Patent Application
20250027275
The present disclosure generally relates to methods of improving a papermaking process. More particularly, the disclosure provides compositions and methods for reducing dust in a papermaking process.
Tissuemaking involves the preparation of a paper product from an aqueous suspension of cellulosic fibers by forming a wet web of interwoven fibers and removal of water from the wet web by various dewatering methods, such as free drainage, vacuum, pressing, and evaporative drying, to form a sheet. The sheet is then transferred to a heated cylinder (e.g., Yankee dryer) to further reduce the moisture content by evaporative and convective (hot air impingement from hoods) drying. The sheet is then subjected to a creping process where it is scraped off the cylinder.
The creping process typically suffers from dusting issues, which occur during contact of the creping blade with the sheet. Loose dust particles are generated when mechanical force is applied to soften the sheet by weakening the bonding between fibers. Similar dusting issues can arise while converting the original roll of paper (e.g., cutting the original roll into the desired size).
Excessive dusting can pose problems during the manufacture of tissue products, and can result in runnability and quality issues on papermaking machines. Moreover, dust and lint accumulation can create a fire hazard. There is also the potential for workers to be exposed to paper dust. Regular exposure to high levels of dust can affect the respiratory system and cause illness.
A number of methods are used to reduce dusting. Air jets, as well as vacuum systems positioned near the papermaking process, have been used to remove dust released from the paper substrate, but these methods are generally energy inefficient and do not address dust generated by handling of the paper sheet/products.
The present disclosure provides methods and compositions for improving a papermaking process. A method may comprise adding an effective amount of a composition to a foraminous surface, wherein the composition comprises an oil, an emulsifying surfactant, and a formulation aid. The method may further comprise contacting the foraminous surface with a furnish comprising water and pulp, draining the water through the foraminous surface, forming a sheet comprising the pulp on the foraminous surface, and conveying the sheet through the remainder of the process/machine, such as conveying the sheet from the foraminous surface to a felt, a belt, a fabric, a dryer, etc.
In some embodiments, the method further comprises transferring the sheet to a dryer.
In some embodiments, the method further comprises adding the composition through a chemical shower.
In certain embodiments, the method further comprises adding the composition before the sheet is formed. In certain embodiments, the method further comprises adding the composition before the sheet is transferred to the felt, belt, fabric, etc.
In some embodiments, the method further comprises adding the composition in a forming zone of a papermaking machine.
In some embodiments, the method further comprises adding the composition to a side of the foraminous surface that contacts the sheet.
In certain embodiments, the method further comprises adding the composition when the sheet has a moisture content from about 80 wt. % to about 99.9 wt. %. In certain embodiments, the composition is added in the absence of a pulp furnish.
In some embodiments, the method further comprises transferring the dried sheet to a creping process and/or a converting process, and reducing dust generation during the creping process and/or the converting process.
In some embodiments, the oil is selected from the group consisting of a mineral oil, a non-silicon-based oil, a vegetable oil, biodiesel, a synthetic oil, and any combination thereof. In certain embodiments, the composition comprises from about 50 wt. % to about 95 wt. % of the oil.
In some embodiments, the emulsifying surfactant is a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant with a net negative charge, an amphoteric surfactant with a net positive charge, a polymeric surfactant, and any combination thereof. In some embodiments, the emulsifying surfactant is an ethoxylated alcohol. In certain embodiments, the ethoxylated alcohol comprises a C10-C16 ethoxylated alcohol. In some embodiments, the composition comprises from about 1 wt. % to about 25 wt. % of the emulsifying surfactant.
In some embodiments, the formulation aid is selected from the group consisting of a fatty acid, a fatty alcohol, a fatty ether, a fatty ester, a triglyceride, a lipophilic surfactant, and any combination thereof. In certain embodiments, the acid is tall oil fatty acid. In some embodiments, the composition comprises from about 1 wt. % to about 20 wt. % of the formulation aid.
In some embodiments, the effective amount is between about 1 and about 60 mg/m2.
In certain embodiments, the foraminous surface comprises a forming fabric.
