MXPA01000460A - Paper towel - Google Patents

Abstract

The present invention may provide a towel (10) desirably including first (14) and second (18) layers having cellulosic fibers and a repellant agent. The first and second layers may substantially sandwich a third layer (22) having cellulosic fibers with higher absorbency than the first and second layers. All three layers may form a single ply (26).

Description

PAPER TOWEL FIELD OF THE INVENTION This invention relates generally to the field of papermaking and more specifically to a high utility towel.

BACKGROUND After hand washing, typically a paper-based hand towel is used to dry hands; particularly in public bathrooms. Frequently, a towel is used until its outer layers are moistened. At that point the paper towel is discarded and another paper towel can be dispensed to continue drying. Unfortunately, this practice fails to use the full absorbent capacity of the paper towel. Even when the outer layers of the used towels are wet, they can still have absorbent capacity. As a result, the failure to use this capacity wastes the towels.

Therefore, a hand towel that remains dry on its surface will reduce the use of hand towels by allowing the use of essentially the full absorbency capacity of the towel, thus reducing the consumption and waste rates of towels.

DEFINITIONS As used herein, the term "comprises" refers to a part or parts of a whole, but does not exclude other parts. The term "includes" has the same meaning and is interchangeable with the terms "includes" and "has".

As used herein, the term "repellent agent" refers to an agent that resists the absorption of a liquid, desirably an aqueous liquid. The repellent agent can be hydrophobic and includes materials such as sizing agents, silicon, waxes and latexes.

As used herein, the term "latex" refers to a colloidal water dispersion of higher polymers from sources related to natural rubber, such as Hevea tree sap, or synthetic upper polymers that look like natural rubber. Synthetic latexes are made by emulsion polymerization techniques of styrene-butadiene copolymer, acrylate resins, polyvinyl acetate, and similar materials.

As used herein, the term "silicon" refers to a non-metallic element or to any compounds that incorporate this element, such as the siloxane organ. The siloxane organ is any of a large group of siloxane polymers based on a structure consisting of alternating silicon and oxygen atoms with several organic radicals attached to the silicon. An example of the silicon material is sold under the trademark DOW 929 from Dow Chemical, of Midland, Michigan.

As used herein, the term "layer" refers to a single thickness, course, stratum, or fold that lies or remains above or below another. An example multilayer structure is shown in Figure 1 where a towel 10 includes five layers 14, 18, 22, 30 and 34.

As used herein, the term "stratum" refers to a material produced from a headbox having one or more layers. An example towel having a two-layer structure is shown in Figure 2, where a towel 50 includes two layers 54A and 54B.

As used herein, the term "wax" refers to an aqueous emulsion of small particles held in suspension by an emulsifying agent. Exemplary waxes include paraffin waxes, microcrystalline wax, or other waxes. A exemplary wax composition that can be printed on paper products is described in U.S. Patent Nos. 5,601,871, 5,614,293, and 5,665,426, which are incorporated herein by reference.

As used herein, the term "sizing agent" refers to any chemical that inhibits liquid penetration of the cellulosic fiber structures. Suitable sizing agents are described in the text entitled "Cardboard and Paperboard Manufacturing", second edition, Volume III, edited by R. G. MacDonald and J. N. Franklin, which is incorporated herein by reference.

Particularly suitable sizing agents are alkali or acid sizing agents such as rosin acid, alkenyl succinic anhydride, alkyl ketone dimers, alkenol ketene dimers of the formula: R, - CH C - CH - R, 0 -. 0 - C 0 where R? and R2 are C16-C18 aliphatic carbon chains, which may be the same or different. Exemplary commercially available sizing agents of this type are HERCON 79, HERCON 1332, and PRECIS 3000 from Hercules, Inc., of Wilmington, Delaware.

As used herein, the term "cellulose" refers to a higher polymer of natural carbohydrate (polysaccharide) which has the chemical formula (C5H10O5) n and which consists of d anhydroglucose units linked by an oxygen bond to form long molecular chains which they are essentially linear. The natural sources of cellulose include deciduous coniferous trees, cotton, flax, esparto grass, benzene, straw, jute, hemp and bagasse.

