CZ164499A3 - Paper web having relatively thinner continuous netting area and discrete relatively thicker areas in the continuous netting area - Google Patents

Abstract

A paper web and method of making the paper web are disclosed. In one embodiment the paper web includes a continuous relatively thinner region and a plurality of discrete relatively thicker regions. The relatively thicker regions are disposed in the plane of the relatively thinner region. The paper web can have a relatively patterned face and a relatively smooth face. The paper structures can be dried relatively quickly and efficiently, and can provide enhanced absorbency and bulk density while having a relatively smooth face.

Description

A paper web having a relatively thinner continuous network region and a discrete relatively thicker region in the plane of the continuous network region.

Technical field

The present invention relates to paper material, and in particular to a tissue paper web having both bulkiness and smoothness, and methods of making such tissue paper web.

BACKGROUND OF THE INVENTION

Paper materials such as toilet paper, paper towels and napkins are widely used both in the home and industry. Many attempts have been made to make consumers more preferable to these products.

One approach to obtaining consumer-preferred tissue paper products having both bulkiness and flexibility is illustrated in U.S. Patent 3,994,771, issued November 30, 197 to Morgan et al. This patent is hereby incorporated by reference into this description. Higher bulkiness and flexibility can also be achieved by side-by-side depressed and uncompressed zones, as shown in U.S. Patent 4,191,609, issued March 4, 1980 to Trokhan. This patent is also incorporated herein by reference.

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Another approach to making paper products more preferred by the consumer is to dry the paper material to give it greater bulkiness, tensile strength and less tear. Examples of paper materials made in this manner are illustrated in U.S. Patent 4,637,859, issued January 20, 1987 to Trokhan, which patent is hereby incorporated by reference. U.S. Pat. No. 4,637,859 discloses separate, domed-shaped elevations that are dispersed in a continuous network, and this patent is hereby incorporated by reference into this description. A continuous network can provide strength while relatively thicker domes can provide softness and absorbency.

One of the disadvantages of the papermaking method described in U.S. Pat. No. 4,637,859 is that drying such a web can be relatively energy intensive and expensive, and generally involves the use of a cross-air dryer. In addition, the papermaking method described in US 4,637,859 can be limited in terms of the speed at which the web can finally be dried on a Yankee drying drum. This limitation appears to be at least in part due to the pattern formed on the belt prior to its transfer to the Yankee drying drum. In particular, the separate domes described in US 4,637,859 need not be dried on the surface of a Yankee drying drum as effectively as the continuous web described in US 4,637,859. Therefore, at a given level of consistency and basis weight, the speed at which the drying drum can be Yankee operate.

The following publications show other methods of making a paper web and are hereby incorporated by reference into this description. WO 95/17548 published June 29, 1995 in the name of Ampulski et al. and having a US priority date of December 20, 1993, WO 96/00812, published January 11, 1996 in the name of Trokhan et al. with US date of priority June 29, 1994, WO 96/00814 ·······

3 published on January 11, 1996 in the name of Phan and having a priority date of June 29, 1994, U.S. Patent 5,556,509, issued September 17, 1996 to Trokhan et al. and U.S. Patent 5,549,790 issued to Phan

August 27, 1996.

U.S. Pat. Nos. 4,326,000, 4,000,237 and 3,903,342 disclose sheet materials having elastomeric binder materials joining sheet surfaces together in a pattern. Such a method has the disadvantage that the use of binder materials can be relatively expensive and difficult to control at production rates. In addition, the elastomeric binder material may reduce the absorbency of the web.

Conventional tissue paper produced by compressing the web with one or more compression felt in the compression nip can be produced at relatively high speeds. After drying, a pattern can be embossed into a web of conventionally compressed paper and the macro web thickness can be increased. For example, embossed patterns formed in tissue paper products after they have been dried are common.

However, extrusion processes generally give the paper material an aesthetic appearance at the expense of other material properties. In particular, extrusion into the dried paper web disrupts the bonding between the pulp fibers in the material. This deterioration occurs because the fiber embryonic fiber slurry is dried and fixed during drying. The displacement of the fibers perpendicular to the plane of the paper structure after drying of the paper material disrupts the bonds between the fibers. The breakage of the dried paper web results in a reduced tensile strength and, moreover, extrusion is generally performed after the dried paper web is creped with the drying drum, the creping may disrupt the creping pattern,

Extrusion to the supplied belt.

For example, extrusion may cancel fcfc at some points in the belt

creping pattern by compacting or stretching the creping pattern. Such a result is undesirable because the creping pattern improves the softness and flexibility of the dried web.

Paper scientists and engineers continue to seek improved methods for producing soft, strong and absorbent tissue paper that can be effectively dried at reduced cost.

Therefore, one object of the present invention is to provide a paper web and a multi-area paper web method that allows relatively fast drying with relatively low energy consumption and low cost.

It is a further object of the present invention to provide a multi-area papermaking method that can be produced on an existing paper machine (having conventional or cross air drying) without the need for substantial modification of the paper machine.

It is another object of the present invention to provide a paper web and a method of making a paper web, wherein the web has at least two different non-extruded regions differing in one or more of the following properties: thickness, height, density and basis weight.

A further object is to provide a paper web and a method of making a paper web wherein the web has increased caliper, bulk density and absorbency with a relatively patterned face and a relatively smooth opposite surface, thereby providing both the bulkiness and softness properties desired consumers of paper products.

It is a further object of the present invention to provide a method of making a paper web, wherein the web is a paper web and substantially free of materials. 0 0 0 0 0 0 • 00 00 0 000 0 000 00 0 000 • 0 0 0 0 000 00 0 Binder materials such as elastomeric binders which negatively affect the absorbency.

SUMMARY OF THE INVENTION

The invention encompasses a wet-laid paper web having first and second opposed faces. The paper comprises a relatively thinner region and a relatively thicker region, wherein the relatively thicker region is disposed in the plane of the relatively thinner region. The ratio of the thickness P of the relatively thicker region to the thickness K of the relatively thinner region may be at least about 1.5.

In one embodiment, the paper web comprises a relatively thinner continuous network region that may have a relatively high density and many relatively thicker discrete regions dispersed in the continuous network region. The discrete regions are located in the plane of the continuous network region and may have a density that is lower than the density of the continuous network region. In one embodiment, each relatively thicker discrete region may surround at least one discrete compacted region.

The paper web may have a basis weight ranging from about 7 to about 0

about 70 g / m < 3 > and a macro thickness of at least about 0.1 mm and more preferably at least about 0.2 mm and a bulk density of less than or equal to about 0.12 g / cm < ^{3 &gt};. The paper web may also have an absorbency of at least about 20 g / g.

The paper web may have a surface smoothness ratio greater than about 1.15, preferably greater than about 1.20, particularly preferably greater than about 1.25, even more preferably greater than 1.30, and most preferably greater than about 1.40. One surface of the strip may have a surface smoothness value of less than about 900, and more preferably less than about 850. A reverse surface of the strip may have a smoothness value

A surface area measurement of at least about 900, and more preferably at least about 1000. Methods for measuring area thickness, macro web thickness, web base weight, web bulk density, and surface smoothness ratio are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

While the description ends with claims that specifically emphasize and clearly define the invention, the invention will be better understood from the following description, which is accompanied by drawings in which like elements are designated with the same reference numeral, wherein:

Figure 1 is a plan view of a first surface of a paper material according to an embodiment of the present invention, the paper material having a first, relatively thinner continuous network region and many relatively thicker, spaced apart regions dispersed in the continuous network region.

Figure 2 shows the paper material of Figure 1 in cross section taken along lines 2-2 of Figure 1 and showing relatively thicker discrete areas located in the plane of the continuous network area.

Figure 3 is a photomicrograph of a cross-section of paper material of the type shown in Figures 1 and 2.

Figure 4 is a photograph of a first surface of a paper material of the type shown in Figures 1 and 2.

Figure 5 is a photograph of a second surface of the paper material of the type shown in Figures 1 and 2.

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Figure 6 shows a cross-section of a prior art paper of the type disclosed in U.S. Patent 4,637,859.

Figure 7A is a micrograph of a cross-section of a paper web of the type of U.S. Patent 4,637,859.

Figure 7B is a plan view of one side of the paper web of the type shown in U.S. Patent 4,637,859. Figure 7C is a plan view of the other side of the paper web of Figure 7B.

Figure 8A is a plan view of an apparatus used to produce a paper web of the type shown in Figures 1 and 2, the apparatus comprising a dewatering felt layer and a web patterning layer attached to the dewatering felt layer and having a continuous mesh web contacting the web upper surface.

Figure 8B is a cross-sectional view of the apparatus of Figure 8A taken along lines 8B shown in Figure 8A.

Figure 8C is a plan view of an apparatus comprising a dewatering felt layer and a web patterning layer, wherein the web patterning layer comprises a discrete web contacting surfaces.

Figure 9A shows a papermaking machine for producing a paper web with the apparatus of Figures 8A and 8B.

Figure 9B illustrates a paper web transferred to the apparatus shown in Figure 8B to form a paper web having a first surface substantially corresponding to the apparatus and a second substantially smooth surface.

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Figure 9C depicts a paper web on the apparatus shown in Figure 8B that is supported between a vacuum press roll and a Yankee dryer drum so as to form a pattern on a first surface of the paper web and a second surface of the paper web adjacent the Yankee.

Figure 9D is a cross-sectional view of a two-ply tissue paper comprising two webs of the type shown in Fig. 2 with relatively smoother second web surfaces facing outwards.

Figure 10 is a cross-sectional view of a web made according to an alternate embodiment of the present invention, showing relatively thicker discrete areas located in the plane of the continuous network area, and within each discrete area surrounding one or more discrete densified areas.

Figure 11 is a photomicrograph of a cross-section of the paper material of the type shown in Figure 10.

Figure 12 is a photograph of a first surface of the paper material of the type shown in Figure 10.

Figure 13 is a photograph of a second surface of the paper material of the type shown in Figure 10.