In some embodiments, the method further comprises carrying out the draining step using gravity, centrifugal force, and/or a vacuum.
In some embodiments, the sheet comprises a natural fiber, a synthetic fiber, a chemical pulp, a mechanical pulp, a vegetable fiber, a recycled fiber, a filler, or any combination thereof.
In certain embodiments, the composition is not added after transferring the sheet to the felt, belt, fabric, etc.
In some embodiments, the composition is not added after the sheet comprises about 20% consistency.
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 that form the subject of the claims of this application.
A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:
Various embodiments are described below with reference to the drawings in which like elements generally are referred to by like numerals. The relationship and functioning of the various elements of the embodiments may better be understood by reference to the following detailed description. However, embodiments are not strictly limited to those illustrated in the drawings or described below.
Examples of methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in practice or testing of the present disclosure. All publications, patent applications, patents and other reference materials mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and not intended to be limiting.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control.
The term “pulp furnish” means a mixture comprising a liquid medium, such as water, within which solids, such as fibers (for example cellulose fibers) and optionally fillers, are dispersed or suspended such that between about >99% to about 45% by mass of the furnish is liquid medium. The portion of the papermaking process prior to the press section (or prior to the through air dryers if working on a TAD machine) where a liquid medium, such as water, comprises more than about 45% of the mass of the substrate is referred to as the “wet end.” When working with a TAD machine, through air dryers will dry the sheet from approximately 20% consistency to about 65-90% consistency prior to the Yankee dryer. The term “dry end” refers to that portion of the papermaking process including and subsequent to the press section (or through air dryers) where a liquid medium, such as water, typically comprises less than about 45% of the mass of the substrate. The compositions and methods disclosed herein can be incorporated into or carried out in the “wet end” and/or “dry end” of the papermaking process.
The pulp furnish, and thus a sheet formed from the furnish, may comprise, for example, a natural fiber, a synthetic fiber, a chemical pulp, a mechanical pulp, a vegetable fiber, a recycled fiber, a filler, or any combination thereof.
Certain aspects of the present disclosure relate to compositions that can be used to improve papermaking processes. For example, the compositions may be used to reduce dust in a papermaking process. The compositions include an oil, an emulsifying surfactant, and a formulation aid.
The oil is not particularly limited and may be selected from a variety of different oils. For example, the oil may be selected from the group consisting of a mineral oil, a non-silicon-based oil, a vegetable oil, biodiesel, a synthetic oil, and any combination thereof.
Illustrative, non-limiting examples of mineral oils include white mineral oil, gear oil, dryer oil, turbine oil, spindle oil, liquid paraffin, isoparaffin, naphthene, and the like.
Illustrative, non-limiting examples of vegetable oils include soybean oil, canola oil, sunflower oil, peanut oil, coconut oil, olive oil, palm oil, linseed oil, castor oil, tung oil, tall oil, rapeseed oil, corn oil, and the like.
Illustrative, non-limiting examples of synthetic oils include polyalphaolefin, synthetic ester oil, polyalkylene glycol, synthetic fatty acids, and the like.
The compositions disclosed herein may comprise varying amounts of the oil. For example, a composition may comprise from about 50 wt. % to about 95 wt. % of the oil. In some embodiments, a composition may comprise from about 55 wt. % to about 95 wt. %, about 60 wt. % to about 95 wt. %, about 65 wt. % to about 95 wt. %, about 70 wt. % to about 95 wt. %, about 75 wt. % to about 95 wt. %, about 80 wt. % to about 95 wt. %, about 85 wt. % to about 95 wt. %, about 80 wt. % to about 90 wt. %, or about 85 wt. % of the oil.
The emulsifying surfactant is not particularly limited and may be selected from, for example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant with a net negative charge, an amphoteric surfactant with a net positive charge, a zwitterionic surfactant, a polymeric surfactant, and any combination thereof.
