CA2365951C - Transfer strip - Google Patents
Transfer strip Download PDFInfo
- Publication number
- CA2365951C CA2365951C CA002365951A CA2365951A CA2365951C CA 2365951 C CA2365951 C CA 2365951C CA 002365951 A CA002365951 A CA 002365951A CA 2365951 A CA2365951 A CA 2365951A CA 2365951 C CA2365951 C CA 2365951C
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- CA
- Canada
- Prior art keywords
- transfer belt
- polymer layer
- belt
- polymer
- layer
- 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.)
- Expired - Fee Related
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
- B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
- B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/024—Woven fabric
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/026—Knitted fabric
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F3/00—Press section of machines for making continuous webs of paper
- D21F3/02—Wet presses
- D21F3/0209—Wet presses with extended press nip
- D21F3/0218—Shoe presses
- D21F3/0227—Belts or sleeves therefor
-
- 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
-
- 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
- D21F7/086—Substantially impermeable for transferring fibrous webs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/306—Resistant to heat
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/554—Wear resistance
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2413/00—Belts
Abstract
A transfer belt of a web press with an extended press gap for drying a paper web includes a support belt, in particular a woven or machined belt, a water-resistant polymer layer needled onto the support belt, and a fibrous surface layer arranged on the polymer layer.
Description
Transfer Belt Description The invention reiates to a transfer belt of a wet press with extended press gap for drying a paper web.
In wet presses of paper machines, a substantial portion of fluid contained in a fresh paper web is squeezed out between pressure rollers which form a press gap or, in the case of a so-called shoe press, between a press shoe and a counter roller. The paper web is usually guided by means of a continuous felt belt through the press gap in which the felt belt picks up fluid from the paper web and discharges it.
In a so-called tandein shoe press, dewatering is generally carried out between two press felts. In a new development, one of these press felts is replaced by a transfer belt, thus allowing dewatering output in the press gap (nip) to be improved and the gap between the last web press and the dry section of the paper machine (the so-called "dry section") to be closed. A
transfer belt should provide even presspre transfer within the press gap, offer good sheet delivery and not cause a substantial_-.
rehumidification of the paper web when nanning out of the press gap. Transfer belts used in practice are generally formed substantially of polyurethane and typically have a smooth, ground surface. It has been found that the paper delivery properties of these polyurethane transfer belts may not be entirely satisfactory; furthermorc, a paper web guided on them through the press gap typically has sur~aces of unequal smoothness ("two-sidedness"); this two-sidedness. is ordinarily viewed as a lack in quality in the case of graphic papers.
It is, therefore, an object of the invention to provide a transfer belt with improved application properties which, in particular, may have advantages in sheet delivery and surface textu're of a produced paper web.
This and other objects are satisfied by the present invention, which encompasses the basic idea of replacing a conventional transfer belt having a smooth surfaee facing toward the paper web with one having a fibrous surface which substantially matches the surface texture of the press felt located on the other side of the paper web. This substantially matches the surface texture on both surfaces of the : paper web and substantially dispose of the.
Translation ot PCT/EP00103024 2 disadvantageous two-sidedness.
It further incorporates the idea of reatising this felttike, fibrous surface texture of the transfer beit by a two or more component coating of a support belt, which is in particular woven or machined.
The aforementioned multiple component coating is needled thereto and so firmly joined by thermo=mechanical means, i.e. by a suitably chosen pressure and temperature application regime, that the composite matches the high mechanical loads a transfer belt is subjected in the web press seCtion of a paper machine. The aforementioned two or more component coating of the support which delivers the fibrous structured surface incorporates a relatively thick water repellent or only slightly water permeable polymer coating which is firmly joined to the support and a thin fibrous surface coating of non-melting (respectively melting at higher temperatures) and non-adhesive fibres which are themselves firmly joined to the polymer coating.
Preferably the transfer belt is insulated on both sides with a polymer layer in order to prevent the "carrying along" of water on the underside ot the belt.
Preferably 1ow metting polyotefins, potyamides, polyesters, polyacrylate or poyvinyis are used for the polymer layer.
The low melting polymer layer is formed after the needling process or during the fusing process by melting the corresponding fibres at temperatures in the range between 100 and 220 C, prefarably between 12010 and 1500 C. Through the application of pressure in the range between 5 kg/cm2 and 70 kg/Cm2 the softening temperature of the polymers can be reduced and the compression of the belt increased.
The polymer layer is formed in that meltable or melt-adhesive components within a feltlike Structure which is applied to the support belt are molten under pressure. This method of forming a polymer l8yer ensures a predetermined compressibility which substantially contributes to an even pressure transfer in the press gap and excellent deiivery properties during transfer of the paper web into the dry part. The low thickness of the fibrous surtace layer, which is arranged on the water repellent polymer layer, ensures excellent delivery properties at the transfer of the paper web in the dry part and minimum rehumidification which disposes of a grave disadvantage of press felts relative to the present transfer belt.
In a preferred embodiment, the support belt has in particular a multi-layered or laminated structure of fine twists in all layers; both in the longitudinal and transverse direction. The fine fibres may be monofilaments with a wire thickness between 0.1 and 0.3 mm which can be multiply twisted, filament twists or mixed twists out of monofilaments and multifilaments. When the support fabric has a scam, coarser monofilaments with a wire tlrickness between 0.3 and 0.8 mm may be used.
