MXPA97009767A - Improved recreated paper absorbent paper and method for factory - Google Patents

Abstract

The present invention relates to a method for making an absorbent paper fabric of the creped and bonded type having improved volume resistance to peel strength characteristics, comprising the steps of: (a) printing a low density pattern of a stock material; joining on a first side and a second side of a paper fabric with a gravure roll having a pattern defined thereon at a depth which is from about 30 to about 100 microns, (b) in a sequence not particular with respect to step (a), printing a high density pattern of a bonding material on the first side of the paper tissue, steps (a) and (b) being carried out so that the pattern of high The density of the bonding pattern penetrates the tissue of paper by a distance that is from about 166 to about 470% of the distance at which the low density pattern of the bonding material penetrates the tissue, said high density pattern being visible only on the first side of the fabric, and (c) creping the paper tissue to a degree that is sufficient to impart a significant degree of volume to the areas of the paper tissue having the low density pattern of the bonding material printed on it. the same, but not to the areas of the tissue of paper that have the pattern of high density printed on them, so that both characteristics of superior volume and resistance to the superior peeling are imparted to the tissue product absorb

Description

IMPROVED RECREATED PAPER ABSORBENT PAPER AND METHOD TO MANUFACTURE FIELD OF THE INVENTION This invention relates to an improved weave absorbent fibrous fabric material that is made from papermaking fibers for use as disposable sanitary towels and cleaners and to a method for manufacturing such material.

DESCRIPTION OF PREVIOUS ART Companies such as Scott Paper Company, the assignee of the present, continue to develop disposable absorbent paper substitutes for conventional cloth products such as wipes, tissues and towels.

To successfully win consumer acceptance, such products must closely simulate a cloth or cloth in both consumer perception and operation. Therefore, certain physical properties must be present in a successful product, including softness, strength, stretchability, absorbency, ability to dry clean, volume and abrasion resistance. Depending on the intended use of the product, some properties are more desirable than others. Softness is highly desirable for almost all absorbent paper products regardless of the intended use. This is true not only because consumers find that it is more pleasant to handle soft products but also that softness allows the product to easily conform to the shape dictated by work requirements. Resistance and ability to stretch are two other desirable properties, particularly in products that will be used for heavy duty applications. It is also desirable for a product to have a good resistance to abrasion if it is to be used for cleaning, scrubbing, et cetera. For products that are designed to be used as a facial tissue, poor abrasion resistance can result in a dust or fraying of the fibers of the product when handled by the consumer. The volume is important not only because it allows the paper product to have a cloth or cloth type feel, but also because it is favorably interrelated to other desirable properties, such as softness and absorbency.

Some properties tend to be inversely related, meaning that an increase in a property is usually accompanied by a decrease in another property. For example, an increase in the density of the fabric or the concentration of fiber (the proximity of the fibers to each other, increases the capacity of the fabric for dry cleaning or collecting moisture, due to the mostly capillary action of The small spaces between the fibers, however, an increase in the proximity of the fibers decreases the space between the fibers that is available to retain moisture, and therefore reduces the absorbency, in terms of quantity, of the fabric. Even more demonstrative example of the adverse interrelationship between properties is represented by the relationship between strength and softness.It has been generally believed that the conventional methods used to produce soft paper necessarily result in a reduction in strength. that conventional paper products are formed from aqueous solutions, and that their main source of resistance are the interfiber bonds that are formed by The process of hydrate binding associated with papermaking. Paper that has a heavy concentration of such papermaking joints is usually rigid. To soften the paper, it is necessary to reduce the rigid joints, an action that also results in a loss of strength. The most commonly used method to reduce the joints for making rigid paper is to cre- ate the paper from the drying surface with a doctor blade, interrupting and breaking many of the interfiber bonds in the paper web. Other methods that have been used to reduce the joints contrast with creping by avoiding the formation of joints, rather than breaking them after they are formed. Examples of these other methods are the chemical treatment of fibers to make paper to reduce their interfiber bonding capacity before they are deposited on the wet forming surface, the use of unrefined fibers in the solution, the inclusion within of the synthetic fiber solution not exhibiting the ability to form paper-making bonds, and the use of very little or no compression of the fabric to remove water from the paper cloth after it has been deposited on the forming surface of the paper. cloth. The latter method reduces the formation of the joints by reducing the close contact of the fibers with one another during the forming process. All these methods can be used successfully to increase the softness of paper fabrics, but only with the accompanying loss of resistance in the fabric.

