KR20000016661A - Chemically enhanced multi-density paper structure and method for making same - Google Patents

Abstract

PURPOSE: A paper structure is provided to add a functional chemical in accordance with a micro-area for improving a flexibility and a tensile strength while not effecting a harmful influence to the flexibility. CONSTITUTION: A chemically enhanced paper structure (20) having a discrete pattern of a chemical composition is disclosed. The paper structure (20) comprises a cellulose substrate (22) such as tissue paper. The substrate has regions of relatively high (34) and relatively low (38) densities. The chemical composition (24) may include a chemical softener composition or a surface-active composition and is preferentially applied to the low density regions (38) of the substrate. Preferably, the low density regions (38) are discrete (36), so that an essentially continuous high density network (32) is present between the low density regions (36, 38). The paper structure is suitable for use as bath tissue or facial tissue. Preferably, the additive (24) is applied to the paper (22) from a solution (40) in an apparatus (50) comprising at least two axially rotatable rolls, i.e. an anvil roll (56) and optionally a transfer roll (54) and a metering gravure roll (52), forming a gap (60) through which the paper (22) passes, and optionally a nip (58).

Description

Paper structure having a multi-density region with improved physical properties by chemicals and a method of manufacturing the same

Consumer goods such as toilet tissues, towels and cosmetic tissues made from cellulosic webs are a big part of the modern world. In general, these products need to have some important physical properties that are considered acceptable to consumers. The exact mixing of the important properties and the absolute value of the individual properties vary depending on the product's properties, but flexibility and wetting and dry stiffness, absorbency and appealing aesthetic properties are, among other things, desirable properties. Flexibility is a property of the fibrous web that produces a pleasant tactile response and when the product contacts human skin or other fragile surfaces, the product is not at all rough or abrasive. Stiffness is the ability of a structure to retain its physical integrity in use. Absorbency is a property of fibrous structures that can trap and contain fluids in contact at the appropriate time. Aesthetic properties refer to the psycho-visual response that occurs when a consumer looks at the product in its package or alone.

A common method of making tissue products is a wet laid papermaking process. In this process, the individual fibers are first suspended in dilute slurry with water. This slurry is then placed on a porous screen to remove most of the water to form a thin, relatively uniform weight of the initial web. This initial web is then molded and / or dried in a number of ways to produce the final tissue web. As part of this process, the molded / molded or dried web is typically bonded to the drying drum and continuously creped from the surface of the dryer to impart the desired properties.

Products produced by many existing wet lamination processes fall within the foregoing. Examples of webs that are soft, tough, absorbent and contain densities of two or more microregions are described in US Pat. No. 3,301,746 to Lawrence H. Sanford and James B. Sisson, issued January 31, 1967; U.S. Patent No. 3,974,025 to Peter G. Ayers, August 10, 1976; US Patent No. 3,994,771 to George Morgan, Jr. and Thomas F. Rich, issued November 30, 1976; US Pat. No. 4,191,609 to Paul D. Trokhan, issued March 4, 1980, and US Pat. No. 4,637,859, issued to Paul, January 20, 1987. Each of these papers is characterized by a repeating pattern of dense and less dense areas. Such dense regions may be discontinuous or continuous. These dense areas are created from localized compression of the web during the papermaking process by the raised areas of the imprinting carrier fabric or belt.

Other very bulky and soft tissue papers are disclosed in US Patent No. 4,300,981 issued to Jerry E. Carstens on November 17, 1981; And US Patent No. 4,440,597, issued April 3, 1984 to Edward R. Wells and Thomas A. Hensler.

Paper structures having improved physical properties by chemicals, including cellulose substrates and having enhanced properties by chemicals, are known in the art. For example, a method for producing bulky and soft absorbent tissue paper by using a peptizer and an elastomeric binder together in paper furnishings to avoid overall compression is described by JLSalvucci, Jr., May 21, 1974. US Pat. No. 3,812,000.

US Pat. No. 3,755,220, issued to Frimark et al. On August 28, 1973, as chemical peptising agents and their theory of operation as expected by Salbutch, cited above; US Patent No. 3,844,880 to Meisel et al. On October 29, 1974; And US Pat. No. 4,158,594, issued to Becker et al. On January 19, 1979.

Tissue paper has also been improved with flexibility by treating with cationic surfactants as well as noncationic surfactants. For example, US Pat. No. 4,959,125 to Spendel, Sep. 25, 1990; And US Pat. No. 4,940,513, issued to Spendel on July 10, 1990, discloses a method for enhancing its flexibility by treating tissue paper with a noncationic, preferably nonionic surfactant.

It has been found that the flexibility of tissue papers, especially dense tissue papers in very bulky patterns, can be improved by treating them with various formulations (eg, vegetable, animal or synthetic oils, and in particular polysiloxane materials generally referred to as silicone oils). It was. See, for example, US Pat. No. 5,059,282, issued to Ampulski et al. On October 22, 1991. The Ampulsky patent discloses a method for adding a polysiloxane compound to a wet tissue web (preferably at a fiber consistency of about 20 to about 35%). These polysiloxane compounds give the tissue paper a shiny soft feel.

Although the process described above produces acceptable product properties, the product properties can be further improved. However, the process of making conventional and potentially improved products has some disadvantages. For example, chemicals used to reinforce tissue webs are often added to a thin slurry of water and fibers before they are initially placed on a forming screen. This is a relatively convenient and inexpensive method for introducing additives. However, other chemicals to aid in absorbency or to improve flexibility are also typically added at the end of the wetting of the so-called tissue making process. Because of the complex nature of the individual chemicals used to generate important properties, these drugs often interact with each other in a negative way. Not only can they compete with each other for the desired retention on cellulose fibers, but they can also destroy the inherent properties of the fibers. For example, flexible chemicals often reduce the inherent tendency of the fibers to bond with other fibers and thus reduce the functional stiffness of the resulting web. The introduction of chemical papermaking additives at the end of the wetting keeps both process and product advantages to a minimum.

If the chemicals are to be functional, the additives introduced at the end of the wetting of the process must be retained by the cellulose fibers. This is usually done by using a chemical with an ionic charge, most preferably a positive ion charge attracted to the intrinsic anionic charge of cellulose. Many additives that can improve the properties of the web are not charged. The introduction of these chemicals into thin fiber slurries at the end of the process wetness results in poor retention and further exacerbates the interference problem described above.

The process for adding rigid and flexible additives at the end of the wetting process of papermaking is described in US Pat. No. 5,223,096 to Phan and Trocan on June 29, 1993, and to June 8, 1993. US Pat. No. 5,217,576. These late wetting processes generally add uniformly rigid and flexible additives to the tissue paper and therefore will not prevent any undesirable potential interaction of the chemical.

Another disadvantage of adding any chemical at the end of the process's wetting is that it is dispensed through the web if the chemical is retained. In many cases, it is desirable to apply the active ingredient only to the surface of the web. This may be desirable, for example, for smooth flexible materials. If the material is applied only to the surface, it can be used efficiently because consumers only interact with the surface tactilely. Application to the surface also avoids interference with other materials, for example, rigid additives best contained in the center of the sheet.

Chemical papermaking additives may also be added to the cellulose substrate following the formation of the wet web. For example, chemical additives can be applied to a cellulose substrate from an aqueous chemical solution and then dried to form a paper structure with improved chemical properties. Unfortunately, the prior method of adding a chemical to the cellulose substrate allows for uniform or homogeneous distribution of the chemical on the substrate. Such homogeneous or homogeneous distribution of chemicals may negate many of the performance advantages offered by cellulose substrates containing densities of two or more microregions.

The present invention overcomes all of the above mentioned disadvantages and generates desirable additional advantages. In particular, the addition of functional chemicals to precisely match the micro-area of the cellulose substrate allows the present invention to maximize the performance advantages of multi-area paper. For example, as detailed below, chemically flexible additives are added to the low density micro region of the web to further enhance its action.

Generally, the chemical composition is applied to the cellulose substrate by spraying or printing. Unfortunately, it is difficult to spray the chemical composition onto the substrate in the correct pattern. Printing the chemical composition onto a substrate can form a more limited and accurate pattern than can be obtained by spraying, but a printing roll with raised bumps or gravure cells is required. The printing rolls and gravure plates with raised projections define the pattern of the applied chemical composition to the pattern corresponding to the projections of the printing roll or gravure plate, regardless of which pattern is particularly desirable for the capillary substrate. In addition, it is very difficult to accurately fit the printed pattern into the micro area of the substrate.

This problem can be overcome by providing an excess of one of each desired pattern of printing roll and gravure plate. However, this provision increases the cost of the device to the extent economically possible to provide a printing roll or gravure plate for each desired pattern, as long as a short production run is desired.

Therefore, certain micro-areas of tissue paper, especially bulky pattern dense tissue paper,

(1) can be performed with commercially available papermaking systems without significantly affecting machine workability;

(2) use chemical compositions that are nontoxic and environmentally desirable;

(3) can be carried out in a manner that can maintain the desired tensile stiffness, absorbency and low lintability of the tissue paper;

It is preferable to be able to improve chemically by the method.

