SUEDE-LIKE SYNTHETIC LEATHER AND METHOD OF MAKING THE SAME

Abstract

A suede-like synthetic leather includes a substrate and a suede-like layer formed on the substrate from a polymeric foam which has a surface provided with piles projecting therefrom. The suede-like synthetic leather is formed by a process which includes the steps of forming the polymeric foam on the substrate, and forming the piles on the surface of the polymeric foam by rubbing, tumbling, or abrading the surface of the polymeric foam.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority of Taiwanese Patent Application No. 102145565, filed on Dec. 11, 2013.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a synthetic leather, more particularly to a suede-like synthetic leather that has an appearance and feel substantially similar to those of natural leather and a method of making the same.

2. Description of the Related Art

Natural leather made from animal skins has characteristics, such as good to touch, good texture, high comfort, good flexibility, etc. Thus, the natural leather is widely used in clothings, shoes, gloves, hats, furniture, etc. However, the natural leather is expensive, and has some drawbacks, such as not washable with water, cannot be easily dyed, has low plasticity, easily breed mold so that special care treatment is required, etc. Moreover, with the rising awareness of animal protection, the source of natural leather is increasingly limited, and consumers tend not to buy natural leather. Additionally, conservation awareness is high, so that research and development of man-made synthetic leather having good quality simulating that of natural leather are continually performed.

Although a man-made synthetic leather is quite common nowadays, and is capable of resolving the aforesaid drawbacks of the natural leather, the texture and feel of the existing man-made synthetic leather are still not as good as those of the natural leather. Further, the comfort provided by the existing man-made synthetic leather is poorer when compared to that of the natural leather. Because the natural leather has good texture and feel and is comfortable, it still has a huge market demand and is loved by female consumers. How to improve the appearance and feel of a man-made synthetic leather so that the advantages of the synthetic leather may be retained and so that the man-made synthetic leather may show a closer appearance and feel of the natural leather is a current issue that needs to be resolved.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a suede-like synthetic leather that has an appearance and feel closer to those of natural leather and that is durable.

Another object of this invention is to provide a method of making the aforesaid suede-like synthetic leather.

According to one aspect of this invention, a suede-like synthetic leather comprises a substrate and a suede-like layer formed on the substrate from a polymeric foam which has a surface provided with piles projecting therefrom. The suede-like synthetic leather is formed by a process which includes the steps of forming the polymeric foam on the substrate, and forming the piles on the surface of the polymeric foam by rubbing, tumbling, or abrading the surface of the polymeric foam.

According to another aspect of this invention, a method of making a suede-like synthetic leather comprises the steps of: (a) preparing a foamable liquid composition, the foamable liquid composition including a polymer and a foaming agent; (b) applying the foamable liquid composition on a substrate; (c) heating the substrate to foam the foamable liquid composition and to form a polymeric foam; and (d) forming piles on a surface of the polymeric foam by rubbing, tumbling or abrading the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which:

FIG. 1 is a sectional view of a suede-like synthetic leather according to the first preferred embodiment of the present invention, illustrating a polymeric foam connected to a substrate of the suede-like synthetic leather;

FIG. 2 is another sectional view of the first preferred embodiment, illustrating a suede-like layer of the suede-like synthetic leather formed on the substrate from the polymeric foam;

FIG. 3 is a sectional view of a suede-like synthetic leather according to the second preferred embodiment of the present invention;

FIG. 4 is a sectional view of a suede-like synthetic leather according to the third preferred embodiment of the present invention;

FIG. 5 is a sectional view of a suede-like synthetic leather according to the fourth preferred embodiment of the present invention;

FIG. 6 is a sectional view of a suede-like synthetic leather according to the fifth preferred embodiment of the present invention;

FIG. 7 is a sectional view of a suede-like synthetic leather according to the sixth preferred embodiment of the present invention;

FIG. 8 is a sectional view of a suede-like synthetic leather according to the seventh preferred embodiment of the present invention;

FIG. 9 is a flow chart, illustrating the steps involved in adhering a suede-like synthetic leather according to the eighth preferred embodiment of the present invention to a surface of an article; and

FIG. 10 is a flow chart, illustrating the steps involved in a method of making the suede-like synthetic leather of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before this invention is described in detail, it should be noted that, in the following description, similar elements are designated by the same reference numerals.

Referring to FIGS. 1 and 2, a suede-like synthetic leather according to the first preferred embodiment of the present invention is shown to comprise a substrate 1 and a suede-like layer 2.

The substrate 1 includes a first surface 11, and a second surface 12 opposite to the first surface 11. In this embodiment, the substrate 1 is a fabric selected from the group consisting of polyester, rayon, nylon, polyurethane, polyamide and cotton.