Attempts to restore lost strength by reducing paper-making joints include adding bonding materials to the fabric that are capable of adding strength to a greater degree than adding rigidity to the fabric. One method that has been used to apply binding materials to the fabric is to add the binding material to the aqueous solution of fibers and deposit it on the fabric forming surface together with the fibers. With this method, the bonding material can be distributed evenly through the fabric, avoiding the roughness that could accompany concentrations of bonding material. However, this method reduces the absorbency of the fabric because it fills the pores between the fibers with bonding material. This also joins the fabric evenly, whose disadvantages will be explained subsequently.

Another method that has been used to apply the binding material to the fabric is to apply the bonding material in a spaced-apart pattern to the fabric. With this method, most of the cloth surface does not contain a binding material of absorbency reduction. Fabrics made entirely or mainly from paper fibers require binding areas that are very close together because the fibers for making paper are very short, generally less than a quarter of an inch in length. Initially it was thought that to apply sufficient bonding material in a pattern to a paper web to a degree necessary to join each fiber in the net would result in a rough sheet having poor softness characteristics, particularly in the areas where the bonding material it's located. However, U.S. Patent No. 1,294,794 discloses a method that mitigates such roughness which, in its preferred form, consists of first forming a fibrous web under conditions that result in a very low interfiber bond strength. The strength is then imparted to the fabric by applying bonding material to a surface of the fabric in a thin spaced-apart pattern. The roughness in the bonded areas is reduced by tightly adhering the joined parts of the fabric to a creping surface and removing with a doctor blade, thereby finely creping the joined parts to soften them. This controlled creping form also results in a number of other property improvements. For example, selective creping of the bonded areas on the surface of the fabric creates shrinkage of the fabric surface in all directions, resulting in an increase in strength in both the machine direction and the transverse direction of the fabric. . Also, the parts of the fabric where the bonding material is not localized are generally interrupted by the creping action resulting in an increase in the fabric volume, an increase in the softness of the fabric and an increase in absorbency. In certain places within the fabric, near the bonding material, the fabric develops internal split parts which also improve the absorbency, softness and volume of the fabric. It is this effect on the proportions where the bonding material is not localized that does not exist in at least some extent in the fabric formed by the addition of the binding material to the aqueous fiber solution. This method produces a paper fabric with a surprising softness and resistance, two properties which previously were believed to be almost mutually exclusive. A fabric with excellent absorbency properties is also produced because the bonding material being confined to a minor part only of the fabric surface. In addition, the compaction of the surface fibers due to the shrinkage of the bonded parts on the fabric creates a surface of the fabric which has improved cleaning-drying characteristics. It is also believed that the compression of the fabric to a creping surface while the fabric has wet portions in the surface region due to the non-dried or uncured bonding material causes the fibers in those areas to be compacted. This method is particularly useful in the production of fabrics of lower base weight range for such uses as bathroom tisus.

Unfortunately, the method described in British Patent '794 has disadvantages for making fabrics for heavier work use such as for facial tissues and towels where greater strength, volume and absorbency is desired. Examples of such disadvantages are poor abrasion resistance (or excessive fraying and dusting) and lack of ability to retain fiber on the unbonded side of the fabric in the fabric, as well as lesser strength in the overall fabric. of what can be desired. These properties can be improved by causing the bonding material to fully penetrate through the fabric to create a network of bonding materials that passes completely through the fabric, but the fabric will benefit less from the improvements provided by the invention. of the British patent '794. The bonding of the fabric with the bonding material fully extended through the fabric will greatly reduce the disruption of the fibers within the fabric with the creping, and therefore, will result in a reduction in volume, softness and absorbency. Also, full penetration of the material bond through the fabric is difficult to achieve on heavier weight basis fabrics and attempts to do so result in concentrations of excess bond material on the cloth surface where much of this is ineffective for reinforcing the interfiber joints. Furthermore, if full penetration of the bonding material results, the bonding material inside the fabric will not be efficiently used to increase the abrasion resistance of the fabric as when it is placed only on the surface of the fabric. The placement of the bonding material inside the fabric is not only an inefficient use of the expensive bonding material, but results in a rougher touch of the fabric due to the lack of skill of the creping action to soften the parts united so effectively. Also, a desirable feature of the invention '794 that would be reduced by fully bonding through the fabric is the ability to create a surface of compacted fiber cloth having good wiper-drying characteristics while at the same time creating a fabric voluminous able to absorb a large amount of moisture. These properties are only minor when a product is produced for such uses as bathroom tissue, but where the product is to be used for cleansers, facial tissues or towels is very important. This disadvantage harms the invention '794 as a method for producing a cleanser, a facial tissue or a towel product.

