DIMENSIONAL ENHANCEMENT OF ARTIFICIAL LEATHER POLYURETHANE COMPOSITE MATERIAL

Abstract

A composite material formed by combining a polyurethane material with an unclickable foam layer and a scrim layer through roll and flat form technology. The composite material is embossed to form pillowlike chambers or cells delineated by a network of emboss pattern lines formed by the bonding between these layers.

Claims

1. An embossed composite material, comprising: a polyurethane layer; an un-clickable foam layer having a top surface and an opposite bottom surface, wherein said top surface is bonded to said polyurethane layer; a backing that is bonded to said bottom surface of said un-clickable foam layer, wherein said polyurethane layer, said un-clickable foam layer and said backing each has an emboss pattern forming pillow-like cells, and wherein said pillow-like cells are delimited by emboss protuberances and emboss lines formed by said emboss pattern.

2. The embossed composite material as recited in claim 1, wherein said polyurethane layer includes a top surface layer, a skin layer bonded to said top surface layer, and a textile backing layer bonded to said skin layer with a binder layer.

3. The embossed composite material as recited in claim 2, wherein the combined weight of said top surface layer, said skin layer and said binder layer is between about 27% and about 30% of the total weight of the said polyurethane layer.

4. The embossed composite material as recited in claim 2, wherein said textile backing layer is made of circle knit fabric.

5. The embossed composite material as recited in claim 4, wherein said circle knit fabric is napped.

6. The embossed composite material as recited in claim 1, wherein said un-clickable foam layer is made of polyester polyurethane foam.

7. The embossed composite material as recited in claim 6, wherein said un-clickable foam layer has a thickness of between about 3 mm and about 5.2 mm.

8. The embossed composite material as recited in claim 1, wherein said emboss pattern of said polyurethane layer is substantially parallel to said emboss pattern of said top surface of said un-clickable foam layer, and wherein said emboss pattern of said backing is substantially parallel to said emboss pattern of said bottom surface of said un-clickable foam layer.

9. The embossed composite material as recited in claim 1, wherein said backing is a textile or nonwoven fabric layer.

10. A method for making an embossed composite material, comprising the steps of: providing a polyurethane layer, an un-clickable foam layer and a backing; combining said polyurethane layer, said un-clickable foam layer and said backing to form a composite material; embossing a pattern on said composite material to form an embossed composite material having pillow-like cells delimited by emboss protuberances and emboss lines formed by said pattern.

11. The method for making an embossed composite material as recited in claim 10, wherein said embossing step comprises the steps of: providing a roll embossing device having an embossing station; feeding said composite material to said embossing station, said embossing station having an engraved embossing roll adjacent to a receiving roll; and passing said composite material through the nip of said receiving roll and said embossing roll.

12. The method for making an embossed composite material as recited in claim 11, further comprising the step of heating said receiving roll and said engraved embossing roll, wherein said receiving roll is heated to a temperature higher than said engraved embossing roll.

13. The method for making an embossed composite material as recited in claim 11, further comprising the steps of: heating said receiving roll to temperature of about 190° C.; and heating said engraved embossing roll to a temperature of about 150° C., wherein said heating steps are before said composite material is passed through said nip.

14. The method for making an embossed composite material as recited in claim 11, further comprising the steps of: heating said receiving roll to temperature of between about 190° C. and about 195° C.; and heating said engraved embossing roll to temperature of between about 120° C. and about 180° C., wherein said heating steps are before said composite material is passed through said nip.

15. The method for making an embossed composite material as recited in claim 11, wherein said passing step is done at a line speed of between about 3 and about 5 yards per minute.

16. The method for making an embossed composite material as recited in claim 11, further comprising the steps of: providing a press roll adjacent to said engraved embossing roll; and pressing said engraved embossing roll towards said receiving roll to maintain a pressure between about 4 and about 8 MPa.

17. The method for making an embossed composite material as recited in claim 10, wherein said combining step is done by an open flame lamination process.