Importantly, by adding functional chemicals to the desired micro-regions in accordance with the teachings of the present invention, the desired functional properties can be improved without adversely affecting other properties. For example, increase tensile stiffness without adversely affecting flexibility; Alternatively, flexibility can be improved without adversely affecting tensile stiffness.

It is an object of the present invention to provide a soft absorbent toilet tissue paper product.

It is an object of the present invention to provide a soft absorbent cosmetic tissue paper product.

It is an object of the present invention to provide a soft absorbent paper towel product.

It is an object of the present invention to provide a paper structure, for example a tissue web, comprising a cellulose substrate containing a density of at least two micro areas, wherein the chemical papermaking additive is introduced to exactly fit into the micro areas of the paper structure.

It is yet another object of the present invention to provide an improved method for introducing into a tissue web with improved flexibility, chemical removal additives, stiffness, absorbency and aesthetics or a combination thereof.

It is another object of the present invention to provide an improved method for introducing chemical papermaking additives that is precisely aligned with the micro-area of the tissue web in order to maximize the performance advantages of multi-area paper.

These and other objects are obtained using the present invention, which can be seen from the following more detail.

Summary of the Invention

The present invention is a paper structure having improved physical properties by a chemical including a cellulose substrate having a relatively high density first region and a relatively low density second region. The areas of relatively high density and areas of relatively low density are each arranged in a non-irregular repeating pattern. Immobilized chemical papermaking additives are disposed on areas of relatively high density or areas of relatively low density.

In a particularly preferred embodiment, the areas of relatively high density essentially form a continuous network and the areas of relatively low density are discontinuous. In this embodiment, the immobilized chemical papermaking additive is preferably disposed on a low density region, for example if it is intended to improve flexibility and / or absorbency. In addition, immobilized chemical papermaking additives can be added to continuous high density regions, for example, to improve rigidity. In addition, as will be discussed in detail later, paper structures having improved physical properties by the chemicals of the present invention are preferably through-air dry.

Although the present invention concludes with the claims that specifically point to and specifically characterize the invention, the invention will be better understood with reference to the following detailed description taken in conjunction with the accompanying drawings.

The present invention relates to a paper structure having improved physical properties by a chemical including a cellulose substrate and a chemical papermaking additive. More specifically, the present invention relates to a paper structure comprising a cellulose substrate containing at least two micro-area densities or basis weights, wherein the chemical papermaking additive is introduced exactly in the micro-area of the paper structure.

1 is a fragmentary top view of a paper structure according to the present invention with discontinuous sites of continuous cellulose network and chemical papermaking additives.

2 is a fragmentary side elevational view taken along line 2-2 of FIG.

3 is a schematic vertical elevation view of one device that can be used to make the structure of the present invention.

As illustrated in FIG. 1, the paper structure 20 with improved chemical properties in accordance with the present invention generally comprises a planar cellulose substrate 22 and a chemical papermaking additive 24. The chemical papermaking additive 24 is generally applied to the cellulose substrate 22 in the form of the aqueous solution 40 shown in FIG. 3. In FIG. 3, an aqueous solution 40 is applied to the cellulose substrate 22 in a specific pattern. Once the aqueous solution 40 is placed on the cellulose substrate 22, the water is finally removed by drying, leaving the chemical papermaking additive 24 on the cellulose substrate.

Returning to FIG. 1, the cellulose substrate 22 is a cellulose structure, preferably a tissue paper web. The cellulose substrate 22 includes a plurality of micro-regions 34 and 38 having different basis weights and / or densities. Regions 34 and 38 of any arrangement of cellulose substrate 22 are acceptable as long as cellulose substrate 22 is macroplanar and chemical papermaking additive 24 is immobilized to fit exactly one of the micro-regions.

The cellulose substrate 22 according to the invention has distinguishable micro-regions 34 and 38 which define two mutually different densities. Preferably, region 34 and region 38 are arranged in an arrangement comprising essentially continuous network region 32 and discontinuous region 36, essentially within a continuous network. As used herein, the region 32 extending substantially completely through the cellulose substrate 22 in one or both of the principal dimensions is considered as “essentially continuous network”. Conversely, non-adjacent region 36 is considered "discontinuous". This discontinuous region 36 extends outward from the region 32, which essentially defines a continuous network, to the distal end.

Preferably, discontinuous region 36 and essentially continuous network region 32 are arranged in a non-irregular repeating pattern. The expression “non-irregular” herein may occur as a result of known and predetermined features of the fabrication process, where regions 32 and 36 are considered to be predictable. The term "repeated" means that the pattern is formed one or more times in the cellulose substrate 22. However, as the consumers know, if the cellulose substrate 22 is relatively small and the pattern is relatively large or the paper structure 20 is known to the consumer as a unitary unit, this pattern only occurs once in the cellulose substrate 22. Can be. More preferably, region 34 and region 38 of cellulose substrate 22 are essentially continuous network region 32, and discontinuous low density region 36 is essentially continuous network region 32. Are arranged in an array. Preferably, the discontinuous low density region 36 and essentially continuous network region 32 will occupy different locations, as discussed later.

For the embodiments discussed herein, the cellulose substrate 22 (per square inch) having about 2 to about 155 low density discontinuous regions 36 (preferably with a chemical papermaking additive 24 disposed thereon) per cm 2. 10 to 1000 discrete areas 36) and more specifically about 16 to about 109 low density discrete areas 36 (100 to 700 discrete areas 36 per square inch) have been found to be suitable. .

In addition, the cellulose substrate 22 according to the invention may comprise two different ridges 26. The “ridges” of the cellulose substrate 22 are portions that are partially out of planarity. The ridge 26 of the substrate is flattened and measured using the horizontal plane as the comparison plane. The different ridges 26 of the cellulose substrate 22, which may or may not coincide with the regions 34 and 38 of the different densities described above, take the comparison plane and the principal dimensions of the cellulose substrate 22 vertically and the comparison plane. Determined by the difference from the raised height.

Preferably, the regions 34 and 38 defined by the different densities and the different ridges 26 coincide. Thus, the discontinuous low density region 36 is also raised at the ridge 26 from the high density region 34 of the essentially continuous network region 32 at the ridge 26 (or the cellulose substrate 22 is When flipped, it descends from the ridge 26). However, it should be understood that there may be suitable embodiments where the discrete areas 36 of a particular density do not coincide with a particular ridge 26.

The cellulose substrate 22 according to the invention can be composed of cellulose fibers (along the longitudinal axis of the fiber) with one very large dimension compared to the other two relatively small dimensions (radial and Perpendicular to each other), linearity is estimated. Microscopic examination of the fibers shows that the other two dimensions are small compared to the principle dimensions of the fibers, and these other two small dimensions need not be substantially identical or constant throughout the axial length of the fibers. It is important only if the fibers can be bent around an axis, bent against other fibers and can be distributed onto the forming wire (or equivalent thereof) by the liquid carrier.

The cellulose substrate 22 may or may not be creped as desired. Creping the cellulose substrate 22 may shorten the Z-direction wave through the essentially continuous network region 32. This undulation produces transverse machine folds, which are considered to be too small in comparison to the differences in ridges 26 obtainable by the methods discussed below, so that there is little difference from ridges 26. However, it should be understood that the creped cellulose substrate 22 may be embossed, such as through aeration drying, to create a difference in the ridge 26 that is relatively large relative to creping ripples and folds. The method of making the uncreped, aerated dried tissue paper product is described in European Patent Application No. 0 677 612 A2, assigned to Kimberly-Clark Corporation, published October 18, 1995. Which is incorporated herein by reference. Such uncreped and aerated structures are suitable for the practice of the present invention.

The fibers comprising the cellulose substrate 22 are synthetic fibers, ie polyolefins or polyesters and are preferably cellulosic fibers such as cotton linter, rayon or vargas, more preferably wool pulp, eg For example, soft wood (bark or conifer) or hard wood (pizza or hardwood) may be crosslinked and may comprise a combination of synthetic and cellulosic materials. As used herein, cellulose substrate 22 is considered, but not limited to, "cellulosic" if cellulose substrate 22 comprises at least about 50% or at least about 50% by volume of cellular fibers. Wood pulp fibers comprising soft wood fibers having a length of about 2.0 to about 4.5 mm and a diameter of about 25 to about 50 μm, and hard wood fibers having a length of less than about 1 mm and a diameter of about 12 to about 25 μm The cellulosic mixture of was found to fit well with the cellulose substrate 22 described herein.

If wood pulp fibers are selected for the cellulose substrate 22, these fibers may be produced by any pulp process, including chemical processes such as sulfite, sulfate and soda processes and mechanical processes such as stone groundwood. Can be. Optionally, the fibers can be produced or recycled by a combination of chemical and mechanical processes. The type, combination and processing of the fibers used are not critical to the invention.

