JP2003533599A - Method of coating cardboard with water-dispersed polyester polymer - Google Patents

Abstract

(57) coating the cardboard (14) and heating the cardboard (14) at a heating station (20) to a temperature sufficient to remove at least some moisture from the cardboard (14); Applying a dispersion of at least one water-dispersed polymer to the cardboard (14) at a coating station (24); heating the cardboard at a drying station (26, 30) to cure at least a portion of the water-dispersed polymer; And cooling the cardboard (14) to at least 160 ° F. to reduce the stickiness of the cured water-dispersed polymer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to a method and apparatus for coating cardboard, and more particularly to producing a coated cardboard product having low moisture vapor transmission rate (MVTR), good adhesion ability, printing ability and recycling ability. The present invention relates to a method and an apparatus.

[0002]

[Prior Art and Problems to be Solved by the Invention]

Corrugated board is a processed or remanufactured paper product. Also, corrugated board typically has a layered structure that is stamped to form a cardboard box. Corrugated board consists of corrugated media with grooves that are sandwiched between sheets of cardboard base paper. The simplest three-layer structure is known as "double-sided". Until recently 1990
Many corrugated cardboards consist entirely of virgin, long fiber, softwood, kraft pulp. However, today, these paper grades include old cardboard boxes (OCCs) that are reclaimed to a large extent and often consist of 100% OCC.

[0003] In Japan and around the world, the space for waste disposal sites for waste disposal is rapidly approaching the limit capacity. By 2000, paper and corrugated board products will reach 40.9% of the municipal solid waste stream, and by 2010 may increase to almost 42%. With the increasing public interest in new country regulations and the environment,
There is pressure to remove these materials from the solid waste stream. Recycling is the most widely used method for reducing paper waste.

OCC has a history of efficient recycling use. Even before the time of government mandates and industrial purposes, about 50% of OCC was recycled in North America. Today's regeneration rate is about 62%. It is expected to reach the 70% level in 2000. Today, most of this recycled material is shipped directly from retailers to manufacturing plants under long-term contracts. The rest comes from waste collection outlets and wastepaper dealers on the edge of the city streets. Some OCC is used in the manufacture of cardboard boxes and some is bleached in the manufacture of good quality paper, but many OCC
Is again used to produce corrugated media and corrugated board.

“Repulping” means any mechanical action that disperses dried or compacted pulp fibers in a water muddy, slurry or suspension. This effect is sufficient to pump the slurry and to completely separate and disperse all fibers. In a typical recycling process, a plurality of "dust" OCCs are fed to a repurper where the material is decomposed and all contaminants are removed. The resulting stock is pumped through a pressure screen and cyclone vacuum to remove oversized material and debris. The adhesive, staples, wax and tape used to assemble the cardboard box must be removed.

Untreated OCC usually has no recycling issues. However, cardboard is often treated or coated to enhance its performance, which renders the paper non-recyclable. For example, corrugated cardboard is often treated with curtain coating, wax impregnation, laminating, sizing or aqueous coatings to reduce friability and impart oil and water resistance. While wax-like coatings enhance the water resistance of cardboard, the wax coating process is expensive and often renders cardboard non-recyclable. Therefore, there is a need in conventional coating systems to enhance the ease of use of cardboard boxes and to allow the containers to be recycled.

Various coatings have been introduced to the market to provide recyclable coatings, but they are subject to limitations such as printability and adhesiveness. Multiple repulpable coatings cannot be printed due to high water resistance or the release properties of the coating. Some repulpable coatings are printable, but require special inks. Even more problematic, many currently available repulpable cardboard coatings are not compatible with all adhesives. For example, some coatings are only compatible with hot melt adhesives, while others repel oily hot melt adhesives because of their heat and oil resistant properties. Therefore, there is a need in conventional coating systems to be compatible with a wide range of printing and adhesive systems.