18. The method for making an embossed composite material as recited in claim 10, wherein said embossing step comprises the steps of: providing a flat embossing device having an embossing station; feeding said composite material to said embossing station, said embossing station having an upper engraved embossing plate and a lower flat plate; and pressing together said upper engraved embossing plate and said lower flat plate to form said pattern on said composite material.

19. The method for making an embossed composite material as recited in claim 18, further comprising the steps of: heating said upper engraved embossing plate to a temperature of about 190° C.; and heating said lower flat plate to a temperature of about 200° C., wherein said heating steps are before said pressing step.

20. The method for making an embossed composite material as recited in claim 18, wherein said pressing step is done for about 5 seconds to about 15 seconds of time.

21. The method for making an embossed composite material as recited in claim 18, further comprising applying pressure to said embossing station of between about 10 and about 30 psi.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0023] In the Drawings:

[0024] FIG. 1A is a perspective view of a section of embossed composite material according to an embodiment of the present invention;

[0025] FIG. 1B is a cross-sectional view of a section of embossed composite material according to an embodiment of the present invention;

[0026] FIG. 2 is a diagram illustrating a process for making an embossed composite material according to an embodiment of the present invention;

[0027] FIG. 3 is a cross-sectional view of a material used to make an embossed composite material according to an embodiment of the present invention;

[0028] FIG. 4 is a diagram showing a process for making an embossed composite material according to an embodiment of the present invention;

[0029] FIG. 5 is a cross-sectional view of a material used to make an embossed composite material according to an embodiment of the present invention;

[0030] FIG. 6 is a diagram of a process for making an embossed composite material according to an embodiment of the present invention;

[0031] FIG. 7 is a perspective view of an embossing device used to make an embossed composite material according to an embodiment of the present invention;

[0032] FIG. 8 is a perspective view of an embossing device used to make an embossed composite material according to an embodiment of the present invention;

[0033] FIG. 9 is a cross-sectional view of an embossed composite material according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Certain preferred embodiments and examples are disclosed herein. However, the inventive subject matter extends beyond the examples in the specifically disclosed embodiments to other alternative embodiments and/or uses, and to modifications and equivalents thereof. Thus, the scope of the claims below is not limited by any of the particular embodiments described herein. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in a manner or order that may be helpful in understanding certain embodiments; however, the order of description should not be understood to imply that these operations are order-dependent. Additionally, the structures, systems, and/or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various embodiments, certain aspects and advantages of these embodiments are described. Not necessarily all such aspects or advantages are achieved by any particular embodiment. Thus, for example, various embodiments may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.

[0035] The present invention includes an embossed composite material and processes and devices for making an embossed composite material having the appearance and attributes of leather.

[0036] This invention allows for the dimensional enhancement of PU materials used to form synthetic leather. As used herein, the term “PU” refers to polyurethane containing or polyurethane coated materials. PU materials can be altered by a pattern or design. Here, the materials and processes used provide both two dimensional and a three dimensional aspect to the design of the final PU synthetic leather product.

[0037] An example of a dimensionally-enhanced PU leather 10 according to an embodiment of the present invention is illustrated in FIGS. 1A-1B. As illustrated, the PU leather 10 is embossed with a pattern that is decorative and three-dimensional in appearance. The pattern is defined by a network of markings or lines 12 and pillow-like cells 14 that are formed during the embossing process in which the material layers are bonded through heat and pressure at or along the bond lines 12.

[0038] A variety of patterns other than the one illustrated in FIGS. 1A and 1B are contemplated by the present invention. For example, the emboss patterns can be symmetrical or asymmetrical. The shapes of the pillow-like cells 14 can be geometric or random. The dimensions of the bond lines 12 and pillow-like cells 14 can also be consistent or inconsistent. The term “lines” is used to describe any marking or visible impression indicating the area in which the composite material layers are bonded or melted together in relation to the corresponding engraving on the emboss device used. A wide variety of pattern designs can be used to form the present PU leather material provided that the emboss pattern is suitable for maintaining the bonding between the composite materials and thus the integrity of the pillow-like cells.

