U.S. patent application number 09/871344 was filed with the patent office on 2001-09-27 for absorbent sheet material having cut-resistant layer and method for making the same.
Invention is credited to Crawford, Albert Sylvester II, Hamilton, Peter Worthington, Hildebrand, Richard Emil IV, McGuire, Kenneth Stephen, Norcom, John David, Otten, Geneva Gail, Rhoads, Daniel James, Tweddell, Richard III.
Application Number | 20010024715 09/871344 |
Document ID | / |
Family ID | 26990236 |
Filed Date | 2001-09-27 |
United States Patent
Application |
20010024715 |
Kind Code |
A1 |
Otten, Geneva Gail ; et
al. |
September 27, 2001 |
Absorbent sheet material having cut-resistant layer and method for
making the same
Abstract
An absorbent and cut-resistant sheet having a cut-resistant
material with a plurality of openings, and an absorbent material
attached to the cut-resistant material. Preferably, the apertured
cut-resistant material is in the form of sheet having a thickness
of between about 0.005 inches and about 0.020 inches, and has an
open area of less than about 50 percent. It is also preferred that
the cut-resistant sheet have fold lines formed on a non-cutting
surface, so as to make the material easily foldable and/or
tearable. In addition, a stainable absorbent cover layer can be
attached to a cutting surface of the cut-resistant sheet to provide
an indication of where cutting has occurred, and to give the
material a desirable appearance. A liquid impervious backing layer
is also preferably attached to the absorbent material to resist the
escape of fluid from the absorbent material. It is preferred that
the cut-resistant sheet comprises a polymeric material.
Inventors: |
Otten, Geneva Gail;
(Cincinnati, OH) ; Crawford, Albert Sylvester II;
(Cincinnati, OH) ; Rhoads, Daniel James;
(Columbus, OH) ; Norcom, John David; (West
Chester, OH) ; Tweddell, Richard III; (Cincinnati,
OH) ; Hamilton, Peter Worthington; (Cincinnati,
OH) ; Hildebrand, Richard Emil IV; (West Chester,
OH) ; McGuire, Kenneth Stephen; (Wyoming,
OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
PATENT DIVISION
IVORYDALE TECHNICAL CENTER - BOX 474
5299 SPRING GROVE AVENUE
CINCINNATI
OH
45217
US
|
Family ID: |
26990236 |
Appl. No.: |
09/871344 |
Filed: |
May 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09871344 |
May 31, 2001 |
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09451884 |
Dec 1, 1999 |
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6274232 |
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Current U.S.
Class: |
428/315.9 ;
427/289 |
Current CPC
Class: |
B32B 2307/581 20130101;
B32B 3/266 20130101; B32B 2307/744 20130101; Y10T 428/24998
20150401; B32B 27/12 20130101; Y10T 428/24893 20150115; B32B
2307/7242 20130101; B32B 2307/7265 20130101; B32B 5/022
20130101 |
Class at
Publication: |
428/315.9 ;
427/289 |
International
Class: |
B32B 003/00 |
Claims
What is claimed is:
1. A cut-resistant and absorbent sheet, comprising: an absorbent
material; and a cut-resistant material attached to the absorbent
material, wherein the cut-resistant material has a plurality of
openings, and wherein the cut-resistant material has an open area
of less than about 50 percent.
2. The sheet as recited in claim 1, wherein the cut-resistant
material has a thickness of between about 0.005 inches and about
0.020 inches.
3. The sheet as recited in claim 1, wherein the cut-resistant
material has a lower surface attached to an upper surface of the
absorbent material and a substantially planar cutting surface
disposed opposite the lower surface.
4. The sheet as recited in claim 1, wherein the cut-resistant
material comprises a polymeric material.
5. The sheet as recited in claim 1, wherein the absorbent material
has a thickness of between about 0.005 inches and about 0.050
inches.
6. The sheet as recited in claim 1, wherein the cut-resistant
material has between about 10 and about 200 openings per square
inch.
7. The sheet as recited in claim 1, wherein the openings have a
maximum dimension of between about 0.010 inches and about 0.100
inches.
8. The sheet as recited in claim 1, wherein the sheet has a
plurality of fold lines formed therein.
9. The sheet as recited in claim 8, wherein the fold lines are
linear and have less resistance to tearing than the remainder of
the sheet.
10. The sheet as recited in claim 8, wherein the cut-resistant
material has a lower surface attached to an upper surface of the
absorbent material and a cutting surface disposed opposite the
lower surface, and wherein the fold lines are formed on the lower
surface of the cut-resistant material.
11. The sheet as recited in claim 1, wherein the cut-resistant
material has a lower surface attached to an upper surface of the
absorbent material and a cutting surface disposed opposite the
lower surface, and wherein the sheet further comprises: a cover
layer attached to the cutting surface.
12. The sheet as recited in claim 11, wherein the cover layer
comprises a fibrous material.
13. The sheet as recited in claim 1, further comprising: a liquid
impervious and skid resistant backing layer attached to the
absorbent material.
