CA2245274A1 - Functional epoxy-silicone coatings for paper machine clothings and a method of coating same - Google Patents
Functional epoxy-silicone coatings for paper machine clothings and a method of coating same Download PDFInfo
- Publication number
- CA2245274A1 CA2245274A1 CA002245274A CA2245274A CA2245274A1 CA 2245274 A1 CA2245274 A1 CA 2245274A1 CA 002245274 A CA002245274 A CA 002245274A CA 2245274 A CA2245274 A CA 2245274A CA 2245274 A1 CA2245274 A1 CA 2245274A1
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- Prior art keywords
- coating
- fabric
- clothing
- set forth
- mass
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 52
- 239000011248 coating agent Substances 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims description 16
- 239000004447 silicone coating Substances 0.000 title 1
- 239000004744 fabric Substances 0.000 claims abstract description 89
- 238000011109 contamination Methods 0.000 claims abstract description 18
- 239000010410 layer Substances 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 239000003822 epoxy resin Substances 0.000 claims description 7
- 229920000647 polyepoxide Polymers 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 3
- 239000002356 single layer Substances 0.000 claims description 3
- 238000009740 moulding (composite fabrication) Methods 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims 2
- 229910052710 silicon Inorganic materials 0.000 claims 2
- 239000010703 silicon Substances 0.000 claims 2
- 238000009877 rendering Methods 0.000 claims 1
- 238000005507 spraying Methods 0.000 claims 1
- 230000035699 permeability Effects 0.000 abstract description 13
- 239000004593 Epoxy Substances 0.000 abstract description 2
- 239000007787 solid Substances 0.000 description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- 239000000356 contaminant Substances 0.000 description 6
- 239000008199 coating composition Substances 0.000 description 5
- 238000009472 formulation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229920006334 epoxy coating Polymers 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 229920000728 polyester Polymers 0.000 description 2
- 229920001296 polysiloxane Polymers 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 101001110310 Lentilactobacillus kefiri NADP-dependent (R)-specific alcohol dehydrogenase Proteins 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 229920001131 Pulp (paper) Polymers 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000000976 ink Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011269 tar Substances 0.000 description 1
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 238000009941 weaving Methods 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
- D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
- D06N3/128—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with silicon polymers
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/0027—Screen-cloths
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/30—Protecting wire-cloths from mechanical damage
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Paper (AREA)
- Laminated Bodies (AREA)
Abstract
The present invention is directed to fabrics for paper making machines that are rendered contamination resistant and maintain good permeability as a result of a durable coating that lasts the entire life of the fabric. A silicone-epoxy will render the fabric contamination resistant over the entire fabric lifetime.
Description
CA 0224~274 l998-08-lO
~UNC~lONA~ EPOXY-8ILICONE COATINGS FOR PAPER
M~G~TN~ CLOTHING8 AND A METHOD OF CO~TING SAME
FIELD OF THE lNV~ lON
The present invention is directed to fabrics for paper making machines that are rendered contamination resistant by a durable coating that lasts the entire life of the fabric, while not overly limiting the permeability of the fabric.
BACRGROUND OF THE lNV~ lON
The modern papermaker employs a highly sophisticated papermaking machine which is in essence a device for removing water from the paper furnish.
The water is removed sequentially in three stages or sections of the machine. In the first or forming section, the furnish is deposited on a moving forming fabric and water drained through the fabric to leave a paper sheet or web having a solids content of about 18 to 25 percent by weight. The formed web is carried into a press fabric section and passed through one or more nip presses on a moving press fabric to remove sufficient water to form a sheet having a solids content of about 36 to 50 percent by weight. This sheet is then transferred to the dryer section of the papermaking machine where dryer fabrics hold the paper sheet against hot, steam-heated dryer cylinders to obtain about 92 to 96 percent solids content. The papermaking fabrics employed on the papermaking machine must perform a diverse range of functions, according to the position on the machine, i.e., forming, press or dryer section.