Illustrative, non-limiting examples of surfactants include fatty acids, such as palmitic, stearic, linoleic, oleic and tall oil fatty acids; alkoxylated alcohols; alkoxylated fatty acids; alkoxylated alkylphenols; sulfates and sulfonates of oils and fatty acids; sodium petroleum sulfonates; sulfonates of naphthalene and alkyl naphthalenes; sucrose and glucose esters and derivatives thereof; fatty esters, ethoxylated fatty esters and glycerol esters; and any combination thereof.
In accordance with certain embodiments, the emulsifying surfactant is an ethoxylated alcohol. The ethoxylated alcohol may comprise, for example, a C10-C16 ethoxylated alcohol, such as a C12-C16 ethoxylated alcohol, a C14-C16 ethoxylated alcohol, a C10-C14 ethoxylated alcohol, a C10-C12 ethoxylated alcohol, a C10 ethoxylated alcohol, a C11 ethoxylated alcohol, a C12 ethoxylated alcohol, a C13 ethoxylated alcohol, a C14 ethoxylated alcohol, a C15 ethoxylated alcohol, or a C16 ethoxylated alcohol.
In some embodiments, the surfactant is selected from the group consisting of a fatty acid, an alkoxlyated alcohol, an alkoxylated fatty acid, a sucrose ester, a glucose ester, a polyethylene glycol, and any combination thereof.
In certain embodiments, the surfactant is selected from the group consisting of an ethoxylated alcohol, an ethoxylated fatty acid, and any combination thereof.
The amount of emulsifying surfactant in the composition may vary. For example, the composition may comprise from about 1 wt. % to about 25 wt. % of the emulsifying surfactant, such as from about 1 wt. % to about 20 wt. %, about 1 wt. % to about 15 wt. %, about 1 wt. % to about 10 wt. %, about 1 wt. % to about 5 wt. %, about 5 wt. % to about 25 wt. %, about 10 wt. % to about 25 wt. %, about 15 wt. % to about 25 wt. %, or about 20 wt. % to about 25 wt. % of the emulsifying surfactant.
The formulation aid of the composition promotes film forming of non-polar oil on the dryer cylinder and/or canvas (wire of fabric) surface. It may be selected from, for example, an acid, a fatty acid, a fatty alcohol, a fatty ether, a fatty ester, a triglyceride, a lipophilic surfactant, and any combination thereof. In certain embodiments, the acid is tall oil fatty acid.
The amount of formulation aid in the composition is variable. For example, the composition may comprise from about 1 wt. % to about 20 wt. % of the formulation aid, such as from about 1 wt. % to about 18 wt. %, about 1 wt. % to about 16 wt. %, about 1 wt. % to about 14 wt. %, about 1 wt. % to about 12 wt. %, about 1 wt. % to about 10 wt. %, about 1 wt. % to about 8 wt. %, about 1 wt. % to about 6 wt. %, about 1 wt. % to about 4 wt. %, about 4 wt. % to about 20 wt. %, about 6 wt. % to about 20 wt. %, about 8 wt. % to about 20 wt. %, about 10 wt. % to about 20 wt. %, about 12 wt. % to about 20 wt. %, about 14 wt. % to about 20 wt. %, about 16 wt. % to about 20 wt. %, or about 18 wt. % to about 20 wt. % of the formulation aid.
A composition disclosed herein may include an additional additive, such as a wet strength aid, a dry strength aid, a debonding agent, a softening agent, an adhesive, a sizing agent, a dye, an optical brightener, an absorbency aid, a flocculant, a coagulant, a microparticle, an odor control material, a deodorant, a pigment, a humectant, an emollient, a bactericide, a buffer, a wax, a zeolite, a lotion, a perfume, a superabsorbent, a fungicides, a moisturizer, and any combination thereof.
The compositions disclosed herein may comprise an additive used to improve the softness of the produced sheet. Illustrative, non-limiting examples include organic quaternary salts having fatty chains of about 12 to about 22 carbon atoms, such as dialkyl imidazolinium quaternary salts, dialkyl diamidoamine quaternary salts, monoalkyl trimethylammonium quaternary salts, dialkyl dimethylammonium quaternary salts, trialkyl monomethylammonium quaternary salts, ethoxylated quaternary salts, dialkyl and trialkyl ester quaternary salts, and the like. Additional suitable additives include polysiloxanes, quaternary silicones, organoreactive polysiloxanes, amino-functional polydimethylsiloxanes, and the like.