Water vapor transmission rate (MVTR) is a physical quantity used to describe a product's ability to pass water vapor at a controlled temperature and a specified atmospheric pressure for a specified time. Various products such as frozen meat pies and fine paper are extremely sensitive to changes in moisture (moisture). In the case of meat pies, excessive moisture loss during the product's storage in the freezer results in "freezer baking". Freezer burns are invisible but affect the taste of cooked meat. For fine paper, excessive moisture build-up softens the sheets made in the hard process. Conventional approaches generally include a plastic membrane as a layered structure with paper or as a container for the product. Either approach is expensive or incurs additional labor costs and significantly reduces or loses the recycling capacity of the container. Therefore, in the prior art of coatings, there is a need to be able to provide the required high water resistance without losing the recycling capacity of the container.

The MVTR of a container depends not only on the coating on corrugated cardboard but also on the method of applying the coating. Conventional methods of coating, such as red or blue coaters, can result in changes in coating thickness that lead to changes in the MVTR of the coating. The usual strategy for this problem is to simply increase the amount of coating applied to the cardboard. This measure is expensive and does not result in a coated product which is conditioned linearly and transversely to the web. Therefore, MVT
There is a need for a method of uniformly coating (applying) cardboard with little change in R.

[0010]

[Means for Solving the Problems]

Therefore, it is an object of the present invention to provide a coating system that can reduce the MVTR of cardboard products and recycle the products.

Another object of the invention is to provide a coating system that is compatible with a wide range of printing and adhesive systems.

Another object of the present invention is to provide a method for applying a uniform coating to cardboard such that the MVTR is hardly changed.

It is an object of these and other objects of the invention to provide a method and apparatus for producing coated cardboard with low MVTR, good adhesion, printability and recyclability.

The method of the present invention comprises the steps of flame treating a cardboard product to remove surface fibers, preheating the cardboard product, coating with a water-dispersed polymer suspension by an air knife coater, and drying the coating. And heating the coated cardboard product to cure, and cooling the cardboard product.

The apparatus of the present invention comprises a flame treatment means, a heating means, an outer surface (contour) coating means for applying a water-dispersed polymer to at least one surface of a cardboard product, a drying means for curing the coating, and a cardboard product. Cooling means for lowering the temperature of the coating.

[0016]

DETAILED DESCRIPTION OF THE INVENTION

For a general description of the subject matter of the present invention, reference is made to the accompanying drawings in which a schematic diagram of a preferred embodiment, and more specifically of a device corresponding to the invention, is shown.

FIG. 1 shows a schematic diagram of an apparatus 100 and method for producing a coated cardboard product. The device 100 may be in-line (i.e., part of the cardboard making machine) or offline. If the apparatus 100 is offline, the cardboard is unrolled from the stock roll 10 and fed to the gluing apparatus assembly 12. The gluing device assembly 12 joins the end of one roll of cardboard to a second roll to allow continuous processing between rolls.

As used herein, “cardboard” refers to a sheet of cellulosic fiber web. The cardboard used in the present invention is generally a cardboard suitable for folding cartons or corrugated board and may be a substrate for laminating to a backing such as gypsum board. The term cardboard includes different thicknesses of paper and cardboard. Suitable cardboard is virgin kraft cardboard known as corrugated liner (board stock). As is well known in the art, kraft cardboard can be produced by a chemical treatment process using sodium hydroxide and sodium sulfide, and many different types of kraft cardboard are produced using different additives and treatments for different applications. To be done. The present invention may utilize reworked cardboard, ie, used kraft cardboard.

Surface treatments may be used as part of the conversion process to alter the surface properties of the particular material used. A typical surface treatment process involves altering the wettability of the substrate and improving the integrity of the applied material or the removal of accumulated electrostatic charge. Surface treatment techniques can play an important role in preparing the surface of cardboard in successive process steps. The cardboard 14 is sent from the gluing device 12 through the flame processing means.
Here, the flame treatment means flames the surface to be coated with one or more gas burners to burn the free-ended fibers and debris to reduce the water content of the paper. The flame treatment of the present invention has several advantages. Most importantly, it provides a better paper surface by baking open-ended fibers and other surface deposits that interfere with the continuous coating. If not removed by flame treatment, the open-ended fibers are an obstacle to the coating, providing a path for moisture to pass through the coating. This process, commonly referred to as wicking, will drive moisture through the coating along the free-end fibers into the cardboard. This not only weakens the cardboard,
This will provide a cardboard product that is poorly waterproof.

