illustrate the method for manufacturing the conjugated fiber of the present disclosure, but are not intended to limit the scope of the present invention.

Example 1:

Drying condition: The EPM was dried to a moisture content of about 300 ppm or lower.
Extruder temperature:

EPM surface layer (component A): 170°C, 200°C, 200°C
The temperature of the T-die was set at 185°C.

The EPM surface layer was extrusion laminated to a nonwoven fabric, and was cooled by cooling rollers. The speed of the laminating rollers was set at 3.0 m/min, thus forming an artificial leather of EPM having a thickness of about 0.8 mm.
Then, the artificial leather was pressed by embossing rollers having a surface temperature of 100°C, thus forming the surface-textured artificial leather of EPM.

Example 2:

EPM surface layer (component A): 170°C, 200°C, 200°C
EPM foaming layer (component B): 150°C, 195°C, 190°C, with 1% to 5% microsphere foaming agent added.

The temperature of the T-die was set at 185°C.
The metering pumps of the component A and the component B were set so that the thickness ratio of the EPM surface layer and the EPM foaming layer was 1:3.
The EPM surface layer and the EPM foaming layer were cooled by laminating rollers. The speed of the laminating rollers was set at 3.0 m/min, thus forming an EPM composite layer (including the EPM surface layer and the EPM foaming layer) having a thickness of about 0.4 mm. The thickness of the EPM surface layer was about 0.1 mm, and the thickness of the EPM foaming layer was about 0.3 mm.
The EPM composite layer was attached to a polyolefin nonwoven fabric by 0.1 mm EPM hot-melt adhesive, thus forming the artificial leather. The attaching process was conducted using a heat roll laminator with a roll surface temperature of 100°C.

Example 3:

EPM adhesive layer (component C): 150°C, 185°C, 180°C
The temperature of the T-die was set at 185°C.
The metering pumps of the component A, the component B and the component C were set, so that the thickness ratio of the EPM surface layer, the EPM foaming layer and the EPM adhesive layer is 1:7:1.
The EPM surface layer, the EPM foaming layer and the EPM adhesive layer were cooled by laminating rollers. The speed of the laminating rollers was set at 2.5 m/min, thus forming an EPM composite layer (including the EPM surface layer, the EPM foaming layer and the EPM adhesive layer) having a thickness of about 0.9 mm. The thickness of the EPM surface layer was about 0.1 mm, the thickness of the EPM foaming layer was about 0.7 mm, and the thickness of the EPM adhesive layer was about 0.1 mm.
A water-based polyurethane covering layer was applied to the EPM surface layer.
The EPM composite layer was attached to a polyolefin nonwoven fabric through the 0.1 mm EPM adhesive layer, thus forming the artificial leather. The attaching process was conducted using a heat roll laminator with a roll surface temperature of 100°C.

Example 4:

Extruder temperature:

EPM surface layer (component A), containing 0%, 10%, 20%, 30%, 50% thermoplastic vulcanize (TPV): 180°C, 210°C, 210°C
The temperature of the T-die was set at 195°C.

The EPM surface layer was extrusion laminated to a nonwoven fabric, and was cooled by cooling rollers. The speed of the laminating rollers was set at 3.0 m/min, thus forming an artificial leather of EPM having a thickness of about 0.8 mm.
The artificial leather was further pressed by embossing rollers having a surface temperature of 100°C, thus forming the surface-textured artificial leather of EPM.
The EPM containing TPV with different contents (as shown below) can provide the artificial leather with improved mechanical properties and hand feel. Test result of Example 4

TPV content 0% 10% 20% 30% 50%

Peel strength (kg/cm) 3.2 3.5 3.7 3.4 3.8

Flex fatigue resistance (cycles) 5,000 20,000 50,000 80,000 100,000

Claims

An artificial leather, comprising:
a fabric layer; and

an ethylene-propylene copolymer (EPM) layer attached to the fabric layer, wherein the EPM layer is an EPM composite layer comprising an EPM foaming layer and an EPM surface layer.
The artificial leather of claim 1, wherein the fabric layer is attached to the EPM foaming layer, and the EPM surface layer is disposed on a surface of the EPM foaming layer opposite to the fabric layer.
The artificial leather of claim 1 or 2, wherein the EPM surface layer presents a texture on a surface opposite to the EPM foaming layer.
The artificial leather of any one of claims 1 to 3, wherein the EPM composite layer further comprises an EPM adhesive layer, and the fabric layer is attached to the EPM composite layer through the EPM adhesive layer.
The artificial leather of any one of claims 1 to 4, further comprising a covering layer disposed on a surface of the EPM layer opposite to the fabric layer.
A method for manufacturing the artificial leather of any one of claims 1 to 5, comprising:
providing the fabric layer;

providing the EPM layer; and

attaching the EPM layer to the fabric layer.
The method of claim 6, comprising forming the EPM foaming layer and the EMP surface layer concurrently.
The method of claim 6 or 7, comprising co-extruding the EPM foaming layer and the EPM surface layer.
The method of any one of claims 6 to 8, wherein the EMP composite layer further comprises an EPM adhesive layer, and the method comprises co-extruding the EPM foaming layer, the EPM surface layer and the EPM adhesive layer.
The method of claim 9, wherein the EPM adhesive layer is a hot-melt adhesive, and the method comprises heat press laminating the EPM adhesive layer to the fabric layer, such that the EPM composite layer is attached to the fabric layer through the EPM adhesive layer.
The method of any one of claims 6 to 10, comprising extrusion laminating the EPM foaming layer to the fabric layer.
The method of any one of claims 6 to 11, further comprising providing a covering layer, and attaching the covering layer to a surface of the EPM layer opposite to the fabric layer.
A shoe structure comprising the artificial leather of any one of claims 1 to 5.