Improved adhesive having insulative properties.

(54) Title: IMPROVED ADHESIVE HAVING INSULATING PROPERTIES.

(54) Title: IMPROVED ADHESIVE HAVING INSULATIVE PROPERTIES.

(57) Summary

The present invention relates to an improved adhesive composition having increased insulating properties. The adhesive composition having improved insulating properties includes a starch component; an alkaline component; sodium tetraborate; Water; and a plurality of expandable microspheres. Products having improved insulation capabilities and methods for making the products having improved insulation capabilities are also provided. The present adhesive and the products that include the adhesive are environmentally friendly.

(57) Abstract

An improved adhesive composition having increased insulative properties is provided. The adhesive composition having improved insulative properties includes a starch component; an alkaline component; sodium tetraborate; toilet; and a plurality of expandable microspheres. Products having improved insulation capabilities and methods of making the products having improved insulation capabilities are also provided. The present adhesive and products including the adhesive is environmentally friendly.

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PATENT TITLE No. 350366

Owner (s): HENKEL IP & HOLDING GMBH

Address: HenkelstraBe 67, 40589 Düsseldorf, GERMANY

D nomination: IMPROVED ADHESIVE HAVING INSULATING PROPERTIES.

Classification:

CIP:

CPC:

CSetl:

CSet2: CSetS;

C09J103 / 02; C09J7 / 02; CQ9J9 / 00; C09J11 / 00

C09J103 / 02; B31F1 / 20; B31F1 / 2809: C08L2205 / 025; D21H19 / 54;

D21R21 / 54.

C09J103 / 02; C08L3 / 02

C09J103 / 02; C08K3 / 38.

C09J103 / 02; G08KW \ '- .., -, ·

Inventors):

TIANJIAN H ^ ÁNGj I

Number:

MX / a / 2013/002701 '. '"QYES efe September 2011

Country:

US

Validity: Twenty years of September 2010

.............. ................. * .. ...

Núnjero:

61 / 3Q1.642

Expiration Date: September 9, 2031, '> Issue Date: September 5, 2017' ''

The reference patent is based on articles 1⁰ 2nd fretciór »JV» 'e ° fraction III. and 59 of the Industrial Property Law '-'-'- •• -'ή ,. ί # ... .®— —— .. -and, -

Pursuant to Article 33 of the Law, the present patent Wiewta.vigénciit of twenty i from the date of filing of the international application leaves Industnal Property, and will be subject to the current law.

Whoever subscribes to this title does so on the basis of what is provided by fbs ° ®hicul¿s e'fraccíán ^ III and 2 * Ms 2 of the Industrial Property Law (Official Gazette of the Federation <QJ0F ·) 06/27/1991. r ^ rrmAa the% 2% áM994, φ / 10 <§9 & 12/26/1997, 05/17/1999, 01/26/2004, 06/16/2005, 01/25/2006, 05/06/2009 , 06/01 / 2010,18Λ6 / 2010.28 / 06/2010, '27 / 0 ^ / 2012 and 01/04/20121 β ^ κχιΙ ^⁰, 3'4raeóiónV subsection a), 4 ° and 12 ° sections I and III of the Regulations of the Mexican Institute of Industrial Property (D.OF, 14Ί2Μ 999, norm on 01/070602, 1SW7 / 2004, 28/07/2004 and 7/09/2007), articles 1, 3, 4, 5 fraction V subsection a) ^ M6> McaqrNK.ldfcllky 30 áéH? StÉittflÍÓOrgánteC8eÍystiti ^ of Industrial Property (DOF

12/27/1999, amended on 10/10/2002, 07/29 / ^ 0 (^^ 5 ^^^^^^ 20 ^), 14 ^^ 11 ^ 6608 ^ 0¾ ^ AcWdo delegating powers to the Directors them, told to

Deputy Generals. Coordinator, Divisional Directors MilaM Divisional Deputy Directors, Coordinators

Departmental and other subordinates of the Instituto MexiwnoWe láhyÉadtMÍ ^^ 12/5/1999. reformed on 02/04/2000, 07/29/2004,

08/04/2004 and 09/13/2007). 'V

This document is signed with an advanced electronic signature (FIEL), based on articles 7 BIS 2 of the Industrial Property Law; 3 of its Regulations, and 1 section III, 2 section V, 26 BIS and 26 TER of the Agreement establishing the guidelines for the use of the Payment and Electronic Services Portal (PASE) of the Mexican Institute of Industrial Property, in the procedures indicated.

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THE DIVISIONAL DIRECTOR OF PATENTS

NAHANNY CANAL REYES

Original string:

NAHANNY MARISOL CANAL REYES | 00001000000403252793 | Administration Service

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Arena: no 550. Floor 1. Pueblo Santa María Tepepan. Xochimilco, 16020, Mexico City (55) 53340700 www.gob.mx/impi

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MX / 2017/72763

<img file="MX350366B_D0003.tif" />

• 'cm

<img file="MX350366B_D0004.tif" />

INSTITUTO MEXICAN &lt;.

IMPROVED ADHESIVE THAT HAS PROPERTIES ^ HEAR

CROSS REFERENCE TO THE RELATED APPLICATION

This application claims the benefit of US Provisional Patent Application No. 61 / 381,642 filed on September 10, 2010, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an adhesive composition having improved insulating properties. In particular, the invention includes an adhesive composition and method of making an adhesive composition for use in providing insulation to paper products, including corrugated products.

BACKGROUND OF THE INVENTION

Cardboard, which includes corrugated cardboard, is commonly used to provide insulation for various products, including paper cups. Traditionally, corrugated board is first prepared by forming a corrugated member, or middle part, by passing a cellulosic sheet between the corrugating rollers that form a substantially sinusoidal or serpentine cross section in the sheet. The tips of the sinusoidal portion are referred to as

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INDUSTRIAL ΤΚΓ grooves. An adhesive is commonly applied to the tips of the grooves, and a flat non-corrugated cellulosic liner "" © is applied against the adhesive coated grooves of the corrugated elements as the corrugated sheet passes between a corrugating roll and a pressure roll. A resulting paper product that has the corrugation middle on one side and the flat liner on the other side is called a single-sided coil. The single-sided element can be used as found in certain applications as a liner or material or cushion within a container. In some products, the adhesive is also applied to the tips of the single-sided coil grooves and a second backsheet is subsequently applied to the mid-rib portion in a double-sided operation. The second backsheet is exposed to conditions of heat and pressure during its contact with the adhesive. In practice, the most frequently encountered corrugated sheet has two flat sides positioned on each side of the corrugated middle part. Depending on the specific strength desired, a corrugated cardboard sheet can also be provided with a more complex structure, such as two corrugated middle parts and three flat surfaces, two of them outer and one inner separating the two corrugated middle parts.

Starch-based adhesives are widely used

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MEXICAN INSTITUTE i

DE LA fROITEDAU ΓΙ XX „is commonly used in the corrugating process due to its desirable adhesive properties, low cost and ease of preparation. The most important starch corrugation adhesive, commonly referred to as the SteinHall formulation, is an alkaline adhesive that is comprised of raw material, non-gelatinized starch, suspended in an aqueous dispersion of cooked starch. The adhesive is produced by gelatinizing starch in water with sodium hydroxide (caustic soda) to produce a prime mix of a gelatinized or cooked carrier, which is then slowly added to a secondary mixer of plain (non-gelatinized) starch, borax and water to produce the fully formulated adhesive. In conventional corrugating processes, the adhesive is applied to the tips of the middle part of corrugated paper or single-sided cardboard, whereby the application of heat and pressure causes the starch to gelatinize, resulting in an instantaneous increase in viscosity and adhesive bond formation.

