Method for manufacturing an adhesive compound for use in the production of corrugated paperboard

A method of manufacturing an adhesive composition for use in the production of paperboard is provided. An amount of water contained within a source container is provided. The water is heated to a first temperature. A rheology modifier is added to the heated water to create a heated solution. A starch is added to the heated solution. The heated solution is mixed for a first period of time to create a heated mixture. Additionally, there may be more independent time segments determining an amount of time which the components of the heated solution are mixed or blended together. Additional elements of the adhesive composition are added to the heated mixture between each mixing time segment.

BACKGROUND OF THE INVENTION

Technical Field

The present invention relates generally to adhesive used in the manufacture of corrugated paperboard. More particularly, the present invention relates to the method of manufacturing the adhesive used in the fabrication of corrugated paperboard. Specifically, the present invention provides a method of mixing a set of mixtures and solutions in a series of distinct and non-continuous time segments to create an adhesive composition for use in attaching at least one liner material to a corrugated medium material.

Background Information

Corrugated paperboard is produced when a sheet of medium material, usually a strong paper made largely of bleached or unbleached sulfate pulp, is corrugated by passing through a corrugating machine. Upon leaving the corrugating machine, the corrugated medium material has a series of flutes formed in a sinusoidal shape when viewed from the side. Adhesive is applied to the crests or apexes of the flutes by a glue applicator roll. Then, a first liner is attached to the corrugated medium atop the adhesive. Thereafter, a second adhesive applicator applies additional adhesive to the flutes spaced opposite the first set of flutes. Then, a second liner is connected to the second set of flutes to create a double-faced sheet of paperboard.

In most corrugating operations, the corrugating rolls used to corrugate and shape the medium material are at a temperature of approximately 300° F. This heat transfers to the medium material as it extends through the corrugating machine which helps cure the adhesive. The adhesive most often used in paperboard manufacture is often a starch-based adhesive that requires heat and pressure as part of the chemical reaction to gelatinize the starch into a film. Then water must be removed from the adhesive, often by the application of more heat, in order to fully cure the adhesive.

One problem that occurs is that most methods of available to heat paper to its desired temperature for bonding on the corrugator simultaneously remove water as the paper is being heated. One way to combat the resulting water removal is to use an infusion or pre-wetting system such as one that tries to inject steam under the web through the surface of the heating device to reduce this moisture loss. This device is very speed dependent and difficult to control. Additionally, since the typical corrugator continually changes speeds in a matter of seconds, and the current methods of heating paper sometimes respond in minutes, it becomes difficult to achieve specific temperature and moisture content independently of one another.

The flatness or dimensional stability of a finished paperboard product is often dependent on the moisture balance between the two outside liners that are bonded to the inner corrugated medium paper web. After the three pieces are combined into a sheet of paperboard, the individual sheets of paper often lose or gain moisture to or from one another and the surrounding atmosphere until an equilibrium condition is reached. In order to achieve optimum flatness, the individual sheets of paper should gain or lose as little moisture as possible during the process and should be as close to their equilibrium moisture as possible upon exiting the corrugating machine. This way, post-warp may be minimized.

Many manufacturers of paperboard have improvised types of improvements and have gained patents on new and unique ways to prevent paperboard warping during manufacture. Namely, U.S. Pat. No. 8,398,802 issued to Kohler discloses a method of adjusting the moisture content in a traveling web of medium material so that the web of medium material comprises a 6-9% weight percentage by moisture prior to corrugating. Then that web of medium material is heated to nearly 100° C. Then the material is corrugated such that the web of medium material retains the 6-9% weight percentage moisture through the corrugating steps. Kohler discloses that this method reduces warping and prevents an evenly applied cured adhesive.

Further, additional suppliers have sought patent protection on improved adhesive formulas. Name, PCT Application WO 2011/160049 assigned to Cargill Incorporated discloses an improved adhesive composition that contains a reduced amount of solids. The adhesive composition of the '049 Application includes the following components: a starch, a borate, an alkaline hydroxide, and a rheology modifier. To make the adhesive composition, the '049 Application requires that the components are all added together at one time into an amount of heated water in the range of 50° C.-59° C. (122° F.-138.2° F.), the solution is quenched with water, then reheated to a temperature in the range of 32° C.-44° C. (89.6° F.-111.2° F.), then the solution is mixed continuously for eight minutes to create an adhesive composition. The '049 Application further discloses using nearly 50% less adhesive than ordinarily used in a paperboard manufacturing process. However, in order to do so, the '049 Application requires that the liner temperatures are controlled and constrained in a range of 70-90° C.

From an academic standpoint, the '049 Application reduces the amount of solids within the adhesive in the paperboard manufacturing process. However, it is has been realized that real world applications do not often yield expected results and raise additional issues propagating manufacturing concerns that must be addressed. The present invention addresses these and other issues to cure the concerns.

SUMMARY

In accordance with one embodiment, the present invention may provide a method of manufacturing an adhesive compound, the method comprising the steps of: providing an amount of water contained within a source container; heating the water to a first temperature; adding a rheology modifier to the heated water to create a heated solution; adding a starch to the heated solution; mixing the heated solution for a first period of time to create a heated mixture.

Another embodiment of the present invention may provide a method of manufacturing an adhesive composition for use in the production of paperboard is provided. An amount of water contained within a source container is provided. Then, the water is heated to a first temperature. Next, a rheology modifier is added to the heated water to create a heated solution. Then, a starch is added to the heated solution. Then, the heated solution is mixed for a first period of time to create a heated mixture. Additionally, there are four more independent time segments determining an amount of time which the components of the heated solution are mixed or blended together. Additional elements of the adhesive composition are added to the heated mixture between each mixing time segment.

Yet another embodiment of the present invention provides an adhesive compound comprising: a starch, a biocide, a defoamer; and a penetrating agent. The biocide is from about 0.05 to about 0.15% solids by weight (% wt. solids) of the adhesive compound. The defoamer mass is about 6% of the mass of the biocide. The penetrating agent mass is about 35% of the mass of the biocide.

DETAILED DESCRIPTION

As known in the Prior Art and shown inFIG. 1(PRIOR ART), a prior art sheet10of manufactured paperboard includes a corrugated medium material12juxtaposed between a first or top liner14and a second or bottom liner16. During manufacture of prior art paperboard10, the two outside liners14,16are bonded to arcuate flutes defining the sinusoidally shaped corrugated paper web material12. After combination into laminate sheets of paperboard10, the individual sheets,12,14, and16, lose or gain moisture to or from each other and the surrounding atmosphere until an equilibrium condition is reached. Warping occurs when the respective sheets12,14,16lose moisture at different evaporation rates. This causes paperboard10to warp or bow in a manner that reduces the flatness of paperboard10. As shown in the prior artFIG. 1, when evaporation rates between the three liners are not equal, paperboard10can bow upwards forming a concave surface when viewed from the side. Warping is an undesirable result of the paperboard10manufacturing process.