The suede-like layer 2 is formed on the substrate 1 from a polymeric foam 20. In this embodiment, the polymeric foam 20 is formed by coating a foamable liquid composition on the substrate 1, and has a surface provided with piles 22 projecting therefrom. The piles 22 are formed by rubbing, tumbling, or abrading the surface of the polymeric foam 20. Alternatively, because the substrate 1 is a fabric with a porous structure, the polymeric foam 20 may be formed on the substrate 1 using an impregnation method. Through this, the polymeric foam 20 may extend into and fill the porous structure of the substrate 1, so that a tight connecting structure between the substrate 1 and the polymeric foam 20 may be obtained.

The polymeric foam 20, after foaming, has a less compact structure and shows a moderate bulkiness and fullness. As such, the suede-like layer 2 can have a compact structure close to natural leather. Further, the piles 22 show a three-dimensional pile structure and texture, so that the suede-like layer 2 can have an appearance and feel close to those of the natural leather.

Preferably, the polymeric foam 20 has a thickness ranging from 0.1˜2.0 mm. If the thickness of the polymeric foam 20 is greater than 2.0 mm, the lengths of the piles 22 formed after rubbing, tumbling, or abrading are long. This will cause the piles 22 themselves or a connecting structure between the piles 22 and the substrate 1 to easily get damaged due to an external force. For example, the piles 22 are prone to break or fall off due to friction. Thus, the thickness of the polymeric foam 20 is controlled to be less than 2.0 mm. Moreover, if the thickness of the polymeric foam 20 is less than 0.1 mm, it is difficult to form a good suede-like appearance and texture after processing.

Referring to FIG. 10, in combination with FIGS. 1 and 2, a method of making the suede-like synthetic leather according to the first preferred embodiment of this invention comprises steps (a) to (d).

In step (a), a foamable liquid composition is prepared. The foamable liquid composition is uniformly stirred and mixed, so that a uniform compact polymeric foam 20 may be formed through subsequent heating and foaming processes, thereby preventing the polymeric foam 20 to have a non-uniform thickness or poor coherency.

In step (b), the foamable liquid composition is applied on a substrate 1 through an impregnation method or a coating method. In the coating method, a coating device, such as a knife coater, a scratch coater or a roller coater, is used to uniformly coat the foamable liquid composition with a predetermined thickness on the substrate 1. In the impregnation method, the substrate 1 is first impregnated with the foamable liquid composition, after which a roller or a gap roller is used to adjust the amount of the foamable liquid composition absorbed by the substrate 1. The polymeric foam formed by the impregnation method extends into and fills a porous structure of the substrate 1. Thus, as compared to the coating method, the connection between the suede-like layer 2 and the substrate 1 is stronger.

Aside from the aforesaid coating and impregnation methods, during actual manufacture, the connection between the suede-like layer 2 and the substrate 1 may employ other connecting methods, such as using a spray gun to spray the foamable liquid composition onto the substrate 1, or using a printing apparatus to print the foamable liquid composition onto the substrate 1.

In step (c), the substrate 1 is heated so as to foam the foamable liquid composition and to form the polymeric foam 20. The substrate 1 may be heated using a single heating method or a multi-heating method. In the single heating method, the substrate 1 is heated to a temperature sufficient to heat and foam the foamable liquid composition so as to form the polymeric foam 20. In the multi-heating method, the substrate 1 is first heated at a temperature lower than a foaming temperature of the foamable liquid composition to form the foamable liquid composition into a preformed body that is stably connected to the substrate 1. A second heating is applied to the substrate 1. In the second heating, the temperature is raised to the foaming temperature so as to foam the preformed body and to form the polymeric foam 20. In comparing the single heating method with the multi-heating method, because the heating temperature in the single heating method is directly raised to the foaming temperature, the foamable liquid composition is directly heated and foamed. Foaming can be completed at one time only. The polymeric foam 20 formed therefrom is rougher and thicker, and the piles 22 resulting from rubbing or tumbling are longer. Hence, a user can select which heating method to apply in order to obtain an appearance and feel according to the requirement.

Preferably, the heating temperature of the single heating method is in the range of 120˜250□, and the heating time is 2˜5 minutes. More preferably, the heating temperature is 170□, and the heating time is 3 minutes.

Preferably, the heating temperature of the first heating of the multi-heating method is in the range of 40˜100□, and the heating time is 2˜5 minutes; and the heating temperature of the second heating thereof is in the range of 120˜250□, and the heating time is 20 seconds to 5 minutes. More preferably, the heating temperature of the first heating is 70□ and the heating time is 3 minutes, and the heating temperature of the second heating is 170□ and the heating time is also 3 minutes.

The single heating method and the multi-heating method are executed in, for example, an oven. However, other heating devices may be used, such as a heating drum, a thermal oil heater or a lamp that can control thermal power.