Figure 14A is a plan view of an apparatus for use in making a web of the type shown in Figure 10, the apparatus comprising a web patterning layer attached to a perforated element formed from woven fibers.

Figure 14B is a cross-sectional view of the apparatus of Figure 14.

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Figure 15Α shows a paper machine with the apparatus of Figures 14A and 14B.

for the production of a belt

Figure 15B illustrates a web of paper transferred to the apparatus shown in Figure 14B to form a paper web having a first surface corresponding to the apparatus and a second surface that is substantially smooth.

Figure 15C depicts a paper web on the apparatus shown in Figure 14B, which is supported between the pressure roll and the Yankee dryer drum so as to extrude the pattern on the first surface of the paper web and adhere the second surface of the web to the Yankee drum.

Figure 16 is a cross-sectional view of a web of paper produced in accordance with one embodiment of the present invention, wherein the web comprises a plurality of layers of fibers including a release liner.

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Figures 1 and 2 illustrate a paper web 20 made according to one embodiment of the present invention and Figures 3 to 5 are photographs of a paper structure of the type shown in Figures 1 and 2. For comparison purposes, Figures 6 and 7A to 7C show a paper web of the type is described in U.S. Patent 4,637,859.

The paper web made according to one embodiment of the present invention comprises a relatively thinner region and a relatively thicker region, wherein the relatively thicker region is located in the plane of the relatively thinner region. The paper web is wet-laid and can be substantially free of dry spots. Referring to Figures 1 to 5, the paper web 20 has a first surface 22 and a second facing surface 24.

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The paper web 20 comprises a relatively thinner region 30 having a thickness designated bordering region 30 is denoted 32 bordering region 30 is denoted 34.

Partial surface 22 and part surface 2 4

The web 20 also includes a plurality of relatively thicker regions 50 dispersed in the continuous mesh region 30. The relatively thicker regions 50 have a thickness designated P and extend from the surface 32 of the continuous network region 30. a portion of the surface 22 bordering the regions 50 is designated 52 and a portion of the surface 24 bordering regions 50 is designated 54. The thickness P is greater than the thickness K. Preferably, the P / K ratio is at least about 1.5. Referring to Figure 3, P may be at least about 0.3 mm, and preferably at least about 0.40 mm. K may be less than about 0.25 mm, and more preferably less than about 0.20 mm.

The continuous network area and the discrete, relatively thicker areas 50 may both be shortened beforehand, for example by creping. In Figures 1 and 2, the creping combs of the continuous network region are designated with the number 35 and extend generally in a cross machine direction. Separate, relatively thicker regions 50 may also similarly be shortened to have crepe combs 55.

The continuous network region 30 may be a relatively high density, macroscopically monoplanar continuous network region of the type disclosed in U.S. Patent 4,637,859. Relatively thicker regions 50 may have relatively low density and may be spaced alternately on both sides as described in U.S. Patent 4,637,859, but the relatively thicker regions 50 are not domes of the type shown in U.S. Patent 4,637,859.

The relatively thicker regions 50 are located in the plane of the continuous network region 30. The height of the plane of the network region 30 is this to this to this. This is represented schematically by the surface 23 (in figure 2 it appears as a straight line). The surface 23 is located midway between the surfaces 32 and 34. While the plane of the web 30 is shown as being flat in Figure 2, it is understood that the plane of the web 30 may include a surface 23 having a curvature.

By the expression located in the plane of the continuous network region 30 is meant that the relatively thicker region 50 includes a portion extending both above and below the surface 23. As seen in Figure 2, a portion of the thicker region 50 extends along an imaginary line 25. A portion of the region 50 extending along the imaginary line 25 is positioned both above and below the surface 23 so that the intersection of the line 25 with the surface 52 is above the surface 23 and the intersection of the line 25 with the surface 54 is below the surface 23.

The procedure for measuring the thickness P and K and the procedure for determining the location of the surface 23 to determine whether the region 50 is located in the plane of the region 30 are described below in the Measurement of Thickness and Height section.

Unlike the paper web shown in Figures 1 and 2, the paper web 80 shown in Figure 6, which is described in U.S. Patent 4,637,859, does not have relatively thicker regions located in the plane of the continuous web. U.S. Patent 4,637,859 discloses domes 84 dispersed in a continuous web 83. In Figure 6, the domes 84 are not located in the plane of the web 83. Instead, as seen in Figure 6, the bottom surface of the domes 84 is located above the surface 23 shown in Figure 6. A micrograph of a paper web of the type described in the patent USA 4,637,859, is shown in Figure 7A and the opposing surfaces of such a paper web are shown in Figures 7B and 7C.

• ·· * 9,999 ♦ 9,99 *

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99

Accordingly, the paper web 20 shown in Figures 1 and 2 may have strength advantages with the continuous mesh region 30, bulk density, macro thickness, absorbency and softness that are derived from relatively thicker regions 50 and yet have a relatively smooth surface 24 compared to paper of the type shown in U.S. Patent 4,637,859.

In particular, the paper web 20 may have a surface smoothness ratio greater than about 1.15, preferably more than about 1.20, even more preferably about 1.25, even more preferably about 1.30, and most preferably about 1.40, wherein the surface smoothness ratio is the surface smoothness value 22 divided by the surface smoothness value 24.

In one embodiment, the surface 24 of the web 20 may have a surface smoothness value of less than about 900, and more preferably less than about 850. The opposite surface 22 may have a surface smoothness value of at least about 900, and more preferably at least about 1000.

The method for measuring the surface smoothness value is described below in the Surface smoothness section. The surface smoothness value of the surface increases as the surface becomes more structured and less smooth. A relatively low surface smoothness value then results in a relatively smooth surface.

In contrast to the paper webs 20 of the present invention, the paper pattern of the type described in U.S. Patent 4,637,859 can exhibit a surface smoothness ratio of about 1.07 and a smoothness value on opposite surfaces of about 993 and 1065.

One advantage of the paper web 20 is the combination of the relatively smooth surface 24 for softness, the relatively thicker areas 50 for providing relatively high

• ·· ·· ··

bulkiness and absorbency and compacted relatively thinner, relatively high density mesh regions 30 for strength. In addition, the paper web 20 can be formed and dried relatively quickly and efficiently as described below.

A paper web 20 having a relatively smooth surface 24 may be useful in making multiple sheets of folded tissue paper having smooth outward facing surfaces. For example, two or more webs 20 may be combined to form a plurality of sheets of folded tissue paper such that the two outwardly facing surfaces of the plurality of sheets of folded tissue paper include the surfaces 24 of the sheets 20 and the surfaces 22 of the outer sheets facing inwards. Such multi-ply tissue paper may have strength and bulk benefits associated with relatively thicker areas dispersed in a continuous network area and yet present a relatively smooth and soft outer surface for the customer's touch.

An example of such a bilayer tissue paper is shown in Figure 9D. The two belts 20 may be joined together so as to be joined together in any suitable manner, including, but not limited to, gluing, mechanical and ultrasonic bonding, and combinations thereof.

The paper web 20 may have a basis weight of about 7 to about 70 g / m 2. The paper web 20 may have a macro-thickness of at least about 0.1 mm and preferably at least about 0.2 mm and a bulk density of at least about 0.12 g / cm (basis weight divided by macro-thickness). The procedures for measuring the basis weight, macro-thickness, and bulk density of the web are described below.

The paper web 20 of the type shown in Figures 1 and 2 may also have an absorbent capacity of at least about 20 g / g. The method for measuring the absorption capacity is described below. The paper web 20 has advantages in absorption capability such as the paper webs. High bulkiness in combination with the advantages of a relatively smooth surface, usually associated with conventional tissue papers, which are conventionally compressed with felt.

Belt supporting the apparatus

Figures 8A and 8B illustrate a web supporting apparatus 200 for use in making a paper web of the type shown in Figures 1 and 2. The web supporting apparatus 200 includes a dewatering felt layer 20 and a pattern web, layer 2.50. in the form of a continuous web for drying and supplying the pattern of the web in a paper machine. The belt supporting the apparatus 200 has a first belt face 202 and a second side 204 facing the opposite side. The belt supporting the apparatus 200 is shown in Figure 8A with the first side facing the belt 202 toward the viewer. The first belt-facing side 202 includes a first surface in contact with the belt and a second surface in contact with the belt.

In Figures 8A and 8B, the first web contacting surface is a first felt surface 230 of the felt layer 220. The first felt surface 230 is positioned at a first height 231 The first felt surface 230 is a felt surface in contact with the web. The felt layer 220 also has a second felt surface 232 facing away from it.

In Figures 8A and 8B, the second contacting surface is provided with a web pattern 250. The web pattern 250, which is attached to the felt layer 220, has a web contacting the top surface 260 at a second height 261. The difference between the first height 231 and the second the height of 2 61 is less than the thickness of the paper web when the paper web is converted to a web supporting the apparatus 200. Surfaces 260 and 230 can be placed in the web. · · · ··· ·· ····· · · · · · · · · · · · · Same height, so heights 231 and 261 are the same. Alternatively, surface 260 may be slightly above surface 230 or surface 230 may be slightly above surface 260.

The height difference is greater than or equal to 0.0 miles and less than about 8.0 miles (0.20 mm). In one embodiment, the height difference is less than about 6.0 mil (0.15 mm), more preferably less than about 4.0 mil (0.10 mm) and most preferably less than about 2.0 mil (0.05 mm) to maintain a relatively smooth surface 24 as described below.

The dewatering felt layer 220 is permeable. is capable of receiving and containing water extruded from a wet web of paper-forming fibers. The web patterning layer 250 is impermeable to water and neither accepts nor contains water displaced from the web by the paper forming fibers. The web patterning layer 250 may have a continuous top surface 260 that is in contact with the web as shown in Figure 8A. Alternatively, the strip pattern layer may be discontinuous or semi-continuous. The discontinuous topsheet 260 is shown in Figure 8C.