Although typical adhesives are sufficient to adhere the various layers of the insulating paper together, these adhesives do not act as insulators by themselves. Thus, in typical situations, at least two layers of paper (the liner and the middle) are required, and in many situations three layers (two liners and the middle) are required. To achieve proper insulation, insulation products

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OF TYPICAL PROPERTY require the middle part to have^W)a&gt; »afa_ £ rud quite high in its wave pattern, - ^ gn-i rj nndn that sq uses more paper in the formation of the middle part. These typical formulations result in a tremendous amount of paper to use for the product, which not only adds cost to production, but is also not environmentally sound.

The present invention seeks to improve insulating papers, through the use of an adhesive composition that adds insulating properties to the product. Also, the adhesive and the products made from it are made from natural components and are environmentally conscious. The present invention provides an environmentally sound insulating adhesive that provides sufficient adhesion to the product with which it is applied.

COMPENDIUM OF THE INVENTION

The present invention relates to a starch composition and method of using the starch composition, which provides increased insulation while maintaining sufficient adhesive strength. The present invention balances the curing properties of the starch composition with the expansion properties of an insulating component to provide a suitable adhesive. In particular, the starch composition is selected to

IMPI .____ ._____, __, ___Ί _. . · 'INSTITUTO MEXICANO. _ have gelatinization temperatures and cu¿erd © u '^TOol $ &gt;&gt; «S ^^ also allow sufficient expansion of the insulating component, to maximize the benefits of both adhesive strength and insulating properties.

In a first embodiment of the present invention, there is provided an adhesive composition having improved insulating properties, including a starch component; an alkaline component; sodium tetraborate; Water; and a plurality of expandable microspheres, where the starch component is selected to allow complete gelatinization of the starch component at a temperature at or greater than the temperature at which the expandable microspheres expand.

Another embodiment of the invention provides a method of preparing a corrugated product having improved insulating properties, including the steps of: providing a substantially flat paper liner having a first side and a second side; providing a paper liner having a plurality of grooves each having a peak and a depression; preparing an adhesive composition having improved insulating properties, including the steps of: combining the starch component with high amylose concentration, an alkaline component, a cross-linking agent, and water to form a starch mixture, and then cooking the mixture starch with high

IMPÍ INSTITUTO MEXICANO amylose concentration to form an nfé ^ ®ritiASe ^^^ BS * ®ⁿCooked; adding an unmodified starch component to the cooked starch mixture; and adding a plurality of expandable microspheres to the cooked starch mixture; applying the adhesive composition to one end of each of the grooves; coupling the peaks of the grooves with a surface of the first side of the flat paper liner to form a composite structure wherein the first paper liner and the second paper liner contact each other at the peaks of the grooves; curing the adhesive composition to the composite structure at a first temperature and a second temperature, wherein the first temperature and the second temperature differ by about -6,666 ° C (20 ° F) to about 4,444 ° C (40 ° F).

Yet another embodiment of the invention provides a method of manufacturing an insulating sheet, including the steps of: providing a substantially flat sheet of paper having a first side and a second side, the first side having a surface with sufficient structure to accommodate an insulating component, prepare an adhesive composition that includes the steps of: combining the high amylose starch component, an alkaline component, a crosslinking agent, and water to form a starch mixture, and then cooking the high amylose starch mixture to form a

IΜ ΡI IN5TITU ΤΟ Μ EX 1CA Ν Ο OF THE PROPERTY cooked starch mixture; add a component^li: e^1ALunmodified de ^ Miaon to the dOdUb starch mixture, 'and' add a plurality of expanded microspheres to the cooked starch mixture; applying the adhesive composition to the first side of the substantially flat sheet of paper to form a sheet with an applied adhesive composition; heating the sheet with an applied adhesive composition to a first temperature sufficient to expand the expandable microspheres; and heating the sheet with an applied adhesive composition to a second temperature sufficient to fully cure the adhesive composition.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 represents the results of tests conducted on various adhesives, showing adhesion when compared to expansion of the microspheres.

Figure 1A is an embodiment of an apparatus for making corrugated cardboard.

Figure 2 is a close-up cross-sectional view of a corrugated cardboard that does not include expandable microspheres.

Figure 3 is a close-up cross-sectional view of a corrugated cardboard including expandable microspheres.

Figure 4 is a cross-sectional view in

<img file="MX350366B_D0005.tif" />

close-up of a corrugated cardboard that includes expandable microspheres.

DETAILED DESCRIPTION OF THE INVENTION

Typical adhesives for use on insulating paper products provide negligible insulating properties, if any, in the final product. These adhesives are generally useful only for adhering a liner (or liners) in the middle, allowing the air gap between the tip of the groove and the liner to achieve insulation. Furthermore, since the adhesive composition only provides adhesion between the tip of the groove and the liner, there is very little space between the tip of the groove and the liner at the point of adhesion. The lack of space between these two elements at the point of adhesion provides very little, if any, added insulation. Since air is the primary insulating medium, the amplitude of the waveform of the middle part must be significant, which requires that the middle part be made from a sheet of paper that is very large. Furthermore, to provide sufficient insulation, such typical products usually use thick layers of paper to form the liner (s), or alternatively use multiple layers of paper to form a liner. As a result, the typical processing of such products is not only an expensive manufacturing process, but also

<img file="MX350366B_D0006.tif" />

Mexican PROPERTY results ^{, N}W '^{TO THE} amount of waste. '' - ~~ ——

The present invention provides an adhesive composition that provides insulating properties to the product in which it is used. The adhesive compositions described herein may be useful in traditional corrugated cardboard products that have a middle portion and either one or two liners. Through the use of the inventive adhesive composition, a greater insulating space can be provided between the tip of the midsection groove and the liner to which it connects at the point of adhesion. In alternative embodiments, the inventive adhesive composition may be useful in forming a cardboard insulation that avoids the need for a middle part, but instead depending on the adhesive composition itself to provide the desired insulation. The adhesive composition described herein is made substantially from natural biodegradable materials, and products made with the inventive adhesive composition require less paper to form. The end result is a more environmentally conscious and less expensive product. Insulating products useful herein include paper products for consumer use, such as hot drink cups, hot food containers, and the like.

The present invention is based on the discovery

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INSTITUTO MEXICANO ¥ &lt;* ^ »^^ £ 8

PROPERTY is that the adhesive composition for use in insulating products may include a plurality of expandable microspheres therein. When these expandable microspheres are allowed to expand in an adhesive composition, they create a foam-like adhesive material, which provides added insulation to the product. For example, when adhesive is applied between the liner and the tip of a mid-part groove, the expanded microspheres can expand, thus providing an insulating space between the tip of the groove and the liner at the point of attachment. This insulated space adds to the insulating properties of the formed product, making possible a middle part that has a smaller amplitude between waves to be used (i.e., less air space requirement), and still provides adequate insulation. The middle layer can have a flatter wave configuration, resulting in less paper usage in the middle layer. Additionally, the added insulation allows the product to use thinner paper and / or single-ply paper liners, resulting in less cost and less waste material.