In step (d), one of rubbing, tumbling or abrading process is performed on the surface of the polymeric foam 20 to form the piles 22. Rubbing or tumbling may be performed using a manual method or a device similar to a tumbler. In the latter case, the substrate 1 together with the polymeric foam 20 is placed in the tumbler. By controlling an operation mode or speed of the tumbler, a different effect of rubbing or tumbling can be obtained. Generally, the piles 22 of the suede-like layer 2 after going through the rubbing or tumbling process has a feel and an appearance that are rough. The abrading process may be performed using a grinder, a brush roller or a sandpaper of particular specification. The piles 22 are finer and smoother after abrading, and have a soft feel closer to natural leather.

Further, after performing one of rubbing, tumbling or abrading process, a spray printing machine or a printing press may be further use to treat color reparation or color fastness of the suede-like body 2 so as to enhance color uniformity and durability of the suede-like body 2.

It should be noted that, in step (a), the prepared foamable liquid composition includes a polymer, a foaming agent, a solvent, a thickener and an additive. Preferably, the foamable liquid composition has a viscosity ranging from 200˜15000 cps. The viscosity range of the foamable liquid composition can be adjusted using the coating or impregnation method.

The polymer is selected from polyurethane resins. The foaming agent includes microspheric powder particles each having a particle shell filled with nitrogen gas. After heating, each particle shell becomes soft, and the nitrogen gas inside the particle shell expands due to heat, thereby expanding the volume of the particle shell. Preferably, each particle has a diameter ranging from 6 μm˜50 μm. By selecting different sizes of the microspheric powder particles, pore size and density of the polymeric foam 20 after foaming can be controlled, thereby further controlling roughness of the surface of the suede-like layer 2. If the particles of large diameter are used, the pores formed after heating and foaming are large, and the surface of the suede-like body 2 is rough. Through this, the feel of the synthetic leather can be adjusted in response to different purpose of application and design requirement.

The solvent is mainly used to dilute the polymer to form a liquid body that can be uniformly stirred and mixed. Preferably, the solvent is selected from one of methyl ethyl ketone (MEK), isopropyl alcohol (IPA), ethyl acetate (EAC) and acetone. In this embodiment, the solvent is methyl ethyl ketone.

The thickener is mainly used to adjust the final viscosity of the foamable liquid composition. Preferably, the thickener is selected from one of calcium carbonate and wood flour. In this embodiment, the thickener is wood flour.

The additive is added according to a product requirement. Preferably, the additive is selected from the group consisting of pigment, wax powder, surfactant and feeling agent. The additive is added to increase the appearance diversity or provide a particular feel of the product, for example, forming a specific color, enhance dryness or smoothness of a surface, etc. In this embodiment, the additive is wax powder.

Preferably, the foamable liquid composition includes 100 parts by weight of polymer, 2˜8 parts by weight of foaming agent, 40˜100 parts by weight of solvent, 1˜10 parts by weight of thickener, and 2˜6 parts by weight of additive. In this embodiment, the foamable liquid composition includes 100 parts by weight of polymer, 3 parts by weight of foaming agent, 80 parts by weight of solvent, 8 parts by weight of thickener, and 2 parts by weight of additive.

The solvent of the foamable liquid composition in this embodiment is an organic solvent, but is not limited thereto. Based on environmentally friendly, economic and safety considerations, the solvent may be water. In this case, a water-based foamable liquid composition includes a polymer, a foaming agent, a solvent, a water-based crosslinker, a water-based thickener, and an additive. A suede-like synthetic leather that conforms to the requirement may also be produced using the water-based foamable liquid composition. Preferably, the viscosity of the water-based foamable liquid composition is in the range of 200˜15000 cps.

The polymer of the water-based foamable liquid composition is selected from water-based polyurethane resins. The foaming agent of the water-based foamable liquid composition is similar to that of the foamable liquid composition that uses the organic solvent, and includes microspheric powder particles each having a diameter ranging from 6 μm˜50 μm. The solvent is water. The thickener and the water-based crosslinker are thickener and water-based crosslinker that are commonly used in the leather industry. The additive is selected from the group consisting of water-based pigment and water-based feeling agent. In this embodiment, the additive is water-based feeling agent.

Since the water-based polyurethane resin has low molecular weight, the chemical crosslinking formed therefrom has low density. This may adversely affect the water resistance, thermal stability, and mechanical strength such as tensile stress and strain of the product produced therefrom. Therefore, in order to produce a stronger structural strength of suede-like structure, a water-based crosslinker is added so that hydrophilic carboxylic acid of the polyurethane molecule forms a hydrophobic amino ester bond. Through this, the density of the crosslinker, water resistance, thermal stability, and mechanical strength of the water-based polyurethane resin can be greatly enhanced.

