CA2003910A1 - Paper machine felts - Google Patents
Paper machine feltsInfo
- Publication number
- CA2003910A1 CA2003910A1 CA002003910A CA2003910A CA2003910A1 CA 2003910 A1 CA2003910 A1 CA 2003910A1 CA 002003910 A CA002003910 A CA 002003910A CA 2003910 A CA2003910 A CA 2003910A CA 2003910 A1 CA2003910 A1 CA 2003910A1
- Authority
- CA
- Canada
- Prior art keywords
- polyamide
- nylon
- batt
- article
- fibre
- 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
Classifications
-
- 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
- D21F7/00—Other details of machines for making continuous webs of paper
- D21F7/08—Felts
- D21F7/083—Multi-layer felts
Landscapes
- Paper (AREA)
- Artificial Filaments (AREA)
- Cleaning Implements For Floors, Carpets, Furniture, Walls, And The Like (AREA)
- Storage Of Web-Like Or Filamentary Materials (AREA)
- Sanitary Thin Papers (AREA)
- Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
Abstract
A B S T R A C T
PAPER MACHINE FELTS
The present invention relates -to an article of paper machine clothing formed from a fibrous material having a woven base and an optional batt layer attached thereto characterised in that said fibrous material comprises fibres of poly(undecanoamide)(polyamide 11) formed by the extrusion of a melt of polyamide 11 having an intrinsic viscosity of at least 1.0 dl/gram.
PAPER MACHINE FELTS
The present invention relates -to an article of paper machine clothing formed from a fibrous material having a woven base and an optional batt layer attached thereto characterised in that said fibrous material comprises fibres of poly(undecanoamide)(polyamide 11) formed by the extrusion of a melt of polyamide 11 having an intrinsic viscosity of at least 1.0 dl/gram.
Description
2~3~
P ER MACHINE FELTS
DESCRIPTION
This invention relates to paper machine felts. In a paper making machine, a slurry of paper making constituents referred to as ~furnish~ is deposited on a fabric or "wire" and the liquid constituents are drawn or extracted therethrough to produce a self-cohesive sheet which is then passed to the pressing and drying sections of the paper-making machlne. In the pressing section, the paper sheet is transported by ~ felt to a pair of rollers where the felt and paper sheet pass between the nip of the rollers to dewater and to dry the `: paper sheet. The paper sheet itself may contain alltypes of chemical finishes and will be, at the same time, subjected to an elevated temperature to aid the dewatering and drying thereof. The paper making fel~
;: 20 together with its sheet of paper tends therefore, to be subjected to immense pressure at elevated temperatures in a rigorous chemical environment.
:
P ER MACHINE FELTS
DESCRIPTION
This invention relates to paper machine felts. In a paper making machine, a slurry of paper making constituents referred to as ~furnish~ is deposited on a fabric or "wire" and the liquid constituents are drawn or extracted therethrough to produce a self-cohesive sheet which is then passed to the pressing and drying sections of the paper-making machlne. In the pressing section, the paper sheet is transported by ~ felt to a pair of rollers where the felt and paper sheet pass between the nip of the rollers to dewater and to dry the `: paper sheet. The paper sheet itself may contain alltypes of chemical finishes and will be, at the same time, subjected to an elevated temperature to aid the dewatering and drying thereof. The paper making fel~
;: 20 together with its sheet of paper tends therefore, to be subjected to immense pressure at elevated temperatures in a rigorous chemical environment.
:
3~
Paper making felts are generally produced by needling batt fibre to a woven backing which then supports the forming paper sheet as it passes through the press. In the nip of the press rolls, the batt fibres are bent and deformed under great pressure and at great frequency and hence the mechanical properties of the batt fibre are of consi~erable importance in these processes.
Polyamide 6 and polyamide 6,6 (PA 6 and PA 6,6,) have been used extensively in the manufacture of paper machine felts. These polymers are readily formed as fibres and their fibre characteristics can be controlled to allow production into acceptable felts. Many prior art proposals for the use of polyamide materials in ; 15 sheet and felt materials in general have been proposed.
For example, in British Patent Specification No.
1304732, there is a reference to the use of polyamide such as nylon 6, nylon 6,6, nylon 6.10, nylon 6 r 7, nylon 8, nylon 9, nylon 11 and nylon 12. The specification is concerned with the manufacture of fibrous sheet materials and is not specifically concerned with paper machine clothing.
