MXPA97005451A - Functional coatings for paper machine fabrics and a method for covering mis - Google Patents

Abstract

The present invention relates to fabrics for papermaking machines that are made resistant to contamination, maintain good permeability and have improved seam strength as a result of a durable coating that lasts the life of the fabric. A polyurethane-based coating containing a fluorochemical will last the entire life of the fabric. It has been found that optical brighteners and titanium dioxide also improve the appearance of the

Description

^ "FUNCTIONAL COATINGS FOR PAPER MACHINE FABRICS AND A METHOD FOR COATING THEM" FIELD OF THE INVENTION The present invention is directed to fabrics for papermaking machines that are made from contamination resistant, maintain good permeability and improved seam strength as a result of a durable coating that lasts the entire life of the fabric.

BACKGROUND OF THE INVENTION The current paper manufacturer employs a highly sophisticated papermaking machine which is, in essence, an apparatus for removing water from the paper sample. The water is removed in three stages or sequential sections of the machine.

In the first section or former, the sample is deposited on a mobile forming fabric and the water is drained through the fabric to leave a sheet of paper or pulp having a solids content of about 18 to 25 percent. weight. The formed paste is transported to a cloth press section and passes through one or more pressure point presses on a moving press fabric to remove enough water to form a sheet having a solids content of about 36 to 50 weight percent. This sheet is then transferred to the dryer section of the papermaking machine where the Drying fabrics keep the paper sheet against hot steam drying cylinders to obtain about 92 to 96 percent solids content. The fabrics of the paper machine used in the papermaking machine must develop a wide range of functions according to the position of the machine, i.e., forming section, dryer or press section. The forming fabrics used in the papermaking process are of a kind of papermaking fabric that are used in the section of a papermaking machine. Generally, the forming fabrics are constructed of synthetic strands joined together, commonly by fabric in a fabric construction characterized by a high degree of open spaces between the intersecting strands. The forming fabrics must maintain a high degree of opening to ensure that they allow the removal of water from the slurry of fiber deposited therein. Because the ability to remove water is a critical function of the forming fabric, it is necessary to ensure that the fabric retains a high degree of openness throughout its life. However, the degree of opening of a fabric is continuously reduced during its life. In addition, the pulp of fiber, the pulp of paper, generally contains additives such as re-fillers of clay, tar and polymeric materials that narrow the open spaces of the fabric. The use of recycled fibers has introduced considerable amounts of contaminants in the form of dyes, adhesives, tars and polymeric materials, which also narrow the open spaces of the fabric. In addition, fabric forming designs now include multiple layer fabrics that are more susceptible to contamination problems. Accordingly, it is desirable to provide a fabric exhibiting an improved degree of resistance to contamination. A proposed solution of the prior art is the use of re-sisting strands to contamination in the construction of the fabric. This has not proved to be completely satisfactory because the resistance to contamination provided by these strands is short-lived and / or inefficient. Another proposed solution proposes coating or treating the fabric of the paper machine in order to improve the resistance to contaminants. Again, this method was not successful enough because the resistance to contamination provided by the coating is short-lived and / or inefficient. A problem inherent in coatings or treatments is that coatings per se are known to reduce permeability in a fabric, an undesired result that inhibits water removal capacity, the main function of a forming fabric. Therefore, it is important that any coating applied to a forming fabric reduces the permeability as little as possible.