Forming fabrics used in the papermaking process are a kind of papermaking fabric which are used in the forming section of a papermaking machine.
Forming fabrics are generally constructed of CA 0224~274 l998-08-lO
synthetic yarns joined together, ordinarily by weaving, in a fabric construction that is characterized by a high degree of open spaces between the intersecting yarns. Forming fabrics must maintain a high degree of openness to insure that they permit removal of water from the fiber slurry deposited thereon.
Since water removal capability is a critical function of the forming fabric, it is necessary to insure that the fabric retains a high degree of openness over its lifetime.
- However, the degree of openness of a fabric is continually reduced during its life. In addition to the fiber slurry, paper pulp ordinarily contains additives such as filler clay, pitch, and polymeric materials that clog the open spaces of the fabric.
The use of recycled fibers has introduced considerable amounts of contaminants in the form of inks, adhesives, tars, and polymeric materials, which 20 also clog the open spaces of the fabric. In addition, forming fabric designs now include multilayer fabrics that are more susceptible to contamination problems.
Accordingly, it is desirable to provide a fabric which exhibits an improved degree of contamination 25 resistance. one proposed prior art solution is the use of contamination resistant yarns in the construction of the fabric. This has not proved to be wholly satisfactory since the contamination resistance provided by such yarns is short-lived 30 and/or ineffective. Another proposed solution calls for coating or treating paper making fabrics in order to improve resistance to contaminants. Again, this method is not wholly successful because the contamination resistance provided by the coating is 35 short-lived and/or ineffective.
CA 0224~274 1998-08-10 U.S. Patent nos. 5,207,873 and 5,395,868 describe papermaking fabrics claimed to have permanent resistance to adhesion of contaminants.
The fabrics are coated with solutions having as their 5 primary components tetrafluoroethylene, urethane copolymer and polyacrylamide. This coating has not proven to be totally effective and/or permanent on paper machine clothing.
One problem generally inherent to coatings or treatments is that coatings per se are known to reduce the permeability of a fabric, an undesired result that inhibits water removal capabilities, the primary function of a forming fabric. It is therefore important that any coating applied to a 15 forming fabric reduce permeability as little as possible.
S~MMARY OF THE lNv~h~lON
An object of the present invention is to provide a fabric used in the forming, pressing, or drying 20 section of a paper making machine that exhibits an improved resistance to contamination over the entire life of the fabric. These fabrics are referred to as papermachine clothings by those skilled in the art, and the terms are generally interchangeable.
It is a further object of the invention to provide a durable coating that lasts the entire life of the fabric.
It is a further object of the invention to provide a coating which does not significantly affect 30 the permeability of the fabric.
It is a further object of the present invention to provide a coating for a fabric used in a papermaking machine that achieves the aforementioned objectives.
CA 0224~274 l998-08-lO
The present invention is a coated fabric used in a papermaking machine that has significantly enhanced resistance to contamination which lasts over the entire fabric lifetime. In another aspect, the invention is a method of coating a fabric used in a papermaking machine in order to enhance its resistance to contamination. The coating formulations disclosed herein have been shown to substantially improve the contamination resistance of a fabric while not significantly reducing the permeability of the fabric, and not increasing the mass of the fabric to any significant degree. That is, the present invention provides a thin, low weight coating for a papermachine clothings that adds limited mass to the fabric.
The applicants have found that a coating comprised of a silicon-epoxy resin will render a paper machine clothing contamination resistant over the entire fabric lifetime. Suitable silicon-epoxy coatings include aqueous mixtures that contain silicone epoxy resins. It is believed that the silicone-epoxy resins bond with the polyester or nylon filaments that form the clothing. A suitable line of silicone-epoxy resin compositions are available from Decora Industries, Fort Edward, New York under the trade name Wearlon~. A preferred formulation is Wearlon~ 2020-98, a three component formulation of a resin containing a silicone-epoxy based emulsion, a curing agent and a crosslinking agent. The components are mixed in-situ in accordance with the manufacturer's recommendations and applied to the fabrics and can be further diluted as necessary.