The amount of the optional additional additive may vary depending upon the particular circumstances. For example, the composition may comprise from about 0.1 wt. % to about 20 wt. % of the additional additive, such as from about 0.1 wt. % to about 18 wt. %, about 0.1 wt. % to about 16 wt. %, about 0.1 wt. % to about 14 wt. %, about 0.1 wt. % to about 12 wt. %, about 0.1 wt. % to about 10 wt. %, about 0.1 wt. % to about 8 wt. %, about 0.1 wt. % to about 6 wt. %, about 0.1 wt. % to about 4 wt. %, about 0.1 wt. % to about 2 wt. %, or about 0.1 wt. % to about 1 wt. % of the additional additive.
The paper manufacturing process can be organized into different general sections. For example, with respect to
The sheet travels from the forming fabric to the felt, which is located in the press section. The press section removes much of the remaining water via a system of nips formed by rolls pressing against each other aided by press felts that support the sheet and absorb the pressed water. The felts run through the nips of the press rolls and continue around a felt run, normally consisting of several felt rolls. During the dwell time in the nip, the moisture from the sheet is transferred to the press felt. The sheet (about 20% consistency at this point) is then transferred from the felt to the dryer section, where the pressed layer moves through one or more heated rollers (e.g., a Yankee dryer).
As the sheet travels around the Yankee dryer, the consistency increases, as shown in
When the dried sheet is transferred to a creping process and/or a converting process, an unexpectedly significant reduction in dust generation during the creping process and/or the converting process is achieved due to the presently disclosed technology. For example, a web/sheet that has been produced on a foraminous surface that has been treated with a composition disclosed herein produces less dust at the creping blade as compared to a sheet that was produced using a foraminous surface that was not treated with a composition of the present disclosure.
It should be noted that the compositions and methods disclosed herein can be used with a conventional papermaking machine but they can be used with other machines as well, such as a through-air drying (TAD) machine.
In some embodiments, the composition is added before the sheet is formed. In certain embodiments, the composition is added before the sheet is transferred to the felt. In some embodiments, the composition is not added after transferring the sheet to the felt. If the methods disclosed herein are carried out on a TAD machine, the compositions may be added, for example, to a fabric, such as the inner or outer forming wires.
When using a TAD machine, the wet sheet is dried by means of through-air dryers, whereby hot air is passed through the sheet. This process preserves the bulk of the sheet and provides improved softness. The wet sheet is carried to the through-air dryer by means of a fabric (referred to as a TAD fabric). The TAD fabric has a 3-dimensional character and serves to mold or pattern the wet sheet so that when dry, this pattern remains in the sheet. In order for effective patterning of the sheet to occur, the wet sheet must be pulled into the fabric by a vacuum molding box. However, after the sheet is dry, it must be transferred from the TAD fabric for additional processing.
In a creped TAD process, the sheet is transferred to a Yankee dryer and creped prior to final winding on the reel. In an un-creped TAD process, the sheet is separated from the fabric and sent directly to the reel. In both processes, the sheet that has been intimately molded into the 3-dimensional TAD fabric must be separated from the TAD fabric without damaging the sheet.
The compositions disclosed herein may be applied to the foraminous surface, felt, fabric, wire, etc., by various means known in the art. For example, the composition may be applied using a chemical shower/spray boom. The shower may be located at any of the application points discussed above in connection with
When a chemical shower is used, a spray nozzle or multiple spray nozzles may be used to spray the composition onto the foraminous surface. In some embodiments, the composition may be applied to the side of the foraminous that contacts the sheet. In some embodiments, the composition is only applied to the side of the foraminous surface that contacts the sheet. In other embodiments, the composition may be applied to either or both sides of the foraminous surface. The composition may be applied continuously or intermittently.