[0039] Different materials used to form the PU leather 10 contribute to the effectiveness of embossing to impart a three-dimensional pattern that is maintainable after use in a final product, such as in an automobile seat. In FIG. 1B, a cross-sectional view of one embodiment of the PU leather 10 that illustrates different materials used to form the composite material include a PU face material 20, a foam material 22, and a scrim material 24. Each of these materials includes one or more layers that are combined by devices and processes described here.

[0040] In one embodiment, the PU face material 20 is formed by a process illustrated in the FIG. 2 diagram. Release paper 30 is provided through a leading roll 32 and fed through a series of curing chambers where coatings are introduced. At a first curing chamber 34, the release paper 30 is coated with an amount of water-based PU that is cured (dried and solidified) to form the PU surface layer. At a second curing chamber 40, the coated release paper 30 is further coated with an amount of PU resin 38 made of polycarbonate diols with an aliphatic isocyanate group to form the PU skin layer, which serves as the grain transfer in relation to the release paper. At a third curing chamber 42, the release paper 30 is further coated with an amount of PU adhesive resin 44 made of polycarbonate diols with an aliphatic group to serve as the PU binder layer. Through this process a surface layer of PU is formed on the release paper. Next, a backing material 48 is introduced and laminated to the surface of the coated release paper 30 through the use of rolls 50. Finally, the release paper is removed (not illustrated) to obtain the PU face material 20.

[0041] In FIG. 3, a cross-section of one embodiment of the PU face material 20 of the present invention is illustrated. These include the PU surface layer 60, the PU skin layer 62, the PU binder layer 64, and the backing layer 66.

[0042] Alternative embodiments of the PU face material 20 are contemplated by the present invention. For example, the PU skin layer 62 can be two layers rather than a single layer. In another embodiment, the PU skin layer 62 can be the top layer, substituting the surface layer 60 illustrated in FIG. 3. Additionally, a silicone layer (not illustrated) can be included between the PU skin layer 62 and the backing layer 66. Also, if the PU face material includes perforations (not illustrated), multiple skin layers having distinct colors can be used such that the color of an inner skin layer is different and visible through the perforations of an outer skin layer.

[0043] The proportions by weight and thickness of each layer of the PU face material 20 can also vary. In one embodiment, the surface layer 60, the skin layer 62, and the binder layer 64 together account for about 30% of the total weight of the PU face material 20, leaving the remainder of the weight attributed to the backing layer. In another embodiment, these three layers may be between about 27% and about 30% of the total weight of the PU face material 20, leaving the remainder of the weight attributed to the backing layer. In yet another embodiment, these three layers together may weigh about 120 g/m2 and the backing layer may weigh about 320 g/m2.

[0044] The simulation of the appearance of leather is achievable in part by the grain pattern on the surface of the release paper 30, which grain pattern becomes transferred to surface of the PU face material 20. A wide variety of grain patterns are available, including smooth, course, and technical (having repeating designs and shapes). The PU face material can further be perforated. Additionally, the PU face material 20 can be a wide variety of colors that are imparted through one or more dyes introduced during processing.

[0045] The material used for the backing layer 66 can also vary. The particular backing material provides thickness, tensile strength, and stretch properties to the PU face material. In one embodiment, the backing can be a circular knit textile. The circular knit textile can be flat or napped. These types of textiles provide enhanced trimability to the PU face material. The napped version of the circular knit can also enhance the haptic features of the PU face material. The use of tricot suede textile is also contemplated, especially if the PU face material is to be perforated. The backing can also be a nonwoven material, including nonwoven suede. Other materials could be suitable provided the backing is adapted to bind the surface of the foam material 22, as later described