3~
British Patent Specification No. 1329132 again relates to a known woven fabric for use, for example, as an interlining. Again, there is reference to the use of polyamide such as nylon 6, nylon 11, nylon 12 and copolyamides such as nylon 6,6 and copolymers of nylon 6 and nylon 6,6 with nylon 11 and nylon 12.
Prior British Specification No. 1585632 has been ; concerned with the manufacture of artificial leather and like materials and again the use of nylon 6, nylon 6,6, nylon 10 and nylon 11 and nylon 12 are disclosed together with various copolymers of different variations and combinations thereof.
In each of these cases, the nylon materials are used primarily for their inherent strength in a clothing or decorative assembly and would not be subjected to the agressive physical and chemical environment of a paper making machine.
2a European Patent Specification No. 000708 relates to a paper making machine felt comprising a woven heat set belt which in the machine and transverse direction comprises thermoplastic filaments, in which belt the filaments in at least one of the machine and transverse ; .
'' ' Z ~ ~ 3 ~ ~
directions are co-extruded and in which monofilaments have a core of polymer selected from nylon 6,6, polyethylene terephthalate and tetrapolymer of tera or isophthalic acid and a sheet of copolymer selected from nylon 11, nylon 12, nylon 6, nylon 6,10, nylon 6,12, polybutylene terephthalate and a large number of other materials.
In European Patent Specification No. 0070708, the materials are being employed primarily for their well known properties of strength and abrasion resistance.
Our co-pending European Application No. 88303201.3 shows that nylon 12 can be used in the construction of a felt for use in a paper making machine. Our researchers have shown quite surprisingly, that nylon 11 has properties which compare favourably with nylon 12 although this would not have been expected from the normal structure thereof. Polyamide 11 (polyundecanoamide) referred to - 20 in this specification as "PA 11" is well known in polymer technology and as an article of commerce.
Polyamide 11 was developed commercially for sources directed primarily to injection moulding applications.
~; The polyamide 11 homopolymer without cross-linking additives may be extruded to form a large number of lj .
.
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. .
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items and is ideally suited to the formation of monofilaments and fine denier continuous filament yarn.
While it would not be expected that this material would provide satisfactory properties required in a paper machine batt to provide the surface properties required, the present Applicants, unexpectedly, have found that batt materials of polyamide 11 when used in paper machine felts have superior durability and enhance recovery from compression and resistance to fibrillation compared with felt materials currently employed. In addition there is a superior chemical resistance to hydrolysis and rPsistance to degradation of physical properties by hypochlorite and other oxidation and we have found surprisingly that polyamide 11 can exhibit a 50-100% greater lifetime use in particularly hostile chemical and abrasive environments in paper making.
According to one aspect of the present invention, therefore, there is provided an article of paper machine clothing formed from a fibrous material having a woven ; base and an optional batt layer attached thereto characterised in that said fibrous material comprises fibres of poly(undecanoamide)(polyamide 11) formed by the extrusion of a melt of polyamide 11 having an intrinsic viscosity of at least 1.0 dl/gram.
2~9~
In a further aspect of the present invention the melt to be extruded may contain 0.2 to 1.0% by weiqht of an anti-oxidant and more preferably, 0.4 to 0.7% by weight.
The anti-oxidant may be selected from one or more of alpha-tocopherol, condensation products of diphenylamine and acetone and closely related structures derived from diphenylamine and compatible phenolic stablisers with amide functionality such, for example, as that made commercially available by Ciba Geigy under the trade name "IRGANOX 1098". Polyamide fibre containing approximately 0.5 to 0.6% by weight of anti-oxidant individually and separately or in combination results in a further enhancement of durability.
Polyarnide 11 resin of the appropriate instrinsic viscosity may be compounded during extrusion of monofilament or continuous filament by the addition of selec~ed anti-oxidants. Polyamide 11 monofilament in accordance with the invention may be extruded at temperatures across the barrel between 220C and 295C. The spinneret may be maintained at temperatures of approximately 300C. Nonofilament may be extruded with the drawdown of between 2.0 X and 4.5X in order to provide monofilaments of 0.1 - Q.25 mm ` 25 for manufacturing of Fourdrinier or other forming :
2~
fabrics. A particular utility for improved durability against abrasion, polyamide 11 monofilament may be also used advantageously as shute filament and/or warp filament in single, double or triple layer of press fabrics.
