Patent Application
20080023169
The preferred embodiments of the present inventions is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.
The pulp suspension is introduced into the stock entry gap 112 by the headbox 104.
The molding belt 110 is shown as an inner belt that comes into contact with the forming roll 106. The forming fabric 108 is an outer belt. The pulp suspension is delivered by the headbox 104 into the stock entry gap 112 between the two dewatering belts 108, 110. The inner belt, or molding fabric 110 coming from below is conducted over a guide roll 114 past the headbox 104 to the forming roll 106 and from there it is conducted back again over another guide roll 116.
The forming fabric 108 and molding fabric 110 converge at a convergence location 118 near the stock entry gap 112. The two fabrics 108, 110 squeeze the pulp suspension to form a paper web. The two fabrics 108, 110 separate from each other at a separating location 120 near the forming roll 106.
The yarn materials include, but are not limited to mono filament yarns, synthetic or polyester mono filament yarns, twisted mono filament yarns, twisted synthetic or twisted polyester or twisted polyamide mono filament yarns, twisted multi-filament yarns, twisted synthetic or twisted polyester multi-filament yarns, and others. Various yarn profiles can be employed, including but not limited to yarns having a circular cross sectional shape with one or more diameters, or other cross sectional shapes, for example, non-round cross sectional shapes such as oval, or a polygonal cross sectional shapes, for example diamond, square, pentagonal, hexagonal, septagonal, octagonal, and so forth, or any other shape that the yarns may be fabricated into.
Materials used to make the base fabric can be from, but not limited to, polyethylenepterathalate (PET), polyamides (PA), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT) and polyetheretherketone (PEEK). Likewise, the fabric can be made from one or more materials.
What results is a forming fabric 108 having a paper side and a wear side. On the paper side of the forming fabric 108, a polymer is applied that forms a polymeric lattice 126. The preferred polymeric material to be deposited is at least one of a silicone and a polyurethane. By way of example, the silicone can be any RTV-type two-component heat curable material. Other possible polymeric materials, selectable based on the application, include, but are not limited to, acrylics, epoxy resins, silicones, polyurethanes—such as thermoplastic, thermoset, and two component polyurethanes, hydrosols, polyolefins—such as ABS, PS, PC, PET, PPS, PEEK, PA, EVA, PE, HDPE, LDPE, LLDPE, PP, PTFE, and PVC, UV curables, rubbers—both natural and synthetic, nanopolymers/technology, carbon fullerenes, dendrimers, polymers loaded with carbon or metals, electrically conducting polymers and semi-conductors, liquid crystal polymers, hot melts, polymers that are sensitive to pressure, light and temperature, reactive polymers and living polymers.
The polymer material added to the fabric 108 can be deposited in a random pattern, a pseudo-random pattern, a predetermined pattern, or any combination of the three to form a pattern or motif on the final tissue paper. In the preferred embodiment, the polymeric material is delivered to the fabric either through a screen or from a bank of small bore tubes (needle application) set at the predetermined distance above the fabric 108.
When the screen method is used, the polymeric material is delivered through the screen by a blade that is in contact with the inside face of the screen. In this manner the polymer height L above the fabric surface 128 is determined by the thickness of the screen wall.
For the screen application, to control the flow of the polymeric material into the fabric, the viscosity of the polymeric material is less than 40,000 centipoise cP. For small bore needle applications, the viscosity of the polymeric material is less than 50,000 centipoise cP.
The viscosity of the polymeric material is selected to control the amount of penetration of the polymeric material into the fabric 108. For this invention, penetration is between about 10% and about 100%. The amount of penetration into the fabric is a function of the fabric and the use of the fabric. For general applications, the preferred penetration is approximately 40%-60%. When a fine mesh fabric is used, the preferred penetration can be up to 100%.
Height of the polymeric material L above the surface 128 of the paper side of the fabric 108 is variable depending on the method of application and the desires of the application. For example, when screening the polymeric material onto the fabric 108, the polymer material has a height L above the surface 128 of the fabric 108 of about 0.01 mm to about 1.0 mm, preferably about 0.05 mm. When used for embossing type applications, for example through air drying (TAD), the height L above the surface of the fabric is about 0.1 mm to about 2.0 mm, preferably about 0.1 mm to about 1.0 mm, most preferably about 0.05 mm. For small bore needle applications, the height L of the polymeric material can be up to 3 mm.
The polymeric lattice 126 of the preferred embodiment extends above the surface 128 of the forming fabric 108 by approximately 0.1 mm.
The polymer material added to the fabric 108 can be deposited in a random pattern, a pseudo-random pattern, a predetermined pattern, or any combination of the three to form a pattern or motif on the final tissue paper. That is, rather than a lattice as depicted, the deposition can form a pattern such as a logo, or other non-continuous pattern.
Width and length of the polymeric lattice 126 can vary, but can range from approximately 0.1 mm to approximately 2 mm, preferably 0.5 mm to 1.0 mm, and more preferably 0.7 mm to
When cured, the polymeric material has a shore A hardness of approximately 3 to approximately 80, depending on the material used and the predetermined application.
Permeability range of the fabric 108 with the applied pattern/design is approximately 50 cfm to approximately 1200 cfm, preferably in the range of approximately 200 cfm to approximately 900 cfm, and most preferably approximately 300 cfm to approximately 800 cfm.
While the present invention has been particularly shown and described with reference to the foregoing preferred embodiments, those skilled in the art will understand that many variations may be made therein without departing from the spirit and scope of the invention as defined in the following claims. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application. Where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.
