CN1042247C - Method of seam closure for sheet transfer and other paper processing belts - Google Patents

Abstract

The invention discloses a seam sealing method of a paper processing belt coated with a polymeric resin material, which mainly includes: providing a needle-seamable papermaking fabric; using a first pin to connect the fabric into an endless form; Polymerize the resin and allow it to cure; remove the first pin and cut along the seam and install the strip of first resin material on the paper machine; join the strip into endless form with the second pin and wrap The material covers the seam so that the compression properties there are the same as the rest of the belt. The invention also discloses a polymer-coated paper processing belt prepared by the above method.

Description

Paper conveyor belt of paper sorting machine and its seam sealing method

This invention is a continuation-in-part (CIP) of U.S. Patent Application SN 08/257565 filed June 9, 1994.

The present invention relates to a sheet handling belt for transferring a sheet between sections or between members of the same section such as presses of a press section of a paper machine on which the sheet is made, or for transferring The sheets are fed into other processes. In particular, the present invention relates to a transfer belt which, when installed on a paper machine, can be joined in endless form with a seam; Sealing method.

Currently, only such sheet handling belt transfer belts are commercially available. The transfer belt is designed not only to carry the sheet through the paper machine section so as to eliminate open threading from the paper machine; but also to easily transfer the sheet to another fabric or belt at certain desired locations. By definition, an open thread is one in which the sheet is passed from one part of the paper machine to another without support over a distance greater than the length of the cellulose fibers in the sheet and the sheet is prone to breakage. Elimination of open threading means eliminating the major cause of unscheduled downtime, ie breakage of the sheet at a location temporarily unsupported by a felt or other sheet support. Unsupported sheets are broken when they are passed from one point to another in the press section when disturbances occur in the flow of the pulp, or when the last press of the press section is passed to the dryer section May occur frequently. At these locations, the sheet typically contains at least 59% water, so the sheet is very weak and tends to break. Obviously, the presence of open threads will limit the maximum speed at which the paper machine can be run.

A successful sheet transfer belt must perform three key functions on a paper machine: a) remove the sheet from the press fabric without causing sheet instability problems; operation to ensure optimum dewatering and high quality sheets; and c) sheet receiving fabrics or belts that transfer the sheet from one press in the press section to the next press or multiple presses in the press section in a closed draw on, or transferred to the drying transfer fabric in the dryer section.

A sheet transfer belt that successfully performs these critical functions is disclosed in U.S. Patent No. 5,298,124, entitled "Transfer Belt," issued March 29, 1994, the teachings of which are incorporated herein by reference. The transfer belt shown therein has a surface topography characterized by a pressure-sensitive and recoverable roughness, so that when pressing in the nip, the roughness will be reduced, whereby the transfer belt and the sheet A thin, continuous film of water is formed between them to bond the sheet to the transfer belt as it exits the nip. When the original roughness is restored after exiting the nip, the sheet is transferred from the transfer belt to a permeable fabric such as a dry transfer fabric, possibly with the aid of a minimal amount of vacuum.

The paper transfer belts disclosed in that patent comprise a reinforcing substrate having a paper face and a back face, and a polymer coating comprising an equilibrium distribution of at least one polymer segment on the paper face. This equilibrium distribution takes the form of a polymer matrix which may comprise not only hydrophobic but also hydrophilic polymer segments. The polymer coating may also include a particulate filler. The reinforcing substrate is designed to resist longitudinal and transverse deformation of the transfer belt and may be a woven fabric, endless or sealable for sealing into endless form when installed on the paper machine. In addition, the reinforcing substrate may comprise a textile material and may have one or more layers of fiber batt joined by needling on its backside. By textile material is meant the natural or synthetic fibers and filaments used to make textiles. The backside can also be impregnated and/or coated with a polymeric material.

To date, such sheet transfer belts have been produced for paper mills in endless form, that is to say they have reinforcements that are either woven in endless form or joined in endless form before being coated with polymer material Substrate. However, it is time-consuming and complicated to install the endless transfer belt on the paper machine. When the transfer belt is installed or replaced, it goes without saying that the production of paper must be suspended. Since it is not possible to weave the belt through and around the various components of the machine, it must be inserted from the side of the machine. This needs to spend much more time and labor intensity than the installation of the opening belt, because paper machine components such as pressure rollers must be erected when the transfer belt is inserted into the gap between them from the side. Needless to say, providing a sheet transfer belt that can be sewn on the machine will greatly reduce the time and labor intensity required to install and replace the belt on the machine.

