阅读说明：本技术 用于施胶压制应用的制剂 (Formulations for size press applications ) 是由 D·J·卡斯特罗 V·F-P·马恩 S·R·马鲁 G·朴 于 2020-03-31 设计创作，主要内容包括：本文公开了纸处理组合物和使用所述纸处理组合物的方法。本公开的纸处理组合物可以包括强度剂和表面活性剂或施胶剂和表面活性剂。所述组合物和方法能够用于改进施胶和纸强度,尤其是例如在喷涂施胶压制应用中。(Disclosed herein are paper treatment compositions and methods of using the same. The paper treatment compositions of the present disclosure may include a strength agent and a surfactant or a sizing agent and a surfactant. The compositions and methods can be used to improve sizing and paper strength, particularly in spray size press applications, for example.)

1. A method of treating paper comprising:

applying a composition to a paper press roll to form a coated paper press roll, the composition comprising a strength agent, a sizing agent, and a surfactant; and

contacting paper with the coated paper press roll to form treated paper,

wherein the treated paper has a kobu value equal to or less than the kobu value of paper treated with the strength agent and the sizing agent but not with the surfactant.

2. The method of claim 1, wherein the composition is sprayed onto the paper press roll.

3. The method of any one of claims 1-2, wherein the surfactant comprises formula I:

wherein

n is an integer of 0 to 100;

m is an integer of 0 to 100;

x is an integer of 1 to 3;

y is an integer of 0 to 5; and is

R₁Is hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

4. The method of any one of claims 1-2, wherein the surfactant is selected from the group consisting of polyether polysiloxanes, alkoxylated ethylene diamines, and any combination thereof.

5. The method of any one of claims 1-4, wherein the surfactant is

6. The method of any of claims 1-5 wherein the treated paper has a cobble value that is at least about 10% less than the cobble value of paper treated with the strength agent and the sizing agent but not with the surfactant.

7. A method of treating paper comprising:

applying a composition to a paper press roll to form a coated paper press roll, the composition comprising a strength agent and a surfactant; and

contacting paper with the coated paper press roll to form treated paper,

wherein the tensile strength value of the treated paper is greater than the tensile strength value of paper treated with the strength agent but not with the surfactant.

8. A paper coating composition comprising:

a strength agent; and

a surfactant, a water-soluble surfactant and a water-soluble surfactant,

wherein the surface tension of the composition is at least about 5% less than a composition including the strength agent but not including the surfactant.

9. The composition of claim 8, wherein the surfactant is non-ionic.

10. The composition of any one of claims 8-9, wherein the surfactant is selected from the group consisting of polyether polysiloxanes, alkoxylated ethylene diamines, and any combination thereof.

11. The composition of any one of claims 8-10, wherein the surfactant comprises formula I:

wherein

n is an integer of 0 to 100;

m is an integer of 0 to 100;

x is an integer of 1 to 3;

y is an integer of 0 to 5; and is

R₁Is hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

12. The composition of any one of claims 8-11, wherein the surfactant comprises formula II:

wherein

n is an integer of 0 to 100; and is

R₁Is hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

13. The composition of any one of claims 8-12, wherein the surfactant comprises formula III:

14. the composition of any one of claims 8-10, wherein the surfactant is an ethylenediaminetetra (ethoxylate-block-propoxylate) tetraol.

15. The composition of claim 10, wherein the alkoxylated ethylenediamine has a molecular weight of about 3000Da to about 5000 Da.

16. The composition of any one of claims 8-15, wherein the strength agent is selected from the group consisting of anionic starch, nonionic starch, amphoteric starch, and any combination thereof.

17. The composition of any one of claims 8-16, further comprising a colorant.

18. The composition of any one of claims 8-17, comprising from about 2% to about 10% by weight of the strength agent and from about 0.005% to about 0.5% by weight of the surfactant.

19. A paper coating composition comprising:

a sizing agent; and

a surfactant, a water-soluble surfactant and a water-soluble surfactant,

wherein the contact angle of the composition on the surface of the size press roll is at least about 15% less than a composition including the sizing agent but not including the surfactant, or

The composition has a surface tension that is at least about 5% less than a composition that includes the sizing agent but does not include the surfactant.