The cellulose substrate 22 according to the present invention is macroscopically two-dimensional in plan and three-dimensional in some thickness. However, the three-dimensional thickness is small compared to the ability to produce a cellulose substrate 22 having a relatively large measurement in the primary two-dimensional dimension or the primary two-dimensional dimension.

The cellulose substrate 22 according to the present invention comprises a single stack and can be laminated or layered as a fiber type. However, it should be understood that two or more single stacks made in accordance with the present invention may be connected in opposing relationship to form an integral stack.

Of course, it should be understood that woven or nonwoven fabrics may be suitably used as the cellulose substrate 22, provided that the density requirements specified above are met.

Cellulose substrate 22 having regions 34 and 38 of different densities can be suitably either localized through embossing, or as appropriate to a particular region, as is known to those skilled in the art. It can be achieved by densification by vacuum or pressure deflection into a mold and then by air drying as is well known to those skilled in the art. Similarly, the cellulose substrate 22 having different ridges 26 in a direction generally perpendicular to the plane of the cellulose substrate 22 may be achieved by embossing as well known to those skilled in the art. Or by vacuum or pressure deflection into a suitable mold followed by aeration drying as is well known to those skilled in the art.

Preferably, the paper structure improved by the chemical of the present invention is air dried. Particularly preferred aerated dried cellulose substrate 22 is prepared in accordance with commonly assigned US Pat. No. 4,529,480 to Trocan, dated July 16, 1985, which is herein referred to as a discontinuous region 36 and essential. It is hereby incorporated by reference for the purpose of showing a method for producing a particularly preferred cellulose substrate 22 according to the invention with a vented dry cellulose substrate 22 having a continuous pattern region 32 and having different ridges 26. . Cellulose substrates 22 manufactured according to US Pat. No. 4,529,480 to Trocan have discontinuous regions 36 that match each other, which regions 36 have a relatively low density and rise in the ridges 26 ( Or descent).

Cellulose substrate 22 preferably has a difference in ridge 26 between different areas 34 and areas 38 of at least about 0.13 mm (0.005 inches). The ridge 26 is measured without defined pressure using microtomoscopy or stereoscopic three dimensional scanning electron microscopy images as is well known to those skilled in the art.

Chemical papermaking additives 24 may be applied to cellulose substrates in aqueous solutions, emulsions, suspensions and the like. For example, an aqueous solution 40 containing the chemical papermaking additive 24 can be applied to the cellulose substrate 22 as illustrated in FIG. 3.

A specific type of chemical papermaking additive 24 is applied and immobilized in a pattern over which the chemical papermaking additive 24 extends, such that the chemical papermaking additive 24 does not flow, move or be transported to different portions of the cellulose substrate 22. The less useful property of is not critical to the invention unless it changes the desired pattern (eg, uniform coating). The chemical papermaking additive 24 is preferably passivated even in dry and wet conditions during use.

In FIG. 2, an aqueous solution 40 containing a chemical papermaking additive 24 is preferably arranged in a predetermined pattern, in particular fit and immobilized in the discontinuous low density region 38 of the cellulose substrate 22. Although in other patterns, semi-continuous patterns are possible, forming discontinuous low densities that form lines extending through substantially one principle dimension of the cellulose substrate 22 (ie, machine direction, transverse direction, or diagonal thereof). Preferred is a pattern with chemical papermaking additives 24 disposed only in region 38. In this preferred embodiment, the relatively high density region is substantially free of immobilized chemical papermaking additives 24.

In FIG. 3, the paper structure 20 with improved physical properties by the chemical according to the present invention may be manufactured according to the apparatus 50 of FIG. 3. The device 50 of FIG. 3 preferably has three axially rotatable rolls 52, 54 having longitudinal axes parallel to each other, a metering roll 52, a moving roll 54, and an anvil roll 56. , And 56). Three rolls 52, 54, and 56 form a nip 58 and a gap 60. Nip 58 is between metering roll 52 and moving roll 54. The gap 60 is between the moving roll 54 and the anvil roll 56.

The metering roll 52 is a gravure roll disposed in the receiving tank 62 of the liquid precursor 40. During axial rotation, the metering roll 52 captures the liquid precursor 40 from the reservoir 62 and fills in each cell of the metering roll 52 by a doctor blade 41. The water level is correctly adjusted and then a certain amount of the aqueous solution 40 is transferred to the transfer roll 54. The cellulose substrate 22 passes through the gap 60 between the moving roll 54 and the anvil roll 56 having the aqueous solution 40 uniformly disposed thereon. Importantly, the structurally raised areas 36 and 38 of the cellulose substrate 22 (preferably applying an aqueous solution 40 containing the chemical papermaking additive 24) are directed toward the forward roll 54 And the remainder of the remaining cellulose substrate 22 is facing the anvil roll 56. By increasing or decreasing the clearance of the gap 60 between the moving roll 54 and the anvil roll 56, the structural composition of the cellulose substrate 22 when less and more of the aqueous composition 40 is in contact with each other It will be apparent to those skilled in the art that they can be printed and applied respectively to the raised areas. In addition, by changing the design of the metering roll 52, it is possible to vary the amount of the aqueous solution 40 applied to the cellulose substrate 22 in a constant gap 60. Optionally, the aqueous solution 40 is sprayed with the transfer roll 54 submerged in the aqueous composition 40 or the like, eliminating the need for the metering roll 52, or the metering roll 52 and the anvil roll. It can apply to the moving roll 54 by printing directly from the metering roll 52 to the base material 22 in the gap 60 formed between 56.

As the cellulose substrate 22 passes through the gap 60 between the transfer roll 54 and the anvil roll 56, the ridge 26 sufficient for the aqueous solution 40 to contact the circumference of the transfer roll 54. Applies only to the region of the cellulose substrate 22 having a. The moving roll 54 does not contact the portion of the cellulose substrate 22 remaining opposite the anvil roll 56. Thus no aqueous solution 40 is applied to this portion of the cellulose substrate 22.

By adjusting the margin space in the gap 60, different amounts of the aqueous solution 40 and ultimately the amount of the dried chemical papermaking additive 24 can be applied to the raised areas of the cellulose substrate 22. In general, for the embodiments described herein, it has been found that aqueous compositions 40 applied in the range of about 1 to about 500 mg per cm 2 of discontinuous region 36 are suitable.

Once the cellulose substrate 22 used in the paper structure 20 is selected to the consumer's taste, certain advantages become apparent. In particular, with areas 34 and 38 of different ridges 26 (one area 34 is in contact with the anvil roll 56 and the other area 38 is in contact with the moving roll 54) The cellulose substrate 22 according to provides several advantages that are not apparent to those skilled in the art. Once a particular pattern of aqueous solution 40 containing chemical papermaking additive 24 is deposited onto cellulose substrate 22 without the transfer roll 54 having to have a gravure pattern or radially extending protrusions. Can be. Generally, the patterned weighing roll 54 is more difficult and costly to manufacture than the unpatterned weighing roll 54.

A second advantage of the claimed invention is that it allows the pattern to be precisely applied to the area of cellulose substrate 22 where it is desirable for those who do not want to use the transfer roll 54 having the pattern to apply the chemical papermaking additive 24. Can be adjusted. This fit can be extremely difficult to achieve under more ideal fabrication conditions because different regions of the cellulose substrate 22 occur on close microscope scale. The actual manufacturing is much more complicated, since the tension, the basis weight of the cellulose substrate 22, and other fabrication factors typically change as the cellulose substrate 22 is drawn through the device 50, and thus the different regions 32 and This is because the pitch of 36) and the chance of misalignment may change. The method of producing the invention by the process described in FIG. 3 allows the chemical papermaking additive 24 to be precisely matched with the desired area of the cellulose substrate 22.

Third, if one wishes to change the pattern of chemical papermaking additive 24 applied to the cellulose substrate 22, a single device 50 with a moving roll 54 having a smooth, unpatterned perimeter can be used for multiple patterns. . A cellulose substrate 22 having a different structure is inserted in the gap 60 between the moving roll 54 and the anvil roll 56 and the margin space of the gap 60 is adjusted appropriately. The moving roll 54 may continue to have a smooth surface and any desired pattern by simply changing the cellulose substrate 22. Once the particular cellulose substrate 22 is selected, such in-fabrication flexibility could not be achieved in the prior art.

Several variant embodiments according to the invention are possible. For example, it is possible to construct a cellulose substrate 22 having essentially continuous network regions 32 and discontinuous regions 36 that differ depending on basis weight other than density. When such a cellulose substrate 22 is selected, commonly assigned U. S. Patent No. 4,514, 345 to Johnson et al. On April 30, 1985 or Trocan et al. On September 14, 1993. It can advantageously be produced using a forming wire according to FIG. 4 of U.S. Patent 4,514,345, commonly assigned to U.S. Patent 5,245,025 (the patents herein include cellulose substrates having regions of differing basis weights). 22) is incorporated by reference to show how to make them). Optionally, discontinuous regions 36 are possible with a number of different ridges 26 above (or below) the continuous network region 32. The chemical composition 24 may be applied only to the discrete areas 36 having a certain minimum ridge 26, or may be applied to each of the discrete areas 36 in an elevated-dependent amount.