14. The sheet as recited in claim 1, wherein the sheet has a raised
edge along at least a portion of the periphery of the sheet.
15. The sheet as recited in claim 1, wherein the cut-resistant
material has a lower surface attached to an upper surface of the
absorbent material and a cutting surface disposed opposite the
lower surface, wherein the cutting surface has a non-glossy
appearance.
16. A method of forming a cut-resistant and absorbent sheet, the
method comprising the steps of: providing a cut-resistant layer
having a cutting surface and an opposing lower surface; forming
openings between the cutting surface and the lower surface of the
cut-resistant layer, wherein the total surface area of the openings
on the cutting surface is less than the remaining surface area of
the cutting surface; and attaching the lower surface of the
cut-resistant layer to an absorbent layer of material.
17. The method as recited in claim 16, further comprising the step
of: forming fold lines in at least one of the lower surface and
cutting surface of the cut-resistant layer.
18. The method as recited in claim 16, further comprising the step
of: attaching an absorbent cover layer to the cutting surface of
the cut-resistant layer.
19. The method as recited in claim 16, further comprising the step
of: attaching a liquid impervious backing layer to the absorbent
layer of material.
20. A sheet material comprising: an absorbent material; and a cut
resistant material attached to the absorbent material; wherein the
sheet material exhibits a slice resistance of at least about 30
kgf/cm, and wherein the sheet material will stain after contact
with liquid.
21. The sheet material as recited in claim 20, wherein the sheet
material exhibits an absorbent efficiency of at least about
0.2.
22. The sheet material as recited in claim 20, wherein the
cut-resistant material is translucent such as to allow staining in
the absorbent material to be seen through the cut-resistant
material.
23. The sheet material as recited in claim 20, wherein the
cut-resistant material has openings through which staining in the
absorbent material can be seen.
24. The sheet material as recited in claim 20, wherein the
cut-resistant material has oppositely disposed first and second
surfaces, wherein the absorbent material is attached to the first
surface, and wherein the sheet material further comprises: a
covering layer attached to the second surface of the cut-resistant
material, wherein the covering layer will stain after contact with
liquid.
25. The sheet material as recited in claim 24, wherein the covering
layer comprises a non-woven material.
Description
RELATED APPLICATION
[0001] This is a division of application Ser. No. 09/451,884, filed
on Dec. 1, 1999.
TECHNICAL FIELD
[0002] The present invention relates generally to cut-resistant,
flexible, and absorbent sheet materials. More specifically, in one
embodiment, the present invention relates to a sheet material
having a flat polymer upper layer having drainage openings and fold
lines, the upper sheet being bonded to a lower absorbent layer.
BACKGROUND OF THE INVENTION
[0003] Sheet materials having durability, such as those having
cut-resistance and shred resistance properties, are desirable for a
variety of applications. For instance, protective sheet materials
can be used in protecting countertops during food preparation. The
durability of the material prevents the cutting utensil from
damaging the counter top when preparing food items.
[0004] For convenience of use, it is also desirable that such
protective sheet materials be easily disposable. In this regard, it
is desirable that the sheet material have absorbent properties such
that juices from the food are well contained, thereby facilitating
clean-up following the food preparation operations. In addition,
the ability to visibly stain in the presence of colored food
effluent is desired, such that a stain will occur after cutting, to
indicate to the user that the sheet has already been used.
[0005] Moreover, it is desirable that the sheet material be easily
folded or collapsed to facilitate placement and storage of the
sheet material in a trash container following usage. In areas where
trash space is limited, the ability to fold the sheet material and
to keep it folded is even more important. Moreover, flexibility and
conformability of the sheet material allows it to be more easily
stored, dispensed, and manipulated during usage.
[0006] However, typical protective materials, such as polymer
materials for example, are not very absorbent, and in fact are
often hydrophobic. Accordingly, such materials typically do not
absorb fluids well, nor provide a stain indication of where cutting
has occurred. Moreover, such materials, when provided in adequate
thickness to provide cut resistance and protect surfaces, are
typically resilient in nature and so do not easily fold. Thus, they
are typically not readily foldable for ease of placement in a trash
container.
[0007] Additionally, obtaining the correct sheet size suited for
the task is desirable. The sheet is preferably large enough for big
tasks and yet also readily dividable into smaller sheets for
smaller tasks, thereby reducing product waste.
[0008] Accordingly, it is desirable to provide a unitary sheet
material with multiple diverse properties, such as cut and abrasion
resistance, shred resistance, use indication, absorbency,
flexibility, and/or ability to be divided into the desired sheet
size. It is also desirable to provide a sheet material which
includes a substantially smooth cutting surface, such that food
items can be easily cut on the material without interference from
grooves or other structures. It is further desirable to provide
such a material which may be readily and economically
manufactured.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to obviate the
above-described problems.
[0010] Another object of the present invention is to provide a
disposable and protective cutting sheet with a substantially smooth
cutting surface.
[0011] It is a further object of the present invention to provide a
sheet material that is both absorbent and cut-resistant.