20. A paper press roll comprising the composition of any one of claims 8-19.

21. Use of a composition according to claim 19 for sizing paper.

22. A method of treating paper comprising:

applying the composition of any one of claims 8-19 onto a paper press roll to form a coated paper press roll; and

contacting paper with the coated paper press roll.

23. A paper coating composition comprising:

a strength agent;

a sizing agent; and

a surfactant, a water-soluble surfactant and a water-soluble surfactant,

wherein the surface tension of the composition is at least about 5% less than a composition comprising the strength agent and the sizing agent, but not the surfactant.

1. Field of the invention

The present disclosure generally relates to formulations for treating substrates. More particularly, the present disclosure relates to size-press formulations and methods of treating paper using the size-press formulations.

2. Background of the invention

The spray size press attempts to minimize the wear traditionally associated with metered size presses by bypassing the "metering" of the film on the nip rolls. Alternatively, a spray size press requires the formulation to be sprayed onto the applicator roll in a very short time before it is pressed against the paper.

In the paper industry, "sizing" is the treatment of paper to make it resistant to penetration by liquids (especially water) or steam. The sizing agent can be applied to the surface internally through the wet end or as part of the size press formulation.

In general, the strength of paper products is a property having three categories called dry strength, wet strength or rewet strength, and wet web strength. Dry strength is the strength exhibited by a sheet of dry paper, typically adjusted at constant humidity and room temperature prior to testing. Wet strength or rewet strength is the strength exhibited by a paper sheet that has been completely dried and then rewetted with water prior to testing. Wet web strength is the strength of the cellulose fiber mat before drying into a paper product. Strength agents are compositions of matter that are effective in enhancing one or more of these strength properties.

Formulations having desirable properties for use in size press applications are needed. For example, agents that improve the sizing and/or strength properties of the treated paper.

Disclosure of Invention

A method of treating paper is provided. The method may include: applying a composition to a paper press roll to form a coated paper press roll, the composition comprising a strength agent, a sizing agent, and a surfactant; and contacting the paper with the coated paper press roll to form treated paper. The treated paper may have a cobble value equal to or less than the cobble value of paper treated with the strength agent and the sizing agent but not with the surfactant.

In some aspects, the composition can be sprayed onto the paper press roll.

In some aspects, the surfactant comprises formula I:

wherein n can be an integer of 0 to 100; m may be an integer of 0 to 100; x can be an integer of 1 to 3; y may be an integer of 0 to 5; and R is₁Can be hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

In some aspects, the surfactant may be selected from the group consisting of polyether polysiloxanes, alkoxylated ethylene diamines, and any combination thereof.

In some aspects, the surfactant can be

In some aspects, the treated paper may have a cobble value that is at least about 10% less than the cobble value of paper treated with the strength agent and the sizing agent but not with the surfactant.

A method of treating paper is also provided. The method may include: applying a composition to a paper press roll to form a coated paper press roll, the composition comprising a strength agent and a surfactant; and contacting the paper with the coated paper press roll to form treated paper. The treated paper may have a tensile strength value greater than the tensile strength value of paper treated with the strength agent but not with the surfactant.

A paper coating composition is provided. The composition may include a strength agent; and a surfactant. The surface tension of the composition may be at least about 5% less than a composition including the strength agent but not including the surfactant.

In some aspects, the surfactant can be nonionic.

In some aspects, the surfactant comprises formula II:

wherein n can be an integer of 0 to 100; and R is₁Is hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

In some aspects, the surfactant comprises formula III:

in some aspects, the surfactant may be an ethylene diamine tetra (ethoxylate-block-propoxylate) tetraol.

In some aspects, the alkoxylated ethylene diamine may have a molecular weight of about 3000Da to about 5000 Da.

In some aspects, the strength agent may be selected from the group consisting of anionic starch, nonionic starch, amphoteric starch, and any combination thereof.

In some aspects, the composition may include a colorant.