Surprisingly, it has been found that the incorporation of polyamide 11 high molecular weight monofilaments may be employed in Fourdrinier forming fabrics as warp or machine direction monofilaments. It is possible in accordance with the invention to prepare high durability all polyamide forming fabrics and avoid a mix of materials presently employed in which polyamide filaments must be alternatively inserted with polyester monofilaments in the shute direction in order to provide a measure of enhanced abrasion resistance without the existence of dimensional instability which normally results from the use of polyamide 6 or polyamide 6,6 material. The paper machine felts in accordance with the present invention have a low moisture re~ain and are relatively insensitive to physical properties in the presence of water.
~:
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Monofilaments may be extruded with variations in the process to deliver this and other desirable tensile properties for the weaving of base materials for needled nonwovens employed in the pressing section of a paper making machine. Monofilaments in large diameters may be employed in both the warp and shute directions in dryer screen applications.
Fine denier monofilaments of high molecular weight polyamide 11 may be extruded with anti-oxidant employing barrel temperatures within the range 215C to 277C with a spinneret temperature of approximately 270C. Continuous filament yarn of appropriate denier desirable for various layers of the batt of press felts can thus be extruded and later crimped and cut into staple fibre for batt manufacture and thereafter employed as a batt layer in press felts.
The advantage of the felts in accordance with the present invention is that such felts have superior durability due to enhanced resistance to fibre fibrillation and recovery from compression which result in compaction resistance. In addition to these advantages there is superior chemical resistance ~`~ 25 particularly resistance to hydrolysis and resistance to .~
. . :
., :
2~C~3~
degradation of physical properties by hypochlorite and other oxidation. Such fibres in press felts exhibit superior durability against abrasion damage experienced with papers containing fillers especially including clay or crushed limestone. Such felts exhibit at least 50-100% greater lifetime in use in particularly hostile chemical and abrasive environments. These results are quite surprising and outstanding and would not have been expected from our previous experience with incumbent polyamide materials.
Following is a description by way of example only of methods and with reference to the accompanying drawings of carrying the invention into effect:-In the drawings:-Figure 1 is a photomicrograph of a compression test of a standard PA 6,6 fibre used in the manufacture of a paper machine felt.
Figure 2 is a photomicrograph of a fibre in accordance with the present invention.
' ~ ' .
.' .
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Continuous filament of PA 11 was prepared according to the following procedure. Commercially available PA 11 w~s purchased as pellets from Rilsan Corp., New Jersey, having an intrinsic viscosity of 1.20 dl/g when determined in concentrated sulfuric acid. These polyamide pellets were vacuum dried at 80C for 16 hours to a final vacuum measured outside`the vacuum oven of 140 microns Hg. The pellets were transferred in a lQ manner so as to avoid absorption of moisture from the ; air to a hopper of a single screw extruder. The extruder was equipped with a 2.5 cm diameter low compression screw. The extruder was fitted with a filter pack of 55 micron nominal porosity. Downstream of the filter the extruder was fitted with a Zenith gear pu~p metering-the melt to a spinneret. The spinneret had 30 holes, each hole of diameter 0.5 mm. The extruder had a temperature profile ranging from 243C at the hopper throat to 271C at the pump with 5 zones of independent temperature monitoring and control. The spinneret was maintained at 270C. Filaments were extruded at approximately 195ft/min with a maximum draw-down such that the radial change was approximately 7-8/1 between spinneret and the first Godet. Yarn was .
.' :
~ ' , taken up on a cylinder attached to a Leesona winder after the Godet.
A typical fibre as-spun according to this procedure was S drawn in two stages with a third stage of relaxation all with heat to provide an overall 2.3X draw ratio. The first temperature of drawing was at 110C;
relaxation occurred in the 2nd stage at 160C.
Fibre from such a process was prepared to be 12.8 dpf (denier per filament). Fibre thus prepared had 4.6 gpd tenacity with an initial modulus of 26 gpd and an elongation at break of 45%. The stress-strain curve exhibited a deflection at an elongation of 10% at 3.5 gpd specific stress.
Such fibre was crimped in a heated stuffer box crimper to provide continuous yarn with a variable random crimp with approximately 4 crimps/cm. It was cut into staple of approximately 7.0 cm length. Such fibre was carded, lapped and needled into a press felt to provide a batt structure at an overall batt weight of approximately ; 1000 g/m2. A felt having such a batt structure exhibited at least 50% increased life in comparison to similar PA 6 felts when challenged with the same furnish on the same position on a paper machine.