As used herein, the term "pulp" refers to the processed cellulose.

As used herein, the term "absorbency" refers to the rate that a material completely soaks a given amount of a liquid over a specified period of time. The absorbency rate of unsized papers can be measured using the ASTM test procedure number D 824-94 and sizing papers can be measured using the ASTM test procedure number D 779.

As used herein, the term "absorbency gradient" refers to the different absorbency of the various layers or layers in a towel product. Desirably, the inner layers or layers of the towel have greater absorbency than the outer layers.

As used herein, the term "transmission" refers to the rate at which a liquid is absorbed into material as a result of capillary action. The results are typically reported as centimeter per minute. During the test, about 25 millimeters per about 200 millimeters of sample free of bends, wrinkles and distortions is suspended vertically and partially in liquid, typically oil or water, at around 23 degrees Celsius and 50 percent relative humidity. Frequently, about 25 millimeters of the sample length of 200 millimeters are immersed in the liquid. A weight can be attached to this end to prevent curling. The height of the front edge of liquid to the liquid surface is recorded in several time intervals, such as 0.25, 0.5, 0.75 and 1.0 minutes to determine the transmission rate.

As used herein, the term "transmission gradient" refers to the different transmission capacity of several layers or layers in a towel product, desirably, the inner layers or layers of the towel have greater transmission than the outer layers.

As used herein, the term "sulfite pulp" refers to the pulp chemically processed with a mixture of sulfurous acid and bisulfite ion, which attacks and solubilizes the lignin in the pulp supply.

As used herein, the term "bleached quimotermomechanical pulp" refers to processing the cellulosic material with steam, pressure and sodium sulfite or hydrogen peroxide to soften the wood lignin between and within the cell walls. In addition, the alkaline peroxide bleach is added to further soften and brighten the cellulose fibers. The term bleached quimotermomecánica pulp can be abbreviated hereinafter as "BCTMP".

As used here, the term "basis weight", (hereinafter referred to as "BW") is the weight per unit area of a sample and can be reported as gram-force per square meter (from here on forward it can be abbreviated as "gsm." The basis weight can be measured using the test procedure ASTM D 3776-96 or the TAPPI test method T-220.

SYNTHESIS OF THE INVENTION The problems and needs described above are examined by the present invention which provides a towel that desirably includes the first and second layers having the cellulosic fibers and a repellent agent. The first and second layers may have in essentially sandwich form a third layer having cellulosic fibers with an absorbency greater than that of the first and second layers. All three layers can form a single stratum.

In addition, the towel may also include the fourth and fifth layers respectively placed between the first and third layers and between the second and third layers. The fourth and fifth layers may have cellulosic fibers with a transmission superior to that of the first and second layers.

In addition, the repellent agent may be wax, latex, a sizing agent, and / or silicon. In addition, the repellent agent can be printed and / or sprayed on at least one of the first or second layers. In addition, the repellent agent can be mixed with the fibers of at least one of the first or second layers in a headbox. What is more, the first or second layers may include sulphite pulp or bleached quimotermomechanical pulp and the towel may have a basis weight of from about 8 grams force per square meter to about 59 grams force per square meter. In addition, the third layer may have a higher absorbency and a transmission greater than that of the fourth and fifth layers.

Another embodiment of a towel may include a first layer that also includes a first layer having cellulosic fibers and a repellent agent, a second layer having cellulosic fibers with a transmission greater than that of the first layer, and a third layer having fibers cellulose with an absorbency superior to that of the first and second layers. The second layer can be placed near the first layer and the third layer can be placed close to the second layer. A second stratum can be joined to the first stratum and an identical image thereof is generally.