In some aspects, the composition can include from about 2% to about 10% by weight of the strength agent and from about 0.005% to about 0.5% by weight of the surfactant.

A paper coating composition is provided. The composition may include a sizing agent; and a surfactant. The contact angle of the composition on the surface of the size press roll may be at least about 15% less than the composition including the sizing agent but not including the surfactant, or the surface tension of the composition may be at least about 5% less than the composition including the sizing agent but not including the surfactant.

A paper press roll is provided comprising any of the compositions described herein.

There is provided the use of any of the compositions described herein for sizing paper.

A method of treating paper is also provided. The method may include: applying any of the compositions described herein onto a paper press roll to form a coated paper press roll; and contacting the paper with the coated paper press roll.

A paper coating composition is provided that may include a strength agent; a sizing agent; and a surfactant. The surface tension of the composition may be at least about 5% less than a composition including the strength agent and the sizing agent, but excluding the surfactant.

The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the application. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure. Those skilled in the art will also realize that such equivalent embodiments do not depart from the spirit and scope of the present disclosure as set forth in the appended claims.

Detailed Description

Various embodiments of the present disclosure are described below. The relationship and function of the various elements of the embodiments may be better understood by reference to the following detailed description. However, the embodiments are not limited to those explicitly described below.

A paper coating composition is provided. The composition may include a strength agent and a surfactant. In some aspects, the composition may optionally include a sizing agent, colorant, or other component.

In some aspects, the paper coating composition may consist of a strength agent, a surfactant, and water. The composition may exclude sizing agents, colorants, or other components. In some aspects, the paper coating composition may consist essentially of a strength agent, a surfactant, and water, thereby excluding any additional components that may affect the basic and novel properties of the composition. For example, a basic and novel property of the compositions disclosed herein is the reduction in surface tension when a surfactant is present, as compared to compositions without a surfactant.

In some aspects, a paper coating composition is provided that may include a sizing agent and a surfactant. In some aspects, the composition may optionally include a strength agent, colorant, or other component.

In some aspects, the paper coating composition may consist of a sizing agent, a surfactant, and water. The composition may exclude strength agents, colorants, or other components. In some aspects, the paper coating composition may consist essentially of a sizing agent, a surfactant, and water, thereby excluding any additional components that may affect the basic and novel properties of the composition.

A paper coating composition is provided that may include a strength agent, a sizing agent, and a surfactant. In some aspects, the composition may optionally include a colorant or other component.

In some aspects, the amount of surfactant on the paper is less than about 0.03 wt%.

In some aspects, the paper coating composition may consist of a strength agent, a sizing agent, a surfactant, and water. The composition may exclude colorants or other components. In some aspects, the paper coating composition may consist essentially of a strength agent, a sizing agent, a surfactant, and water, thereby excluding any additional components that may affect the basic and novel properties of the composition.

A paper coating composition is provided that may include a strength agent, a sizing agent, a colorant, and a surfactant. In some aspects, the composition may optionally include other components.

In some aspects, the paper coating composition may be comprised of a strength agent, a sizing agent, a colorant, a surfactant, and water. The composition may exclude other components. In some aspects, the paper coating composition may consist essentially of a strength agent, a sizing agent, a surfactant, a colorant, and water, thereby excluding any additional components that may affect the basic and novel properties of the composition.

In some aspects, the compositions disclosed herein can be aqueous solutions. In some aspects, the composition may or may not be an emulsion or dispersion.

In some aspects, the compositions disclosed herein can be sprayable. The sprayable composition is advantageously used in a spray size press, wherein the formulation is sprayed onto the applicator roll in a very short time before the applicator roll is pressed against the paper.

The pH of the paper coating composition is not particularly limited to any particular pH or pH range. In some aspects, the pH of the composition may be from about 3 to about 8.

The surface tension of the composition may be at least about 5% less than a composition including the strength agent but not including the surfactant. In some aspects, the surface tension of the composition may be at least about 5% less than a composition including the sizing agent but not including the surfactant. In some aspects, the surface tension of the composition may be at least about 5% less than a composition including the strength agent and the sizing agent, but not including the surfactant.