Preferably, the water-based foamable liquid composition includes 100 parts by weight of polymer, 2˜8 parts by weight of foaming agent, 5˜10 parts by weight of solvent, 1˜6 parts by weight of water-based thickener, 5˜10 parts by weight of water-based crosslinker, and 2˜6 parts by weight of additive. In this embodiment, the water-based foamable liquid composition includes 100 parts by weight of polymer, 3 parts by weight of foaming agent, 5 parts by weight of solvent, 1 part by weight of water-based thickener, 5 parts by weight of water-based crosslinker, and 2 parts by weight of additive.

Referring to FIG. 3, a suede-like synthetic leather according to the second preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the surface of suede-like layer 2 not only has a pile structure, but also has a three-dimensional pattern 23. The surface of the suede-like layer 2 may have different designs or patterns, and may be designed according to the requirement. Hence, the diversity of the appearance of the suede-like synthetic leather of this embodiment can be enhanced.

To form the three-dimensional pattern 23 on the surface of the suede-like layer 2, prior to forming of the polymeric foam 20 in step (c), the foamable liquid composition is coated on a surface of a release paper (not shown) having a three-dimensional raised pattern, and is dried by heating at a temperature lower than the foaming temperature so as to form the preformed body. Next, a polyurethane adhesive is used to connect the preformed body and the substrate 1. After the adhesive is completely dried, the release paper is removed. The substrate 1 together with the preformed body is then heated to the foaming temperature so as to form the polymeric foam 20 having a three-dimensional patterned surface. Another alternative step is to initially dry the foamable liquid composition or the preformed body by heating at a temperature lower than the foaming temperature, after which a high temperature pressure roller (not shown) having a raised patterned surface is used to simultaneously perform embossing and foaming steps. The polymeric foam 20 having a three-dimensional patterned surface can be similarly obtained. After performing the rubbing, tumbling or abrading process, the suede-like layer 2 having the three-dimensional pattern 23 can be formed. Apart from this, a printing roller having a raised pattern of a printing machine may be used to coat the foamable liquid composition on the substrate 1, and after heating and foaming, the suede-like layer 2 having the three-dimensional pattern 23 may be similarly formed.

Referring to FIG. 4, a suede-like synthetic leather according to the third preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the suede-like synthetic leather further comprises a first adhesive layer 3 disposed between the first surface 11 of the substrate 1 and the suede-like layer 2. The material of the first adhesive layer 3 is selected from polymers. Preferably, the polymer selected for the first adhesive layer 3 is similar to that of the suede-like layer 2. In this embodiment, the first adhesive layer 3 is made of a polyurethane resin.

The first adhesive layer 3 can be similarly formed on the substrate 1 using a coating method or an impregnation method. When the impregnation method is used, the first adhesive layer 3 fills up the pores of the substrate 1 and extends out of the first surface 11 to connect with the suede-like layer 2. Through this, a tight connection between the first adhesive layer 3 and the substrate 1 can be formed. Simultaneously, the structure of the substrate 1 can be fixed and strengthened.

Because the suede-like layer 2 and the first adhesive layer 3 are made of similar materials, the suede-like layer 2 can be securely connected to the substrate 1. Through this, firmness of the suede-like synthetic leather can be enhanced.

To make the suede-like synthetic leather of the third preferred embodiment, a polymer coating solution is first coated on the first surface 11 of the substrate 1. The polymer coating solution includes a polymer, a solvent, a thickener, and an additive. Preferably, the polymer is selected from polyurethane resins, the solvent is selected from dimethyl formamide (DMF), the thickener is selected from one of calcium carbonate and wood flour, and the additive is added according to the product requirement and is selected from the group consisting of pigment, surfactant and feeling agent. In this embodiment, the thickener is wood flour, and the additive is feeling agent.

Preferably, the polymer coating solution includes 100 parts by weight of polymer, 40˜80 parts by weight of solvent, 2˜10 parts by weight of thickener, and 3˜6 parts by weight of additive. In this embodiment, the polymer coating solution includes 100 parts by weight of polymer, 50 parts by weight of solvent, 5 parts by weight of thickener, and 5 parts by weight of additive. Preferably, the viscosity of the polymer coating solution is in the range of 1000˜12000 cps.

In this embodiment, the polymer used in the polymer coating solution is similar to that in the foamable liquid composition of the polymeric foam 20, so that the first adhesive layer 3 and the suede-like layer 2 can have a tight connection. However, in actual manufacture, the polymer may be made of polyvinyl chloride (PVC) or water-based polyurethane resins, and is not limited to the disclosed embodiment.

By using a squeeze roller set (not shown) of a wet machine, the polymer coating solution coated on the first surface 11 of the substrate 1, after being solidified and water washed to discharge the solvent, is then dried to form the first adhesive layer 3. Afterwards, the polymeric foam 20 is made using the same method described in the first or second preferred embodiment, and is then processed to form the suede-like layer 2 or the suede-like layer 2 having the three-dimensional pattern 23.

