CA2013852C - Paper machine pressing fabrics - Google Patents
Paper machine pressing fabrics Download PDFInfo
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- CA2013852C CA2013852C CA002013852A CA2013852A CA2013852C CA 2013852 C CA2013852 C CA 2013852C CA 002013852 A CA002013852 A CA 002013852A CA 2013852 A CA2013852 A CA 2013852A CA 2013852 C CA2013852 C CA 2013852C
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- Prior art keywords
- treated
- polyamide fibers
- phenol
- fabric
- aldehyde
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Classifications
-
- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M15/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment
- D06M15/19—Treating fibres, threads, yarns, fabrics, or fibrous goods made from such materials, with macromolecular compounds; Such treatment combined with mechanical treatment with synthetic macromolecular compounds
- D06M15/37—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D06M15/39—Aldehyde resins; Ketone resins; Polyacetals
- D06M15/41—Phenol-aldehyde or phenol-ketone resins
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
- D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
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- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Paper (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Polarising Elements (AREA)
- Artificial Filaments (AREA)
- Polyamides (AREA)
- Heat Sensitive Colour Forming Recording (AREA)
- Woven Fabrics (AREA)
- Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Nonwoven Fabrics (AREA)
- Reinforced Plastic Materials (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Filtering Materials (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
- Treatment Of Fiber Materials (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Printing Plates And Materials Therefor (AREA)
Abstract
The present invention relates to a polymeric material from the family of polyamides characterised in that said polyamides have an amine end group concentration of at least 60 equivalents/10 6g, and have been subjected to a phenol/aldehyde treatment process, to increase the intrinsic viscosity by at least 4%
compared with standard materials.
compared with standard materials.
Description
PAPER MACHINE PRESSING FABRICS
DESCRIPTION
This invention relates to paper machine pressing fabrics and has particular reference to paper machine pressing fabrics formed of a polyamide material and having improved longevity and resistance to flattening in the surface layer.
In paper making machines, a slurry of paper making constituents referred to as "furnish" is deposited on a forming fabric or "wire" and the liquid constituent furnish is drawn or extracted through the fabric or wire to produce a self-cohesive sheet. This self-cohesive sheet is then passed to a pressing and then a drying section of the paper making machine.
In the pressing section, the paper sheet is transported by a pressing fabric to a pair of rollers where the fabric and the paper sheet pass between the nip of the rollers to dewater by mechanical pressure the paper sheet.
The paper sheet itself may contain other types of .
chemical finishes and additives and could be, at the same time, subjected to an elevated temperature in order to aid the dewatering. The paper making pressing fabric together with its sheet of paper tends, therefore, to be subjected to immense pressure at elevated temperatures in a rigorous chemical environment. Paper making pressing fabrics are generally produced by needling batt fiber to a woven base fabric. The fabric has multiple functions: first, to support the formed paper sheet through the press section of the machine; secondly, to accept sheet water expressed at each press nip; and last, to impart a finish or surface texture to the paper sheet.
The batt fiber layer constitutes a "cushion" and support for the paper sheet while the woven base provides the primary channels or voids to accept expressed sheet water. The quality of the batt fiber layer and in particular its surface properties and its consistency of surface properties with time, is of extreme importance. As the surface properties of the batt fiber layer deteriorates, so does the quality of the surface of the paper sheet being pressed, as well as, the uniformity of water removal.
In the nip of the press rolls, the batt fibers are bent and deformed under great pressure and at great frequency. Hence the mechanical properties of the batt fiber are of considerable importance in such processes.
Polyamide 6 and polyamide 6,6 have been used extensively in the manufacture of paper machine pressing fabrics. These polymers are readily formable as fibers and their fiber characteristics can be controlled to make acceptable paper making pressing fabrics.
Treatment of polyamide (PA) fibers in general has been proposed, but none have been specifically concerned with the improvement of the mechanical performance of fibers as used in paper machine clothing. Among the f~i _ 4 _ 20 ~ 3a5Z
prior proposals for the treatment of polyamide fibers are the following:-United States Patent Specification No. 2,434,247 issued to Lewis et al. relates to the modification of synthetic linear polyamides with formaldehyde and an alcohol to obtain a more elastic nylon for woven fabrics .