As known in the Prior Art and shown inFIG. 2(PRIOR ART), the prior art paperboard10may also have delamination problems caused by unbonded adhesive. Delamination occurs when adhesive is either non-evenly applied to the flutes of the corrugated sheet14, or when the adhesive does not cure properly. The delamination leaves streaks across paperboard10. The streaks represent sections of paperboard10that either liner14or liner16is unbonded to corrugated medium12. The non-bonded portions greatly reduce the strength and structural rigidity of paperboard10. Delamination is an undesirable result of the paperboard10manufacturing process.

The problems often arising in the prior art, as shown inFIGS. 1 and 2, are reduced by the present invention detailed inFIGS. 3-10. In accordance with an aspect of the present invention shown inFIGS. 3-10, the present invention shown generally as1000(FIG. 3) provides a system and a method for moisture and temperature control in the corrugation of paperboard that reduces warping and delamination problems ordinarily associated with the prior art. In accordance with another aspect of the present invention1000, system provides a method of manufacturing paperboard having the desirable result of being planar or flat with an evenly cured and strong adhesive.

As shown inFIG. 3, a block diagram of an exemplary corrugating apparatus and system1000of the present invention is shown schematically. System1000includes a medium material conditioning apparatus100, a web heating arrangement200, a single facer300, a glue machine400, and a double backer500. The components are arranged in the recited order relative to one corrugating machine direction of a web of medium material50as it travels or Flows (Flow represented by Arrow “F”) along a sheet material pathway, wherein the sheet material pathway is defined by the components100,200,300,400, and500of system1000in order to produce a finished corrugated product60upon exiting double backer500as schematically illustrated inFIG. 3. The medium material50will become the corrugated web to which a first liner52and a second liner54will be adhered on opposite sides to produce the finished corrugated paperboard60.

As shown inFIG. 4, conditioning apparatus100comprises a pre-tension apparatus110including a first roll110a, second roll110band third roll110c. The three rolls110a,110b,110care each cylindrical having two ends with a substantially uniform cylindrical sidewall extending therebetween. Rolls110a,110b,110care connected to a frame58and extend laterally approximately perpendicular to flow F direction flowing along the sheet material pathway. Rolls110a,110b,110care longitudinally adjustable (in the upstream or downstream direction, when viewed from the side;FIG. 4) to control a desired about of tension in material50as it flows along the sheet material pathway.

First roll110arotates about an axis substantially perpendicular to the downstream direction of flowing material50as indicated by Arrow(s) F. Preferably, first roll110ais positioned vertically above third roll110c. When viewed from the side (FIG. 4), second roll110bis positioned longitudinally upstream from rolls110aand110c, and second roll110bis positioned vertically between first roll110aand third roll110c. The material pathway extends over the outer surface of each roll110a,110b,110c, thus as material50is fed along the pathway, material50forms a U-shape (when viewed from the side). Each roll110a,110b, and110cof pre-tension apparatus110respectively keep material50flowing along the sheet material pathway at a desired tension and speed.

Conditioning apparatus100further includes a moisture application roller120. Roller120defines a portion of the sheet material pathway. Moisture applicator roll120is configured to increase the amount of moisture percentage by weight (% wt.) within the sheet of material flowing through conditioning apparatus100. Moisture application roller120includes two ends connected to the frame58having a cylindrical sidewall extending therebetween. Ends may be connected to the frame58via bearing or other conventionally known devices to permit rotation. The cylindrical sidewall of moisture application roller is constructed of a material to attract liquid (in this example water). The outer surface of cylindrical sidewall of roller120holds water via surface tension forces as roller120rotates about an axis. The rotational movement of roller120creates a tangential velocity120vand an angular velocity. Clearly, the tangential velocity120vtand the angular velocity are dependent on radius of cylindrical roller120. The formulaic relationship is ν=rω; where v=the tangential velocity120vtof outer surface of roller120, r=the radius of roller120measured from the center to the outer surface, and ω=the angular velocity of roller120.

Roller120rotates in the direction of Arrow A (FIG. 4). The rotation causes outer surface of roller120to move in a direction opposite the direction of material50flowing (in the direction of Arrow(s) F) along the sheet material pathway at a surface tangential velocity120vt. The tangential velocity120vtof outer surface of moisture application of roller120depends on and is a percentage of the linear speed50vof material50moving F along the sheet material pathway.

Roller120contacts one side of medium material50and applies moisture to the side of 50 in contact with the surface of roller120. While the shown embodiment discloses one moisture application roller120, clearly a second moisture application roller positioned on the opposite side of sheet50from first roller120is possible to dually pre-wet sheet50from each side.

A moisture metering device130is positioned closely adjacent the outer surface of applicator roller120to apply a thin film of liquid or moisture132(FIG. 4B) to outer surface of roller120. The thin film of liquid132can include any or all of water, adhesives, additives, and/or other liquids which may have various solids or gases contained therein. For clarity, the following examples used throughout herein will be described with reference to liquid being water though it is entirely possible that other fluid combinations may be used. Metering device130includes a rod assembly134containing an elongated cylindrical shaft136wrapped or circumscribed by threads138. Rod136is positioned along an axis parallel to axis of applicator roller120. In some embodiments rod136may be fixed and in another embodiment rod136may rotate about its axis. In the rotatable embodiment, each end of rod136may be connected to device130via a plurality of bearings to allow rod136to rotate about its axis. Additionally rod136may connect to the frame for securing rod adjacent roller120. Metering device130may further include a liquid storage chamber or liquid source140in fluid communication with grooves142. Grooves142are defined by the convex outer surface of threads138. Groove142, when viewed in cross-section (FIG. 4B), forms continuous but non-linear voids for carrying and transferring water to surface of applicator roll120. Additionally, other conventionally known metering rod devices comprising elements such as various channels or fluid pressure members to drive water or fluid towards channel142are clearly impossible. When such bladder driven fluid pressure devices are used, pressure may be continuous and uniform along the entire length of the metering rod, or clearly it may be semi-continuous and non-uniform if preferred for a certain application.

Rod136is connected to the frame58such that rod136does not deflect up nor down as a result of the hydrostatic pressure with respect to rotating roller120. Rod136remains substantially parallel and in the same plane during operation. Therefore, rod136produces a uniform thickness or coating of liquid on outer circumferential surface of roller120moving at tangential velocity v in the direction of Arrow A.

The sheet of medium material50flows F along the sheet material pathway at a linear velocity50v. There are a series of speed threshold ranges, wherein the linear velocity of the flowing F medium material50is within one of the threshold ranges, the ranges defining a numerical boundary for the percentage amount of the tangential velocity120vtof the applicator roll120, thereby determining the amount metered liquid applied to the applicator roll120and thus available to be transferred to material50. The speed threshold ranges form a stepwise graph function such that the tangential velocity120vtof the applicator roll120is the same percentage of the material linear velocity for the any linear material velocity within a respective step of the stepwise graph function. The amount of liquid metered onto the applicator roll120depends on the angular velocity of the applicator roll120and the tangential velocity120vtof the applicator roll120is a percentage of the linear velocity50vof the flowing sheet of medium material50within a speed threshold range. Linear velocity50vis preferably measured downstream from double backer500(FIG. 3) by a speed measuring device mounted adjacent the material pathway. However, it is clearly contemplated that the speed measuring device may be mounted in other locations for measuring line speed50vto determine tangential velocity120vtof the applicator roll120.