In some aspects, the surface tension of the composition may be from about 5% to about 90% less than a composition having the same components except for the surfactant. In some aspects, the surface tension of the composition may be from about 5% to about 90%, from about 10% to 90%, from about 20% to 90%, from about 10% to about 80%, from about 10% to about 70%, or from about 20% to about 70% less than that of a composition having the same components except for the surfactant. In some aspects, the surface tension of the composition may be reduced by about 10%, about 20%, about 30%, about 40%, about 50%, about 60%, or about 70% when a surfactant is added to the composition.

Surface tension may be determined using techniques known in the art. For example, surface tension can be determined using the Wilhelmy plate technique and can be reported in millinewtons per meter (mN/m).

Another property used to determine the effect of a surfactant on a composition may be contact angle. The contact angle of a droplet on a surface is defined as the angle formed by two lines: the tangent to the solid surface and the liquid droplet, which intersects the point where the liquid, solid and air interfaces meet. The smaller the contact angle, the higher the affinity and wettability of the droplet to the surface. The contact angle of the composition on the surface of the roller may be at least about 15% less than a composition without the surfactant. In some aspects, the contact angle of the composition on the surface of the roller may be from about 15% to about 60%, from about 20% to about 60%, or from about 20% to about 50% less than a composition without the surfactant. The contact angle may be measured using methods known to those of ordinary skill in the art, such as, for example, image analysis techniques.

The compositions disclosed herein may include a surfactant. As used herein, "surfactant" includes anionic, nonionic, cationic, amphoteric and zwitterionic surfactants.

In some aspects, the surfactant can be nonionic.

In some aspects, the surfactant can be a polyether polysiloxane. For example, the polyether polysiloxane may have the chemical structure of formula I.

Wherein n can be an integer of 0 to 100; m may be an integer of 0 to 100; x can be an integer of 1 to 3; y may be an integer of 0 to 5; and R is₁Can be hydrogen, halogen, C_1-10Alkyl, phenyl or cycloalkyl.

In some aspects, n can be an integer from 1 to 50, 1 to 20, or 1 to 10; m can be an integer of 0-50, 0-20 or 0-10; x may be 1; y may be 0; and R is₁Can be hydrogen, halogen or C_1-10An alkyl group.

In some aspects, n can be 1 to 50, 1 to 20, or 1 to 10. In some aspects, n may be 1. In some aspects, m may be 0 to 50, 0 to 20, or 0 to 10. In some aspects, m may be 0.

In some aspects, x may be 1 and y may be 0.

In some aspects, R₁Can be hydrogen, halogen or C_1-10An alkyl group. In some aspects, R₁May be a methyl group.

As used herein, the term "alkyl" refers to a straight or branched chain hydrocarbon group preferably having 1 to 10 carbon atoms (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms). Alkyl groups include, but are not limited to, methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, isobutyl, t-butyl, sec-butyl), pentyl (e.g., n-pentyl, isopentyl, t-pentyl, neopentyl, sec-pentyl, 3-pentyl), hexyl, heptyl, octyl, nonyl, and decyl. An alkenyl group may be unsubstituted or substituted with one or more suitable substituents.

The term "cycloalkyl" as used herein refers to a mono-, bi-, or tricyclic carbocyclic group (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclopentenyl, cyclohexenyl, bicyclo [2.2.1] heptyl, bicyclo [3.2.l ] octyl, and bicyclo [5.2.0] nonyl, and the like); optionally containing 1 or 2 double bonds. Cycloalkyl groups may be unsubstituted or substituted with one or more suitable substituents.

In some aspects, the surfactant comprises formula II:

in some aspects, the surfactant comprises formula III:

in some aspects, the surfactant may be an alkoxylated ethylenediamine, such as, for example, ethylenediamine tetra (ethoxylate-block-propoxylate) tetraol.

In some aspects, the alkoxylated ethylene diamine may have a molecular weight of about 3000Da to about 5000 Da.