In another embodiment, afleece layer is provided on the side of the support belt facing away from the polymer layer which is firmly joined to the support belt and which can ftirther improve the pressure transfer properties in the press gap. When applying a plurality of fabric layers for the support web, then these are preferably jointly needled;
which produces in particular the fibre stnictiue for forming the polymer layer simultaneously with joining the fabric layers. .
The area of the t,ransfer belt which following the thermo-mechanical finish forms the polymer layer is structured in particular of fibres with a proportion of melting or melt-adhesive fibres of at least 10* though preferably in the region of between 25 and 100%.
The polymer layer is in a particutarly lasting design additionally reinforced by longitudinal and/or transverse threads additionally melted into the (needled) fibre structure.
The thickaess- of the polymer layer (or in the event two polymer layers are prasent, both polymer layers together) lies in the range between 20 and 90%, in particular betcveen 60 and 90%, of the total thickness of the transfer belt. In contrast thereto, the mean thickness of the fibrous surface layer lies only in the region between 1 and 10% of the total thickness of the trnnsfer belt. For practical reasons, the fibrous surface layer typically includes high temperature and friction resistant fibres, thus providing the opportunity for long life of both this surface layer and the tramsfer belt as a whole with constant texturing properties relative to the paper web_ The fibrous surface layer is formed preferably out of fibrous material with a melting point that lies 50' to 100' C higher than the melting point of the polymer layer out of e.g., polyester, polyamide or polycarbonate fibres, and/or with "non-melting" fibres such as PAC, aramid, TeflonTm or carbon fibres.
Due to high rigidity of a transfer belt, a design as a seamed belt.or as a seamed felt fabric =
which is fully sealed when pulled in is particularly preferred.
Particularly suitable for an embodiment of the support belt are polyamide, polycster, and aramid as well as other fibres of high expansion resistance and great strength and flexibility. Polyamide, polyester, polyolefins such as polypropylene, and polyvinyls such as PVC fibres, as well as selected copolymers thereof, but also'other readily available polymer fibres, can be used as rieedled fibres as well as for structuring the rear fleece.
The aforementioned fibres have thermoplastic properties and are thus suitable for forming a d.ense, water-resistant polymer layer betow ft surface of the transfer belt which is facing the paper web. Precise setting of desired properties is carried out in a conventional manner by selection of base polymers of suitable structure, in particular chain length and degree of bonding, and, if appropriate, by an addition of softeners and other additives.
When fonning the surface layer of thermoplastic fibres, it has to be observed in the production of thetransf.er belt that the thermo-mechanical treatment may be matched to the physico-chemical properties of the surface fibre material in such a maimer that substantially no fusing (with accompanying loss of tezture) of the fibres takes place at the surface.
One embodiment of the present invention provides a#ransfer belt for a papermaket's machine, oomprising;
-a support belt;
- a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibcrs needled into said support belt and subsequently 4a melted together; and - a surface layer with a feltlike texture overlying said polymer layer.
In another embodiment of the present invention there is provided a method of forming a transfer belt for use in a papermaking machine, comprising the steps of:
- providing a supportbelt;
- needling polymer fibers to said support belt;
- melting said polymer fibers to form a first water-resistant polymer layer that ovcrlies s~id support belt; and - attaching a surface layer with a feltlike texture to said polymer layer to overlie said polymer layer.
In yet another einbodiment of the present invention there provided a transfer belt for a papermaker's machine, comprising:
- a support belt;
- a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together, and - a surface layer with a feltlike texture overlying said polymer layer;
- wherein the first polymer layer has a thickness of between about 20% and 90 %
of the total tf-ickness, of the transfer belt, and the surface layer has a thickness of between about 1% and 10% of the total thickness of the transfer belt.
Advantages and practicalities of the invention are contained in the following description of preferred exemplary embodiments based on the figures.
Shown are, in Figure 1 a diagranimatical (not true to scale) cross-sectional illustration of a transfer belt according to a first embodiment of the present invention;
4b Figure 2 a diag,rarrunatical cross-sectional illustration of a second embodiment in the .. , present invention;
Figure 3 a diagrammatical cross-seotional illustration of a third embodiment in the present invention; and Figure 4 a diagrammatical cross-sectional illustration of a fovrth embodiment of the presentinven6on,and Figure 5 is a diagrammatic illustration of a web press into which a inventive transfer belt of the present invention can be inserted.
Figure 1 illustrates the structure of a transfer belt 10 with singko-layered support fabric 11 in cross-section.
Translation of PLT/EPOO/03024 5 To a surface of support fabric 11 is applied a polymer fibre structure 12, and on the surface facing away from the latter a short-fibre fleece 13. The polymer fibre structure 12 is needled onto fabric 11 and thus subjected to pressure and heat treatment, so that it is molten into a widely water repellent and compressible polymer layer 14 (not shown in the figure) whilst forming cavities of different size and shape.