Chemical paper additive

The chemical papermaking additive for use in the paper structure having the multi-density region of the present invention is preferably selected from the group consisting of rigid additives, absorbent additives, flexible additives, aesthetic additives, and mixtures thereof. Each of these types of additives will be described later.

A) Rigid Additives

The rigid additive is selected from the group consisting of permanent wet rigid resins, temporary wet rigid resins, dry rigid additives, and mixtures thereof.

If permanent wet stiffness is desired, chemical papermaking additives include polyamide epichlorohydrin, polyacrylamide, insoluble polyvinyl alcohol; Urea formaldehyde, polyethyleneimine, and chitosan polymers. Polyamide epichlorohydrin resins are cationic wet stiff resins that have been found to be particularly useful. Suitable types of such resins are described in US Pat. No. 3,700,623 to Keim, dated Oct. 24, 1972, and US Pat. No. 3,772,076, issued Nov. 13, 1973 to Keim. It is. One commercial source of useful polyamide-epichlorohydrin resins is Hercules Incorporated, Wilmington, Delaware, USA, and Kymeme 557H (trademark) is commercially available.

Polyacrylamide resins have also been found to have utility as wet rigid resins. These resins are disclosed in U.S. Patent No. 3,556,932 to Coscia et al. On January 19, 1971 and U. S. Patent No. 3,556,933 to Williams et al. On January 19, 1971. It is disclosed in the call. One commercial source of polyacrylamide resins is the American Cyanamid Company, Stanford, Connecticut, and Parez 631NC (trademark) is commercially available.

Other water soluble cationic resins useful in the present invention are urea formaldehyde and melamine formaldehyde resins. More common functional groups of such multifunctional resins are nitrogen containing groups such as amino and methylol groups attached to nitrogen. Polyethyleneimine type resins are also useful in the present invention.

If temporary wetting stiffness is required, chemical papermaking additives may be cationic dialdehyde starch-based resins such as Caldas produced by Japan Carlet, National Starch and Chemical Corporation. National Starch 78-0080 or Cobond 1000; And dialdehyde starch. Modified starch-based transient wet stiffness resins are also disclosed in US Pat. No. 4,675,394, issued to Sorarek et al. On June 23, 1987, which is incorporated herein by reference. Preferred temporary wet stiffness resins are disclosed in US Pat. No. 4,981,557 to Bjorkquist, issued January 1, 1991, which is incorporated herein by reference. Another example of a preferred temporary wet stiff resin is a modified polyacrylamide resin marketed by CyTec, namely Parez 750B.

If dry stiffness is desired, chemical papermaking additives may be selected from polyacrylamides (eg, a combination of Cypro 514 and Accostrength 711 produced by American Cyanamide, Wayne, NJ); Starch (eg corn starch or potato starch); Polyvinyl alcohol (Airvol 540 produced by Air Products Inc., Allentown, PA); Guar or locust bean gum; And / or carboxymethyl cellulose (Aqualon CMC-T, available from Aqualon Co., Wilmington, Delaware, USA.) In general, suitable starches for practicing the present invention Silver starch material is characterized by water solubility and hydrophilic Exemplary starch materials include corn starch and potato starch, and this example does not limit the range of suitable starch materials; waxes industrially known as amioca starch Sex corn starch is particularly preferred: Amioka starch is distinguished from conventional corn starch and is overall amylopectin, whereas conventional corn starch is amplopactin and amylose. It is described in detail in "Amioca-The Starch From Waxy Corn", HH Schopmeyer, Food Insudtries, Decem ber 1945, pp. 106-108 (Vol. pp. 1476-1478)] Starch is preferably in the form of granules but may be in the form of granules or dispersed Starch is preferably sufficiently cooked to induce swelling of the particles. More preferably, the starch particles are swollen by cooking just before the dispersion of the starch particles, such highly swelled starch particles are referred to as “completely cooked.” General dispersion conditions include starch particle size, crystallinity of particles and Depending on the amount of amylose present, for example, a fully cooked amioca starch is an aqueous solution of about 4% light viscosity of starch particles at about 190 ° F (about 88 ° C) for about 30 to about 40 minutes. Other starch materials that may be used are amino groups and methyl attached to nitrogen, commercially available from National Starch and Chemical Company of Bridgewater, NJ. Modified cationic starches, such as those modified to have nitrogen containing groups such as groups, such modified starch materials have been used primarily as pulp furnish additives to increase wet and / or dry stiffness. . However, when used by application to tissue paper webs according to the present invention, the effect on wet stiffness is reduced compared to the wet-end addition of the same modified starch material. Given that these modified starch materials are more economical than unmodified starch, the latter is generally preferred. These wet and dry rigid resins can be added to the pulp furnish as well as by the process described herein. It should be understood that the addition of chemical compounds such as the wet stiffness and transient wet stiffness resins discussed above to the pulp furnish is optional and not essential to the practice of the development of the present invention.

Rigid additives may be applied to the tissue paper web alone, prior to or after use, simultaneously with the flexible additive, the absorbent and / or aesthetic additive. At least an effective amount of the rigid additive, preferably starch, is treated to provide lint control and concomitant increase in stiffness relative to the non-binder upon drying, but preferably an equivalent sheet is applied to the sheet. Preferably, from about 0.01 to about 2.0% of the rigid additive, calculated on the basis of dry fiber weight, is retained in the dried sheet, and more preferably, from about 0.1 to about 1.0% by weight of the rigid additive, based on starch.

B) flexibility additives

The chemical flexible additive is selected from the group consisting of lubricants, plasticizers, cationic peptizers, noncationic peptizers, and mixtures thereof. Suitable peptizing agents for use as flexible additives in the present invention include cationic surfactants and noncationic surfactants, with cationic surfactants being preferred. Non-cationic surfactants include anionic, nonionic, zwitterionic and bipolar ionic surfactants. Preferably, the surfactant is substantially non-moving in situ after the tissue paper is manufactured to substantially avoid post-production changes in the nature of the tissue paper that may be caused by including the surfactant. This can be achieved, for example, by using surfactants having a melting point higher than the temperatures typically encountered during storage, shipping, sale and use of the tissue paper product of the present invention, for example, a melting point of at least about 50 ° C.

The amount of noncationic surfactant applied to the tissue paper web to impart this flexibility / tensile strength advantage is about 2% from the minimum effective amount needed to impart this benefit, based on a constant tensile strength in the final product. . Preferably, about 0.01 to about 2% noncationic surfactant is retained by the web, more preferably about 0.05 to about 1.0%, and most preferably about 0.05 to about 0.3%. The surfactant preferably has an alkyl chain having 8 or more carbon atoms. Exemplary anionic surfactants are linear alkyl sulfonates, and alkylbenzene sulfonates. Exemplary nonionic surfactants include alkylglycoside esters (such as Crodesta SL-40, commercially available from Croda Incorporated, New York, NY). Alkyl glycoside containing; Alkylglycoside ethers as described in US Pat. No. 4,011,389 to W.K.Langdon et al. On March 8, 1977; Alkyl polyethoxylated esters such as Pegosperse 200ML (registered trademark) commercially available from Glyco Chemicals, Inc., Greenwich, Connecticut; Alkylpolyethoxylated ethers and esters such as NeodoIR 25-12® available from Shell Chemical Company; Sorbitan esters, such as Span 60, commercially available from ICI America, Inc., ethoxylated sorbitan esters, propoxylated sorbitan esters, mixed ethoxylated / propoxylated sorbents No-ear esters, and polyethoxylated sorbitan alcohols (eg, Tween 60, available from ICI America, Inc.). Alkylpolyglycosides are particularly preferred for use in the present invention. The exemplary surfactants listed above are exemplary only and are not intended to limit the scope of the invention.

Any surfactant other than the chemical papermaking additive emulsifying surfactant material is hereinafter referred to as "surfactant" and any present surfactant, such as the emulsifying component of the emulsified chemical papermaking additive, is referred to hereinafter as "emulsifier". The surfactant is applied at the same time, before or after the tissue paper alone or with other chemical papermaking additives. In a general process, if other additives are present, the surfactant is applied to the cellulose substrate simultaneously with the other additives. It may be desirable to treat the peptizer-containing tissue paper with a relatively small amount of binder for lint control and / or increase in tensile strength. As used herein, "binder" refers to various wet and dry rigid additives known in the art. If a binder is used, it can be applied to the tissue paper simultaneously with or before and after use of the peptizing and absorption aids. Preferably, the binder is applied to the tissue web simultaneously with the peptizing agent (eg, the binder is included in a dilute aqueous solution applied to the tissue web).