Preferably, in order for the first adhesive layer 3 to be stably connected not only to the suede-like layer 2, but also be tightly connected to the substrate 1, the first adhesive layer 3 may also be formed using an impregnation method. In this method, a polymeric impregnating solution is first prepared. The polymeric impregnating solution contains chemicals similar to those of the polymer coating solution. The main difference resides in that the value of viscosity of the polymeric impregnating solution is smaller than that of the polymer coating solution. The polymeric impregnating solution includes 100 parts by weight of polymer, 400˜600 parts by weight of solvent, 1˜10 parts by weight of thickener, and 1˜3 parts by weight of additive. Preferably, the polymeric impregnating solution includes 100 parts by weight of polymer, 400 parts by weight of solvent, 3 parts by weight of thickener, and 3 parts by weight of additive. Preferably, the viscosity of the polymeric impregnating solution is in the range of 100˜1600 cps.

The substrate 1 is then impregnated with the prepared polymeric impregnating solution, after which a roller or a gap roller is used to adjust the amount of the impregnating solution absorbed by the substrate 1. After being solidified and water washed to discharge the solvent, the polymeric impregnating solution is then dried to form the first adhesive layer 3.

The polymeric impregnating solution is prepared with a viscosity lower than that of the polymer coating solution, so that the impregnating solution can easily penetrate the porous structure of the substrate 1. After the impregnating solution is solidified, water washed and dried, the coating or impregnating operation of the foamable liquid composition proceeds. The foamable liquid composition is then dried to form the polymeric foam 20 and the suede-like layer 2 or the suede-like layer 2 having the three-dimensional pattern 23. Through this, the first adhesive layer 3 can fill up the pores of the substrate 1 and extend out of the first surface 11 to connect with the suede-like layer 2. Thus, a tight connecting structure is formed between the substrate 1 and the first adhesive layer 3.

A coating and penetrating method may also be used to form the first adhesive layer 3 apart from the aforesaid impregnation and coating methods. In this method, the polymer coating solution is diluted, and the viscosity is lowered to 1000˜2200 cps. The viscosity of the polymer coating solution is adjusted based on the material and thickness of the substrate 1. The diluted polymer coating solution is coated on the substrate 1 to gradually penetrates into the porous structure of the substrate 1, and is solidified, water washed and dried. Afterwards, coating and drying of the foamable liquid composition proceed to form the polymeric foam 20 and the suede-like layer 2 or the suede-like layer 2 having the three-dimensional pattern 23. As such, with the first adhesive layer 3 filling up the pores of the substrate 1, a tight connection structure between the substrate 1 and the first adhesive layer 3 can be formed.

Referring to FIG. 5, a suede-like synthetic leather according to the fourth preferred embodiment of the present invention is shown to be similar to the third preferred embodiment. However, in this embodiment, the first adhesive layer 3 is connected to the second surface 12 of the substrate 1 and is opposite to the suede-like layer 2.

The method of making this embodiment is similar to that described in the third preferred embodiment. The difference resides in that the first adhesive layer 3 is connected to the second surface 12 of the substrate 1. A detailed description thereof is dispensed herewith.

Referring to FIG. 6, a suede-like synthetic leather according to the fifth preferred embodiment of the present invention is shown to be similar to the third preferred embodiment. However, in this embodiment, the suede-like synthetic leather further comprises a second adhesive layer 4 formed on the second surface 12 of the substrate 1. The first and second adhesive layers 3, 4 are formed of polymers, preferably similar to that of the suede-like layer 2. In this embodiment, each of the first and second adhesive layers 3, 4 is made of a polyurethane resin.

In this embodiment, the suede-like layer 2 is formed connected to the first adhesive layer 3. In an alternative embodiment, another suede-like layer 2 may be formed connected to the second adhesive layer 4. In this case, the suede-like synthetic leather has both surfaces formed with suede-like structures. Through the provision of the first and second adhesive layers 3, 4, the structure of the substrate 1 can be similarly strengthened. Further, the thickness of the suede-like synthetic leather can be adjusted according to the requirement.

The method of making this embodiment is similar to that described in the third preferred embodiment. In this embodiment, a prepared polymer coating solution is first coated on the first surface 11 of the substrate 1, and is then solidified, water washed and dried to form the first adhesive layer 3. The polymer coating solution is also coated on the second surface 12 of the substrate 1, and is solidified, water washed and dried to form the second adhesive layer 4. The suede-like layer 2 is made using the method described in the first preferred embodiment.

Referring to FIG. 7, a suede-like synthetic leather according to the sixth preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the suede-like synthetic leather further comprises an impregnation layer 5 filling the pores of the substrate 1 and extending out of the first and second surfaces 11, 12 of the substrate 1. The impregnation layer 5 includes a penetrating portion 51 distributed inside the substrate 1, a first connecting portion 52 extending out of the substrate 1 from the penetrating portion 51 through the first surface 11 to connect with the suede-like layer 2, and a second connecting portion 53 extending out of the substrate 1 from the penetrating portion 51 through the second surface 12.