The water permeability should lie in the range of 0 to 50 1/dm2.min, preferably below 30 I/dmZ.min under the conventional pressures in the press gap. A thin fibrous or feltlike surface layer (flocking) 15 of high temperature resistant and friction resistant fibres is arranged on the polymer fibre structure 12 or a therefrom produced polymer layer 14.
Support fabric 11 is made of high tensfle but relatively fine twists, for example of polyamide or p-aramide, ensuring tensile strength and running properties of the transfer belt which are virtually of the same value as those of conventional polyurethane belts. Therrno-mechanical treatment of the needled fibre structure 12 with a proportion of more than 50% meit-adhesive fibres ensures a development of a polymer water barrier layer of approximately 60% of the belt thickness with predetermined compressibility, which simultaneously fulfils a plurality of important functions. Firstly, it acts in the press gap as pressure distributing medium and ensures advantageous pressure transfer properties from the roller onto the paper web. Furthermore, it ensures that the humidity of the paper web can enter only to a limited extent into the depth of the transfer belt, so that only minimal rehumidification of the paper web takes place. Finally, it superposes the fibrous primary texture of flock 15 with a coarser but also feltlike random and pressure resistant secondary texture, thus ensuring together with the surface layer that the paper web which has been dried by means of the suggested transfer belt is practically free of two-sidedness_ A further embodiment of a transfer belt 20 illustrated in Fig. 2 substantially corresponds in its design with the first embodiment shown in Figure l and described above, so that the reference number are based on those of Fig. 1, and components denoted by corresponding reference numbers are not described again.
The main difference of this second embodiment from the first embodiment lies in the provisi0n of a two-layered support fabric 21 of which one fabric layer is linked to a fleece 23 whilst a polymer fibre struCture 22, whiCh is additionally fixed by pressure Transiation ot PGTJEPOO/03024 6 fusion to the upper fabric layer ot support fabric 21, is needled through both fabric layers. Polymer layer 24, which is established by thermo-mechanical treatment, below the belt surface, which is here again formed by flocks 25. extends here over a somewhat lesser proportion of the total thickness ot the transfer belt as support fabric 21, the two-layers of which serve to attain increased rigidity and tensile strength, itself claims a larger proportion of the total belt thickness.
in this embodiment, both fabric layers of support fabric 21 are essentialiy joined together by the needled polymer tibre structure 22 with a specified elastic dispiaceabiiity in the movement direction of the beli, which ensures high iong term stability of the laminated fabric structure. The other advantages correspond with those referred to above with reference to the embodiment of Fig. 1.
Fig. 3 shows an embodiment which is simplified relative to Fig. 1, and again matching components are given reference numbers based on Fig. 1. The main difference relative to the embodiment of Fig. 1 lies in dispensing with the rearsided fleece coating, as a result of which transfer belt 30 with fabric support 31 runs directly on the rollers of the wet press (also see Fig. 4 and the description further down).
Of all here described embodiments, transfer belt 30 is the most flexible and structurally simplest and thus, when using identical fibre materials, also the most cost-effective one. Dispensing with the fleece layer, which in the two other embodiments protects the support fabric from friction, then requires a selection of a sufficiently wear resistant material for the support fabric, for example poiyamide. The aforementioned materials are suitable as materials for polymer fibre structure 32, of which polymer iayer 34 is formed, and for surface coating 35. Surface layer 35 is, as in the other designs, in particular itself needled to polymer layer 34, and its thermo-mechanical treatment takes care of highly wear resistant fixing of the surface layer.
For transfer belt 30 illustrated in Fig. 3 is provided an arrangement of longitudinal threads 36 in polymer layer 34 in order to increase the tensile strength and for optimisation of distribution of tensile loads over the height of the beit.
Fig. 4 shows a modified transfer belt 10' with respect to Fig. 1 in which a polymer fibrous structure 12 is formed extending on both sides of the support fabric 11 and from which a first polymer layer 14a lying above the support fabric I i and a second polymer layer 14b lying underneath the support fabric are formed. This embodiment is advantageous in that the transfer belt here is insulated on both sides with a polymer layer and the entrainment of water on the underside of the transfer belt is Transiation of PCT/EP00/03024 7 thus prevented_ Fig. S is a basic diagram of the functions of a web press 100 which includes the inventive transfer belt. Fig. 4 is a basic diagram of a wet press 100 as part of a paper machine (not illustrated in its entirety). A paper web 101 runs between a first roller arrangement 102 (at the top of the illustration) and a second roller arrangement 103 (at the bottom of the illustration), of which the first roller arrangement 102 transports a press feit 104 and the second roller arrangement 103 transports a transfer belt 105, for example of one of the aforedescribed designs. Between press rollers 102A
of the first group of rollers and 103A of the second group of rollers is set a press gap 106 wherein paper web 101 is substantially dewatered between press felt 104 and transfer belt 105. Paper web 101 then runs into a dry party 107 (of which only a portion is shown in the figures), where it is guided by drying belt 108. After dewatering, press felt 104 and transfer belt 105 then return to the input of web press 100.