If chemically flexible additives are required that act primarily to give a smooth feel, they can be selected from the following chemical groups:

Organic materials such as inorganic oils or waxes such as paraffin or canuba, or lanolin; Polysiloxanes (such as the compounds disclosed in US Pat. No. 5,059,282 to Ampulsky, which is incorporated herein by reference). Suitable polysiloxane compounds for use herein are detailed below.

The amount of polysiloxane compound applied to the tissue paper to impart the above described softness / smooth feel benefits is about 2 weights on a dry fiber basis from the minimum effective amount necessary to impart the benefit, based on a constant tensile strength for the final product. %to be. Preferably about 0.01 to about 2% of the polysiloxane compound is retained by the web, more preferably about 0.02 to about 1.0%, and most preferably about 0.03 to about 0.3%. The polysiloxane compound preferably has monomeric siloxane units of the formula:

Where

For each independent siloxane monomer phase unit R ₁ and R ₂ may each independently be hydrogen or any alkyl, aryl, alkenyl, alkaryl, aralkyl, cycloalkyl, halogenated hydrocarbon, or other radicals.

Any such radical may be substituted or unsubstituted.

The R ₁ and R ₂ radicals of any particular monomeric unit may be different from the corresponding functional groups of adjacent linked monomeric units. In addition, the polysiloxanes may be straight chain, branched chain and have a cyclic structure. The radicals R ₁ and R ₂ may independently be other siliconic functional groups such as, but not limited to, siloxanes, polysiloxanes, silanes and polysilanes. The radicals R ₁ and R ₂ may contain any of a variety of organic functional groups, including, for example, alcohol, carboxylic acid, aldehyde, ketone and amine, amide functional groups together with amino functional silicone compounds. Exemplary alkyl radicals are methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, octadecyl and the like. Exemplary alkenyl radicals are vinyl, allyl, and the like. Exemplary aryl radicals are phenyl, diphenyl, naphthyl and the like. Exemplary alkaryl radicals are toyl, xylyl, ethylphenyl and the like. Exemplary aralkyl radicals are benzyl, alpha-phenylethyl, beta-phenylethyl, alpha-phenylbutyl and the like. Exemplary cycloalkyl radicals are cyclobutyl, cyclopentyl, cyclohexyl, and the like. Exemplary halogenated hydrocarbon radicals are chloromethyl, bromoethyl, tetrafluoroethyl, fluoroethyl, trifluoroethyl, trifluorotolyl, hexafluoroxylyl and the like. References that disclose polysiloxanes are described in US Pat. No. 2,826,551 to Geen on March 11, 1958; U.S. Patent No. 3,964,500 to Drakoff, dated June 22, 1976; US Pat. No. 4,364,837 to Pader on December 21, 1982, US Pat. No. 5,059,282 to Ampulsky et al. On October 22, 1991; And British Patent 849,433 to Woolston, published September 28, 1960. All such patents are incorporated herein by reference. Further references cited herein are the following publications published by Petrarch Systems, Inc., 1984, which contains other examples and content of common polysiloxanes (see Silicon Compounds). , pp 181-217).

Polyethylene glycols (eg PEG 400), if chemically flexible additives are required that primarily act to plasticize the structure; Dimethylamine; And / or glycerin.

If primary catalyzed cationic chemical flexible additives are desired, cationic quaternary ammonium compounds [e.g., all dihydrogenated resin dimethyl ammonium methyl available from Witco Corporation, Greenwich, Connecticut, USA. Sulfate (DTDMAMS) or dihydrogenated resin dimethyl ammonium chloride (DTDMAC); Verocel 579 produced by Eka Nobel of Stansund, Sweden; Materials disclosed in US Pat. Nos. 4,351,699 and 4,447,294 to Osborn, which are incorporated herein by reference; And / or diester derivatives of DTDMAMS or DTDMAC.

In particular, quaternary ammonium compounds of formula 2 are suitable for use in the present invention:

_{(R 1) 4-m -N} + - [R 2] m X -

Where

m is 1 to 3;

Each R ₁ is a C ₁ -C ₈ alkyl group, hydroxyalkyl group, hydrocarbyl or substituted hydrocarbyl group, alkoxylated group, benzyl group or mixtures thereof;

Each R ₂ is a C ₉ -C ₄₁ alkyl group, hydroxyalkyl group, hydrocarbyl or substituted hydrocarbyl group, alkoxylated group, benzyl group or mixtures thereof;

X ⁻ is any softening agent-compatible anion.

Preferably, each R ₂ is C ₁₆ -C ₁₈ alkyl, most preferably each R ₂ is straight chain C ₁₈ alkyl. Preferably each R ₁ is methyl and X ⁻ is chloride or methyl sulfate. Optionally, R ₂ substituents can be derived from vegetable oil sources.

Biodegradable ester-functional quaternary ammonium compounds having the general formula (3) may also be used in the present invention:

_{(R 1) 4-m -N} + - [(CH 2) n -YR 2] m X -

Where

Each Y is -O- (O) C- or -C (O) -O-;

m is 1 to 3, preferably 2;

Each n is 1 to 4, preferably 2;

Each R ₁ substituent is a short chain C ₁ -C ₆ , preferably C ₁ -C ₃ , an alkyl group such as methyl (most preferably), ethyl, propyl, etc., a hydroxyalkyl group, a hydrocarbyl group, Benzyl groups or mixtures thereof;

Each R ₂ is a long chain, at least partially unsaturated (IV of at least about 5 to less than about 100, preferably from about 10 to less than about 85) C ₁₁ -C ₂₃ hydrocarbyl, or substituted hydrocarbyl substituents, and The ion, X ⁻ may be any softening agent-compatible anion, for example acetate, chloride, bromide, methylsulfate, formate, sulfate, nitrate and the like.

Preferably, most of R ₂ are fatty acids having a C ₁₈ -C ₂₄ chain length of at least 90%. More preferably, most of R ₂ is selected from the group consisting of fatty acids comprising at least 90% C ₁₈ , C ₂₂ and mixtures thereof.

Other types of suitable quaternary ammonium compounds are disclosed in European Patent No. 0 688 901 A2, assigned to Kimberley-Clark Corporation, which is hereby incorporated by reference December 12, 1995.

Tertiary amine softening compounds may also be used in the present invention. Examples of suitable tertiary amine softeners are disclosed in US Pat. No. 5,399,241, incorporated herein by reference on March 21, 1995, to James River Corporation.

C) Absorbent Additives

If absorption aids are desired that increase absorption, polyethoxylates (eg PEG 400); Alkyl ethoxylated esters (eg, 200 mL Pegosperse commercially available from Lonza Inc.); Alkyl ethoxylated alcohols such as Neodol; Alkyl polyethoxylated nonylphenols such as Igepal CO produced by Rhone-Poulenc / GAF; Ethoxylate trimethyl pentanediol and / or materials disclosed in US Pat. Nos. 4,959,125 and 4,940,513 to Spendel, which are incorporated herein by reference. If the surfactant peptizing agent softening agent reduces wetting, wetting agents, such as secondary surfactants, may be added to the coating solution. For example, sorbitan stearate ester can be mixed with an alkyl polyethoxylated alcohol to produce a soft, wettable paper.

Water soluble polyhydroxy compounds may also be used as absorption aids and / or wetting agents. Examples of water-soluble polyhydroxy compounds suitable for use in the present invention are glycerol, polyglycerols having an average molecular weight of about 150 to about 800 and about 200 to about 4000, preferably about 200 to about 1000, most preferably about Polyoxyethylene and polyoxypropylene having a weight average molecular weight of 200 to about 600. Particular preference is given to polyoxyethylenes having a weight average molecular weight of about 200 to about 600. Mixtures of the polyhydroxy compounds described above can also be used. For example, mixtures of glycerol and polyglycerols, mixtures of glycerol and polyoxyethylene, mixtures of polyglycerol and polyoxyethylene and the like are useful in the present invention. Particularly preferred polyhydroxy compounds are polyoxyethylenes having a weight average molecular weight of about 400. Such materials are commercially available from Union Carbide Company, Denver, Connecticut.

If absorption aids are required that reduce the absorption, these may be alkylketenedimers (eg, AquapelR 360XC emulsions manufactured by Hercules Incorporated, Wilmington, Delaware); Fluorocarbon (Scotch Guard, marketed by 3M in Minneapolis, Minnesota), hydrophobic silicone (PDMS DC-200, produced by Dow Corning, Midland, Midland, USA), fluorotel Romer (Zonyl 7040, commercially available from Dupont, Wilmington, Delaware).

Absorbent additives may be used alone or in combination with rigid additives. It has been found that starch-based rigid additives are preferred binders for use in the present invention. Preferably, the tissue paper is treated with aqueous starch solution. In addition to the reduced lining of the finished tissue paper product, small amounts of starch also give a normal improvement in the tensile stiffness of the tissue paper without imparting the rigidity (ie, stiffness) resulting from the addition of large amounts of starch. It is also improved stiffness / flexibility compared to sheets with increased tensile stiffness due to the purification of tissue paper, eg increased pulp, reinforced by traditional methods of increasing tensile stiffness or through the addition of dry stiffness additives. Provide a tissue paper having. This result is surprising because starch has traditionally been used for stiffness at the expense of flexibility, particularly in fields where flexibility is not an important feature, for example cardboard. In addition, starch has been used as a filler for printing paper and stationery to improve surface printability.

