METHOD OF IMPROVING PAPER MACHINE FABRIC PERFORMANCE

Abstract

Methods are provided for improving the papermaking process. In various embodiments, the methods include the application of alkali material in combination with an anionic polymeric dispersant and/or a hydroxyfunctional carboxylic acid to papermaking fabrics such that the application thereof removes contaminants from the papermaking fabrics and improves the drainage of said papermaking fabrics. Such alkali material in combination with an anionic polymeric dispersant and/or a hydroxyfunctional carboxylic acid can be applied as a single aqueous solution, and may further comprise a surfactant.

Claims

1. A method of treating papermaking fabrics comprising: applying an alkali material in combination with an anionic polymeric dispersant and/or a hydroxyfunctional carboxylic acid to the papermaking fabrics; wherein the application of the alkali material in combination with the anionic polymeric dispersant and/or the hydroxyfunctional carboxylic acid removes contaminants from the papermaking fabrics and improves the drainage of the papermaking fabrics.

2. The method of claim 1, wherein the papermaking fabrics are contaminated with wet soils in an amount from about 0.1 to about 100% by weight.

3. The method of claim 1, wherein the alkali material in combination with the anionic polymeric dispersant and/or the hydroxyfunctional carboxylic acid is applied as a single aqueous solution.

4. The method of claim 1, wherein the alkali material is selected from the group consisting of sodium hydroxide, potassium hydroxide, magnesium hydroxide, ammonia, sodium carbonate, sodium silicate, sodium phosphates, potassium phosphates, alcohol amines, and combinations thereof.

5. The method of claim 1, wherein the anionic polymeric dispersant is selected from the group consisting of polyacrylic acid and sulfonated analogs and salts thereof, polymaleic acid and sulfonated analogs and salts thereof, poly(maleic anhydride) and sulfonated analogs and salts thereof, polyphosphinocarboxylic acid and sulfonated analogs and salts thereof, polyglutamic acid and sulfonated analogs and salts thereof, polyfumaric acid and sulfonated analogs and salts thereof, polylacic acid and sulfonated analogs and salts thereof, carboxylated vinyl polymers and sulfonated analogs and salts thereof, copolymers of acrylic acid and maleic acid and sulfonated analogs and salts thereof, and combinations thereof.

6. The method of claim 3, wherein the aqueous solution comprises from about 1% to about 20% by weight anionic polymeric dispersant.

7. The method of claim 1, wherein the hydroxyfunctional carboxylic acid is an alpha hydroxyl acid.

8. The method of claim 6, wherein the alpha hydroxyl acid is selected from the group consisting of lactic acid, gluconic acid, glycolic acid, citric acid, mandelic acid, and potassium or sodium salts thereof.

9. The method of claim 3, wherein the aqueous solution comprises from about 1% to about 20% by weight hydroxyfunctional carboxylic acid.

10. The method of claim 1, further comprising applying a surfactant.

11. The method of claim 10, wherein the surfactant is selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, zwitterionic surfactants, and combinations thereof.

12. The method of claim 10, wherein the surfactant is selected from the group consisting of dodecylbenzene sulfonate, sodium-1-octane sulfonate, sodium caprylyl sulfonate, alcohol ethoxylates, and combinations thereof.

13. The method of claim 3, the aqueous solution further comprising a surfactant.

14. The method of claim 13, wherein the aqueous solution comprises from about 1% to about 20% by weight surfactant.

15. The method of claim 13, wherein the aqueous solution comprises from about 6% to about 18% by weight surfactant.

16. The method of claim 1, wherein the method further comprises applying one or more compounds selected from the group consisting of sodium hypocholorite, peroxides, triethanolamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, sodium silicate, tetrasdoium pyrophosphate, sodium tripolyphosphate, 1-(2,5-dimethoxy-4-methylphenyl)propan-2-amine, and combinations thereof.

17. The method of claim 3, wherein the aqueous solution further comprises one or more compounds selected from the group consisting of sodium hypocholorite, peroxides, triethanolamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, sodium silicate, tetrasdoium pyrophosphate, sodium tripolyphosphate, 1-(2,5-dimethoxy-4-methylphenyl)propan-2-amine, and combinations thereof.