In addition, the repellent agent can be wax, latex, a sizing and / or silicon people. In addition, the repellent agent can be printed and / or sprayed on at least one of the first or second layers. In addition, the repellent agent can be 'mixed with the fibers of at least one of the first or second layers in a headbox. What is more, the first or second layers may include sulfite pulp or bleached quimotermomechanical pulp and the towel may have a basis weight of from about 8 grams force per square meter to about 59 grams force per square meter. In addition, the third layer may have a transmission greater than that of the second layer.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view amplified, but not necessarily to scale, of an incorporation of a towel.

Figure 2 is an enlarged side elevational view, but not necessarily to scale, of another embodiment of a towel.

Figure 3 is an illustration of an example process for making a towel.

Figure 4 is an illustration of another example process for making a towel.

DETAILED DESCRIPTION OF THE PREFERRED INCORPORATIONS Referring now to the drawings, the like reference numerals designate a corresponding structure through the views and like reference numbers used in conjunction with sequentially ordered upper case letters refer to a series of essentially identical items or components. Referring in particular to Figures 1-2, there are two additions of the towels 10 and 50.

The towel 10 can include a first layer 26, further includes a first layer 14, a second layer 18, a third layer 22, a fourth layer 30 and a fifth layer 34. The first and second layers 14 and 18 can be placed over the outer surfaces of the towel 10. These layers 14 and 18 can be formed from pulp, such as sulfite pulp and bleached chemo-thermomechanical pulp, even when other pulps can also be used. Frequently, sulphite pulp and bleached quimotermomechanical pulp are more hydrophobic than kraft fibers, Desirably, the first and second layers 14 and 18 are patterned with a repellent agent to provide hydrophobic properties, such as lacking an affinity for water or water-based solutions., even when the agent can be mixed with the fibers or can be sprayed on the fibers as well. The repellent agent can repel liquids by filling the gap gaps in the fibrous structure of layers 14 and 18 or by coating individual fibers preventing liquids from being absorbed and passing through the fibers into the fibrous structure. . An exemplary repellent agent is a hydrophobic chemical sold under the trade designation REACTOPAQUE by Sequa Chemicals, Inc., at One Sequa Drive, Chester, South Carolina 29706. The amount of the repellent agent added to the fibers can be from about from 1 to about 30 pounds per ton of fiber, more specifically from about 1.2 to about 20 pounds per ton of fiber, and even more specifically from about 2 to about 10 pounds per ton of fiber.

The patterned coating can provide enough open pores for the liquid to penetrate the inner layers 22, 30 and 34, but prevents water absorption in the fibers of the layers 14 and 18. Therefore, the outer layers 14 and 18 of the towel 10 remains dry during use allows the transfer of liquid to the inner layers 22, 30 and 34 of the towel 10, thereby allowing the use d essentially the full absorbent capacity of the towel 10. The repellent agents may include waxes, latex, silicon sizing agents.

Frequently sizing agents are commonly added to control the penetration of aqueous liquids into paper or into other fibrous structures. In many cases, some resistance is required for the end use. When surface treatments are applied with conventional equipment, such as sprinklers or applicators, sizing is often required on a base sheet to control the intake of the aqueous solution. Paper classes such as butcher wrap, milk box, liner board, bleached and unbleached bag, fine paper, cylinder board, newspaper and corrugated media are routinely subjected to sizing.

Internal sizing agents, which are those applied to the fibers within the paper structure, provide a reduced rate of penetration by retarding the rate of flow through the capillary vessels of the interfiber, as measured by the process of ASTM D 779-94 test. When sizing is achieved, the contact angle at the fiber surface is increased, as measured by the ASTM D 5725-95 test procedure or the TAPPI T-458 test method. Internal sizing agents work through the use of a low surface energy, which when clamped to the surface of the cellulose, reduces the surface energy of the fiber surface.

The amount of sizing agent added to the fibers in layers 14 and 18 can be from about 1 to about 10 pounds per ton of fiber, more specifically from about 1.5 to about 3 pounds per ton of fiber, and even more specifically from about 2 to about 2.5 pounds per ton of fiber.