In a first embodiment, the invention includes an adhesive for preparing an insulating cardboard, such as corrugated or non-corrugated cardboard. Cardboard can be made from any type of paper material, including cellulosic paper material traditionally used in products.

Jí MEXICAN INSTITUTE

OF THE PROPERTY insulators. Desirably, the products of papeff^IAtutitTZcíaos are recyclable materials. '· - · -

The adhesive composition can be made from any number of materials. Desirably, the adhesive composition includes water, a starch component, a crosslinking component, an alkaline component, and a plurality of expandable microspheres. The adhesive composition can further include one or more humectants, preservatives, or fillers. Other materials that do not adversely affect the adhesive and the insulating properties of the adhesive composition can be used as desired.

The adhesive composition can include any polar solvent, particularly water, in the formulation. In a desired embodiment, prior to hardening (or gelatinizing) the composition, the adhesive composition includes the polar solvent in an amount of from about 40% to about 75% by weight of the adhesive composition prior to hardening of the composition, and more desirably from about 50% to about 70% by weight of the composition prior to setting the composition.

The adhesive composition includes a starch component. The starch component may be present in the adhesive composition in any amount, and is desirably present in an amount from about 20% to about 40% by weight of the adhesive composition.

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MEXICAN INSTITUTE

OF INDUSTRIAL PROPERTY prior to setting of the composition, and more desirably from about 25% to about 35% by weight of the adhesive composition prior to setting of the composition. The starch component can include any desired starch materials, particularly starch materials derived from natural sources, including, for example, corn. In some embodiments, the starch component can include starch that has a highly branched composition. For example, the starch component can include unmodified starch or pearl starch. As used herein, the term "unmodified starch" refers to a starch composition that has less than 25% amylose content. The unmodified starch can be used in any form, and is preferably used in the form of a powder or granulate having a diameter of about 20 microns. In other embodiments, the starch component can include a cooked starch, also referred to as a carrier starch. Cooked starch can have a higher viscosity than unmodified starch.

In still other embodiments the starch component may include a starch material having a composition with a higher concentration of straight chain materials. Such components may include a high amylose starch material including that sold by Henkel.

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Corporation under »u &lt;Ti®I

<img file="MX350366B_D0007.tif" />

commercial Optamyl®. As pn —- L- ^ prpgpnte is used, nn starch having a high amylose content (referred to as high amylose starch) includes at least 50% amylose content. In some embodiments, a high amylose concentration starch may have between about 25% to about 50% amylose, and more desirably between about 35% and 50% amylose concentration. As will be explained below, in one embodiment, the use of a high amylose concentration starch material in combination with an unmodified starch material can be beneficial for the expansion of microspheres in the adhesive composition. The combination of high amylose starch and unmodified starch results in a starch component that has a higher moisture content and a higher final set (or cure) temperature.

In embodiments where the starch component includes a combination of materials, the starch component includes a mixture of unmodified starch and at least one of the cooked starch or a high amylose starch. Desirably, the starch component includes a mixture of unmodified starch and high amylose starch. The starch component Mexican institute

DE The unmodified INDUSTRIAL PROPERTY &lt;7 ^ - 1¾ can be from about 60% to about 90% by weight of the starch component. In preferred embodiments, the unmodified starch component and the high amylose starch component are present in a ratio of from about 5: 1 to about 3: 1.

The adhesive composition can include one or more alkaline components. The alkaline component can be present in an amount of from about 0.5% to about 1.5% by weight of the adhesive composition prior to curing of the composition. The alkaline component can include any component that is alkaline in nature. In particular embodiments, the alkaline component includes sodium hydroxide, however, any desired alkaline component can be used as desired.

The adhesive composition can include one or more crosslinking components. Crosslinking agents useful in the present invention may include, for example, sodium tetraborate (also referred to as Borax). Crosslinking agents may be present in the invention in an amount from about 0.10% to about 0.20% by weight of the adhesive composition prior to curing of the composition.

The adhesive composition can include any optional components, including humectants,

<img file="MX350366B_D0008.tif" />

conservatives, or charges. Humectants useful in the present invention help maintain the stability and viscosity of the composition, and may include, for example, glycerol, glycerin, urea, propylene glycol, glyceryl triacetate, sugars and sugar polyols such as sorbitol, xylitol, maltitol, and polymeric polyols such as polydextrose, natural extracts such as quillaia or lactic acid, or any other desired composition that has wetting properties. Humectants may be useful in the present invention in an amount of from about 0.1% to about 15% by weight of the adhesive composition prior to curing of the composition. Preservatives may be useful in the present invention, and include preservatives such as 1,2-benzisothiazolin-3-one. Preservatives can be used in the amount of from about 0.05% to about 0.20% by weight of the adhesive composition prior to curing of the composition. Any desirable fillers can be used as is known in the art.

The adhesive composition includes a plurality of expandable microspheres. The expandable microspheres useful in the present invention must be capable of expanding in size in the presence of heat and / or radiation energy (including, for example, microwave, infrared, radio frequency and / or ultrasonic energy). Microspheres useful in

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CE INDUSTRIAL PROPERTY ¡€&gt; ”* ^ 8« ^ The present invention includes, for example, heat-expandable polymeric microspheres, including those having a hydrocarbon core and a polyacrylonitrile shell (such as those sold under the trade name Dualite®) and other similar microspheres (such as those sold under the trade name Expancel®). The expandable microspheres can be any unexpanded size, including from about 12 microns to about 30 microns in diameter. In the presence of heat, the expandable microspheres of the present invention may be capable of increasing in diameter by about 3 times to about 10 times. That is, the diameter of the expandable microspheres can be expandable from about 300% of the starting diameter to about 1000% of the starting material, and more desirably, the diameter of the expandable microspheres can be expandable from about 350% to about 600% of the starting diameter. With the expansion of the microspheres in the adhesive composition, the adhesive composition becomes a foam-like material, which has improved insulation properties. It may be desirable, as will be explained below, that the expansion of the microspheres is carried out in a partially gelatinized adhesive composition.

Expandable microspheres have a particular temperature at which they begin to expand 'and a second temperature at which they reach their maximum expansion' Desirably, the temperature at which these microspheres begin to expand (Texp) is approximately 82.222 ° C ( 180 ° F) to about 98,889 ° C (210 ° F), and more desirably from about 87,778 ° C (190 ° F) to about 97,778 ° C (208 ° F). The temperature at which the microspheres have reached maximum expansion (Tmax) is desirably from about 121.11 ° C (250 ° F) to about 140.56 ° C (285 ° F), and more desirably from about 125 ° C (257 ° F) to approximately 135 ° C (275 ° F). Of course, different grades of microspheres have different Texp and Tmax. For example, one particularly useful microsphere has a Texp of approximately 97,778 ° C (208 ° F) and a Tmax of approximately 135 ° C (275 ° F), while another useful microsphere has a Texp of approximately 87,778 ° C (190 ° F). F) and a Tmax of approximately 130 ° C (266 ° F). Although any particular grade of microspheres can be used in the present invention, the process must be slightly modified to account for the Texp and Tmax of the microspheres.