18. The method of claim 1, wherein contaminants comprise organic contaminants.

19. The method of claim 1, wherein the papermaking fabrics comprise forming fabrics, press felt fabrics, and dryer fabrics.

20. The method of claim 3, wherein the aqueous solution has a pH from about 9.5 to about 13.5.

21. The method of claim 3, wherein the aqueous solution has a dynamic surface tension of about 25 to about 40.

22. The method of claim 3, wherein the aqueous solution is applied to the papermaking fabrics at a dosage of about 100 ppm to about 50,000 ppm while a papermaking machine is operating.

23. The method of claim 3, wherein the aqueous solution is applied to the papermaking fabrics at a dosage of about 0.1% to about 100% while a papermaking machine is not operating.

24. The method of claim 3, wherein the aqueous solution is applied to the papermaking fabrics through high pressure needle showers, fan showers, flooded nip showers, manual foaming equipment, or manual spraying equipment.

25. The method of claim 19, wherein the aqueous solution is applied to the papermaking fabrics continuously or intermittently.

26. The method of claim 3, wherein the aqueous solution is applied to the papermaking fabrics at a temperature from about 5 C. to about 60 C.

27. The method of claim 2, wherein the wet soils comprise of papermaking fibers and fines, hydrosols, hydrogels, or combinations thereof.

28. The method of claim 18, wherein the organic contaminants comprise of wet soils.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1A is a picture of the Drainage Test Unit used to conduct the Drainage Wash Study. FIG. 1B is a picture of the felt mounting rig clamp of the Drainage Test Unit.

[0017] FIG. 2 is a graph demonstrating that anionic polymeric dispersants and hydroxyfunctional carboxylic acids result in increased drainage rates of wash solutions passed through 3/4 press felt swatches when used with a caustic blend as compared to tap water and all other tested additives.

[0018] FIG. 3 is a graph demonstrating that anionic polymeric dispersants and hydroxyfunctional carboxylic acids result in increased drainage rates of triple tap water rinses after passing wash solutions through press felt swatches when used with a caustic blend as compared to tap water and all other tested additives.

[0019] FIG. 4 is a graph demonstrating that various concentrations of a 1:3 part mixture of anionic polymeric dispersants and hydroxyfunctional carboxylic acids result in increased drainage rates of wash solutions passed through press felt swatches when used with a caustic blend on press felt swatches loaded with either a low concentration of papermaking fines or a high concentration of papermaking fines.

[0020] FIG. 5 is a graph demonstrating that various concentrations of a 1:3 part mixture of anionic polymeric dispersants and hydroxyfunctional carboxylic acids result in increased drainage rates of triple tap water rinses after passing wash solutions through press felt swatches when used with a caustic blend on press felt swatches loaded with either a low concentration of papermaking fines or a high concentration of papermaking fines.

DETAILED DESCRIPTION

[0021] Reference will now be made in detail to various embodiments of a method of treating papermaking fabrics that results in the removal of contaminants from the papermaking fabrics and improves the drainage of the papermaking fabrics. The method includes the application of an alkali material in combination with an anionic polymeric dispersant and/or a hydroxyfunctional carboxylic acid to the papermaking fabrics. Embodiments of the methods can greatly reduce or eliminate the tendency of alkaline cleaners to cause fines swelling in papermaking fabrics. Thus, embodiments of the methods can greatly increase the utility of alkaline cleaners. Embodiments of the methods allow for alkaline cleaners to be used more effectively while the paper making machine is running. Embodiments also allow for the use of alkaline cleaners at higher concentrations, and further allow for the papermaking fabrics to be flushed and rinsed more easily thus ensuring that the paper machine returns to normal operating conditions more quickly. Additionally, embodiments allow for the contaminating wet soils, including papermaking fines, to be removed more effectively resulting in better water removal properties and better drainage of water through the papermaking fabric.

[0022] Unless otherwise indicated, the disclosure of any ranges in the specification and claims are to be understood as including the ranges itself and also anything subsumed therein, as well as endpoints.