The speed threshold ranges of the linear velocity50vof material50flowing F along the sheet material pathway include a first range from about 1 foot per minute (FPM) to about 150 FPM; a second range from about 150 FPM to about 350 FPM; a third range from about 350 FPM to about 650 FPM; a fourth range from about 650 FPM to about 1000 FPM; a fifth range from about 1000 FPM to about 20,000 FPM. When system1000is operational the linear velocity50vof the flowing F medium material50is within one of the first, second, third, fourth, and fifth ranges.

By way of non-limiting example, if a metering rod136is a size 6 metering rod as one would understand in the art, then when the linear velocity50vof the flowing material50is within the first range, the tangential velocity120vtof the applicator roll120is about 40% to about 30% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material50is within the second range, the tangential velocity120vtof the applicator roll120is about 30% to about 20% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material50is within the third range, the tangential velocity120vtof the applicator roll120is about 20% to about 7% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material is within the fourth range, the tangential velocity120vtof the applicator roll120is about 7% to about 4% of the linear velocity50vof the flowing medium material50. And, when the linear velocity50vof the flowing F material50is within the fifth range, the tangential velocity120v1of the applicator roll120is about 4% to about 2% of the linear velocity50vof the flowing medium material50.

By way of an additional non-limiting example, if metering rod136is a size 10 as one in the art would understand, then when the linear velocity50vof the flowing material50is within the first range, the tangential velocity120vtof the applicator roll120is about 120% to about 30% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material50is within the second range, the tangential velocity120vtof the applicator roll120is about 110% to about 15% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material is within the third range, the tangential velocity120vtof the applicator roll120is about 100% to about 7% of the linear velocity50vof the flowing medium material50. When the linear velocity50vof the flowing material is within the fourth range, the tangential velocity120vtof the applicator roll120rotates is about 95% to about 4% of the linear velocity50vof the flowing medium material50. And, when the linear velocity50vof the flowing material is within the fifth range, the tangential velocity120vtof the applicator roll120is about 70% to about 2% of the linear velocity50vof the flowing medium material50.

With primary reference toFIG. 5, a web heating arrangement200includes a plurality of idle rollers202,204,206,208,210each connected to the frame58and rotating about a respective axis all of which extend laterally and substantially perpendicular to the flow direction F of sheet material50along the pathway. Heating arrangement200further includes heating roll212operatively connected to a heat source214, a first drive roller216and a second drive roller218. Heat source214is contemplated being a compressed steam system as conventionally understood in the art. The compressed steam (“steam” refers to water is its gaseous state) in heat source214increases in temperature as more pressure is imparted into the steam. Steam produced from source214is in communication with heat roll212and preferably contained therein. The steam contained in roll212imparts a temperature to the outer surface of the roll212through conductive, radiant, or convective heat transfer. Clearly, additional types of heating device used to heat rollers in similar paperboard manufacturing processes may be substituted for the compressed steam system heating.

Steam temperature pressure tables are well known in the art. Pressurized or compressed steam tables indicate the gauge pressure of steam, in pounds per square inch (psi), and the corresponding temperature of the saturated steam. An exemplary Steam Temperature Pressure Table is provided below in Table 1:

Each of the rolls202,204,206,208,210,212,214,216, and218respectively define a portion of the sheet material pathway along which material50flows F downstream from the pre-wetting apparatus100towards the corrugator300. Heating arrangement200further includes a moisture control system280electronically connected to one or more moisture measurement devices282,284. Control system280is configured to provide a closed loop control of moisture measuring system in the web50flowing downstream. The moisture measurement device280can measure moisture in the paper web50before and after paper is heated by roll212of heating arrangement200. Control system280may contain computer logic software or other integrated software to operate free from human monitoring.

Rollers202and204are preferably positioned above heat roller212. When viewed from the side (as inFIG. 5), material50forms a U-shape pathway between rollers202,204and heat roller212. Idle rollers206and208are positioned downstream from heat roller212. Rollers206and208are positioned above drive roller216and form a second U-shaped pathway therewith. Second drive roller218and idle roller210are positioned downstream from idle roller208and form a third U-shaped pathway therewith.

Preferably, and with continued reference to heating apparatus200, when the medium material50(FIG. 5) flows F through heating device200, material50is preferably heated via contact with heat roll212to a temperature in a range from 150 degrees Fahrenheit to 170 degrees Fahrenheit. When first liner52traverses through heating device200(FIG. 6; liner52flowing “FROM200”), liner52is heated via a heat roll, same as212, to a temperature in a range from about 185 degrees Fahrenheit to about 205 degrees Fahrenheit. Providing medium50at a lower temperature than liner52provides unexpected results that reduce warping and produce a flatter paperboard60. Further, second liner54(FIG. 8; second liner54flowing “FROM200”) is heated, via a heat roll same as212, to a temperature up to but not exceeding about 130 degrees Fahrenheit, and is preferably heated to a temperature of 120 degrees Fahrenheit. Further, when producing a “double-backed” sheet of paperboard60, providing the second liner54at a temperature less than medium50and first liner52provides unexpected results that reduce warping and produce a flatter paperboard60.

As shown inFIG. 7, single facer machine300includes a first corrugating roller302, a second corrugating roller304, an adhesive roller306, and a single facing roller308. Corrugating rollers302,304define a portion of a corrugating device303. Single facing roller308and corrugating roller304define a portion of a paperboard facing device307. First and second corrugating rollers302,304are connected to frame58and extend laterally and substantially perpendicular to flow direction F of material50and define a portion of the sheet material pathway. Each of first and second corrugating rollers302,304include a plurality of teeth310that cooperate to nestingly fit in a series of complimentary peaks and valleys. The respective complimentary peaks and valleys of teeth310of each roller302,304meet at a corrugating nip312. Nip312therethrough defines a portion of the sheet material pathway. Material50flows through nip312and is corrugated into a sinusoidal shape by cooperating complimentary teeth310of rollers302,304. Roller302rotates about its axis in the same direction as flow F. Similarly, roller304rotates about its axis in the same direction as flow F.

Adhesive roller306is positioned closely adjacent corrugating roller304. Adhesive roller306contacts corrugated sheet50at the peaks to deposit a bead of adhesive314thereon. Adhesive roller306cooperates with an adhesive metering device316and an adhesive source318. Adhesive metering device316includes a metering rod320. Adhesive metering rod320includes similar threaded features as metering device134to meter the amount of adhesive rotatably applied to outer surface of roll306. As in metering device134, the metering rod320is adjustable to move towards or away from the outer surface of roll306to precisely set the gap therebetween. When the gap is set to near contact such that rod320is in near contact with applicator roll306, nearly all the adhesive is removed from the outer surface of roll306, excluding the adhesive322that passes through the channels142defined by threads138. Rod320may be adjusted for form a larger gap to allow nearly all adhesive to remain on the outer surface of rod320. Adhesive source318containing adhesive composition319is described in greater detail below with reference toFIG. 11.