Effective contamination resistant fabrics have been prepared where the fabric coating formulation CA 0224~274 1998-08-10 contains 5% to about 50~ solids on a weight-weight basis, with a mass add-on of 0.1 % to 10.0 % based on the weight of the uncoated fabric. The % mass add on is:
5 100 X (basis ~eiqht of a drY. coated fabric - basis ~eiqht of a drY uncoated fabric) ( basis ~eight of a dry uncoated fabric As a general matter, a greater degree of the original permeability of a coated fabric is retained when the solids content of the coating or mass add on of the coating is reduced. Water, a preferred diluent for aqueous based coatings, may be used to reduce solids content and consequently % mass add on.
It has been found that fabrics having coating 15 formulations of a solids content in the range of 10%
to 15 % (W/W) or a mass add on of 1% to 3% maintain a high degree of their original permeability. That is, on the order of about 90% - 99% of their original permeability, which is preferred. In other words, 20 permeability is reduced only about 1% - 10% as a result of the coating. The fabrics can be coated in any conventional manner, including immersion within a coating bath, blade or bar coating techniques, squeegee coating, transfer coating, spray application, kiss or applicator roll, slot applicator, and brush applicator. Application with a kiss roll has been effective. The coating can be applied in a single pass, or it may be applied in multiple passes. Subsequent processing requires removing excess material and then drying or curing the coating as directed by the manufacture of that particular material. These methods are well known by those skilled in the art.
CA 0224~274 1998-08-10 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l is a photograph of an uncoated section of a contaminated fabric at 5X magnification.
Fig. 2 is a computer generated image of figure 1 with the fabric removed in order to show the contaminants.
Fig. 3 is a photograph of the coated section of a contaminated fabric at 5X magnification.
Fig. 4 is a computer generated image of figure 3 with the fabric removed in order to show contaminants, if any.
DETAILED DESCRIPTION OF TRE ~K~r~:KRED EMBODIMENTS
The following examples illustrate the invention and its applicability.
EXAMP~E 1 A triple layer forming fabric constructed of polyester filaments was coated on part of, but not all of its surface with a an aqueous solution of WEARLON~ 2020-98 silicon-epoxy coating (49% solids w/w) available from Decora Industries, Inc. of Fort Edward, N.Y. The coating formulation was applied in a single layer with a Binks #7 spray gun available from Binks Mfg. Co. of Franklin Park, Illinois.
Excess liquid was removed with a vacuum. Mass add on was determined as 8.3% based on the weight of the uncoated fabric. Portions of the belt were not coated in order to serve as a control.
The fabric was installed on a pilot machine and run for 3 days. The machine was running pulp consisting of 100% old corrugated container (OCC).
The speed of the machine ranged from 460-670 m/min (1500-2200 ft/min). Needle showers were used at 13.8 bars (200 psi) with no cleaning chemicals. After the trial, the fabric was removed and analyzed. The CA 0224~274 1998-08-10 following figures relate to the appearance and condition of the fabric after removal.
A contamination analysis was done on the sections of the fabric. Figures 1 and 3 are photographs taken at 5X magnification of each section. The pictures were then scanned into the computer with a gray color scale. The image was converted to a bitmap file (* bmp file), and opened in Microsoft Paintbrush (see Figs. 2 and 4), and the contaminants were colored in blue. The gray fabric was removed from the image leaving only the blue portion. This image was then imported into an image analysis program which counted the blue pixels and found a % contaminated area. The results are listed below:
8AMPLE % CONT~MTN~TED
1 Uncoated 4.1 2 Coated o. 3 All of the areas of the fabric that were coated exhibited an increase in contamination resistance over the areas of the fabric which were not coated.
EX~MPLE 2 Silicone epoxy coating formulations of WEARLON~
2020-98 were applied to fabrics at solids content ranging from 5% to 25% (w/w). Three coats were applied to a triple layer fabric via kiss roll applicator. The compositions of the formulations are provided in Table 1.
