Loading patent…
AssigneeFort James Corporation
InventorsMichael S. Heath, T. Philips Oriaran, Mark S. Siegel, Frank D. Harper, John H. Dwiggins
Estimating the term…
A process for the manufacture of single-ply, absorbent paper product, printed on before or after embossing on the Yankee side, air side, or both sides, having a serpentine configuration; low sidedness; a basis weight of at least about 12.5 lbs. per 3000 square foot ream; a specific total tensile strength between 40 and 200 g/3 inches/lb per 3000 square foot ream; a cross direction specific wet tensile strength between 2.75 and 20.0 g/3 inches/lb per 3000 square foot ream; an MD tensile to CD tensile ratio between 1.25 and 2.75; a specific geometric mean tensile stiffness between 0.5 and 3.2 g/inch/% strain per pound per 3000 square foot ream; a friction deviation of less than 0.250; a sidedness parameter of less than 0.30; and a printed sidedness value of ΔE of less than 2.
A process for the manufacture of a soft, printed, single-ply bathroom tissue product having a basis weight of at least about 12.5 lbs./3000 square foot ream and having a Yankee side and an air side and having low sidedness which process comprises:
A process for the manufacture of a soft, printed, single-ply, bathroom tissue product having a basis weight of at least about 12.5 lbs./3000 square foot ream and having a Yankee side and an air side and having low sidedness which process comprises:
A process for the manufacture of a soft, printed, single-ply bathroom tissue product having a basis weight of at least about 12.5 lbs. per 3000 square foot ream and having a Yankee side and an air side and low sidedness which process comprises:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
Mechanical deformation without removing material, e.g. in combination with laminating: embossing , i.e. producing impressions formed by locally…
Reinforcing agents: wet strength agents
Characterised by function or properties in or on the paper: agents rendering paper porous, absorbent or bulky
Characteristics of the rollers: cross sectional profile of the embossments
Term end not estimated
Through air drying has become the technology of preference for making one-ply absorbent paper for many manufacturers who build new absorbent paper machines as, on balance, through air drying (“TAD”) offers many economic benefits as compared to the older technique of conventional wet-pressing (“CWP”). With through air drying, it is possible to produce a single-ply absorbent paper in the form of a tissue with good initial softness and bulk as it leaves the absorbent paper machine.
In the older wet pressing method, to produce a premium quality printed, absorbent paper, it has normally been preferred to combine two plies by embossing them together. In this way, the rougher air-side surfaces of each ply may be joined to each other and thereby concealed within the sheet. However, producing two-ply products, even on state of the art CWP machines, lowers paper machine productivity by about 20% as compared to a one-ply product. In addition, there may be a substantial cost penalty involved in the production of two-ply products because the parent rolls of each ply are not always of the same length, and a break in either of the single plies forces the operation to be shut down until it can be remedied. Also, it is not normally economic to convert older CWP tissue machines to TAD. But even though through air drying has often been preferred for new machines, conventional wet pressing is not without its advantages as well. Water may normally be removed from a cellulosic web at lower energy cost by mechanical means such as by overall compaction than by drying using hot air.
What has been needed in the art is a method of making a premium quality printed single-ply absorbent paper using conventional wet pressing having a high bulk and excellent softness attributes. In this way advantages of each technology could be combined so older CWP machines can be used to produce high quality printed single ply absorbent paper products in the form of bathroom tissue, facial tissue, and napkin at a cost which is far lower than that associated with producing two-ply absorbent paper. Two-ply absorbent papers are normally printed on the top ply. Any ink migration through the top ply (strikethrough) is hidden by the bottom ply, which also provides a barrier to further ink migration. In printing single-ply absorbent papers, it is important to prevent or minimize ink strikethrough onto process equipment, which can compromise process efficiency.
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only and thus are not limiting of the present invention.
FIG. 1 illustrates the Bear and Cupcake print pattern printed using a flexographic printing process prior to or after embossing of the one-ply absorbent paper product. One or both sides of the paper can be printed.
FIG. 2 illustrates the Bordelaise print pattern printed using a rotogravure or flexographic printing process prior to or after embossing of the one-ply absorbent paper product. One or both sides of the paper are printed.
A design can be printed either in-line or off-line of a converting process to either side of a one-ply CWP absorbent paper product in the form of a bathroom tissue, facial tissue, or a napkin exhibiting low sidedness using two conventional printing processes.
Rotogravure is an intaglio printing method offering precise ink application and transfer of a desired design image by use of a precisely etched roller surface. Design total area and color intensity can be varied by adjustment to small spaced engraved deposits (i.e., cells) in the roller surface. Design coverage can vary from 1-90% of coverage preferably 1-80% coverage. Engraving can be accomplished by chemical acid etch or electromechanical methods, with a preference for the latter method. The engraving will use a range between 100 to 200 lines per inch with engraving depths ranging between 5 to 50 microns.
Direct rotogravure is the preferred gravure method of choice, as shown in FIGS. 10A and 10B, but offset gravure, illustrated in FIGS. 12A and 12B, are also suitable methods. The design image is transferred to the one-ply CWP substrate when the web (FIG. 10A, Number 70) is passed in contact between the engraved roller (61) and a covered impression roller (64). This impression roller (64) covering can be a natural or synthetic rubber with a durometer between 60 and 90 Shore A. Contact between the rollers will range from 0.250 to 0.625 inches. Ink is recirculated from a supply source (63) to an applicator head (62) which is in contact with the engraved roller (61). Solvent or waterbased inks are suitably used with a preference for waterbased inks at dilution ratios ranging between 10 to 20 parts water to 1 part concentrated ink.