Furthermore, by preventing moisture from wicking through the corrugated board coating and by preventing moisture from penetrating the coating under severe humidity or water impregnation conditions, flame Treatment is very important for the ultimate strength of wet cardboard. Therefore, flame treatment in combination with the coating means with a knife coater (described below) appears to be one of the key factors for the surprising success of the present invention as shown below.

Flame treatment is most often used in the treatment of mold plastic parts such as bottles, tubes and automobile parts. However, flame treatment is also widely used to treat membranes, foils, coated cardboard and other substrates. In flame treatment,
The surface of the cardboard passes through the flame produced by the combustion of the super lean mixture of hydrocarbons at a rate sufficient to impart the desired properties. Like corona treatment, flame treatment also includes ionized air vapor that modifies the surface of the cardboard.

An advantage of flame treatment over other surface treatments is that it does not include unwanted treatment of ozone, pinholes, and cardboard backside. In addition, the heat generated by the corona may cause the fibers to dry out more than desired and spread.

The cardboard 14 is optionally fed by a method known in the art to a fountain blade 18 coated with kaolin or other type of viscosity. By addition of TiO ₂ comprising a viscosity to be coated on the cardboard, and white cardboard, reducing the MVTR of the final product by about 50%. Viscosity coatings on products of the present invention typically result in MVTRs less than 1.0. When a viscous coating is applied to the fountain blade 18, it is advantageous to pass the cardboard 14 downstream from the fountain blade 18 (not shown) to a second flame treater to reduce surface organic deposits. . As used herein, "downstream" refers to the location of the disclosed device located further along the path of the cardboard from the origin of the cardboard travel direction. However, the second flame treatment is optional and is not necessary in the present invention.

Therefore, the thick paper 14 is supplied to the preliminary heater 20 and heated. The preheater 20 applies heat to the surface of the cardboard 14, preferably the surface to be coated, to reduce the water content. This allows the cardboard 14 to
Helps to greatly impregnate the coating. The preheating is controlled so as not to remove all or more of the moisture, especially from the opposite side of the cardboard, and the opposite side is later dry enough to pull the moisture again and produce an unwanted curl.

The preheater 20 supplies the cardboard 14 to the coating means through a series of rollers. There are four main types of current coating processes: blade coating, air knife 24 coating, roll coating and rod coating. Blade coating and air knife coating can be performed inside or outside the cardboard machine. Rod coating is usually done "outside" of the cardboard equipment and can be either finish coating or initial coating prior to "outside" coating by blade coating and air knife coating. All four coating methods can be used in the present invention and the Airknife 24 coating has been found to be the most consistent coating.

In air knife coating, the coating mixture is applied by a metal roller and distributed by a thin, flat air jet from a slot in a metal blade that extends across the width of the device. In blade coating, in contrast, the mixture is applied to the surface by rollers to provide a thin level of coating. Excess coating is removed by a thin, flexible metal blade so that it lubricates the surface.

The coating composition used in the present invention is preferably an aqueous dispersion polymer suspension containing 20% -40% solids. A preferred coating composition is a dispersion of a polyester resin, preferably polyethylene terephthalate (PET).

Other suitable water-dispersible polymers are water-soluble or water-dispersed polyester resins as described in US Pat. No. 4,977,191 (Sarusman), which is incorporated herein by reference. In particular, U.S. Pat.
Described a water-soluble or water-dispersed polyester polymer with -50 wt% waste terephthalate polymer, 10-40 wt% at least one glycol, and 5-25 wt% at least one oxyalkylated polyol. is doing.