Three separate samples of the coated fabrics were measured for air permeability and mass add on as a result of coating and the average was taken. At a coating formulation having 15% solids, mass add on of the coating, when dry, was determined to be 11.18 g/m2, or 2.7 % based on the weight of the uncoated fabric.
CA 0224~274 1998-08-10 The coatings were allowed to cure for a period of one week. Three samples were cut from each of the fabrics per given coating and subjected to high pressure showering for a period of 8 hrs (oscillating 5 needle showers) under the conditions set forth below.
Data is presented in Tables 2 and 3. Mass, as reported in Table 2, is the mass of a 2" diameter sample taken from the fabrics.
HIGH PRESSURE SHOWER ~ NGS:
Fabric Tension = 39 PLI 6. 83 kN/m Size of Fabric Tested = 107" X 91l 272 cm x 22.9 cm Fabric Speed on Machine = 1500 ft./min 457 m/min Water Pressure = 400 psig 27.6 bars Shower Arm = 150 strokes/min 20Nozzle were spaced 1" apart across the length of the shower arm for uniform coverage.
Because of the demanding environment existing in a high pressure shower test and its duration (in this case, 400 psig for 8 hours), the test is a good measure of coating durability.
Table 3 is based on the data of Table 2. Table 3 expresses the data of Table 2 in terms of the changes in air permeability and mass add-on between the uncoated fabrics and the coated fabrics exposed to high pressure showering. Since the air permeability and mass add on of the showered, coated fabrics never return to the original levels of uncoated fabrics, it is evident that the coatings remain after exposure to the high pressure showering.
CA 0224~274 1998-08-10 %Solids 25% 15% 10% 5%
Water(gal) 48.98 69.39 79.59 89.80 Part "A" (gal) 40.82 24.49 16.33 8.16 Part "X" (gal) 2.04 1.22 0.82 0.41 Part "B"(gal)8.16 4.90 3.27 1.63 Total 100.00 100.00 100.00 100.00 Belt % 801ids Before 8howered Showering 1 Week After Coating After Coating 0 Uncoated 544 544 10 Belt %~olids Before Showered Showering 1 Week After Coating After Coating 0 Uncoated 0. 840 0.840 7 5 0.847 0.844 15 5 10 0.850 0.846 3 15 0.863 0.856 1 25 0.876 0.854 CA 0224~274 1998-08-10 Perm (% Decrease) Belt % 801ids Before Showered 8howering 1 Week After Coating After Coating 0 Uncoated --- ---7 5 2.33% 2.82%
3.98% 3.37%
3 15 4.59% 4.35%
0 1 25 5.88% 3.49%
Mass (% increase) Belt %801ids Before Showered 8howering 1 Week After Coating After Coating 15 0 Uncoated --- ---7 5 0.75% 0.44%
1.15% 0.71%
3 15 2.70% 1.90%
1 25 4.20% 1.59%
~UNC~lONA~ EPOXY-8ILICONE COATINGS FOR PAPER
M~G~TN~ CLOTHING8 AND A METHOD OF CO~TING SAME
FIELD OF THE lNV~ lON
The present invention is directed to fabrics for paper making machines that are rendered contamination resistant by a durable coating that lasts the entire life of the fabric, while not overly limiting the permeability of the fabric.
BACRGROUND OF THE lNV~ lON
The modern papermaker employs a highly sophisticated papermaking machine which is in essence a device for removing water from the paper furnish.
The water is removed sequentially in three stages or sections of the machine. In the first or forming section, the furnish is deposited on a moving forming fabric and water drained through the fabric to leave a paper sheet or web having a solids content of about 18 to 25 percent by weight. The formed web is carried into a press fabric section and passed through one or more nip presses on a moving press fabric to remove sufficient water to form a sheet having a solids content of about 36 to 50 percent by weight. This sheet is then transferred to the dryer section of the papermaking machine where dryer fabrics hold the paper sheet against hot, steam-heated dryer cylinders to obtain about 92 to 96 percent solids content. The papermaking fabrics employed on the papermaking machine must perform a diverse range of functions, according to the position on the machine, i.e., forming, press or dryer section.
