Embossed suede material and method of preparing same

An embossed plastic suede material is prepared by the method of embossing under heat and pressure particular areas of a layer of a cellular plastic material characterized by a suede-like surface to provide an embossed surface composed of valley areas and peak areas, the peak areas characterized by a suede-like surface, the cellular structure beneath the valley areas differing from the cellular structure beneath the peak areas and characterized by a higher cell density.

BACKGROUND OF THE INVENTION 
Plastic material having a suede-like surface has been prepared by a number 
of techniques. One process employed to prepare commercial imitation suede 
material comprises the mechanical abrasion of the surface of a supported 
cellular plastic layer (see U.S. Pat. No. 3,041,193). Another process 
comprises delaminating a cellular plastic layer along a section of the 
cellular layer, such as along a plane of tensile discontinuity between two 
foam layers, or by creating a plane of tensile continuity through 
employing a temperature gradient, or by the compounding of resins within a 
particular foam layer. This latter process is described more particularly 
in U.S. Pat. No. 3,709,752, issued Jan. 9, 1973, the disclosure of which 
is hereby incorporated by reference in its entirety into this application. 
Although these and other processes have been employed to provide a 
suede-like material suitable for use in belts, handbags, shoes and 
articles of apparel, such as coats, vests, jackets, etc., such techniques 
do not provide for the preparation of suede material in an easy, efficient 
and economical manner, which material has an embossed surface design 
thereon. A plastic material which has, in whole or in part, a suede-like 
surface and which also has an embossed design thereon, and is produced in 
an efficient and economic manner, would be quite useful to provide 
different design patterns and material, such as, for example, imitation 
cordurory-like material. 
SUMMARY OF THE INVENTION 
Our invention concerns an improved suede-like material composed of a layer 
of cellular plastic having both a suede-like surface thereon and an 
embossed surface thereon, and the method of preparing such materials. In 
particular, our invention relates to an embossed suede-like plastic 
material comprising a layer of cellular plastic composed of valley and 
peak areas and a predetermined surface design thereon, with the peak areas 
having a suede-like surface, and with the density of the cells beneath the 
valley areas being greater than the density of the cells beneath the peak 
areas. 
We have discovered a method of preparing a unique embossed suede-like 
plastic material, which method comprises embossing under heat and pressure 
particular areas of a layer of a cellular plastic material characterized 
by a suede-like surface thereon. The embossing step is carried out to 
provide an embossed surface in the layer of the wholly cellular plastic 
composed of valley areas and peak areas which represent the indentations 
and compressions of the cellular layer made by the embossing roll or 
plate. In our technique, the peak areas of the resulting suede-like 
material are characterized by the original suede-like surface, so that the 
cellular structure beneath the peak areas is essentially the cellular 
structure prior to the embossing step. 
The valley areas differ in cellular structure and cell density beneath the 
valley areas due to the compression of the areas in the embossing step. 
The valley areas are, therefore, characterized by a slightly compressed 
cell-type structure, such as an oval-type cell, and/or of a higher cell 
density directly beneath the valley areas. For example, the cell density 
of the cells of the plastic layer directly beneath the valley areas may be 
from about 50 to 200% greater in cell density than the cell density 
beneath the peak areas. Of course, the change of density is related to the 
amount of pressure and heat employed in the embossing step, and may be 
varied as desired. However, the heat and pressure employed in the 
embossing step should not be sufficient to change the cellular layer such 
as to compress completely and destroy substantially the cells which would 
change the area beneath the valley areas into a solid, less flexible 
layer. 
By employing an embossing step such that the cellular nature of the layer 
of cellular plastic is retained, the suede-like material, supported or 
unsupported, continues to be very flexible like natural suede, while 
unusual design and imitative surface effects can be obtained. Of course, 
it is also part of our invention that the suede-like surface material may 
have a number of varying peak and valley areas of differing height in 
order to impart varying design effects, so that the cell density and cell 
structure beneath each area would vary, depending upon the embossing step, 
the nature of the plastic and the original nature of the cellular 
structure; that is, whether open or closed and cell size. 