Other suitable water-dispersible polymers are sulfonated water-soluble or water-dispersed polyester resins as described in US Pat. No. 5,281,630 (Sarusman), which is incorporated herein by reference. Is. In particular, U.S. Pat.
No. 4,968,961 discloses that 20-50% by weight of terephthalate polymer, 10-40% by weight of at least one glycol and 5-25% by weight of at least one are prepared in order to produce a prepolymer resin having hydroxyalkyl functions. A suspension of a sulfonated water-soluble or water-dispersed polyester resin with a reaction product with an oxyalkylated polyol is described. Here, the prepolymer resin reacts with about 0.10 moles to about 0.50 moles of α, β ethylenically unsaturated dicarboxylic acid per 100 g of prepolymer resin and is also terminated by residues of α, β ethylenically unsaturated dicarboxylic acid. The resulting resin is reacted with about 0.5 to about 1.5 moles of sulfite per mole of α, β ethylenically unsaturated dicarboxylic acid to produce a sulfonated terminated resin.

Other water dispersible polymers are the coatings described in US Pat. No. 5,726,277 (Sarusman), which is incorporated herein by reference. In particular,
US Pat. No. 5,726,277 describes a coating composition with the reaction product of at least 50% by weight of waste terephthalate polymer and a mixture of glycols containing oxyalkylated polyols in the presence of glycolytic enzymes. is doing. Here, the reaction product reacts with a difunctional organic acid and the weight ratio of acid to glycol is in the range of 6: 1 to 1: 2.

The above examples are provided as suitable water dispersible polymer coating compositions, but other water dispersible polymers are suitable for use in the present invention. By way of example, but not of limitation, other suitable aqueous dispersion compositions are described in US Pat. No. 4,104,222 (Date et al.), Which is incorporated herein by reference. U.S. Pat. No. 4,104,222 describes mixing a linear polyester resin with a high alcohol / ethylene oxide-containing surfactant, melting the mixture, and melting the resulting melt at 70-90 ° C.
It describes a dispersion obtained by dispersing a melt made by pouring into an aqueous alkanolamine solution with stirring at the temperature of. Here, the alkanolamine is glycerol, monoethanolamine, diethanolamine, triethanolamine, monomethylethanolamine, monoethylethanolamine, diethylethanolamine, propanolamine, butanolamine, and pen. Selected from the group consisting of tanolamine, N-phenylethanolamine, and alkylolamine, wherein the alkanolamine is present in a 0.2-5 wt% aqueous solution, and the high alcohol / ethylene oxide Additive type surfactants are high alcohol ethylene oxide additive products having alkyl groups of at least 8 carbon atoms, alkyl substituted phenols or monoacylated sorbitans, and said surfactants have an HLB value of at least 12. Have.

Similarly, for example, US Pat. No. 4,528,321 (Allen) discloses a water-immiscible liquid dispersion of water-soluble or water-swellable polymer particles, which dispersion is C _4-12 alkylene glycol monoethers produced by reverse phase polymerization in immiscible liquids and their C _1-4
It comprises a nonionic composition selected from alkanoates, C _6-12 polyalkylene monoethers and their C _1-4 alkanoates.

It will be appreciated by those skilled in the art that various coatings have resistance to thermal variability and tensile strength. It is within the prior art to select the proper coating for a given application without undue experimentation.

At the air knife 24, a medium- to high-speed air jet (jet flow) is incident on the cardboard 14 supported by the roll at a measurement angle of about 45 ° with respect to the cardboard. As shown below, this angle changes with changes in process conditions, material quality and certain properties of the coating. The jet cuts the liquid film and removes excess as a liquid, gas or mist. This excess is collected in the blow container system.

The angle (measurement angle) between the center line of the air jet and the radial line passing through the point of incidence has a great influence on the coating surface quality. In general, operating at too large an angle causes the vertical to be oriented in the machine direction; operating at too small an angle causes the crossing of half inch to 1 inch long device lines.