Forming fabrics used in the papermaking process are a kind of papermaking fabric which are used in the forming section of a papermaking machine.
Forming fabrics are generally constructed of CA 0224~274 l998-08-lO
synthetic yarns joined together, ordinarily by weaving, in a fabric construction that is characterized by a high degree of open spaces between the intersecting yarns. Forming fabrics must maintain a high degree of openness to insure that they permit removal of water from the fiber slurry deposited thereon.
Since water removal capability is a critical function of the forming fabric, it is necessary to insure that the fabric retains a high degree of openness over its lifetime.
- However, the degree of openness of a fabric is continually reduced during its life. In addition to the fiber slurry, paper pulp ordinarily contains additives such as filler clay, pitch, and polymeric materials that clog the open spaces of the fabric.
The use of recycled fibers has introduced considerable amounts of contaminants in the form of inks, adhesives, tars, and polymeric materials, which 20 also clog the open spaces of the fabric. In addition, forming fabric designs now include multilayer fabrics that are more susceptible to contamination problems.
Accordingly, it is desirable to provide a fabric which exhibits an improved degree of contamination 25 resistance. one proposed prior art solution is the use of contamination resistant yarns in the construction of the fabric. This has not proved to be wholly satisfactory since the contamination resistance provided by such yarns is short-lived 30 and/or ineffective. Another proposed solution calls for coating or treating paper making fabrics in order to improve resistance to contaminants. Again, this method is not wholly successful because the contamination resistance provided by the coating is 35 short-lived and/or ineffective.
CA 0224~274 1998-08-10 U.S. Patent nos. 5,207,873 and 5,395,868 describe papermaking fabrics claimed to have permanent resistance to adhesion of contaminants.
The fabrics are coated with solutions having as their 5 primary components tetrafluoroethylene, urethane copolymer and polyacrylamide. This coating has not proven to be totally effective and/or permanent on paper machine clothing.
One problem generally inherent to coatings or treatments is that coatings per se are known to reduce the permeability of a fabric, an undesired result that inhibits water removal capabilities, the primary function of a forming fabric. It is therefore important that any coating applied to a 15 forming fabric reduce permeability as little as possible.
S~MMARY OF THE lNv~h~lON
An object of the present invention is to provide a fabric used in the forming, pressing, or drying 20 section of a paper making machine that exhibits an improved resistance to contamination over the entire life of the fabric. These fabrics are referred to as papermachine clothings by those skilled in the art, and the terms are generally interchangeable.
It is a further object of the invention to provide a durable coating that lasts the entire life of the fabric.
It is a further object of the invention to provide a coating which does not significantly affect 30 the permeability of the fabric.
It is a further object of the present invention to provide a coating for a fabric used in a papermaking machine that achieves the aforementioned objectives.
CA 0224~274 l998-08-lO
The present invention is a coated fabric used in a papermaking machine that has significantly enhanced resistance to contamination which lasts over the entire fabric lifetime. In another aspect, the invention is a method of coating a fabric used in a papermaking machine in order to enhance its resistance to contamination. The coating formulations disclosed herein have been shown to substantially improve the contamination resistance of a fabric while not significantly reducing the permeability of the fabric, and not increasing the mass of the fabric to any significant degree. That is, the present invention provides a thin, low weight coating for a papermachine clothings that adds limited mass to the fabric.
The applicants have found that a coating comprised of a silicon-epoxy resin will render a paper machine clothing contamination resistant over the entire fabric lifetime. Suitable silicon-epoxy coatings include aqueous mixtures that contain silicone epoxy resins. It is believed that the silicone-epoxy resins bond with the polyester or nylon filaments that form the clothing. A suitable line of silicone-epoxy resin compositions are available from Decora Industries, Fort Edward, New York under the trade name Wearlon~. A preferred formulation is Wearlon~ 2020-98, a three component formulation of a resin containing a silicone-epoxy based emulsion, a curing agent and a crosslinking agent. The components are mixed in-situ in accordance with the manufacturer's recommendations and applied to the fabrics and can be further diluted as necessary.
