WO2007139247A1

WO2007139247A1 - Method for manufacturing multi -layer sheet, and multi -layer sheet using the same

Info

Publication number: WO2007139247A1
Application number: PCT/KR2006/002390
Authority: WO
Inventors: Hee-Dae Park
Original assignee: Hee-Dae Park
Priority date: 2006-05-25
Filing date: 2006-06-20
Publication date: 2007-12-06
Also published as: KR100870365B1; KR20070113542A

Abstract

The present invention is to embody a method for manufacturing a multi-layer sheet, in which a color TPU layer of 0.15 mm or less can be provided, instead of a screen or printing work, in any one layer selected from multiple layers, and, at the time of coloring, a VOC of a printing ink (solvent type) can be removed, and extrusion can be performed at a time, without an adhesive and a bonding process, in a 3 layer T-die process. The present invention provides a method for embossing the multi-layer sheet even without using a separate release paper having a pattern (Hereinafter, referred to as 'embossing'), such as a design or an embossing, formed therein. In other words, the present invention is to manufacture the multi-layer sheet by allowing a passage of an embossing roller, thereby providing the same surface effect as that of a protrusion and depression of a surface provided using a conventional release paper (R/P) pattern.

Description

METHOD FOR MANUFACTURING MULTI-LAYER SHEET, AND MULTI-LAYER

SHEET USING THE SAME

Technical Field The present invention relates to a method for manufacturing a multi-layer sheet, and more particularly, to a method for manufacturing a multi-layer sheet, for providing an embossing layer based on various colors without using a release paper, and a multi-layer sheet with a color Thermoplastic PolyUrethane (TPU) layer manufactured using the method.

Background Art

As well known in the art, a sheet comprised of multiple layers (for example, polyurethane synthetic leather: hereinafter, referred to as "multi-layer sheet") is artificial leather manufactured by coating fabrics such as a nonwoven fabric with polyurethane resin. As a coating method, there are a wet method and a dry method. First, the wet method is a method for manufacturing the multi-layer sheet by dipping the nonwoven fabric in polyurethane impregnation liguid to impregnate polyurethane resin into the nonwoven fabric, solidifying the polyurethane resin in a solidification bath, coating the solidified impregnated fabric with a proper amount of wet silver surface coating polyurethane, again solidifying the coated fabric in the solidification bath, washing remnant solvent remaining in the fabrics, and drying the fabrics.

The dry method is to manufacture the multi-layer sheet with the design by coating a gel-state polyurethane resin on a release paper with a design, forming the design (or an embossing) , putting, heating, drying and curing the release paper in a heat chamber, coating the cured release paper with adhesive polyurethane, bonding the release paper with the fabrics, heating and drying the resultant, adhering the cured polyurethane film and fabrics to the release paper, and peeling off the release paper.

The dry method is disclosed in Korean Patent Number: 10-0344110 (polyurethane artificial leather and its manufacturing method) and Korean Utility Model Registration Number: 20-0406173 (thermoplastic polyurethane sheet).

However, in the earlier filed invention, since a PU coating layer 3 is coated on a release paper with a pattern, and a PU adhesive layer 4 is coated thereon to form a design at a multi-layer sheet, a work process and a work time are increased and, since work processing and outsourcing are performed at several times, a process cost is increased. In addition, there is an advantage in that, due to poor adhesive force with a thermosetting sheet (TPU) 1, the PU coating layer 3 is peeled off at the time of high frequency work. In the earlier filed utility model, there is a drawback that, since a TPU skin layer 26 is formed on a release paper 28 with an embossing design or hologram, and a TPU adhesive layer (hot melt coating) 24 is coated thereon, a work process and a work time are not only delayed but also a process cost is increased as in the earlier filed invention.

When the multi-layer sheet manufactured in the dry method is colored, the release paper with the design is coated with polyurethane and is adhered to fabrics using an oil adhesive, the release paper is removed, the polyurethane coating layer is printed by various colors using a screen method or a printing method.