In the air knife 24, the cardboard 14 is excessively coated with a roll in the applicator section. The water in the coating will immediately begin to migrate at the interface between the wet coating and the cardboard 14, causing the coating at this point to be immediately semi-dry or plastic. As the sheet of cardboard passes under the jet of air knife 24, a portion of the fluid coating is removed from the sheet by the air knife. It is in this area that there is a zone at the coating cloth where the coating undergoes a fluid to semi-plastic coating conversion and where air knife cutting occurs. The exact location where the cut occurs varies with the energy content of the air blast. At very high air pressures or velocities from the air knife, much of the air penetrates into the coating and less air remains in the coating on the sheet. Typical air pressures used with air knives are 2 to 9 pounds per square inch.

More importantly, an air knife outer coater. It provides a relatively uniform coating thickness regardless of surface roughness. The air knife 24 minimizes changes in coating thickness, thereby providing a more suitable MVTR for the cardboard 14.

The cardboard 14 goes to a drying means comprising a hood dryer 26 and an IR dryer 30.
The hood dryer 26 may be heated with natural air or the like to dry the coating and, depending on the nature of the coating, at least partially cure the coating. The first roller 22 and the second roller 28 move the cardboard through the dryer. These rollers 22, 28 may be heated by natural air. The hood dryer 26 raises the temperature of the coating to the curing temperature of the coating. The IR dryer 30 continues the drying and curing process started with the hood dryer 26. It is believed that the molecules of the coating begin to crosslink with each other and bind to the fibers of the cardboard during the drying process. In addition, water is removed from the coating leaving solid polyester particles on the cardboard. It is believed that when the water evaporates, the hydroxyl groups of the polymer bind to the cellulose of the cardboard 14 because the polymer is hydrophobic. Once the polyester forms this hydrophobic coating, the M
Following a cold flow that reduces VTR.

The polyester coating begins to crosslink in the dryer, but it does not occur completely. This has the advantage that if the cardboard is subsequently fed to the corrugator, the polymer (eg polyester) will expand due to the heat involved in the corrugating process. As a result, the moisture remaining on the cardboard 14 coated with the coating is “
"" Can be allowed to escape without damaging the membrane coating (which can occur in the prior art). Since the cardboard 14 is heated in the corrugator and then cooled, the polymer coating again forms a barrier. .

Another advantage of the coatings of the present invention is their resistance to wear or chiming. Abrasion of cardboard causes noise in the beverage industry, creating round marks on beverage cans where the coating is abraded. Since the coating of the present invention partially cures prior to such a process, it creates a large resistance to such abrasion.

The cardboard 14 includes a curtain blower 32, an axial fan 34, and a plurality of cooling rolls 36.
Proceed to the cooling means comprising and. The curtain blower 32 may be, for example, a cage blower. The curtain blower 32 irradiates the heat from the coated cardboard 14 with IR.
Blow back into the dryer 30. This prevents excessive heat transfer from the cardboard 14 to the cooling roll 36. The fan 34 and the cooling means 36 continue the coating curing process. The chill rolls 36 cool by pumping the chilled liquid through them, reducing their temperature up to 160 degrees Celsius. The coated cardboard 14 is in a semi-molten state as it exits the dryer. The rapid decrease in temperature due to the cooling means 34, 36, 32 accelerates the coating curing process.

Which of the calender rolls 38 and chill rolls 36 made of a stack of polished cast iron or steel rolls is located at which top is arbitrary. The function of the calendar roll 38 is to increase the surface smoothness and gloss of the cardboard as it passes between rollers (not shown here).

A reel drive 40 is provided downstream of the coater to assist a device drive (not shown) in driving cardboard for winding on a winding roll 42.

Conditions are controlled and varied throughout the process of delivering the desired product. The weight and viscosity of the coating on the cardboard is controlled by controlling the temperature, equipment speed and air knife pressure at various stages of the process. The temperatures of the heating means 20, dryers 26, 30 and cooling means 32, 34, 36 are independently controlled and can be varied to obtain the desired coating properties by one of ordinary skill in the routine experimentation. Device speed can be controlled by controlling the speed of the device drive. The pressure of the air knife 24 is typically controllable by adjusting the discharge pressure and / or the inlet volume of the air knife 24, either by adjusting the flow restrictor or by adjusting the blower speed.