The web pattern 250 preferably includes a photosensitive resin that may be deposited on the first surface 230 as a liquid and subsequently crosslinked by radiation such that a portion of the web pattern 250 penetrates and is thereby securely attached to the first felt surface 230. it does not extend through the entire thickness of the felt layer 220, but instead extends to less than about half the thickness of the felt layer 220 to maintain the flexibility and compressibility of the web supporting apparatus 200, and in particular the flexibility and compressibility of the felt layer 220.

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A suitable dewatering felt layer 220 comprises a nonwoven web 240 of natural or synthetic fibers joined by needling into a carrier material formed from woven fibers 244. Suitable materials from which a nonwoven web can be formed may include, but are not limited to, natural fibers such as wool and synthetic fibers such as polyester and nylon. The fibers of which the web 240 is formed may have a denier of between about 3 and about 20 grams per 9,000 meters of fiber length.

The felt layer 220 may have a layered construction and may include a mixture of fiber types and sizes. The felt layer 220 is formed to assist transport of water received from the web away from the first felt surface 230 and towards the second felt surface 232. The felt layer 220 may have finer, relatively more densely compressed fibers disposed adjacent the first felt surface 230. The felt layer 220 preferably, it has a relatively high density and a relatively small pore size near the first felt surface 230 compared to the density and pore size of the felt layer 220 at the second felt surface 232, so that water entering the first surface 230 is carried away from the first surface 230.

The dewatering felt layer 220 may have a thickness greater than about 2 mm. In one embodiment, the dewatering felt layer 220 may have a thickness ranging from about 2 mm to about 5 mm.

PCT publications WO 96/00812 published January 11, 1996, WO 96/22555, published August 22, 1996 and WO 96/25547 published August 22, 1996, all in the name of Trokhan et al., US patent application 08/701 600 papermaking material filed Aug. 22, 1996, US Patent Application 08/640 452 High Absorbency / Low Reflectance of Felt with Pattern Layer Filed April 30, 1996 and US Patent Application 08/672 293 Method

- 17 * «« • 4 · • 444 9 4 4 4 4 4 4 949 49 49 4449 4 4 4 4 • 44 4 4 4 9 4 4 4 4 49 4 49 4 4 4 44 4 • 4 4 9 · 4 • 9 94 94 wet production extruded silk of paper with felt having selected them permeability, filed on 28. June 1996 se hereby include by reference for purpose description use

photosensitive resins for dewatering felt and for describing suitable dewatering felt.

The dewatering felt layer 220 may have an air permeability of less than about 200 normal cubic feet per minute (scfm) (60.96 Nm / min am), wherein the scfm air permeability is a measure of the number of cubic feet of air per minute that pass through an area of one square feet (0.093 m ² ) of the felt layer at a pressure difference across a dewatering felt thickness of about 0.5 inch (1.34 mm) of water column. In one embodiment, the dewatering felt layer 220 may have an air permeability in the range of about 5 to about 200 scfm (1.52 to 60, 96 Nm ³ / min am ² ), preferably less than about 100 scfm (30.48 Nm ^J). / min and ² ).

The dewatering felt layer 220 may have a basis weight comprised between about 800 and about 2000 g / m ² , an average density (basis weight divided by thickness) comprised between about 0.35 g / cm and about 0.45 g / cm. The air permeability of the web support apparatus 200 is less than or equal to the permeability of the felt layer 220.

One suitable felt layer 220 is Amflex 2 Press Felt manufactured by Appleton Mills Company, Appleton, Wisconsin, USA. The felt layer 220 is an Amflex 2 molded felt manufactured by Appleton Mills Company, Appleton, Wisconsin, USA. The felt layer 220 may have a thickness of about 3 mm, a basis weight of about 1400 g / m ² , an air permeability of about 30 scfm (9.14).

Nm ^J / min and ² ) and have a bilayer support structure having a three-ply or more fiber top and a warp bottom and a four-ply cable monofilament weft across the machine. The web 240 may include polyester fibers having a denier of about 3 on the first 9 9 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99

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99 99 of the surface 230 and the denier between 10 and 15 in the nonwoven substrate which lies below the first surface 230.

The belt support apparatus 200 shown in Figure 8A has a belt pattern layer 250 having a continuous mesh top surface 260 that is in contact with the belt having a plurality of discrete apertures 270. Suitable aperture shapes 270 include, but are not limited to, ovals elongated in the machine direction (designated MD in Figure 8A), polygons, irregular shapes, or mixtures thereof. The projected surface area of the continuous top net surface 260 may range from about 5 to about 75 percent of the projected area of the web supporting apparatus 200 as shown in Figure 8Ά and is preferably between about 25 percent and about 50 percent of the projected area of apparatus 200.

In the embodiment illustrated in Figure 8a, the continuous topsheet surface 26 may have less than about 700 spaced apart holes per square inch (109 / cm ² ) of the projected area of the apparatus 200, and preferably about 10 to about 400 spaced holes 270 per square inch. 1.5 to 62 (cm 2) of the projected area of the apparatus as shown in Figure 8A. The spaced apart apertures 270 may be bilaterally spaced alternately zigzag in the machine direction (MD) and across the machine (CD) direction as described in U.S. Patent 4,637,859, issued January 20, 1987. In one embodiment, the apertures may be 270 overlapping and bilaterally spaced zigzag with holes of a size and pitch such that both machine and transverse machine directions engage the edges of the holes 270 so that each line drawn parallel to or along the machine direction across the machine will pass through at least some of the apertures 270.

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Description of paper production method

The paper material 20 of the present invention can be manufactured on the paper machine shown in Figures 9A, 9B and 9C. Referring to Figure 9A, the method of making paper web 20 of the present invention is initiated by taking a water dispersion of paper forming fibers in the form of a paper slurry and placing it from the headbox 500 onto a perforated liquid pervious forming member such as a forming belt 542. followed by forming the seed web of paper forming fibers 543, which are supported by the forming belt 542. For simplicity, the forming belt is shown as a single Fourdrinier sieve. It will be understood that each of the various double forming sieves may also be used.

It is contemplated that the fiber-forming paper used in the present invention may be fibreboard paper pulp in all kinds thereof. However, other cellulosic fibrous paper pastes such as cotton, bagasse, rayon, etc. may also be used and none are excluded. Wood pulp materials which may be used herein include chemical paper pulps such as Kraft Kraft Paper Kraft, Kraft and Kraft Paper Mashes, as well as mechanical paper mashes including, for example, ground wood, thermomechanical paper mashes and chemical thermomechanical paper mashes (CTMP). Paper mash from both deciduous and coniferous trees can be used.

Both hardwood pulp and softwood pulp as well as mixtures of both can be used. The term hardwood paper mash as used herein refers to fibrous paper mash derived from angiosperms, while softwood paper mash is fibrous paper mash derived from:

- 20 species of coniferous trees (gymnosperms). Hardwood paper slurries such as eucalyptus having an average fiber length of about 1.00 mm are particularly suitable for tissue paper strips, which are further described where softness is important, while Northern Softwood Kraft softwood kraft having an average fiber length about 2.5 mm are preferred where strength is required. Also useful in the present invention are fibers derived from recycled paper, which may include any or all of the above categories, as well as other non-fibrous materials such as fillers and adhesives used to facilitate the original paper making.

The paper coating may include a number of additives, including but not limited to fibrous binder materials such as wet strength binder materials, dry strength binder materials, and chemical softening compounds. Suitable wet strength binders include, but are not limited to, materials such as polyamide-epichlorohydrin resins sold under the tradename KYMENE® 557H from Hercules Inc., Wilmington, Delaware, USA. Suitable temporary wet strength binders include, but are not limited to, modified starch binders such as NATIONAL STARCH® 78-0080, sold by National Starch Chemical Corporation, New York, New York, USA. Suitable dry strength binders include materials such as carboxymethylcellulose and cationic polymers such as ACCO® 711. The xACCO® dry strength group of materials is available from the American Cvanamid Company. Wavne, New Jersey, USA.

The paper deposit deposited on the forming screen preferably comprises a bonding interfering agent to inhibit some fiber-to-fiber bonds as the web is dried. The bonding interfering agent, in combination with the energy supplied to the web by the dry creping process, results in a portion of the web being compacted. In one embodiment, • fefe • · fefefefe fe • ·

a bonding interfering agent is applied to the fibers forming the intervening layer of fibers interposed between two or more layers. The intermediate layer acts as a bonding layer between the outer layers of fibers. The creping energy may therefore lead to the loosening of a portion between the outer layers of fibers. The creping energy can therefore compact a portion of the strip along the bond removal layer. The loosening of the belt can lead to cavities 310 (Figure 16).

As a result, the web can be formed to have a relatively smooth surface for efficient drying on a Yankee drying drum. However, due to compaction on the creping blade, the dried web may also have regions of varying density, including a continuous mesh-like relatively high-density region and discrete relatively low-density regions that are formed by the creping process.

Suitable bond disrupters include chemical softeners such as those described in U.S. Patent 5,279,967, issued Jan. 18, 1994 to Phan et al. Suitable biodegradable chemical softeners are described in U.S. Patent 5,312,522, issued May 17, 1994 to Phan et al. U.S. Patents 5,279,767 and 5,312,522 are hereby incorporated by reference. Such chemical softeners can be used as bonding disrupting agents to break the bonds between the fibers in one or more layers of the fiber forming fibers.

One suitable emollient to provide fiber-bond disruption in one or more layers of fibers forming the web 20 is a papermaking additive comprising diester-di (cured) thallium dimethylammonium chloride. A suitable plasticizer used in the papermaking industry is the branded ADOGEN® additive sold by Witco Company, Greenwich, CT, USA.

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Μ ·· ··

The embryonic web 543 is preferably prepared from an aqueous dispersion of paper-forming fibers, although dispersions in liquids other than water may also be used. The fibers are dispersed in the carrier liquid to have a consistency of from about 0.1 to about 0.3 percent. The percent consistency of a dispersion, slurry, web, or other system is defined as 100 times the coefficient obtained when the weight of dry fibers in the system under consideration is divided by the total weight of the system. The fiber weight is always expressed on the basis of completely dry fibers.