It is also desirable to improve the shear stability of a paper machine fabric. Shear stability is the degree to which the filaments of the fabric can be changed before the opposing filaments secure them in position. U.S. Pat. No. 5,207,873 discloses a coating for papermaking fabrics in order to make them contamination proof, by increasing the anti-stick properties of the fabric. The fabric is treated with a solution containing 1% solids containing poly (tetrafluoroethylene), urethane copolymer, polyacrylamide, acrylic copolymer, methylene bisa-crilamide, polyaziridine binding agent, pyro-lidone methyl, persulfate solution of ammonium, sodium me-tabisulfate solution, urea peroxide solution, and silver nitrate solution, the components are present in the coating in amounts and concentrations established in the discovery. This coating has not proven to be totally effective and / or permanent on the fabrics of the paper machine. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a fabric used in the forming, press or drying section of a paper machine that exhibits improved resistance to contamination throughout the life of the fabric. It is also another object of the invention to provide a coating that improves the durability of the fabric. It is also another object of the invention to provide a coating that improves the shear stability of the fabric. It is also another object of the invention to provide a coating that improves the strength of the seam of the fabric. It is also another object of the invention to provide a coating that does not significantly affect the permeability of the fabric. It is also another object of the invention to provide a coating applied in thin layers of low weight. It is also another object of the invention to provide a coating for a fabric used in a paper machine that achieves the aforementioned objects. The present invention is a coated fabric used in a paper machine that has a significantly improved resistance to contamination that lasts the entire life of the fabric. In another aspect, the invention is a method of coating a used fabric in a paper machine to improve its resistance to contamination. The coating discovered here has been shown to substantially improve the resistance to contamination of the coated fabrics, while not significantly reducing the permeability of the fabric, and does not increase the fabric mass to a significant degree. That is, the present invention provides a thin, light weight coating for the paper machine sheets that adds additional mass limited to the fabric. In another aspect of the invention, the coating has been shown to increase the strength of the seam of the fabric. In another aspect of the invention, the coating has been shown to increase the shear stability of a fabric. In this way, the coating that is applied in thin layers improves the aforementioned properties by improving the execution of the fabric. Applicants have found that a polyurethane-based coating containing a fluorochemical will render the fabric resistant to contaminants. It has been found that optical brighteners and titanium dioxide also improve the appearance of the fabric. DETAILED DESCRIPTION OF THE PREFERRED INCORPORATION The materials suitable for use in the coating of the present invention are described below. Some different polyurethane materials may be used in the present invention. Among the commercially available products, suitable polyurethanes include water-based urethanes such as Carver Tripp Super polyurethane available from Parks Corp., Fall River, MA, USA, Bayhydrol 123 from Mobay Chemical, Inc., and Permutane® from ICI Chemicals, Ltd. Suitable fluorochemicals include water dispersible polymer materials, such as: FC 722 or FC 724 3M (perfluorinated acrylates), Bureo® PEL SRF, and Bureo ® PEL 5556, available from Burlington Chemical Co., Inc., Burlington, NC; Zonyl® FS-300 (substituted monoether of fluoroalkyl alcohol with polyethylene glycol, available from DuPont), Zonyl® 8300 (fluorinated acrylic), Zonyl® (fluoroalkylacrylate, fluoroalkylmethacrylate) intermediates, aqueous dispersions of poly (tetrafluoroethylene), (Teflon®, available from DuPont, Fluon®, available from ICI, Ltd., and Xylan® 300, available from Hitford Corp., West Chester PA.), aqueous dispersions of poly (chlorotrifluoroethylene) (Aclar®, available from Allied Signal, Inc.) aqueous dispersions of ethylene propylene (FEP), (available from DuPont as Teflon® and Xylan® 1700 series, available from Whitford Corp.), aqueous dispersions of perlfluoroalkoxy (PFA, available as Teflon® PFA and Xylan® 1700 series from Whitford Corp.), fluorinated polyurethanes as fluorinated diol intermediates with diisocyanates, polymeric fluoro-surfactants such as fluorinated alkyl esters (such as Fluorad® FC-430, FC-431, FC-740 available from 3M and Zonyl available from DuPont), substituted monoether of fluoroalkyl alcohol with polyethylene glycol (available as Zonyl® FS-300 from DuPont), and perfluoroalkyl acrylate or methacrylate copolymers. Suitable optical brighteners include products available under the trademark Blankophor from Bayer AG, Leverkusen, Germany, such as Blankophor SOL, (BenzoPyranone), Blankophor P167, (disulfonic stilbene acid, sodium salt derivatives), as well as 2, 2 '- (1,2-etenediyl) bis (, 1-phenylene) bisbenzoxazole available from Eastern Chemical Company as Eastobrite OB-1. Optical brighteners are well-known additives for thermoplastics and other materials that reduce yellowing and improve whiteness and improve the gloss of the product. Titanium dioxide (Ti02) is available from Aldrich. A particularly suitable combination for a coating is Carver Tripp Superpolyurethane, Bureo PEL 5556, Blankophor P167 optical brightener, and titanium dioxide. The Bureo PEL SRF and Bureo PEL 5556 are copolymers of perfluoroalkyl acrylates or methacrylates in solution. Efficient contamination-resistant fabrics have been prepared in such a way that the coating of the fabric does not contain thinners such as water or other solvents. However, a greater degree of the original permeability of the coated fabric is retained when the solids content of the coating is reduced. Water is a preferred diluent because of its low cost and because it is compatible with water-based polyurethanes. It has been found that fabrics coated with coatings having a solids content of about 10 to 15% (w / w) maintain a high degree of their original permeability, that is, of the order of about 90-99% of their original permeability This means that the permeability is reduced only about 1% to 10% as a result of the coating. It has been found that the preferred solids content is about 10-15%. The fabrics can be coated in any conventional manner, including immersion within a coating bath, knife or bar coating techniques, sweeper coating, transfer coating, spray or applicator or contact roller, slot applicator and applicator. brush. The application with a contact roller has been effective. The coating can be applied with a single pass or it can be applied in multiple passes. The subsequent procedure requires removing the excess material and then drying or setting the coating as indicated by the manufacturer of the particular material. These methods are well known by those skilled in technology. The following examples illustrate the invention and its application. Examples 1-21 Twenty one coating combinations containing one or more of the following were prepared: Polyurethane: Carver Tripp Superpoly; Fluorochemical: 1) Bureo PEL SRF; 2) Bureo PEL 5556, Optical brightener: 1) Eastobrite OB-1; 2) Blankophor SOL; 3) Blankophor P167, Optical brightener improver: 1) Ti-tanium dioxide (Ti02). Each of the twenty-one coatings is applied to a fabric in three separate locations referred to as marks. The fabric ran on a high speed newspaper printing machine that has presented problems of contamination of the sample without ink. The compositions of Examples 1-21 are set forth below in Table I. All brands showed improved resistance to contamination, Example 12 showed the best results. The marks exhibited resistance to contamination during the entire life of the fabric, the fabric was worn eighty four (84) days.

