Patent Application
20170282489
Modern paper-making techniques use paper machines at paper mills to produce rolls of paper that, in turn, can be used by board makers to produce board products (i.e., corrugated board). As a result, rolls of paper may be produced from machines that operate continuously. Modern paper machines typically produce paper from a number of substances including wood pulp that comprise wood fibers (although other fibers may also be used). These fibers tend to be elongated and suitable to be aligned next to one another. The fiber starts as a slurry that can be fed onto a moving screen from a head box of the paper machine. In modern paper machines, the fibers tend to align with each other and align with a direction in which the screen is moving. This alignment direction of underlying fibers is called the major direction of the paper and is in line with the machine direction. Thus, the major direction is often simply called the machine direction (MD) and the paper that is produced has an associated MD value.
When paper is used to make a board product, portions or layers of the board product may be corrugated. Traditional corrugating machines will corrugate the underlying paper product in the cross direction (CD) of the paper thereby failing to take advantage of the natural strength bias of the paper in the machine direction. Further, the greater natural strength qualities of paper in the machine direction are left unharnessed by cross corrugation techniques in board making solutions. As a result, companies that produce conventional board products remain entrenched in old production processes that limit the strength of the board product.
Aspects and many of the attendant advantages of the claims will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The following discussion is presented to enable a person skilled in the art to make and use the subject matter disclosed herein. The general principles described herein may be applied to embodiments and applications other than those detailed above without departing from the spirit and scope of the present detailed description. The present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed or suggested herein.
By way of overview, the subject matter disclosed herein may be directed to a system and method for producing a board product made from paper products that have at least one corrugated medium (sometimes called corrugated fluting) and at least one embossed medium (sometimes called embossed fluting). The board product may further include one or more facings (sometimes called liners or walls) that are adhesively coupled to the corrugated medium, the embossed medium, or both. Generally speaking, a corrugated medium may be characterized as a paper product that exhibits flutes induced by a corrugating process such that the induced flutes are perpendicular (or at least not congruent) with the machine direction of the paper product. That is, the corrugated medium has flutes in the cross direction of the paper. An embossed medium may be characterized as a paper product that exhibits flutes induced by an embossing process such that the induced flutes are aligned with the machine direction of the paper product.
When a board product is produced such that a corrugated medium and an embossed medium are adhesively coupled and flanked by a facing on either outside surface, the resultant characteristics of the board product is superior to conventional board product that use only corrugated medium. This is because the embossed medium is produced using a linear embossing process that takes advantage of the natural strength of the machine direction of the paper product. Additional permutations of the underlying concept of having a cross-corrugated medium and a linearly embossed medium in the same board product are possible, including disposing a facing between the corrugated medium and the embossed medium and having facings on one or both outer walls of the board product. These advantages and additional aspects of various embodiments of the subject matter disclosed herein are discussed below with respect to
Prior to discussing the various embodiments, a brief discussion about cross corrugating and linear embossing is presented. As has been briefly stated above, conventional board products include a conventionally produced corrugated medium, e.g., a cross-corrugated medium. A cross-corrugated medium has flutes formed perpendicular to most underlying fibers of the paper product. This results in flutes that are not aligned with the majority of underlying fibers and, therefore, do not take advantage of the natural strength of the MD value of the paper (when compared to the CD value). Such a failure to harness the MD value of the paper leads to loss of opportunity in the manufacturing of board products when specific board strength is to be realized. That is, it will necessarily take more paper (heavier paper, larger flutes, and the like) to realize the required board strength.
A linearly-embossed medium is different from a cross-corrugated medium in that the induced flutes are aligned with the MD value of the paper product. This results in flutes that are aligned with the majority of underlying fibers and, therefore, take full advantage of the natural strength of the MD value of the paper (when compared to the CD value). Harnessing the MD value of the paper leads to efficiencies in the manufacturing of board products when specific board strength is to be realized. That is, it will necessarily take less paper (lighter paper, smaller flutes, and the like) to realize the required board strength. Aspects of making, producing, and using linearly embossed mediums are discussed in greater detail in U.S. patent application Ser. No. 15/077,250 entitled “SYSTEM AND METHOD FOR INDUCING FLUTING IN A PAPER PRODUCT BY EMBOSSING WITH RESPECT TO MACHINE DIRECTION” and filed on Mar. 22, 2016, which is incorporated herein by reference in its entirety and for all purposes. Thus, the aspects of linearly-embossed mediums will not be discussed further for brevity as the discussion now turns to
Notwithstanding its failure to harness the natural strength of the paper in the machine direction 122, the cross-corrugated medium 120 of
Likewise, a second facing 140 may form a bottom-side outer wall (again, the top/bottom direction reference is arbitrary) that is coupled to one side of the embossed medium 130. The coupling may be through an adhesive applied to the apex of each flute on the bottom-side of the embossed medium 130 such that the facing 140 is glued to the embossed medium 140 where adhesive is applied. In other embodiments, glue may be applied to the entirety of the facing 140 prior to being coupled to the embossed medium 130.