However, when the oil adhesive is used as above, there is an advantage that, due to demethylformamide and methylethylketone compositions of polyurethane which is coated on the release paper for printing of the multi-layer sheet, dye flows down and blots on the fabrics, and due to a use of volatile organic solvent, volatile organic chemical material emits into air during the work process (that is, heat treatment) , thereby causing environmental pollution and giving a lethal affection to a human body. In addition, the printing work gets troublesome and temporal and economic wastes are caused, and since a printing layer is separately formed, a scratch is generated.

Disclosure Technical Problem

Accordingly, the present invention is directed to a method for manufacturing a multi-layer sheet, and a multilayer sheet using the same that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method for manufacturing a multi-layer sheet having a thermoplastic polyurethane color film layer.

Another object of the present invention is to provide a manufacturing method for forming a design or an embossing on a sheet without using a patterned release paper.

A further another object of the present invention is to provide a manufacturing method for embodying various colors in a sheet even without a separate printing work. A yet another object of the present invention is to provide a method for manufacturing a multi-layer sheet, which does not require a bonding process, without using a separate adhesive .

A still another object of the present invention is to provide a manufacturing method for forming a glass bead layer in a multi-layer sheet, even without using a separate film paper having a glass bead layer formed therein.

A still another object of the present invention is to provide a multi-layer sheet with a color TPU layer manufactured using a method as above.

A still another object of the present invention is to provide a multi-layer sheet having a color TPU layer or a glass bead layer by a 3 layer T-die process.

A still another object of the present invention is to provide a multi-layer sheet with an embossing formed. Technical Solution

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, there is provided a method for manufacturing a multi-layer sheet with a color TPU

(thermoplastic polyurethane) layer. The method includes steps of mixing thermoplastic polyurethane with pigment, and preparing a resin series composition; and extruding the mixture liquid and resin at a time in a co-extrusion process, and forming the colored color TPU layer and at least one resin layer formed of the resin.

In another aspect of the present invention, there is provided a method for manufacturing a multi-layer sheet with a color TPU layer. The method includes steps of mixing thermoplastic polyurethane with glass bead, mixing thermoplastic polyurethane with pigment, and selectively preparing a resin series composition; and extruding each mixture liquid and the selective resin at a time in a co- extrusion process, and selectively forming a glass bead layer and the colored color TPU layer or a resin layer.

Advantageous Effects

According to the present invention, color can be embodied at the time of an extrusion process without a printing work (or screen printing work) , thereby removing a VOC regulation material of a printing ink, and reducing printing cost and time and a product cost. In addition, extrusion can be performed at a time without a bonding process, thereby manufacturing a multi-layer TPU sheet. Thus, there is an advantage that a work process and a work time can be reduced, and a use of an adhesive is not required at all.

Also, the present invention has an advantage that an unnecessary process, such as a printing work and a release paper separating work, can be removed, thereby simplifying a manufacturing method of the multi-layer sheet, and that a scratch is not generated since a separate printing layer is not formed.

The present invention has an advantage that, without using a separate film paper to which a glass bead layer is adhered, extrusion can be performed at a time using a co- extrusion process, thereby manufacturing the multi-layer sheet in which the glass bead layer is integrally formed, and the multi-layer sheet can also reduce a work process and a work time.

In particular, the present invention has an effect that the multi-layer sheet is improved in quality and a high- frequency cutting power is not only improved but also a physical property of TPU itself is kept and a color quality and a sheet surface (cosmetic) get better.

Description of Drawings

FIG. 1 illustrates a method for manufacturing a multilayer sheet having a color TPU layer and an uppermost embossing according to a preferred embodiment of the present invention; FIG. 2 illustrates a detail of a roller passing step (3f) of FIG. 1;

• FIGS. 3A to 3D illustrate a cross-section of a multilayer sheet having a color TPU layer and an uppermost embossing according to a manufacturing method of the present invention;

FIGS. 4A to 4C illustrate a cross-section of a multilayer sheet having a color TPU layer, a glass bead layer, and an uppermost embossing according to a manufacturing method of the present invention; FIG. 5 illustrates a cross-section of a multi-layer sheet when an uppermost embossing is removed using a laser work, from the multi-layer sheet that is made according to a manufacturing method of the present invention; and

FIG. 6 is a three-dimensional view illustrating the multi-layer sheet of FIG. 5. Best Mode for Carrying out the Invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to accompanying drawings. The present invention is to embody a method for manufacturing a multi-layer sheet, in which a color TPU layer of 0.15 mm or less can be provided, instead of a screen or printing work, in any one layer selected from multiple layers, and, at the time of coloring, a VOC of a printing ink (solvent type) can be removed, and extrusion can be performed at a time, without an adhesive and a bonding process, in a 3 layer T-die process.