~,;
:
:
.
Fibres were prepared as described in Example 1 with the following exceptions. Prior to drawing, pellets were tumbled with powdered Irganox 109~ (Ciba-Geigy) at a loading such that the blend would be 0.7% wt/wt.
Pellets appeared to be uniformly coated with the powder antioxidant prior to transfer to the hopper. W
analysis of the as spun fibre indicated a uniform concentration in several samples tested at a concentration of approximately 0.5% wt/wt.
Polyamide fibres produced in accordance with Example 1 were for~ed into a batt structure. Comparable filaments of a standard polyamide 6,6 currently used as an industry standard in the manufacture of paper machine clothing and commercially available under the trade reference T-100 supplied by DuPont was formed into a similar batt. Each of the batts was then incorporated by needling to the backing of a test felt to be run on a compression test machine. The felt containing the two `; batt samples was installed on the test machine and the machine was run to pass the felt between a pair of nip rollers with a predetermined nip loading. The test felt was run on the compression tester for one million ., .
,'' ' ~ ' . ` ~
.
. .
- 2~03~
compressions. After the one million compressions, the felt was removed and the batt examined under an electron microscope.
The results are shown in Figures 1 and 2 of the accompanying drawings. The results were assessed on a scale of 1 to 5 by inspection and comparison against prepared standards and given a ranking accordingly. The DuPont polyamide 6,6 was given a ranking of 4.0 on a scale of 1 to 5 in which 5 is the worst. An examination of the photomicrographs will show extensive fibrillation and fracture of the flattened filaments. By comparison examination of the polyamide 11 candidate batt shows a marked lack of fibrillation of the fibres and with only flattening and some transverse fracture of some of the fibres. It was given a ranking of 3.3 on a similar scale as above.
, The candidate fibre PA 11 was, therefore, in ~ 20 substantially better condition after a million ; compressions than the industry standard. This result ~ was a significant improvement over and above that which ; would have been expected for polyamide 11 filaments.
~.
, . . . I .
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Samples of commercial PA 6,6 fibre of instrinsic : viscosity 1.36; commercial PA 6 fibre of instrinsic viscosity 1.46; staple fibre of Examples 1 and 2 above with fibre instrinsic viscosities of 1.05 and 1.12 respectively were each subjected to 35% hydrogen peroxide aqueous solution at pH2 and at 60C for 24 hours. Retained IV results were as follows:
;
Candidates Initial IVFinal IV % Retained Example 1 PA 11 1.05 0.87 83%
Example 2 PA 11/AO 1.12 0.97 87%
PA 6 1.47 0.49 31%
PA 6,6 1.36 0.62 47 :' .
Paper making felts are generally produced by needling batt fibre to a woven backing which then supports the forming paper sheet as it passes through the press. In the nip of the press rolls, the batt fibres are bent and deformed under great pressure and at great frequency and hence the mechanical properties of the batt fibre are of consi~erable importance in these processes.
Polyamide 6 and polyamide 6,6 (PA 6 and PA 6,6,) have been used extensively in the manufacture of paper machine felts. These polymers are readily formed as fibres and their fibre characteristics can be controlled to allow production into acceptable felts. Many prior art proposals for the use of polyamide materials in ; 15 sheet and felt materials in general have been proposed.
For example, in British Patent Specification No.
1304732, there is a reference to the use of polyamide such as nylon 6, nylon 6,6, nylon 6.10, nylon 6 r 7, nylon 8, nylon 9, nylon 11 and nylon 12. The specification is concerned with the manufacture of fibrous sheet materials and is not specifically concerned with paper machine clothing.
3~
British Patent Specification No. 1329132 again relates to a known woven fabric for use, for example, as an interlining. Again, there is reference to the use of polyamide such as nylon 6, nylon 11, nylon 12 and copolyamides such as nylon 6,6 and copolymers of nylon 6 and nylon 6,6 with nylon 11 and nylon 12.
Prior British Specification No. 1585632 has been ; concerned with the manufacture of artificial leather and like materials and again the use of nylon 6, nylon 6,6, nylon 10 and nylon 11 and nylon 12 are disclosed together with various copolymers of different variations and combinations thereof.
In each of these cases, the nylon materials are used primarily for their inherent strength in a clothing or decorative assembly and would not be subjected to the agressive physical and chemical environment of a paper making machine.