Although the choice of the particular microspheres and their respective Texp and Tmax is not critical to the invention, the processing temperatures can be modified depending on these temperatures. In most of the

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MEXICAN WiSTirUTO

FOR PROPERTY applications, it is desirable that Tmax for myo ^ d ^ fercte ^ be at a temperature that is equal to or lower than the full hardening (or cured) temperature of the starch adhesive composition. As can be appreciated by those skilled in the art, the inventive adhesive composition includes a plurality of unexpanded microspheres in a fluid starch-based adhesive composition. Before the adhesive composition is fully cured or cured, these microspheres are able to move within the composition and are capable of expanding. Once the adhesive composition sets, however, the microspheres are substantially locked in place, making expansion thereof difficult, if not impossible. For this reason, it is useful that the maximum expansion temperature of the microspheres (Tmax) is equal to or lower than the complete set temperature of the adhesive composition.

Of course, it can be noted that the starch-based adhesive composition will begin to harden, or gelatinize, at a temperature lower than the full cure temperature. In some embodiments, the initial setting temperature of the starch composition can be from about 138 ° F (58,889 ° C) to about

68,889 ° C (156 ° F). Although the starch adhesive begins to gelatinize at this temperature, the adhesive composition can

<img file="MX350366B_D0009.tif" />

IMPI

MEXICAN INSTITUTE

EU INDUSTRIAL PROPERTY will still have a high moisture content and will be substantially fluid. The temperature at which the starch adhesive composition fully hardens is equal to or greater than Tmax of the expandable microspheres, however, the temperature at which the starch adhesive composition fully hardens can be between the Texp and Tmax of the microspheres. .

It may be desirable that the maximum expansion temperature of the microspheres (Tmax) and the final set temperature of the adhesive composition differ by about -6,666 ° C (20 ° F) to about 4,444 ° C (40 ° F), and from most desirably about -1,111 ° C (30 ° F). This difference enables the expandable microspheres to expand and the adhesive to properly cure. Desirably, the temperature at which the adhesive begins to gelatinize may be from about -6,666 ° C (20 ° F) to about 4,444 ° C (40 ° F) lower than the Texp of the microspheres, and most desirably approximately -1,111 ° C (30 ° F) lower than the Texp of the microspheres, and the temperature at which the adhesive fully hardens can be approximately -6,666 ° C (20 ° F) to approximately 4,444 ° C (40 ° F) higher than Tmax of the microspheres, and desirably about -1,111 ° C (30 ° F) greater than the Tmax of the microspheres.

. IMPIOS r Mexican institute 'LE LA FROPIEUAb V \ κμΆ,¹ jf, INDUSTRIAL

In a particularly desirable embodiment of products of manufacture, the adhesive composition can be applied to the surface (or surfaces) of a product and subjected to sufficient heat to initiate gelatinization of the adhesive. Starting the gelatinization of the adhesive can help keep the adhesive and microspheres in place, but will allow the microspheres the freedom to expand. The heat can then be raised to a temperature sufficient to expand the microspheres. Finally, and the heat can be raised back to a temperature sufficient to fully harden the adhesive composition. Heat can be applied by any desired method, including in an oven or through the use of heated rollers. It should be noted that the various phases (initial gelatinization, expansion of the microspheres, and complete set of the adhesive) can be accomplished by radiation energy, either as a replacement for or in addition to direct heat. That is, for example, the various steps can be achieved by the use of microwave or radio frequency radiation, for example. Additionally, the process can include any combination of the application of heat and the application of radiation. For example, initial gelatinization of the adhesive composition can be achieved through direct heat, while expansion of the microspheres can be achieved through the application of radiation energy.

IMPI 'INSTITUTO MEX 1CANO ·' *&gt; /!

Of the property

INDUSTRIAL

In some embodiments, the starch component of the adhesive composition includes a blend of unmodified starch and high amylose starch. This combination of starches results in a composition that has a higher moisture content, and thus a higher final setting temperature. Although the initial gelatinization temperature of the adhesive can remain around the same temperature, the final set temperature can be higher than with just unmodified starch. It has been discovered that, by increasing the setting temperature of the adhesive composition, a larger temperature window can be provided in which to expand the microspheres. Other additives can be included in the composition to increase the setting temperature of the adhesive when desired.

The adhesive composition includes a plurality of unexpanded expanded microspheres. Depending on the particular expandable microspheres used in the composition, the desired amount of microspheres in the composition can be varied. It has been found that if the adhesive composition includes too high a concentration of expandable microspheres, the adhesion with expanding microspheres will be insufficient. However, if there is too low a concentration of expanded microspheres, the resulting adhesive expansion and consequently insulation will be insufficient. INSTITUTE M £ Xi (insufficient. Consideration of the loading level and expansion ratio, as well as expansion ratio and temperature at loading level should be taken into account when determining the optimal concentration of expanded microspheres in the composition. If the expansion ratio of the microspheres is lower, it may have a higher concentration in the adhesive composition and conversely, if the expansion ratio of the microspheres is higher, it may be a lower concentration in the adhesive composition.

In preferred embodiments, it is desirable that the expandable microspheres be present in the adhesive composition in an amount of from about 0.5% to about 5.0% by weight of the adhesive composition prior to curing of the composition, and more desirably from about 1.0% to about 2.0% by weight of the adhesive composition before the composition hardens, and most desirably about 1.2% by weight of the adhesive composition prior to curing of the composition. For an embodiment that includes expandable microspheres having a diameter expansion ratio of about 370% at Tmax, the microspheres may be present in an amount of about 1.5% to about 2.0% by weight of the

IMPIO ^ a Mexican institute

OF THE PROPERTY C ______J 'ji ___ · _ _ „.___ _i _ ί ___i _ ·· INDUSTRIAL adhesive composition before hardening of the composition. For a modality that irTCTUyé 'TM.Crüéyfti.L'dy expands having a diameter expansion ratio of about 470% at Tmax, the microspheres can be present in an amount of about 1.0% to about 1.5% by weight of the composition adhesive before the composition hardens. In systems where lower heating capacities exist, it may be desirable to include a higher concentration of expandable microspheres, such as up to 4% by weight of the adhesive composition prior to setting the composition. The expansion ratio of the expandable microspheres and the charge level of the microspheres will be related to each other. As shown in Figure 1, several different grades of expanded microspheres have been tested, demonstrating the concentration of microspheres in various adhesive compositions that fall within the danger zone (loss of adhesion) and the safe zone (good adhesion). Desirably, the concentration of the microspheres in the adhesive composition should fall within these two zones. This balances expansion, and thus insulation, with adhesion of the resulting foam-like adhesive.

The present invention provides a method of preparing an adhesive composition having properties of

<img file="MX350366B_D0010.tif" />

improved insulation. The method includes first combining a starch component, alkaline component, a cross-linking agent, polar solvent, and optional humectants, preservatives, or fillers to form a starch mixture. Once the starch mixture is formed, it can be partially gelatinized to form a gelatinized starch mixture, and then the plurality of expandable microspheres can be added to the gelatinized starch mixture. If desired, the plurality of expandable microspheres can be added to the starch mixture prior to starting gelatinization. In some embodiments, the starch component may include a combination of unmodified starch and high amylose starch. In such embodiments, it may be preferable to combine the high amylose starch component, the alkaline component, a crosslinking agent, polar solvent, and optional humectants, preservatives, and fillers, when gelatinizing these mixtures, and then separately adding the component. unmodified starch. Once this mixing is achieved, the plurality of expandable microspheres can be added.