The embryonic web 543 may be formed in a continuous papermaking process, as shown in Figure 9A, or alternatively in a batch process such as manual papermaking. After the dispersion of the fiber forming paper is deposited on the forming belt 542, the seed belt 543 is formed by removing a portion of the aqueous dispersing medium by methods well known to those skilled in the art. The embryonic web is generally monoplanar and is formed to have a substantially smooth, macroscopically monoplanar first and second surfaces using any suitable forming web 542.

Vacuum boxes, forming plates, hydrophilic films, etc. can be used to remove water from the dispersion. The embryonic web 543 moves along with the forming web 542 around the return cylinder 502 and comes near the web supporting apparatus 200.

The next step in manufacturing the embryonic web 54 3 of supporting the transferred paper material 20 comprises transferring from the forming web 542 to the apparatus 200 and the web (designated by the number 545 in the figure).

9B) on the first side 202 of the apparatus 200. Preferably, the germline at the transition point to the apparatus 200 has a consistency ranging from about to about 20 percent.

The web is transferred to the apparatus 200 such that the first face side 547 of the web 545 is supported and follows the surface 202 of the apparatus 200 with portions of the web 545 supported on the surface 260 and portions of the web supported on the felt surface 230. smooth, macroscopically monoplanar configuration. Referring to Figure 9B, the height difference between the surface 260 and the surface 230 of the belt support apparatus 200 is small enough that the other back side of the germline remains substantially smooth and macroscopically monoplanar when the belt is transferred to the apparatus 200. and the surface 230 should be less than the germline thickness at the transfer point.

The steps of transferring the germline 543 to the apparatus 200 may be provided at least in part by applying a liquid pressure difference to the germline 543. For example, the germline 543 may be a vacuum transferred from the forming belt 542 to the apparatus 200 by the vacuum source 600 shown in Figure 9A. such as a vacuum foot or vacuum cylinder. One or more additional vacuum sources 620 may also be provided beyond the germline transfer point to provide further drainage.

The belt 545 is supported on the machine 200 in the machine direction (MD in Figure 9A) to the gap 800 existing between the vacuum press roll 900 and the hard surface 875 of the heated drying drum Yankee 880. Referring to Figure 9C, The steam hood 2800 directs steam directly to the surface 54 9 of the belt 545 as the surface 54 7 of the belt 545 is transferred through the vacuum providing the portion 920 of the vacuum press roller 900.

The steam hood 2800 is mounted opposite the vacuum providing portion 920. The vacuum providing portion 920 draws the steam into the web 54 5 and the felt layer 220. The steam provided by the steam hood 2800

Heats the water in the paper web 545 and the felt layer 220, thereby reducing the viscosity of the water in the web and the felt layer 220 This makes the water in the web and the felt layer 220 more easily removed by the vacuum provided by the roller 900.

The steam hatch 2800 can provide about 0.3 pounds (0.14 kg) of saturated steam per pound (0.45 kg) of dry fibers at a pressure of less than about 15 psi (0.1 MPa). The vacuum providing portion 920 provides a vacuum on the surface 204 of from about 1 to about 15 inches (25.4 to 381 mm) of mercury column, and preferably from about 3 to about 12 inches (76 to 305 mm) of mercury column. A suitable vacuum pressure roller 900 is a suction pressure roller manufactured by Winchester Roli Products. A suitable steam hood 2800 is a type D5A manufactured by Measurex-Devron Company of North Vancouver, British Columbia, Canada.

The vacuum securing portion 920 is in communication with a vacuum source (not shown). The vacuum securing portion 920 is stationary to the rotating surface 910 of the cylinder 900. The surface 910 may be a drilled or grooved surface over which a vacuum is applied to the surface 204. The surface 910 rotates in the direction shown in Figure 9C. The vacuum providing portion 920 provides vacuum on the surface 204 of the belt supporting apparatus 200 as the belt and apparatus 200 are carried through the steam hood 2800 and through the gap 800. While only the vacuum portion 920 is shown, in other embodiments it may be desirable to provide separate vacuum securing parts each providing a different vacuum on the surface 204 as the apparatus 200 passes around the cylinder 900.

The Yankee drying drum typically comprises a steam-heated steel or iron drum. Referring to Figure 9C, the belt 545 is carried into the gap 800 on the apparatus 200 so that a substantially smooth second belt surface 549 can be transferred to the surface 875. Before the belt is moved, the belt 545 is supported.

- 25 99 99 • 9 4 • 9 I 9 9 9 9 4

4> 99 gap, before the point where the web is transferred to the surface 875 of the nozzle 890, applies adhesive to the surface 875.

The adhesive may be a polyvinyl alcohol based adhesive. Alternatively, the adhesive may be a CREPTROL® adhesive manufactured by Hercules Company, Wilmington, Delaware, USA. Other adhesives may also be used. Generally, in an embodiment where the belt is transferred to a Yankee 880 drying drum at a consistency of greater than about 40

percent grey Use glue as CREPTROL® adhesive. Adhesive can be applied on the belt directly or indirectly row ways (as this is the case with application on the drying surface drum Yankee 875). For example, it can be glue sprayed onto belt in

microencapsulated or Yankee 875 drying drum surface. Alternatively, the adhesive could also be applied to the surface 875 with a roll or brush. In yet another embodiment, a creping adhesive could be added to the paper deposition at the wet end of the paper machine, for example by adding the adhesive to the paper deposition in the headbox 500. The Yankee 880 drying drum can be applied from about 2 pounds per ton of dried paper fibers. into about 4 pounds of adhesive.

900

As the belt is supported on the apparatus 200 through the gap 800, the vacuum providing portion 920 of the roller 900 provides a vacuum on the surface 204 of the belt carrying the apparatus 200. Like the belt is supported on the apparatus 200 through the gap 800 between the vacuum press roll the belt supporting apparatus 200 pushes into it a pattern corresponding to the surface 260 of the first surface 547 of the belt 545. Since the second back surface 549 is a substantially smooth, macroscopically monoplanar surface, substantially the entire second surface 549 is positioned against and adheres to the dryer surface 875 as the belt carried through the gap 800. As the belt is carried through the gap, the second surface 549 is supported on the smooth surface 875 to maintain the

9999

9

98 «9 9

9 9

999 999

9

99 smooth, macroscopically monoplanar. Accordingly, the first surface 547 of the belt 545 is provided with a preselected pattern, while the second surface 549 remains substantially smooth. The web 545 preferably has a consistency ranging from about 20 percent to about 60 percent when the web 545 is transferred to the surface 875 and a surface pattern 260 is formed on the web.

As the belt is carried through the gap 800, it is believed that the heated surface 875 can heat the water in the belt 545 to boil. It is believed that the vacuum generated by the vacuum pressure roller 900 sucks boiling water from the belt through portions of the felt layer 220 not covered. 250 extruded into the belt.

Without being limited by theory, it is believed that as a result of substantially the entire second surface 549 being positioned against the Yankee drum surface 875, drying the belt 545 on the Yankee drying drum is more efficient than would be possible with a belt having only selected portions of the second surface against the Yankee drying drum. In particular, it is believed that by placing substantially the entire second surface 549 against the surface of the Yankee 875, the patterned paper described above having both bulkiness and smoothness and having a basis weight of at least about 8 lbs (3.6 kg) per 3000 square feet (27,9 m ² ) and preferably at least about 10 lbs (4.5 kg) per 3000 square feet (279 m ² ) may be dried on a Yankee 880 drying drum from a consistency of at least about 50 percent and preferably less than 30 percent to a consistency of at least about 90 percent and still more. more preferably at least about 95 percent, at removal of water at a rate of at least about 11 tons of water per hour at a belt speed of at least about 4500 feet (1372 m) / minute, and more preferably at least about 5000 feet (1524 m) / minute.

In particular, it is contemplated that the present invention allows the belt 545 to have a basis weight of at least about 8 pounds (3.6 kg) per 3000 square feet (279 m) and preferably at least about 10 pounds (4.5 pounds). fcfc fcfc fcfc c fcfc * fcfc * fcfc * fcfc * fcfc * fcfc * fcfc * fcfc * fcfc) fcfc * fcfc * fcfc) fcfc * kg) to 3000 square feet (279 m) to dry from relatively low consistency to relatively high a consistency on the Yankee dryer drum at a drum speed of at least about 4500 feet (1372 m) per minute. In particular, it is contemplated that the present invention allows web 545 to have the above basis weight parameters to be dried from a consistency of less than about 30 percent and preferably more than about 25 percent (when the web is transferred to the drum 880) to a consistency of at least about 90 percent. percent and more preferably at least about 95 percent (when the strip is removed from the drum by creping) at a belt speed of at least about 4500 feet (1372 m) per minute, more preferably at least about 5000 feet (1524 m) per minute, and most preferably at least about 6000 feet (1829 m) ) per minute on the Yankee drying drum.

In comparison, it is believed that the drying rate of the paper on a Yankee drying drum having a continuous mesh and discrete domes as described in U.S. Patent 4,637,859 and a basis weight of at least about 10 pounds (4.5 kg) per 3,000 square feet ( 279 m ² ) cannot be as high as 3500 ft / min (1067 m / min) if the Yankee drum is to be dried from about 30 percent to about 90 percent consistency. The paper of the type shown in U.S. Pat. No. 4,637,859 is typically pre-dried before the Yankee drum to have a consistency of about 60 percent to about 70 percent upon transition to the drying drum. Without being limited by theory, it is believed that if the paper shown in U.S. Patent 4,637,859 is dried without using a pre-dryer, then the Yankee dryer drum speed is limited to less than about 3000 feet / min (914 m / min).

The final step in forming the paper structure 20 is to crepe the web 545 with the surface 875 using a scraper blade 1000 as shown in Figure 9A. Without being limited by theory, it is believed that the energy supplied by the scraper blade 1000 of the belt 545 increases volume or removes compaction.