An improvement over the invention of the British patent '794 is described in the United States patent No. 4,326,000 issued to Roberts and involves a first surface region of laminate type having a surface bonding material placed therein , preferably in a spaced-apart and fine pattern, for bonding the fibers in a strong web within the surface region and for imparting an abrasion resistance to the side of the fabric. The penetrating bonding material is placed within the central core region in a thin spaced-apart pattern that occupies less area in the plane of the fabric than the surface bonding material in the first surface region. This penetrating bond material in the central core region extends completely through the central core region and connects the two surface regions together. In order to interconnect the two surface regions, the penetrating bonding material extends through the central core region into at least one fiber thickness of the fabric surface opposite to the first laminate type surface region, but it also increases the resistance to abrasion to the second opposite surface. The second surface region has no pattern of surface bonding material apart from the penetrating bonding material and is merely the outer surface of the central core region in which case the fabric has only two planar regions. In terms of appearance, the pattern of the penetrating bonding material is visible on both sides of the creped product.

Even though the Roberts process represents a significant improvement in terms of product property optimization, there is an inverse relationship between volume generation and peel pressure resistance (z-direction) meaning that as the product increases in volume, the Resistance to peeling is decreased, sometimes to the point where the total delamination of the leaf occurs. There is a need in this technology area for a process that allows high volume generation without sacrificing peel strength. In addition, the industry is constantly looking for products that have improved aesthetic characteristics, so improvements in this area are very welcome.

SYNTHESIS OF THE INVENTION Therefore, it is an object of the invention to provide a process of the general type described above which allows a high volume generation without sacrificing the peel strength. It is also a further object of the invention to provide a product having superior aesthetic characteristics.

In order to achieve the above-mentioned and other objects of the invention, a method for making a creped and bonded absorbent paper web having improved peel resistance volume characteristics includes the steps of (a) printing a low pattern. density of the bonding material on a first and a second side of a paper web; (b) in a non-particular sequence with respect to step (a), printing a high density pattern of a bonding material on the first side of the paper web, steps (a) and (b) being carried out so that the high density pattern of the bonding material penetrates into the paper web by a distance that is from about 166 to about 470 percent of the distance by which the low density pattern of the bonding material penetrates within of the cloth; and (c) creping the paper web to a degree that is sufficient to impart a significant degree of bulk to the areas of paper web having the low density pattern of bonding material printed thereon, but not the areas of the paper web having a high density pattern printed thereon, in this way both superior volume and superior peel strength characteristics are imparted to the absorbent fabric product.

A method for making a creped and bonded absorbent paper web having improved volume resistance to peel strength characteristics includes, according to a second aspect of the invention, the steps of (a) printing a low density pattern of a bonding material on a first and a second side of a paper web with a first gravure roll having a depth of about 30 microns to about 100 microns; (b) in a non-particular sequence with respect to step (a), printing a high-density pattern of a bonding material on the first side of the paper web with a second gravure roll having a depth of about 55 microns to around 125 microns; and (c) creping the paper web to a degree that is sufficient to impart a significant degree of volume to areas of the paper web having the low density pattern of bonding material printed thereon, but not to the areas of paper cloth having the high density pattern printed thereon, whereby both peel strength and superior volume characteristics are imparted to the absorbent cloth product.

An improved single layer absorbent fabric product includes, according to a third aspect of the invention, a bulky absorbent fabric predominantly comprising fibers for making paper, the bulky fabric having a first surface and a second opposing surface, and a pattern, the pattern includes at least one depression that is defined on the first surface but not on the second surface, whereby a single layer absorbent fabric product is provided having a defined pattern on one side of the fabric, but not on the other side.