The inventive design is not restricted to the aforedescribed exemplary embodiments but is also possible in a plurality of modifications. In particular, the multi-component structure of the transfer belt is variable in many ways in dependence of concrete conditions of application, for example of a paper quality to be produced and operational parameters of the web press. Materials applied are not restricted to aforementioned plastic materials, but they can be replaced by other fibre materials of properties known to the expert.
g Translation ot PCT/EPOO/03024 List of Reference Numbers 10, 10'; 20; 30 Transfer Belt 11, 21, 31 - Support Fabric 12, 22, 32 - Polymer Fibre Structure 13, 23 - Fleece 14, 14a; 14b, 24; 34 - Polymer Layer 15; 25; 35 - Surface Layer 36 - Reinforcement Thread 100 Wet Press 101 Paper Web 102 - First Group of Rollers 102A - Press Roller 103 - Second Group of Rollers 103A - Press Roller 104 - Press Felt 105 - Transfer Beit 106 - Press Gap 107 - Dry Party 108 - Transport Belt
In wet presses of paper machines, a substantial portion of fluid contained in a fresh paper web is squeezed out between pressure rollers which form a press gap or, in the case of a so-called shoe press, between a press shoe and a counter roller. The paper web is usually guided by means of a continuous felt belt through the press gap in which the felt belt picks up fluid from the paper web and discharges it.
In a so-called tandein shoe press, dewatering is generally carried out between two press felts. In a new development, one of these press felts is replaced by a transfer belt, thus allowing dewatering output in the press gap (nip) to be improved and the gap between the last web press and the dry section of the paper machine (the so-called "dry section") to be closed. A
transfer belt should provide even presspre transfer within the press gap, offer good sheet delivery and not cause a substantial_-.
rehumidification of the paper web when nanning out of the press gap. Transfer belts used in practice are generally formed substantially of polyurethane and typically have a smooth, ground surface. It has been found that the paper delivery properties of these polyurethane transfer belts may not be entirely satisfactory; furthermorc, a paper web guided on them through the press gap typically has sur~aces of unequal smoothness ("two-sidedness"); this two-sidedness. is ordinarily viewed as a lack in quality in the case of graphic papers.
It is, therefore, an object of the invention to provide a transfer belt with improved application properties which, in particular, may have advantages in sheet delivery and surface textu're of a produced paper web.
This and other objects are satisfied by the present invention, which encompasses the basic idea of replacing a conventional transfer belt having a smooth surfaee facing toward the paper web with one having a fibrous surface which substantially matches the surface texture of the press felt located on the other side of the paper web. This substantially matches the surface texture on both surfaces of the : paper web and substantially dispose of the.
Translation ot PCT/EP00103024 2 disadvantageous two-sidedness.
It further incorporates the idea of reatising this felttike, fibrous surface texture of the transfer beit by a two or more component coating of a support belt, which is in particular woven or machined.
The aforementioned multiple component coating is needled thereto and so firmly joined by thermo=mechanical means, i.e. by a suitably chosen pressure and temperature application regime, that the composite matches the high mechanical loads a transfer belt is subjected in the web press seCtion of a paper machine. The aforementioned two or more component coating of the support which delivers the fibrous structured surface incorporates a relatively thick water repellent or only slightly water permeable polymer coating which is firmly joined to the support and a thin fibrous surface coating of non-melting (respectively melting at higher temperatures) and non-adhesive fibres which are themselves firmly joined to the polymer coating.
Preferably the transfer belt is insulated on both sides with a polymer layer in order to prevent the "carrying along" of water on the underside ot the belt.
Preferably 1ow metting polyotefins, potyamides, polyesters, polyacrylate or poyvinyis are used for the polymer layer.
The low melting polymer layer is formed after the needling process or during the fusing process by melting the corresponding fibres at temperatures in the range between 100 and 220 C, prefarably between 12010 and 1500 C. Through the application of pressure in the range between 5 kg/cm2 and 70 kg/Cm2 the softening temperature of the polymers can be reduced and the compression of the belt increased.
The polymer layer is formed in that meltable or melt-adhesive components within a feltlike Structure which is applied to the support belt are molten under pressure. This method of forming a polymer l8yer ensures a predetermined compressibility which substantially contributes to an even pressure transfer in the press gap and excellent deiivery properties during transfer of the paper web into the dry part. The low thickness of the fibrous surtace layer, which is arranged on the water repellent polymer layer, ensures excellent delivery properties at the transfer of the paper web in the dry part and minimum rehumidification which disposes of a grave disadvantage of press felts relative to the present transfer belt.
In a preferred embodiment, the support belt has in particular a multi-layered or laminated structure of fine twists in all layers; both in the longitudinal and transverse direction. The fine fibres may be monofilaments with a wire thickness between 0.1 and 0.3 mm which can be multiply twisted, filament twists or mixed twists out of monofilaments and multifilaments. When the support fabric has a scam, coarser monofilaments with a wire tlrickness between 0.3 and 0.8 mm may be used.
In another embodiment, afleece layer is provided on the side of the support belt facing away from the polymer layer which is firmly joined to the support belt and which can ftirther improve the pressure transfer properties in the press gap. When applying a plurality of fabric layers for the support web, then these are preferably jointly needled;
which produces in particular the fibre stnictiue for forming the polymer layer simultaneously with joining the fabric layers. .