Furthermore, the coating weight is the percentage of solids in the coating solution.
Depends on. The percent solids used will vary with line speed and applied pressure, but polymer dispersions of 20% -40% solids are generally suitable, with 27% -32% solids being preferred.

Once formed, the cardboard product may be collected on roll 42 as shown in FIG. 1, or may be advanced in a continuous process to equipment (not shown) for further processing. This treatment may also include forming into packaging or wrappings for the cardboard product, ie, usually including cutting, scoring, slitting and the like. Also, the resulting cardboard product can be advanced to a corrugator for incorporation into cardboard. Corrugators are typically rolled out from rolls into two or three continuous sheets of paper, pressing a groove into a sheet of corrugated media, applying adhesive at the top of the groove, and joining cardboard sheets to form a cardboard.

In the finished coated product, the adhesion of the coatings to the cardboard is carried out such that they are virtually inseparable, that is to say practically no peeling occurs. The cardboard fibers separate before the coating is stripped from the cardboard. It is indeed surprising to improve the quality of the coatings of the present invention, as the elevated temperatures in the corrugating device, rather than the degradation of the coatings, actually increase the curing of the coatings.

In order to demonstrate the surprising results obtained in relation to the MVTR and strength of the cardboard products produced according to the present invention, the properties of the coated cardboard of the present invention under the various conditions of prior art. Tested to compare with one.

Example I Conventional Waxed Cardboard ("Waxed"); Cardboard with Corrugator Attached Low Density Polyethylene Film (designated "LAMILUX"); M
Cardboard with a two-part acrylic coating sized about 4 pounds per SF (referred to as "SPECTRA COAT"); about 4.0-7 per MSF.
Cardboard with an acrylic-based (acrylic) coating applied at 0 wet pound size (referred to as "MICHELMAN"); PET coated of the present invention (applied at approximately 2.2 dry pounds per MSF) The MVTR, the recycling ability, the printing ability, and the adhesion ability were compared between the cardboard (referred to as "POLYSUPREME"); the polyester of the present invention and the viscosity-coated cardboard (referred to as "POLYSUPREME w / clay"). The results of this comparison are shown below.

[Table 1]

In the above comparisons, MICHELMAN and SPECTRA COAT were attached with a rod or blade coater; LAMILUX was attached as a film; POLYSUPREME was attached with an air knife according to the present invention. MIC
It is speculated that both HELMAN and SPECTRA COAT are comparable to the present invention, and when they are affixed by the present invention, their properties will be similar to POLYSUPREME.

Example II After carding the cardboard according to the invention, it was coated with PET coated flame treated cardboard and PET to demonstrate the dramatic advantages obtained by the combination of air knife cardboard and water dispersed polyester. MV with cardboard without flame treatment
A test for measuring TR was conducted. Flame treatment of cardboard surprisingly reduced MVTR by 60% relative to untreated cardboard. In particular, the non-flame treated coated cardboard exhibited a MVTR of 5.4 and the flame treated cardboard coated with the same coating exhibited a MVTR of 2.2. This is directly due to the flame treatment of the cardboard before coating and the resulting removal of surface fibers and deposits.

These are the advantages of coating in-line. However, the same apparatus and method can be performed off-line, i.e., in the process line even when the time and place where the cardboard is formed is separated.

Many modifications and variations of the present invention will be apparent to those skilled in the art from a consideration of the detailed description with reference to the accompanying drawings. However, such modifications and variations do not depart from the spirit and scope of the invention as defined by the appended claims.

[Brief description of drawings]

1 is a schematic diagram of an apparatus for producing coated cardboard products.