Further, the corrugated medium 120 and the embossed medium 130 may also be glued to each other using adhesive. Because the flutes of the corrugated medium 120 are aligned in the cross direction and the flutes of the embossed medium 130 are aligned in the machine direction, the contact points between these two mediums will be at the crossings of the apexes of the respective flutes. In this manner, the corrugated medium 120 and the embossed medium 130 are affixed with respect to one another because of the adhesive holding one medium directly to the other.
When all four layers are assembled and affixed, the resultant board product 100 is stronger than conventional board product because the linearly embossed medium 130 takes advantage of the superior MD value of the underlying paper product. As can also be seen in
In the embodiment shown in
In yet other embodiments (also not shown), the flutes of the corrugated medium 120 and the embossed medium 130 may be aligned with each other when assembled. The corrugated medium 120 will still have the corrugated flutes induced in the cross direction of the paper and the embossed medium 130 will still have flutes induced in the machine direction of the paper. But, one of the two mediums may be transferred 90 degrees during a board assembling process in an effort to align the flutes of the two mediums 120 and 130 while still taking advantage of a linearly embossed medium 130 that harnesses the MD value of paper.
In another embodiment not shown, a board product 100 may include four layers as shown in the board product of
As has been discussed with respect to
Such a board product having a linearly-embossed medium 130 further leads to efficiencies on several levels and succeeds in realigning the interests of paper makers and board/box makers. First, linear embossing allows the paper maker to disregard any need to carefully control the alignment (or rather non-alignment) of the pulp fibers when first poured onto a screen on a paper machine. Paper makers, in order to improve strength in the cross direction, may employ paper machines that include a head box that combats the natural alignment of underlying long fibers in the machine direction. With linear embossing, the need for improved strength in the cross direction is reduced or eliminated. Therefore, the paper-maker can focus on improving the speed of the paper machine.
Second, board makers can produce board products with less paper material. The linearly embossed layer 130 discussed herein lead to a fluted medium that requires less material for production. That is, in conventional corrugating machines, the paper needed for the fluted medium is greater than the paper needed for a facing portion (in linear terms). Thus, the efficiency gain is two-fold: less overall paper used in making corrugated board and greater strength in the resultant board by aligning the MD value in both flutes and facings.
The embodiments as discussed with respect to
The paper from each roll may be unwound from each respective roll and fed toward a combiner 450 that is configured to combine the various layers of paper together to form a resultant board product. In various embodiments, the combination of feed rolls in the machine 400 may be different from what is shown in
Prior to entering the combiner 450, at least some of the paper from the feed rolls may be passed through a stage for forming the paper into a medium. As used herein and in the industry, a medium may refer to a paper product that has been formed into paper having flutes. Thus, the corrugated medium feed roll 420 may feed paper into first and second corrugating rolls 421a and 421b that are aligned with respect to each other. As the paper exits the corrugating stage (e.g., corrugating rolls 421a and 421b), it becomes the corrugated medium 120 as discussed above with respect to
In the embodiment that produces the board product of
Other machine 400 embodiments may be configured to produce different board products with differing arrangements of paper, facing, and medium. For example, another facing feed roll 445 may be included to feed a third facing 446 to be disposed between the cross-corrugated medium 120 and the linearly-embossed medium 130. Thus, five layers may be fed to the combiner 450 to produce a board product having five layers assembled together. Such a board product is discussed next with respect to
Further, the corrugated medium 120 and the embossed medium 130 may also be glued to a middle facing 446 using adhesive. In this manner, the corrugated medium 120 and the embossed medium 130 are affixed with respect to one another because of the adhesive holding each medium to the middle facing 446. When all five layers are assembled and affixed, the resultant board product 500 is stronger than conventional board product because the linearly-embossed medium 130 takes advantage of the superior MD value of the underlying paper product. As can also be seen in
While the subject matter discussed herein is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the claims to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the claims.