United States Patent Specification No. 2,430,953 issued on November 18, 1947 to Schneider is concerned with producing nylon yarns with a softer hand, better drape, and in addition, a higher melting point, better dye receptivity and increased resistance to solvents. The polyamide yarns are reacted with formaldehyde at a pH below 3 in alcohol.
United States Patent Specification No. 2,425,334 issued on August 12, 1947 to McCreath relates to modification of polyamides with formaldehyde at a pH
less than 3 so that they can be cold drawn by no more than 75~ of their original lengths.
United States Patent Specification No. 3,276,839 issued on October 4, 1966 to Fruh describes a process for finishing and dyeing synthetic nylon textile materials in the presence of phenol and an aliphatic anion-active compound in alkaline medium.
- 5 _ 2013852 United States Patent Specification No. 3,322,488 issued on May 30, 1967 to Feeman refers to sulfomethylated bisphenol-formaldehyde condensation products used as dye resists for synthetic polyamide f fibers .
United States Patent Specification No. 2,533,100 issued to Flugel et al. relates to a process for treating synthetic linear polyamides with thio derivatives of phenols or their corresponding reduction products.
United States Patent Specification No. 2,388,676 issued to Coffman et al. is concerned with improving the light stability of polyamide fibers by forming a catecholaldehyde resin within the nylon.
In each of the above cases the nylon materials exhibit improved properties for use in apparrel or decorative assembly, i.e. use in conditions that will not be subjected to the aggressive physical and chemical environment of a paper making machine.
As paper machine technology improves, speeds, operating temperatures and pressures increase with a result that the tendency of existing pressing fabrics to compact and wear is increased.
Furthermore, increased degradation with increasing temperature of operation and increasing speed of the ~.
machine results in significantly shorter service life for these fabrics.
The present applicant has discovered that a paper making pressing fabric using fibers of various polyamides having an increased amine end group concentration can be fiu~ther processed and modified to produce signifi-cantly improved properties.
Therefore, in accordance with the present invention, there is provided a treated polyamide fiber comprising treated polyamide fibers having an 1o initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and for a time sui~cient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to untreated polyamide fibers.
2 o Also in accordance with the present invention, there is provided a treated paper machine pressing fabric comprising treated polyamide fibers having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment 2 5 which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time su~cient to increase the - 6a - 2013852 intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
Further in accordance with the present invention, there is provided a treated paper machine pressing fabric comprising treated polyamide fibers, filaments and/or yarns having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy and groups greater than 1.0, the polyamide fibers, filaments and/or yarns being treated with a phenol/aldehyde treatment 1 o which comprises contacting the polyamide fibers, filaments and/or yarns with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time sufficient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
a U
- 6b -According to the present invention there is provided a paper making pressing fabric comprising a fiber layer formed of various polyamides characterised in that said polyamide has an amine end group concentration such that the amine end group/carboxy end group ratio is greater than 1 which has been subjected to a phenol/aldehyde treatment process to increase the intrinsic viscosity of by at least 4~
compared with the untreated material.
r.. 20~ 3a5Z
In one embodiment of the invention, the amine end group concentration is at least 60 equivalents/106g.
Where the polyamide is polyamide 6,6, the intrinsic viscosity after treatment process is preferably not less than 1.3 dl/g; said fiber layer can just be the surface layer or layers of the batt structure and/or any portion of the batt up to 100 of the batt structure.
In another aspect of the present invention there is provided a method of making a paper making pressing fabric which method comprises treating a polyamide fiber having an amine end group concentration of at least 60 equivalent/106 gram with an aldehyde/phenol treatment process by contacting the fiber with an aqueous solution of an aldehyde at an elevated temperature and with an aqueous solution of a phenol at an elevated temperature, the treatment process being carried out at a temperature for a time sufficient to impart an increase in intrinsic viscosity of the polyamide by at least 4~ and thereafter forming a layer of said fibers and needling onto a woven base fabric. The fiber may be formed into 1~~~~
_8_ a batt layer prior to attaching to the base fabric either before or after the aldehyde/phenol treatment procedure.
Since the woven base fabrics contain yarns of monofilament, multifilament, or spun from staple fibers, that are usually polyamide based, the technology of the present invention can be utilized for these yarn forms since they are also exposed to the heat, pressure and chemical environment already described. Benefits of dimensional stability, strength retention and maintenance of water handling capacity are all vital, and will be improved using yarns prepared by this invention.