[0012] Yet another object of the present invention is to provide a
sheet material that can be used to slice food items while resisting
wear from the cutting tool and absorbing juices from the food
item.
[0013] A further object of the present invention is to provide a
sheet material that is resistant to shredding and can absorb
significant amounts of liquid produced by food items.
[0014] Another object of the present invention is to provide a
cut-resistant and absorbent sheet material that is readily
disposable.
[0015] Yet another object of the present invention is to provide a
cut-resistant and absorbent, sheet material that is easily
foldable.
[0016] Another object of the present invention is to provide a cut
resistant and absorbent sheet material that can be divided into
smaller sections.
[0017] A further object of the present invention is to provide a
cut-resistant and absorbent sheet material that does not have a
plastic-like appearance.
[0018] It is another object of the present invention to provide a
protective and absorbent sheet material that can provide an
indication of whether it has already been used.
[0019] To achieve the foregoing and other objectives, a
cut-resistant and absorbent sheet, is provided. The sheet comprises
an absorbent material and a cut-resistant material attached to the
absorbent material. The cut-resistant material has a plurality of
openings, and has an open area of less than about 50 percent.
[0020] According to another aspect of the invention, a sheet
material is provided which comprises an absorbent material and a
cut resistant material attached to the absorbent material. The
sheet material exhibits a slice resistance of at least about 30
kgf/cm. In addition, the sheet material will stain after contact
with liquid.
[0021] Still other objects of the present invention will become
apparent to those skilled in this art from the following
description wherein there is shown and described preferred
embodiments of this invention, including a best mode currently
contemplated for carrying out the invention, simply for the
purposes of illustration. As will be realized, the invention is
capable of other different aspects and embodiments without
departing from the scope of the invention. Accordingly, the
drawings and descriptions are illustrative in nature and not
restrictive in nature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] While the specification concludes with claims particularly
pointing out and distinctly claiming the invention, it is believed
that the same will be better understood from the following
description of preferred embodiments, taken in conjunction with the
accompanying drawings in which:
[0023] FIG. 1 is a segmented perspective view of an exemplary
absorbent and protective sheet of material, made according to
principles of the present invention;
[0024] FIG. 2 is a segmented perspective view of another exemplary
absorbent and protective sheet, made according to principles of the
present invention;
[0025] FIG. 3 is a segmented perspective view of yet another
embodiment of an absorbent and protective sheet, made in accordance
with principles of the present invention;
[0026] FIG. 4 is a segmented perspective view of another exemplary
absorbent and protective sheet, made according to principles of the
present invention;
[0027] FIG. 5 is a segmented perspective view of an additional
exemplary absorbent and protective sheet having tear lines and seal
lines formed therein, in accordance with principles of the present
invention;
[0028] FIG. 6 is a segmented perspective view of another embodiment
of an absorbent and protective sheet of material, made in
accordance with principles of the present invention; and
[0029] FIG. 7 is a segmented perspective view of yet another
exemplary absorbent and protective sheet, made according to
principles of the present invention;
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0030] Turning now to the drawings in detail, wherein like numerals
indicate corresponding structure throughout the views, FIG. 1 is a
partially-segmented perspective view of an exemplary absorbent and
protective sheet of material 20, made according to principles of
the present invention. In this embodiment, the material 20
comprises two layers, an upper cut-resistant layer 22 which covers
a lower absorbent layer 24 and is attached thereto. The two layers
22 and 24 can be attached in any suitable manner, such as by
bonding or laminating the cut-resistant layer 22 to the absorbent
layer 24, or by casting or extruding the cut-resistant layer 22 to
the absorbent layer 24. The lower surface 36 of the cut-resistant
layer 22 is adjacent the upper surface 34 of the absorbent layer
24. In this embodiment, the sheet 20 includes a cutting surface 30,
which is defined by the cut-resistant layer 22, and a base surface
32, which is defined by the absorbent layer 24. Preferably, the
surfaces 30 and 32 are substantially planar, and the thickness of
the sheet between these two surfaces is between about 0.010 inches
and about 0.060 inches. By making the cutting surface 30
substantially planar, food items may be easily cut on this surface
without interference from grooves or other structures.
[0031] The absorbent layer 24 can be formed from a suitable
absorbent material for absorbing and/or containing the fluids of
interest. Suitable materials include fibrous webs or sheets of
material formed from fibers of natural (e.g., cellulosic) and/or
synthetic origin, including hollow fibers and capillary channel
fibers. Other suitable materials which can be included in the
absorbent layer 24 include absorbent polymeric foams, absorbent
polymeric gelling materials, hydrogels, natural starches and gums.
Materials of particular interest include cellulosic substrates such
as paperboard. The absorbent layer 24 may comprise one integral
layer of material or may comprise a laminate structure having
multiple layers of the same or diverse composition. Moreover, the
absorbent layer 24 may comprise a carrier web that itself may or
may not be absorbent, but which may carry an absorbent material.
Preferably, the absorbent layer 24 has two surfaces 32 and 34 which
are substantially planar, the thickness between the two surfaces
preferably being between about 0.005 inches and about 0.050 inches,
preferably between about 0.010 inches and about 0.015 inches.