These and several other advantages and features of the novelty characterizing the invention are pointed out with particularity in the appended claims that form a part thereof. However, for a better understanding of the invention, its advantages and the objects obtained by its use, reference is made to the drawings which form a part of the same, and to the accompanying descriptive matter, in which it is illustrated and a preferred embodiment of the invention is described.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic sample of an improved system for making an absorbent paper fabric of the bonded and creped type which is constructed according to a preferred embodiment of the invention; Fig. 2 is a fragmentary surface view of a first gravure roller in the system shown in Fig. 1; Figure 3 is a fragmentary surface view of a second gravure roller in the system shown in Figures 1 and 2; Figure 4 is a fragmentary cross-sectional view taken along lines 4-4 of Figure 2; Y Figure 5 is a drawing showing the surface texture of the first and second sides of a finished fabric product according to the description DETAILED DESCRIPTION OF THE PREFERRED MODALITIES Referring now to the drawings, wherein the like reference numbers designate a corresponding structure through the views, and referring in particular to FIG. 1, an improved system 10 for making an absorbent paper fabric of the bonded and creped type preferably includes , as is common in such systems, a twin wire former 12, a press section 14, a Yankee dryer 16, a perspiration dryer 18 and a creping section including a first printer 20, a first creping dryer 22, a second printer 24 and a second creping dryer 26. The system 10 further includes a setting dryer 28, a pair of cooling rollers 30 and a spool 32 for winding the finished absorbent paper product into a roll.

Apart from the novel aspects of the invention which are discussed below, the elements of system 10 mentioned above operate together in a conventional manner, which is well known to those skilled in this area of technology.

Referring now to Figures 2 and 4, it will be seen that the first printer 20 includes a first gravure roll 34 having an antecedent pattern of relatively low density 38 there defining a regularly separate pattern of canoe-shaped depressions 36. the bottom pattern 38 is a densified pattern 40 of canoe-shaped depressions 42 having a significantly greater depth and a greater volumetric capacity than the canoe-shaped depressions 36 of the bottom pattern 38. Referring to Figure 4, it will be seen that the depressions 36 of the bottom pattern have a depth Dx and that the depressions 42 of the densified pattern 40 have a depth D2. The D2 is preferably from about 140 to about 200% of the depth D2. This corresponds to a degree of penetration of the bonding material into the W fabric which is applied by gravure roll 34 for the densified pattern 40 which is from about 166 to about 470 percent of the degree of penetration that takes place for the pattern 38. Preferably, the depressions 36 of the bottom pattern will cause the bonding material to penetrate about 15 to 30% inside the thickness of the fabric, while depressions 42 will cause penetration of about 50 to 70% inside of the cloth.

Figure 3 is a fragmentary top surface view of a second gravure roller 44, which is part of the second printer station 24 shown in Figure 1. The second gravure roller 44 has only the background pattern 38 defined therein. , which is preferably identical to the bottom pattern 38 shown in Figures 2 and 4.

Preferably, the low density background pattern 38 is printed on from about 30% to about 50% of the total surface of both the first side of the fabric, by the first gravure roller 34, and of the second side of the fabric, by means of the second gravure roll 44. More preferably, the bottom pattern 38 is printed on about 40% of the total surface of both the first and second sides of the fabric.

The high density pattern 40 is preferably printed on from between about 5% to about 15% of the total surface of the first side of the fabric by the first gravure roller 34. More preferably, the high density pattern 40 is printed on about 8% of the total surface of the first side of the fabric.

Preferably, the depth Da of the bottom pattern 38 is from between about 30 to about 100 microns, with the most preferred depth of about 60 microns. The depth D2 is preferably between 55 microns to about 125 microns, with a more preferred depth of about 90 microns.

In operation, an absorbent fabric is formed by the twin wire former 12 and is dried by the press section 14, the Yankee dryer 16 and the perspiration dryer 18 in a manner that is well known in this area of technology. The fabric is then passed through the first printing station 20 where a bonding material, preferably a latex, is printed on a first side of the fabric by a first gravure roll 34. The pattern that is printed on the first Fabric side of the first gravure roll 34 will include the background pattern 30 discussed above, the densified pattern 40 which is also discussed in detail above. The printed fabric is then passed through the creping dryer 22 and creped to break the interfiber joints and increase the volume as is well known in the industry. The fabric is then passed to the second printer 24, wherein a second opposite side of the fabric W is printed by the second gravure roll 44 with the bottom pattern 38. The fabric is then passed through the second crepe dryer 26. , adding additional volume to the fabric. The fabric is then passed through the setting dryer 28, through a pair of cooling rollers 30 and onto the reels 32 for winding.