The effective amount of the composition to be added to the foraminous surface may differ depending upon the specific situation. For example, the effective amount may range from about 1 mg/m2 to about 60 mg/m2, about 1 mg/m2 to about 50 mg/m2, about 1 mg/m2 to about 40 mg/m2, about 1 mg/m2 to about 30 mg/m2, about 1 mg/m2 to about 20 mg/m2, about 1 mg/m2 to about 10 mg/m2, about 3 mg/m2 to about 10 mg/m2, about 3 mg/m2 to about 20 mg/m2, about 3 mg/m2 to about 30 mg/m2, about 3 mg/m2 to about 40 mg/m2, about 3 mg/m2 to about 50 mg/m2, about 3 mg/m2 to about 60 mg/m2, about 5 mg/m2 to about 60 mg/m2, about 10 mg/m2 to about 60 mg/m2, about 20 mg/m2 to about 60 mg/m2, or about 30 mg/m2 to about 60 mg/m2.
In accordance with the present disclosure, moisture content/sheet consistency may be used to determine when the composition is added to the foraminous surface. For example, the composition may be added when the sheet has a moisture content from about 80 wt. % to about 99.9 wt. %, such as from about 85 wt. % to about 99.9 wt. %, about 90 wt. % to about 99.9 wt. %, about 95 wt. % to about 99.9 wt. %, about 80 wt. % to about 99 wt. %, about 80 wt. % to about 95 wt. %, or about 80 wt. % to about 90 wt. %. In some embodiments, the composition is not added once the moisture content drops below about 85 wt. %, about 80 wt. %, or about 75 wt. %.
The composition of the present disclosure may be added, for example, when a sheet has a consistency of about 0.1% to about 20%. For example, the composition may be added when the sheet has a consistency of about 0.1% to about 20%, about 1% to about 20%, about 5% to about 20%, about 10% to about 20%, about 15% to about 20%, about 0.1% to about 15%, about 0.1% to about 10%, or about 0.1% to about 5%. In some embodiments, the composition is not added after the sheet comprises about 15%, about 20%, or about 25% consistency.
The foregoing may be better understood by reference to the following examples, which are intended for illustrative purposes and are not intended to limit the scope of the disclosure or its application in any way.
A composition of the present disclosure was added to a forming fabric of a conventional tissuemaking machine. The composition was added via a single coverage chemical shower in an amount ranging between about 3 and about 30 mg/m2. The composition was applied to a side of the fabric that contacts the sheet before the transfer of the sheet to the felt. The composition was a mineral oil-based product that included an emulsifying surfactant and a formulation aid. A significant reduction in dust generation was observed at the creping blade and during the converting process as compared to a sheet produced without treatment of the forming fabric with a composition of the present disclosure.
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” is intended to include “at least one” or “one or more.” For example, “a surfactant” is intended to include “at least one surfactant” or “one or more surfactants.”
Any ranges given either in absolute terms or in approximate terms are intended to encompass both, and any definitions used herein are intended to be clarifying 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 (including all fractional and whole values) subsumed therein.
Any composition disclosed herein may comprise, consist of, or consist essentially of any element, component and/or ingredient disclosed herein or any combination of two or more of the elements, components or ingredients disclosed herein.
Any method disclosed herein may comprise, consist of, or consist essentially of any method step disclosed herein or any combination of two or more of the method steps disclosed herein.
The transitional phrase “comprising,” which is synonymous with “including,” “containing,” or “characterized by,” is inclusive or open-ended and does not exclude additional, un-recited elements, components, ingredients and/or method steps.
The transitional phrase “consisting of” excludes any element, component, ingredient, and/or method step not specified in the claim.
The transitional phrase “consisting essentially of” limits the scope of a claim to the specified elements, components, ingredients and/or steps, as well as those that do not materially affect the basic and novel characteristic(s) of the claimed invention.
As used herein, the term “about” refers to the cited value being within the errors arising from the standard deviation found in their respective testing measurements, and if those errors cannot be determined, then “about” may refer to, for example, within 5%, 4%, 3%, 2%, or 1% of the cited value.
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 invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 63514930 | Jul 2023 | US |