Also, while usual manufacturing techniques apply a batt formed of fiber onto a woven base fabric, this should not limit the scope of this invention. Other methods to apply fiber, to anchor the fiber instead of mechanically needling, whether the base is woven or not, or whether there is even a support base should all be considered in producing a pressing fabric.
_ 9 _ The word "fiber" should also not be limited in the sense of size dimensions or shape, but be considered a component. In this sense, therefore, for the purposes of this specification, the use of the term "fiber" should also include "yarns".
Phenols which can be used in this process include phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol and phloroglucinol, as well as, substituted products of the aforementioned compounds provided at least two reactive sites are left open on the aromatic ring. In addition, bisphenols, dihydroxy-naphthalenes and the like could also be utilized.
Aldehydes applicable to this process are formaldehyde, formaldehyde liberating compounds, oxaldehyde, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde, suberaldehyde, azelaldehyde and sebacaldehyde, and the like, as well as their substituted counterparts.
The treated polyamide batt fibers show an increase in intrinsic viscosity up to 25~ depending on the phenolic compound and subsequent heat treatment -lo-employed. These fibers also exhibit higher wet elongations relative to standard polyamide fibers both before, but especially after the treatment process.
There is also a significant improvement in chemical resistance particularly in terms of resistance to degradation of physical properties caused by oxidation by chlorine containing compounds during use on a paper making machine. Fibers also show increased resistance to abrasion resulting from the pressing of papers containing fillers, such as ground calcium carbonate.
Such pressing fabrics have exhibited as much as 100$
longer lifetime in use, particularly in hostile chemical and mechanically abrasive environments.
Following is a description by way of example only of methods of carrying the invention into effect.
L~YTMDT L~ 1 Polyamide 6,6 15d staple fiber having an amine end group concentration of 66.4 equivalent/106 gram and an intrinsic viscosity of 1.35 dl/g was subjected to a phenolic treatment process as described below.
The fiber was first immersed in an aqueous bath consisting of 0.5$ ethylene diamine and 2.0~
formaldehyde at 130°F for 30 minutes. After a rinse, the fiber is then subjected to a second aqueous solution~of 1.5$ resorcinol and 1~ formaldehyde at 130°F for one hour. Followed by a rinse cycle, the sample was subsequently air dried and heated 10 minutes at 300°F.
,-The Table 1 below compares intrinsic viscosities and tensile properties of fiber processed with the above formulation and untreated PA 6,6 fibers having high and low amine end groups. Table 2 includes data describing the properties after exposure to sodium hypochlorite solution in a standard degradation test.
A 6$ increase in intrinsic viscosity is observed for the high amine end group fibers after treatment. In addition, these fibers have higher elongations compared to the Control. This higher elongation contributes to the higher Tensile Energy Absorption or "toughness" values. This parameter is important in considering end-use requirements such as resiliency which is an important factor on a paper machine. The treated high amine end group fibers maintain high elongation and tensile energy absorption relative to the control even after exposure to hypochlorite.
Additional PA 6,6 fiber samples having low and high amine concentration were treated as described in Example 1 above (designated as "X" treatment) using 1/10 and 1/2 the chemical concentrations. The samples were then subjected to a simulated papermaking test in which they were exposed to repeated compression for a given number cycles and were reviewed and judged on a relative ranking on a scale of 0 to 5.
Examination of Table 3 below shows that the treated high amine end group fibers give superior properties in terms of improved ranking on the simulated papermaking press. According to the table, the lower the ranking the better the results.
One field trial was run on the third press position of a paper machine which produces uncoated printing and writing grades of paper, mainly bond and copy papers.
The particular machine has been identified to have extremely high chlorine residuals in their stock water and shower water (in excess of 2.0 ppm).
The standard fabrics have been chemically treated with the best known art to offer a degree of protection to the polyamide fiber in the batt structure. Even so, effective fabric life is less than three weeks, with substantial wear and compaction causing loss of efficient water removal. In extreme cases, fabrics actually tore off the machine due to the degraded state.
At the time of the trial, the previous three fabrics had run 12 days each, one tearing off. The trial fabric structure utilized was composed of 100 of the modified polyamide fiber, with the addition of the special process steps of the invention. Our trial ran 12 days and was scheduled off. The fabric showed no signs of instability and our analysis of the used fabric revealed low weight loss, no fiber fibrillation and fatigue, and little loss to bulk and water handling capacity.