TABLE 1 Ex. Brands Polyrethane% _ Fluorochemical _% Optical brightener% Other _% 1 24 36 61 SuperPoly 90 Bureo PEL SRF 9.5 Eastobrite OB-1 0.5 2 23 35 37 SuperPoly 90 Bureo PEL SRF 9.5 Blankophor SOL 0.5 3 9 33 57 SuperPoly 90 Bureo PEL SRF 9.5 Blankophor P167 0.5 4 5 8 58 SuperPolu 90 Bureo PEL5556 9.5 Eastobrite OB-1 0.5 '5 30 38 63 SuperPoly 90 Bureo PEL5556 9.5 Blankophor SOL 0.5 6 21 29 55 SuperPoly 90 Bureo PEL5556 9.5 Blankophor 167 0.5 7, 6 31 46 SuperPolly 90 Bureo PEL SRF 9 Eastobrite OB-1 0.5 Ti02 0.5 8 12 13 17 SuperPoly 90 Bureo PEL SRF 9 Blankophor SOL 0.5 Ti02 0.5, 9 14 15 56 SuperPoly 90 Bureo PEL SRF 9 Blankophor P167 0.5 Ti02 0.5 10 2 39 59 SuperPoly 90 Bureo PEL5556 9 Eastobrite OB-1 0.5 Ti02 0.5 11 1 20 41 SuperPoly 90 Bureo PEL5556 9 Blankophor SOL 0.5 Ti02 0.5 12 3 28 48 SuperPoly 90 Bureo PEL5556 9 Blankophor P 167 0.5 Ti02 0.5 13 22 43 44 SuperPoly 95 Bureo PEL SRF 5 14 10 16 49 SuperPoly 91 Bureo PEL SRF 9 15 4 45 51 SuperPoly 87 Bureo PEL SRF 13 16 11 26 42 SuperPoly 83 Bureo PEL SRF 17 17 18 34 50 SuperPoly 95 Bureo PEL5556 5 18 532 40 60 SuperPoly 91 Bureo P EL5556 9 19 25 54 62 SuperPoly 87 Bureo PEL5556 13 20 19 27 53 SuperPoly "83 Bureo PEL5556 17 21 7 47 52 SuperPoly 100 Example 22 The following coating was prepared using the components of Example 12. 55 gal. SuperPoly polyurethane; 10 gal. fluorochemical Bureo PEL 5556; 20 grams of Blankophor P167 optical brightener; 650 grams Ti02. Blankophor and Ti02 were mixed in a 5-gallon bucket containing water and then the other components were added. Then, the 25 gallons of the coating described in this example were diluted with 25 gallons of water at a 50% concentration containing approximately 14% solids. The coating and the water were mixed vigorously in a mixing apparatus. Some applications were made using a concentration of either 100% or 50%, on two Sensotex® triple-ply cloth and Duotex® double ply fabric, both available from Albany International Corp., Albany, NY. The fabrics were analyzed to determine the permeability before and after the coating. The data is presented below in Table 5. All coatings were applied with a contact roller applicator. The application conditions were 1.75 KN / M, 4M / min, .034 bar vacuum.

TABLE 5 Perm number Air Decrease Fall in CFM Coatings ^ (cfm) Duotex® Before treatment 473,468 0 0 100% 3 410,415 12.3 31.5 50% 2 448,461 3.4 16 50% 3 456,451 3.6 17 50% 4 448,443 5.3 25 Sensotex® Before Treatment 535,537 0 0 100% 3 491,491 8.4 45 50% 2 524,526 2.1 11 50% 3 517,515 3.7 20 50% 4 513,511 4.1 24 Example 22 A solution of 10% solids was prepared from the coating of example 12. The appropriate proportions for a re-coating containing 10% solids are: 20 gallons of Carver Tripp SuperPoly 40 gallons of water 3 1/3 gallons of Bureo PEL 5556 6 2/3 gallons of Eastobrite OB-l 226 g. of Ti02 The coating was applied as stated previously in the previous examples. The coated fabrics were analyzed for the purpose of determining whether the coating improved the strength of the seam. It was found that the re-coated samples improved the seam strength, in the order of about 45 pli, or about 25% on an uncoated fabric. The results are set forth in Table 6. The shear of the fabric was also reduced to an almost unmeasured amount after coating as set forth in Table 7. TABLE 6 MULTIPLE LAYER COATING WITH 10% SOLID COATING RESISTANCE SEWING (PLI) Uncoated 1 181.31 Uncoated 2 177.48 Uncoated average 179.4 Treaty 1 233.5 Treaty 2 217.71 Treaty 3 233.66 Average Treaty 224.8 As recorded in Table 7, the shear stability of the strands of the fabric is indicated in a table where a sample of fabric measuring 250 mm x 250 mm, moves in the direction of the machine in order to determine the distance moved before the buckling of the fabric. Then the fabric moves in the opposite direction. The total of the two measurements divided by the total length of the sample and multiplied by 100 is added, in order to provide the shear stability expressed as a percentage of the length in the machine direction. The fabric is rotated and the same marking is made for the shear stability of the strands of the transverse direction of the machine.