(B)

- 28 ··············································· At least some portions of the web, particularly those portions of the web on which the web pattern surface 260 is not embossed. Accordingly, the creping step of the web with the surface 875 of the scraper blade 1000 ensures that the web has a first, densified, relatively thinner region corresponding to the pattern provided to the first face of the web and a second relatively thicker region. Generally, the scraper blade has a bevel angle of about 25 degrees and is positioned relative to the Yankee dryer drum to provide a cutting angle of about 81 degrees.

The paper material 20 shown in Figure 2 exhibits a shortening due to creping in both the continuous region 30 and the discrete regions 50. The creping frequency in the region 30 is different than that in the regions 50. Generally the creping frequency in the regions 50 is lower than the creping frequency in the continuous network 30.

In an alternative embodiment, the web embossing apparatus 200 may include a resin pattern layer 250 that defines a plurality of discrete raised surfaces 260 in contact with the web that are bonded to the dewatering felt layer 220 as shown in plan view of Figure 8C. . In Figure 8C, the felt surface 230 that is in contact with the waist is in the form of a continuous siue.

That surrounds discrete surfaces 260. Such an apparatus can be used to form a paper web according to the present invention, wherein the paper material includes many relatively thinner discrete regions that are dispersed in a relatively thicker continuous network region.

0 · 00 · 0 0 0 0 ♦ 4 0 0

0 · · 000 004

- 29 0 · '* * * * * 29 29 29

In another alternative embodiment of the present invention, the belt supporting the apparatus 200 may include a resin layer disposed on a background perforated member that includes a woven fiber fabric. Referring to Figures 14A-15C, the apparatus 200 may include a resin layer 250 disposed on the woven fabric 1220.

The resin layer 250 has a continuous mesh web contacting surface 260 defining discrete apertures 270 as shown in Figure 14A. The woven fabric 1220 includes fibers 1242 extending along the machine and fibers 1241 extending across the machine.

In Figures 14A and 14B, the first surface in contact with the belt at a first height 1231 is provided with discrete bump surfaces 1230 located at the intersection point of the fibers 1241 and 1242. The upper surfaces of the fibers 1241 and 1242 may be sandblasted or otherwise ground to provide the relatively flat, generally oval shaped bumps surfaces 1230 (detail of the oval shapes not shown in Figure 14A). The second surface in contact with the web is provided with a web 250 patterning the web. The pattern patterning web 250 that is bonded to the woven fabric 1220 has an upper surface 26 that contacts the web at a second height.

261.

The difference between the first height 1231 and the second height 26 is less than roughly the thickness of the paper web when the paper web is transferred to the web supporting the apparatus 200. Continuous surface 260 and tttt tt ttt tttt * ♦ tt * tttt tt tttt ♦ »♦ ♦

tt tttt tttt discrete surfaces 1230 may be positioned at the same height, so that the heights 1231 and 261 are the same. Alternatively, the surface 260 may be slightly above the surfaces 1230 or the surfaces 1230 may be slightly above the surface 260.

The height difference is greater than or equal to 0.0 miles and less than about 5.0 miles. In one embodiment, the height difference is less than about 4.0 miles (0.10 mm), more preferably less than about 2.0 miles. (0.05 mm) and most preferably less than about 1.0 mil (0.025 mm) to maintain a relatively smooth surface 24 as described below.

The belt supporting the apparatus 200 shown in Figures 14A and 14B may be used to form the paper web shown in Figures 10 to 13. Referring to Figure 10, the paper web 20 comprises a continuous network, a relatively thinner region 30 corresponding to surface 60 and a plurality of discrete relatively thicker regions. 50 dispersed in the continuous network region 30. The regions 50 correspond to apertures 270 in the surface 260. Each of the relatively thicker regions 50 surrounds at least one compacted region.

70. The compacted regions 70 correspond to the surfaces 1230 of the woven fabric

1220.

Referring to Figure 11, P may be at least about 0.35 mm, and preferably at least about 0.44 mm. K may be less than about 0.20 mm, and more preferably less than about 0.10 mm.

• • • • • • • • • • •

Figures 15A to 15C illustrate the formation of the belt 20 shown in Figure 10 using the belt supporting apparatus 200. As described above with respect to Figures 9A to 9C, the germline belt

543 having first and second smooth surfaces is formed on the forming screen 542 and is transferred to the belt supporting apparatus 200. The belt 543 is vacuum transferred to the apparatus 200 to achieve belt 545 supported on the apparatus 200. As seen in Figure 15B, the first surface 547 formed according to surface 260 and surfaces 1230 and the second surface 549 is maintained as a substantially smooth, macroscopically monoplanar surface.

In contrast to Figures 9A-9C, the belt 545 and the belt supporting the apparatus 200 are then carried through the drying apparatus 650 with the air passing through, the heated air being directed across the belt 545 while the belt 545 is supported on the apparatus 200.

The heated air is directed to enter the surface 545 and pass through the belt 545 and then through the apparatus 200.

Cross-air drying apparatus 650 can be used to dry web 545 to a consistency of from about 30 percent to about 70 percent. U.S. Patent 3,303,576 issued to Sisson and U.S. Pat

247,930, issued to Ensign et al. are hereby incorporated by reference for the purpose of showing suitable cross-air dryers for use in practicing the present invention.

• flfl flflfl · flflfl flfl flfl flfl flfl flfl flfl fl fll fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl fl

fl • flfl «

flfl

The partially dried web 54 and the apparatus 200 are directed to pass through a gap 800 formed between the pressure roller 900 and the Yankee 880 drying drum. The adhesive supplied by the nozzle 890 is used to adhere substantially all of the substantially smooth surface 549 to the surface 875 of the Yankee 880 heated drying drum.

Figure 16 is a cross-sectional view of a paper web 20 showing a paper web in an embodiment of the invention, wherein the paper web has three fiber layers designated 301, 302 and 303. A paper web having a layered structure can be manufactured using the paper making apparatus and methods shown in the figures. 8A and 8B and 9A to 9C or alternatively those shown in Figures 14A, 14B and 15A to 15C.

While the individual forming screen 542 is shown in the figure

9A, it is understood that other configurations of the forming screen can be used in combination with one or more headboxes having the ability to give one or more layers of fiber deposit to obtain a multi-layer web. U.S. Patent 3,994,771 issued to Morgan et al. and U.S. Patent 4,300,981 issued

Carstens et al. and U.S. joint patent application

Layered tissue paper having improved functional properties filed October 24, 1996 in the names of Phan and Trokhan describes φ

φφφ φ

• Φ φφφφ

* φφφφ • φφφ φφφ φ φ layering and is incorporated herein by reference. Various types of forming sieve configurations including double forming sieve can be used. Furthermore, different types of headbox construction can be used to obtain a belt having one or more layers of fibers.

Referring to Figure 16, one or more headboxes may be used to form three deposition layers corresponding to layers 30, 302 and 303 on the forming screen 542, such that the seed belt comprises layers 301, 302, and 303. The first layer 301 may include relatively long layers. paper-forming fibers positioned adjacent the first surface 22 of the web. The relatively long fiber-forming paper in the first layer 301 may include softwood fibers, such as northern softwood fibers, having an average fiber length of about 3 mm or more. The second layer 302 may include a relatively short fiber forming paper positioned adjacent the second web surface 24. The relatively short fiber forming paper in the second layer 302 may include hardwood fibers such as eucalyptus fibers having an average fiber length of about 1.5 mm or less.

The third layer 303 is disposed between the first layer 301 and the second layer 302. The third layer may be a bonding layer characterized by having voids 310 that are substantially free of fibers. These voids are shown in the photomicrographs of Figures 3 and 11.

· · · · · · * * * * * * * * * * * * * * * * * * * * * * * * · «

···

In particular, voids may be located in relatively thicker regions 50. The third layer may comprise a debonding agent such as an ADOGEN® additive to reduce fiber to fiber bonding in the third layer 303, thereby facilitating the opening of the fiber structure in the layer 303 to secure empty spaces

310. The third layer 303 may comprise softwood or hardwood fibers or a combination of hardwood and softwood.

In another embodiment, each of the layers 301 and 302 may comprise relatively short hardwood fibers, and the third layer 303 may comprise relatively long softwood fibers.

For example, the layers 301 and 302 may be predominantly formed from eucalyptus fibers, and the third layer 303 may be predominantly formed from relatively long Northern Softwood fibers.

Alternatively, other methods may be used to facilitate reducing compaction of the strip or to remove fiber bonds in the middle layer of the strip. U.S. Patent 4,225,382 to Kearney et al. is hereby incorporated herein by reference for the purpose of describing multi-layer webs consisting of well bonded layers separated by an inner layer.

• · ·················

Examples

All percentages are by weight based on dry fiber weight unless otherwise indicated.

Example 1

This example illustrates the preparation of a three-ply tissue paper web made with a paper machine as shown in Figures 14A, 14B and 15A to 15C.

A 3% (by weight) aqueous Kraft Kraft Kraft Softwood Nash (Northern Softwood Kraft) is prepared in a conventional fiberizing machine. A 2% by weight aqueous wet strength resin solution (i.e., National Starch 78-0080 sold by National Starch and Chemical Corporation of New York, NY) is added to the feed pipe at NSK at a rate of 0.2% by weight based on dry fiber weight (the ratio of wet strength resin to dry fiber weight is 0.002). The NSK slurry is diluted to about 0.2% consistency of the centrifugal pump. Second, a 3% by weight aqueous paper slurry of eucalyptus fibers is prepared in a conventional fiberizing machine. A 2% by weight solution of the debonding agent (i.e., ADOGEN®442) is added to the eucalyptus feed tube at a rate of 0.1% by weight of dry fibers. The eucalyptus slurry is diluted to a consistency of about 0.2% at the centrifugal pump.

The three individually treated streams for each layer (stream 1 = 100% NSK, stream 2 = 100% eucalyptus, stream 3 = 100% eucalyptus) are held separately as they pass through the headbox and deposited on a Fourdrinier screen to form a three-layer a germline comprising two outer eucalyptus layers and a central NSK layer. Drainage occurs • · • • · · · · · φ φ φ φ φ φ φ φ φ φ φ φ φ φ φ • φ φ φ · · · φ φ φ φ φφφ • φ φ φ φ φ · on Fourdrinier sieve and is assisted by deflector and vacuum cabinets. The Fourdrinier screen has a 5-shed, satin, woven configuration and has a machine-direction 110 and a machine-direction 95 fibers per inch.