The area of the t,ransfer belt which following the thermo-mechanical finish forms the polymer layer is structured in particular of fibres with a proportion of melting or melt-adhesive fibres of at least 10* though preferably in the region of between 25 and 100%.
The polymer layer is in a particutarly lasting design additionally reinforced by longitudinal and/or transverse threads additionally melted into the (needled) fibre structure.
The thickaess- of the polymer layer (or in the event two polymer layers are prasent, both polymer layers together) lies in the range between 20 and 90%, in particular betcveen 60 and 90%, of the total thickness of the transfer belt. In contrast thereto, the mean thickness of the fibrous surface layer lies only in the region between 1 and 10% of the total thickness of the trnnsfer belt. For practical reasons, the fibrous surface layer typically includes high temperature and friction resistant fibres, thus providing the opportunity for long life of both this surface layer and the tramsfer belt as a whole with constant texturing properties relative to the paper web_ The fibrous surface layer is formed preferably out of fibrous material with a melting point that lies 50' to 100' C higher than the melting point of the polymer layer out of e.g., polyester, polyamide or polycarbonate fibres, and/or with "non-melting" fibres such as PAC, aramid, TeflonTm or carbon fibres.
Due to high rigidity of a transfer belt, a design as a seamed belt.or as a seamed felt fabric =
which is fully sealed when pulled in is particularly preferred.
Particularly suitable for an embodiment of the support belt are polyamide, polycster, and aramid as well as other fibres of high expansion resistance and great strength and flexibility. Polyamide, polyester, polyolefins such as polypropylene, and polyvinyls such as PVC fibres, as well as selected copolymers thereof, but also'other readily available polymer fibres, can be used as rieedled fibres as well as for structuring the rear fleece.
The aforementioned fibres have thermoplastic properties and are thus suitable for forming a d.ense, water-resistant polymer layer betow ft surface of the transfer belt which is facing the paper web. Precise setting of desired properties is carried out in a conventional manner by selection of base polymers of suitable structure, in particular chain length and degree of bonding, and, if appropriate, by an addition of softeners and other additives.
When fonning the surface layer of thermoplastic fibres, it has to be observed in the production of thetransf.er belt that the thermo-mechanical treatment may be matched to the physico-chemical properties of the surface fibre material in such a maimer that substantially no fusing (with accompanying loss of tezture) of the fibres takes place at the surface.
One embodiment of the present invention provides a#ransfer belt for a papermaket's machine, oomprising;
-a support belt;
- a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibcrs needled into said support belt and subsequently 4a melted together; and - a surface layer with a feltlike texture overlying said polymer layer.
In another embodiment of the present invention there is provided a method of forming a transfer belt for use in a papermaking machine, comprising the steps of:
- providing a supportbelt;
- needling polymer fibers to said support belt;
- melting said polymer fibers to form a first water-resistant polymer layer that ovcrlies s~id support belt; and - attaching a surface layer with a feltlike texture to said polymer layer to overlie said polymer layer.
In yet another einbodiment of the present invention there provided a transfer belt for a papermaker's machine, comprising:
- a support belt;
- a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together, and - a surface layer with a feltlike texture overlying said polymer layer;
- wherein the first polymer layer has a thickness of between about 20% and 90 %
of the total tf-ickness, of the transfer belt, and the surface layer has a thickness of between about 1% and 10% of the total thickness of the transfer belt.
Advantages and practicalities of the invention are contained in the following description of preferred exemplary embodiments based on the figures.
Shown are, in Figure 1 a diagranimatical (not true to scale) cross-sectional illustration of a transfer belt according to a first embodiment of the present invention;
4b Figure 2 a diag,rarrunatical cross-sectional illustration of a second embodiment in the .. , present invention;
Figure 3 a diagrammatical cross-seotional illustration of a third embodiment in the present invention; and Figure 4 a diagrammatical cross-sectional illustration of a fovrth embodiment of the presentinven6on,and Figure 5 is a diagrammatic illustration of a web press into which a inventive transfer belt of the present invention can be inserted.
Figure 1 illustrates the structure of a transfer belt 10 with singko-layered support fabric 11 in cross-section.
Translation of PLT/EPOO/03024 5 To a surface of support fabric 11 is applied a polymer fibre structure 12, and on the surface facing away from the latter a short-fibre fleece 13. The polymer fibre structure 12 is needled onto fabric 11 and thus subjected to pressure and heat treatment, so that it is molten into a widely water repellent and compressible polymer layer 14 (not shown in the figure) whilst forming cavities of different size and shape.
The water permeability should lie in the range of 0 to 50 1/dm2.min, preferably below 30 I/dmZ.min under the conventional pressures in the press gap. A thin fibrous or feltlike surface layer (flocking) 15 of high temperature resistant and friction resistant fibres is arranged on the polymer fibre structure 12 or a therefrom produced polymer layer 14.