201385?
Subsequent fabrics exposed to the invention's process have run as long as 39 days on this position with the fabrics still in a usable physical condition at time of removal. Competitive fabrics have run no longer than 14 days during this time period.
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Table 3 Papermakina Press Ranking (Scale 0-5) Fibers Treatment 700,000 Cycles High amine end group Control-- 3.5 High amine end group 1/10 X 2,2 High amine end group 1/2 X 1,g High amine end group X
Low amine end group Control-- 3-7 Low amine end group 1/10 X 3.8 Low amine end group X 3-3
DESCRIPTION
This invention relates to paper machine pressing fabrics and has particular reference to paper machine pressing fabrics formed of a polyamide material and having improved longevity and resistance to flattening in the surface layer.
In paper making machines, a slurry of paper making constituents referred to as "furnish" is deposited on a forming fabric or "wire" and the liquid constituent furnish is drawn or extracted through the fabric or wire to produce a self-cohesive sheet. This self-cohesive sheet is then passed to a pressing and then a drying section of the paper making machine.
In the pressing section, the paper sheet is transported by a pressing fabric to a pair of rollers where the fabric and the paper sheet pass between the nip of the rollers to dewater by mechanical pressure the paper sheet.
The paper sheet itself may contain other types of .
chemical finishes and additives and could be, at the same time, subjected to an elevated temperature in order to aid the dewatering. The paper making pressing fabric together with its sheet of paper tends, therefore, to be subjected to immense pressure at elevated temperatures in a rigorous chemical environment. Paper making pressing fabrics are generally produced by needling batt fiber to a woven base fabric. The fabric has multiple functions: first, to support the formed paper sheet through the press section of the machine; secondly, to accept sheet water expressed at each press nip; and last, to impart a finish or surface texture to the paper sheet.
The batt fiber layer constitutes a "cushion" and support for the paper sheet while the woven base provides the primary channels or voids to accept expressed sheet water. The quality of the batt fiber layer and in particular its surface properties and its consistency of surface properties with time, is of extreme importance. As the surface properties of the batt fiber layer deteriorates, so does the quality of the surface of the paper sheet being pressed, as well as, the uniformity of water removal.
In the nip of the press rolls, the batt fibers are bent and deformed under great pressure and at great frequency. Hence the mechanical properties of the batt fiber are of considerable importance in such processes.
Polyamide 6 and polyamide 6,6 have been used extensively in the manufacture of paper machine pressing fabrics. These polymers are readily formable as fibers and their fiber characteristics can be controlled to make acceptable paper making pressing fabrics.
Treatment of polyamide (PA) fibers in general has been proposed, but none have been specifically concerned with the improvement of the mechanical performance of fibers as used in paper machine clothing. Among the f~i _ 4 _ 20 ~ 3a5Z
prior proposals for the treatment of polyamide fibers are the following:-United States Patent Specification No. 2,434,247 issued to Lewis et al. relates to the modification of synthetic linear polyamides with formaldehyde and an alcohol to obtain a more elastic nylon for woven fabrics .
United States Patent Specification No. 2,430,953 issued on November 18, 1947 to Schneider is concerned with producing nylon yarns with a softer hand, better drape, and in addition, a higher melting point, better dye receptivity and increased resistance to solvents. The polyamide yarns are reacted with formaldehyde at a pH below 3 in alcohol.
United States Patent Specification No. 2,425,334 issued on August 12, 1947 to McCreath relates to modification of polyamides with formaldehyde at a pH
less than 3 so that they can be cold drawn by no more than 75~ of their original lengths.
United States Patent Specification No. 3,276,839 issued on October 4, 1966 to Fruh describes a process for finishing and dyeing synthetic nylon textile materials in the presence of phenol and an aliphatic anion-active compound in alkaline medium.
- 5 _ 2013852 United States Patent Specification No. 3,322,488 issued on May 30, 1967 to Feeman refers to sulfomethylated bisphenol-formaldehyde condensation products used as dye resists for synthetic polyamide f fibers .
United States Patent Specification No. 2,533,100 issued to Flugel et al. relates to a process for treating synthetic linear polyamides with thio derivatives of phenols or their corresponding reduction products.
United States Patent Specification No. 2,388,676 issued to Coffman et al. is concerned with improving the light stability of polyamide fibers by forming a catecholaldehyde resin within the nylon.
