Patent Application
20110111940
The present invention is related to conversion of a sheet stock material into a relatively lower density dunnage product, and more particularly to a method of converting a paper into a relatively less dense dunnage product, and an exemplary paper for conversion.
Dunnage conversion machines convert a stock material into a dunnage product that can be used to pack articles and thus minimize or prevent damage during shipment. The dunnage conversion machines, also referred to as dunnage converters, include a conversion mechanism that converts a stock material into a relatively lower density dunnage product as the stock material moves through the conversion mechanism from an upstream end toward an outlet at a downstream end.
Paper is a sheet stock material that can be converted into a relatively lower density and relatively thicker dunnage product. Paper thickness is commonly measured in terms of “caliper.” The caliper of the paper is measured in fractions of a millimeter or inch by placing a single sheet under a steady pressure between parallel surfaces. Paper thickness can vary, however, so caliper also can be determined using a “bulk caliper” measurement. A bulk caliper measurement is taken of ten layers, for example, and the result is divided by ten to arrive at an average thickness. A typical thirty-pound basis weight (about 81 grams per square meter) kraft paper has a bulk caliper of about 0.0031 inch (about 0.079 millimeter). The thousandths-of-an-inch caliper measurement is sometimes referred to as “points,” so that in the above example the bulk caliper could be referred to as 3.1 thousandths of an inch or 3.1 points.
Paper typically has a moisture content of approximately 7%. Paper can change thickness if it absorbs additional moisture. The caliper measurements in the above example were taken at a moisture content of no more than 10%.
Toward the end of the paper-making process, the paper is fed through a series of polished rollers to produce a relatively smoother surface on the paper and to produce a paper with a more uniform thickness. This process is referred to as “calendaring.” Calendaring also tends to reduce the average thickness of the paper.
The present invention provides an improved method for producing a dunnage product by converting a flash-dried paper into a relatively thicker and less dense, dunnage product.
An exemplary method of converting a sheet stock material into a relatively less dense dunnage product includes the step of supplying the sheet stock material to a conversion mechanism for converting the sheet stock material into the dunnage product by permanently deforming the sheet stock material into a nonplanar configuration to provide the dunnage product with a density less than the density of the stock material from which it is formed. The sheet stock material comprises one or more plies of paper having a caliper no less than about 3.5 points or a bulk caliper no less than about 3.4 points (0.086 millimeter) for a basis weight no greater than about 32 pounds (about 86 grams per square meter) and when a moisture content is no greater than about 10%.
An exemplary sheet stock material comprises a plurality of superimposed plies of kraft paper, at least two plies having a caliper no less than 3.5 points or a bulk caliper no less than 4.0 points for a basis weight no greater than 32 pounds and when a moisture content is no greater than 10%. The sheet stock material preferably includes at least one ply of a non-calendared paper.
An exemplary sheet stock material for use with a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of kraft paper having a caliper no less than about 3.5 points or a bulk caliper no less than about 4.0 points for a basis weight no greater than 32 pounds and when a moisture content is no greater than about 10%.
Another exemplary sheet stock material for use with a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of kraft paper that was subjected to a flash drying process when it was made.
Finally, an exemplary sheet stock material for use in a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of a puffed paper provided by Bear Lake Fibre, LLC of Niles, Mich., U.S.
The foregoing and other features of the invention are hereinafter fully described and particularly pointed out in the claims, the following description and annexed drawings setting forth in detail certain illustrative embodiments of the invention, these embodiments being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
The present invention provides a method of converting paper into a relatively thicker and less dense dunnage product. An exemplary paper is a yield-enhanced, flash-dried paper having a relatively thicker caliper and/or bulk caliper, a basis weight no greater than about 32 pounds (about 86 grams per square meter), and a moisture content of no greater than about 10% for conversion into a relatively less dense dunnage product.
Referring now to the drawings in detail, and initially to
The sheet stock material typically is provided in the form of a continuous length wound to form a roll 120 or fan-folded in a stack 122 shown in
In a roll of stock material, the stock material can be drawn from the outer surface of the roll, typically allowing the roll to rotate or turn as the stock material is drawn therefrom. Alternatively, the stock material can be drawn from the center of the roll.
The stock material provided by the present invention is paper, and particularly a flash-dried paper produced by Bear Lake Fibre, LLC of Niles, Mich., U.S. Flash drying typically occurs in a pre-drying stage of the paper-making process by rapidly heating a fiber slurry to remove the water. The rapid heating causes a violent expansion of the paper fibers that creates a puffed or fluffed web of paper that can be rolled or fan-folded for storage and shipment before being converted to a dunnage product. The paper preferably is not calendared, so that the paper is relatively thicker, has a less uniform thickness, and a rougher surface texture than a calendared paper.