D) aesthetic additives

If aesthetic additives are desired, they are selected from the group consisting of inks, dyes, flavorings, opacifiers (eg TiO ₂ or calcium carbonate), fluorescent brighteners, and mixtures thereof.

The aesthetics of the paper can also be improved using the methods described herein. Inks, dyes and / or flavorings may be added to the aqueous composition, which is preferably applied continuously to the tissue paper web. Aesthetic additives may be used alone or in combination with wetting, softening and / or rigid additives.

Analytical Method

Analysis of the throughput of chemicals retained on the tissue paper web herein can be performed by any method used in the application art. For example, the amount of polysiloxane retained by tissue paper can be measured by solvent extraction of polysiloxane with an organic solvent followed by atomic absorption spectroscopy to determine the amount of silicon in the extract; The amount of nonionic surfactant, such as the amount of alkylglycoside, can be measured by extracting in an organic solvent and then measuring the amount of surfactant in the extract by gas chromatography; The amount of anionic surfactant, such as linear alkyl sulfonate, can be determined by water extraction followed by chromaticity analysis of the extract; The amount of starch can be measured by analyzing the amount of glucose by colorimetric analysis after amylase degradation into glucose. This method is exemplary and is not intended to exclude other methods that may be useful for determining the amount of a particular component retained by the tissue paper.

The hydrophilicity of tissue paper generally refers to the tendency of tissue paper to wet with water. The hydrophilicity of tissue paper can be somewhat quantified by determining the time period required for dry tissue paper to fully wet with water. This period is referred to as "wetting time". In order to provide a consistent and repeatable test at the wet time, the following procedure can be used to determine the wet time;

First, the conditioned sample unit sheet (environmental conditions for testing paper samples are 23 ± 1 ° C and 50 ± 2% RH as specified in TAPPI Method T 402), approximately 4-3 / 8 inches x tissue paper Providing a tissue paper structure of about 4-3 / 4 inches (about 11.1 cm × 12 cm);

Second, the sheet is folded in quarters and then rolled into a ball shape with a diameter of about 0.75 inches (about 1.9 cm) to about 1 inch (about 2.5 cm);

Third, all ball-shaped sheets are high on the body surface of distilled water at 23 ± 1 ° C. and the timer is run simultaneously;

Fourth, stop and read the timer when the ball-shaped sheet is fully wetted. Complete wetting is observed with the naked eye.

The preferred hydrophilicity of the tissue paper depends on its intended end use. Tissue paper used in various applications, for example toilet papers, is preferably completely wet for a relatively short period of time to prevent the pipes from clogging once the toilet water is poured out. Preferably the wetting time is less than 2 minutes. More preferably, the wetting time is less than 30 seconds. Most preferably, the wetting time is less than 10 seconds.

In embodiments of the invention, the hydrophilic properties of the tissue paper can of course be measured immediately after manufacture. However, a substantial increase in hydrophobicity may occur for two weeks after the tissue paper is produced, that is, two weeks after the paper is produced. Thus, the above mentioned wetting time is preferably measured at the end of this two week period. Thus, the wet time measured at the end of two weeks of aging at room temperature is referred to as "two weeks wet time".

As used herein, the "density of tissue paper" is an average density calculated by dividing the basis weight (mass / unit area) of the paper by a caliper and switching the units appropriately. As used herein, the caliper of the tissue paper is the thickness of the paper when introduced at a pressing load of 95 g / inch ² (15.5 g / cm 2). A suitable measuring instrument is a thickness test model 89-100 manufactured by Twin-Albert Instrument Co., 19154 Philadelphia, Pennsylvania, USA.

The following examples illustrate the implementation of the invention but are not intended to limit the scope of the invention.

Example 1

Small scale Fooddrinier paper machines are used in the practice of the present invention. A 3 wt.% Aqueous slurry of NSK (Northern Softwood Kraft) (commercially available as Grand Prairie from Weyerhaeuser Corporation, Tacoma, USA) was subjected to conventional re-pulper. Manufacture). A 2% solution of a temporary wet stiff resin (National Starch 78-0080, marketed by National Starch and Chemical Corporation, New York, NY) was used in NSK stock pipe at a rate of 0.75% based on the weight of the dry fibers. Add to The process of adsorbing the temporary wet stiff resin on the NSK fibers is enhanced by an in-line mixer. NSK slurry is diluted to about 0.2% light viscosity in a fan pump. Three weight percent aqueous slurry fibers of Eucalyptus (eg Aracruz, Brazil) are made with conventional recycled pulp makers. Eucalyptus slurry is diluted to about 0.2% hardness in a fan pump. The individual furnish components are sent to a separate layer in the head box (ie with NSK in the center layer and eucalyptus on the outer layer) and deposited on food linear wire and form a three layer initial web. Dewatered through the food linear wire and introduced into the deflector and vacuum box. The food linear wire consists of a 5-shed smooth weaving configuration with 33 machined monofilaments and 30 transverse machined monofilaments per cm, respectively. The initial wet web is moved from the food linear wire to the second papermaking belt at a fiber hardness of about 18% at the transition point. The second papermaking belt is an endless belt having a preferred network surface and deflection conduits. The paper belt is a porous woven fabric having 20 (MD) × 18 (CD) filaments per cm in a four shed bilayer design, as disclosed in US Pat. No. 5,334,289, issued to Trocan, which is hereby incorporated by reference. It is constructed by forming a photopolymeric network on the element. The filament has a diameter of about 22 mm in the machine direction and 28 mm in the transverse machine direction. The photopolymer fabric has about 35% knuckle area and 562 linear Idaho cells per square inch (87 cells per cm 2), which linear Idaho cell patterns are incorporated herein by reference. This is described in detail in FIG. 19 of US Pat. No. 5,514,523 to Trocan, dated May 7, 1996. The photosensitive resin used in this method is MEH-1000, ie methacrylate-urethane resin, marketed by MacDermid Imaging Technology Inc., Wilmington, Delaware. The paper belt has a total thickness of about 1.2 mm with a 0.2 mm photopolymer pattern extending over the woven foam member.

The initial web is conveyed onto a paper belt, exits the vacuum dehydration box, passes through a through blow-through predryer, and then the web is transferred onto a Yankee dryer. Other methods and machine conditions are listed below. The fiber hardness is about 27% after the vacuum dehydration box introduction and about 65% before being transferred onto the Yankee dryer by the action of the preliminary dryer. A creping adhesive comprising 0.25% aqueous solution of polyvinyl alcohol is spray applied by an applicator. The fiber hardness is increased to a 98% measure before dry creping the web to the doctor blade. The doctor blade is positioned to have an oblique angle of about 25 degrees and provide an impact angle of about 81 degrees relative to the Yankee dryer, the Yankee dryer operating at about 350 ° F. (177 ° C.). The Yankee dryer is operated at about 800 fpm (pits per minute) (about 244 m per minute). The dry creping web is then passed between two calender rolls. Two calendar rolls are biased together by roll weight and operated at a surface speed of about 660 fpm (about 201 m per minute). The calender web is wound on a reel (which also operates at a surface speed of 660 fpm) and ready for use.

An aqueous solution containing the chemical additive composition is continuously applied onto the paper-contacting surface of the paper belt before the paper belt contacts the initial web through the emulsion distribution roll. The aqueous chemical additive composition applied onto the biasing member by the dispensing roll contains five components. That is, water, Regal Oil (high speed turbine oil marketed by Texas Oil Company), Adogen TA 100 (Distearyldimethyl marketed by Witsuko Corporation) Ammonium chloride surfactant), cetyl alcohol (C ₁₆ linear fatty alcohols commercially available from The Procter & Gamble Company) and glycerol. The relative proportions of the five components are 6.1% by weight regal oil, 0.3% by weight adogen, 0.2% by weight cetyl alcohol, 31.1% by weight glycerol and the rest of the water. The volumetric flow rate of the aqueous chemical additive composition applied to the papermaking belt is about 0.50 gallons / hour / lateral deflection ft (about 6.21 L / hour / m). The wet web, when in contact with the aqueous chemical additive composition, has a fiber hardness of about 25% by weight of the total web.

Turn the web into a single layer tissue paper product. The tissue paper has a basis weight of about 18 pounds per 3000 ft ² of area, contains about 1% glycerol and about 1% regal oil primarily on the knuckle area of the tissue paper, about 0.2 dispensed through the tissue paper. % Temporary wet stiff resin. Importantly, the resulting tissue paper is soft and absorbent and is suitable for use as cosmetic tissue and / or toilet tissue.