[0023] In various embodiments, a method of treating papermaking fabrics includes applying an alkali material in combination with an anionic polymeric dispersant and/or a hydroxyfunctional carboxylic acid to the papermaking fabrics. The application of the alkali material in combination with the anionic polymeric dispersant and/or the hydroxyfunctional carboxylic removes contaminants from the papermaking fabrics and improves the drainage of the papermaking fabrics. In certain embodiments, the alkali the anionic polymeric dispersant and/or hydroxyfunctional carboxylic acid are applied to the papermaking fabrics separately from the alkali material. In other embodiments, the alkali material in combination with the anionic polymeric dispersant and/or hydroxyfunctional carboxylic acid are applied as a single aqueous solution to the papermaking fabrics.

[0024] The term papermaking fabrics as used herein with reference to various embodiments is intended to include, but not necessarily be limited to, papermaking felts such as press felt fabrics, forming fabrics, and dryer fabrics. In some embodiments, the papermaking fabrics comprise forming fabrics, press felt fabrics, and dryer fabrics. Additionally, the term drainage as used herein with reference to various embodiments is intended to include the drainage rate of the papermaking fabrics. The drainage rate can be calculated, for example, by the methods detailed in Example 1.

[0025] In some embodiments, the contaminants in the papermaking fabric include organic contaminants. In some embodiments, the contaminants include wet soils. In some embodiments, the papermaking fabrics are contaminated with wet soils in an amount from about 0.1 to about 100% by weight, including any value or ranges therebetween, as determined gravimetrically. The calculation for the wet soils is as follows: wet soils=wet weight of all papermaking contaminants/(dry weight of all papermaking contaminants+papermaking fabric). As described previously, wet soils include: papermaking fines, hydrosols, hydrogels, and various combinations thereof. Papermaking fines include, but not limited to, those derived from wood based pulp, recycled pulp and other cellulosic sources. Hydrosols include, but are not limited to: wet and dry strength resins, including but not limited to polyamideamine-epichlorohydrin and glyoxalated polyacrylamide; natural and modified starches; alkylketene dimer; alkyl succinic anhydride and rosin-based sizing; carboxyl methyl cellulose; guar gum; and retention aids, including but not limited to polyamines and polydadmacs. Hydrogels include, but are not limited to silicates, carbonates, and other inorganic fillers. In some embodiments, the papermaking fabrics are contaminated with papermaking fines in an amount from about 0.1 to about 100% by weight, including any value or ranges therebetween, as determined gravimetrically.

[0026] In various embodiments, the alkali material is selected from the group consisting of sodium hydroxide, potassium hydroxide, magnesium hydroxide, ammonia, sodium carbonate, sodium silicate, sodium phosphates, potassium phosphates, alcohol amines, and combinations thereof. In some embodiments, the alkali material is selected from sodium hydroxide, potassium hydroxide, and combinations thereof. Additionally, in certain embodiments, alkali material includes materials which have a pH range of from about 9.5 to about 13.5 when in a 1% solution.

[0027] According to various embodiments, the anionic polymeric dispersant is selected from the group consisting of polyacrylic acid and sulfonated analogs and salts thereof, polymaleic acid and sulfonated analogs and salts thereof, poly(maleic anhydride) and sulfonated analogs and salts thereof, polyphosphinocarboxylic acid and sulfonated analogs and salts thereof, polyglutamic acid and sulfonated analogs and salts thereof, polyfumaric acid and sulfonated analogs and salts thereof, polylacic acid and sulfonated analogs and salts thereof, carboxylated vinyl polymers and sulfonated analogs and salts thereof, copolymers of acrylic acid and maleic acid and sulfonated analogs and salts thereof, and combinations thereof. In various embodiments, the anionic polymeric dispersant is present in the single aqueous solution in an amount from about 1% to about 20% by weight based on the solids.

[0028] In various embodiments, the hydroxyfunctional carboxylic acid is an alpha hydroxyl acid. In some embodiments, the alpha hydroxyl acid is selected form the group consisting of lactic acid, gluconic acid, glycolic acid, citric acid, mandelic acid, and salts thereof, with more particular embodiments including potassium or sodium salts thereof. In various embodiments, the hydroxyfunctional carboxylic acid is present in the single aqueous solution in an amount from about 1% to about 20% by weight based on the solids.