TABLE 7 TRIPLE LAYER FABRIC Shear MD Shear CD TEST POLYURETHANE BEFORE AFTER BEFORE AFTER COATING RECOVERY COATING RECUBRIMENT AND BATH AND BATH 1 Parks Superpoly Satin - 30% Solids 4% 0% 2 Parks SuperPoly Satin - 15% Solids 4% 12- 4% 3 Parks SuperPoly Brillo - 30% Solids 4% 0% 4% 4 Parks SuperPoly Brillo - 15% Solids 4% 4% 5 Parks SuperPoly Sealer - 24% Solids 4% 1% 4% The shear is measured as a free movement of a sample of 250 mm. Bathing took place at 400 psi for 8 hours with .040"oscillating needle showers EXAMPLE 24 Two forming fabrics, each of the positions of a twin wire forming the machine, were coated with a 10% solids coating described in Example 23 above, and run on a newspaper printing machine. high speed. The sample consisted of 20% recirculated reserve and no ink. High-pressure shower heads were used on the fabrics. The transformed fabric was exposed to 300-475 psi showers. The backing cloth was exposed to 250-300 psi showers. Running on the newspaper printing machine, the fabrics were exposed to tar, ink and fillers. The fabrics ran together for 91 days, which is the expected average life of the fabrics. Viewed under a microscope, it was evident that tar and filler were absent on the surface of the fabric, indicating that the coating was retained on the fabric during its entire life, and was not removed, despite exposure to showers high pressure. The coating was still visible at the intersection on the points. In this example, the contamination resistance provided by the coatings eliminates the need to use cleaning chemicals in the fabrics, resulting in substantial savings for the paper manufacturer. Figure 1 is a photograph of the coated fabric (transformed fabric) after it has been removed from the machine. There is an absence of contaminants on the surface of the fabric. Figure 2 is a photograph of a fabric of the same design of the fabric of the invention shown in Figure 1. The fabric of Figure 2 was not coated and ran in the same machine for 84 days and exposed to the same conditions. In the photograph, the presence of contaminants in the fabric is evident. EXAMPLE 25 A coating of 30% solids containing the components of Example 23 was prepared. The coating was applied in three separate sections as indicated above in the previous examples. After each coating, the cloth was dried and set. Prior to the application of the first coating and after applying each coating layer, the air permeability, mass added per coating layer, machine direction shear, and transverse direction shear of the fabric machine were determined. . The coating was diluted with water to reduce the solids content to 10% and was subjected in order to indicate the physical properties described above. The mass samples were cut from the bands in circular patterns measuring 2"(0.0508 m) in diameter, it was found that after the first application of the coating at 10% solids, the average mass added was 3.62 g / m2 or 0.87% (w / w) After the first application of the coating at 30% solids, the average mass added was 9.37 g / m2, or 2.28% (w / w) .The additional layers will increase the coating mass added to the fabric EXAMPLE 26 A forming fabric was run on a pilot paper pulp machine consisting of 100% old corrugated container (OCC) Four different coatings were applied to the fabric. - uncoated control, B - Carver Tripp Superpolyurethane with Bureo® PEL 5556 (10% solids), C - Carver Tripp Superpolyurethane, Bureo® PEL 5556, and Blankophor P167 optical brightener (10% solids); D - Superpolyurethane Carver Tripp, Bureo® PEL 5556, Blankophor P167 optical brightener, and TÍ02 (10% solids). The fabric was run for 3 days at speeds with limits of 1500-2200 feet / min. 200 psi needle baths were used without cleaning chemicals. After the test, the fabric was removed and a contamination analysis was performed on each area. Figure 3 is a photograph of an uncoated fabric (A) taken at a 5X amplification, and Figure 4 is a photograph of coating B (at a 5X magnification). Photographs of the fabrics were also taken with coatings C and D. All the photographs were tracked inside a computer with a gray scale. With the Microsoft Paintbrush program, the pollutants were colored with blue. The gray fabric was removed from the image leaving only the blue. This image was loaded into another program that counted the blue pixels and found a% contaminated area. Figures 5 and 6 are the colored contaminated images of the tiles with the A and B coatings that were used for pixel counting. The results are listed below: COATING% POLLUTION A 4.1 B 0.9 C 1.1 D 1.4

Claims (75)

1. NOVELTY OF THE INVENTION Having described the invention, it is considered as a novelty, and therefore, the content of the following clauses is claimed as property. CLAUSES 1. A fabric of the paper machine for use in the forming, press or dryer section of a papermaking machine, which consists of a cloth coated with at least one layer of a urethane-based coating that with -It essentially consists of a fluorochemical, where the fabrics exhibit an improvement in the resistance to contamination.