The compositions disclosed herein may include from about 0.005% to about 0.5% by weight of a surfactant. In some aspects, the composition can include from about 0.0001% to about 1% by weight of a surfactant. In some aspects, the composition may include about 0.01 wt%, about 0.02 wt%, about 0.03 wt%, or about 0.1 wt% surfactant.

Suitable strength agents may include, but are not limited to, natural polymers such as starch, carboxymethylcellulose (CMC), xanthan gum, and guar gum. Suitable strength agents may include, but are not limited to, synthetic polymers such as polyacrylamides (cationic, anionic, and amphoteric), Glyoxalated Polyacrylamides (GPAM), polyamidoamine epihalohydrin-based polymers, and polyvinylamines.

In some aspects, the starch may be, for example, anionic, cationic, nonionic or amphoteric starch, particularly anionic, nonionic or amphoteric starch, from a variety of plants, including corn, potato, wheat, tapioca or sorghum, optionally modified by enzymatic, high temperature or chemical/thermal conversion techniques, such as oxidized starch, ethylated starch or pearl starch. In some aspects, the starch may include: native starch, modified starch, amylase, amylopectin, styrene starch, butadiene starch, starches containing various amounts of amylase and amylopectin such as 25% amylase and 75% amylopectin (corn starch) and 20% amylase and 80% amylopectin (potato starch); enzyme-treating starch; hydrolyzing starch; heating starch, also known in the art as "paste starch"; cationic starches, such as those resulting from the reaction of starch with tertiary amines to form quaternary ammonium salts; a non-ionic starch; an anionic starch; amphoteric starch (containing cationic and anionic functional groups); cellulose and cellulose-derived compounds; and any combination thereof and/or combinations thereof which explicitly exclude one or more of these.

In some aspects, the composition may have from about 1% to about 20%, from about 1% to about 15%, from about 1% to about 10%, or from about 1% to about 5% by weight of the strength agent. In some aspects, the composition may have about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, or about 10 wt% strength agent. In some aspects, the composition may have from about 1% to about 20%, from about 1% to about 15%, from about 1% to about 10%, or from about 1% to about 5% by weight of the nonionic starch.

Suitable sizing agents include, but are not limited to, rosin sizing agents and water-insoluble hydrophobic cellulose sizing agents, such as alkyl ketene dimers ("AKD"), Alkenyl Succinic Anhydride (ASA), Styrene Acrylic Acid (SAA) emulsions, Styrene Acrylate Emulsions (SAE), Styrene Maleic Anhydride (SMA) emulsions, Ethylene Acrylic Acid (EAA), polyurethanes, and mixtures thereof. For example, the sizing agent may be Perglutin 400.

Suitable colorants can include, but are not limited to, organic compounds having a conjugated double bond system; an azo compound; a metal azo compound; anthraquinones; triaryl compounds such as triarylmethane; quinolines and related compounds; acid dyes (anionic organic dyes containing sulfonate groups, used with organic compounds such as alum); basic dyes (cationic organic dyes containing amine functionality); and direct dyes (acid dyes with high molecular weight and a direct affinity for cellulose); and combinations of the above-listed suitable dye compounds.

In some aspects, the colorant may be Cartasol Brown.

The presently disclosed compositions may include various components. Further, the formulation may be water-based, hydrocarbon-based, organic solvent-based, emulsion-based (water-in-oil, oil-in-water), and the like.

Other components may include, but are not limited to, optical brighteners, biocides, retention aids, defoamers, pH control agents, pitch control agents, and drainage aids.

For example, the component may be a polyaluminum chloride (PAC) compound. Any PAC may be used in accordance with the present disclosure. In some aspects, the PAC is selected from the group consisting of phosphated polyaluminum chloride, sulfated polyaluminum chloride, polyaluminum silicoaluminum sulfate chloride, and any combination thereof. In some aspects, the PAC is phosphated polyaluminum chloride.