According to a novel aspect of the invention, and as shown in Figure 5, it has been found that by printing the bonding material in the densified and background patterns as specified above, that a visible pattern corresponding to the The densified pattern 40 printed on the first gravure roll 34 will appear as depressions on the first side of the cloth after the cloth leaves the second crepe dryer 26, and there will be no visible pattern on the second side of the cloth. Therefore, the process described herein results in a single layer absorbent fabric having a defined pattern on one side of the fabric, but not on the other side. In addition to the obvious ascetic advantages of the product, functional benefits, such as nesting resistance during winding, are also achieved.

It should be understood, however, that while numerous features and advantages of the present invention have been established in the foregoing description which together with the details of the structure and function of the invention, the description is only illustrative, and the changes may be made in details, especially in matters of form, sizes and arrangement of the parts within the principles of the invention for the full extent indicated by the broad general meaning of the terms in which the attached clauses are expressed.

Claims (30)

R E I V I N D I C A C I O N S

1. A method for making an absorbent paper fabric of creped and bonded type having improved volume characteristics to peel resistance, comprising the steps of: (a) printing a low density pattern of a bonding material on a first side and a second side of a paper web; (b) without a particular sequence with respect to step (a), printing a high density pattern of a bonding material on the first side of the paper web, steps (a) and (b) being carried out from so that the high density pattern of the bonding material penetrates into the paper web by a distance that is from about 166 to about 470 percent of the distance by which the low density pattern of the bonding material penetrates within the fabric, said high density pattern being visible only on the first side of the fabric; Y (c) creping the paper web to a degree that is sufficient to impart a significant degree of volume to the areas of the paper web having the low density pattern of the bonding material printed thereon, but not to the areas of the paper web having a high density pattern printed thereon, whereby both superior volume and superior peel strength characteristics are imparted to the absorbent fabric product. -5

2. A method, as claimed in clause 1, characterized in that said step (a) is carried out so that the low density pattern is printed on from about 30% to about 50% of the total surface 10 of both the first and the second sides of the fabric.

3. A method, as claimed in clause 2, characterized in that step (a) is carried out so that the low density pattern is printed on about 15 of 40% of the total surface of both the first and the second side of the fabric.

4. A method, as claimed in clause 1, characterized in that step (b) is carried out from Thus, the high density pattern is printed on from between about 5% to about 15% of the total surface of the first side of the fabric.

5. A method, as claimed in clause 4, characterized in that step (b) is carried out so that the high density pattern is printed on about 8% of the total surface of the side of the fabric.

6. A method, as claimed in clause 1, characterized in that step (a) is carried out with a gravure roll having a pattern defined thereon at a depth that is from between about 30 to about of 100 microns.

7. A method, as claimed in clause 6, characterized in that step (a) is carried out with a gravure roll having a pattern defined thereon at a depth which is about 60 microns.

8. A method, as claimed in clause 1, characterized in that step (b) is carried out with a gravure roll having a pattern defined thereon at a depth which is between about 55 microns to about of 125 microns.

9. A method, as claimed in clause 8, characterized in that step (b) is carried out with a gravure roll having a pattern defined thereon at a depth which is about 90 microns.

10. A method, as claimed in clause 1, characterized in that step (c) comprises creping the fabric twice for an additional volume.

11. A method for making an absorbent paper fabric of creped and bonded type having improved volume characteristics to peel resistance, comprising the steps of: (a) print a low density ur pattern. bonding material on a first and a second side of a paper web with a first gravure roll having a pattern defined thereon at a depth of about 30 microns to about 100 microns; (b) without a particular sequence with respect to step (a), printing a high density pattern of a bonding material on the first side of the paper web with a second gravure roll having a pattern defined thereon at depth that is around 55 microns to around 125 microns where the high density pattern is visible only on the first side of the cloth; Y (c) creping the paper web to a degree that is sufficient to impart a significant degree of volume to areas of the paper web having the low density pattern of bonding material printed thereon, but not to the areas of the paper cloth having the high density pattern printed thereon, whereby both peel strength and superior volume characteristics are imparted to the absorbent cloth product.