International Application No. WO 90/10165 discloses a creped fabric for drawing corrugated and smooth paper layers together through a creping machine so as to bond the layers together to form a creped paperboard.

International Publication WO 93/17161, which discloses International Application PCT/SE 93/00173, discloses an attachable belt comprising a textile provided with some thermoplastic material on at least one side and through at least part of the thickness of the textile. When heated and softened, the thermoplastic material will at least partially fill the weave structure of the textile. The edges of the ends of the strap have connecting meshes formed in the textile, and by the cooperation of the connecting meshes, connecting meshes are similarly formed in the jointed ends of the strap to form a detachable connection. In order to allow the belt to be easily installed on the paper machine and to provide that the connection area of the exit belt has the same properties as the other areas of the belt, without adding any plastic filler to the textile, the connection device cooperates along an area with the mesh which joins the ends of the textile , the width of the region is at least equivalent to the mesh range calculated from the end edge of the textile inward.

A difficulty that accompanies the provision of open-ended or sealable transfer tapes is that the seam areas leave impressions on the sheet similar to weft threads. As the sheet transfer belt guides the sheet through the press zone, where it makes direct contact with the sheet, the slightest differences in thickness, compressibility and surface hardness in the seam area of the belt will remain on the sheet. under the trace.

Accordingly, it is a primary object of the present invention to provide a sealable sheet transfer belt, and a method of sealing the seam region, whereby the performance of the seam region is substantially the same as that of the rest of the sheet transfer belt, resulting in Yes, the seam area will leave no mark on the sheet.

Another object of the present invention is to provide sheet transfer belts which are sealable, with the result that the time and labor required to install or replace such belts on a paper machine is reduced.

Yet another object of the present invention is to provide a sheet transfer belt that can be sealed so that existing paper machines can be more easily retrofitted, or adapted to incorporate the sheet transfer belt shown in US 5,298,124, whereby it can be obtained from Elimination of open threading on the paper machine.

Accordingly, the present invention encompasses several methods of sealing the seam area of a coated seamed belt after the sheet transfer belt has been rejoined into endless form on the paper machine. The object of the present invention is to completely close the seam while at the same time giving the seam the same compressive properties as the rest of the belt under normal nip loads. This closure technique also distributes the bending stresses concentrated at the coated connection lines. This improves the flex fatigue resistance of the connection.

Simply put there are two ways to fill the seam area of the prepared tape with a foamed polymer material on a non-paper side. The paper side of the tape may be of the same or a different polymeric material if desired, but does not necessarily have to be filled with foam. In one method, the foaming compound is foamed and cured under contact pressure using a heat source with a film plate and a suitable release medium. During the heating operation, the foaming compound expands and fills all voids, including the coated connecting lines. After curing, the heater is removed and the coated surface is finish ground to remove burrs. The chemistry of the foam and the geometry of the heater diaphragm determine the overall compressibility of the seam area in the nip.

In another method, the polymeric material is pre-foamed before it is applied to the seam area and cured by heating as above.

In another approach, the seam area may be covered with a solid foam strip of polymeric resin material, or with a fibrous strip of fibrous batting material. Each strip can be adhesively bonded to the seam area.

In yet another approach, the coated seamed base fabric may include multiple yarns in its machine direction. During seam preparation, multiple strands of yarn can be cut and aligned away from the paper side of the coated seamed tape to form a fibrous filler under the seam, replacing the lack of wadding in the seam area . A sealing operation is then carried out on the paper machine, for example by spraying on adhesive to hold the multiple yarns in place.

Coated tapes may have a structure whereby seam loops are positioned in the middle of the structure below the coating and above the base layer; coated tapes may include woven fabrics, needle punched fabrics of fibrous batt material , polymeric foams, coatings of polymeric resinous materials or other nonwoven structures, materials less compressible than needle punched fabrics of fibrous batt materials, or any combination thereof.

Alternatively, the bottom layer can be completely excluded. The coated surface (paper) may be sealed with a polymeric material, preferably non-foaming, room temperature curable, or heat curable more rapidly.