Also, the present invention provides a method for manufacturing the multi-layer sheet in which, without using a separate film paper having a glass bead layer formed therein, a glass bead layer and a color TPU layer are integrally formed by performing the extrusion at a time using the 3 layer T-die process. When the extrusion is performed at a time using the 3 layer T-die process, if resin is extruded together, the multi-layer sheet in which the glass bead layer, the color TPU layer, and a resin layer are integrally formed can be manufactured.

The present invention provides a method for embossing the multi-layer sheet even without using a separate release paper having a pattern (Hereinafter, referred to as "embossing") , such as a design or an embossing, formed therein. In other words, the present invention is to manufacture the multi-layer sheet by allowing a passage of a roller whose surface is embossed, thereby providing the same surface effect as that of a protrusion and depression of a surface provided using a conventional release paper (R/P) pattern.

As described above, a technological feature intended by the present invention is to, when the multi-layer sheet is manufactured, form the color TPU layer without the separate release paper or the printing work, or form the glass bead layer without using a separate film paper. In other words, the technological feature is not a mixture ratio of pigment to TPU or a mixture ratio of glass bead to TPU, but the method for manufacturing the multi-layer sheet by extruding at least two raw materials at a time, and the multi-layer sheet using the method. Thus, the present invention should not be limited to the mixture ratio provided below. However, if the pigment and the TPU are mixed or the glass bead and the TPU are mixed on the basis of the mixture ratio provided below, the best effect (high definition, high quality, and high brightness) can be embodied.

A preferred embodiment of the present invention will be in detail described with reference to the accompanying drawings below. FIG. 1 sequentially illustrates the method for manufacturing the multi-layer sheet having the color TPU layer and an uppermost embossing according to a preferred embodiment of the present invention. In the manufacturing method of the present invention, two or more compositions are extruded at a time using a co-extrusion (3 layer T-die) method, thereby manufacturing a multi-layer sheet comprised of the color TPU layer and the resin layer, a multi-layer sheet comprised of the color TPU layer and the glass bead layer, or a multi-layer sheet comprised of the color TPU layer, the glass bead layer, and the resin layer. This manufacturing method is comprised of a process of mixing the pigment with the TPU (or a process of mixing the glass bead and the TPU) , a process of co-extruding three (or two) compositions, and a process of embossing a surface according to need.

Referring to FIG. 1, when the multi-layer sheet is manufactured, a first raw liquid Ia and a second raw liquid 2a are to form the resin layer besides the color TPU layer. In general, they employ resin series liquid. In the present invention, they employ TPU, polyurethane, polyolefin, and hot melt among the resin series liquid, and employ a mixture liquid of the glass bead and the TPU (Hereinafter, referred to as "glass bead and TPU mixture liquid") according to need.

In other words, as shown in FIGS. 3A to 3D, when the multi-layer sheet comprised of two or three layers is manufactured, a layer other than the color TPU layer is formed of the first raw liquid Ia and the second raw liquid

2a. The first and second raw liquids Ia and 2a employ any one resin of the TPU, the polyurethane, the polyolefin, and the hot melt described above. As shown in FIGS. 4A to 4C, when one layer is to form the color TPU layer and the other layer is to form the glass bead layer, the first raw liquid Ia employs the glass bead and TPU mixture liquid, and the second raw liquid 2a employs any one resin of the TPU, the polyurethane, the polyolefin, and the hot melt. The first and second raw liquids Ia and 2a can be exchanged with each other.