2. 2. The fabric of the paper machine of clause 1, wherein the fluorochemical is a fluoro-substituted, polymeric material that is dispersed in water selected from the group consisting of perfluorinated acrylates, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol , fluoroalkylated acrylic, fluoroalkylacrylate, fluoroalkylmethacrylate, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous perfluoroalkoxy dispersions, fluorinated polyurethanes, fluorinated alkyl esters, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol, and acrylate copolymers or perfluoroalkyl methacrylates.
3. 3. The fabric of the paper machine as set forth in clause 1, wherein the coating also consists of an optical brightener and a bleach.
4. 4. The fabric of the paper machine of clause 1, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulphonic acid, sodium salt derivative, and 2, 2 '- (1, 2-etenedil) bis (4,1-phenylene) bisbenzoxazole.
5. 5. The fabric of the paper machine as set forth in clause 4, wherein the bleach is titanium dioxide.
6. 6. The fabric of the paper machine of clause 1, where the polyurethane is a water-based polyurethane.
7. 7. The fabric of the paper machine as set forth in clause 1, wherein the coating consists of 5-30% solids based on weight.
8. 8. The fabric of the paper machine as set forth in clause 1, wherein the coating consists of 10-15% solids based on weight.
9. 9. The fabric of the paper machine of clause 1, wherein the coating is applied in at least two layers.
10. 10. The fabric of the paper machine of clause 1, wherein the mass added to the fabric by the coating is within the limit of 0.5% to 5% per application based on the weight of the uncoated fabric.
11. 11. The fabric of the paper machine as set forth in clause 1, where the coated tola is forged.
12. 12. The fabric of the paper machine as set forth in clause 1, wherein the fabric is a single layer fabric.
13. 13. The fabric as set out in clause 1, where the fabric is a multi-layered fabric.
14. A fabric of the paper machine for use in the forming, pressing or drying section of a paper machine, which consists of a fabric coated with at least one layer of a urethane-based coating, consisting essentially of of a fluorochemical, wherein the fabrics exhibit an improvement in the resistance to contamination and an improvement in either the strength of the seam, shear stability, or both, when compared to uncoated fabrics.
15. 15. The fabric of the paper machine of clause 14, wherein the fluorochemical is a fluoro-substituted, polymeric material that is dispersed in water selected from the group consisting of perfluorinated acrylates, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol, acrylic fluoro-nated, luoroalkylacrylate, fluoroalkylmethacrylate, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous perfluoroalkoxy dispersions, fluorinated polyurethanes, fluorinated alkyl esters, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol, and acrylate copolymers or perfluoroalkyl methacrylates.
16. 16. The fabric of the paper machine as set forth in clause 14, wherein the coating further comprises an optical brightener and a bleach.
17. 17. The fabric of the paper machine of clause 14, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulfonic acid, sodium salt derivative, and 2, 2 '- (1, 2- etenedil) bis (4,1-phenylene) bisbenzoxazole.
18. 18. The fabric of the paper machine as set forth in clause 18, wherein the bleach is titanium dioxide.
19. 19. The fabric of the paper machine of clause 14, wherein the polyurethane is a water-based polyurethane.
20. 20. The fabric of the paper machine as set forth in clause 14, wherein the coating consists of 5-30% solids based on weight.
21. 21. The fabric of the paper machine as set forth in clause 14, wherein the coating consists of 10-15% solids based on weight.
22. 22. The fabric of the paper machine of clause 14, wherein the coating is applied in at least two layers.
23. 23. The fabric of the paper machine of clause 14, wherein the mass added to the fabric by the coating is within the limit of 0.5? > at 5% per application cn basis to the weight of the uncoated fabric.
24. 24. The Lela of the paper machine as set forth in clause 14, where the coated fabric is forged.
25. 25. The fabric of the paper machine as set forth in clause 14, wherein the fabric is a simple layer fabric.
26. 26. The fabric as set forth in clause 14, wherein the fabric is a multi-layered fabric.
27. 27. A fabric of the contamination-resistant paper machine for use in the forming, press or drying section of a papermaking machine, which consists of a fabric coated with a coating consisting essentially of a polyurethane, a fluorochemical and an optical brightener.