Through the provision of the impregnation layer 5 that penetrates and covers the substrate 1, the structure of the substrate 1 can be further fixed and strengthened, and the connection between the substrate 1 and the suede-like layer 2 can be more secured. By controlling the thickness of the impregnation layer 5, the entire thickness of the suede-like synthetic layer can be adjusted according to the requirement.

To make the suede-like synthetic leather of the sixth preferred embodiment, a machine (not shown) is used to completely impregnate the substrate 1 with a prepared polymeric impregnating solution, so that the polymeric impregnating solution can penetrate inside the substrate 1, and the first and second surfaces 11, 12 of the substrate 1 are filled with the polymeric impregnating solution. After the amount of the polymeric impregnating solution absorbed by the substrate 1 is adjusted, a squeeze roller set (not shown) is used to solidify the absorbed polymeric impregnating solution and to discharge the solvent in the polymeric impregnating solution. The substrate 1 together with the polymeric impregnating solution is then dried to form the impregnation layer 5 that fills the pores of the substrate 1, that extends out of the first and second surfaces 11, 12 of the substrate 1, and that has the penetrating portion 51 and the first and second connecting portions 52, 53. Afterwards, the suede-like layer 2 is made using the method described in the first preferred embodiment. The forming of the impregnation layer 5 is not limited to the impregnation method. The impregnation layer 5 may be formed using a coating and penetrating method described above.

Referring to FIG. 8, a suede-like synthetic leather according to the seventh preferred embodiment of the present invention is shown to be similar to the sixth preferred embodiment. However, in this embodiment, the suede-like synthetic leather further comprises a first adhesive layer 3 connected between the first connecting portion 52 of the impregnation layer 5 and the suede-like layer 2, and a second adhesive layer 4 connected to the second connecting portion 53 of the impregnation layer 5.

The impregnation layer 5 and the first and second adhesive layers 3, 4 are all formed of polymers, and preferably are selected from a polymeric material similar that of the suede-like layer 2. The impregnation layer 5 and the first and second adhesive layers 3, 4 are made of polyurethane resins.

Through the provision of the impregnation layer 5, the structure of the substrate 1 can be further fixed and strengthened, and the connection of the substrate 1 with the first and second adhesive layers 3, 4 and the suede-like layer 2 can be more secured. Further, by controlling the thickness of the impregnation layer 5 and the first and second adhesive layers 3, 4, the entire thickness of the suede-like synthetic layer can be adjusted according to the requirement.

The method of making this embodiment is similar to that described in the sixth preferred embodiment. In this embodiment, the polymer coating solution can be coated on the first connecting portion 52 without waiting for the impregnation layer 5 to dry completely, and is then solidified, water washed and dried to form the first adhesive layer 3. Next, the polymer coating solution is coated on the second connecting portion 53, and is then solidified, water washed and dried to form the second adhesive layer 4. Afterwards, the suede-like layer 2 is made using the method described in the first preferred embodiment, so that the suede-like layer 2 is formed on the first adhesive layer 3.

Referring to FIG. 9, a suede-like synthetic leather according to the eighth preferred embodiment of the present invention is shown to be similar to the first preferred embodiment. However, in this embodiment, the substrate 6 has a multi-layered structure, and includes a fabric layer 61, and a non-foamed polymeric film layer 62 releasably connected to the fabric layer 61. The suede-like layer 2 is connected to a surface of the polymeric film layer 62 opposite to the fabric layer 61.

Preferably, the polymeric film layer 62 is made from one of water-based and oil-based polyurethane resins. The fabric layer 61 is a releasable fabric. Through a special treatment, a polymer solution coated on a surface of a fabric material is processed and treated to form a polyurethane film, so that the fabric material can be completely and easily releasable, and is also called a separation cloth.

If it is desired for a surface of an article 7, such as furniture, a decoration board, etc., to have an appearance and feel similar to those of leather, the polymeric film layer 62 is first released from the fabric layer 61, and is then adhered to the article 7. The polymeric film layer 62 has a characteristic of supporting and enhancing the stability of the suede-like layer 2. Through this, the suede-like layer 2 cannot easily deform when adhered to the surface of the article 7, thereby giving the article 7 an appearance and feel similar to those of suede leather. Hence, not only is the appearance of the article 7 can be changed, the use of this embodiment is also easy. Moreover, the polymeric film layer 62 may also be connected to a split leather (not shown), after which the split leather is connected to the surface of the suede-like layer 2 so as to present a suede feel and forma special appearance and texture. The suede-like layer 2 is more durable in this case.