[0032] The cut-resistant layer 22 may be formed from any durable
material or materials which are substantially resistant to cutting,
abrasions, and shredding from cutting utensils used for food
preparation, such as kitchen knives for instance. Typical materials
which are known in the art as exhibiting such properties may be
utilized, including those which typically exhibit a high degree of
toughness and an interlocked molecular structure of comparatively
high molecular weight. In addition, the cut-resistant layer 22 is
preferably formed from a material or materials which can be bonded,
laminated, cast, extruded, coated, sprayed, adhered, or otherwise
applied to the absorbent layer 24. Suitable materials include a
polymeric layer bonded, adhered, or laminated to the absorbent
layer 24, thermoplastic or thermoset resins directly case or
extruded onto the absorbent layer. Exemplary materials to be used
for the cut-resistant layer 22 include polymeric materials, such as
ethylene vinyl acetate (EVA), high density polyethylene (HDPE),
styrene including polystyrene, low density polyethylene (LDPE),
linear low density polyethylene (LLDPE), polyvinyl chloride (PVC),
plastisols, crystallized polyethylene teraphthalate (CPET),
polyethylene teraphthalate (PET), polyethylene teraphthalate glycol
modified (PETG), polypropylene (PP), and polyurethanes, as well as
polymeric composite materials and copolymers. A selection of
material for the layer 22 can be made based upon the cut-resistance
and hydrophilicity desired. Those materials which are more
hydrophilic, such as CPET for example, are of particular interest
in forming the layer 22. Other substances and additives may be
provided within the cut-resistant layer 22 to enhance and/or add
various properties and/or to reduce the cost of the layer. For
example, anti-bacterial agents, deodorizing agents, coagulating
agents, and/or low-cost fillers could be utilized. Moreover,
although the cut-resistant layer 22 is shown in FIG. 1 as an
integral layer, it should be understood that the layer could
comprise a laminate structure having multiple layers of similar or
differing materials.
[0033] Preferably, the cut-resistant layer 22 comprises a flat
polymer sheet having substantially planar surfaces 30 and 36, the
preferred thickness of the polymer between the surfaces being
between about 0.005 inches and about 0.020 inches, and most
preferably about 0.010 inches. If desired, a design, pattern, or
texture can be embossed, pressed, or otherwise applied to the
surface 30 of the layer 22, to provide a desired finish and
appearance. For example, it may be desirable to apply a matte
surface to the layer 22, such as by embossing for example, to
provide a matte appearance or non-glossy surface.
[0034] As shown in the embodiment of FIG. 1, a plurality of
drainage openings 26 are formed in the cut-resistant layer 22. Any
suitable process for forming the openings 26 in the layer 22 may be
utilized. For example, the openings 26 may be drilled, punched,
pressed, perforated, or molded into the layer 22. Each opening 26
extends from the cutting surface 30 to the lower surface 36 of the
layer 22, and allows liquids that may be present at the cutting
surface 30 to travel through the cut-resistant layer 22 and be
absorbed by the absorbent layer 24. The location, shape, number,
and size of the openings 26 can be varied as desired to obtain
adequate drainage, absorbency, and cut-resistant. As an example,
round openings of about {fraction (1/16)} of an inch in diameter
can be utilized, at a density of about 36 openings per square inch.
Preferably, the openings 26 are spaced between about 0.1 inches to
about 0.5 inches apart, and most preferably about 0.1875 inches
apart. A density of between about 10 and about 200 openings per
square inch is preferred. It is also preferred that the openings 26
are approximately evenly spaced. Moreover, it is preferred that the
openings have a maximum dimension (e.g. diameter) of from about
0.010 inches to about 0.100 inches. The perforation pattern may be
varied if desired, with the density of openings being greater in
areas where absorbency is most desired (e.g., around the periphery
of the sheet), and lesser elsewhere.
[0035] Also, it is preferred that the total surface area of the
openings 26 on the surface 30 is less than the total surface area
of the solid region 38 between the openings 26 (e.g., the
cut-resistant layer 22 has an open area of less than about 50
percent). This configuration is preferred because, when the
openings 26 become so large as to take up significant amounts of
the surface area of the surface 30, the protection provided by the
layer 22 begins to diminish, and the chances increase that the
openings 26 will interfere with cutting operations.
[0036] Accordingly, the exemplary sheet material 20 of FIG. 1 can
be used as an effective protective material. The base surface 32
can be placed on a supporting surface, such as a counter top, and
food items can be placed on the cutting surface 30, where they may
be cut, sliced, or otherwise processed. Because the openings 26
provide fluid communication between the cutting surface 30 and the
absorbent layer 24, juices from the food items may drain through
the openings 26 and into the absorbent layer 24 where they are
absorbed and contained. Once the food items have been prepared, the
sheet 20 may be discarded.