The fourth and fifth layers 30 and 34 can be placed inside, respectively, of the first and second layers 14 and 18, and have the third layer 22 in sandwich form. Desirably, these layers 30 and 34 can be formed from a cellulosic material and having absorption and transmission properties superior to those of layers 14 and 18 to transfer the liquid to layer 22. Desirably, these layers 30 and 34 will be thin in relation to the other layers 14, 18 and 22 to transfer the liquid .

Desirably, the third layer 22 may reside in the center of the towel 10 and may include cellulosic fibers.

Desirably, the third layer 22 has a higher transmission absorption properties than those of the layers 14, 18, 30 and 34, thereby creating transmission and absorption gradients in the towel 10. These gradients pull the liquid from the towel 10. to other surfaces of its interior, where it is spread and absorbed through the layer 22. The gradients also prevent the liquid from migrating from the inside to the surface.

The basis weight of the towel 10 can vary from about 8 grams force per square meter to about 59 grams force per square meter, desirably from about 17 grams force per square meter to about 34 grams force per square meter, and more desirably about 27 grams force per square meter. The towel 10 is made of cellulose materials that can be modified by various treatments such as, for example, thermal, mechanical and / or chemical treatments. It is contemplated that the reconstituted cellulose material may be used and / or mixed with another cellulose material. Desirably, no synthetic fibers are woven into the cellulosic material.

The towel 50 may include a first layer 54A having a first layer 58A, a second layer 62A, and a third layer 66A and a second layer 54B having a first layer 58B, a second layer 62B and a third layer 66B. The second layer 54B can have an essentially identical image 86 of the first layer 54A forming a palindromic structure. As a result, only the first stratum 54A will be discussed in detail hereinafter.

Desirably, stratum 54A includes first layer 58A, second layer 62A and third layer 66A. The first layer 58A can be placed on the outer surfaces of the towel 50 and can be formed from the pulp, such as the sulfite pulp and the bleached quimotermomechanical pulp, even when other pulps can also be used.

Desirably, the first layer 58A is patterned with a repellent agent to provide hydrophobic properties, even when the agent can be mixed with the fibers or can be sprayed onto the fibers as well. The repellent agent can repel liquids by filling the gap gaps in the fibrous structure of the layer 58A or coating the individual fibers preventing liquids from being absorbed and passing through the fibers into the fibrous structure. An example repellent agent is a hydrophobic chemical sold under the trade designation REACTOPAQUE from Sequa Chemicals, Inc., at One Sequa Drive, Chester, South Carolina 29706. The amount of the repellent agent added to the fibers may be from about 1 to about 30 pounds per ton of fiber, more specifically from about 1.2 to about 20 pounds per ton of fiber, and even more specifically from about 2 about 10 pounds per ton of fiber.

The patterned coating can provide enough open pores for the liquid to penetrate the interior of the towel 50, but prevents water absorption in the fibers of the outer layer 58A. Therefore, the outer layer 58 remains dry during use and allows for the transfer of liquid into the towel 50, thereby allowing the use of the complete absorbent capacity of the towel 50. The repellent agents may include waxes, latex, silicon and sizing agents.

Frequently the sizing agents are commonly added to control the penetration of aqueous liquids inside the paper or inside other fibrous structures. In many cases, some resistance is required for the end use. When surface treatments are applied with conventional equipment, such as sprinklers or applicators, frequently the sizing is required on the base sheet to control the intake of the aqueous solution. Paper classes such as butcher wrap, milk box, liner board, bleached and unbleached bag, fine paper, cylinder board, newspaper and corrugated media are routinely subjected to sizing.

The internal sizing agents, which are those applied to the fibers within the paper structure, provide a reduced rate of penetration by slowing the rate of flow through the capillary vessels of the interfiber, as measured by the process of ASTM D 779-94 test. When sizing is achieved, the contact angle at the fiber surface is increased, as measured by the ASTM D 5725-95 test procedure or the TAPPI T-458 test method. Internal sizing agents work through the use of low surface energy, which when clamped to the surface of the cellulose, reduces the surface energy of the fiber surface.