2a European Patent Specification No. 000708 relates to a paper making machine felt comprising a woven heat set belt which in the machine and transverse direction comprises thermoplastic filaments, in which belt the filaments in at least one of the machine and transverse ; .
'' ' Z ~ ~ 3 ~ ~
directions are co-extruded and in which monofilaments have a core of polymer selected from nylon 6,6, polyethylene terephthalate and tetrapolymer of tera or isophthalic acid and a sheet of copolymer selected from nylon 11, nylon 12, nylon 6, nylon 6,10, nylon 6,12, polybutylene terephthalate and a large number of other materials.
In European Patent Specification No. 0070708, the materials are being employed primarily for their well known properties of strength and abrasion resistance.
Our co-pending European Application No. 88303201.3 shows that nylon 12 can be used in the construction of a felt for use in a paper making machine. Our researchers have shown quite surprisingly, that nylon 11 has properties which compare favourably with nylon 12 although this would not have been expected from the normal structure thereof. Polyamide 11 (polyundecanoamide) referred to - 20 in this specification as "PA 11" is well known in polymer technology and as an article of commerce.
Polyamide 11 was developed commercially for sources directed primarily to injection moulding applications.
~; The polyamide 11 homopolymer without cross-linking additives may be extruded to form a large number of lj .
.
~,. ,. ~
. .
- 2~
items and is ideally suited to the formation of monofilaments and fine denier continuous filament yarn.
While it would not be expected that this material would provide satisfactory properties required in a paper machine batt to provide the surface properties required, the present Applicants, unexpectedly, have found that batt materials of polyamide 11 when used in paper machine felts have superior durability and enhance recovery from compression and resistance to fibrillation compared with felt materials currently employed. In addition there is a superior chemical resistance to hydrolysis and rPsistance to degradation of physical properties by hypochlorite and other oxidation and we have found surprisingly that polyamide 11 can exhibit a 50-100% greater lifetime use in particularly hostile chemical and abrasive environments in paper making.
According to one aspect of the present invention, therefore, there is provided an article of paper machine clothing formed from a fibrous material having a woven ; base and an optional batt layer attached thereto characterised in that said fibrous material comprises fibres of poly(undecanoamide)(polyamide 11) formed by the extrusion of a melt of polyamide 11 having an intrinsic viscosity of at least 1.0 dl/gram.
2~9~
In a further aspect of the present invention the melt to be extruded may contain 0.2 to 1.0% by weiqht of an anti-oxidant and more preferably, 0.4 to 0.7% by weight.
The anti-oxidant may be selected from one or more of alpha-tocopherol, condensation products of diphenylamine and acetone and closely related structures derived from diphenylamine and compatible phenolic stablisers with amide functionality such, for example, as that made commercially available by Ciba Geigy under the trade name "IRGANOX 1098". Polyamide fibre containing approximately 0.5 to 0.6% by weight of anti-oxidant individually and separately or in combination results in a further enhancement of durability.
Polyarnide 11 resin of the appropriate instrinsic viscosity may be compounded during extrusion of monofilament or continuous filament by the addition of selec~ed anti-oxidants. Polyamide 11 monofilament in accordance with the invention may be extruded at temperatures across the barrel between 220C and 295C. The spinneret may be maintained at temperatures of approximately 300C. Nonofilament may be extruded with the drawdown of between 2.0 X and 4.5X in order to provide monofilaments of 0.1 - Q.25 mm ` 25 for manufacturing of Fourdrinier or other forming :
2~
fabrics. A particular utility for improved durability against abrasion, polyamide 11 monofilament may be also used advantageously as shute filament and/or warp filament in single, double or triple layer of press fabrics.
Surprisingly, it has been found that the incorporation of polyamide 11 high molecular weight monofilaments may be employed in Fourdrinier forming fabrics as warp or machine direction monofilaments. It is possible in accordance with the invention to prepare high durability all polyamide forming fabrics and avoid a mix of materials presently employed in which polyamide filaments must be alternatively inserted with polyester monofilaments in the shute direction in order to provide a measure of enhanced abrasion resistance without the existence of dimensional instability which normally results from the use of polyamide 6 or polyamide 6,6 material. The paper machine felts in accordance with the present invention have a low moisture re~ain and are relatively insensitive to physical properties in the presence of water.