In each of the above cases the nylon materials exhibit improved properties for use in apparrel or decorative assembly, i.e. use in conditions that will not be subjected to the aggressive physical and chemical environment of a paper making machine.
As paper machine technology improves, speeds, operating temperatures and pressures increase with a result that the tendency of existing pressing fabrics to compact and wear is increased.
Furthermore, increased degradation with increasing temperature of operation and increasing speed of the ~.
machine results in significantly shorter service life for these fabrics.
The present applicant has discovered that a paper making pressing fabric using fibers of various polyamides having an increased amine end group concentration can be fiu~ther processed and modified to produce signifi-cantly improved properties.
Therefore, in accordance with the present invention, there is provided a treated polyamide fiber comprising treated polyamide fibers having an 1o initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and for a time sui~cient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to untreated polyamide fibers.
2 o Also in accordance with the present invention, there is provided a treated paper machine pressing fabric comprising treated polyamide fibers having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment 2 5 which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time su~cient to increase the - 6a - 2013852 intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
Further in accordance with the present invention, there is provided a treated paper machine pressing fabric comprising treated polyamide fibers, filaments and/or yarns having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy and groups greater than 1.0, the polyamide fibers, filaments and/or yarns being treated with a phenol/aldehyde treatment 1 o which comprises contacting the polyamide fibers, filaments and/or yarns with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time sufficient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
a U
- 6b -According to the present invention there is provided a paper making pressing fabric comprising a fiber layer formed of various polyamides characterised in that said polyamide has an amine end group concentration such that the amine end group/carboxy end group ratio is greater than 1 which has been subjected to a phenol/aldehyde treatment process to increase the intrinsic viscosity of by at least 4~
compared with the untreated material.
r.. 20~ 3a5Z
In one embodiment of the invention, the amine end group concentration is at least 60 equivalents/106g.
Where the polyamide is polyamide 6,6, the intrinsic viscosity after treatment process is preferably not less than 1.3 dl/g; said fiber layer can just be the surface layer or layers of the batt structure and/or any portion of the batt up to 100 of the batt structure.
In another aspect of the present invention there is provided a method of making a paper making pressing fabric which method comprises treating a polyamide fiber having an amine end group concentration of at least 60 equivalent/106 gram with an aldehyde/phenol treatment process by contacting the fiber with an aqueous solution of an aldehyde at an elevated temperature and with an aqueous solution of a phenol at an elevated temperature, the treatment process being carried out at a temperature for a time sufficient to impart an increase in intrinsic viscosity of the polyamide by at least 4~ and thereafter forming a layer of said fibers and needling onto a woven base fabric. The fiber may be formed into 1~~~~
_8_ a batt layer prior to attaching to the base fabric either before or after the aldehyde/phenol treatment procedure.
Since the woven base fabrics contain yarns of monofilament, multifilament, or spun from staple fibers, that are usually polyamide based, the technology of the present invention can be utilized for these yarn forms since they are also exposed to the heat, pressure and chemical environment already described. Benefits of dimensional stability, strength retention and maintenance of water handling capacity are all vital, and will be improved using yarns prepared by this invention.
Also, while usual manufacturing techniques apply a batt formed of fiber onto a woven base fabric, this should not limit the scope of this invention. Other methods to apply fiber, to anchor the fiber instead of mechanically needling, whether the base is woven or not, or whether there is even a support base should all be considered in producing a pressing fabric.
_ 9 _ The word "fiber" should also not be limited in the sense of size dimensions or shape, but be considered a component. In this sense, therefore, for the purposes of this specification, the use of the term "fiber" should also include "yarns".
Phenols which can be used in this process include phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol and phloroglucinol, as well as, substituted products of the aforementioned compounds provided at least two reactive sites are left open on the aromatic ring. In addition, bisphenols, dihydroxy-naphthalenes and the like could also be utilized.
Aldehydes applicable to this process are formaldehyde, formaldehyde liberating compounds, oxaldehyde, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde, suberaldehyde, azelaldehyde and sebacaldehyde, and the like, as well as their substituted counterparts.
The treated polyamide batt fibers show an increase in intrinsic viscosity up to 25~ depending on the phenolic compound and subsequent heat treatment -lo-employed. These fibers also exhibit higher wet elongations relative to standard polyamide fibers both before, but especially after the treatment process.