[0029] In some embodiments, the method may further comprise applying a surfactant to the papermaking fabrics. In some embodiments, the surfactant is selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, zwitterionic surfactants, and combinations thereof. In some embodiments, the surfactant is selected from the group consisting of dodecylbenzene sulfonate, sodium-1-octane sulfonate, sodium caprylyl sulfonate, alcohol ethoxylates, and combinations thereof. In some embodiments, the single aqueous solution that is applied to the papermaking fabrics further comprises a surfactant. In various embodiments, the surfactant is present in the single aqueous solution in an amount from about 1% to about 20% by weight based on the solids. In other embodiments, the surfactant is present in the single aqueous solution comprising from about 6% to about 18% by weight based on the solids.

[0030] In some embodiments, the method may further comprise applying one or more compounds selected from the consisting of sodium hypocholorite, peroxides, triethanolamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, sodium silicate, tetrasdoium pyrophosphate, sodium tripolyphosphate, 1-(2,5-dimethoxy-4-methylphenyl)propan-2-amine, and combinations thereof. In some embodiments, the single aqueous solution can further comprise one or more compounds selected from the group consisting of sodium hypocholorite, peroxides, triethanolamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, sodium silicate, tetrasdoium pyrophosphate, sodium tripolyphosphate, 1-(2,5-dimethoxy-4-methylphenyl)propan-2-amine, and combinations thereof.

[0031] In some embodiments of the method, the single aqueous solution has a pH from about 9.5 to about 13.5. In other embodiments, the single aqueous solution has a dynamic surface tension of about 25 to about 40. In some embodiments, the aqueous solution is applied to the papermaking fabrics at a temperature from about 5 C. to about 60 C. In various embodiments, the aqueous solution is applied to the papermaking fabrics at a temperature from about 50 C. to about 55 C. In some embodiments, the aqueous solution is applied to the papermaking fabrics at a dosage of about 100 ppm to about 50,000 ppm while a papermaking machine is operating. In some embodiments, the single aqueous solution is applied to the papermaking fabrics at a dosage of about 0.1% to about 100% while a papermaking machine is not operating.

[0032] In various embodiments, the single aqueous solution is applied to the papermaking fabrics through high pressure needle showers, fan showers, flooded nip showers, manual foaming equipment, or manual spraying equipment. In more particular embodiments, the aqueous solution can be applied through such means to the papermaking fabrics either continuously or intermittently.

[0033] In order that various embodiments may be more readily understood, reference is made to the following examples which are intended to illustrate various embodiments, but not limit scope thereof.

Example 1

[0034] The drainage wash study method is designed to measure the ability of cleaning solutions to both remove soils and increase the water throughput of a tested felt swatch. The felts tested can be either dry or wet. Of note, if the test is run on a wet felt, only the water throughput mechanism can be measured. Felt swatches are cut into 1.5 diameter circles. If dry, these swatches are pre-weighed. Then, a swatch is fixed into the drainage column rig in the batt-base direction. The drainage column rig 1 is disclosed in FIG. 1A and FIG. 1B, and includes a solution column 2, a felt mounting rig clamp 4, an open/close ball valve 6, a vacuum control/monitor gauge 8, a vacuum pump 10, and a weight recording balance 12. The felt mounting rig clamp 4 further includes a felt swatch 14 and mounting screws 16 (FIG. 1B). The rig allows one to measure the weight of solution to pass through a specific area of the felt swatch 14 ( diameter) at specific time intervals (e.g. every four-tenths of a second).

[0035] The solutions can be set to run at various temperatures and/or vacuum. A number of solutions pass through the felt swatch 14 to generate the drainage rate data, and the solutions in which the drainage is measured include the initial drainage rate of the felts swatch 14 to determine its post-mortem state, the product solution drainage rate and the water rinse drainage rate. After the sequence of washes is complete, the felt swatch 14 is removed from the rig 1, is dried, and then reweighed. The results of the test are measured as the increase in drainage rate through the washing and rinsing compared to the initial swatch data and the percent soils removal based on the known amount of soils in the felt compared to the weight loss of the felt swatches. The results are based on an average of felt swatches per each test codeeach series of swatches cut in the machine direction.