~:
:
2~03~
Monofilaments may be extruded with variations in the process to deliver this and other desirable tensile properties for the weaving of base materials for needled nonwovens employed in the pressing section of a paper making machine. Monofilaments in large diameters may be employed in both the warp and shute directions in dryer screen applications.
Fine denier monofilaments of high molecular weight polyamide 11 may be extruded with anti-oxidant employing barrel temperatures within the range 215C to 277C with a spinneret temperature of approximately 270C. Continuous filament yarn of appropriate denier desirable for various layers of the batt of press felts can thus be extruded and later crimped and cut into staple fibre for batt manufacture and thereafter employed as a batt layer in press felts.
The advantage of the felts in accordance with the present invention is that such felts have superior durability due to enhanced resistance to fibre fibrillation and recovery from compression which result in compaction resistance. In addition to these advantages there is superior chemical resistance ~`~ 25 particularly resistance to hydrolysis and resistance to .~
. . :
., :
2~C~3~
degradation of physical properties by hypochlorite and other oxidation. Such fibres in press felts exhibit superior durability against abrasion damage experienced with papers containing fillers especially including clay or crushed limestone. Such felts exhibit at least 50-100% greater lifetime in use in particularly hostile chemical and abrasive environments. These results are quite surprising and outstanding and would not have been expected from our previous experience with incumbent polyamide materials.
Following is a description by way of example only of methods and with reference to the accompanying drawings of carrying the invention into effect:-In the drawings:-Figure 1 is a photomicrograph of a compression test of a standard PA 6,6 fibre used in the manufacture of a paper machine felt.
Figure 2 is a photomicrograph of a fibre in accordance with the present invention.
' ~ ' .
.' .
2~
Continuous filament of PA 11 was prepared according to the following procedure. Commercially available PA 11 w~s purchased as pellets from Rilsan Corp., New Jersey, having an intrinsic viscosity of 1.20 dl/g when determined in concentrated sulfuric acid. These polyamide pellets were vacuum dried at 80C for 16 hours to a final vacuum measured outside`the vacuum oven of 140 microns Hg. The pellets were transferred in a lQ manner so as to avoid absorption of moisture from the ; air to a hopper of a single screw extruder. The extruder was equipped with a 2.5 cm diameter low compression screw. The extruder was fitted with a filter pack of 55 micron nominal porosity. Downstream of the filter the extruder was fitted with a Zenith gear pu~p metering-the melt to a spinneret. The spinneret had 30 holes, each hole of diameter 0.5 mm. The extruder had a temperature profile ranging from 243C at the hopper throat to 271C at the pump with 5 zones of independent temperature monitoring and control. The spinneret was maintained at 270C. Filaments were extruded at approximately 195ft/min with a maximum draw-down such that the radial change was approximately 7-8/1 between spinneret and the first Godet. Yarn was .
.' :
~ ' , taken up on a cylinder attached to a Leesona winder after the Godet.
A typical fibre as-spun according to this procedure was S drawn in two stages with a third stage of relaxation all with heat to provide an overall 2.3X draw ratio. The first temperature of drawing was at 110C;
relaxation occurred in the 2nd stage at 160C.
Fibre from such a process was prepared to be 12.8 dpf (denier per filament). Fibre thus prepared had 4.6 gpd tenacity with an initial modulus of 26 gpd and an elongation at break of 45%. The stress-strain curve exhibited a deflection at an elongation of 10% at 3.5 gpd specific stress.
Such fibre was crimped in a heated stuffer box crimper to provide continuous yarn with a variable random crimp with approximately 4 crimps/cm. It was cut into staple of approximately 7.0 cm length. Such fibre was carded, lapped and needled into a press felt to provide a batt structure at an overall batt weight of approximately ; 1000 g/m2. A felt having such a batt structure exhibited at least 50% increased life in comparison to similar PA 6 felts when challenged with the same furnish on the same position on a paper machine.
~,;
:
:
.
Fibres were prepared as described in Example 1 with the following exceptions. Prior to drawing, pellets were tumbled with powdered Irganox 109~ (Ciba-Geigy) at a loading such that the blend would be 0.7% wt/wt.
Pellets appeared to be uniformly coated with the powder antioxidant prior to transfer to the hopper. W
analysis of the as spun fibre indicated a uniform concentration in several samples tested at a concentration of approximately 0.5% wt/wt.