In other aspects, any of the compositions disclosed herein can be disposed on a surface of a paper press roll. In some aspects, the paper press roll may be a size press roll. The composition may be disposed on at least a portion of the surface of the roll. In some aspects, the composition may be sprayed over the entire surface of the size press roll. In some aspects, the composition may be sprayed over at least a portion of the surface of the size press roll.

A method of treating paper is provided. The method may include: applying any of the compositions described herein to a paper press roll to form a coated paper press roll; and contacting the paper with the coated paper press roll.

In some aspects, certain components of the composition may be applied separately to the paper press roll in separate compositions. For example, a composition comprising a strength agent and a surfactant may be sprayed onto the roller separately from a composition comprising a sizing agent and a surfactant.

When a surfactant is included in the paper coating composition, the properties of the treated paper may be enhanced. For example, surfactants may enhance the action of the strength agent in the composition. Without being bound by any particular theory, the surfactant allows the strength agent to penetrate the paper, thereby imparting improved bulk strength characteristics.

The treated paper may have a cobble value equal to or less than the cobble value of paper treated with the strength agent and sizing agent but not with the surfactant. In some aspects, the treated paper may have a cobble value equal to or less than the cobble value of paper treated with the strength agent and sizing agent but not with the surfactant.

In some aspects, the ratio of the cobble value of the treated paper to the cobble value of paper treated with the strength agent or size but not treated with the surfactant may be from about 5% to about 40%, from about 5% to about 30%, from about 10% to about 30%, or from about 10% to about 20%.

In some aspects, the treated paper may have improved bulk strength properties such as short Span Compression Test (SCT) strength, tensile strength, Concora flute edge crush (CFC) strength, ring crush strength, and burst strength compared to paper treated with strength agent but not with surfactant. Bulk strength may be measured by any technique known to those of ordinary skill in the art. For example, SCT can be measured as defined in TAPPI method T826 om-04; tensile strength can be measured as defined in TAPPI method T494 om-13; CFC can be measured as defined in TAPPI method T843 om-02; the ring crush strength can be measured as defined in TAPPI method T822 om-02; and the burst strength can be measured as defined in TAPPI method T403 om-02. In other aspects, the tensile strength value of the treated paper may be greater than the tensile strength value of paper treated with the strength agent but not with the surfactant.

In some aspects, the bulk strength property may be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the SCT intensity can be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the tensile strength may be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the CFC strength may be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the ring crush strength can be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the burst strength may be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%.

In some aspects, the two or more bulk strength properties may be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the burst strength and SCT can be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%. In some aspects, the CFC and SCT strengths can be increased by at least about 5%, at least about 10%, at least about 15%, or at least about 20%.

In some aspects, the composition can be sprayed onto the paper press roll.

The methods described in this disclosure can be practiced on conventional papermaking equipment. Although papermaking equipment varies in operation and mechanical design, the process of making paper on different equipment contains common stages. Papermaking typically includes a pulping stage, a bleaching stage, a stock stage, a wet end stage, and a dry end stage.

In the pulping stage, individual cellulose fibers are released from a source of cellulose by mechanical and/or chemical action. The pulp is suspended in water in the stock preparation stage. The wet-end stage of the papermaking process involves depositing a stock suspension or pulp slurry on a wire or felt of a paper machine to form a continuous fibrous web, drying the web and consolidating the web ("pressing") to form a sheet of paper. In the dry end stage of the papermaking process, the web is dried and may be subjected to additional processing, such as passing it through size press, calendering, spraying with surface modifying agents, printing, cutting, corrugating, and the like. In addition to using a size press and/or calender water box, the dried paper can also be treated by spraying using a spray boom.

As used herein, "dry end" means the portion of the papermaking process, including the press section and subsequent thereto, where the liquid medium, such as water, typically comprises less than 45% of the mass of the substrate, including, but not limited to, the size press portion of the papermaking process, where the additives added typically remain in a distinct coating outside the slurry.

The present disclosure contemplates the use of a paper coating composition in one or more stages of the papermaking process described above.

A typical paper machine includes components such as a dryer, a calendering system, and a surface sizing system. The surface sizing system may include a size press that applies sizing agents or other compounds, such as optical brighteners, to the surface of the paper. Generally, the size press applies various solutions or formulations to the surface of the paper. The paper may have been dried or partially dried prior to processing by the size press.