Support fabric 11 is made of high tensfle but relatively fine twists, for example of polyamide or p-aramide, ensuring tensile strength and running properties of the transfer belt which are virtually of the same value as those of conventional polyurethane belts. Therrno-mechanical treatment of the needled fibre structure 12 with a proportion of more than 50% meit-adhesive fibres ensures a development of a polymer water barrier layer of approximately 60% of the belt thickness with predetermined compressibility, which simultaneously fulfils a plurality of important functions. Firstly, it acts in the press gap as pressure distributing medium and ensures advantageous pressure transfer properties from the roller onto the paper web. Furthermore, it ensures that the humidity of the paper web can enter only to a limited extent into the depth of the transfer belt, so that only minimal rehumidification of the paper web takes place. Finally, it superposes the fibrous primary texture of flock 15 with a coarser but also feltlike random and pressure resistant secondary texture, thus ensuring together with the surface layer that the paper web which has been dried by means of the suggested transfer belt is practically free of two-sidedness_ A further embodiment of a transfer belt 20 illustrated in Fig. 2 substantially corresponds in its design with the first embodiment shown in Figure l and described above, so that the reference number are based on those of Fig. 1, and components denoted by corresponding reference numbers are not described again.
The main difference of this second embodiment from the first embodiment lies in the provisi0n of a two-layered support fabric 21 of which one fabric layer is linked to a fleece 23 whilst a polymer fibre struCture 22, whiCh is additionally fixed by pressure Transiation ot PGTJEPOO/03024 6 fusion to the upper fabric layer ot support fabric 21, is needled through both fabric layers. Polymer layer 24, which is established by thermo-mechanical treatment, below the belt surface, which is here again formed by flocks 25. extends here over a somewhat lesser proportion of the total thickness ot the transfer belt as support fabric 21, the two-layers of which serve to attain increased rigidity and tensile strength, itself claims a larger proportion of the total belt thickness.
in this embodiment, both fabric layers of support fabric 21 are essentialiy joined together by the needled polymer tibre structure 22 with a specified elastic dispiaceabiiity in the movement direction of the beli, which ensures high iong term stability of the laminated fabric structure. The other advantages correspond with those referred to above with reference to the embodiment of Fig. 1.
Fig. 3 shows an embodiment which is simplified relative to Fig. 1, and again matching components are given reference numbers based on Fig. 1. The main difference relative to the embodiment of Fig. 1 lies in dispensing with the rearsided fleece coating, as a result of which transfer belt 30 with fabric support 31 runs directly on the rollers of the wet press (also see Fig. 4 and the description further down).
Of all here described embodiments, transfer belt 30 is the most flexible and structurally simplest and thus, when using identical fibre materials, also the most cost-effective one. Dispensing with the fleece layer, which in the two other embodiments protects the support fabric from friction, then requires a selection of a sufficiently wear resistant material for the support fabric, for example poiyamide. The aforementioned materials are suitable as materials for polymer fibre structure 32, of which polymer iayer 34 is formed, and for surface coating 35. Surface layer 35 is, as in the other designs, in particular itself needled to polymer layer 34, and its thermo-mechanical treatment takes care of highly wear resistant fixing of the surface layer.
For transfer belt 30 illustrated in Fig. 3 is provided an arrangement of longitudinal threads 36 in polymer layer 34 in order to increase the tensile strength and for optimisation of distribution of tensile loads over the height of the beit.
Fig. 4 shows a modified transfer belt 10' with respect to Fig. 1 in which a polymer fibrous structure 12 is formed extending on both sides of the support fabric 11 and from which a first polymer layer 14a lying above the support fabric I i and a second polymer layer 14b lying underneath the support fabric are formed. This embodiment is advantageous in that the transfer belt here is insulated on both sides with a polymer layer and the entrainment of water on the underside of the transfer belt is Transiation of PCT/EP00/03024 7 thus prevented_ Fig. S is a basic diagram of the functions of a web press 100 which includes the inventive transfer belt. Fig. 4 is a basic diagram of a wet press 100 as part of a paper machine (not illustrated in its entirety). A paper web 101 runs between a first roller arrangement 102 (at the top of the illustration) and a second roller arrangement 103 (at the bottom of the illustration), of which the first roller arrangement 102 transports a press feit 104 and the second roller arrangement 103 transports a transfer belt 105, for example of one of the aforedescribed designs. Between press rollers 102A
of the first group of rollers and 103A of the second group of rollers is set a press gap 106 wherein paper web 101 is substantially dewatered between press felt 104 and transfer belt 105. Paper web 101 then runs into a dry party 107 (of which only a portion is shown in the figures), where it is guided by drying belt 108. After dewatering, press felt 104 and transfer belt 105 then return to the input of web press 100.
The inventive design is not restricted to the aforedescribed exemplary embodiments but is also possible in a plurality of modifications. In particular, the multi-component structure of the transfer belt is variable in many ways in dependence of concrete conditions of application, for example of a paper quality to be produced and operational parameters of the web press. Materials applied are not restricted to aforementioned plastic materials, but they can be replaced by other fibre materials of properties known to the expert.
g Translation ot PCT/EPOO/03024 List of Reference Numbers 10, 10'; 20; 30 Transfer Belt 11, 21, 31 - Support Fabric 12, 22, 32 - Polymer Fibre Structure 13, 23 - Fleece 14, 14a; 14b, 24; 34 - Polymer Layer 15; 25; 35 - Surface Layer 36 - Reinforcement Thread 100 Wet Press 101 Paper Web 102 - First Group of Rollers 102A - Press Roller 103 - Second Group of Rollers 103A - Press Roller 104 - Press Felt 105 - Transfer Beit 106 - Press Gap 107 - Dry Party 108 - Transport Belt
Claims (25)
1. A transfer belt for a papermaker's machine, comprising:
a support belt;
a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together; and a surface layer with a feltlike texture overlying said polymer layer.
a support belt;
a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together; and a surface layer with a feltlike texture overlying said polymer layer.