Polyamide fibres produced in accordance with Example 1 were for~ed into a batt structure. Comparable filaments of a standard polyamide 6,6 currently used as an industry standard in the manufacture of paper machine clothing and commercially available under the trade reference T-100 supplied by DuPont was formed into a similar batt. Each of the batts was then incorporated by needling to the backing of a test felt to be run on a compression test machine. The felt containing the two `; batt samples was installed on the test machine and the machine was run to pass the felt between a pair of nip rollers with a predetermined nip loading. The test felt was run on the compression tester for one million ., .
,'' ' ~ ' . ` ~
.
. .
- 2~03~
compressions. After the one million compressions, the felt was removed and the batt examined under an electron microscope.
The results are shown in Figures 1 and 2 of the accompanying drawings. The results were assessed on a scale of 1 to 5 by inspection and comparison against prepared standards and given a ranking accordingly. The DuPont polyamide 6,6 was given a ranking of 4.0 on a scale of 1 to 5 in which 5 is the worst. An examination of the photomicrographs will show extensive fibrillation and fracture of the flattened filaments. By comparison examination of the polyamide 11 candidate batt shows a marked lack of fibrillation of the fibres and with only flattening and some transverse fracture of some of the fibres. It was given a ranking of 3.3 on a similar scale as above.
, The candidate fibre PA 11 was, therefore, in ~ 20 substantially better condition after a million ; compressions than the industry standard. This result ~ was a significant improvement over and above that which ; would have been expected for polyamide 11 filaments.
~.
, . . . I .
2~
- 14 ~
Samples of commercial PA 6,6 fibre of instrinsic : viscosity 1.36; commercial PA 6 fibre of instrinsic viscosity 1.46; staple fibre of Examples 1 and 2 above with fibre instrinsic viscosities of 1.05 and 1.12 respectively were each subjected to 35% hydrogen peroxide aqueous solution at pH2 and at 60C for 24 hours. Retained IV results were as follows:
;
Candidates Initial IVFinal IV % Retained Example 1 PA 11 1.05 0.87 83%
Example 2 PA 11/AO 1.12 0.97 87%
PA 6 1.47 0.49 31%
PA 6,6 1.36 0.62 47 :' .
Claims (5)
1. An article of paper machine clothing formed from a fibrous material having a woven base and an optional batt layer attached thereto characterised in that said fibrous material comprises fibres of poly(undecanoamide)(polyamide 11) formed by the extrusion of a melt of polyamide 11 having an intrinsic viscosity of at least 1.0 dl/gram.
2. An article as claimed in claim 1 characterised in that the melt on extrusion contains 0.2 to 1.0% by weight of an anti-oxidant.
3. An article as claimed in claim 1 or claim 2 characterised in that the anti-oxidant is selected from one or more of alpha-tocopherol, condensation products of diphenylamine and acetone, condensation products of diphenylamine and compatible phenolic stabilisers with amide functionality.
4. An article as claimed in claim 2 or claim 3 characterised in that the anti-oxidant is present in an amount of 0.4 to 0.7% by weight.
5. A press felt as claimed in any preceding claim characterised in that said fabric comprises a woven base and a batt fibre structure attached thereto, said batt fibre structure comprising fibres of poly(undecanoamide) formed by extrusion of a melt having an intrinsic viscosity of at least 1.0 dl/gram and a fibre ranking after one million compressions in the compression test herein described of less than 3.6.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB888827789A GB8827789D0 (en) | 1988-11-28 | 1988-11-28 | Paper machine felts |
GB8827789.2 | 1988-11-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
CA2003910A1 true CA2003910A1 (en) | 1990-05-28 |
Family
ID=10647613