Effective contamination resistant fabrics have been prepared where the fabric coating formulation CA 0224~274 1998-08-10 contains 5% to about 50~ solids on a weight-weight basis, with a mass add-on of 0.1 % to 10.0 % based on the weight of the uncoated fabric. The % mass add on is:
5 100 X (basis ~eiqht of a drY. coated fabric - basis ~eiqht of a drY uncoated fabric) ( basis ~eight of a dry uncoated fabric As a general matter, a greater degree of the original permeability of a coated fabric is retained when the solids content of the coating or mass add on of the coating is reduced. Water, a preferred diluent for aqueous based coatings, may be used to reduce solids content and consequently % mass add on.
It has been found that fabrics having coating 15 formulations of a solids content in the range of 10%
to 15 % (W/W) or a mass add on of 1% to 3% maintain a high degree of their original permeability. That is, on the order of about 90% - 99% of their original permeability, which is preferred. In other words, 20 permeability is reduced only about 1% - 10% as a result of the coating. The fabrics can be coated in any conventional manner, including immersion within a coating bath, blade or bar coating techniques, squeegee coating, transfer coating, spray application, kiss or applicator roll, slot applicator, and brush applicator. Application with a kiss roll has been effective. The coating can be applied in a single pass, or it may be applied in multiple passes. Subsequent processing requires removing excess material and then drying or curing the coating as directed by the manufacture of that particular material. These methods are well known by those skilled in the art.
CA 0224~274 1998-08-10 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. l is a photograph of an uncoated section of a contaminated fabric at 5X magnification.
Fig. 2 is a computer generated image of figure 1 with the fabric removed in order to show the contaminants.
Fig. 3 is a photograph of the coated section of a contaminated fabric at 5X magnification.
Fig. 4 is a computer generated image of figure 3 with the fabric removed in order to show contaminants, if any.
DETAILED DESCRIPTION OF TRE ~K~r~:KRED EMBODIMENTS
The following examples illustrate the invention and its applicability.
EXAMP~E 1 A triple layer forming fabric constructed of polyester filaments was coated on part of, but not all of its surface with a an aqueous solution of WEARLON~ 2020-98 silicon-epoxy coating (49% solids w/w) available from Decora Industries, Inc. of Fort Edward, N.Y. The coating formulation was applied in a single layer with a Binks #7 spray gun available from Binks Mfg. Co. of Franklin Park, Illinois.
Excess liquid was removed with a vacuum. Mass add on was determined as 8.3% based on the weight of the uncoated fabric. Portions of the belt were not coated in order to serve as a control.
The fabric was installed on a pilot machine and run for 3 days. The machine was running pulp consisting of 100% old corrugated container (OCC).
The speed of the machine ranged from 460-670 m/min (1500-2200 ft/min). Needle showers were used at 13.8 bars (200 psi) with no cleaning chemicals. After the trial, the fabric was removed and analyzed. The CA 0224~274 1998-08-10 following figures relate to the appearance and condition of the fabric after removal.
A contamination analysis was done on the sections of the fabric. Figures 1 and 3 are photographs taken at 5X magnification of each section. The pictures were then scanned into the computer with a gray color scale. The image was converted to a bitmap file (* bmp file), and opened in Microsoft Paintbrush (see Figs. 2 and 4), and the contaminants were colored in blue. The gray fabric was removed from the image leaving only the blue portion. This image was then imported into an image analysis program which counted the blue pixels and found a % contaminated area. The results are listed below:
8AMPLE % CONT~MTN~TED
1 Uncoated 4.1 2 Coated o. 3 All of the areas of the fabric that were coated exhibited an increase in contamination resistance over the areas of the fabric which were not coated.