28. 28. The fabric of the paper machine of clause 27, wherein the fluorochemical is a fluoro-substituted, polymeric material that is dispersed in water selected from the group consisting of perfluorinated acrylates, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol , fluorinated acrylic, fluoroalkylacrylate, fluoroalkylmethacrylate, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous perfluoroalkoxy dispersions, fluorinated polyurethanes, fluorinated alkyl esters, substituted monoethers of fluoroalkyl alcohol with polyethylene glycol, and copolymers of perfluoroalkyl acrylates or methacrylates.
29. 29. The fabric of the paper machine of clause 27, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulfonic acid, sodium salt derivative, and 2, 2 '- (1, 2- etenedil) bis (4,1-phenylene) bisbenzoxazole.
30. 30. The fabric of the paper machine as set forth in clause 27, wherein the bleach is further constituted of titanium dioxide.
31. 31. The fabric of the paper machine of clause 27, where the polyurethane is a water-based polyurethane.
32. 32. The fabric of the paper machine as set forth in clause 27, wherein the coating consists of 5-30% solids based on weight.
33. 33. The fabric of the paper machine as set forth in clause 27, wherein the coating consists of 10-15% solids based on weight.
34. 34. The fabric of the paper machine of clause 27, wherein the coating is applied in at least two layers.
35. 35. The fabric of the paper machine of clause 27, wherein the mass added to the fabric by the coating is within the limit of 0.5% to 5% per application based on the weight of the uncoated fabric.
36. 36. The fabric of the paper machine as set out in clause 27, where the coated fabric is forged.
37. 37. The fabric of the paper machine as set out in clause 27, where the fabric is a simple layer fabric.
38. 38. The fabric as set out in clause 27, where the fabric is a multi-layered fabric.
39. 39. A fabric of the contamination-resistant paper machine for use in the forming, pressing or drying section of a papermaking machine, consisting of a fabric covered with a coating consisting essentially of a polyurethane, a fluorochemical, an optical brightener and a bleach.
40. 40. The fabric of the paper machine of clause 39, wherein the fluorochemical is a fluoro-substituted, polymeric material that is dispersed in water selected from the group consisting of perfluorinated acrylates, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol, acrylic fluorinated, fluoroalkylacrylate, fluoroalkylmethacrylate, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous perfluoroalkoxy dispersions, fluorinated polyurethanes, fluorinated alkyl esters, substituted monoethers of fluoroalkyl alcohol with polyethylene glycol, and copolymers of perfluoroalkyl acrylates or methacrylates.
41. 41. The fabric of the paper machine of clause 39, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulphonic acid, sodium salt derivative, and 2, 2 '- (1, 2-etenedil) bis (4,1-phenylene) bisbenzoxazole.
42. 42. The fabric of the paper machine as set forth in clause 39, wherein the bleach is titanium dioxide.
43. 43. The fabric of the paper machine of clause 39, where the polyurethane is a water-based polyurethane.
44. 44. The fabric of the paper machine as set forth in clause 39, wherein the coating consists of 5-30% solids based on weight.
45. 45. The fabric of the paper machine as set forth in clause 39, wherein the coating consists of 10-15% solids based on weight.
46. 46. The fabric of the paper machine of clause 39, wherein the coating is applied in at least two layers.
47. 47. The fabric of the paper machine of clause 39, wherein the mass added to the fabric by the coating is within the limit of 0.5% to 5% per application based on the weight of the uncoated fabric.
48. 48. The fabric of the paper machine as set forth in clause 39, wherein the coated fabric is forged.
49. 49. The fabric of the paper machine as set forth in clause 39, wherein the fabric is a simple layer fabric.
50. 50. The fabric as set forth in clause 39, wherein the fabric is a multi-layered fabric.
51. 51. A fabric of the pollution-resistant paper machine for use in the forming, pressing or drying section of a papermaking machine, which consists of a fabric coated with a coating consisting essentially of a polyurethane, a fluorochemical and a brightener optical; wherein the resistance to contamination is exhibited during the life of the fabric and the fabric exhibits a reduction in air permeability not greater than 10%.