More specifically, the method of the present invention for seam-seaming in polymeric resin-coated paper-handling belts comprises joining a needle-seamable papermaker's fabric into endless form with a pin and coating the outer surface of the fabric with a polymeric resin material. surface (on paper). The polymeric resin material is then cured and optional surface finishing is performed, the pins are removed and the polymeric resin material is cut at the seam to give the just coated fabric its beginning form. The belt is then sent to the paper mill where it is rejoined into endless form with pins during installation on the paper machine. The seam is then covered on the uncoated side of the tape, ie the inner surface (not the paper side), with the seam area sealant. The encapsulating material may be a viscous paste comprising a polymeric material and a blowing agent. The joint is then gradually heated to a temperature at which the blowing agent degrades, thereby releasing gas and forming foam from the viscous slurry. The foam fills the voids of the seam and can also pass through the slits made when the coating material is cut. The joint is then reheated to the curing temperature of the foam. Curing may cause the kerf to be bonded closed, or may be bonded closed with a separate material.

Alternatively, the encapsulating material may be a pre-foamed polymeric material wherein the polymeric material is foamed prior to its application to the seam area. Pre-expansion can be accomplished by using blowing agents that degrade at or near room temperature. Low density fillers comprising expanded thermoplastic microspheres can be used in place of blowing agents. Once the pre-foamed polymeric material was applied to the seam area, it was cured as above with the same result.

Solid foam strips of polymeric material or fibrous strips of fibrous wadding material may be used as the encapsulating material instead of the liquid encapsulating material. The strips in both cases can be secured to the seam area by adhesive, while the slits can be glued closed with a separate material.

In addition, the coated seamed base fabric may include multiple yarns in its machine direction. Multiple strands of yarn can be cut and arranged under the seam to form a fibrous filler therein to replace the missing batt material. The fibrous filler can be held in place, for example with a spray adhesive.

The invention also includes tapes made according to these methods. Although in the following discussion the focus is on the seams of sheet transfer belts, the invention is also applicable to the seams of long nip presses (LNP) or any other polymer coated belts used in the paper industry.

The present invention enables those skilled in the paper machine field to control the compressibility of the seam to eliminate or at least minimize sheet marking in the nip. Another advantage of the present invention is that the distribution of foam or other material on the underside of the strip in the seam region reduces stress at the coating junction. Finally, sealing the coating joint prevents water penetration and possible premature belt failure due to delamination of the coating. The tape also reduces sheet marking caused by coated connecting wires.

The present invention will be described in more detail below with reference to the accompanying drawings.

Figure 1 shows a representative press arrangement for eliminating open threads in a paper machine, including transfer belts.

Figure 2 shows a cross-sectional view of a polymeric resin coated paper handling belt at a certain point in its manufacture.

Figure 3 shows a cross-sectional view of a polymeric resin coated paper handling belt at a subsequent point during its manufacture.

Figure 4 illustrates a method by which seams can be sealed after a polymeric resin coated paper handling belt has been installed on a paper machine, and Figure 4 is a cross-sectional view of the belt at that time.

Figure 5 shows a plan view of the seam region of a transfer belt sealed in accordance with an alternative embodiment of the present invention.

FIG. 6 is a side cross-sectional view taken along line 6-6' of FIG. 5. FIG.

Figure 7 shows an alternative method for sealing the seam.

Figure 8 shows another method of sealing the seam.

Figure 9 shows yet another method of sealing the seam.

FIG. 10 shows a variant of the method shown in FIG. 9 .

To illustrate the general background art, a representative press arrangement including a transfer belt to eliminate open tails in a paper machine is shown in FIG. 1 . Arrows in FIG. 1 indicate the direction of movement or rotation of the components shown therein.

In FIG. 1, the sheet 10, indicated by the dotted lines, begins to move to the right under the transfer fabric 12 which previously transfers the sheet 10 from a forming fabric, not shown.

The sheet 10 and transfer fabric 12 advance toward a first vacuum transfer roll 14 around which the sheet is drawn against a press fabric 16 . Suction in the first vacuum transfer roll 14 removes the sheet 10 from the transfer fabric 12 and onto the press fabric 16 . Transfer fabric 12 then advances from this transfer position and around first correction roll 18, and returns by means of auxiliary correction rolls, not shown, to a position where it can again receive sheet 10 from the forming fabric.