EX~MPLE 2 Silicone epoxy coating formulations of WEARLON~
2020-98 were applied to fabrics at solids content ranging from 5% to 25% (w/w). Three coats were applied to a triple layer fabric via kiss roll applicator. The compositions of the formulations are provided in Table 1.
Three separate samples of the coated fabrics were measured for air permeability and mass add on as a result of coating and the average was taken. At a coating formulation having 15% solids, mass add on of the coating, when dry, was determined to be 11.18 g/m2, or 2.7 % based on the weight of the uncoated fabric.
CA 0224~274 1998-08-10 The coatings were allowed to cure for a period of one week. Three samples were cut from each of the fabrics per given coating and subjected to high pressure showering for a period of 8 hrs (oscillating 5 needle showers) under the conditions set forth below.
Data is presented in Tables 2 and 3. Mass, as reported in Table 2, is the mass of a 2" diameter sample taken from the fabrics.
HIGH PRESSURE SHOWER ~ NGS:
Fabric Tension = 39 PLI 6. 83 kN/m Size of Fabric Tested = 107" X 91l 272 cm x 22.9 cm Fabric Speed on Machine = 1500 ft./min 457 m/min Water Pressure = 400 psig 27.6 bars Shower Arm = 150 strokes/min 20Nozzle were spaced 1" apart across the length of the shower arm for uniform coverage.
Because of the demanding environment existing in a high pressure shower test and its duration (in this case, 400 psig for 8 hours), the test is a good measure of coating durability.
Table 3 is based on the data of Table 2. Table 3 expresses the data of Table 2 in terms of the changes in air permeability and mass add-on between the uncoated fabrics and the coated fabrics exposed to high pressure showering. Since the air permeability and mass add on of the showered, coated fabrics never return to the original levels of uncoated fabrics, it is evident that the coatings remain after exposure to the high pressure showering.
CA 0224~274 1998-08-10 %Solids 25% 15% 10% 5%
Water(gal) 48.98 69.39 79.59 89.80 Part "A" (gal) 40.82 24.49 16.33 8.16 Part "X" (gal) 2.04 1.22 0.82 0.41 Part "B"(gal)8.16 4.90 3.27 1.63 Total 100.00 100.00 100.00 100.00 Belt % 801ids Before 8howered Showering 1 Week After Coating After Coating 0 Uncoated 544 544 10 Belt %~olids Before Showered Showering 1 Week After Coating After Coating 0 Uncoated 0. 840 0.840 7 5 0.847 0.844 15 5 10 0.850 0.846 3 15 0.863 0.856 1 25 0.876 0.854 CA 0224~274 1998-08-10 Perm (% Decrease) Belt % 801ids Before Showered 8howering 1 Week After Coating After Coating 0 Uncoated --- ---7 5 2.33% 2.82%
3.98% 3.37%
3 15 4.59% 4.35%
0 1 25 5.88% 3.49%
Mass (% increase) Belt %801ids Before Showered 8howering 1 Week After Coating After Coating 15 0 Uncoated --- ---7 5 0.75% 0.44%
1.15% 0.71%
3 15 2.70% 1.90%
1 25 4.20% 1.59%
Claims (17)
1. A contamination resistant papermachine clothing for use in the forming, pressing or drying section of a papermaking machine comprised of a fabric coated with at least one layer of a coating containing a silicon epoxy resin.
2. The paper machine clothing of claim 1 wherein the coating is a silicon-epoxy resin applied from an aqueous mixture.
3. The papermachine clothing as set forth in claim 1 wherein the mass add-on of the coating when dry is 0.1% to 10.0 % based on the mass of the clothing.
4. The papermachine clothing as set forth in claim 1 wherein the mass add-on of the coating when dry is 1.0 % to 3.0 % based on the mass of the clothing.
5. The papermachine clothing of claim 1 wherein the coating is applied in at least two layers.
6. The papermachine clothing as set forth in claim 1 wherein the coating applied to the clothing is cured.
7. The papermachine clothing as set forth in claim 1 wherein the clothing is a single layer fabric.
8. The papermachine clothing as set forth in claim 1 wherein the clothing is a multi layer fabric.
9. A method of rendering a papermachine clothing contamination resistant comprised of the steps of applying at least one layer of a silicon epoxy resin to a paper machine clothing.