The embryonic paper web is transferred by vacuum from a Fourdrinier screen, at a fiber consistency of about 8% y transfer point, to the web supporting apparatus 200 having a perforated backing member comprising a woven fabric 1220 and a layer patterning web 250 made of photosensitive resin. Transfer of the web to the web supporting apparatus 200 is accomplished by a pressure differential of about 16 inches (406.4 mm) of mercury column. The apertured backing is configured as a 5-shed satin fabric having a machine direction 68 and a machine direction 51 monofilament per inch, the machine direction fibers having a diameter of about 0.22 mm and the machine direction fibers having a diameter of about 0.22 mm. 0.29 mm. Such an apertured backing member is manufactured by Appleton Wire Company, Appleton, Wisconsin, USA.

The web patterning layer 250 has a continuous web surface 260 in contact with the web with a projecting surface that is in the range of about 30 to about 40 percent of the projecting region of the apparatus 200. The difference between the elevation 1231 of the web that is in contact with the web and the height 261 of the continuous web surface 260 in contact with the web is about 0.001 inch (0.0254 mm).

The belt is transferred to the apparatus 20 to obtain a belt 54 5 supported on the apparatus 200 and having a substantially smooth second surface 549 as shown in Figure 15B. Further dewatering is achieved by vacuum-assisted dewatering and through-air drying as represented by the devices 600, 620 and 650 until the web has a fiber consistency of about 65%.

Fc fc fcfcfc fcfcfc fcfcfc fcfcfc fcfcfc fcfcfc fcfcfc fcfcfc fc fcfc

Transfer to the Yankee dryer drum at gap 800 is accomplished by the pressure roller 900. The surface 250 and surfaces 1230 are embossed on the first surface 547 of the belt 545 to secure the patterned surface 547. Essentially the entire second surface 549 adheres to the surface 875 of the Yankee drying drum 880 using a creping adhesive based on polyvinyl alcohol. The pressure in the gap 800 is at least about 400 pli (10.7 kg / linear cm).

Prior to dry-creping the web with the 875 surface with a scraper blade 1000, the web consistency is increased to about 90% to about 100%. The scraper blade has a bevel of about 25 degrees and is positioned with respect to the Yankee dryer drum to provide a cutting angle of about 81 degrees. The Yankee dryer drum is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is rolled into a roll at a speed of 650 fpm (200 meters per minute).

The web produced by the above process is converted into a single tissue toilet paper having three layers. The single-leaf toilet tissue has a basis weight of about 17.5 pounds per 3,000 square feet, contains about 0.02% by weight of the temporary wet strength resin and about 0.01% by weight of the jamming agent.

It is important to absorb the mono-sheet that the resulting mono-tissue tissue paper is and suitable for use as toilet tissue has the following soft paper characteristics:

base weight: 1-7 C 1 / f lb / 3000 sq ft. (28 Macro thickness: 13, 6 miles (0, 0136 inches = Volume density: 0.08 g / crn ³ surface smoothness 22 : 8 90 surface smoothness 24 : 1071 3 smoothness ratio: 1.20

• fc • fc • fcfc • fcfc • fcfc • fcfc

Example 2

This example provides a two-ply tissue paper web produced on the paper machine shown in Figures 14A, 14B and 15A-15C.

A 3% by weight NSK (Northern Softwood Kraft) aqueous kraft paper slurry is produced in a conventional fiberizing machine. A 2% temporary wet strength resin solution (e.g., PAREZ® 750 sold by the American Cyanamid Company, Stanford, Ct.) Is added to the feed pipe for NSK at a rate of 0.2% by weight based on dry fibers. The NSK paper slurry is diluted to about 0.2% density at the centrifugal pump. A second 3 wt.% Aqueous eucalyptus fiber slurry is prepared in a conventional fiberizing machine. A 2% interfering agent binding solution (ie ADOGEN® 442 sold by Witco Corporation, Dublin, OH, USA) is added to the eucalyptus slurry inlet tube at a rate of 0.1% by weight of dry fibers. The eucalyptus slurry is diluted to a consistency of about 0.2% at the centrifugal pump.

The streams of two deposition layers (stream 1 = 100 NSK / stream 2 = 100% eucalyptus) are mixed in a headbox and deposited on a Fourdrinier sieve 542 to form a seed band comprising NSK and eucalyptus fibers. Drainage takes place through a Fourdrinier screen and is assisted by a deflector and vacuum housings. The Fourdrinier screen is comprised of a 5-shed satin fabric having a machine direction 95 and a machine direction 95 monofilament per inch.

The embryonic wet web is transferred from a Fourdrinier sieve at a fiber consistency of about 8% at the point of transfer to a web supporting the web. Apparatus 200 comprising a woven fabric 1220 and a belt patterning layer 250 having a continuous mesh-like surface 260

The embryonic wet web is transferred from a Fourdrinier web at a fiber consistency of about 8% at the transfer point to the apparatus 200 to provide a web 545 having a substantially smooth, macroscopically monoplanar surface 549 and a surface 547 corresponding to surfaces 1230 and surface 260. a pressure difference of about 16 inches of mercury is used for apparatus 200. The woven fabric 1220 is of a three shed satin woven configuration having machine direction 79 and machine direction 67 monofilament fibers per inch, the machine direction fibers having a diameter of about 0.18 mm and the transverse fibers having a diameter of about 0.21 mm. Such an apertured backing member is manufactured by Appleton Wire Company, Appleton, Wisconsin.

The belt patterning layer 250 has an upper belt contact surface 260 having a projecting surface that is in the range of about 30 to about 40% of the projecting surface of the apparatus 200. The difference between the elevation 1231 of the surface 1230 in contact with the web and the elevation 2 61 of the surface 260 is about 1 mil (0.001 inches).

Further dewatering of the belt 545 is accomplished by a vacuum assisted by dewatering and through the drying air passing through the apparatuses 600, 620 and 650 until the web has a fiber consistency of about 65%. Transfer to the Yankee dryer drum occurs at a gap 800 formed between the pressure roller 900 and the Yankee 880 drying drum.

Surface 250 and surfaces 1230 are embossed into a first surface 547 of the belt 545 to form a patterned surface 547. Essentially, the entire second surface 549 adheres to the surface 875 of the Yankee dryer drum

880 using creping adhesive based on • ··

4 η ··· ♦ ·· · - 4 ν - ··· ·· · · · · polyvinyl alcohol. The pressure in the gap 800 is at least about 400 pli.

Prior to dry-creping the web with a scraper blade 1000, the web consistency is increased to between about 90% and 100%. The scraper blade has a bevel angle of about 25 degrees and is positioned relative to the Yankee dryer drum to provide a cutting angle of about 81 degrees. The Yankee dryer drum is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is formed into a roll at a speed of 650 fpm (200 meters per minute).

The web is treated to form two folded sheets of bath tissue paper. Each sheet has a basis weight of about 12.8 pounds per 3000 square feet and contains about 0.02% temporary wet strength resin and about 0.01% jamming agent binding.

The resulting two-ply tissue paper is soft, absorbent and suitable for use as a paper towel. Each sheet has the following properties:

base weight: 12.8 lb / 3000 sq ft. Macro thickness: 11.4 mi 1 (0.185 mm) bulk density: 0.07 g / cm ^J surface smoothness 22: 850 surface smoothness 24: 100 6 smoothness ratio: 1.18

g / m ² )

Example 3

This example provides two-ply tissue paper, each sheet having 3 layers and each sheet being made on paper

machines of the type shown in Figures 8A, 8B and 8A to 9C.

A 3% by weight NSK (Northern Softwood Kraft) aqueous fiber slurry is manufactured using a conventional pulper. A 2% temporary wet strength resin solution (e.g., National Starch 78-0080, sold by National Starch and Chemical Corporation of New York, New York, USA) is added to the NSK (Northern Softwood Kraft) in the feed tube at a rate of 0 2% by weight on dry fibers. The NSK (Northern Softwood Kraft) slurry is diluted to a consistency of about 0.2% at the centrifugal pump. A second 3% by weight aqueous paper slurry of eucalyptus fibers is prepared using a conventional fiberizing machine. A 2% interfering agent binding solution (e.g., ADOGEN® 442, sold by Witco Corporation of Dublin, OH, USA) is added to one of the eucalyptus slurry feed tubes at a rate of 0.1% by weight based on dry fibers. The eucalyptus slurry is diluted to about 0.2% consistency with a centrifugal pump.

The three individually treated streams for the individual layers (stream 1 = 100% NSK (Northern Softwood Kraft); stream 2 = 100% eucalyptus covered with binding agent; stream 3 = 100% eucalyptus) are kept separate in the headbox and stored on a Fourdrinier a screen to form a three-layer embryonic web comprising an outer eucalyptus layer, a separate eucalyptus layer, and a NSK (Northern Softwood Kraft) layer. Drainage occurs on a Fourdrinier screen and is assisted by a deflector and vacuum cabinets. The Fourdrinier screen has a 5-shed satin woven configuration and has 110 monofilaments per machine direction and 95 monofilaments per machine direction per inch.

9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 999 999

9 ····· · ·

99999 · 9 9 99 99

The embryonic wet web is transferred from a Fourdrinier screen at a fiber consistency of about 8% at the transfer point to the web support apparatus 200 having a dewatering felt layer 220 and a photosensitive resin layer 250 for patterning the web.

Drainage felt 220 is an Amflex 2 Press Felt product manufactured by Appleton Mills, Appleton, Wisconsin, USA. The felt 220 comprises a web of polyester fibers. The web has a denier of surface 3, a substrate denier of 10-15. The felt layer 220 has a basis weight of 1436 g / m 2, a thickness of about 3 mm, and an air permeability of about 30 to about 40 scfm (9.1 to 12.2 Nm ³ / m ² ).