52. 52. The fabric of the paper machine of clause 51, wherein the mico fluoroqu.i is a fluoro-do their titui, polymeric material water dispersible selected from the group consisting of perfluorinated acrylates, fluoroalkyl substituted monoether alcohol glycol polyethylene, fluorinata-do acrylic, fluoroalkylacrylate, fluoroalkylmethacrylate, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous perfluoroalkoxy dispersions, fluorinated polyurethanes, fluorinated alkyl esters, substituted monoeter of fluoroalkyl alcohol with polyethylene glycol, and copolymers of perfluoroalkyl acrylates or methacrylates.
53. 53. The fabric of the paper machine of clause 51, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulfonic acid, sodium salt derivative, and 2, 2 '- (1, 2- etenedil) bis (, 1-phenylene) bisbenzoxazole.
54. 54. The fabric of the paper machine as set forth in clause 51, wherein the bleach is titanium dioxide.
55. 55. The fabric of the paper machine of clause 51, where the polyurethane is a water-based polyurethane.
56. 56. The fabric of the paper machine as set forth in clause 51, wherein the coating consists of 5-30% solids based on weight.
57. 57. The fabric of the paper machine as set forth in clause 51, wherein the coating consists of 10-15% solids based on weight.
58. 58. The fabric of the paper machine of clause 51, wherein the coating is applied in at least two layers.
59. 59. The fabric of the paper machine of clause 51, wherein the mass added to the fabric by the coating is within the limit of 0.5% to 5% per application based on the weight of the uncoated fabric.
60. 60. The fabric of the paper machine as set forth in clause 51, wherein the coated fabric is forged.
61. 61. The fabric of the paper machine as set out in clause 51, where the fabric is a simple layer fabric.
62. 62. The fabric as set out in clause 51, where the fabric is a multi-layered fabric.
63. 63. A method of imparting resistance contaminates-ing fabrics paper machine comprising the steps of applying to the fabric at least one coating layer consisting essentially of a polyurethane, a fluorochemical, and an optical brightener , and a bleach, and the drying of the coated fabric.
64. 64. The method of clause 63, wherein the fluorochemical is a fluoro-substituted polymeric material dispersion-ble in water selected from the group consisting of perfluorinated acrylates, fluoroalkyl substituted monoether alcohol polyethyleneglycol, fluorinated acrylic, fluoroalquila-crilato , fluoroalquilmetacrilato, aqueous dispersions of fluoro-substituted polyolefins, aqueous dispersions of fluorinated ethylene propylene, aqueous dispersions of perfluo-roalkoxi, polyurethanes fluorinatados, alkyl esters fluorinatados monoether substituted fluoroalkyl alcohol with polyethylene glycol, and copolymers of acrylates or methacrylates perfluoroalkyl.
65. 65. The method 63, wherein the optical brightener is selected from the group consisting of BenzoPyranone, stilbene disulfonic acid, sodium salt derivative, and 2,2'- (1, 2etenedil) bis (4, 1-phenylene) Bisbenzoxazole
66. 66. The method as set forth in clause 63, wherein the bleach is titanium dioxide.
67. 67. The method of clause 63, where the polyurethane is a water-based polyurethane.
68. 68. The method of clause 63, where the coated Lela is forged.
69. 69. The method as set forth in clause 63, wherein the coating is applied to the fabric one or more times.
70. 70. The method as set forth in clause 63, where the coating contains 5-30% solids.
71. 71. The method as set forth in clause 63, where the coating contains 10-15% solids.
72. 72. The method as set forth in clause 63, wherein the fabric is used in the forming, press or drying section of a paper machine.
73. 73. The method as set forth in clause 63, wherein the fabric is a single layer fabric.
74. 74. The method as set forth in clause 63, wherein the fabric is a multi-layered fabric.
75. 75. The method of clause 63, wherein the mass added to the fabric by the coating is within the limit of 0.5% to 5% per application based on the weight of the uncoated fabric.