[0046] To form the PU composite material that is to be embossed according to the present invention, the PU face material 20 is combined with the foam material and a scrim backing. In one embodiment, the PU composite material is formed by a process illustrated in the FIG. 4 diagram. This process includes open flame lamination through a series of three adjacent rolls, which are turned in opposing directions, with the middle roll turning in the reverse direction of the outer rolls. First, a foam material 70 is provided and directed to a first roll 72. As the foam material 70 passes around the first roll 72, a first open flame 74 melts the foam material 70 to create a tacky surface. Next, PU face material 20 is provided and directed to a second roll 76 next to the first roll 72. The bottom surface or backing side of the PU face material 20 bonds to the tacky surface of foam material 70 as they are squeezed between the nip of the first and second rolls 72, 76. As the bonded side of the foam material 70 is in contact with the second roll 76, the non-bonded or opposing side of the foam material 70 is melted by a second open flame 82 to create a tacky surface. Lastly, scrim or fabric backing 78 is provided and directed to a third roll 80 next to the second roll 76. The scrim backing 78 bonds to the non-bonded, tacky surface of foam material 70 as they are squeezed between the nip of the second and third rolls 76, 80 to produce a composite material 26 for embossing.

[0047] In an alternative embodiment (not show), the lamination of the foam layer and the scrim layer can be done in two separate passes, as opposed to a continuous process illustrated in FIG. 4.

[0048] A cross-section of one embodiment of the PU composite material 26 formed is illustrated in FIG. 5. In addition to the PU face layer, which in this embodiment includes a surface layer 60, a skin layer 62, a binder layer 64 and a backing layer 66, the composite material also includes a foam layer 70 and a scrim or fabric layer 78. This composite material 26 is used to make one embodiment of the embossed composite material 10.

[0049] The materials used for these additional layers provide enhanced properties to the composite material. In particular, the use of an un-clickable foam is a preferred material for the foam layer 70. “Clickable” foam resumes its afore-shape after being cut by a blade or punched by a die, or heated, so it is not suitable for embossing. As used herein “un-clickable” foam is a foamed material that is adapted for embossing that does not recover from a die cutting/embossing operation, thus maintaining its embossed shape. This un-clickable foam enables the embossment to be held in place permanently to give the three-dimensional effect desired in the present invention.

[0050] In one embodiment the foam layer 70 is polyester polyurethane that is between about 3 mm and about 5.2 mm in thickness. To achieve bonding between the foam and the outer PU face and scrim layers, the foam is preferably heated to melt on both sides, such as previously described. In the melting process according to one embodiment of the present invention, the foam thickness is reduced by about 1 mm on either side. Thus, the starting foam material 70 in this process should be between about 5 mm and about 7.2 mm to achieve a final foam thickness of between about 3 mm and 5.2 mm in the composite material. Other thicknesses are contemplated provided the foam layer effectively maintains the embossing pattern, as later described.

[0051] In another embodiment, the foam material may be a polyester polyurethane foam made commercially available by Foamex Innovations, International and designated as LC 160035. In another embodiment, the polyester polyurethane form may be commercially available from Foamex Innovations and designated as LZ185040. In still another embodiment the foam may have the following properties: an apparent density of about 1.85 lb/ft.sup.3, a cell count of about 75 CPI, and an indentation force deflection of about 65 lb/50″.sup.2. In yet another embodiment, the foam may have the following property ranges.

TABLE-US-00001 US CUSTOMARY UNITS MIN MAX DENSITY, APPARENT 1.50 2.50 LB/FT.sup.3 (kg/M.sup.3) INDENTATION FORCE DEFLECTION* 20.00 70.00 25% DEFL, LB/50″.sup.2 (N/323 cm.sup.2) CELL COUNT 42.00 80.00 CPI (CELLS/100 MM)

[0052] The textile or nonwoven scrim layer 72 provides protection from the heat of the embossing plates and rollers and dimensional stability to the product can be modified through scrim selection.

[0053] The embossing pattern of the PU composite material may be achieved through roll or flat embossing processes. One embodiment of a roll embossing process according the present invention is illustrated in FIGS. 6-7. First the PU composite material is provided through a leading roll 90 and taken up by the emboss roll device. Tension of the composite material is maintained through one or more bars 92 as the composite material is fed to the embossing station 94. The embossing station 94 includes three adjacent rolls, with an engraved embossing roll 100 in between heated receiving roll 96 and a press roll 106. The composite material 26 is introduced into the nip of the heated receiving roll 96 and the heated embossing roll 100, with the PU face 20 side of the composite material 26 making contact with the embossing roll 100 and the backing 24 side of the composite material 26 making contact with the heated receiving roll 96. The press roll 106 contributes to the tightness of the nip between the embossing roll 100 and the receiving roll 96. As the composite material runs between the embossing roll 100 and the receiving roll 96, the heat and pressure provided at the embossing station imparts an embossing pattern to the composite material. The embossed composite material 102 is then taken up at the winder 104 for use in various applications.