The web patterning layer 250 includes a web contacting the continuous web 260 having a projecting region of about 30 to about 40 percent of the projecting region of the web support apparatus 200. The difference between the elevation 261 of the surface 260 and the elevation 231 of the felt surface 230 is about 0.005 inches.

The embryonic web is transferred to the apparatus 200 to obtain a web 545 supported on the apparatus 200 and having a macroscopically monoplanar, substantially smooth surface 549. Transmission is provided at a vacuum transfer location with a pressure difference of about 20 inches (50.8 mm) of mercury.

Further drainage is provided by vacuum-assisted drainage, such as apparatus 620, until the web has a fiber consistency of about 25%. The belt 545 is then carried next to the steam hood 2880 and to the gap 800 formed between the vacuum pressure roller 900 and the Yankee 880 drying drum.

The surface 26 is pressed into the surface 547 of the belt 545 in the gap 800 by compressing the belt 545 and the belt support apparatus 200 between the vacuum pressure roller 900 and the Yankee 880 drying drum at a gap pressure of about 400 pli (71.4 kg / linear cm). Creping glue up

used to glue the belt to the drying drum Yankee. Prior to creping the web with a scraper blade, the fiber consistency is increased to at least about 90%. The scraper blade has a bevel angle of about 25 degrees and is positioned relative to the Yankee dryer drum to provide a cutting angle of about 81 degrees. The Yankee dryer drum is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is formed into rolls at a speed of 650 fpm (198 m / min).

The strip is transformed into a double-sheet bathroom facial tissue paper, each sheet having three layers. Two-piece toilet tissue comprises about 1.0% temporary wet strength resin and about 0.1% jamming bond.

Each sheet has the following properties;

Base weight: 9.8 lb / 3000 sq ft. (15.9 g / m ² ) macro thickness: 6 mil (0.15 mm) bulk density: 0.10 g / cm ^J surface smoothness 22: 740 surface smoothness 24: 960 smoothness ratio: 1.30

Example 4

This example provides a tissue paper web produced on a paper machine of the type shown in Figures 8Ά, 8B and 9A through 9C.

A 3% by weight NSK (Northern Softwood Kraft) aqueous slurry is prepared in a conventional pulper. A 2% temporary wet strength resin solution (PAŘEZ® 750) is added to the NSK feed tube at a rate of 0.2% by weight of dry fibers. The NSK slurry is diluted to a consistency of about 0.2% n of the circulation pump. Second, they are prepared by weight

3% aqueous conventional fibers are (ADOGEN®442 Eucalyptus consistency of eucalyptus fiber slurry using a pulper. 2% interfering agent binding solution is added to the eucalyptus dosing tube at a rate of 0.1% by weight of dry fibers; about 0.2%.

The two individually treated streams per layer (stream 1 = 100% NSK, stream 2 = 100% eucalyptus) are mixed in a headbox and deposited on a Fourdrinier screen to form a single layer of NSK fiber and covered with eucalyptus fibers, the eucalyptus fibers being covered with binding agent. Drainage takes place through a Fourdrinier screen and is assisted by a deflector and vacuum cabinets. Fourdrinierovo

the screen has a 5-shed satin fabric configuration having 110 monofilament fibers direction across the machine. per inch in direction along the machine and 95 ve Embryonic wet belt Yippee transmitted of Fourdrinier sieves at fiber consistency about 8% at the transition point to passport

supporting 200 having a dewatering felt layer 220 and a photosensitive resin web patterning the layer 250.

The dewatering felt 220 is of Amflex 2 Press Felt manufactured by Appleton Mills of Appleton, Wisconsin, USA. The web pattern 250 comprises a continuous web contacting surface 60. The web pattern 25 has a projecting area equal to about 35 percent of the raised surface of the web support apparatus 200. The height difference between the upper web contacting surface 260 and the first felt surface 230 is about 0.005 inches. 0.127 mm).

The embryonic web is transferred to the web supporting apparatus 200 and is bent in the first bending stage to form generally ·· 99 • 0 0 0 0 0

0 0 · 0 0 • 0 · 900 009 • · 4 0

40 49 • · 00 00 monoplanar belt 545. The transfer is performed at a vacuum transfer point by a pressure difference of about 20 inches of mercury. Further dewatering is achieved by vacuum-assisted dewatering until the web has a fiber consistency of about 25%. The belt 545 is supported by a belt supporting apparatus which, in addition to the steam hood 2800 and within a gap 800 formed between the vacuum pressure roller 900 and the Yankee 880 drying drum, the belt 545 is then compacted against a compacting surface 875 of the Yankee 880 drying drum at a pressure of at least about 400 pli. , 4 kg / linear cm). A polyvinyl alcohol-based creping adhesive is used to adhere the compacted web to the Yankee drying drum. Prior to dry-creping the web with the surface of the drying drum 880 with a scraper knife, the fiber consistency is increased to at least about 90%. The scraper blade has a bevel angle of about 25 degrees and is positioned relative to the Yankee dryer drum to provide a cutting angle of about 81 degrees. The Yankee dryer drum is operated at about 800 fpm (feet per minute) (about 244 meters per minute). The dry web is formed into a roll at a speed of 650 fpm (200 meters per minute).

The web is converted into a single layer two-ply paper towel, each sheet of two-ply bath tissue having a basis weight of about 12.6 pounds per 3000 square feet and containing about 0.2% by weight temporary wet strength resin and about 0.1% by weight of the jamming bond. reagents.

The resulting two-ply tissue paper is soft, absorbent and suitable for use as a paper towel.

Tissue paper has the following characteristics:

Base weight: 12.6 lb / 3000 sq ft. (20.5 g / m ² ) macro thickness: 8.8 mil (0.22 mra) bulk density: 0.092 g / cm ³ surface smoothness 22: 890 surface smoothness 24: 1050 • ··· φ φ φ · φφφ φ φφφ φ φ poměr poměr hlad hlad hlad poměr poměr hlad poměr poměr

Hypothetical example:

The following hypothetical example illustrates a method of making a two-ply tissue paper using a commercial size paper machine of the type shown in Figures 8A, 8B and 9A to 9C.

A 3% by weight NSK (Northern Softwood Kraft) aqueous slurry is prepared in a conventional pulper. A 2% temporary wet strength resin solution (PAŘEZ® 750 manufactured by American Cyanamid Corporation of Stanford, CT) is added to the NSK feed tube at a rate of 0.2% by weight of dry fibers. The NSK slurry is diluted to a consistency of about 0.2% at the circulation pump. Second, a 3% by weight aqueous paper slurry of eucalyptus fibers is prepared using a conventional pulper. A 2% interfering agent binding solution (ADOGEN® 442, manufactured by Witco Corporation of Dublin, OH, USA) is added to the eucalyptus fiber feed tube at a rate of 0.1 weight dry fibers.

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They are mixed in a headbox and are screened to form monolayer streams on individual layers, deposited on a Fourdrinier web of NSK fibers and coated with eucalyptus fibers, wherein the eucalyptus fibers are coated with a interfering agent. Drainage takes place through a Fourdrinier sieve and is it assisted by an effector? and vacuum cabinets. The fouxurin dioxide mesh has a 5-shed satin fabric configuration having 110

- 47 · ofil »· • · · monφφ monφφφofilofilofilofilofilofil mon monofil monofil mon monofilofil mon mon mon mon mon mon mon mon mon mon mon monofil mon monofil mon mon monofil mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon mon 4 / cm).

The embryonic wet web is transferred from a Fourdrinier sieve at a fiber consistency of about 10% at the transition point to the web supporting apparatus 200 having a dewatering felt layer 220 and a photosensitive resin web patterning the layer 250.

The dewatering felt 220 is of Amflex 2 Press Felt manufactured by Appleton Mills, Appleton, Wisconsin, USA. The web patterning layer 250 includes a continuous web patterning layer. koU f majLui. ctox vg> v ± π <dtci.d ± i ou ± ua.vc uillxo tciiyoii / o 2 oval shaped, holes 270 per square inch (10.7 / cm) strip of contact surface 220. The strip patterning layer 250 has a protruding surface flat about 35 percent of the protruding surface of the web supporting apparatus 200. The height difference between the upper web communicating surface 260 s. The felt surface 230 is about 0.005 inch (0.127 mm).

The embryonic waist is transmitted κ to the zun apparatus supporting a generally monoplanar strip 545. The transfer is performed at a vacuum transfer point by a pressure difference of about 20 inches (508 mm) of mercury column. Further dewatering is achieved by vacuum-assisted dewatering until the web has a fiber consistency of about 30%.

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Vacuum pressure roller 900 has a pressure surface 910 having 545 is then compacted compared to a Yankee hardness as well as about compacting.

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880 by pressing the waist 545 and the waistband of the apparatus between

1 i 1 a Q Q Q Q Q Q 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 A polyvinyl alcohol-based creping adhesive is used to adhere the compacted web to the Yankee drying drum. Before creping the Z 3 dryness with the surface of the drying drum 880 with a scraper knife • tttt tttt the fiber consistency increases to at least about 90%. The scraper blade has a bevel angle of about 20 degrees and is positioned relative to the Yankee dryer drum to provide a cutting angle of about 76 degrees. The Yankee dryer drum is operated at about 4500 fpm (feet per minute) (about 1372 meters per minute). The dry web is formed into a roll at a speed of 3690 fpm (1125 meters per minute).

The belt is transferred to a two-sheet paper towel. Each sheet of two-ply bath tissue has a basis weight of about 12.5 pounds per 3,000 square feet (278.7 m ² ) and contains about 0.2% by weight temporary wet strength resin and about 0.1 % by weight of the interfering agent binding.

The resulting two-ply tissue paper is soft, absorbent and suitable for use as a paper towel.

Analytical procedures

Paper thickness and height measurements:

Placement of the plane 23 of the regions 30, the thickness of the region 30, and the thickness of the region 50 are determined using micrographs of the transverse micro-sections of the paper web. An example of such a photomicrograph is shown in Figure 3 where the placement of the plane 23 together with the thickness P of the region 50 and the thickness K of the region 30 is shown.

