Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-03-30
2004-05-11
Corcoran, Gladys J P (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S209000, C156S285000, C156S504000, C162S118000, C162S283000, C242S555300, C242S556000
Reexamination Certificate
active
06733608
ABSTRACT:
BACKGROUND OF INVENTION
1. Technical Field
The present invention relates to methods for making and processing high bulk tissue webs. More particularly, the invention pertains to a method of making a tissue web that is wound on large diameter parent rolls, unwound for finishing operations, and subsequently rewound.
2. Background
Unwinds are used widely in the paper converting industry, particularly in the production of bathroom tissue and kitchen toweling. Manufactured parent rolls are unwound for finishing operations, such as calendering, embossing, printing, ply attachment, perforating, and then rewound into retail-sized logs or rolls. At the time a parent roll runs out in a traditional operation, the spent shaft or core must be removed from the machine, and a new roll moved into position by various means such as an overhead crane or extended level rails.
INTRODUCTION TO THE INVENTION
Historically, unwinds have made use of core plugs for support on unwind stands with the power for unwinding coming from belts on the parent roll surface. Such surface driven unwind systems are not suitable for all types of tissue webs, because they can decrease the machine direction stretch, reduce the bulk, or damage the surface of some types of tissue webs, particularly high-bulk tissue webs. In contrast, center driven unwind systems have been used mainly in film unwinding.
The down time associated with a parent roll change represents a substantial reduction in total available run time. In addition, the manpower required to change a parent roll tends to negatively impact the efficiency of a rewinder line, and possibly even the productivity of neighboring operations when workers are borrowed for roll changes. Even where a finishing unit is employed to bond the expiring web and the new web together, the webs are manually threaded and advanced resulting in significant inefficiencies. Consequently, parent roll changes according to current practices can reduce the maximum output that can be obtained from a rewinder line, and may adversely impact the productivity of neighboring operations as well.
Thus, there is a need for an improved method for making and processing a web which maintains the desirable characteristics of the web, such as the bulk and uniformity of the web. There is also a need for an improved method for making and processing a web that dramatically reduces the time the machine is actually stopped, to significantly improve overall efficiency and to maintain or improve safety for all personnel.
SUMMARY OF INVENTION
One aspect of the present invention pertains to a method of making and processing a high bulk tissue web. The method comprises the steps of: depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a web; drying the web to form a dried web having a bulk of 9.0 cubic centimeters per gram or greater; winding the dried web to form a plurality of parent rolls each comprising a web wound on a core; transporting the parent rolls to an unwind stand comprising a pair of spaced apart arms, each arm comprising torque transmitting means for engaging a parent roll; engaging the torque transmitting means with a first parent roll; partially unwinding the first parent roll using variable speed drive means operably associated with the torque transmitting means; rotatably supporting the partially unwound first parent roll on a core placement table that is adapted to receive the partially unwound first parent roll from the arms; engaging the torque transmitting means with a second parent roll; bonding a leading end portion of the web on the second parent roll to a trailing end portion of the partially unwound first parent roll to form a joined web; and rewinding the joined web.
In another embodiment, a method of making and processing a high bulk, uncreped throughdried tissue web comprises the steps of: depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a web; transferring the web to a throughdrying fabric; throughdrying the web to form an uncreped throughdried web having a bulk of 6.0 cubic centimeters per gram or greater; winding the dried web to form a plurality of parent rolls each comprising an uncreped throughdried web wound on a core; transporting the parent rolls to an unwind stand comprising a pair of spaced apart arms, each arm comprising torque transmitting means for engaging a parent roll; engaging the torque transmitting means with a first parent roll; partially unwinding the first parent roll using variable speed drive means operably associated with the torque transmitting means; rotatably supporting the partially unwound first parent roll on a core placement table that is adapted to receive the partially unwound first parent roll from the arms; engaging the torque transmitting means with a second parent roll; bonding a leading end portion of the web on the second parent roll to a trailing end portion of the partially unwound first parent roll to form a joined web; and rewinding the joined web.
The unwind stand may include a frame with pivotally mounted arms. The arms desirably move the first parent roll to an unwind position for partially unwinding the first parent roll; then move the first parent roll to a position in close proximity to or contact with the core placement table; and then move the second parent roll to an unwind position for partially unwinding the second parent roll core. When the webs from the first and second parent rolls are being spliced together, the variable speed drive means and a core placement drive motor simultaneously unwind the first and second parent rolls.
The webs of the parent rolls are desirably united using a thread-up conveyor. The leading end portion of the web on the second parent roll is transported by the thread-up conveyor, which preferably comprises a vacuum means operably associated with an endless screen belt means. In one embodiment, the leading end portion of the web on the second parent roll is transported over the endless screen belt means with decreasing amounts of vacuum. Once the leading end portion of the web on the second parent roll is disposed on the trailing end portion of the web on the partially unwound first parent roll, the thread-up conveyor and unwinding of the second parent roll are operated at a same surface speed.
Advantageously, the thread-up conveyor may be moved, and in particular pivoted, relative to the second parent roll between an active position and a standby position. In the active position, the thread-up conveyor is in close proximity to or in contact with the second parent roll, whereas in the standby position the thread-up conveyor is positioned away from the parent roll.
The core placement table is desirably moveable in a direction transverse to the path of travel of the web between an inline position and a standby position. The inline position corresponds to the web centerline to enable partially unwound parent rolls to be placed on the core placement table, whereas in the standby position the core placement table is positioned away from the unwinding operation for ease of operator access.
Suitable soft, high bulk tissues for purposes of this invention include tissue sheets as described in U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to Farrington, Jr. et al. entitled “Soft Tissue”, which is herein incorporated by reference. The method is particularly useful for soft, high bulk uncreped throughdried tissue sheets. Such tissues suitably have bulk values of 6.0 cubic centimeters per gram or greater (before calendering), desirably about 9 cubic centimeters per gram or greater, more specifically from about 10 to about 35 cubic centimeters per gram, and still more specifically from about 15 to about 25 cubic centimeters per gram. The method for measuring bulk is described in the Farrington, Jr. et al. patent. In addition, the soft, high bulk tissues of this invention can be characterized by a relatively low stiffness as determined by the MD Max Slope and/or the MD Stiffness Factor, the measurement of which is also described in
Ba Dour, Jr. James B.
Baggot James Leo
Birnbaum Larry E.
Daniels Michael Earl
Fortuna Rudolph S.
Charlier Patricia A.
Corcoran Gladys J P
Glantz Douglas G.
Kimberly--Clark Worldwide, Inc.
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