[0054] The heating, pressure and tension parameters contribute to the effectiveness of the roll embossing process and to the dimensional stability of the resulting embossed composite material. In one embodiment, the temperature of the engraved emboss roller 100 is not greater than about 140 degrees C./245 degrees F. In another embodiment, the temperature is about 120 degrees C./245 degrees F.

[0055] The materials used for the rolls can also vary. In one embodiment, the heated receiving roll 96 is made of metal. In another embodiment, the heated roll 96 is made of steel. In yet another embodiment, the temperature of the heated roll 96 is not greater than about 190 degrees C./375 degrees F. In another embodiment, the press roll 106 is made of a nylon material.

[0056] The dwell time at the contact point between the embossing roll 100, the composite material, and the heated receiving roll 96 is controlled by the line speed of the roll embossing machine. In one embodiment, the line speed is between about 3 and about 5 yards per minute. In one embodiment, the pressure was maintained between about 4 and about 8 MPa (megapascals).

[0057] Additionally, the engraved embossing rollers can create a variety of emboss designs. The patterns are engraved into the roller surface to precise depths and motif arrangement. In particular, the engraved embossing roll 100 includes an array of protrusions and recesses that are adapted for transfer a pattern on to the composite material 26. The dimensions of the protrusions and recesses can vary provided that the embossing pattern is transferred effectively through the composite material 26 without damaging the material.

[0058] One embodiment of a flat embossing process according the present invention is illustrated in FIG. 8. First the PU composite material is provided to the flat emboss device. The composite material 206 is directed to the embossing station 210 of a plate embosser. The embossing station includes a top engraved emboss plate 200 a receiving mat 202 and a heated bottom plate 204. The top emboss plate 200 is lowered onto the surface of the composite material. Alternatively, the top and bottom plates are pressed together. The heat and pressure applied at the embossing station results in an embossing pattern on the portion of composite material that is between the plates. The embossed composite material 208 is then moved out of the embossing station 210. Alternatively, the flat embossing is done through a continuous pass as opposed to embossing sections or portions of a composite material 206 sheet. Thus, the entire amount composite material, or only portions of the composite material can be embossed.

[0059] The heating, pressure and tension parameters contribute to the effectiveness of the flat embossing process and to the dimensional stability of the resulting embossed composite material. In one embodiment, the following parameters may be used for the plate embosser. The temperature of the emboss plate may be not greater than about 190 degrees C./380 degrees F. on the face of the plate touching the PU material. The temperature of the bottom heater plate may be not greater than about 200 degrees C./400 degrees F. on side touching the bottom scrim layer of the PU material. Dwell time varies by the emboss pattern to be used. In one embodiment, the dwell time may be between about 5 and about 15 seconds from the time the pressure control is engaged to when it is released. In another embodiment, the pressure used may be between about 10 and about 30 psi.

[0060] Additionally, the embossing plates can create a variety of emboss designs on the PU composite material. The patterns are engraved into metal material to precise depths and motif arrangement.

[0061] A cross-section of one embodiment the embossed composite material is illustrated in FIG. 9. As illustrated, emboss pattern is carried through the entire composite material. However, in view of the properties of the composite material, the PU face material layers and the top of the foam layer have similar curvatures, which appear to be mirror images of the curvatures of the bottom of the foam and scrim layers. As described, the embossing pattern forms pillow-like cells 14 that are delimited by the PU face and scrim protruberances 300, and contained within the bond lines 12.

[0062] Those skilled in the relevant arts will appreciate from the foregoing description of preferred embodiments that substitutions and modification can be made without departing from the spirit and scope of the invention which is defined by the appended claims.