In other embodiments, the present invention provides a kit for providing an adhesive composition having improved insulation properties. In this embodiment the kit includes two parts, a first part and a second part, which are desirably stored in separate containers. The first part includes a starch adhesive component, which includes the starch component, alkaline component, a cross-linking agent, polar solvent, and optional humectants, preservatives, or fillers. The first part can be partially gelatinized if desired, providing increased viscosity to the first part. The second component includes a plurality of expandable microspheres. The second part can include the microspheres in any form, such as dry powder, solution, or any desired form. The kit may further include a means for combining the two parts together to form the adhesive composition that has improved insulation properties, such as a separate container into which each of the first and second parts can be fed. If desired, the kit may further include instructions for use in preparing the adhesive composition.

The present invention further relates to an insulated corrugated cardboard. Any known process for forming corrugated cardboard can be used, and Figure 1A depicts one embodiment of an assembly useful in forming corrugated cardboard. Desirably, the board is made of paper that has a reduced thickness when compared to traditional insulating corrugated boards. Any kind of paper

IMPI Mexican institute, ....,. . . . , can be used in the invention, for example,^lé ^^Tj ^ pei * -ptteae have a thickness of about 0.091om (0x0036 inch-dear) · - · to about 0.0132cm (0.0052 inch) in thickness.

Furthermore, it is desirable to use paper of a lower weight than that traditionally used in insulating products. Traditional insulation products generally use number 33 paper for the various paper components. It is desirable to use paper that is of a lower weight than No. 23 paper, and more desirably, it is desirable to use No. 18 paper for the various components of the corrugated board. That is, the various components (including the liner (s) and the middle portion) desirably include paper that is known as number 18 paper (0.0098 cm (0.0036 inch) thick, density of about 67.72g / m2).

Insulated corrugated paper can be single-sided or double-sided. Single-sided corrugated papers include a plain paper liner, which is a substantially flat paper liner having a first side and a second side, and a middle portion, which is a paper liner having a first side and a second side. second side that has been formed in a sine wave configuration having a plurality of grooves on each side. In this embodiment, the first side of the paper liner is secured to the tip of the grooves on the first side of the middle. A carton

IMPI ΙΝαΤΙΤυΤΟ MEXICAN DE LA PROPERTY double-sided corrugated also includes a s'é'g'tJNdo reíro de papel, which is a paper lining susfcanoialmonto -piaftO-qiae has a first and a second side, where the first side of the second paper liner is secured to the tips of the grooves on the second side of the middle. Although the following description of board and the methods for making such boards is generally directed to single-sided boards, it will be understood that the invention further relates to double-sided boards, which can be achieved by including a second liner either at the time. processing of the first liner or after the first liner has been adhered.

The inventive corrugated board of the present invention includes the inventive adhesive described above. The inventive adhesive, which includes the starch component, alkaline component, a crosslinking agent, polar solvent, plurality of expandable microspheres, and optional humectants, preservatives, or fillers is applied to the tip of the midsection grooves. In one embodiment of the invention that includes a high amylose starch component and the unmodified starch component, the high amylose starch component, an alkaline component, a crosslinking agent, and water are combined to form a starch mixture, and then the high amylose starch mixture is cooked to form a mixture of

IMPI. , Z MEXICAN INSTiTOTE J&gt;

cooked starch. Then, a modifying component can be added to the cooked starch mixture, and a plurality of expandable microspheres are added to the cooked starch mixture. Alternatively, the adhesive components can simply be added together.

If a single-sided corrugated board is desired, the adhesive composition is applied to the tip of the grooves on either side of the middle, and the first side of a paper liner is applied thereto. If desired, the adhesive composition is partially gelatinized. The expanded microspheres are allowed to expand and then the adhesive composition is set in place. The corrugated cardboard thus resulting has an insulating space between the surface of the paper liner and the tips of the middle grooves at the adhesion tip. Corrugated board desirably has an insulating gap between the paper liner and the tips of the grooves at the point of adhesion in the amount of approximately 0.0254cm (0.01 inch). It should of course be understood that the particular increase in the distance between the tips of the grooves and the liner is not critical, and that a small increase in the distance can generate a significant amount of added insulation. In desired embodiments, the space between the tip of the groove and the release liner of the present invention may be greater than the distance between the tip of the groove.

<img file="MX350366B_D0011.tif" />

without expanded materials. At the same time the desired increased distance between the tip of the groove and the liner should not be greater than when it is damaging to the bond strength between the two.

If a double-sided corrugated board is desired, the adhesive composition is applied to the tips of the grooves on the second side of the middle part, and a second paper liner is applied thereto. Similarly, the adhesive is partially gelatinized, the expandable microspheres are allowed to expand, and then the adhesive composition hardens in place. The corrugated cardboard thus resulting has an insulating space between the surface of the paper liner and the tips of the grooves in the middle part. The corrugated board desirably has an insulating space between the paper liner and the tips of the grooves at the point of adhesion in an amount that is greater than the space traditionally seen with conventional adhesives. In one embodiment, the increase in space between the two that is generated by the expanded microspheres is approximately 0.00254 cm (0.001 inches).

The present invention is not limited to single or double sided corrugated cardboard and can be used in a number of applications. Other applications in which the

ΙΜΡΙίν&gt; ^ .________. · Z. . z. . , ·,,. The Mexican invention is useful to include higher viscosity double back formulations, higher viscosity coater applications, lower viscosity coater applications, and the like.

It is particularly preferred that the middle layer has a reduced width when compared to traditional corrugated boards. Through the use of the present invention, there is an insulation gap between the tip of the groove and the liner surface at the point of contact, which provides added insulation. This added insulation reduces the need when there is a lot of air space between the grooves on the second middle side and the paper liner. In a preferred embodiment, the width of the mid-portion is approximately 0.1016 cm (0.04 inches) as measured from the tip of the adjacent grooves, whereas traditional media have a groove wavelength of 0.01600 cm (0.063 inches) to approximately 0.3403cm (0.134 inches). Thus, in one embodiment, the invention provides a corrugated board having a middle portion having a reduced wavelength, wherein the reduced wavelength is from about 0.508cm (0.02 inches) to about 0.2286cm (0.09 inches). smaller than traditional corrugated cardboard.

It has been discovered that through the use of

IMPIOS,. ,, υι ^ τι, τυτο mwca ^^^ present adhesive composition, and the reduccioJQpKfflfeALla (&gt; aittjMJiítad^{c J} INDUSTRIAL middle part reduces the overall amount of paper used in corrugated board by approximately 20% when compared to traditional corrugated board. Furthermore, the added insulation makes it possible for insulation products to be formed with thinner paper liners and middle parts, again resulting in reduced cost and also reduced waste.