The stock material may include different weights or thicknesses or combinations thereof, but generally the paper has a caliper of no less than 3.5 points (0.089 millimeter) or a bulk caliper of no less than 3.4 points (0.086 millimeter) for a basis weight no greater than 32 pounds (about 86 grams per square meter) and when a moisture content in the paper is no greater than about 10%. The paper has a basis weight of about 20 pounds (about 54 grams per square meter) to about 30 pounds (about 81 grams per square meter), and more particularly a basis weight of about 23 pounds (about 62 grams per square meter) to about 26 pounds (about 70 grams per square meter). The paper preferably includes 100% recycled paper fibers. This paper also is more porous and generally stronger than typical relatively-lower caliper kraft paper. Consequently, the dunnage product produced by the conversion process employing this paper also is expected to have a lower weight but greater strength compared to dunnage products produced by other types of stock material.
We compared a typical thirty-pound (about 81 grams per square meter) kraft paper, with a caliper of about 3.4 points (about 0.086 mm) and a bulk caliper of about 3.1 points (about 0.079 mm), to a relatively higher caliper kraft paper provided for conversion in the present invention. The high caliper kraft paper had a caliper of about 4.2 points (about 0.107 mm) and a bulk caliper of about 3.6 points (about 0.912 mm). The high caliper kraft paper provided a 23% increase in caliper and a 16% increase in bulk caliper. Other test results for comparing a relatively low caliper paper sample and a relatively high caliper paper sample are summarized in the following table.
This relatively high caliper paper also provides a higher yield when converted to dunnage. In one instance the high caliper paper provided an approximately 33% increase in yield. Yield in the dunnage conversion context means that a greater amount of dunnage is produced for a given amount of stock material consumed in the process. The amounts can be measured as length and/or volume.
Many different types of conversion mechanism 110 (
The dunnage conversion machine 230 shown in
Another dunnage conversion machine 240 is shown in
Still another type of conversion machine 250 is shown in
Other types of conversion mechanisms or other means for converting the sheet stock material into a relatively thicker and/or less dense dunnage product can be used in place of the illustrated conversion machines 230, 240, and 250. For further details about dunnage conversion machines as shown or similar to the ones shown in
An exemplary method of converting a sheet stock material into a relatively less dense dunnage product includes the step of supplying the sheet stock material to a conversion mechanism for converting the sheet stock material into the dunnage product by permanently deforming the sheet stock material into a nonplanar configuration to provide the dunnage product with a density less than the density of the stock material from which it is formed. The sheet stock material comprises one or more plies of paper having a caliper no less than about 3.5 points (about 0.089 millimeter) or a bulk caliper no less than about 3.4 points (about 0.086 millimeter) for a basis weight no greater than about 32 pounds (about 86 grams per square meter) and when a moisture content is no greater than about 10%.
An exemplary sheet stock material comprises a plurality of superimposed plies of kraft paper, at least two plies having a caliper no less than 3.5 points or a bulk caliper no less than 4.0 points for a basis weight no greater than 32 pounds and when a moisture content is no greater than 10%. The sheet stock material preferably includes at least one ply of a non-calendared paper.
An exemplary sheet stock material for use with a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of kraft paper having a caliper no less than about 3.5 points or a bulk caliper no less than about 4.0 points for a basis weight no greater than 32 pounds and when a moisture content is no greater than about 10%.
Another exemplary sheet stock material for use with a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of kraft paper that was subjected to a flash drying process when it was made.
Finally, an exemplary sheet stock material for use in a conversion machine that converts the sheet stock material into a dunnage product includes a plurality of superimposed plies of a puffed paper provided by Bear Lake Fibre, LLC of Niles, Mich., U.S.
Although the invention has been shown and described with respect to a certain illustrated embodiment or embodiments, equivalent alterations and modifications will occur to others skilled in the art upon reading and understanding the specification and the annexed drawings. In particular regard to the various functions performed by the above described integers (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such integers are intended to correspond, unless otherwise indicated, to any integer which performs the specified function (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated embodiment or embodiments of the invention.
This application claims the benefit of U.S. Provisional Patent Application No. 61/079,408, filed Jul. 9, 2008, which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2009/050097 | 7/9/2009 | WO | 00 | 1/7/2011 |
| Number | Date | Country | |
|---|---|---|---|
| 61079408 | Jul 2008 | US |