There is also a significant improvement in chemical resistance particularly in terms of resistance to degradation of physical properties caused by oxidation by chlorine containing compounds during use on a paper making machine. Fibers also show increased resistance to abrasion resulting from the pressing of papers containing fillers, such as ground calcium carbonate.
Such pressing fabrics have exhibited as much as 100$
longer lifetime in use, particularly in hostile chemical and mechanically abrasive environments.
Following is a description by way of example only of methods of carrying the invention into effect.
L~YTMDT L~ 1 Polyamide 6,6 15d staple fiber having an amine end group concentration of 66.4 equivalent/106 gram and an intrinsic viscosity of 1.35 dl/g was subjected to a phenolic treatment process as described below.
The fiber was first immersed in an aqueous bath consisting of 0.5$ ethylene diamine and 2.0~
formaldehyde at 130°F for 30 minutes. After a rinse, the fiber is then subjected to a second aqueous solution~of 1.5$ resorcinol and 1~ formaldehyde at 130°F for one hour. Followed by a rinse cycle, the sample was subsequently air dried and heated 10 minutes at 300°F.
,-The Table 1 below compares intrinsic viscosities and tensile properties of fiber processed with the above formulation and untreated PA 6,6 fibers having high and low amine end groups. Table 2 includes data describing the properties after exposure to sodium hypochlorite solution in a standard degradation test.
A 6$ increase in intrinsic viscosity is observed for the high amine end group fibers after treatment. In addition, these fibers have higher elongations compared to the Control. This higher elongation contributes to the higher Tensile Energy Absorption or "toughness" values. This parameter is important in considering end-use requirements such as resiliency which is an important factor on a paper machine. The treated high amine end group fibers maintain high elongation and tensile energy absorption relative to the control even after exposure to hypochlorite.
Additional PA 6,6 fiber samples having low and high amine concentration were treated as described in Example 1 above (designated as "X" treatment) using 1/10 and 1/2 the chemical concentrations. The samples were then subjected to a simulated papermaking test in which they were exposed to repeated compression for a given number cycles and were reviewed and judged on a relative ranking on a scale of 0 to 5.
Examination of Table 3 below shows that the treated high amine end group fibers give superior properties in terms of improved ranking on the simulated papermaking press. According to the table, the lower the ranking the better the results.
One field trial was run on the third press position of a paper machine which produces uncoated printing and writing grades of paper, mainly bond and copy papers.
The particular machine has been identified to have extremely high chlorine residuals in their stock water and shower water (in excess of 2.0 ppm).
The standard fabrics have been chemically treated with the best known art to offer a degree of protection to the polyamide fiber in the batt structure. Even so, effective fabric life is less than three weeks, with substantial wear and compaction causing loss of efficient water removal. In extreme cases, fabrics actually tore off the machine due to the degraded state.
At the time of the trial, the previous three fabrics had run 12 days each, one tearing off. The trial fabric structure utilized was composed of 100 of the modified polyamide fiber, with the addition of the special process steps of the invention. Our trial ran 12 days and was scheduled off. The fabric showed no signs of instability and our analysis of the used fabric revealed low weight loss, no fiber fibrillation and fatigue, and little loss to bulk and water handling capacity.
201385?
Subsequent fabrics exposed to the invention's process have run as long as 39 days on this position with the fabrics still in a usable physical condition at time of removal. Competitive fabrics have run no longer than 14 days during this time period.
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Table 3 Papermakina Press Ranking (Scale 0-5) Fibers Treatment 700,000 Cycles High amine end group Control-- 3.5 High amine end group 1/10 X 2,2 High amine end group 1/2 X 1,g High amine end group X
Low amine end group Control-- 3-7 Low amine end group 1/10 X 3.8 Low amine end group X 3-3
Claims (20)
1. A treated polyamide fiber comprising treated polyamide fibers having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and for a time sufficient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to untreated polyamide fibers.
2. The treated polyamide fiber as claimed in Claim 1 wherein said polyamide fiber has been exposed to a heat treatment subsequent to said phenol/aldehyde treatment to further increase intrinsic viscosity thereof by at least 4%.
3. The treated polyamide fibers of Claim 1 wherein the phenol/aldehyde treatment is comprised of a bath containing at least one phenol and at least one aldehyde.