To make the suede-like synthetic leather of this embodiment, a polymer coating solution is first coated on the fabric layer 61 of the substrate 6, and is then solidified, water washed and dried to form the non-foamed polymeric film layer 62. Afterwards, the suede-like layer 2 is made using the method described in the first preferred embodiment such that the suede-like layer 2 is connected with the non-foamed polymeric film layer 62.

In the description of each preferred embodiment, the substrate 1 or the fabric layer 61 of the substrate 6 may be made by a weaving method, such as plain weaving, interweaving or knitting, or may be made by using a needle punching or spunlacing method to fabricate a nonwoven fabric or a spunlaced fabric. However, in actual manufacture, the substrate 1 or the fabric layer 61 of the substrate 6 is not limited to the same fibrous material, and may be a mixture of different materials. For example, polyester microfiber and polyamide microfiber are mixed in a predetermined proportion to make the substrate 1 or the fabric layer 61 of the substrate 6. Further, the substrate 1 may be made of an environmentally friendly polyvinyl chloride (PVC) material.

It is worth mentioning that, in the aforesaid third to eighth preferred embodiments, the surface of the suede-like layer 2 may be formed with the three-dimensional pattern 23 described in the second preferred embodiment, so that the surface of the suede-like layer 2 has the pile structure and the three-dimensional pattern 23 simultaneously. Through this, the appearance of the suede-like synthetic leather can be increasingly varied.

The advantages and effects of the suede-like synthetic leather of this invention and the method of making the same can be summarized as follows:

• • 1. The foamable liquid composition is applied on the substrate 1, and is heated to form the polymeric foam 20 having a less compact structure, presenting a moderate bulkiness and fullness, and stably connected to the substrate 1. Further, by using microspheric powder particles as the foaming agent, apart from a more environmentally friendly foaming process to manufacture the polymeric foam, the sizes of the microspheric powder particles can also be selected to control the pore size and density of the polymeric foam 20. Through this, the roughness of the surface of the suede-like layer 2 can be controlled. Hence, the feel of the surface of the synthetic leather of this invention can be easily adjusted in response to different applications and requirements.
  • 2. By selecting different heating method or process, the thickness of the polymeric foam 20 and the lengths of the piles 22 of the suede-like layer 2 can be controlled so as to present different textures. Similarly, the physical characteristics of the synthetic leather of this invention can be adjusted in response to different applications and requirements to conform with the demand for diversity.
  • 3. The polymeric foam 20 is further treated to form the suede-like layer 2. Since the thickness of the polymeric foam 20 can be controlled to a desired thickness range, the polymeric foam 20 can be controlled to produce the piles 22 that cannot be easily broken or produced dander due to friction, so that the pile structure of the suede-like synthetic leather is not easily damaged and has a strong structure. The durability and practicality of the suede-like synthetic leather of this invention can thus be enhanced.
  • 4. Through rubbing, tumbling, abrading or embossing of the surface of the polymeric foam 20, the suede-like layer 2 can present a three-dimensional suede structure, and has an appearance and soft feel closer to those of natural leather, so that the resulting suede-like layer 2 has a diversified suede-like appearance or feel. Through this, the suede-like synthetic leather of this invention can present different surface feel and appearance after adjustment. Different design requirements or appearance can be widely met.

While the present invention has been described in connection with what are considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.

Claims

1. A suede-like synthetic leather, comprising:

a substrate; and

a suede-like layer formed on said substrate from a polymeric foam which has a surface provided with piles projecting therefrom;

wherein said suede-like synthetic leather is formed by a process which includes the steps of:

forming said polymeric foam on said substrate; and

forming said piles on said surface of said polymeric foam by rubbing, tumbling, or abrading said surface of said polymeric foam.

2. The suede-like synthetic leather of claim 1, wherein said polymeric foam is a water-based polyurethane foam.

3. The suede-like synthetic leather of claim 1, wherein said polymeric foam has a thickness ranging from 0.1˜2.0 mm.

4. The suede-like synthetic leather of claim 1, wherein said substrate has a first surface connected with said suede-like layer, and a second surface opposite to said first surface, said suede-like synthetic leather further comprising a first adhesive layer disposed between said first surface of said substrate and said suede-like layer.

5. The suede-like synthetic leather of claim 4, wherein said substrate is a fabric having a porous structure, said suede-like synthetic leather further comprising an impregnation layer filling pores of said substrate and extending out of said substrate through said first surface to connect with said first adhesive layer, said impregnation layer including a penetrating portion distributed inside said substrate, a first connecting portion extending out of said substrate from said penetrating portion through said first surface to connect with said suede-like layer, and a second connecting portion extending out of said substrate from said penetrating portion through said second surface.

6. The suede-like synthetic leather of claim 1, wherein said substrate includes a fabric layer, and a polymeric film layer connected to said fabric layer, said suede-like layer being connected to a surface of said polymeric film layer opposite to said fabric layer, said polymeric film layer being a polyurethane film.