[0037] As shown in FIGS. 2, 5, and 6, in addition to a
cut-resistant layer 22 and absorbent layer 24, other layers and
materials may be provided to form the sheet material 20. For
example, in the embodiment of FIG. 2, a cover layer 40 is provided
over the top surface 30 of the cut-resistant layer 22. Accordingly,
in the embodiment of FIG. 2, the top surface 42 of the cover layer
is provided as the cutting surface. The cover layer 40 can comprise
any material capable of being bonded, adhered, laminated, or
otherwise applied to the surface 30 of the cut-resistant layer 22.
For example, the cover layer 40 can be laminated or melt bonded to
the cut-resistant layer 22. Preferably, the cover layer 40 and/or
the absorbent layer 24 each comprise a material that can absorb and
be stained by liquid. Accordingly, the cover layer 40 and/or the
absorbent layer 24 can stain and indicate that cutting has occurred
on the sheet 20, providing an indication to the user not to re-use
the sheet, as it may be contaminated. It is also preferred that the
cover layer 40 and/or the absorbent layer 24 is of a color such
that stains provide such a use indication. The stains in the
absorbent layer 24 can be viewed through the apertures 26 in the
cut-resistant layer 22. Also, the cut-resistant layer 22 can be
somewhat translucent or transparent so that stains in the absorbent
layer 24 can be viewed from the exterior of the sheet 20.
[0038] Suitable materials to construct the cover layer 40 include
non-woven materials, fabrics, paper materials, and/or fibrous
materials. Preferably, the chosen material is laminated to the
cut-resistant layer 22 to minimize shredding of the cover layer.
(Shredding of the materials of the sheet 20 is not desirable, as it
may introduce foreign materials into the food item being processed
on the sheet). Fibers of natural (e.g., cellulosic) and/or
synthetic origin can be utilized for the cover layer 40. For
instance, a spunbonded fabric could be utilized, such as
REEMAY.RTM. 2250 or REEMAY.RTM. 2004, manufactured by Reemay, Inc.
In addition to providing a use indicator, the cover layer 40 can
provide a paper-like appearance to the sheet 20 and mask any
plastic-like appearance of the cut-resistant layer 22. Moreover,
the cover layer 40 provides slip-resistance, so it can prevent food
items from sliding off the sheet 20 when being cut on the surface
42 of the cover. In addition, the cover layer 40 can include
additive agents, such as surfactants, anti-bacterial agents,
etc.
[0039] Other features and properties can also be added to the
protective sheet. For example, in the embodiment of FIG. 3, the
cut-resistant layer 22 is made more flexible by forming fold lines
50 on one or more surfaces of the layer 22. In this figure, the
cut30 resistant layer 22 is shown partially pulled away from the
absorbent layer 24 in order to reveal the fold lines 50 which have
been formed on the lower surface 36 of the layer 22.
[0040] In this embodiment, the fold lines 50 comprise a plurality
of uni-directional grooves formed in the lower 36 surface. Any
suitable method for forming the lines 50 can be utilized, such as
by pressing, perforating, scoring, embossing, molding, etching,
folding, slicing, etc. In addition, the lines 50 could be provided
by removing material from the layer 22, or by providing flexible
material at the desired locations in the layer 22. Also, the fold
lines 50 can be provided in a variety of sizes, shapes, or
locations on the cut-resistant sheet 20, as desired. However, it is
preferred that the fold lines 50 are provided on the surface 36
which is opposite the cutting surface 30, to prevent the cutting
edge from falling into the lines during cutting, thereby creating
the risk that the food item will be mis-cut. It is also preferred
that the cutting surface 30 remains substantially planar, so as not
to interfere with cutting operations. The fold lines 50 could
comprise tear lines or score lines which weaken the material 22 so
as to make it less resistant to folding and/or tearing along the
lines.
[0041] The fold lines 50 provided allow the sheet 20 to more easily
flex and fold for additional ease in handling. In particular, the
fold lines 50 allow the sheet 20 to be more easily folded for
disposal within a trash container, and to keep the sheet
substantially folded after being placed in such a container.
Accordingly, by folding the sheet 20 along the fold lines 50, the
sheet 20 will be less cumbersome to discard and will take up less
space in the trash container.
[0042] Other configurations for the openings 26 and fold lines 50
can also be utilized. For example, in the embodiment of FIG. 4, the
openings 26 are formed as slits in cut-resistant layer 22 to
thereby provide fluid communication between the cutting surface 30
and the lower surface 36. Moreover, in this embodiment,
intersecting fold lines 50 and 50' are provided on the
cut-resistant layer 22, and these lines are provided on the surface
30.
[0043] Other configurations for the fold lines 50 can be utilized
which provide additional functions as shown in FIG. 5. In this
embodiment, the fold lines 50 are formed by removing entire
portions of the cut-resistant layer 22 so as to form holes or
perforations 27 therein. The line of holes 50 extends to the outer
edges of the layer 22 and thus can be used to tear the sheet into 2
or more smaller sheets. To prevent liquids which have penetrated
into the absorbent layer 24 from flowing out at the tear line 50,
the entire sheet 20 can be sealed on each side of the tear line 50,
such as by sealing along lines 60 and 60' of FIG. 5. Any
appropriate sealing mechanism can be used to form the seal lines 60
and 60', such as a hot bar sealer for example. Although FIG. 5
illustrates a tear line 50 to divide the sheet 20 into two smaller
sheets, additional lines 50 can be formed to separate the sheet
into three, four, or any desired number of smaller sheets.