4. A treated paper machine pressing fabric comprising treated polyamide fibers having an initial amine end group concentration of at least 60 eq./10 6 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers being treated with a phenol/aldehyde treatment which comprises contacting the polyamide fibers with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time sufficient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
5. The treated paper machine pressing fabric as claimed in Claim 4, wherein said polyamide is a polyamide 6,6 and the intrinsic viscosity after said phenol/aldehyde treatment is not less than 1.3 dL./g.
6. The treated paper machine pressing fabric as claimed in Claim 4 wherein said aldehydes used in said treatment of said polyamide fibers are selected from the group consisting of formaldehyde, formaldehyde liberating compounds, oxaldehyde, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimelaldehyde, suberaldehyde, azelaldehyde and sebacaldehyde.
7. The treated paper making machine pressing fabric comprised of polyamide fibers as set forth in Claim 4 wherein the phenol/aldehyde treatment is comprised of a bath containing at least one phenol and at least one aldehyde.
8. The treated papermaking pressing fabric comprised of the polyamide fibers as set forth in Claim 4 said papermaking press fabric exhibiting a greater resistance to wear relative to a papermaking press fabric not incorporating said treated polyamides.
9. The treated papermaking pressing fabric as claimed in Claim 4 wherein said treated paper making pressing fabric has been exposed to a heat treatment subsequent to said phenol/aldehyde treatment to further increase intrinsic viscosity thereof by at least 4%.
10. The treated paper machine pressing fabric as claimed in Claim 4 wherein the polyamide fibers are subjected to the phenol/aldehyde treatment after formation into the papermaking press fabric.
11. A treated paper machine pressing fabric as set forth in Claim 4 wherein said treated paper machine pressing fabric exhibits a greater resistance to oxidizing chemicals which are used in the environments in which said treated paper making press fabrics are used, the greater resistance being relative to untreated polyamide fibers.
12. A treated paper machine pressing fabric comprising treated polyamide fibers, filaments and/or yarns having an initial amine end group concentration of at least 60 eq./106 g and an initial ratio of amine end groups to carboxy end groups greater than 1.0, the polyamide fibers, filaments and/or yarns being treated with a phenol/aldehyde treatment which comprises contacting the polyamide fibers, filaments and/or yarns with a solution of aldehyde at a temperature in excess of room temperature and a solution of phenol at a temperature in excess of room temperature, the treatments being carried out at a temperature and time sufficient to increase the intrinsic viscosity of the treated polyamide fibers by at least 4% when compared to the untreated polyamide fibers.
13. The treated paper machine pressing fabric as claimed in Claim 12 wherein said phenols used in said treatment of said polyamide fibers are selected from the group consisting of phenol, pyrocatechol, resorcinol, hydroquinone, pyrogallol and phloroglucinol.
14. The treated paper machine pressing fabric as claimed in Claim 12 comprised of polyamide fibers, filaments and/or yarns, said fabric exposed to a heat treatment subsequent to the phenol/aldehyde treatment, to further increase the intrinsic viscosity of said polyamide fibers, filaments and/or yarns by at least 4% compared to untreated polyamide fibers, filaments and/or yarns.
15. The treated paper machine pressing fabric as claimed in Claim 12 said press fabric being comprised of a base fabric and fiber layers attached to one or both sides of said base fabric.
16. The treated paper machine pressing fabric as claimed in Claim 12 wherein the polyamide fibers, filaments and/or yarns are subjected to the phenol/aldehyde treatment after formation into the paper making press fabric.
17. A treated paper machine pressing fabric as set forth in Claim 12 wherein said treated paper machine pressing fabric exhibits an improved resistance to oxidizing chemicals which are used in the environments in which said treated paper making press fabrics are used, the improved resistance being relative to untreated polyamide fibers.
18. The treated polyamide fiber as claimed in Claim 1 wherein the concentration of the phenol solution and aldehyde treatment solution does not exceed 2%.
19. The treated paper machine pressing fabrics as claimed in Claim 4 wherein the concentration of the phenol solution and aldehyde treatment solution does not exceed 2%.