Example 2

Small scale food linear paper machines are used in the practice of the present invention. A 3% by weight aqueous slurry of NSK (commercially available as a Grande Prayer from Weihauser Corporation, Tacoma, Wash.) Is prepared in a conventional recycled pulp mill. A 2% solution of a temporary wet stiff resin (National Starch 78-0080, marketed by National Starch and Chemical Corporation, New York, NY) was used in NSK stock pipe at a rate of 0.75% based on the weight of the dry fibers. Add to The process of adsorbing the temporary wet rigid resin onto the NSK fibers is enhanced by an in-line mixer. NSK slurry is diluted to about 0.2% hardness in a fan pump. Three weight percent aqueous slurry fibers of eucalyptus (eg, Aracruz, Brazil) are made with a conventional recycled pulp maker. Eucalyptus slurry is diluted to about 0.2% hardness in a fan pump. The individual furnish components are sent to a separate layer in the head box (ie with NSK in the center layer and eucalyptus on the outer layer) and deposited on food linear wire and form a three layer initial web. Dewatered through the food linear wire and introduced into the deflector and vacuum box. The food linear wire consists of a 5-shed smooth weaving configuration with 33 machined monofilaments and 30 transverse machined monofilaments per cm, respectively. The initial wet web is moved from the food linear wire to the second papermaking belt at a fiber hardness of about 18% at the transition point. The second papermaking belt is an endless belt having a preferred network surface and a deflection conduit. The paper belt is a porous woven fabric having 20 (MD) × 18 (CD) filaments per cm in a four shed bilayer design, as disclosed in US Pat. No. 5,334,289, issued to Trocan, which is hereby incorporated by reference. It is constructed by forming a photopolymeric network on the element. The filament has a diameter of about 22 mm in the machine direction and 28 mm in the transverse machine direction. The photopolymer fabric has about 35% knuckle area and has 562 linear Idaho cells per square inch (87 cells per cm 2), and this linear Idaho cell pattern is delineated on May 7, 1996, incorporated herein by reference. This is described in detail in FIG. 19 of US Pat. No. 5,514,523 to Khan. The photosensitive resin used in this method is MEH-1000, ie methacrylate-urethane resin, commercially available from Mcdermid Imaging Technology, Inc., Wilmington, Delaware. The paper belt has a total thickness of about 1.2 mm with a 0.2 mm photopolymer pattern extending over the woven foam member.

The initial web is conveyed onto a paper belt, exits the vacuum dehydration box, passes through a fully blown-to-complete predryer, and then the web is transferred onto a Yankee dryer. Other methods and machine conditions are listed below. Fiber hardness is about 27% after vacuum dehydration box introduction and about 65% before being transferred onto the Yankee dryer by the action of the preliminary dryer. A creping adhesive comprising 0.25% aqueous solution of polyvinyl alcohol is spray applied by an applicator. The fiber hardness is increased to a 98% measure before dry creping the web to the doctor blade. The doctor blade is positioned to have an oblique angle of about 25 degrees and provide an impact angle of about 81 degrees relative to the Yankee dryer, the Yankee dryer operating at about 350 ° F. (177 ° C.). The Yankee dryer is operated at about 800 fpm (pits per minute) (about 244 m per minute). The dry creping web is then passed between two calender rolls. Two calendar rolls are biased together by roll weight and operated at a surface speed of about 660 fpm (about 201 m per minute). The calender web is wound on a reel (which also operates at a surface speed of 660 fpm) and ready for use.

An aqueous solution containing the chemical additive composition is continuously applied onto the top of the calender roll. The aqueous chemical additive composition applied by the calender roll contains three components. That is, water, a quaternary ammonium compound (e.g., di (hydrogenated) resin dimethyl ammonium methyl sulfate sold under the trade name Varisoft 137 by Witsco Corporation) and glycerol. The relative proportions of the three components are 10% by weight of Barisoft 137, 40% by weight of glycerol and the remainder of water. The web, when in contact with the aqueous chemical additive composition, has a fiber hardness of about 98% based on the total web weight.

Turn the web into a single layer tissue paper product. The tissue paper has a basis weight of about 18 pounds per 3000 ft ² of area, contains about 1% glycerol and about 1% regal oil primarily on the knuckle area of the tissue paper, about 0.2 dispensed through the tissue paper. % Temporary wet stiff resin. Importantly, the resulting tissue paper is soft and absorbent and is suitable as a cosmetic tissue and / or toilet tissue.

Example 3

Small scale food linear paper machines are used in the practice of the present invention. A 3% by weight aqueous slurry of NSK (commercially available as a Grande Prayer from Weihauser Corporation, Tacoma, Wash.) Is prepared in a conventional recycled pulp mill. A 2% solution of a temporary wet stiff resin (National Starch 78-0080, marketed by National Starch and Chemical Corporation, New York, NY) was used in NSK stock pipe at a rate of 0.75% based on the weight of the dry fibers. Add to The process of adsorbing the temporary wet rigid resin onto the NSK fibers is enhanced by an in-line mixer. NSK slurry is diluted to about 0.2% hardness in a fan pump. Three weight percent aqueous slurry fibers of eucalyptus (eg, Aracruz, Brazil) are made with a conventional recycled pulp maker. Eucalyptus slurry is diluted to about 0.2% hardness in a fan pump. The individual furnish components are sent to a separate layer in the head box (ie with NSK in the center layer and eucalyptus on the outer layer) and deposited on food linear wire and form a three layer initial web. Dewatered through the food linear wire and introduced into the deflector and vacuum box. The food linear wire consists of a 5-shed smooth weaving configuration with 33 machined monofilaments and 30 transverse machined monofilaments per cm, respectively. The initial wet web is moved from the food linear wire to the second papermaking belt at a fiber hardness of about 18% at the transition point. The second papermaking belt is an endless belt having a preferred network surface and a deflection conduit. The paper belt is a porous woven fabric having 20 (MD) × 18 (CD) filaments per cm in a four shed bilayer design, as disclosed in US Pat. No. 5,334,289, issued to Trocan, which is hereby incorporated by reference. It is constructed by forming a photopolymeric network on the element. The filament has a diameter of about 22 mm in the machine direction and 28 mm in the transverse machine direction. The photopolymer fabric has about 35% knuckle area and has 562 linear Idaho cells per square inch (87 cells per cm 2), and this linear Idaho cell pattern is delineated on May 7, 1996, incorporated herein by reference. This is described in detail in FIG. 19 of US Pat. No. 5,514,523 to Khan. The photosensitive resin used in this method is MEH-1000, ie methacrylate-urethane resin, commercially available from Mcdermid Imaging Technology, Inc., Wilmington, Delaware. The paper belt has a total thickness of about 1.2 mm with a 0.2 mm photopolymer pattern extending over the woven foam member.

The initial web is conveyed onto a paper belt, exits the vacuum dehydration box, passes through a fully blown-to-complete predryer, and then the web is transferred onto a Yankee dryer. Other methods and machine conditions are listed below. Fiber hardness is about 27% after vacuum dehydration box introduction and about 65% before being transferred onto the Yankee dryer by the action of the preliminary dryer. A creping adhesive comprising 0.25% aqueous solution of polyvinyl alcohol is spray applied by an applicator. The fiber hardness is increased to a 98% measure before dry creping the web to the doctor blade. The doctor blade is positioned to have an oblique angle of about 25 degrees and provide an impact angle of about 81 degrees relative to the Yankee dryer, the Yankee dryer operating at about 350 ° F. (177 ° C.). The Yankee dryer is operated at about 800 fpm (pits per minute) (about 244 m per minute). The dry creping web is then passed between two calender rolls. Two calendar rolls are biased together by roll weight and operated at a surface speed of about 660 fpm (about 201 m per minute). The calender web is wound on a reel (which also operates at a surface speed of 660 fpm) and ready for use.

An aqueous solution containing the chemical additive composition is continuously applied onto the knuckle region of the paper belt before the paper belt contacts the initial web through the emulsion distribution roll. The aqueous chemical additive composition applied onto the knuckle region by the dispensing roll contains five components. Ie water, regal oil (high speed turbine oil marketed by Texco Oil Company), adogen TA 100 (distearyldimethyl ammonium chloride surfactant marketed by Witsuko Corporation), cetyl alcohol (The Procter & Gamble Campa) C ₁₆ linear fatty alcohols commercially available from Ni.) And water soluble dye compositions. The relative proportions of the five components are 6.1% by weight legal oil, 0.3% by weight agenene, 0.2% by weight cetyl alcohol, 0.2% by weight water soluble dye composition and the remainder of the water. The volumetric flow rate of the aqueous chemical additive composition applied to the papermaking belt is about 0.50 gallons / hour / lateral deflection ft (about 6.21 L / hour / m). The wet web, when in contact with the aqueous chemical additive composition, has a fiber hardness of about 25% by weight of the total web.

Turn the web into a single layer tissue paper product. Tissue paper has a basis weight of about 18 pounds per 3000 ft ² of area and includes about 0.2% of the temporary wet stiff resin. Importantly, the resulting tissue paper is soft, absorbent, has an improved aesthetic and is suitable for use as a cosmetic tissue and / or toilet tissue.