[0044] As noted earlier, additional layers of material may be
utilized to form the sheet material 20, in addition to the
cut-resistant layer and the absorbent layer. For instance, in the
exemplary embodiment of FIG. 6, a backing layer 52 is provided on
the lower surface 32 of the absorbent layer 24. The backing layer
52 is preferably liquid impervious to restrain fluid from leaving
the absorbent layer 24 and contacting a support surface, such as a
countertop. The backing layer 52 may be formed from any material or
materials suitable for providing a layer, film, or coating for the
sheet 20. Suitable materials include polymeric films, thermoplastic
resins, or metallic foils. Materials such as vinyl acetate, EVA,
metallocenes, polyethylene, and polyurethane could be utilized, for
instance. The layer 52 can be bonded or laminated to the absorbent
layer 24, extruded or thermoformed onto the absorbent layer 24, or
printed, sprayed or otherwise applied to the absorbent layer.
Moreover, while it is preferred that the backing layer 52 comprise
one integral layer of material, a laminate structure having
multiple layers of the same or differing composition could be
utilized. For example, a polymer film, such as polypropylene for
instance, can be coated with a skid-resistant substance, such as a
high friction polymer for instance, to form the backing layer 52.
Also, the backing layer 52 can include additive agents, such as
surfactants, anti-bacterial agents, fillers, coatings, etc.
[0045] The backing layer 52 also preferably has a high coefficient
of friction so as to provide skid resistance to the sheet material
20. To provide skid resistance, the backing layer 52 preferably has
a coefficient of friction of at least about 0.3. While it is
preferred that the backing layer 52 be fluid impervious and/or
skid-resistant, the backing layer need not be cut-resistant.
Accordingly, the backing layer 52 can be thinner and more flexible
than the cut-resistant layer 22.
[0046] As shown in FIG. 6, additional absorbent capacity and
protection of underlying surfaces may be provided be providing a
raised lip or border 51 around the periphery of the cutting surface
30 of the sheet material. The lip 51 also facilitates grasping of
the sheet 20. Any suitable method of forming the lip 51 can be
utilized, such as embossing, crimping, or pressing for example.
Also shown in this embodiment is a fibrous material 40 which has
been laminated or otherwise bonded to the cutting surface 30 of the
cut-resistant layer 22. Such fibers can provide a matte or
non-glossy appearance to the cutting surface 30.
[0047] In the exemplary embodiment of FIG. 7, the sheet material
comprises four discrete layers. From top to bottom, the layers
include a cover layer 40, a cut-resistant layer 22, an absorbent
layer 24, and a backing layer 52. The layers may be bonded, sealed,
laminated, adhered, attached, or formed together by any suitable
methods, such as those described above for example. Suitable
materials for these four layers have also been described above with
respect to the other embodiments. As noted above, the cover layer
40 is preferably a non-woven, fibrous or paper-like absorbent
material to provide a non-plastic look to the sheet and to provide
an indicator of where cutting has occurred. The cut-resistant layer
22 preferably comprises a polymer or polymer composite and includes
drainage openings 26 to allow fluid communication between the cover
layer 40 and the absorbent layer 24. Moreover, the cut-resistant
layer 22 preferably includes transverse fold lines 50', and
longitudinal fold lines 50 on its lower surface 36 to provide
flexibility, and ease of folding and disposal. As noted above,
these lines are preferably formed on the surface opposite the
cutting surface 30, so as not to interfere with cutting operations.
The absorbent layer 24 is provided to draw in and contain fluids,
and the backing layer 52 is liquid impervious to prevent fluids
from escaping from the sheet 20. Preferably, the backing layer 52
is also skid-resistant.
EXAMPLE 1
[0048] A sheet material such as that of FIG. 7 is formed by the
following exemplary method. A piece of REEMAY 2250 nonwoven PET
fabric is placed on top of a flat sheet of CPET. These two pieces
are then placed on top of a piece of silicon rubber, the CPET sheet
being adjacent the rubber. The silicone rubber ensures even
distribution of pressure during pressing. Next, a steel plate with
a fine grit texture is placed on top of the nonwoven fabric. The
entire laminate is then pressed at 325 F for 20 seconds at 150 psi.
When the laminate is removed, the fabric and the CPET will have
fused leaving a unitary sheet. The side of the unitary sheet in
contact with the silicon rubber will be smooth. The side in contact
with the steel plate will have a fibrous texture and appearance and
a dull finish.
[0049] After the unitary sheet is formed, holes are created using a
punch and die mechanism. This method fully removes material from
the sheet while introducing very little stress to the sheet,
enabling the sheet to remain substantially flat after the
operation.