Ten samples, each measuring about 2.54 x 5.1 cm (1 inch x 2 inches), are randomly selected from a sheet or roll of tissue paper. If ten samples cannot be obtained from a single sheet, then additional sheets produced under the same conditions (preferably from the same original roll) may be used.

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Micro-cuts of the same sample are made by stacking each sample on a rigid cardboard holder. The cardboard holder is placed in a silicone mold. The paper sample is immersed in a resin such as Merigraph photopolymer, manufactured by Hercules, Inc.

The sample is cured to cure the resin direction. The sample is removed from the silicone mold. Prior to insertion into the photopolymer, the sample is marked with a reference point to determine exactly where the micro-cuts were made.

Preferably, the same reference point is used for both the plan view (ie, Figure 4) and the different cross-sections (ie, Figure 3) of the belt sample 20.

The sample is placed in a 860 micro-cut manufactured by the American Optical Company, Buffalo, New York, USA, and aligned. The edge of the sample is removed from the sample in the slices by a micro-cut until a smooth surface appears.

A sufficient number of micro cuts are removed from the sample to accurately reconstruct the various areas of the paper web (i.e., 30 and 50). For the embodiment described herein, slices having a thickness of about 60 microns per slice are removed from the smooth surface. Multiple slices may be required to determine the thickness P and K.

The sample slice is mounted on a microscope slide using oil and a cover slip. The slide and sample are mounted on a ray microscope and observed at 40X magnification. Micrographs are taken along the wafer and the individual micrographs are arranged in series to reconstruct the sectional profile. Thicknesses and heights can be determined from the reconstructed profile as shown in Figure 3, which is a cross section micrograph of the paper structure of the type shown in Figures 1 and 2.

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The thicknesses are determined using the Hewlett Packard ScanJet IIC flatbed color scanner, which scans micrographs and saves them as a graphic file on a personal computer. The scanning software from Hewlett Packard is DeskScan II version 1.6. The scanner is set to scan black and white photos. The path is Laser Writer NT, NTX. The brightness and contrast settings are 125. The scale is 100%. The file is scanned and saved as an image file on a Macintosh IlCi. The image file is opened with a suitable image software package or CAD program, such as PowerDraw version 6.0, available from Engineering Software, North Carolina, USA.

With reference to Figure 3, the thicknesses of the regions 30 and 50 are indicated by rings having their diameters designated K and K respectively. P. First, draw the largest circle that can be inscribed in the area 50 under investigation using PowerDraw software. The diameter of this ring is designated P. The thickness P of the region 50 is the diameter of this ring multiplied by the respective magnification coefficients. (The magnification factor is the magnification of the micrograph multiplied by the magnification of the scanned image).

Next, the smallest rings that can be inscribed in portions of region 30 on both sides of region 50 are drawn. The diameters of these rings are designated K. The thickness K of region 30 next to region 50 is the diameter of the two diameters multiplied by the above scale factor.

The plane of the region 30 adjacent to the region 50 is located by drawing a line connecting the centers of the two rings having a diameter K as shown in Figure 3.

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For each of the ten samples, each occurrence of the relatively thicker region 50 is drawn a line representing plane 23. If this line intersects the region 50 in at least 25 percent occurrences, then the paper from which the samples were taken has relatively thicker regions located in the plane of the relatively thicker region. . For example, if ten samples give 50 occurrences of a relatively thicker region 30 on each side of a relatively thicker region 50, then the relatively thicker regions 50 are considered to be located in the plane of the relatively thinner region 30 if and only if the drawn line representing plane 23 intersects the thicker region 50 at least 13. of 50 occurrences.

Surface smoothness:

The surface smoothness of the paper web side is measured according to the physiologic surface smoothness (PSS) method established at the 1991 International Paper Physics Conference, TAPPI, in an article from page 19 of Book I entitled "Methods for measuring the mechanical properties of tissue paper." by Ampulski et al., the disclosure of which is hereby incorporated by reference. The PSS measurement as used herein is a point-to-point sum of amplitude values as described in the above article. The measurement procedures set forth in the article are also generally described in U.S. Patent 4,959,125 issued to Spendel and U.S. Patent 5,059,282 issued to Ampulski et al., The disclosures of which are incorporated herein by reference.

For the purposes of testing the paper samples of the present invention, the PSS measurement method in the above article is used to measure surface smoothness with the following process modifications:

Instead of importing pairs of digitized data (amplitude and time) into the SAS software for 10 samples, as described in • ··· 0 · · ···

400 00

0000 • 0

0 4 • 00 0 0 0 • 0 0

00 0 0 0 0 0 0 0 0

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00 of the above sample, surface smoothness measurement is performed by acquiring, digitizing and statistically processing data for 10 samples using the LABVIEW software available from National Instruments, Austin, Texas, USA. Each amplitude spectrum is generated using the Amplitude and Phase Spectrum.vi module in the LABVIEW software package, with Amp Spectrum mag Vrms selected as the output spectrum. The output spectrum is obtained for each of the 10 samples.

Each output spectrum is then smoothed using the following LABVIEW weight coefficients: 0.000246, 0.000485, 0.00756, 0.062997. These weighting coefficients are selected to imitate the smoothing provided by the 0.0039, 0.0077, 0.120, 1.0 coefficients specified in the above article for the SAS program.

After smoothing, each spectrum is filtered using the frequency filters specified in the above article. The PSS value in microns is then calculated as described in the above-mentioned article for each individually filtered spectrum. The smoothness of the surface of the paper web side is the average of 10 PSS values measured from 10 samples taken from the same side of the paper web. Similarly, the smoothness of the surface of the opposite side of the paper web can be measured. The smoothness ratio is obtained by dividing the higher surface smoothness value corresponding to the more textured side of the paper web by the lower surface smoothness value corresponding to the smoother side of the paper web.

Base weight:

The basis weight is measured according to the following procedure:

The paper to be measured is treated for a minimum of 2 hours at 71-75 degrees Fahrenheit (21.7 to 23.9 ° C) to a relative temperature of 111 1.

111 11

112 11 11

11 1 1111 1 1111 1 1 111 111 1 11 1 11 11 humidity 48 to 52 percent. The treated paper is cut to give twelve samples measuring 3.5 inches by 3.5 inches (8.9 x 8.9 cm). The samples are cut, six samples at a time, with a suitable pressure die cutter, such as a Hydraulic Pressure Sample Cutter, type 240-10 from Thwing-Albert Alfa. The two stacks of six samples are then combined into 12 sheets containing the stack and conditioned for at least 15 additional minutes at 71-75 F (21.7-23.9 ° C) and 48-52 percent humidity.

The 12-sheet stack is then weighed on a calibrated analytical balance. The scales are kept in the same room where the samples were treated. Suitable scales are manufactured by Sartorius Instrument Company as type A200S. The weight thus obtained is the weight in grams for a 12-sheet stack of paper, each sheet having an area of 12.25 square inches (79 cm ² ).

The basis weight of the paper web (weight per unit area per sheet) is calculated in pounds per 3000 square feet using the following equation:

weight of 12-sheet stack (grams x 3000 x 144 th inches per foot (453.6 g / lb) x (12 sheets) x (12.25 sq. in. per sheet) or simply: basis weight (lb / 3000 ft ² ) = stack weight 12 sheets (g) x 6.48

Macro thickness or dry thickness dimension

The macro thickness or dry thickness dimension is measured using the dry thickness measurement method described in U.S. Patent 4,469,735, issued September 4, 1984 to Trokhan, which patent is hereby incorporated by reference.

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9

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9 9

99 99 ··. 9 9 9

998 9 9

9

9

999 99 99

9999

99

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Bulk density

The bulk density is the basis weight of the web divided by the macro thickness of the web.

Absorption capacity

The absorbency of the strip is measured using the horizontal absorbency test described in U.S. Pat. No. 4,469,735.

Measuring the heights of the belt supporting apparatus

The height difference between the height 231 of the first felt surface and the height 261 of the strip of contacting surface 260 is measured using the following procedure. The belt supporting the apparatus is supported on a flat horizontal surface with the belt patterning layer facing upwards. A stylus having a circular contact surface of about 1.3 mm and a vertical length of about 3 mm is mounted on a thickness gauge from Federal Products Company (Amplifier Type 432B-81 modified for use with the EMD4320 WI tear-off sensor), Providence, Rhode Island, USA. The instrument is calibrated by determining the voltage difference between two precision inserts of known thickness that provide a known height difference. The device is zeroed at a height slightly lower than the first felt surface 230 to ensure unrestricted operation of the stylus. The stylus is positioned above the appropriate height and lowered to perform the measurement. The stylus produces a pressure of about 0.24 g / mm at the measuring point. At least three measurements shall be taken at each altitude. The measurement of each height is averaged. The difference between the average values is calculated, which gives the difference in heights.

The same procedure is used to measure the difference between heights 1231 and 261 as shown in Figure 14B.

Claims (7)

PATENT CLAIMS A wet-laid paper web having first and second oppositely facing surfaces having a relatively thinner, continuous network region and a plurality of relatively thicker discrete regions dispersed in the continuous network region, wherein the relatively thicker discrete regions are disposed in a continuous plane. network area. 2. The paper web of claim 1 having a basis weight in the range of about 7 to about 70 g / m @ ² . The third paper web according to claim 1 or 2, characterized in that the paper web has a macro caliper of at least about 0.1 mm and a bulk density less than about 0.12 g / ^cc. Paper web according to claim 1, 2 or 3, characterized in that both the continuous network and discrete areas are shortened beforehand. The paper web of claim 1, 2, 3, or 4, wherein the surface smoothness ratio of the web is greater than about 1.15, preferably greater than 1.20, and most preferably greater than 1.25. The paper web of claim 1, 2, 3, 4 or 5, wherein the second surface of the web has a surface smoothness value of less than about 900. The paper web of claim 1, 2, 3, 4, 5, or 6, wherein each discrete relatively thicker region surrounds at least one discrete densified region.