2. The transfer belt defined in claim 1, wherein said surface layer has a fibrous texture.
3. The transfer belt defined in claim 1, wherein said support belt comprises at least one woven fabric.
4. The transfer belt defined in claim 1, wherein said support belt comprises multiple layers.
5. The transfer belt defined in claim 4, wherein said multiple layers of said support belt comprise woven fabric layers.
6. The transfer belt defined in claim 1, further comprising a fleece layer overlying a surface of said support belt opposite said first polymer layer.
7. The transfer belt defined in claim 1, farther comprising a second polymer layer overlying said support belt on a side opposite said first polymer layer, said second polymer layer comprising polymer fibers needled into said support belt and subsequently melted together.
8. The transfer belt defined in claim 3, wherein said support belt includes a seamed fabric.
9. The transfer belt defined in claim 1, wherein said polymer fibres comprise at least 10% by weight thermoplastically deformable or melt-adhesive fibres.
10. The transfer belt defined in claim 1, wherein said polymer fibers comprise a mixture of hydrophilic and hydrophobic components.
11. The transfer belt defined in claim 1, wherein said first polymer layer has a thickness of between about 20% and 90% of the total thickness of the transfer belt.
12. The transfer belt defined in claim 1, wherein said first polymer layer further comprises at least one of fused longitudinal and transverse threads.
13. The transfer belt defined in claim 1, wherein said surface layer has a thickness of between about 1% and 10% of the total thickness of the transfer belt.
14. The transfer belt defined in claim 1, wherein said surface layer comprises fibers having a melting point at least 50° C. higher than the melting point of the fibres forming the polymer layer.
15. The transfer belt defined in claim 1, wherein said surface layer is formed of a material selected from the group consisting of: polyester; polyamide, polycarbonate; PAC, aramid, polytetraflouorether; and carbon fibers.
16. The transfer belt defined in claim 1, wherein said polymer fibers of said first polymer layer are formed of a material selected from the group consisting of:
polyolefins; polyamides; polyesters; and polyvinyls.
polyolefins; polyamides; polyesters; and polyvinyls.
17. The transfer belt defined in claim 1, wherein said first polymer layer is formed at a temperature between about 100° C and 220° C., and at a pressure between about kg/cm2 and 70 kg/cm2.
18. The transfer belt defined in claim 1, wherein said support belt includes monofilaments with a wire thickness between about 0.1 and 0.3 mm.
19. The transfer belt defined in claim 1, wherein said support belt comprises monofilaments with a wire thickness in the range between 0.3 and 0.8 mm.
20. A method of forming a transfer belt for use in a papermaking machine, comprising the steps of:
providing a support belt;
needling polymer fibers to said support belt;
melting said polymer fibers to form a first water-resistant polymer layer that overlies said support belt; and attaching a surface layer with a feltlike texture to said polymer layer to overlie said polymer layer.
providing a support belt;
needling polymer fibers to said support belt;
melting said polymer fibers to form a first water-resistant polymer layer that overlies said support belt; and attaching a surface layer with a feltlike texture to said polymer layer to overlie said polymer layer.
21. The method defined in claim 20, further comprising the step of attaching a fleece layer to said support belt.
22. The method defined in claim 20, further comprising the steps of:
needling polymer fibers to said support belt on a side opposite said first polymer layer, and melting said polymer fibers needling to form a second water-resistant polymer layer underlying said support belt.
needling polymer fibers to said support belt on a side opposite said first polymer layer, and melting said polymer fibers needling to form a second water-resistant polymer layer underlying said support belt.
23. The method defined in claim 20, wherein said melting step comprises applying beat and pressure to said polymer fibers sufficient to melt said polymer fibers.
24. The method defined in claim 23, wherein said melting step comprises applying heat to said polymer fibers at a temperature of between about 100° C.
and 220° C.
and 220° C.
25. A transfer belt for a papermaker's machine, comprising:
a support belt;
a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together; and a surface layer with a feltlike texture overlying said polymer layer;
wherein the first polymer layer has a thickness of between about 20% and 90%
of the total thickness of the transfer belt, and the surface layer has a thickness of between about 1% and 10% of the total thickness of the transfer belt.