[0050] Next, fold lines are created. There are a variety of methods
to incorporate fold lines such as creasing, perforating, or
otherwise selectively weakening desired areas of the sheet. In one
exemplary method, a steel rule perforating die is used to form a
perforated line in the sheet.
[0051] Next, an absorbent sheet, such as a paper towel with a
polymer backing sheet, is secured to the punched sheet. The
absorbent paper towel is secured to the smooth side of the CPET
sheet. Thus, the resulting layered structure includes an apertured
top layer which comprises a CPET sheet fused with a nonwoven
fabric, an absorbent middle layer, and a polymer backing layer.
[0052] Food items may be cut on the fabric side of the layered
sheet structure, and the holes in the top layer allow fluid to
drain to the middle absorbent layer. The CPET sheet is resistant to
cutting and abrasions. Also, the absorbent and the non-woven fabric
can stain upon use, indicating that the sheet has been used and may
be contaminated. The stains in the absorbent can be viewed through
the apertures and through the substantially translucent CPET sheet.
The polymer backing layer helps to prevent fluid from escaping the
absorbent. When cutting is finished, the fold/tear lines formed in
the top layer allow the sheet to be easily folded and disposed.
[0053] Thus, sheet materials made in accordance with preferred
embodiments of the present invention have cut resistance,
absorbency, stain indication capability, and foldability.
[0054] As used herein, the term "absorbent efficiency" is used to
refer to a derived parameter which has been found useful to
characterize sheet materials and determine whether they perform
satisfactorily in the food preparation environment. The absorbent
efficiency takes both absorption rate and capacity into
account.
[0055] In a disposable food preparation mat, it is desirable to
have a mat that absorbs a sufficient quantity of fluid in a
reasonable period of time. It is also desirable for the mat to be
relatively thin (most preferably 0.076 cm) to maintain good
conformability to the work surface and to have an impression of
disposability. An absorbent efficiency can then be defined as:
Efficiency=(Capacity*Rate*10.sup.4)/thickness
[0056] where capacity has units of g.sub.water/cm.sup.2, rate has
units of g.sub.water/(s*cm.sup.2), thickness has units of cm, and
absorbent efficiency has units of (g.sub.water/cm.sup.2)
(g.sub.water/(s*cm.sup.2)) (1/cm). Hence, the absorbent efficiency
is maximized by maximizing the absorbent capacity and rate, and by
minimizing the mat thickness.
[0057] A typical practice in preparing food is slicing fruit. As
most fruits are sliced they exude aqueous juices. Especially juicy
fruits--oranges for example--may exude up to 10 g of juice per
fruit. It is desirable that the food preparation mat or sheet
entirely absorb all 10 g of this juice within 30 seconds to
facilitate clean disposal of the mat. A typical food preparation
mat has an area of approximately 650 cm.sup.2 and is most
preferably 0.076 cm thick. Thus, it is preferred that a food
preparation mat have an absorbent efficiency as defined above of at
least 0.2.
[0058] As utilized herein, the term "slice resistance" (or "cut
resistance") is used to refer to a derived parameter which has been
found useful to characterize sheet materials and determine whether
they perform satisfactorily in the food preparation
environment.
[0059] Based on extensive consumer testing, a food preparation mat
must have a slice resistance of at least 2.27 kgf (5 lbf), as
measured using the slice resistance test discussed below, so that
an average consumer will not cut through the protective surface
during a single use. In addition, the thickness of the kitchen food
preparation mat should be minimized to reduce waste, increase the
consumers' likelihood to dispose of the sheet, and make the sheet
easier to store. Therefore, the thickness of the food preparation
sheet should be less than 0.254 cm (0.100 in), more preferably less
than 0.127 cm (0.050 in), most preferably less than 0.076 cm (0.030
in). In order for a structure to provide a slice resistance of at
least 2.27 kgf (51 bf) at the maximum most preferably thickness of
0.076 cm(0.030 in), the structure must have a minimum unit slice
resistance of 30 kgf/cm (2.27 kgf/0.076 cm=30 kgf/cm).
[0060] In addition, the top surface of the sheet material and/or
the absorbent layer of the sheet material should have the
capability to stain when in contact with fluids. It is preferred
that the stains in the absorbent can be viewed through the
apertures in the cut-resistant layer and also that the layers on
top of the absorbent allow at least some light to pass through so
that stains in the absorbent can be viewed. A sheet that shows
stains after contact with fluid is desirable as it indicates to the
user that the sheet has been used.
[0061] Thus, sheet materials in accordance with this preferred
embodiment of the present invention exhibit absorbency, slice
resistance, the ability to stain, and foldability.
TEST METHODS
[0062] The following test methods have been developed and utilized
for characterizing sheet materials in accordance with the present
invention.
[0063] Absorbency Rate
[0064] 1) A 36 in.sup.2 (232.26 cm.sup.2) sample is weighed and
placed directly under a Buret.
[0065] 2) 10 cc of distilled water is dispensed from the Buret onto
the sample.
[0066] 3) The water is permitted to absorb for 30 seconds.
[0067] 4) At 30 seconds, the sample is tapped 10 times on its side,
removing any non-absorbed water.