A pigment and TPU mixture liquid 3a is a step of embodying various colors on a surface of the multi-layer sheet even without screen printing or printing work, and constitutes the color TPU layer as shown in FIGS. 3 and 4. The color TPU layer has various colors such as white, silver, indigo, and yellow.

Mixing 3b is a step of mixing the pigment with the TPU at a constant ratio and then, agitating them at a room temperature. There are two methods in mixing the pigment with the TPU: a first method is employed at the time of using powder and a second method is employed at the time of using a master batch. The mixture ratio of the pigment to the TPU is shown in Tables 1 and 2 in detail. The mixing 3b step is applied even when the glass bead and the TPU are mixed at a constant ratio. Its mixture ratio is 1,00Og of the TPU to lOOg to 15Og of the glass bead (in the case of the master batch) . Table 1 In use of powder

Table 2

In use of master batch

Pearl Navy

TPU(85A) ^!l,000g

30% Pearl

|70~90g

Ultra Blue

30% White

,10~25g

Pearl 111 |

10% Black |0.5~2.5g

I t -

10% Violetjl00~200g

Screw transferring Ib, 2b, and 3c, and extruding (Ic, 2c, 3d) are steps of extruding the first and second raw liquids Ia and 2a and the mixed mixture liquid 3a (mixture liquid of the glass bead and the TPU) at a constant speed, and transferring them toward a dice 10. Dice passing 3e is a step of discharging three raw liquids (preferably, the first raw liquid Ia, the second raw liquid 2a, and the pigment and TPU mixture liquid 3a) at a speed of 22 rpm to 41 rpm. If the dice passing 3e step is performed, the multi-layer sheet in which three layers are integrally formed (that is, non-embossed multi-layer sheet) is manufactured.

Roller passing 3f and embossing forming 3g are steps of embossing the surface of the multi-layer sheet comprised of the three layers passing 3e through the dice 10. Such steps 3e and 3f will be easily understood in a detailed description of FIG. 2.

As shown in FIG. 2, the first and second raw liquids Ia and 2a and the mixed mixture liquid 3a are introduced into the dice 10, extruded at a time through the dice 10, and discharged while forming the three layers. According to need, the mixture liquid of the glass bead and the TPU can be supplied to the dice 10.

A cushion roller 12, a un-gloss treated roller, is generally manufactured using a silicon material. The cushion roller 12 serves to move the multi-layer sheet (non-embossed sheet) comprised of the three layers extruded through the dice 10, toward an embossing roller 14. The embossing roller 14 is formed of steel material, and has a protrusion and depression 14 whose surface is corrosion treated. According to this structure, the multi-layer sheet is embossed on its surface. A steel roller 16, a gloss roller, serves to transfer the completed multi-layer sheet.

A detailed description will be made on the basis of a preferred embodiment of the present invention below, and does not limit the present invention. First, the method for manufacturing the multi-layer sheet will be in detail described, as one example, in a first embodiment of the present invention, and a construction of the multi-layer sheet manufactured using the method according to the first embodiment will be in detail described in other embodiments (second to eighth embodiments).

First Embodiment A method for manufacturing a multi-layer sheet comprised of three layers will be described in a first embodiment of the present invention. In detail, the method for manufacturing the multi-layer sheet having a hot melt rein layer formed as a lowermost layer, a polyurethane resin layer formed thereon, and a color TPU layer formed thereon as shown m FIG. 3C will be described.

Three chambers are prepared, and each chamber is filled with first and second raw liquids Ia and 2a and pigment and TPU mixture liquid 3a. In other words, two chambers are filled with hot melt and polyurethane liquids, respectively, and remaining one chamber is filled with pigment and TPU and they are mixed as shown in the Tables 1 and 2.

After that, the pigment and the TPU are mixed 3b by an agitator and then, are transferred 3c toward the dice 10 while being extruded 3d. At the same time, the hot melt and polyurethane liquids filled in the chambers, respectively, are transferred Ib and 2b toward the dice 10 while extruded Ic and 2c, respectively.