The present invention further provides a method of forming a corrugated board having improved insulation properties. As explained above, it has been discovered that the adhesive composition must balance the setting temperature of the starch-based adhesive with the expansion temperature of the expandable microspheres used herein. In the inventive method, a substantially flat first paper liner is provided having a first and a second side. The first paper liner has a thickness of approximately paper which can be approximately 0.0091cm (0.0036 inches) to approximately 0.0132cm (0.0052 inches) in thickness, which is thinner than traditional paper liners used in cartons. corrugated boards, which are traditionally about 0.0157cm (0.0062 inch) thick. A second paper liner is provided which has a first and second side, which is formed in a middle part and which has a sine wave that

<img file="MX350366B_D0012.tif" />

grooves on each of the first and second sides. Ta pa.rt · ^ mean desirably has an amplitude of approximately 0.1016cm (0.04 inches) when measured from the tip of the adjacent groove, and a wavelength of approximately 0.0330cm (0.13 inches).

An adhesive composition is prepared. The adhesive composition can be prepared immediately before forming the corrugated board or it can be prepared in advance and stored until needed. The adhesive composition is prepared by combining a starch component, alkaline component, a crosslinking agent, polar solvent, and optional humectants, preservatives, or fillers to form a starch mixture, and partially gelatinizing the starch mixture to form a gelatinized mixture. . A plurality of expandable microspheres are added to the gelatinized mixture, forming the adhesive composition. If desired the expandable microspheres can be added to the starch mixture prior to partially gelatinizing the mixture.

As explained above, the starch component of the adhesive composition can include unmodified starch, cooked starch, high amylose starch, and combinations thereof. The various components of the adhesive composition may be present in the adhesive composition in the amounts described above.

IMPIOS INJTI i UTO MEXICANO .Λ. . .^{OF THE} it-ohedad, anterior. In preferred modalities, the compose&gt; tBJ^TOfrom^TO* «ÑHEraOn includes a mixture of starch without inndifimr and a-im-ίΗήη with a high concentration of amylose. It is particularly preferred that the maximum expansion temperature of the microspheres is a temperature that is lower than the final setting temperature of the adhesive composition, for the reasons stated above. However, the temperature at which the adhesive composition begins to gel or harden may be lower than the expansion temperature of the expandable microspheres. If desired, additives or other components can be added to the adhesive composition to raise the setting temperature thereof. It is desirable that the full cure temperature of the adhesive is at least as high as the Tmax of the expandable microspheres and in particular it is desirable that the full cure temperature of the adhesive be at least -1,111 ° C (30 ° F) higher than Tmax of the expanded microspheres.

In the method of forming the corrugated board, a predetermined amount of the adhesive composition is applied to the tips of the grooves on the first side of the middle part. Desirably, the adhesive composition is applied in a relatively thin layer, the layer having a thickness of from about 0.1270 cm (0.05 inches) to about 0.1778 cm (0.07 inches). The adhesive composition can be applied in

MEXICAN INSTITUTE /

OF THE PROPERTY 2¹'

INDUSTRIAL the presence of heat and / or pressure. In one embodiment, the adhesive composition can be applied under a pressure of about 30 bar and when the middle portion is heated to a temperature of about 1480.89 ° C (300 ° F).

After the adhesive composition has been applied to the tips of the grooves on the first side of the middle portion, the tips of the grooves connect with the first side of the first paper liner. It is desirable that the contact is made under light pressure, so that the middle part and the paper liner are effectively joined, but excessive pressure will be avoided (to avoid removing the adhesive from the contact point). At this point, an uncured corrugated product is formed, where the paper liner and the middle portion are secured to each other by the adhesive, although the adhesive has not set. If desired, the uncured corrugated product can be exposed to heat and / or radiation energy sufficient to initiate gelatinization of the adhesive, but insufficient to expand the plurality of expandable microspheres. Gelatinization of the adhesive can be helpful in holding the various components of the product in place until final cure is established.

The uncured corrugated product is then exposed to heat (including a heated oven or roller contact path) and / or radiation energy (including, for example, microwave, infrared, rá ^ 'fo'ftecuSTTóia, or ultrasonic energy) to expand the pluraliti'cTd 05 ΤΠΤ5ΤΟ55Τ5Τ35Ύ 'In one embodiment, the uncured corrugated product is exposed to heat or temperature sufficient to expand at least most of the microspheres at the tip of a groove, although the temperature is insufficient to fully cure the adhesive composition. In another embodiment, the uncured corrugated product is exposed to microwave or infrared energy sufficient to expand at least a majority of the expandable microspheres, although at an energy level that will not fully cure the adhesive composition. The resulting product is an uncured corrugated product having expanded microspheres.

As can be understood, at this point in the process, the microspheres at any given groove tip have expanded to form a foam-like adhesive composition, generating increased space between the groove tip and the paper liner. Thus, during the manufacturing process, it is important that the adhesive composition is allowed to expand and separate the first paper liner and the middle portion. That is, any pressure that the first paper liner and the middle part hold should not be so great to prohibit the expansion of the adhesive and thus the separation of the paper liner and the middle part. If the pressure is too great, the adhesive may

INSTITUTO MEXICANO DE LA PROPIEDAD expand to the side, that is, in the air space between the middle part and the paper lining. In addition, any thermal and / or radiation energy applied to the product must not be so great that it fully hardens the adhesive composition, allowing the microspheres to expand. It is desirable that the expanded adhesive composition is located at each of the tips of the groove at the point of contact with the liner, thus providing an insulating space between the first paper liner and the middle portion at the contact site.

After expansion of the microspheres, the uncured corrugated product having expanded spheres can then be exposed to thermal and / or radiation energy (including microwave or infrared energy) sufficient to harden or fully cure the adhesive composition. The result is a corrugated paper that has improved insulating properties .

The method described above provides a single-sided corrugated board. However, the above method can also be used to provide a double-sided corrugated board. In addition to the above steps, a second substantially flat paper liner may be provided. The second liner can be applied to the second side of the middle at the same time as the first liner is applied to the first side of the middle, or the second liner can be applied to the second

<img file="MX350366B_D0013.tif" />

half after the first liner adheres S the ¹ pai Le—- · media. It may be desirable for the second liner to be applied to the second side of the midsection after the first liner has fully adhered to the midsection. The processing and hardening step as described above can be repeated with the second liner to provide a double-sided corrugated board.

In some embodiments, it may be desirable to form supports of expanded adhesive material (also referred to as fillets) along the tip side of the grooves, between the groove and the liner. For example, as can be seen in Figure 2, which is a close-up cross-sectional view of adhered corrugated cardboard without expanding microspheres, there is little material on the sides of the groove tip. Figures 3-4, however, are close-up cross-sectional views of a corrugated board adhered with expandable microspheres, which represent the presence of the expanded adhesive composition on the side of the groove. These supports can aid in the strength of the bond between the midsection and the liner, and therefore can be desirably generated. However, it is of course understood that the formation of supports along the grooves is not required and may not be desired in some embodiments.

IMPI

MEXICAN INSTITUTE

OF THE PROPERTY

In an alternative embodiment, there is an insulating paper product that does not have enough radiation, and a method of forming an insulating paper product that has no middle part. As can be appreciated by those of skill in the art, conventional insulating corrugated boards require the presence of the middle part, which is a sine wave configuration to provide an air gap between the middle part and the paper liner (s). The air cavity provides the necessary insulation. Since the middle layer constitutes more than half the role of the corrugated product in a single-sided design, it may be particularly desirable that the middle layer be omitted. Removing the middle part can result in a product that uses less than half the traditionally required paper which can significantly reduce the cost associated with the product and also reduce the waste generated by more than half. However, until now, it has been difficult to achieve a product that has the necessary insulation without including the middle layer.