12. A method, as claimed in clause 11, characterized in that step (a) is carried out so that the low density pattern is printed on from between about 30% to about 50% of the surface total of both the first and the second sides of the fabric.

13. A method, as claimed in clause 12, characterized in that step (a) is carried out so that the low density pattern is printed on about 40% of the total surface of both the first and the second side of the cloth.

14. A method, as claimed in clause 11, characterized in that step (b) is carried out so that the high density pattern is printed on from between about 5% to about 15% of the surface total of the first side of the fabric.

15. A method, as claimed in clause 14, characterized in that step (b) is carried out so that the high density pattern is printed on about 8% of the total surface of the side of the fabric.

16. A method, as claimed in clause 11, characterized in that step (c) comprises creping the fabric twice for an additional volume.

17. A product made according to the method, as claimed in clause 1.

18. A product made according to the method, as claimed in clause 11.

19. An improved single stratum absorbent wet product comprising: a bulky absorbent fabric comprising fibers for making paper predominantly, said bulky fabric having a first surface and a second opposing surface; Y a pattern, said pattern comprises at least one depression that is defined in said first surface, but not in said second surface, whereby a single layer absorbent fabric product having a defined pattern on one side of the fabric is provided. , but not on the other side.

20. A product, as claimed in clause 19, characterized in that said second surface is relatively smooth, not having a defined pattern thereon.

21. A method for making an absorbent paper fabric of the bonded and creped type having improved volume resistance to peel strength characteristics, comprising the steps of: (2) printing a low density pattern of the bonding material on a first side and a second side of a paper web; (b) without a particular sequence with respect to step (a), printing a high density curvilinear pattern of a bonding material on the first side of the paper web, steps (a) and (b) being carried This is done so that the high density pattern of the bonding material penetrates into the paper web at a distance that is from about 166 to about 470 percent of the distance by which the low density pattern of the bonding material penetrates. inside the fabric; Y (c) creping the paper web to a degree that is sufficient to impart a significant degree of volume to the areas of the paper web having the low density pattern of the bonding material printed thereon, but not to the areas of the paper web having a high density pattern printed thereon, whereby both superior volume and superior peel strength characteristics are imparted to the absorbent fabric product.

22. A method, as claimed in clause 21, characterized in that step (a) is carried out such that the low density pattern is printed on from about 30% to about 50% of the total surface from both the first and the second sides of the fabric.

23. A method, as claimed in clause 22, characterized in that step (a) is carried out so that the low density pattern is printed on about 40% of the total surface area of both the first and the second side of the cloth.

24. A method, as claimed in clause 21, characterized in that step (b) is carried out so that the high density pattern is printed on from between about 5% to about 15% of the surface total of the first side of the fabric.

25. A method, as claimed in clause 24, characterized in that step (a) is carried out so that the high density pattern is printed on about 8% of the total surface of the side of the fabric.

26. A method, as claimed in clause 21, characterized in that step (a) is carried out with a gravure roll having a pattern defined thereon at a depth that is from between about 30 to about of 100 microns.

27. A method, as claimed in clause 26, characterized in that step (a) is carried out with a gravure roll having a pattern defined thereon at a depth which is about 60 microns.

28. A method, as claimed in clause 21, characterized in that step (b) is carried out with a gravure roll having a pattern defined thereon at a depth that is between about 55 microns to about of 125 microns.

29. A method, as claimed in clause 28, characterized in that step (b) is carried out with a gravure roll having a pattern defined thereon at a depth which is about 90 microns.

30. A method, as claimed in clause 21, characterized in that step (c) comprises creping the fabric twice for an additional volume. SUMMARY A method for making a creped and bonded absorbent paper web having improved volume to peel strength characteristics includes the steps of: (a) printing a low density pattern of a bonding material over a first and a second side of a paper cloth; and (b) without a particular sequence with respect to step (a), printing a high density pattern of a bonding material on the first side of the paper web. Steps (a) and (b) are carried out so that the high density pattern of the bonding material penetrates into the paper web by a distance that is from about 166 to about 470 percent of the distance by which the low density pattern of the bonding material penetrates into the fabric. This results in a fabric that has superior volume and peel strength characteristics. Another characteristic of the product is that it has a pattern of visible depressions on one surface, but not on the other surface, which creates an attractive aesthetic effect and has functional benefits as well.