Example 4

Small scale food linear paper machines are used in the practice of the present invention. A 3% by weight aqueous slurry of NSK (commercially available as a Grande Prayer from Weihauser Corporation, Tacoma, Wash.) Is prepared in a conventional recycled pulp mill. A 2% solution of a temporary wet stiff resin (National Starch 78-0080, marketed by National Starch and Chemical Corporation, New York, NY) was used in NSK stock pipe at a rate of 0.75% based on the weight of the dry fibers. Add to The process of adsorbing the temporary wet rigid resin onto the NSK fibers is enhanced by an in-line mixer. NSK slurry is diluted to about 0.2% hardness in a fan pump. Three weight percent aqueous slurry fibers of eucalyptus (eg, Aracruz, Brazil) are made with a conventional recycled pulp maker. Eucalyptus slurry is diluted to about 0.2% hardness in a fan pump. The individual furnish components are sent to a separate layer in the head box (ie with NSK in the center layer and eucalyptus on the outer layer) and deposited on food linear wire and form a three layer initial web. Dewatered through the food linear wire and introduced into the deflector and vacuum box. The food linear wire consists of a 5-shed smooth weaving configuration with 33 machined monofilaments and 30 transverse machined monofilaments per cm, respectively. The initial wet web is moved from the food linear wire to the second papermaking belt at a fiber hardness of about 18% at the transition point. The second papermaking belt is an endless belt having a preferred network surface and a deflection conduit. The paper belt is a porous woven fabric having 20 (MD) × 18 (CD) filaments per cm in a four shed bilayer design, as disclosed in US Pat. No. 5,334,289, issued to Trocan, which is hereby incorporated by reference. It is constructed by forming a photopolymeric network on the element. The filament has a diameter of about 22 mm in the machine direction and 28 mm in the transverse machine direction. The photopolymer fabric has about 35% knuckle area and has 562 linear Idaho cells per square inch (87 cells per cm 2), and this linear Idaho cell pattern is delineated on May 7, 1996, incorporated herein by reference. This is described in detail in FIG. 19 of US Pat. No. 5,514,523 to Khan. The photosensitive resin used in this method is MEH-1000, ie methacrylate-urethane resin, commercially available from Mcdermid Imaging Technology, Inc., Wilmington, Delaware. The paper belt has a total thickness of about 1.2 mm with a 0.2 mm photopolymer pattern extending over the woven foam member.

The initial web is conveyed onto a paper belt, exits the vacuum dehydration box, passes through a fully blown-to-complete predryer, and then the web is transferred onto a Yankee dryer. Other methods and machine conditions are listed below. Fiber hardness is about 27% after vacuum dehydration box introduction and about 65% before being transferred onto the Yankee dryer by the action of the preliminary dryer. A creping adhesive comprising 0.25% aqueous solution of polyvinyl alcohol is spray applied by an applicator. The fiber hardness is increased to a 98% measure before dry creping the web to the doctor blade. The doctor blade is positioned to have an oblique angle of about 25 degrees and provide an impact angle of about 81 degrees relative to the Yankee dryer, the Yankee dryer operating at about 350 ° F. (177 ° C.). The Yankee dryer is operated at about 800 fpm (pits per minute) (about 244 m per minute). The dry creping web is then passed between two calender rolls. Two calendar rolls are biased together by roll weight and operated at a surface speed of about 660 fpm (about 201 m per minute). The calender web is wound on a reel (which also operates at a surface speed of 660 fpm) and ready for use.

The aqueous solution containing the chemical additive composition is applied continuously onto the surface of the Yankee dryer by the spraying system prior to the movement of the initial web. The aqueous chemical additive composition applied by the spray system onto the surface of the Yankee dryer contains three components. Ie, water, Airball 540 (polyvinyl alcohol sold by Air Products Inc., Allentown, PA) and Cypro 711 (polyacrylamide supplied by American Cyanamide, Wayne, NJ) Dry rigid resin). The relative proportions of the three components are 0.125% by weight polyvinyl alcohol, 0.125% by weight polyacrylamide dry rigid resin and the remainder of water. The volume flow rate of the aqueous chemical additive composition applied on the surface of the Yankee dryer is about 0.11 gallons / minute / lateral ft. The wet initial web has an overall average water content of about 0.67 pounds of water per pound of fiber.

Turn the web into a single layer tissue paper product. The tissue paper has a basis weight of about 18 pounds of fiber per 3000 ft ² of area and contains about 0.01% dry stiff resin primarily distributed over the high density region of the tissue product. Importantly, the resulting tissue paper is soft and absorbent, has an improved aesthetic and is suitable for use as a cosmetic tissue and / or toilet tissue.

Claims (29)

A cellulose substrate having a relatively high density first region and a relatively low density second region, each disposed in a non-irregular repeating pattern; And Immobilized chemical papermaking additive disposed on one of the relatively high density first regions and one of the relatively low density second regions Paper structure improved physical properties by the chemical comprising a. A cellulose substrate comprising a first region comprising essentially a continuous high density network and a second region of low density discontinuity; And Immobilized chemical papermaking additive disposed on the low density region Paper structure improved physical properties by the chemical comprising a. The method of claim 2, A paper structure in which discontinuous low density regions and essentially continuous network structures lie in two different planes. The method of claim 1, A paper structure wherein the chemical papermaking additive is selected from the group consisting of rigid additives, absorbent additives, flexible additives, aesthetic additives, and mixtures thereof. The method of claim 4, wherein Paper structure wherein the chemical papermaking additive is a flexible additive. The method of claim 5, And the flexible additive is selected from the group consisting of lubricants, plasticizers, cationic peptizers, noncationic peptizers, and mixtures thereof. The method of claim 6, Paper structure wherein the flexible additive is a noncationic peptizer. The method of claim 7, wherein A paper structure wherein the noncationic peptizing agent is selected from the group consisting of sorbitan esters, ethoxylated sorbitan esters, propoxylated sorbitan esters, mixed ethoxylated / propoxylated sorbitan esters and mixtures thereof. The method of claim 6, Paper structure wherein the flexible additive is a cationic softener. The method of claim 9, Paper structure wherein the cationic softener is a quaternary ammonium compound. The method of claim 9, Paper structure wherein the cationic softener is a diester quaternary ammonium compound. The method of claim 4, wherein A paper structure wherein the chemical papermaking additive is a rigid additive. The method of claim 12, The paper structure wherein the rigid additive is selected from the group consisting of permanent wet stiff resins, temporary wet stiff resins, dry rigid additives, and mixtures thereof. The method of claim 13, Wherein the rigid additive is a permanent wet stiff resin selected from the group consisting of polyamide-epichlorohydrin resins, polyacrylamide resins, and mixtures thereof. The method of claim 14, Paper structure wherein the rigid additive is a starch-based transient wet stiff resin. The method of claim 4, wherein Paper structure wherein the chemical papermaking additive is an absorbent additive. The method of claim 16, Paper structure wherein the absorbent additive is selected from the group consisting of polyhydroxy compounds, polyethoxylates, alkylethoxylated esters, alkylethoxylated alcohols, alkylpolyethoxylated nonylphenols, ethoxylate trimethyl pentanediols and mixtures thereof . The method of claim 17, Paper structure wherein the absorbent additive is an alkyl ethoxylated alcohol. The method of claim 17, A paper structure wherein the absorbent additive is a polyhydroxy compound. The method of claim 19, Paper structure wherein the polyhydroxy compound is selected from the group consisting of glycerol, polyglycerol, polyoxyethylene, polyoxypropylene and mixtures thereof. The method of claim 4, wherein Paper structure wherein the chemical papermaking additive is an aesthetic additive. The method of claim 21, The paper structure wherein the esthetic additive is selected from the group consisting of inks, dyes, flavors, opacifiers, fluorescent brighteners and mixtures thereof. The method of claim 22, Paper structure wherein the esthetic additive is a dye. The method of claim 6, Paper structure wherein the lubricity additive comprises a silicone compound. The method of claim 24, The paper structure wherein the silicon compound is amino functional silicone. A cellulose substrate having essentially continuous relatively high density networked regions and discontinuous relatively low density regions disposed therein, each disposed in a non-irregular repeating pattern; And A immobilized chemical papermaking additive disposed on one of said relatively high density regions and one of said relatively low density regions; The essentially continuous relatively high density network area defines a first ridge and the discontinuous relatively low density area defines a second ridge. Paper structure with improved properties by through-air-dried chemicals. The method of claim 1, A paper structure produced according to a method comprising the step of printing a chemical papermaking additive on one of the first and second regions by contact with a roll. The method of claim 2, A paper structure made according to a method comprising the step of printing a chemical papermaking additive on a low density region by contact with a roll. The method of claim 26, A paper structure produced according to a method comprising the step of printing a chemical papermaking additive on one of a relatively high density area and a relatively low density area by contact with a roll.