Single facing roller308is in communication with a heat source315. Heat source315is preferably a compressed or pressurized steam device. Heat source315drives compressed steam into roller308in order to heat roller308. Heat source315may be connected to heat source214, or may be its own independent unit. As explained supra, the compressed steam pressure has an associated temperature, and thus heats up roll308containing the pressurized steam therein. The pressurized steam in communication with roll308should be less than 175 psi, and preferably is 150 psi. Steam in communication with roll pressurized at 150 psi imparts a temperature of about 365° F. to roll308. Roll308should not be heated to a temperature greater than 377° F. (the temperature of steam compressed to 175 psi).

With primary reference toFIG. 7, glue machine400includes an adhesive roll applicator402, a first roller404, and a second roller406, an adhesive metering device408having a metering rod410, and an adhesive source412. First and second rollers404,406define a portion of the sheet material pathway. Applicator402defines a portion of the sheet material pathway and is positioned substantially perpendicular to flow direction F. Applicator402is centered and rotates about an axis causing outer surface of applicator402to move in the same direction as flow F. Meter rod410is substantially similar to metering rod320and likewise adjustable as previously described herein supra to meter an amount of adhesive from source412to create an amount of surface adhesive414. Adhesive applicator402is positioned closely adjacent roll406such that adhesive414on the outer surface of roll402contacts the corrugated flutes to deposit a bead of adhesive416on the flutes opposite where bead318attaches liner52to medium50.

As shown inFIG. 8, double backer500includes a first roller502, a second roller504, a plurality of hot plates506operatively connected to a plate temperature (or pressurized steam) control system508, a drive system510, and a monitoring control system512. Double backer500is configured to attach second liner54to corrugated medium50via adhesive bead416. Double backer500is further configured to uniformly cool medium and liner material as the drive system510moves the formed paperboard60over hot plates506. Hot plates506cooperate to define a bottom boundary of the flow stream F and sheet material pathway.

First roller502is positioned vertically above second roller504defining a gap therebetween. Sheet material pathway flows through and is partially defined by the gap. Rollers502,504rotate about their respective axes such that the outer surface moves in the direction of the flow stream F. A pressure exerting device may be present to import an amount of pressure between material50and second liner54at bead416. Second liner54is pre-conditioned in100and heated in heating apparatus200(to a temperature not exceeding 130° F., and preferably 120° F.) prior to being fed into double backer500.

Control system508is in communication with a heat source509. Heat source509may be an independent system or it could be in communication with heat sources214and315. Preferably, Heat sources509,214, and315are derived from one pressurized steam generator. Control system508regulates the amount of pressurized steam driven to each respective plate within the set of hot plates506. Further, plates506define a storage chamber or passageway for containing pressurized steam therein. Similar to the heating rolls, the pressurized steam containment chamber within plates506imparts or transfers a desired temperature to the outer surface of the hot plates506.

In a preferred embodiment of present invention1000, hot plates506vary in temperature to cool and cure the adhesive. While not necessarily intuitive at first, the inventors have found that this non-uniform temperature hot plate arrangement actually encourages uniform evaporation from material50,52,54, to create paperboard60that is free from any warping. This arrangement has yielded fascinating and unexpected results over similar machines, such as the Kohler device identified in U.S. Pat. No. 8,398,802 and discussed supra in the Background. These prior art devices tend to use hot plates at temperatures exceeding 330° F. These temperatures tend to cause more steam to flash from the drying paperboard60, which can often lead to non-uniform evaporation. Hot plates506of the present invention are preferably all near or below 330° F. to reduce or even prevent the uneven flashing evaporation of steam leaving the paperboard60.

Two hot plates506may have a same temperature. Preferably, there are at least four hot plates506a,506b,506c,506darranged side-to-side from upstream to downstream, wherein the hot plate with the lowest temperature is positioned in the most upstream position of the four plates as in506a. In this arrangement the temperature of each plate does not decrease relative to the other plates from the upstream position to the downstream position. So by way of non-limiting example, a first plate506ais positioned in the most upstream position relative to the other hot plates506, having a temperature in a range from 312° F. to 320° F. (heated with pressurized steam at 65 psi to 75 psi); a second plate506bis positioned downstream from the first plate506ahaving a temperature in a range from 320° F. to 328° F. (heated with pressurized steam at 75 psi to 85 psi); a third plate506cis positioned downstream from the second plate506bhaving a temperature in a range from 320° F. to 328° F. (heated with pressurized steam at 75 psi to 85 psi); and a fourth plate506dis position downstream from the third plate506chaving a temperature in a range from 328° F. to 333° F. (heated with pressurized steam at 85 psi to 95 psi). Further preferably, additional embodiments include wherein no hot plate506has a temperature exceeding about 330° F. (heated with pressurized steam at 90 psi). More specifically, the first hot plate506atemperature is 316° F. (heated with pressurized steam at 70 psi), the second hot plate506bis 324° F. (heated with pressurized steam at 80 psi), the third hot plate is 324° F. (heated with pressurized steam at 80 psi), and the fourth hot plate is 330° F. (heated with pressurized steam at 90 psi). These temperatures are controlled by temperature control system508operatively connected to each respective plate506. Control system508may contain computer logic software or other integrated software to operate free from human monitoring.

One or more moisture measurement devices514,516and corresponding control system512can be used for one or all materials50,52,54to be heated to provide a closed loop control of moisture in each individual sheet of material50,52,54that make up completed paperboard60. Further, drive system510may include a plurality of drive rollers to move a belt518in a loop to move formed paperboard60over hot plates506. Control system512may contain computer logic software or other integrated software to operate free from human monitoring.

The term “logic”, as used herein, with reference to control systems280(FIG. 5), refers to and includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another logic, method, and/or system. For example, based on a desired application or needs, logic may include a software controlled microprocessor, discrete logic like a processor (e.g., microprocessor), an application specific integrated circuit (ASIC), a programmed logic device, a memory device containing instructions, an electric device having a device to read a software medium, or the like. Logic may include one or more gates, combinations of gates, or other circuit components. Logic may also be fully embodied as software. Where multiple logics are described, it may be possible to incorporate the multiple logics into one physical logic. Similarly, where a single logic is described, it may be possible to distribute that single logic between multiple physical logics

As shown inFIG. 10, paperboard60upon exiting double backer500dries at an even rate and contains no warping when viewed from the side. The term no warping refers to a sheet of manufactured paperboard60that is substantially flat and planar with no deflection upwardly or downwardly. As shown inFIG. 10, paperboard60further has even and uniform adhesive lines which form a proper lamination between components50,52,54which make up paperboard sheet60.