20. The treated paper machine pressing fabrics as claimed in Claim 12 wherein the concentration of the phenol solution and aldehyde treatment solution does not exceed 2%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US33762789A | 1989-04-13 | 1989-04-13 | |
| US337,627 | 1989-04-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2013852A1 CA2013852A1 (en) | 1990-10-13 |
| CA2013852C true CA2013852C (en) | 2001-01-02 |
Family
ID=23321309
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002013852A Expired - Fee Related CA2013852C (en) | 1989-04-13 | 1990-04-04 | Paper machine pressing fabrics |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0392682B1 (en) |
| JP (1) | JPH072839B2 (en) |
| KR (1) | KR950013485B1 (en) |
| AT (1) | ATE126526T1 (en) |
| AU (1) | AU626659B2 (en) |
| CA (1) | CA2013852C (en) |
| DE (1) | DE69021612T2 (en) |
| DK (1) | DK0392682T3 (en) |
| ES (1) | ES2078304T3 (en) |
| FI (1) | FI101154B (en) |
| GR (1) | GR3017488T3 (en) |
| NO (1) | NO179711C (en) |
| ZA (1) | ZA902210B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69233624T2 (en) * | 1991-02-18 | 2007-04-26 | Albany International Corp. | Improvement on paper machine fabrics |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE456355A (en) * | 1939-10-07 | |||
| US2388676A (en) * | 1942-01-12 | 1945-11-13 | Du Pont | Synthetic linear polyamides |
| GB616549A (en) * | 1946-04-26 | 1949-01-24 | Dunlop Rubber Co | Improvements in and relating to the treatment of nylon thread |
| US3032441A (en) * | 1960-04-18 | 1962-05-01 | Huyck Corp | Open weave endless fabric and method for producing the same |
| DE1469347C3 (en) * | 1964-05-25 | 1974-01-24 | Filzfabrik Fulda Gmbh & Co, 6400 Fulda | Process for making abrasive articles |
| US4559196A (en) * | 1984-04-12 | 1985-12-17 | E. I. Du Pont De Nemours And Company | Process for improving the dyeability of nylon carpet fiber |
-
1990
- 1990-03-20 NO NO901281A patent/NO179711C/en unknown
- 1990-03-21 DE DE69021612T patent/DE69021612T2/en not_active Expired - Fee Related
- 1990-03-21 ES ES90303023T patent/ES2078304T3/en not_active Expired - Lifetime
- 1990-03-21 AT AT90303023T patent/ATE126526T1/en not_active IP Right Cessation
- 1990-03-21 EP EP90303023A patent/EP0392682B1/en not_active Expired - Lifetime
- 1990-03-21 DK DK90303023.7T patent/DK0392682T3/en active
- 1990-03-22 ZA ZA902210A patent/ZA902210B/en unknown
- 1990-03-23 FI FI901474A patent/FI101154B/en not_active IP Right Cessation
- 1990-04-04 CA CA002013852A patent/CA2013852C/en not_active Expired - Fee Related
- 1990-04-12 AU AU53266/90A patent/AU626659B2/en not_active Ceased
- 1990-04-12 JP JP2095205A patent/JPH072839B2/en not_active Expired - Lifetime
- 1990-04-13 KR KR1019900005131A patent/KR950013485B1/en not_active IP Right Cessation
-
1995
- 1995-09-21 GR GR950402605T patent/GR3017488T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ES2078304T3 (en) | 1995-12-16 |
| NO901281L (en) | 1990-10-15 |
| JPH032218A (en) | 1991-01-08 |
| KR900016515A (en) | 1990-11-13 |
| CA2013852A1 (en) | 1990-10-13 |
| FI901474A0 (en) | 1990-03-23 |
| DE69021612D1 (en) | 1995-09-21 |
| DE69021612T2 (en) | 1996-02-08 |
| EP0392682A3 (en) | 1991-03-13 |
| KR950013485B1 (en) | 1995-11-08 |
| EP0392682A2 (en) | 1990-10-17 |
| NO179711B (en) | 1996-08-26 |
| AU626659B2 (en) | 1992-08-06 |
| GR3017488T3 (en) | 1995-12-31 |
| JPH072839B2 (en) | 1995-01-18 |
| EP0392682B1 (en) | 1995-08-16 |
| NO179711C (en) | 1996-12-04 |
| ZA902210B (en) | 1990-12-28 |
| AU5326690A (en) | 1990-10-18 |
| NO901281D0 (en) | 1990-03-20 |
| DK0392682T3 (en) | 1995-12-11 |
| ATE126526T1 (en) | 1995-09-15 |
| FI101154B (en) | 1998-04-30 |
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