The amount of the sizing agent added to the fibers in layers 14 and 18 can be from about 1 to about 10 pounds per ton of fiber, more specifically from about 1.5 to about 3 pounds per ton of fiber, and even more specifically, from about 2 to about 2.5 pounds per ton of fiber.

The second layer 62A can be placed inside the first layer 58A and can be formed of cellulosic material. Desirably, layer 62A has transmission properties superior to those of layer 58A to transfer the liquid to the interior. Desirably, layer 62A will be thin relative to the other layers 58A and 66A to transfer the liquid.

Desirably, the third layer 66A resides essentially in the center of the towel 50 and may include the cellulosic fibers. Desirably, the third layer 66A has higher absorption and transmission properties than the layers 58A 62A, thereby creating the transmission and d absorption gradients in the towel 50. These gradients pull the liquid the outer surfaces of the towel 50 into its interior, in where it is spread and absorbed through the layer 66A. The gradients also prevent the liquid from migrating from the interior to the surface.

The basis weight of the towel 50 can vary from about 8 grams force per square meter to about 59 grams force per square meter, desirably from about 17 grams force per square meter to about 34 grams force per square meter, and more desirably about 27 grams force per square meter. The towel 50 is made of cellulose materials that can be modified by various treatments such as, for example, thermal, mechanical and / or chemical treatments. It is contemplated that the reconstituted cellulose material may be used and / or mixed with another cellulose material. Desirably, no synthetic fibers are woven into the cellulosic material.

The strata 54A-B can be formed from pulp fibers using any suitable papermaking techniques, and one such example technique will be described hereinafter.

Figure 3 shows an example process 100 for forming a stratum 26 of the towel 10. The process 100 may include the wet supply lines 110A-E. Because the wet supply lines 110A-E can be essentially identical, only one supply line 110A will be described and detailed hereinafter.

The wet supply line 110A may include a hood 112A, a tow press 116A, and a fan pump 120A. Desirably, the hood 112A stores an aqueous suspension of cellulosic fibers, which is supplied through a stream 114A to the tow press 116 to maintain a constant pressure head. The cellulosic fibers may be bleached sulphite pulp or quimotermomechanical pulp, particularly for the outermost layers 14 and 18 of the towel 10. An outlet stream 118 of the tow press 116A may be sent to the fan pump 120A. A discharge of the fan pump 120 can then be sent to the layered headbox 125.

Then, the pump of the head box 125 can be sent to a paper forming line to form the towel , such as those described in U.S. Patent No. 5,048,589, which is incorporated herein by reference. The towel 10 can be patterned with a repellent agent to the sizing press before drying. Alternatively, the repellent agent can be added to the head boxes 110A and 110E, or sprayed onto the outer surfaces of the towel 10.

Figure 4 shows an example process 200 for forming a layer 54A of the towel 50. The process 200 can include the wet supply lines 210A-C. The wet supply lines 210A-C can be essentially identical, therefore, only the wet supply line 210A can be described in detail hereinafter.

Wet supply line 210A may include a chest 212A, a tow press 216A, and a fan pump 220A. Desirably, the hood 212A stores an aqueous suspension of cellulosic fibers, which is supplied through a stream 214A to the tow press 216A to maintain a constant pressure head. The cellulosic fibers may be sulfite pulp or bleached chemo-thermomechanical pulp, particularly for layer 58A of stratum 54A. An output stream 218A of the tow press 216A can be sent to the fan pump 220A. A discharge from the fan pump 220A can then be sent to the layered headbox 225.Then, the pump from the headbox 225 can be sent to a paper forming line to form the towel 50, such as that described in U.S. Patent Nos. 5,048,589, which is incorporated herein by reference. The towel 50 can be patterned with a repellent agent in a size press before drying. Alternatively, the repellent agent can be added to the head boxes 210A or elsewhere, such as in the supply box, or sprayed onto the outer surface of the layer 54A. Stratum 54B can be formed in essentially the same manner as described for stratum 54A. Once formed, the stratum 54B can be attached to the stratum 54A using any suitable means, such as adhesives or a strapping or binding wheel. Exemplary binding techniques are described in U.S. Patent Nos. 5,698,291, 5,622,734, and 5,543,202, which are incorporated herein by reference. If the tying wheel is desirably used only the edges of the strata 54A-B can be joined together.