With primary reference to adhesive source318andFIG. 11, adhesive source318includes an adhesive composition319comprising: water1102, a rheology modifier or additive1104, a starch1106, a caustic or alkaline hydroxide1108, at least one borate1110, a biocide1112, a defoamer1114, and a penetrating agent1116. These components are mixed together in distinct time intervals1101,1103,1105,1107, and1109. Further, during adhesive319manufacture (described in detail below), some components are heated1115to a first temperature1125, then more components are added, and the mixture re-heated1113to a second temperature1127.

Water1102is preferably drawn from a municipal source, however clearly other water sources providing potable or filtered non-potable water are entirely possible. Preferably, a second amount of water1111and flush water1118used during the production of adhesive compound319can be drawn from the same water source as1102.

Rheology modifier1104is a high molecular weight water-soluble polymeric material. The rheology modifier1104can be either a synthetic polymer or a naturally occurring polymer. Examples of synthetic high molecular weight water-soluble polymeric materials are carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, polyvinylacrylic acid polyacrylamide, polyvinyl alcohol, and polyoxyethylene. Examples of naturally occurring high molecular weight water soluble polymeric materials include xanthan gum and guar gum. The rheology modifier in the Stein Hall adhesive composition of the present invention modifies the rheology of the composition in such a manner that up to a 50% decrease in the amount of adhesive composition is applied. For example, this can be accomplished by setting the metering gap on the adhesive composition applicator rolls to be decreased by up to 50%, thereby lowering the amount of adhesive placed on the flute tip by up to 50%. The term “synthetic polymer” as used herein refers to a compound that is chemically made and can be used as a rheology modifier. Synthetic polymer compounds can include carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, polyvinyl acrylic acid, polyacrylamide, polyvinyl alcohol, and polyoxyethylene. The term “naturally occurring polymer” as used herein refers to a compound that is found in nature that can be used as a rheology modifier. Naturally occurring polymer compounds can include xanthan gum and guar gum.

Starch1106refers to a carbohydrate having a large number of glucose units joined together through glycosidic bonds as a polysaccharide. Starches can be modified chemically or used without modification (i.e., naturally occurring). Modified starches are native starches which have been modified e.g. by enzymatic, chemical and/or heat treatment and include, by way of example only, oxidised starches, acid-thinned starches, esterified starches, etherified starches, dextrins, maltodextrins, cross-linked starches and the like. A “gelatinized starch” is a starch compound where heat or chemicals such caustic1108is applied or added to it. It is sometimes referred to as the primary or carrier starch as it is often the first starch compound added to the adhesive composition. A secondary starch1122may refer to the same or another type of starch as1106.

Caustic1108refers to a compound that contains the anion [OH]. This can include compounds by way of non-limiting example, sodium hydroxide, potassium hydroxide, calcium hydroxide, and the like. Borate1110refers to a chemical compound containing boron ions, including but not limited to, sodium borate, sodium tetraborate, and disodium tetraborate. Further, a second borate1120or secondary borax may refer to the same or another type of borate as1110in the manufacture of adhesive composition319.

Biocide1112is a chemical agent designed to kill or reduce mold and bacteria not only within adhesive compound319but throughout system1000. Biocide1112assists in eliminating the mold and bacteria naturally exposed to starch1106during the manufacture of adhesive318. The mold and bacteria have devasting results if left untreated, for example, if bacteria are left untreated, it will spread throughout system1000making the bonding process extremely difficult. By way of non-limiting example, biocide1112may be one of or a combination of B-141®, Proxel® GXL, and KK™909, all manufactured and distributed by Corrugated Chemicals Incorporated of Knoxville, Tenn. Biocides are often commercially available in both liquid and powdered form, each of with are contemplated for use herein.

Defoamer1114is a composition, preferably wholly organic, that provides rapid foam reduction. Defoamer1114does not affect the viscosity of starch1106when mixed within adhesive318. Preferably, defoamer1114is one or more of the following: a rapid response of foam created during adhesive manufacture; long lasting; of a food grade organic quality; and capable of being pumped. By way of non-limiting example, defoamer1114can be one of or a combination of No-Foam™211 and No-Foam™ 315, both of which are manufactured and distributed by Corrugated Chemical Incorporated, of Knoxville, Tenn.

Penetrating agent1116is a compound configured to overcome the hard-to-penetrate mediums50and liners52,54often used in paperboard manufacturing process. Medium50and liners52,54often contain some amount of recycled fiber and softwood, which makes them difficult to process by a corrugator. Essentially, recycled mediums50and recycled liners52,54are more stiff than conventional paper free of recycled products. The recycled products also make it difficult to product a quality bond with adhesive318because the mediums50and liners52,54having recycled products prevent starch1106from penetrating the paper fiber, which is critical for a strong bond to occur. By way of non-limiting example, penetrating agent1116can be any one of or a combination of Bond-Aid® and Bond-Aid® Plus, both of which are manufactured and distributed by Corrugated Chemical Incorporated, of Knoxville, Tenn.

FIG. 12depicts a box diagram flow chart of a method of manufacturing an adhesive compound, shown generally as1200. The method1200comprises the steps of: providing an amount of water contained within a source container, shown as1202; heating the water to a first temperature, shown as1204; adding a rheology modifier to the heated water to create a heated solution, shown as1206; adding a starch to the heated solution, shown as1208; and mixing the heated solution for a first period of time to create a heated mixture, shown as1210. Additional dependent steps from method1200are described in greater detail below. Method1200is shown for exemplary purposes only, it is clearly understood that additional steps may be added thereto or some of the enumerated steps to be removed therefrom.

In accordance with one aspect of an embodiment, the present invention provides a method for producing an adhesive using a non-continuous mix cycle or multiple distinct mixing time periods. Namely, rather than mixing all components of the adhesive318together for a period of time (i.e., eight minutes as taught by the '049 Application), the present invention provides a staggered mixing cycle broken into a plurality of distinct mixing cycles.

In accordance with an additional aspect of an embodiment, the present invention provides a method of producing an adhesive that will bond with liner54at a desired temperature. Namely, adhesive composition319manufactured with the distinct mixing time periods allows adhesive319to bond with second liner54heated to a temperature around 120° F., rather than the required liner temperature of 70° C.-90° C. (158° F.-194° F.) taught in the '049 Application.

In operation and with primary reference toFIG. 5, a web of medium material50is fed into the medium conditioning apparatus100from a source102, preferably a paper roll for making paperboard or cardboard as is commonly known in the art. Upon entering the medium conditioning apparatus100, material50can be first fed through a pre-tensioning mechanism110and then passed through a pre-wetting moisture application roller120. Moisture application roller120contacts and applies liquid or moisture to the medium material50to adjust its moisture content in a desired range prior to exiting apparatus100.

Some exemplary moisture ranges claimed in the Kohler '802 patent are in the range of 6-9% wt. System1000can operate outside of these moisture ranges when necessary, either lower than 6% wt. or higher than 9% wt. For example, when material50is flowing F, roll120is configured to apply or otherwise impart a moisture content into material50in the range of 10-18% wt. Additionally, if either liner52or second liner54is flowing F through conditioning apparatus100, roll120is configured to impart a moisture content in the range of 32-42% wt into liner52or second liner54.