In some aspects, the paper coating composition may be applied to the paper substrate as a surface treatment. For example, if the substrate is paper, the composition may be applied to one or both sides of the paper.

In some aspects, the paper substrate on which the composition is applied is not creped paper.

Typically, the paper coating composition can be applied at or near the size press, but can undoubtedly be applied at other locations in the papermaking process. In most cases, the size press is located downstream of the first drying stage. The composition may be applied using a conventional size press, but may be applied using other components/techniques, such as spraying, doctor blades, or other conventionally used coating equipment.

It should be noted that applying the chemical at, near, or after the size press may be distinguished from applying the chemical at the wet end of the paper machine. One difference relates to the fact that the paper is dried or at least partially dried before it reaches the size press.

Examples

Measurements of surface tension (Wilhelmy plate technique) and viscosity (Brookfield with small sample adapter) were performed on the coating formulations at 60 ℃ in the laboratory work reported below. Contact angle (image analysis technique) measurements were performed with formulations approaching 60 ℃, but the substrate was not at this temperature. Next, the cobb sizing test was used to measure the sizing response for sheets coated with wire-wound rods using the draw down method.

Example 1:

the following table shows the effect of three different surfactants on the surface tension of an approximately 5 wt% anionic starch solution. The surfactants tested were labeled AK and represent the compounds a ═ Tegopren 5840, B ═ Silwet L-77, C ═ Plurafac RA 300, D ═ Dow Corning 502W, E ═ Pluronic 31R1, F ═ Tetronic 701, G ═ Tetronic 901, H ═ Airase 5600, I ═ Airase 5700, J ═ Dow Corning 57, and K ═ Dow Corning 501W. Surfactants A, B, D and K are considered to be super wetting agents. Surfactants E, F and G are defoamers. Surfactants H and I are silicone defoamers. Surfactant J is a silicone glycol copolymer and surfactant C is a low foaming wetting agent.

TABLE 1 surface tension of starch solution and surfactant ("ppm" for parts per million).

Example 2:

study 2 demonstrates the sensitivity of the surface tension of a starch solution to the presence of a surfactant in the absence or presence of a surface sizing agent and a dye.

TABLE 2 Effect of sizing agents and dyes on surface tension

Example 3

The effect of several surfactants on surface tension and sizing response is summarized in table 3 below. These studies emphasize that different surfactants affect the different magnitudes of solution surface tension and sizing response of the treated paper, with the surfactant concentration in the solution maintained constant at about 100 ppm.

Table 3. effect of surfactants on surface tension and sizing response (cobb). "lb/t" represents pounds of active per 2000 pounds of dry paper.

The results are summarized in Table 4 below, where the dosages of surfactants B and G are in the range of 0-300ppm and 0-200 ppm. In each case, a reduction of about 10mN/m in surface tension was observed when dosing 200 ppm.

TABLE 4 dosage curves for surfactants B and G.

Example 5:

in size press applications, solution viscosity is an important parameter: the high viscosity limits the transfer of the solution to the paper, negatively affecting the overall production rate. Table 5 below shows that the effect of up to 100pm of surfactant in the coating solution has a negligible effect on viscosity.

TABLE 5 Effect of surfactants on solution viscosity.

The following table summarizes the contact angle results for solutions containing up to 300ppm of surfactants B and G.

TABLE 6 influence of surfactant on the contact angle of the droplets with the roller surface.

All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While this invention may be embodied in many different forms, there are described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. In addition, unless expressly stated to the contrary, use of the term "a" or "an" is intended to include "at least one" or "one or more". For example, "surfactant" is intended to include "at least one surfactant" or "one or more surfactants".

Any ranges given in absolute terms or in approximate terms are intended to encompass both, and any definitions used herein are intended to be clear and not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein (including all fractional and whole values).

Furthermore, the invention encompasses any and all possible combinations of some or all of the various embodiments described herein. It should also be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.