In our process, the suede-like material to be embossed may comprise any 
suede-like material which is composed of a layer of a cellular plastic 
having a suede-like surface appearance. Typically, the suede-like sheet 
material would comprise a fibrous material, such as a woven fabric like 
cotton fabric, having secured thereto a layer of cellular plastic with the 
suede-like surface appearance. The plastic can typically be composed of 
any plastic or polymeric material or resin which is capable of forming a 
cellular layer and which is thermoplastic when subject to deformation 
during the embossing step. However, the preferred material is a 
vinyl-halide resin, such as polyvinyl chloride and 
vinyl-chloride/vinyl-acetate resins and similar types of vinyl-chloride 
resins which are plasticized and cast or formed onto a supporting sheet. 
During the embossing step, the valley areas produced by the embossing are 
altered in appearance and are less or nonsuede-like in appearance after 
such embossing; therefore, providing a contrast between the raised 
suede-like surface of the peak areas and the nonsuede-like or smoother 
embossed surface of the valley areas. Of course, if desired, the valley or 
peak areas, or both, may be coated or printed to accentuate the 
differences between the two areas to provide unusual design effects. 
In our process, the type and character of the embossing plate or roll used 
may not have all of the mechanical supports and requirements of typical 
embossing rolls and plates, since the embossing is done under very little 
pressure; i.e., merely sufficient pressure to compress the valley areas of 
a layer of cellular foam, if cellular foam under heat is thermoplastic, so 
that the pressure may be little more than contacting pressure in 
comparison to typical embossing operations where much higher pressure and 
heat are required. For example, the usual steel-engraved embossing roll 
may be employed or a design placed on the surface of a hard rubber roll. 
Our technique will be described in particular as an improvement of the 
processes and products described in U.S. Pat. No. 3,709,752 wherein a 
suede-like plastic material is made with a cellular surface composed of an 
undulating, irregular surface composed of tensile-ruptured cells with 
short plastic fibrils on the surface thereof, but which provides for a 
surface having a suede-like appearance of or approaching that of natural 
suede leather.

DESCRIPTION OF THE EMBODIMENTS 
FIG. 2 shows a prior art cellular laminate, such as the type employed in 
the process described in U.S. Pat. No. 3,709,752, to produce a suede-like 
plastic material, with a suede surface composed essentially of 
tensile-ruptured cells, which material 10 comprises a woven fabric 
supporting sheet 12, a solid plasticized vinyl-chloride resin layer 14, a 
cellular vinyl-chloride resin layer 16 and a thinner cellular 
vinyl-chloride resin layer 18 and a paper sheet 20 bonded to resin layer 
18. 
In FIG. 1, the laminate sheet material 10 is introduced by a pair of 
opposing rollers 50 and 52 into contact with the surface of a large 
steam-heated roller 56 heated, for example, to a temperature of 
250.degree. to 350.degree. F. The woven fabric 12 side is placed against 
the surface of and is passed around drum 56. Infrared heaters 54 direct 
infrared heat to the external surface of paper sheet 20. The paper sheet 
20 and a portion of the resin layer 18 adhering thereto is stripped or 
delaminated from the remaining portion of the laminating material 10 in 
the stripping or delaminating area 60. The paper sheet 20 with layer 18 
containing a tensile-ruptured cell surface thereon moves by roller 58 to 
form roll 62. If desired, the paper substrate can be replaced by a fibrous 
substrate as woven sheet 12, and then embossed in the manner set forth 
hereafter to provide an embossed paper or fabric-supported product as 
described. 
The stripping and delaminating operation provides a plane of tensile 
discontinuity in the resin layers 16 and 18, and also provides a 
tensile-ruptured suede surface on layer 16 which gives it a suede-like 
appearance, as well as a suede-like surface on layer 18 on sheet 20. 