Next, the sheet 10 , carried by the press fabric 16 , advances toward the nip formed between the first press roll 22 and the second press roll 24 . As suggested by the dashed line within the circle representing the second press roll 24 in FIG. 1 , it may be grooved to provide receptacles for water removed from the sheet 10 in the nip 20 . A transfer belt 26 runs around first press roll 22 and is guided through nip 20 together with sheet 10 and press fabric 16 . In the nip 20 the paper sheet 10 is compressed between the press fabric 16 and the transfer belt 26 .

When exiting the nip 20, the sheet 10 is bonded to the surface of a transfer belt 26 whose surface is smoother than the press fabric 16, continuing from the nip 20 to the right of the figure, the sheet 10 and transfer belt 26 reach the second Vacuum transfer roller 28. The press fabric 16 is guided by means of the second correction roll 30, the third correction roll 32 and the fourth correction roll 34, and returns to the first vacuum transfer roll 14, where the press fabric 16 can receive the transfer fabric 12 again. Page 10. At the second vacuum transfer roll 28, the sheet 10 is transferred onto a drying fabric 36 which is guided adjacent the transfer roll. The drying fabric 36 advances the sheet 10 towards the first dryer cylinder 38 of the dryer section.

The transfer belt 26 advances away from the second vacuum transfer roller 28 to the right of the figure, reaches the fifth correction roller 40, around which the transfer belt is guided to the sixth correction roller 42, the seventh correction roller 44, and the eighth correction roller 46 and ninth correction roll 48, and eventually back to first press roll 22 and nip 20, where the transfer belt can again receive sheets from press fabric 16.

As can be seen in FIG. 1 , the transfer belt 26 also eliminates the open tail shown in this press arrangement, particularly where the sheet 10 is transferred from the press fabric 16 to the dryer fabric 36 . At all points where the sheet passes through the press arrangement shown in Figure 1, it is supported by support bodies. In addition, it should be noted that the sheet 10 is carried under the transfer belt 26 as it exits the nip 20 since the film of water on the transfer belt 26 is sufficient to absorb the sheet 10 .

In order to produce the seamed transfer belts of the present invention, one should proceed to obtain various OMS (on-machine-seamable) coated substrates and to be able to temporarily join them in endless form, the inner surface of the endless loop thus formed being the transfer belt of non-paper. A view of the seam area of such a press fabric is included in FIG. 2 .

Referring now specifically to FIG. 2 , seam region 50 of seamed OMS coated substrate 52 includes seaming loops 54 formed of longitudinal yarns 56 at the width edges of open-ended press fabric 52 . When such a coated substrate 52 is to be closed into endless form, the two ends are brought together, the sewing loops 54 at both ends are interleaved with each other to form the passage 58, and the pin 60 is passed through the passage 58 to seal the sewing loop 54 interlocked together. As shown in Figure 2, pin 60 may be a thick monofilament. In addition, the pin 60 can also be a multi-filament pin or a ply monofilament pin.

Figure 2 shows one coated substrate 52 that may be used. The coated substrate 52 includes transverse yarns 62 and fibrous batting material 64 sewn into a base fabric 62 formed by interweaving the longitudinal yarns 56 and the transverse yarns 62 . Additionally, in addition to the fibrous batting material 64, the bottom layer of the coated substrate 52 may also include, woven fabrics, polymeric foams, coatings of polymeric resinous materials, the same materials used on the paper side of the coated substrate 52. Or a different material, or other nonwoven structure, a material that is less compressible than the fabric of the sewn fibrous batting material, or any combination thereof. The use of a less compressible material than the sewn fabric of fibrous batting material is an alternative to making the seam more compressible to achieve similar performance between the seam area and the rest of the sheet transfer belt.

Alternatively, the bottom layer can be completely eliminated. In this case, when the coated seamed belt is installed on the paper machine, the coated surface (paper side) should be sealed with a polymeric material, preferably a non-foaming material; said material can be cured at room temperature, Or it can cure more quickly under heating.

As mentioned above, the coated substrates 52 are temporarily joined in endless form on suitable devices in the production plant, the outer surface of the endless loop thus formed being the paper side of the transfer belt, with the result that the belt can be moved in a manner similar to its Placed under longitudinal tension for support while running on the paper machine.