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA002003910A Abandoned CA2003910A1 (en) | 1988-11-28 | 1989-11-27 | Paper machine felts |
Country Status (13)
Country | Link |
---|---|
EP (1) | EP0372769B1 (en) |
JP (1) | JPH04507267A (en) |
AT (1) | ATE96480T1 (en) |
AU (1) | AU627251B2 (en) |
BR (1) | BR8907793A (en) |
CA (1) | CA2003910A1 (en) |
DE (1) | DE68910285T2 (en) |
DK (1) | DK100891D0 (en) |
ES (1) | ES2045469T3 (en) |
FI (1) | FI92943C (en) |
GB (1) | GB8827789D0 (en) |
NO (1) | NO178469C (en) |
WO (1) | WO1990006397A1 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB9018987D0 (en) * | 1990-08-31 | 1990-10-17 | Albany Research Uk | Peek hot press felts and fabrics |
JP2534844Y2 (en) * | 1991-10-04 | 1997-05-07 | 敷島紡績株式会社 | Dryer canvas for papermaking |
DE19600162A1 (en) * | 1996-01-04 | 1997-07-10 | Bayer Faser Gmbh | Melt-spun, abrasion-resistant monofilaments |
DE19803493C1 (en) * | 1998-01-29 | 1999-04-29 | Inventa Ag | Paper machine felt |
EP0965665B1 (en) | 1998-06-18 | 2002-11-27 | Thomas Josef Heimbach Gesellschaft mit beschränkter Haftung & Co. | Monofilament and papermaking fabric made from the same |
DE19854732C1 (en) | 1998-11-26 | 2000-09-14 | Inventa Ag | Core-jacket bicomponent fiber and its use |
DE19930464C1 (en) * | 1999-07-01 | 2000-10-19 | Heimbach Gmbh Thomas Josef | Paper machine blanket, used in pressing of paper machine, has fleece layer based on synthetic fibers with low water absorption containing synthetic fibers with higher water absorption |
ATE495301T1 (en) | 2004-04-08 | 2011-01-15 | Ems Chemie Ag | PAPER MACHINE PRESS FELT AND METHOD AND APPARATUS FOR PRODUCING IT |
JP5542321B2 (en) * | 2008-11-20 | 2014-07-09 | ユニチカ株式会社 | Felt for paper machine |
JP2010174414A (en) * | 2009-01-30 | 2010-08-12 | Unitika Ltd | Fabric for bag material |
JP5792980B2 (en) * | 2011-04-05 | 2015-10-14 | 日本バイリーン株式会社 | Flame retardant fiber sheet |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1182672A (en) * | 1981-07-17 | 1985-02-19 | John E. Hansen | Paper-making belts of fused polymeric filaments |
GB8709067D0 (en) * | 1987-04-15 | 1987-05-20 | Albany Int Corp | Monofilaments |
-
1988
- 1988-11-28 GB GB888827789A patent/GB8827789D0/en active Pending
-
1989
- 1989-11-24 AU AU46396/89A patent/AU627251B2/en not_active Ceased
- 1989-11-24 DE DE89312241T patent/DE68910285T2/en not_active Revoked
- 1989-11-24 AT AT89312241T patent/ATE96480T1/en not_active IP Right Cessation
- 1989-11-24 WO PCT/GB1989/001410 patent/WO1990006397A1/en active IP Right Grant
- 1989-11-24 EP EP89312241A patent/EP0372769B1/en not_active Revoked
- 1989-11-24 JP JP2500246A patent/JPH04507267A/en active Pending
- 1989-11-24 BR BR898907793A patent/BR8907793A/en not_active IP Right Cessation
- 1989-11-24 ES ES89312241T patent/ES2045469T3/en not_active Expired - Lifetime
- 1989-11-27 CA CA002003910A patent/CA2003910A1/en not_active Abandoned
-
1991
- 1991-05-23 NO NO911984A patent/NO178469C/en not_active IP Right Cessation
- 1991-05-27 DK DK911008A patent/DK100891D0/en not_active Application Discontinuation
- 1991-05-28 FI FI912554A patent/FI92943C/en active
Also Published As
Publication number | Publication date |
---|---|
GB8827789D0 (en) | 1988-12-29 |
NO178469C (en) | 1996-04-03 |
AU627251B2 (en) | 1992-08-20 |
ATE96480T1 (en) | 1993-11-15 |
FI92943C (en) | 1995-01-25 |
NO911984L (en) | 1991-07-23 |
JPH04507267A (en) | 1992-12-17 |
ES2045469T3 (en) | 1994-01-16 |
NO911984D0 (en) | 1991-05-23 |
DE68910285T2 (en) | 1994-02-17 |
NO178469B (en) | 1995-12-27 |
DK100891A (en) | 1991-05-27 |
WO1990006397A1 (en) | 1990-06-14 |
BR8907793A (en) | 1991-08-27 |
AU4639689A (en) | 1990-06-26 |
EP0372769B1 (en) | 1993-10-27 |
DK100891D0 (en) | 1991-05-27 |
FI92943B (en) | 1994-10-14 |
FI912554A0 (en) | 1991-05-28 |
EP0372769A1 (en) | 1990-06-13 |
DE68910285D1 (en) | 1993-12-02 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
FZDE | Discontinued |