a support belt;
a first water-resistant polymer layer overlying said support belt, said polymer layer comprising polymer fibers needled into said support belt and subsequently melted together; and a surface layer with a feltlike texture overlying said polymer layer;
wherein the first polymer layer has a thickness of between about 20% and 90%
of the total thickness of the transfer belt, and the surface layer has a thickness of between about 1% and 10% of the total thickness of the transfer belt.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19915891.6 | 1999-04-08 | ||
| DE19915891A DE19915891A1 (en) | 1999-04-08 | 1999-04-08 | Transfer belt |
| PCT/EP2000/003024 WO2000061864A1 (en) | 1999-04-08 | 2000-04-05 | Transfer strip |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2365951A1 CA2365951A1 (en) | 2000-10-19 |
| CA2365951C true CA2365951C (en) | 2008-07-08 |
Family
ID=7903918
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002365951A Expired - Fee Related CA2365951C (en) | 1999-04-08 | 2000-04-05 | Transfer strip |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP1169513B9 (en) |
| JP (1) | JP4865132B2 (en) |
| AT (1) | ATE275664T1 (en) |
| AU (1) | AU771158B2 (en) |
| BR (1) | BR0010661B1 (en) |
| CA (1) | CA2365951C (en) |
| DE (2) | DE19915891A1 (en) |
| ES (1) | ES2228505T3 (en) |
| MX (1) | MXPA01010136A (en) |
| WO (1) | WO2000061864A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10252841A1 (en) * | 2002-11-13 | 2004-06-03 | Voith Paper Patent Gmbh | Press arrangement and method for dewatering a fibrous web, in particular paper web |
| DE102004017818A1 (en) * | 2004-04-13 | 2005-11-03 | Voith Paper Patent Gmbh | dry arrangement |
| US7455752B2 (en) * | 2004-07-22 | 2008-11-25 | Albany International Corp. | Semi-permeable fabrics for transfer belt and press fabric applications |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60224892A (en) * | 1984-04-17 | 1985-11-09 | ヤマウチ株式会社 | Endless belt |
| JPS617118A (en) * | 1984-06-19 | 1986-01-13 | Yamauchi Rubber Ind Co Ltd | Endless belt |
| JP2739517B2 (en) * | 1990-06-27 | 1998-04-15 | 市川毛織株式会社 | Felt for papermaking |
| JP3080640B2 (en) * | 1990-07-20 | 2000-08-28 | 市川毛織株式会社 | Pressure belt for wide nip press |
| DE4226592A1 (en) * | 1991-08-23 | 1993-03-04 | Inventa Ag | PAPER MACHINE FELTS AND METHOD FOR PRODUCING THE SAME |
| GB9125889D0 (en) * | 1991-12-05 | 1992-02-05 | Albany Research Uk | Improvements in and relating to paper machine clothing |
| JP3045923B2 (en) * | 1994-03-28 | 2000-05-29 | 市川毛織株式会社 | Felt for papermaking |
| US5549967A (en) * | 1995-05-04 | 1996-08-27 | Huyck Licensco, Inc. | Papermakers' press fabric with increased contact area |
| DE29706427U1 (en) * | 1997-04-10 | 1997-06-05 | Huyck Austria | Flexible tape, especially for use in paper machines |
| JPH1150386A (en) * | 1997-06-30 | 1999-02-23 | Christian Schiel | Felt having improved both surface structure and used for producing paper and its production |
-
1999
- 1999-04-08 DE DE19915891A patent/DE19915891A1/en not_active Withdrawn
-
2000
- 2000-04-05 MX MXPA01010136A patent/MXPA01010136A/en active IP Right Grant
- 2000-04-05 AU AU42940/00A patent/AU771158B2/en not_active Ceased
- 2000-04-05 DE DE50009115T patent/DE50009115D1/en not_active Expired - Lifetime
- 2000-04-05 EP EP00922610A patent/EP1169513B9/en not_active Expired - Lifetime
- 2000-04-05 WO PCT/EP2000/003024 patent/WO2000061864A1/en active IP Right Grant
- 2000-04-05 JP JP2000610906A patent/JP4865132B2/en not_active Expired - Fee Related
- 2000-04-05 AT AT00922610T patent/ATE275664T1/en not_active IP Right Cessation
- 2000-04-05 ES ES00922610T patent/ES2228505T3/en not_active Expired - Lifetime
- 2000-04-05 CA CA002365951A patent/CA2365951C/en not_active Expired - Fee Related
- 2000-04-05 BR BRPI0010661-5A patent/BR0010661B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| AU4294000A (en) | 2000-11-14 |
| CA2365951A1 (en) | 2000-10-19 |
| WO2000061864A9 (en) | 2002-09-12 |
| JP4865132B2 (en) | 2012-02-01 |
| DE50009115D1 (en) | 2005-02-03 |
| MXPA01010136A (en) | 2003-07-14 |
| EP1169513B8 (en) | 2005-01-05 |
| BR0010661A (en) | 2002-02-05 |
| ES2228505T3 (en) | 2005-04-16 |
| DE19915891A1 (en) | 2000-10-12 |
| AU771158B2 (en) | 2004-03-18 |
| WO2000061864A1 (en) | 2000-10-19 |
| ATE275664T1 (en) | 2004-09-15 |
| BR0010661B1 (en) | 2010-10-19 |
| EP1169513A1 (en) | 2002-01-09 |
| EP1169513B9 (en) | 2005-01-26 |
| JP2002541357A (en) | 2002-12-03 |
| EP1169513B1 (en) | 2004-09-08 |
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| Date | Code | Title | Description |
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| EEER | Examination request | ||
| MKLA | Lapsed |
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