10. The method as set forth in claim 9 wherein the coating is applied by spraying.
11. The method as set forth in claim 9 wherein the coating is applied by kiss roll applicator.
12. The method as set forth in claim 9 wherein the coating is applied in at least two layers.
13. The method as set forth in claim 9 wherein the coating applied to the clothing is cured.
14. The method as set forth in claim 9 wherein the fabric is a single-layer fabric.
15. The method as set forth in claim 9 wherein the fabric is a multi-layer fabric.
16. The method as set forth in claim 9 wherein the mass add-on of the coating, when dry, is 0.1% to 10.0 % based on the mass of the clothing.
17. The method as set forth in claim 9 wherein the mass add-on of the coating, when dry, is 1.0 % to 3.0 % based on the mass of the clothing.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US90855697A | 1997-08-08 | 1997-08-08 | |
US08/908,556 | 1997-08-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2245274A1 true CA2245274A1 (en) | 1999-02-08 |
Family
ID=25425972
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002245274A Abandoned CA2245274A1 (en) | 1997-08-08 | 1998-08-10 | Functional epoxy-silicone coatings for paper machine clothings and a method of coating same |
Country Status (10)
Country | Link |
---|---|
EP (1) | EP0896086A3 (en) |
JP (1) | JPH11172593A (en) |
KR (1) | KR19990023136A (en) |
CN (1) | CN1210172A (en) |
AU (1) | AU6059098A (en) |
BR (1) | BR9802355A (en) |
CA (1) | CA2245274A1 (en) |
ID (1) | ID20663A (en) |
NO (1) | NO983619L (en) |
ZA (1) | ZA982563B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4522212B2 (en) * | 2004-09-29 | 2010-08-11 | イチカワ株式会社 | Paper transport felt and press machine of paper machine equipped with the paper transport felt |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57171790A (en) * | 1980-12-06 | 1982-10-22 | Nihon Felt Kk | Papermaking cloth having anti-stain property |
US5002801A (en) * | 1988-10-31 | 1991-03-26 | Albany International Corp. | Paper machine fabrics having controlled release |
US5207873A (en) * | 1992-04-17 | 1993-05-04 | Huyck Corporation | Anti-contaminant treatment for papermaking fabrics |
-
1998
- 1998-03-26 ZA ZA982563A patent/ZA982563B/en unknown
- 1998-04-01 AU AU60590/98A patent/AU6059098A/en not_active Abandoned
- 1998-05-20 KR KR1019980018099A patent/KR19990023136A/en not_active Application Discontinuation
- 1998-06-23 EP EP98202079A patent/EP0896086A3/en not_active Withdrawn
- 1998-07-08 BR BR9802355-1A patent/BR9802355A/en not_active Application Discontinuation
- 1998-08-06 NO NO983619A patent/NO983619L/en not_active Application Discontinuation
- 1998-08-06 ID IDP981096A patent/ID20663A/en unknown
- 1998-08-07 JP JP10236305A patent/JPH11172593A/en active Pending
- 1998-08-07 CN CN98116226A patent/CN1210172A/en active Pending
- 1998-08-10 CA CA002245274A patent/CA2245274A1/en not_active Abandoned
Also Published As
Publication number | Publication date |
---|---|
EP0896086A2 (en) | 1999-02-10 |
CN1210172A (en) | 1999-03-10 |
BR9802355A (en) | 1999-12-28 |
ID20663A (en) | 1999-02-11 |
JPH11172593A (en) | 1999-06-29 |
EP0896086A3 (en) | 1999-10-13 |
NO983619L (en) | 1999-02-09 |
NO983619D0 (en) | 1998-08-06 |
ZA982563B (en) | 1998-10-08 |
KR19990023136A (en) | 1999-03-25 |
AU6059098A (en) | 1999-03-11 |
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