In operation and with continued reference to the moisture applicator roller120, when the flowing F linear velocity50vof material50is plotted against the tangential velocity120vta value exists indicating the tangential velocity percentage in a threshold range. While a previously given example provided alternative threshold ranges, the following ranges are also contemplated. When the medium material50is flowing F within a first threshold range from about 1 foot per minute (FPM) to about 100 FPM, the tangential velocity120vtof the outer surface of the applicator roll120is about 100% of the linear velocity of the medium material50. When the medium material50is flowing within a second threshold range from about 100 FPM to about 300 FPM, the tangential velocity120vtof the outer surface of the applicator roll120is about 80% of the linear velocity of the medium material50. When the medium material50is flowing within a third threshold range from about 300 FPM to about 500 FPM, the tangential velocity120vtof the outer surface of the applicator roll120is about 70% of the linear velocity of the medium material50. When the medium material50is flowing within a fourth threshold range from about 500 FPM to about 800 FPM, the tangential velocity120vtof the outer surface of the applicator roll120is about 55% of the linear velocity of the medium material50. And, when the medium material is flowing within a fifth threshold from about 800 FPM and faster, the tangential velocity120v1of the outer surface of the applicator roll120is about 45% of the linear velocity of the medium material.

It is further to be understood that first liner52is pre-conditioned or pre-wetted in a manner similar to medium material50. For example, with reference toFIG. 7where liner52flows “FROM200” a sheet of liner material52flows along a liner material pathway at a linear velocity, and configured to adhere to a first fluted side of the corrugated medium material50. A second applicator roll, similar to roll120, rotatably connected to the frame and positioned adjacent the liner material pathway and upstream from where the liner material is adhered to the corrugated medium material at314along the liner material pathway. The second applicator roll is configured to apply a liquid to the flowing liner material52. The second applicator roll has a length and a radius, wherein the second applicator roll rotates about a second axis at an angular velocity, and wherein an outer surface of the second applicator roll travels at a tangential velocity as the second applicator roll rotates. The second applicator roll transfers the liquid to the sheet of liner material52as the liner52flows by and adjacent the second applicator roll along the liner material pathway. A second metering device, similar to130, adjacent the second applicator roll meters an amount of the liquid onto the second applicator roll. Similar to120and130, the amount of liquid metered onto the second applicator roll depends on the angular velocity of the second applicator roll. Further, the tangential velocity of the second applicator roll is a percentage of the linear velocity of the flowing liner material52.

Additionally, a second series of speed threshold ranges exist, the second threshold ranges defining a numerical boundary for a percentage amount of the tangential velocity of the second applicator roll relative to the linear velocity of the liner material52, thereby determining the amount metered liquid applied to the second applicator roll, the ranges including: a first range from about 1 foot per minute (FPM) to about 150 FPM; a second range from about 150 FPM to about 350 FPM; a third range from about 350 FPM to about 650 FPM; a fourth range from about 650 FPM to about 1000 FPM; and a fifth range from about 1000 FPM to about 20,000 FPM. The linear velocity of the flowing liner material52is within one of the first, second, third, fourth, and fifth ranges. The speed thresholds form a stepwise graph function such that the tangential velocity of the second applicator roll is the same for any liner velocity within a respective step of the stepwise graph function. When the linear velocity of the flowing liner material52is within the first range, the tangential velocity of the second applicator roll is about 140% to about 30% of the linear velocity of the flowing liner material52. When the linear velocity of the flowing liner material52is within the second range, the tangential velocity of the second applicator roll is about 130% to about 15% of the linear velocity of the flowing liner material. When the linear velocity of the flowing liner material52is within the third range, the tangential velocity of the second applicator roll is about 110% to about 7% of the linear velocity of the flowing liner material. When the linear velocity of the flowing liner material52is within the fourth range, the tangential velocity of the second applicator roll is about 90% to about 4% of the linear velocity of the flowing liner material. When the linear velocity of the flowing liner material52is within the fifth range, the tangential velocity of the second applicator roll is about 75% to about 2% of the linear velocity of the flowing liner material52.

It is further to be understood that second liner54is pre-conditioned or pre-wetted in a manner similar to medium material50. For example, with primary reference toFIG. 9where second liner54flows “FROM200” the sheet of second liner material54flows along a second liner material pathway at a linear velocity, and configured to adhere to the corrugated medium material50along a second fluted side opposite the first liner material at bead416. A third applicator roll, similar to120, is rotatably connected to the frame and positioned adjacent the second liner material pathway and upstream from where the second liner material54is adhered at314to the corrugated medium material50along the second liner material pathway, wherein the third applicator roll is configured to apply a liquid to the flowing second liner material and the third applicator roll having a length and a radius. The third applicator roll rotates about a third axis at an angular velocity, and wherein an outer surface of the third applicator roll travels at a tangential velocity as the third applicator roll rotates. The third applicator roll transfers the liquid to the sheet of second liner54material as the liner54flows by and adjacent the third applicator roll along the liner material pathway. A third metering device, similar to130, adjacent the third applicator roll meters an amount of the liquid onto the third applicator roll. The amount of liquid metered onto the third applicator roll depends on the angular velocity of the third applicator roll. The tangential velocity of the third applicator roll is a percentage of the linear velocity of the flowing second liner material54.

With continued reference to the third applicator roll, a third series of speed threshold ranges exist, the ranges defining a numerical boundary for a percentage amount of the tangential velocity of the third applicator roll relative to the linear velocity of the second liner material54, thereby determining the amount metered liquid applied to the third applicator roll, the ranges including: a first range from about 1 foot per minute (FPM) to about 150 FPM; a second range from about 150 FPM to about 350 FPM; a third range from about 350 FPM to about 650 FPM; a fourth range from about 650 FPM to about 1000 FPM; and a fifth range from about 1000 FPM to about 20,000 FPM. The linear velocity of the flowing second liner material54is within one of the first, second, third, fourth, and fifth ranges. The speed thresholds form a stepwise graph function such that the tangential velocity of the third applicator roll is the same for any second liner54velocity within a respective step of the stepwise graph function. When the linear velocity of the flowing second liner material54is within the first range, the tangential velocity of the third applicator roll is about 160% to about 60% of the linear velocity of the flowing second liner material54. When the linear velocity of the flowing second liner material54is within the second range, the tangential velocity of the third applicator roll is about 150% to about 40% of the linear velocity of the flowing second liner material54. When the linear velocity of the flowing second liner material54is within the third range, the tangential velocity of the third applicator roll is about 140% to about 13% of the linear velocity of the flowing second liner material54. When the linear velocity of the flowing second liner material54is within the fourth range, the tangential velocity of the third applicator roll is about 130% to about 5% of the linear velocity of the flowing second liner material54. And, when the linear velocity of the flowing second liner material54is within the fifth range, the tangential velocity of the third applicator roll is about 115% to about 1% of the linear velocity of the flowing second liner material54.