[Explanation of symbols]

  14 cardboard   18 Fountain Blade   20 Spare heater (heating station)   24 Air knife (Coating station)   26 Food dryer (drying station)   28 Second roller   30 IR dryer (drying station)   32 curtain blower   34 axial fan   36 cooling roll   38 Calendar Roll   40 reel drive   100 devices

[Procedure for Amendment] Submission for translation of Article 34 Amendment of Patent Cooperation Treaty

[Submission date] April 25, 2002 (2002.4.25)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Contents of correction]

[Claims]

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Claims (29)

[Claims] 1. A method of forming a polyester film on the surface of a cardboard web by means of a dispersion solution of a polyester polymer, which comprises a series of methods for reducing the water vapor transfer rate of a cardboard and for moving the web into a suitable state. A method for forming a moisture barrier on a cardboard using a coating apparatus having rollers of: (a) flame treating the surface of the cardboard to be coated, wherein the surface deposits and fibers on the surface are substantially (B) heating the cardboard at a temperature sufficient for a sufficient time to reduce the water content to a desired level; and (c) applying a coating roller. Apply the dispersion solution containing the water-dispersed polyester resin to the surface of the cardboard using, and then use an air nap to form a layer of the dispersion solution uniformly over the cardboard. Air jets from the air knife are used to remove excess dispersion on the entire cardboard, and the excess dispersion accumulated by the rollers is removed so that the air jets from the air knives are used to distribute it on the entire cardboard. Distributing a solution; (d) heating the cardboard to a temperature sufficient for curing at least a portion of the polyester and for a sufficient time; (e) curing at least a portion of the above Cooling the cardboard to at least 160 degrees Fahrenheit to reduce the stickiness of the polyester; and allowing the cardboard to be subsequently repulped and capable of easily adhering and printing the cardboard. Temperature to deposit a film of polyester on a cardboard that is at least partially cured to make it recyclable into a product;
A method of controlling the number of times and application of the polyester polymer and dispersion. 2. The flame treatment step (a) comprises passing a flame produced by the combustion of a super lean mixture of hydrocarbons on at least one side of the cardboard. Method. 3. The method of claim 1, wherein the polyester polymer is polyethylene terephthalate. 4. The polyester polymer is (a) 20-50% by weight of waste terephthalate polymer, 10-40% by weight of at least one glycol, and 5-25% by weight of at least one oxyalkylated. A reaction product with a polyol; (b) for producing a prepolymer resin having a hydroxyalkyl function, 20
-50 wt% terephthalate polymer, 10-40 wt% of at least one glycol and 5-25 wt% of at least one oxyalkylated polyol, the prepolymer resin further comprising: The product resin reacted with about 0.10 to about 0.50 mol of α, β ethylenically unsaturated dicarboxylic acid per 100 g of prepolymer resin and terminated with residues of α, β ethylenically unsaturated dicarboxylic acid is
Reacting with about 0.5 to about 1.5 moles of sulfite per mole of α, β ethylenically unsaturated dicarboxylic acid to produce a sulfonated terminal resin; (c) at least 50% by weight of waste terephthalate. A reaction product of a polymer and a glycol containing an oxyalkylated polyol in the presence of a glycolytic enzyme, said reaction product reacting with a difunctional organic acid, the weight ratio of acid to glycol being A process according to claim 1, wherein is selected from the group consisting of reaction products in the range of 6: 1 to 1: 2; 5. The polyester is prepared by mixing (a) a linear polyester resin with a high alcohol / ethylene oxide-containing surfactant, melting the mixture, and melting the resulting melt at 70-90 ° C. A dispersion obtained by dispersing a melt obtained by pouring into an alkanolamine aqueous solution while stirring at a temperature, wherein the alkanolamine is glycerin,
Monoethanolamine, diethanolamine, triethanolamine, monomethylethanolamine, monoethylethanolamine, diethylethanolamine, propanolamine, butanolaminet, pentanolamine, N-phenylethanolamine, The alkanolamine is selected from the group consisting of alkylolamine and is present in an aqueous solution of 0.2 to 5% by weight, and the high alcohol / ethylene oxide added surfactant is at least 8%.