Next, the hot melt and polyurethane liquids and the TPU liquid (pigment mixed TPU liquid) are three-layered

(Hereinafter, referred to as "semi-product"), respectively, while discharged toward the cushion roller 12. In other words, the hot melt resin layer is formed as the lowermost layer, the polyurethane resin layer is formed as a middle layer, and the color TPU layer (e.g., silver color layer) is formed as an uppermost layer.

After that, the semi-product passes through the embossing roller 14 engaged with the cushion roller 12 and thus, is pressed toward the embossing roller 14 under a cushion force of the cushion roller 12. As a result, the color TPU layer is embossed on its surface by the embossing 14a of the embossing roller 14 and then, is wound on a winding roll (not shown) using the steel roller 16 (Referring to FIG. 3C) .

The multi-layer sheet manufactured as above has the embossing, such as various designs or patterns, and the color

TPU layer based on various colors as shown in FIG. 3C, even without the separate printing process and without using the patterned release paper.

Second Embodiment

Any one resin selected from TPU, polyurethane, polyolefin, and hot melt is filled in a chamber, and pigment (e.g., silver-color pigment) and the TPU are filled and mixed in a chamber. And then, they are extruded at a time in the co-extrusion process shown in FIG. 1, thereby manufacturing a two-layered sheet as shown in FIG. 3A.

In other words, as shown in FIG. 3A, a resin layer is formed as a lowermost layer, and a color TPU layer is formed on the resin layer. If the two layered sheet passes through the embossing roller, the color TPU layer is embossed on its surface .

Third Embodiment

If an extrusion arrangement (sequence) is changed in the co-extrusion process described in the second embodiment, as shown in FIG. 3B, a color TPU layer is formed as a lowermost layer, and a transparent resin layer is formed thereon, thereby manufacturing a two-layered sheet. The transparent resin layer is formed using transparent resin such as TPU or polyolefin.

If the two-layered sheet passes through the embossing roller in the same manner as that of the first embodiment, the transparent resin layer is embossed on its surface. Fourth Embodiment

Resins of two kinds selected from TPU, polyurethane, polyolefin, and hot melt are filled in a chamber, respectively, and blue pigment and TPU are filled and mixed in a chamber. And then, they are extruded at a time by a co- extrusion process, thereby manufacturing a three-layered sheet as shown in FIG. 3C.

In the three-layered sheet manufactured as above, a hot melt resin layer is formed as a lowermost layer, a polyurethane resin layer is formed as a middle layer, and a blue colored color TPU layer is formed as an uppermost layer

(Referring to FIG. 3C) .

Next, if the three-layered sheet is subjected to the roller passing (3f) step of FIG. 1, the color TPU layer is embossed on its surface.

Fifth Embodiment

If an extrusion arrangement (sequence) is changed in the co-extrusion process of the fourth embodiment, as shown in FIG. 3D, a resin layer is formed as a lowermost layer, a color TPU layer is formed as a middle layer, a transparent resin layer is formed as an uppermost layer, and the transparent resin layer is embossed on its surface. The resin layer is formed using one resin selected from TPU, polyurethane, polyolefin, and hot melt, and the transparent resin layer is formed using transparent resin such as TPU or polyolefin.

Sixth Embodiment Glass bead and TPU are filled and mixed in a chamber, and pigment (e.g., white pigment) and TPU are filled and mixed in a chamber. And then, the mixture liquids are extruded at a time in the co-extrusion process shown in FIG. 1, thereby manufacturing a two-layered sheet having a glass bead layer as shown in FIG. 4A. As shown in FIG. 4A, a white color TPU layer is formed as a lowermost layer, and a glass bead layer of high brightness is formed thereon. If the two-layer sheet is subjected to the roller passing (3f) step shown in FIG. 1, the glass bead layer is embossed on its surface.

Seventh Embodiment

One resin (e.g., polyurethane) selected from TPU, polyurethane, polyolefin, and hot melt is filled in a chamber, and glass bead and TPU are filled and mixed in a chamber, and white pigment and TPU are filled and mixed in a chamber .