The present invention provides an insulating product that does not include a middle layer. The adhesive composition of the present invention has been found to be capable of providing the necessary insulation required in insulating products. In this mode,

IΜ ΡI

INSTITUTO MEXICANO i ·.

OF PROPERTY t industrial provides an insulating sheet that includes a substantially flat paper liner having a first side and a second side. The first side of the paper liner includes a plurality of expandable microspheres secured thereto in an adhesive composition, where the plurality of expandable microspheres have been expanded and the adhesive composition has been cured or cured. Thus, the product includes a paper liner having a foam-like composition adhered to the first side thereof. Expandable microspheres include those described above, and the adhesive composition includes the composition described above, which includes a starch component, alkaline component, crosslinking agent, polar solvent, and optional humectants, preservatives, or fillers. As explained above, the starch component of the adhesive composition can include unmodified starch, cooked starch, high amylose starch, and combinations thereof.

The adhesive composition of the insulating product can be applied to the first surface of the paper liner in any desired configuration, including a series of dot, stripe, wave, checkerboard patterns, any general polyhedron shape having substantially flat bases, and combinations thereof.

Furthermore, the adhesive composition can be applied the first time

INSTITUTO MEXICANO surface of a series of cylinders. Gesture⁶The adhesive composition can be applied to the first surface as a substantially flat sheet of adhesive that covers the entire first surface or covers a portion of the first surface. Optionally, a second paper liner can be applied to the top surface of the adhesive composition, forming an interleaving configuration of: first paper liner - expanded microsphere adhesive - second paper liner.

A method of forming an insulating sheet is also provided. In this method, a substantially flat paper liner is first provided having a first surface and a second surface. An adhesive composition is prepared. The adhesive composition can be prepared immediately prior to forming the insulation sheet, or it can be made in advance and stored until needed. The adhesive composition is prepared by combining the materials described above, including a starch component, alkaline component, crosslinking agent, polar solvent, and optional humectants, preservatives, or fillers to form a starch mixture, and gelatinize the starch mixture. to form a gelatinized mixture. In embodiments where the starch component includes a combination of unmodified starch and a high amylose starch component,

<img file="MX350366B_D0014.tif" />

JMPI INSTITUTO MEXICANO DE LA rPOPIWAi · INDUSTRIAL it may be desirable to partially gelatinize the starch component with high concentration of amylose, alkaline component, cross-linking agent, polar solvent, and optional humectants, preservatives and fillers before adding the unmodified starch component. A plurality of expandable microspheres are added to the partially gelatinized mixture, forming the adhesive composition. If desired, the expandable microspheres can be added to the starch mixture prior to partially gelatinizing the mixture.

As explained above, the starch component of the adhesive composition can include unmodified starch, cooked starch, high amylose starch, and combinations thereof. The starch component desirably includes the mixture of unmodified starch and high amylose starch, as discussed above. The various components of the adhesive composition may be present in the adhesive composition in the amounts described above. It is particularly preferred that the maximum expansion temperature of the microspheres (Tmax) is a temperature equal to or lower than the complete curing temperature of the adhesive composition. If desired, additives or other components can be added to the adhesive composition to raise the temperature of

<img file="MX350366B_D0015.tif" />

hardening of it. It is desirable that the complete cure temperature of the adhesive be at least as high as the Tmax of the expanded microspheres, and particularly desirable that the complete cure temperature of the adhesive be at least -1,111 ° C (30 ° F) greater than the Tmax. of the expanded microspheres.

In the method of forming the insulating sheet, a predetermined amount of the adhesive composition is applied to the first surface of the paper liner. The adhesive composition can be applied in any desired configuration, including, for example, in a series of patterns of dots, stripes, waves, checkerboard, a series of polyhedra, and combinations thereof. Furthermore, the adhesive composition can be applied to the first surface in a series of cylinders. Furthermore, if desired, the adhesive composition can be applied to the first side as a substantially flat sheet of adhesive, covering all or part of the first side of the paper liner. The adhesive composition can be applied in any desired thickness, and is desirably applied in a thickness of about 0.1016 cm (0.04 inches). In embodiments where the composition is applied in the form of a cylinder, it may be desirable for the height of each cylinder to be approximately the same as the diameter of each cylinder. The cylinders can be applied to the first surface in any configuration, desirably each

WICKED.

MEXICAN INSTITUTE

OF THE PROPERTY

INDUSTRIAL cylinder is separated by a substantially equal distance from each other from the cylinder. It is particularly desirable that the 1T spacing between adjacent cylinders is approximately twice the height of the cylinders. The adhesive composition can be applied in the presence of heat, if desired, however it is important that the heat on application is not so high as to fully cure the adhesive composition.

After the adhesive composition has been applied to the first side of the paper liner, the paper liner with wet adhesive thereon can be exposed to thermal energy and / or radiation to begin curing of the adhesive composition. The adhesive composition thereof locks the components, including the plurality of microspheres, in place and adhering them to the surface of the paper liner. It may be desirable to only partially cure the adhesive composition, thus providing a composition that locks the components and keeps them adhered to the surface of the paper liner, but does not fully cure. As explained above, only partial curing of the adhesive composition (ie, leaving the greatest amount of wetting in the adhesive, such as at least 10% moisture content) allows the expandable microspheres to expand.

After the adhesive hardens, the liner

<img file="MX350366B_D0016.tif" />

IMPI

MEXICAN INSTITUTE

FROM INDUSTRIAL PROPERTY paper is then exposed to sufficient thermal and / or radiation energy to expand the plurality of microspheres. In one embodiment, the paper backing with wet adhesive thereon is exposed to heat at a temperature sufficient to expand at least a majority of the microspheres. In another embodiment, the paper backing with wet adhesive thereon is exposed to sufficient microwave or infrared energy to expand at least a majority of the expandable microspheres. The resulting product is a paper liner that has an adhesive that has expanded microspheres in it. The adhesive composition can then be exposed to sufficient thermal and / or radiation energy to fully cure the adhesive composition.

If desired, after application of the adhesive composition to the first side of the paper liner, a second paper liner having a first side and a second side can be provided and the first side of the second paper liner is applied to the surface. of the applied adhesive composition, forming an interleaving pattern. Therefore, the expansion of the microspheres and the curing of the adhesive can be carried out as explained above.

The present invention may be better understood through discussion of the following examples, which are not limited and are intended for invention only.