In operation and with primary reference toFIG. 6, idle roller202directs or guides sheet material50towards heat roll212. Outer surface of heat roll212contacts sheet material50as material50flows circumferentially around and along outer surface of heat roll212making substantial contact therewith. The amount of time sheet material50is in contact with the outer surface of heat roll212is known as the dwell time. Dwell time may be increased or decreased depending on the amount of heat desired to be transferred to paper web50. As briefly detailed above, if medium material50is flowing over heat roll212, medium50is heated to a temperature in a range from 150 degrees Fahrenheit to 170 degrees Fahrenheit (as shown inFIG. 6;50flowing F “FROM200”). If first liner52is flowing over heat roll212, first liner52is heated to a temperature in a range from about 185 degrees Fahrenheit to about 205 degrees Fahrenheit (as shown inFIG. 6;52flowing F “FROM200”). If second liner54is flowing F over heat roll212, second liner54is heated to a temperature up to but not exceeding about 130 degrees Fahrenheit (as shown inFIG. 8;54flowing F “FROM200”).

Web50exits and leaves heat roll212passing along, over and around various idle rollers, shown as204,206towards drive roller216. Drive roller216is preferably a suction roller as known and understood in the art. Suction roller216has a perforated outer surface to create a linear tension on web50as it travels downstream. A zero contact drive roller218is positioned between idle rollers208and210. Zero contact roll218can be a stationary roller that does not rotate as the web of material traverses its circumferential surface. Instead, a volumetric flow rate of air at a controlled pressure is pumped from within the zero contact roll218radially outward through small openings or holes provided periodically and uniformly over and through the outer circumferential wall of the zero contact roll218. The passing web of medium material50is supported by the circumferential outer surface of the zero contact roll218by a cushion of air.

In operation, and with primary reference toFIG. 6, the flowing material50flows along the sheet material pathway in the direction of arrow F. Material50flows around the outer surface of corrugating roller302. Material50flows through nip312where it begins to be corrugated. The complimentary peaks of teeth310on roller302and valleys of teeth310of roller304interlock to sandwich material50therebetween. The interlocking teeth form the sinusoidal shape of material50. Material50continues to move downstream towards the adhesive application roller306.

Adhesive application roller306rotates about its axis into a pool318of adhesive319. The pool is in contact with outer surface of roller306. As roller306rotates, adhesive is metered (metered adhesive322) by metering rod320onto the outer surface of roll306. Metered adhesive322is a precise amount and can specifically vary depending on each desired application by adjusting rod320relative to surface of roll306. The amount of metered adhesive322determines the thickness or amount of adhesive bead314applied to the flute tip of corrugated sheet50.

Corrugated sheet50having bead of adhesive314moves towards roll308. Roll308receives a first liner52from a feed source or from heating device200. Material52flowing around roll308contacts material50under pressure. Material50adheres to the flat or planar liner52. The pressure may be applied via a pressure exerting device or roll308within the paperboard facing machine300to exert a pressure on the web of medium material flowing downstream F as the web50is adhered to the liner52. The pressure exerted within facing machine300by pressure exerting device or roll308on the flowing web of medium material50and first liner52is from about 65 bar to about 85 bar. Preferably, the pressure is about 75 bar.

In operation and with primary reference toFIG. 7, corrugated medium50adhered to first liner52flows F from single facing machine300to double backer500along the sheet material pathway. When medium50is adhered to liner52it is known as a Single Face. Single Face flows around roller404towards roller406where adhesive414may be applied to create a bead416on the corrugated flute of medium50. Adhesive roller402rotates in the direction flow stream F through an adhesive source412. Adhesive source412includes starch and water, as well as other additives and modifiers as understood in the art.

In operation and with primary reference toFIG. 8, Single Face flows FROM400(adhesive applicator400) having first liner adhered to corrugated medium50and having a bead of adhesive416deposited on the flutes opposing liner. Single Face flows towards toward the gap defined by first and second rollers502,504. Second liner54flows FROM200(heating apparatus200) and also flows toward the gap defined by first and second rollers502,504. Single Face (medium50adhered to liner52) meet and connect to second liner54in the gap defined by rollers502,504. Rollers502,504apply pressure and effectively pinch together second liner54to the flutes of medium50at bead416. Bead of adhesive416adheres second liner54to medium50creating a “double-backed” sheet of paperboard. The term double-backed refers to a sheet of manufactured paperboard60having two liners52,54sandwiching a sinusoidally shaped medium material50.

Formed paperboard60continues to flow F downstream. The upper portion of paperboard60(formerly first liner52) contacts belt518. Belt518is part of a drive system510configured to move paperboard60downstream. Drive system510may be powered via conventional manners as understood in the art of paperboard manufacturing. The lower portion of paperboard60(formerly second liner54) flows downstream above hot plates506.

Hot plates506are controlled by the steam pressure and temperature control system508. Control system508controls the temperature of each plate506a,506b,506c,506dwithin the set of hot plates506through the use of pressurized steam from source509, independent of the remaining hot plates within the set. The pressurized steam is contained within each plate to impart a temperature to the outer surface. The plates506may include at least four hot plates506a,506b,506c, and506d. The plates are arranged in a side-to-side manner from upstream to downstream. The plates vary in temperature from upstream to downstream. When viewed from the side (FIG. 8) the plate foremost upstream plate506ais the coolest relative to the other plates. Looking at the downstream plates506b,506c,506d, the temperature may stay equal to the prior plate, or the temperature may increase. The temperature of a plate is never less than the plate directly upstream from it. So by way of non-limiting example, for a Single Face sheet of material (medium50adhered to liner52without second liner54) flowing F over plates506and if plate506ais 320° F. (heated with 75 psi steam), then plate506b(the plate directly downstream from plate506a) must be at least the same temperature or hotter than 320° F. Stated otherwise, plate506bcannot be cooler than506a. If plate506bis 328° F. (heated with 85 psi steam), then plate506c(the plate directly downstream) cannot be cooler than 328° F. (it may be equal to 85 degrees). Thus, if plate506cis also 328° F. (heated with 85 psi steam), then plate506d(the plate directly downstream) cannot be cooler than 328° F. and is preferably about 330° F. Additionally, the set of hot plates506may be configured such that each hot plate506a,506b,506c,506dhas a temperature not equal to any other plate in the set of hot plates506.

Alternatively, by way of non-limiting example, for a double backed sheet of paperboard60, the temperatures for the hot plates506may be slightly hotter than those described above for a Single Face. Thus, when a double backed sheet of paperboard60is formed by System1000, when plate506ais 330° F. (heated with 90 psi steam), then plate506b(the plate directly downstream from plate506a) must be at least the same temperature or hotter than 330° F. Stated otherwise, plate506bcannot be cooler than506a. If plate506bis 338° F. (heated with 100 psi steam), then plate506c(the plate directly downstream) cannot be cooler than 338° F. (it may be equal to 338 degrees). Thus, if plate506cis also 344° F. (heated with 110 psi steam), then plate506d(the plate directly downstream) cannot be cooler than 344° F. and could be about 355° F. (heated with 130 psi steam). The hot plates506for a double backed paperboard are all preferably less than or equal to 350° F. (heated with 120 psi steam)

Hot plates506cool paperboard60flowing atop to cure the adhesive applied in single facer300, and applied in adhesive applicator400. The configuration of hot plates506ensure paperboard60should not warp while uniformly drying (FIG. 9). Further, this configuration should produce even adhesive lines to prevent delamination (FIG. 10).