After that, if the resin and each mixture liquid are extruded at a time in the co-extrusion process of the present invention, as shown in FIG. 4B, a polyurethane resin layer is formed as a lowermost layer, and a white color TPU layer is formed as a middle layer, and a glass bead layer of high brightness is formed as an uppermost layer.

Next, if a three-layered sheet as above is subjected to the roller passing (3f) step shown in FIG. 1, the glass bead layer is embossed on its surface.

Eighth Embodiment

If an extrusion arrangement is changed in the co- extrusion process described in the seventh embodiment, as shown in FIG. 4C, a color TPU layer is formed as a lowermost layer, and a glass bead layer is formed thereon, and a transparent resin layer is formed as an uppermost layer. The transparent resin layer uses transparent resin such as TPU or polyolefin. If a three-layered sheet constructed as above is subjected to the roller passing (3f) step of FIG. 1, the transparent resin layer is embossed on its surface.

If the uppermost layer is peeled off by a laser work from the multi-layer sheet manufactured in the above method, preferably, if the uppermost layer is partially removed by the laser work from the multi-layer sheet of FIG. 3B, the multi-layer sheet of FIG. 3D, and the multi-layer sheet of FIG. 4C, the color TPU layer is exposed at a peel-off place.

In other words, as shown in FIG. 5, in the multi-layer sheet in which the resin layer is formed as the lowermost layer, and the color TPU layer is formed thereon, and the resin layer is formed as the uppermost layer, an uppermost layer surface is peeled off by the laser work. If so, as shown in FIG. 6, the color TPU layer (a character of "TM" is a color TPU layer portion in the drawings) is exposed only at the peel-off place, and the remnant layer remains as it is at remaining portions.

Industrial Applicability

As described above, in the present invention, color can be embodied at the time of an extrusion process without a printing work (or screen printing work) , thereby removing a VOC regulation material of a printing ink, and reducing printing cost and time and a product cost. In addition, extrusion can be performed at a time without a bonding process, thereby manufacturing a multi-layer TPU sheet. Thus, there is an advantage that a work process and a work time can be reduced, and a use of an adhesive is not required at all.

In particular, the present invention has an effect that the multi-layer sheet is improved in quality and a high- frequency cutting power is not only improved but also a physical property of TPU itself is kept and a color quality and a sheet surface (cosmetic) get better. While the present invention has been described and illustrated herein with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention that come within the scope of the appended claims and their equivalents .

Claims

1. A method for manufacturing a multi-layer sheet with a color TPU (thermoplastic polyurethane) layer, the method comprising steps of: mixing thermoplastic polyurethane with pigment, and preparing a resin series composition; and extruding the mixture liquid and resin at a time in a co-extrusion process, and forming the colored color TPU layer and at least one resin layer formed of the resin.

2. A method for manufacturing a multi-layer sheet with a color TPU layer, the method comprising steps of: mixing thermoplastic polyurethane with glass bead, mixing thermoplastic polyurethane with pigment, and selectively preparing a resin series composition; and extruding each mixture liquid and the selective resin at a time in a co-extrusion process, and selectively forming a glass bead layer and the colored color TPU layer or a resin layer.

3. The method according to claim 1 or 2, further comprising a step of forming an embossing on a surface of an uppermost layer of the multi-layer sheet.

4. The method according to claim 1 or 2, further comprising a step of partially removing the surface of the uppermost layer of the multi-layer sheet.

5. The method according to claim 1 or 2, wherein the resin series is thermoplastic polyurethane or polyolefin or polyurethane or hot melt.

6. A multi-layer sheet manufactured by a method claimed in any one of claims 1 to 5

7. A multi-layer sheet, comprised of at least one resin layer and a color TPU layer that are formed by co- extruding thermoplastic polyurethane liquid which is a mixture of resin and pigment.

8. A multi-layer sheet, comprised of a glass bead layer and a color TPU layer that are formed by co-extruding thermoplastic polyurethane mixed with glass bead and thermoplastic polyurethane liquid mixed with pigment.

9. The multi-layer sheet according to claim 8, further comprising a resin layer.

10. The multi-layer sheet according to any one of claims 7 to 9, wherein an embossing is formed at an uppermost layer of the multi-layer sheet.