A dispersion of a high alcohol ethylene oxide addition product having an alkyl group of 1 carbon atom, an alkyl substituted phenol or a monoacylated sorbitan and wherein the surfactant has an HLB value of at least 12; (b) a water-soluble or water-swellable water-immiscible liquid dispersion of polymer particles, the dispersion is generated by the reverse-phase polymerization in the water immiscible liquid, and, C _4-12 alkylene glycol mono Ethers, their C _1-4 alkanoates, C _6-12
A process according to claim 1 selected from the group consisting of polyalkylene monoethers and dispersions thereof comprising a nonionic composition selected from C _1-4 alkanoates. 6. The polyester polymer comprises 20% to 40% by weight of solids.
The method of claim 1, wherein 7. The polyester polymer is 27 wt% to 32 wt% solids.
The method according to claim 6, wherein 8. The method of claim 1 comprising the step of thickening the cardboard after step (a) of flame treatment. 9. The method of claim 8, comprising subjecting the cardboard to a second flame treatment after applying a viscosity. 10. The method according to claim 1, wherein the heating step (d) and the cooling step (e) are each performed at a temperature for a time sufficient to at least partially crosslink the polyester polymer. 11. The method of claim 1 including the step of corrugating the coated cardboard. 12. An apparatus for coating cardboard, comprising: a. Flame treatment means; b. Heating means; c. Outer surface coating means for applying a coating of water-dispersed polymer to at least one side of the cardboard; d. Drying means for curing said coating of water-dispersed polymer, e. Cooling means for lowering the temperature of said coating of water-dispersed polymer; 13. The apparatus of claim 12 wherein said flame treatment means comprises means for passing at least one face of said cardboard through a flame produced by combustion of a super lean mixture of hydrocarbons. 14. The apparatus of claim 13 wherein the heating means raises the temperature of the cardboard to a temperature sufficient to remove at least some moisture from the cardboard. 15. The apparatus of claim 14 wherein said outer surface coating means comprises an air knife coater. 16. The device according to claim 15, wherein the water-dispersed polymer is a water-dispersed polyester resin. 17. The water-dispersed polyester resin comprises: a. A reaction product of 20-50% by weight of waste terephthalate polymer, 10-40% by weight of at least one glycol and 5-25% by weight of at least one oxyalkylated polyol; b. For producing a prepolymer resin having a hydroxyalkyl function, 20-
A reaction product of 50% by weight terephthalate polymer, 10-40% by weight at least one glycol and 5-25% by weight at least one oxyalkylated polyol, wherein the prepolymer resin further comprises a prepolymer The product resin reacted with about 0.10 to about 0.50 mol of α, β ethylenically unsaturated dicarboxylic acid per 100 g of polymer resin and terminated with residues of α, β ethylenically unsaturated dicarboxylic acid is sulfonated terminated. Reacting with about 0.5 to about 1.5 moles of sulfite per mole of α, β ethylenically unsaturated dicarboxylic acid to form a resin; c. A reaction product of at least 50% by weight of waste terephthalate polymer and a mixture of glycols containing an oxyalkylated polyol in the presence of a glycolytic enzyme, said reaction product reacting with a difunctional organic acid. The apparatus of claim 16 selected from the group consisting of: a reaction product, wherein the weight ratio of acid to glycol is in the range of 6: 1 to 1: 2. 18. The apparatus according to claim 16, wherein the water-dispersed polyester resin has a solid content of 20 to 40% by weight. 19. The apparatus of claim 16, wherein the water-dispersed polyester resin is 27% to 32% by weight solids. 20. Apparatus according to claim 16 wherein said drying means comprises a hood dryer. 21. The apparatus of claim 20, wherein the drying means further comprises an IR dryer. 22. The apparatus of claim 16, wherein the cooling means comprises a plurality of fans. 23. The apparatus of claim 22, wherein the cooling means further comprises a plurality of chill rolls. 24. The apparatus of claim 23, wherein the cooling means further comprises at least one curtain blower downstream from the drying means. 25. The apparatus of claim 12 including means for imparting viscosity to the cardboard. 26. The apparatus of claim 25, wherein the means for imparting viscosity comprises a fountain blade coater. 27. An apparatus according to claim 26, further comprising a second means for flame treating the cardboard downstream from the fountain blade coater. 28. The apparatus of claim 21, comprising a corrugator. 29. A coated cardboard produced by the method of claim 1.