The woven fabric 12, solid layer 14 and the cellular layer 16 with the 
tensile-ruptured surface is then embossed on embossing roller 66 which 
lightly contacts the hot suede-like surface of the cellular layer 16 to 
impart a design effect thereon and to create raised peak areas and lower 
valley areas in the suede-like cellular layer. A printing roller 68 and 
printing ink 70 are employed in order to place within the embossed valley 
areas a layer of printing ink to enhance the embossed appearance of the 
finished article. The suede-like article so embossed is then removed 
through roller 72 and is shown as a finished embossed material 30. At the 
time of embossing, the surface of the fabric is typically at about 
275.degree. to 300.degree. F, with the external paper surface at a lower 
temperature of about 250.degree. to 270.degree. F. The cellular layer 16 
is adapted to be compressed easily by the design on the embossing roller 
66, but little, if any, pressure is required in the embossing step. In the 
embossing step as illustrated, the embossing roller creates the valley 
areas, but does not apply any pressure to the raised peak areas, leaving 
these areas with the original suede-like surface, while compressing the 
cellular layer in the areas beneath the valley areas to form a smooth 
surface of continuous vinyl resin as a skin layer. 
FIG. 3 shows an embossed suede-like material 30 prepared by our process and 
includes the woven fabric 12, a solid vinyl-chloride plasticized layer 14 
and peak surface areas 32 having a tensile-ruptured suede-like surface 
appearance thereon, and valley areas 36, with the thickness between the 
peak and valley areas shown as 34. In the valley areas, there is a 
printing ink layer 38 which may be colored or clear. The cellular 
structure and cell density directly beneath the peak areas 32 are in their 
substantially original form of relatively uniform cell structure and 
original cell density as in the preparation of the cellular layer prior to 
embossing. The cellular structure and cell density of the cells 42 
directly beneath the valley areas 36 are different from the cell structure 
and density 40 beneath the peak areas in that such areas, although still 
cellular, which is important to preserve the flexible nature of our 
material, have cells which are partially collapsed or compressed due to 
the embossing step, and also contain a greater cell density than the cell 
density in the areas 40. 
The difference in cell density and cell structure, however, does not affect 
the overall flexibility of the sheet material as might be the case where 
complete compression and destruction of the cellular areas took place, and 
a solid layer was formed. In this embodiment illustrated, the embossing 
roll has been designed to impart an embossed cordurory effect on sheet 
material 20. However, it is recognized that a number of designs may be 
imparted to the suede-like material to provide various raised peak areas 
of textured surface throughout the material, such as for the preparation 
of wall or surface coverings. 
Our process has also been illustrated with the use of an embossing roller; 
however, embossing plates or other methods of forming the valley areas and 
the hot layer of the cellular plastic of the suede-like surface may be 
used. When using rollers as illustrated or plates, since the fabric or 
supported sheet side of the suede-like material is at a high temperature, 
the embossing roll should be maintained at a lower temperature in order to 
prevent sticking and pulling away of the cellular layer of plastic to the 
embossing roll. Where another layer of cellular plastic which has a 
suede-like surface is employed, such as a mechanically abraded surface, 
the stripping and delaminating steps may be omitted and the material 
merely passed about a drum and heated prior to the embossing step. 
As illustrated, a variety of embossing designs may be imparted to the suede 
material. If desired, the suede material may be prepared in any manner, 
stored for a period of time and susequently embossed by reheating the 
material and passing it through embossing rollers, although it is 
preferred, for economic reasons, to carry out the stripping operation and 
subsequent embossing step in sequence. If desired, the paper sheet 62 or a 
similarly produced fabric sheet as described from the stripping step may 
be processed by embossing the suede-like surface of the paper or fabric 
sheet after the stripping step. Such embossing may be carried out by the 
use of an additional steam roller 56 and embossing rollers 66, rather than 
winding up the material in a roll as illustrated. Thus, from the laminate 
sheet 10, one or two supported embossed suede-like surfaces may be 
obtained. 
For the purposes of illustration, the embossed material has been shown as a 
supported thermoplastic material with paper and fabric sheet materials. 
However, any sheet substrate material may be used and bonded to the single 
and multiple-layer foam sheet to be delaminated. In addition, the suede 
material may be passed under heat and contacting pressure through a series 
of embossing rollers to produce a variety of surface design effects with 
valley areas of different depth and structure. 
Other modifications and techniques will be apparent to those skilled in the 
art from our description and illustration of the invention.