In operation and with primary reference toFIG. 11, adhesive composition319stored in adhesive source318(FIG. 6) is manufactured by the shown steps. By way of non-limiting example, two Formulas: Formula 3 Single Face (SF) and Formula 4 Double Back (DB), are provided with reference to the method of manufacturing adhesive319. In the manufacture of adhesive319, first a user should provide an amount of water1102contained within a source container. For each of Formula 3 and Formula 4, 110 gallons of water1102having a weight of 916 lbs is provided. Then water1102should be heated1115to a first temperature1125. The first temperature1125is less than 120° F. and preferably in a range from about 105° F. to about 115° F. As shown inFIG. 11, the first temperature1125of Formula 3 is 112° F. and of Formula 4 is 111° F.

Then, a rheology modifier1104is added to the heated water1102to create a heated solution. For each of Formula 3 and Formula 4, 46 pounds of additive or modifier1104is added. Next, starch or pearl starch1106is added to the heated solution. For Formula 3, 107 pounds of starch1106is added, and for Formula 4, 91 pounds of starch1106is added. Also, caustic1108is added to heated solution. For formula 3, 23.5 pounds of caustic1108is added, and for Formula 4, 29.3 pounds of caustic1108is added. Then, the heated solution is mixed for a first period of time1101to create a heated mixture. As shown inFIG. 11, the first time period1101is about 3 minutes for each of Formula 3 and Formula 4. The rheology modifier1104is from about 2.5% to about 6% solids by weight (% wt. solids) of the heated solution. As shown, modifier1104is 4.2% wt. solids for Formula 3 (46 pounds/1093 pounds=4.2%) The starch1106is from about 7.5% wt. solids to about 12% wt. solids of the heated solution. As shown, starch1106is 9.7% wt. solids for Formula 3 (107 pounds/1093 pounds=9.7%). Caustic1108is from about 1% wt. solids to about 4% wt. solids. As shown in Formula 3, caustic1108is 2.15% wt. solids (23.5 pounds/1093 pounds=2.15%)

After the heated solution is mixed, then primary borax or borate1106is added to the heated mixture. Four pounds of borate1106is added for Formula 3, and for Formula 4, 7 pounds of borate1106is added. Then, the heated mixture is mixed for a second period of time1103. Preferably, the second time period1103is about 2 minutes. The borate is from about 0.1% wt. solids to about 1% wt. solids of the heated mixture. As shown, borate1110is 0.3% wt. solids of the heated mixture (4 pounds/1097 pounds=0.3% wt. solids)

After, mixing the heated mixture for a second time period1103, a second amount of water1111is added. For Formula 3, 158 gallons are added and for Formula 4, 160 gallons are added. The second amount of water111is 135% to about 150% the first amount of water (158 gallons/110 gallons=144%). The heated mixture is then re-heated1113to a second temperature1127, wherein the second temperature1127is a range from about 90° F. to about 100° F. For each of Formula 3 and Formula 4, second temperature1127is 94° F. Then, the heated mixture is flushed with an amount of flush water1118. Flush water1118refers to an amount of water added after the second reheating1113. For each Formula 3 and Formula 4, 25 gallons of flush water1118are added to the heated mixture. Flush water1118does not leave the heated mixture, the term “flush” refers to water added to the heated mixture after the second reheating1113. The amount of flush water1118is from about 14% to about 18% the second amount of water, as shown 25 gallons/158 gallons=15.8%.

A secondary borate or secondary borax1120is then added. For Formula 3, 2.5 pounds of secondary borax1120are added, and for Formula 4, 7 pounds of secondary borax1120are added. The second borax1120is from about 50% to about 100% of the amount of first borax1110. For example, in Formula 3 2.5 pounds of secondary borax is 62.5% of the amount of primary borax. (2.5 pounds/4 pounds=62.5%) And, for Formula 4, secondary borax is 100% of the amount of primary borax. (7 pounds/7 pounds=100%)

After secondary borax1120, a second starch1122is added. For Formula 3, 520 pounds of second starch1122is added, and for Formula 4, 581 pounds of second starch1122is added. Second starch1122is an amount that is from about 450% to about 650% the amount of pearl starch1106. For example, in formula 3 second starch1122is 485% the amount of primary starch1106(520 pounds/107 pounds=485%). In Formula 4, the second starch is 638% the amount of primary starch1106(581 pounds/91 pounds=638%). The heated mixture is then mixed for a third period of time1105. Preferably, the third period of time1105is one minute.

After the step of mixing the heated mixture for a third period of time1105, the biocide1112is added to the heated mixture. For Formulas 3 and 4, 3 pounds of biocide1112are added. 3 pounds of biocide1112is about 0.1% solids by weight (% wt. solids) of the entire adhesive compound. The defoamer1114is added to the heated mixture in a 3 ounce amount to each of Formula 3 and 4. The mass amount of defoamer1114(3 ounces) is 6.25% of the mass amount of biocide1112(3 pounds or 48 ounces). The penetrating agent1116is then added to the heated mixture. Preferably, about 17 ounces of penetrating agent1116is added. The mass amount of penetrating agent1116(17 ounces) is about 35.4% of the mass amount of biocide1112(48 ounces). Then, the heated mixture is mixed for a fourth period of time1107. Preferably, the fourth period1107of time is one minute.

Subsequent to the step of mixing the heated mixture for a fourth period of time1107, the heated mixture is mixed for a fifth period1109of time, wherein the fifth period1109of time is 2 minutes, to create the adhesive compound. In the preferred method embodiment, time periods1101,1103,1105,1107,1109are separate and distinct (i.e., non-continuous) from one another. The term “time periods” refers to the time in which a mixing device (not shown) is actually moving within a source container to mix the contents together. The breaks in time between operating the mixing device, so that the adhesive319components may be added to the container, create and define the separate and distinct time periods1101,1103,1105,1107,1109. By way of non-limiting example, when the mixing device is not operating (i.e., turned off momentarily) after third time period1105, the biocide, the defoamer, and the penetrating agent may be added, and thus creating a non-continuous time segment.

The method for manufacturing adhesive319detailed inFIG. 11results in producing an adhesive having desirable quality specifications. Namely, a desired starch gel temperature, a desired viscosity, and a desired amount of solids by weight (% wt. solids). By way of not limiting example, a desirable quality specification starch gel temperature for Formula 3 is 143° F.-145° F. and for Formula 4 139° F.-141° F. A desirably viscosity amount of adhesive319for both Formula 3 and Formula is 23+/−3 Love Cup. A desirable % wt. solids for Formula 3 is 21.7% and for Formula 4 is 22.8%.

Moreover, the description and illustration of the preferred embodiment of the invention are an example and the invention is not limited to the exact details shown or described.