[0068] 5) Weigh the sample and record the weight.
[0069] 6) Calculate the absorbency rate as (final weight-initial
weight)/time. The units are g.sub.water/s.
[0070] 7) Calculate the unit absorbency rate as ((final
weight-initial weight)/time)/sample area. The units are
g.sub.water/(s*cm.sup.2).
[0071] 8) Test 3-5 samples per above.
[0072] 9) Report average of sample values.
[0073] Absorbent Capacity
[0074] 1) A 16 in.sup.2 (103.22 cm.sup.2) sample is weighed and
placed into a container of distilled water, completely
submerged.
[0075] 2) The sample remains completely submerged for 120
seconds.
[0076] 3) At 120 seconds, the sample is removed from the water and
permitted to drip dry for 30 seconds.
[0077] 4) At the completion of the 30 second drip dry, the sample
is shaken 1 time to remove residual water.
[0078] 5) Weigh the sample and record the weight.
[0079] 6) Calculate the capacity as (final weight-initial
weight)/sample area. The units are g.sub.water/cm.sup.2.
[0080] 7) Test 3-5 samples per above.
[0081] 8) Report average of sample values.
[0082] Absorbent Efficiency
[0083] 1) Calculate the absorbent efficiency as
Efficiency=(Capacity*Rate*10.sup.4)/thickness
[0084] Slice Testing Apparatus
[0085] The test apparatus described applies a known force in the z
(vertical) direction on a knife blade to measure the cut resistance
of a sample. A knife blade is placed in the knife holder. The knife
blades used for all testing were Poultry Blades Code #88-0337 by
Personna. The test sample is mounted to a sample platform. The
knife blade is then brought into contact with the sample. A known
load is applied to the knife blade in the vertical direction. The
sample platform is then moved at a rate of 8 inches per second for
4 inches under the weight of the knife blade creating a slice.
Consecutive slices of increasing load are made until the knife
blade cuts through the sample. The knife force required to
penetrate completely through the sample is recorded. Slice
resistance is calculated as the slice force/sample thickness.
Replicate test on 3-5 separate samples and report average
values.
[0086] Visible Staining
[0087] 1) A solution of 200 grams of water to 0.1 gram of red food
coloring is prepared. The food coloring is KROGER FOOD COLORS.RTM.
#11110 66987, and contains water, propylene glycol, and Red 40.
[0088] 2) Using a syringe, one gram of the solution is deposited
over approximately four square inches of the sample
[0089] 3) The solution is allowed to "wet out" into the absorbent
layer and inspected for color and/or stain.
[0090] 4) After one minute, the surface is wiped off using a damp
paper towel and again inspected for color and/or stain.
[0091] 5) Steps 1-4 are repeated using blue food coloring in the
solution rather than red. The food coloring is KROGER FOOD
COLORS.RTM. #11110 66987, and contains water, propylene glycol, and
Blue 1.
[0092] 6) Steps 1-4 are repeated replacing the solution with
WELCH'S.RTM. 100% Grape Juice (#41800 20750) made from water and
grape juice concentrate.
VISIBLE STAINING EXAMPLE
[0093] The above visible staining test was performed on a sheet
material made in accordance with Example 1 described above and on a
CHOP N CHOP.RTM. non-disposable cutting board #47643 50150. The
CHOP N CHOP.RTM. cutting board was made of polypropylene with a
slightly textured surface, approximately 0.022" in thickness and
manufactured by New Age Products, U.S. Pat. No. 5,472,790.
[0094] Even with the relatively low concentration of food coloring
(0.005%), visible staining was evident in the sheet material made
according to Example 1 above, both after the solution was allowed
to wet out, and after the surface was wiped off. The results were
similar when the grape juice was used on the sheet material, except
that the staining on the sheet material was even darker.
[0095] However, when the solution was applied to the CHOP N
CHOP.RTM. cutting board, there was little or no evidence of
discoloration to the cutting board and no absorbance of the liquid.
Also, when the CHOP N CHOP.RTM. cutting board was wiped with a damp
paper towel, there was no evidence of staining of the cutting
board. The results were similar when grape juice was applied, and
no staining was visible on the cutting board after the grape juice
was wiped off.
[0096] The foregoing descriptions of the preferred embodiments of
the invention have been presented for purposes of illustration and
description only. They are not intended to be exhaustive or to
limit the invention to the precise forms disclosed, and
modifications and variations are possible and contemplated in light
of the above teachings. While a number of preferred and alternate
embodiments, systems, configurations, methods, and potential
applications have been described, it should be understood that many
variations and alternatives could be utilized without departing
from the scope of the invention.
[0097] Thus, it should be understood that the embodiments and
examples have been chosen and described in order to best illustrate
the principals of the invention and its practical applications to
thereby enable one of ordinary skill in the art to best utilize the
invention in various embodiments and with various modifications as
are suited for particular uses contemplated. Accordingly, it is
intended that such modifications fall within the scope of the
invention as defined by the claims appended hereto.
* * * * *