7. The suede-like synthetic leather of claim 1, wherein said substrate is a fabric selected from the group consisting of polyester, rayon, nylon, polyurethane, polyamide and cotton.

8. The suede-like synthetic leather of claim 1, wherein said surface of said suede-like layer is patterned to be a three-dimensional patterned surface.

9. A method of making a suede-like synthetic leather, comprising the steps of:

(a) preparing a foamable liquid composition, the foamable liquid composition including a polymer and a foaming agent;

(b) applying the foamable liquid composition on a substrate;

(c) heating the substrate to foam the foamable liquid composition and to form a polymeric foam; and

(d) forming piles on a surface of the polymeric foam by rubbing, tumbling or abrading the surface.

10. The method of claim 9, wherein in step (b), the foamable liquid composition is applied on the substrate by a coating method using an applicator or an impregnation method.

11. The method of claim 9, wherein in step (a), a viscosity of the foamable liquid composition is adjusted to be in the range of 200˜15000 cps.

12. The method of claim 9, wherein in step (a), the polymer is selected from polyurethane resins, and the foaming agent includes microspheric powder particles each having a diameter ranging from 6 μm˜50 μm.

13. The method of claim 9, wherein in step (a), the foamable liquid composition further includes a solvent and a thickener, and a viscosity of the foamable liquid composition is adjusted to be in the range of 200˜15000 cps.

14. The method of claim 13, wherein in step (a), the solvent is selected from one of methyl ethyl ketone (MEK), isopropyl alcohol (IPA), ethyl acetate (EAC) and acetone, and the thickener is selected from one of calcium carbonate and wood flour.

15. The method of claim 9, wherein in step (a), the polymer is a water-based polyurethane resin, the foaming agent includes microspheric powder particles each having a diameter ranging from 6 μm˜50 μm, and the foamable liquid composition further includes a solvent which is water.

16. The method of claim 15, wherein in step (a), the foamable liquid composition further includes a water-based thickener and a water-based crosslinker.

17. The method of claim 9, wherein in step (c), the substrate is heated at a temperature in the range of 120˜250□ for 2˜5 minutes.

18. The method of claim 9, wherein in step (c), the substrate is first heated at a temperature lower than a foaming temperature to form the foamable liquid composition into a preformed body, after which the substrate is heated a second time at a temperature to foam the preformed body, the substrate being heated at a temperature in the range of 40˜100□ for 2˜5 minutes in the first heating, and at a temperature in the range of 120˜250□ for 20 seconds to 5 minutes in the second heating.

19. The method of claim 9, wherein step (b) includes step (b-1) and step (b-2), in step (b-1), a polymeric adhesive is coated on a surface of the substrate, and is solidified, water washed and dried to form a first adhesive layer; and in step (b-2), the foamable liquid composition is applied on the first adhesive layer.

20. The method of claim 9, wherein the substrate used in step (b) is a porous fabric, and step (b) includes step (b-1) and step (b-2), in step (b-1), a polymeric impregnating solution is coated on the substrate, and is solidified, water washed and dried to form a impregnation layer that penetrates and covers the substrate; and in step (b-2), the foamable liquid composition is applied on at least one surface of the impregnation layer.

21. The method of claim 9, wherein the substrate used in step (b) is a porous fabric, and step (b) includes step (b-1), step (b-2) and step (b-3), in step (b-1), a polymeric impregnating solution is coated on the substrate, and is solidified, water washed and dried to form an impregnation layer that penetrates and covers the substrate; in step (b-2), a polymeric adhesive having a viscosity larger than that of the polymeric impregnating solution is coated on at least one surface of the impregnation layer, and is solidified, water washed and dried to form a first adhesive layer; and in step (b-3), the foamable liquid composition is applied on the first adhesive layer.

22. The method of claim 9, wherein in step (b), wherein the substrate used in step (b) has a fabric layer and a non-foamed polymeric film layer connected to the fabric layer, and step (b) includes step (b-1) and step (b-2), in step (b-1), a polymer coating solution is applied on the fabric layer, and is solidified, water washed and dried to form the non-foamed polymeric film layer; and in step (b-2), the foamable liquid composition is applied on the non-foamed polymeric film layer.

23. The method of claim 9, wherein in step (b), the foamable liquid composition is coated on a surface of a release paper having a three-dimensional raised pattern, and is dried by heating at a temperature lower than a foaming temperature to form a preformed body, the preformed body being connected to the substrate using a polyurethane adhesive, the release paper being removed after the polyurethane adhesive is completely dried; and in step (d), the polymeric foam has a three-dimensional patterned surface.

24. The method of claim 9, wherein in step (c), an embossed method is used to form a raised pattern on a surface of the polymeric foam, and in step (d), the polymeric foam has a three-dimensional patterned surface.