Example 2

[0036] Exemplary results of the Drainage Wash Study are shown below in Table 1 (using Virgin Tissue Machine) and Table 2 (using Recycle Tissue Machine).

TABLE-US-00001 TABLE 1 Drainage Wash Study Method of Various Additives (Virgin Tissue Machine) Drainage Rate Measurements Only product wash triple rinse above caustic blend wo/caustic blend w/caustic blend wo/caustic blend propylene glycol 1.690 0.825 0.324 2.331 polycarboxylate copolymer 15.194 0.754 9.350 2.226 nonionic blend 2.801 0.987 0.391 3.973 sulfonate blend 1.605 0.658 4.897 4.539 polyhydroxy carboxylate 19.006 0.397 13.612 4.051

TABLE-US-00002 TABLE 2 Drainage Wash Study Method of Various Additives (Recycle Tissue Machine) Drainage Rate Measurements Only product wash triple rinse above caustic blend wo/caustic blend w/caustic blend wo/caustic blend propylene glycol 3.305 0.514 0.417 2.907 polycarboxylate copolymer 12.301 2.412 2.994 0.537 nonionic blend 5.272 0.296 0.322 0.259 sulfonate blend 9.841 1.312 5.207 0.832 polyhydroxy carboxylate 13.279 0.216 5.962 1.653

[0037] As can be seen from Table 1 and Table 2, an anionic polymeric dispersant (polycarboxylate copolymer) and a hydroxyfunctional carboxylic acid (polyhydroxy carboxylate) result in increased drainage rates when used with a caustic blend as compared to tap water alone and all other tested additives. The tables depict the drainage rate slope change (%) using both a product wash and a triple rinse, both with a caustic blend and without a caustic blend.

Example 3

[0038] Additional data from the Drainage Wash Study confirmed that anionic polymeric dispersants (maleic anhydride) and hydroxyfunctional carboxylic acids (glucoheptonate) result in increased drainage rates of when used with a caustic blend as compared to tap water and all other tested additives. As can be seen in FIG. 2 and FIG. 3, maleic anhydride and glucoheptonate resulted in increased drainage rates of solutions passed though press felt swatches using the Drainage Wash Study Method. These specific examples used a 15 Hg vacuum, a 120 F. wash temperature, and tap water. The data of FIG. 2 depicts the drainage rate slope change (%) of wash solutions passed through press felt swatches. The data of FIG. 3 depicts the drainage rate slope change (%) of triple tap water rinses after passing wash solutions through press felt swatches.

Example 4

[0039] Additional data from the Drainage Wash Study demonstrates that various concentrations of a 1:3 part mixture of anionic polymeric dispersants (maleic anhydride) and hydroxyfunctional carboxylic acids (glucoheptonate) result in increased drainage rates of when used with a caustic blend on press felt swatches loaded with either a low concentration of papermaking fines or a high concentration of papermaking fines. As can be seen in FIG. 4 and FIG. 5, maleic anhydride and glucoheptonate resulted in increased drainage rates of solutions passed though press felt swatches using the Drainage Wash Study Method. These specific examples used a 15 Hg vacuum, a 120 F. wash temperature, and tap water. The data of FIG. 4 depicts the drainage rate slope change (%) of product wash solutions passed through press felt swatches that were pre-loaded with either low papermaking fines (0.71%) or high papermaking fine (3.96%). Additionally, the data from FIG. 4 demonstrates that at certain concentrations, the addition of surfactants to the mixture of anionic polymeric dispersants and hydroxyfunctional carboxylic acids can further increase the drainage rate of wash product solutions. The data of FIG. 5 depicts the drainage rate slope change (%) of triple tap water rinses after passing wash solutions through press felt swatches that were pre-loaded with either low papermaking fines (0.71%) or high papermaking fine (3.96%). Additionally, the data from FIG. 5 demonstrates that at certain concentrations, the addition of surfactants to the mixture of anionic polymeric dispersants and hydroxyfunctional carboxylic acids can further increase the drainage rate of triple tap water rinses after passing wash solutions through press felt swatches that were pre-loaded with either low papermaking fines (0.71%) or high papermaking fine (3.96%).

[0040] Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modifications and variations come within the scope of the appended claims and their equivalents.