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MEXICAN INSTITUTE OF INDUSTRIAL PROPERTY

<img file="MX350366B_D0017.tif" />

help explain the

EXAMPLES

Example 1 - Formation of an adhesive with improved insulating properties

The adhesive composition having the following composition was prepared:

<td>Component</td><td>% in weigh</td>

<td>Water (1)</td><td> 17.20</td>

<td>Crosslinking agent^{1 2 3}</td><td> 0.14</td>

<td>Cooked starch</td><td> 1.09</td>

<td>Alkaline agent</td><td> 0.97</td>

<td>Water (2)</td><td> 9.73</td>

<td>Water (3)</td><td> 24.16</td>

<td>Moisturizer</td><td> 10.63</td>

<td>Unmodified starch</td><td> 34.78</td>

<td>Conservative⁴</td><td> 0.10</td>

<td>Expandable microspheres⁵</td><td> 1.20</td>

¹sodium tetraborate ²sodium hydroxide, 50% FCC, Rayon ³glycerol, glycerin, USP 99.7% ⁴Proxel GXL; 1,2-benzoisothiazolin-3-one⁵Expancel® microspheres

The water (1) was mixed with the crosslinking agent, and cooked starch was added. The mixture was heated in a 60 ° C (140 ° F) bath. The alkaline agent was added to the mixture, and mixed for two minutes to form a gel. The mixture was then removed from the bath, and

MEXICAN INSTITUTE ül

DE LA FROPIEUAO fKi

INDUSTRIAL add water (2). The mixture was mixed at high speed for 5-10 minutes. During this mixing process, a separate mixture of water (3), humectant and unmodified starch were mixed until it became uniform. The two mixtures were combined and mixed until uniform. Preservatives were then added to the resulting mixture and mixed for 10 minutes. The expanded microspheres were then added and the mixture was mixed for 10 minutes.

Example 2 - Formation of an adhesive with improved insulating properties

An adhesive composition was prepared having the following composition:

<td>Component</td><td>Weight (pounds)</td>

<td>Water (1)</td><td> 710</td>

<td>Starch with high concentration of amylose</td><td> 150</td>

<td>Caustic soda beads</td><td> 15</td>

<td>Primary Crosslinking Agents^{1 2}</td><td> 5.5</td>

<td>Water (2)</td><td> 1378</td>

<td>Secondary Crosslinking Agent A¹</td><td> 4</td>

<td>Unmodified Starch</td><td> 750</td>

<td>Secondary Crosslinking Agent B¹</td><td> 4</td>

<td>, , 2 Moisturizers</td><td> 15</td>

<td>Expandable microspheres</td><td> 36</td>

¹sodium tetraborate ²glycerin or urea

Water (1) is introduced into a first mixer and heated to 43.33 ° C (110 ° F). This heated water is

IMPÍOS adds high amylose starch, caustic soda beads and primary crosslinking agent. In a second mixer, water (2) is introduced and heated to 36.66 ° C (98 ° F). The secondary crosslinking agent A, the unmodified starch, the secondary crosslinking agent B, and the humectants are added and mixed. The two mixers combine and mix. The expandable microspheres are added to the resulting mixture.

Example 3 - Comparison of various adhesives

Four adhesive compositions (Cl, C2, C3, and I) were prepared, which are as follows: Composition Cl included an unmodified corn starch based on the adhesive composition (Stein-Hall adhesive) without expandable microspheres; Composition C2 includes an unmodified cornstarch based on the adhesive composition (SteinHall adhesive) with Dualite 130W microspheres; Composition C3 includes a starch-based adhesive composition made from a mixture of unmodified cornstarch and high-amylose cornstarch; and Composition I includes a starch based adhesive composition made from a blend of unmodified cornstarch and high amylose cornstarch with Dualite 130W microspheres. Adhesives were used in the formation of corrugated rollers that have different combinations of

<img file="MX350366B_D0018.tif" />

role from # 18 to # 23, and # 33 for

IMPI @

INSTITUTO MEXICANO DE LA PROPIEDAD INOUSTRíaL ___ the lining and for the middle part, and were they evaluated after drying? The resTiTEacioé are summarized below.

<td>Test</td><td>IMLorádari (fpm)</td><td>fWiiTinarri An de Papel by Ebczo-Paxta tfedia</td><td>Adhesive</td><td>Carplenento (Ib / dry nef)</td><td>SEC thickness (inch)</td><td>Peel strength (g / inch)</td><td>Observations</td>

<td> 1</td><td> 338</td><td> #18-#18</td><td>Cl *</td><td> 2.2</td><td> 0.055</td><td> 141</td><td>control, standard run</td>

<td> 2</td><td> 62</td><td> #18-#18</td><td>C2-A **</td><td> 4.1</td><td> 0.060</td><td> 22</td><td>no print lines on the back</td>

<td> 3</td><td> 295</td><td> #18-#18</td><td>C2B ***</td><td> 5.3</td><td> 0.057</td><td> 120</td><td>print lines on the back</td>

<td> 4</td><td> 360</td><td> #33-#33</td><td>C3-A</td><td> 0.81</td><td> 0.062</td><td>FT</td><td></td>

<td> 5</td><td> 360</td><td> #18-#18</td><td>C3-B</td><td> 0.82</td><td> 0.054</td><td>FT</td><td>warping of (CD) edge cross direction</td>

<td> 6</td><td> 344</td><td> #23-#18</td><td>C3-C</td><td> 1.35</td><td> 0.053</td><td>FT</td><td></td>

<td> 7</td><td> 344</td><td> #23-#18</td><td> 11</td><td> 4.78</td><td> 0.053</td><td>FT</td><td>some expansion</td>

<td> 8</td><td> 321</td><td> #23-#18</td><td> 12</td><td> 3.83</td><td> 0.055</td><td>FT</td><td>visible fillet</td>

<td> 9</td><td> 331</td><td> #23-#18</td><td> 13</td><td> 4.16</td><td> 0.058</td><td>FT</td><td>visible fillet</td>

<td> 10</td><td> 321</td><td> #23-#18</td><td> 14</td><td> 4.27</td><td> 0.057</td><td>FT</td><td>visible expansion</td>

<td> 11</td><td> 311</td><td> #18-#23</td><td> 15</td><td> 5.92</td><td> 0.056</td><td>FT</td><td>visible fillet</td>

<td> 12</td><td> 300</td><td> #18-#18</td><td> 16</td><td> 4.92</td><td> 0.055</td><td>FT</td><td>works great on splicing, flat sheets</td>

* Cross section of the paper seen in Figure 2 ** Cross section of the paper seen in Figure 3 *** Cross section of the paper seen in Figure 4

Complete tear (FT) indicates that the adhesive peel strength had sufficient strength and as such, the peel strength could not be measured. Observing the data generated, various observations were made. First, the inventive adhesive composition was found to have better peel strength than the control adhesive and the microsphere control adhesive. Furthermore, each of the tests using Composition I (inventive) was found to have a visible fillet and / or visible expansion, and thus can

IMPI

INSTITUTO MEXICANO jJ J-Λ

OF THE PROPERTY, it is concluded that the inventive composition forms supports (supports) that without microspheres. How can 'r / bstín. varse- * e »n — i · ® · composition C3, for example, the use of a composition using a high amylose adhesive without microspheres can lead to undesirable edge cross direction warping, especially for light weight paper . Additionally, it was found that the inventive adhesive composition can be useful in thinner midliner without any warping, and a high rate of corrugation can be used. Due to the expansion of the microspheres between the midline and the liner and also in the fillet supports, the heat resistance of the article can be increased due to the rigidity and strength of the article, which maintains the midline-liner configuration.

As can be seen, Composition I was very successful when used on each grade of paper, and particularly successful when used on the lowest grade of paper liner and middle part (Test 12). This test was found to work very well in splicing, and gives flat sheets.