Although the present invention has been described in connection with certain preferred embodiments, it should be understood that the subject matter encompassed by the present invention should not be limited to those specific embodiments. On the contrary, it is intended that the subject matter of the invention include all alternatives, modifications and equivalents as may be included within the spirit and scope of the following claims.

Claims (22)

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

1. A towel, comprising: the first and second layers having the cellulosic fibers and a repellent agent wherein the first second layers have in sandwich form essentially a third layer having cellulosic fibers with an absorbency superior to that of the first and second layers wherein all three layers they form a single stratum.

2. The towel as claimed in clause 1, characterized in that it also comprises the fourth and fifth layers placed between respectively the first and third layers and the second and third layers wherein the fourth and fifth layers have fibers, cellulosic with a transmission superior to that of the first and second layers.

3. The towel as claimed in clause 1, characterized in that the repellent agent is wax.

4. The towel as claimed in clause 1, characterized in that the repellent agent is latex.

5. The towel as claimed in clause 1, characterized in that the repellent agent is a sizing agent.

6. The towel as claimed in clause 1, characterized in that the repellent agent is silicon.

7. The towel as claimed in clause 1, characterized in that the repellent agent is printed on at least one of the first or second layers.

8. The towel as claimed in clause 1, characterized in that the repellent agent is sprayed on at least one of the first or second layers.

9. The towel as claimed in clause 1, characterized in that the repellent agent is mixed with the fibers in at least one of the first or second layers in a headbox.

10. The towel as claimed in clause 1, characterized in that at least one of the first or second layers has a pulp selected from the group consisting of sulphite pulp and bleached chemo-thermomechanical pulp, and the towel has a basis weight of around 8 grams per square meter to around 59 grams per square meter.

11. The towel as claimed in clause 2, characterized in that the third layer has an absorbency superior to that of the fourth and fifth layers.

12. The towel as claimed in clause 2, characterized in that the third layer has a transmission greater than that of the fourth and fifth layers.

13. A towel, comprising: a first layer that also includes: a first layer having cellulosic fibers d a repellent agent; a second layer having cellulosic fibers with a transmission superior to that of the first layer placed near the first layer; a third layer having cellulosic fibers with an absorbency superior to that of the first and second layers placed near the second layer; Y a second stratum joined to the first stratum being generally an identical image thereof.

14. The towel as claimed in clause 13, characterized in that the repellent agent is wax.

15. The towel as claimed in clause 13, characterized in that the repellent agent is latex.

16. The towel as claimed in clause 13, characterized in that the repellent agent is a sizing agent.

17. The towel as claimed in clause 13, characterized in that the repellent agent is silicon.

18. The towel as claimed in clause 13, characterized in that the repellent agent is impressed on the first layer of each stratum.

19. The towel as claimed in clause 13, characterized in that the repellent agent is sprayed on the first layer of each stratum.

20. The towel as claimed in clause 13, characterized in that the repellent agent is mixed with the fibers of the first layer of each layer in a headbox.

21. The towel as claimed in clause 13, characterized in that at least one of the first layers of each stratum has pulp selected from the group consisting of sulfite pulp and bleached quimotermomecánic pulp, and the towel has a basis weight from about 8 grams force per square meter to about 59 gram force per square meter.

22. The towel as claimed in clause 13, characterized in that the third layer has a transmission greater than that of the second layer. R U M N The present invention can provide a towel desirably by including the first and second layers which have the cellulosic fibers and a repellent agent. The first and second layer can essentially have a sandwich-like third layer having cellulosic fibers with an absorbency greater than that of the first and second layers. All layers can form a second layer.