Under such conditions, the outer surface of the closed loop formed by the coated substrate 52 is coated with a polymeric coating 68 comprising a balanced distribution of segments of at least one polymer such that the formation may include hydrophobic and Polymer matrix for hydrophilic polymer segments. The polymeric coating 68 may also include particulate fillers 70 as disclosed in US 5,298,124.

Coating 68 is then cured and ground to provide transfer belt 72 including seam region 50 having a uniform thickness and desired surface topography.

At this point, the transfer belt 72 can be turned over (turned inside out) if the length and width of the transfer belt 72 allow and without causing any damage to it. In addition, the operations to be described next can be performed inside the closed loop formed by the conveyor belt 72 as long as means are provided for the worker to operate in the closed loop without damaging the conveyor belt 72 .

In both cases, the pin 60 is removed and the transfer strip 72 is folded over at the seam area 50 as shown in FIG. 3 . That is, the transfer belt 72 is folded in such a way that the coating 68 is on the inside of the fold. The function of the fold is to remove the sewing rings 54 from the staggered state and make them into two upright spaced apart parallel sewing rings 54 as will be described. Between the two parallel sewing rings is a portion 74 of the coating 68 which is cut open by using a paring knife between the two parallel sewing rings 54, thereby enabling transfer without any damage to the sewing rings 54. Band 72 returns to the beginning form.

The transfer belt 72 is packaged in this start-up state and sent to the paper mill for installation on the paper machine, for example as shown in Figure 1, in the same way as the OMS press fabric. It will be noted here again that the conveyor belt is indicated by the reference numeral 26 in FIG. 1 .

Now, returning to FIG. 1 , a seamable transfer belt 72 is installed on the paper machine in place of the endless transfer belt 26 having the polymer-coated side 68 facing outward. Yarns more flexible than thick monofilament pin 60 may be used as the final pin. It is still necessary to ensure that the seam area 50, in particular the portion 74 of the polymer coating 68 which is cut open to the transfer belt 72, does not mark the sheet 10 produced on the paper machine.

Referring to Figure 4, the seam region of the transfer belt 72 is shown in the state shown therein when the pin 76 is used to join the transfer belt 72 in endless form on the paper machine. The slit 78 is in the polymer coating 68 immediately above the sewing ring 54 and, secondarily, the crack 80 is in the fibrous batt 64 directly below the sewing ring 54 . The combination of loops and pins makes the seam area 50 slightly different from the rest of the seamable transfer belt 72, and creates a possibility that the seam area 50 may cause the paper sheet to be in contact with it. mark.

The pin 76 may be a thick monofilament pin, a multifilament pin, a plied multifilament pin, a plied monofilament pin, or a composite pin including these pins.

The foam produced by mixing a liquid polymeric resin material and a foaming agent to form a viscous polymer and heating and curing the viscous slurry is used to fill and bond the seam area 50 and the slit 78 . Solvent-free polyurethane compositions, such as Uniroyal's Adiprene L-100, or compositions based on polyether prepolymers can be used for this purpose. The following are examples of solvent-free polyurethane compositions that can be used for this purpose. The component weight ( %) polyether/dioxyl toluene (TDI) polyurethane pre-polymer (4.1 % NCO) 76.9 obstructive tubamine (equivalent -217) 15.4 heating nucleothamidine (foaming agent) 7.7

In addition, other components such as fillers, plasticizers and catalysts may be added if desired. A blowing agent, usually a solid particulate material, which degrades upon heating to a characteristic temperature to release gas almost instantaneously, is mixed with a liquid polymeric resin material. The activity of the blowing agent at this temperature is generally lower than the activity at the curing temperature of the polymeric resin material. For example, the temperature at which the blowing agent degrades (or foams) may be 115°C, while the temperature at which the polymeric resin material cures may be 130°C; this is the corresponding temperature for Adiprene L-100. The foaming agent foams and expands the viscous slurry, filling the voids in the seam area 50 and even passing through the slit 78 . In this manner, the slits 78 can be bonded together and the compressibility and thickness of the seam region 50 can be made the same as the remainder of the transfer belt 72 .

The viscous slurry that produces foam 82 is preferably first applied to the non-paper side or inside of the seam area 50 of the transfer belt 72 at a time on the paper machine that is easily accessible to mill workers. For example, inclusion in the vicinity of seventh correction roller 44 in FIG. 1 may provide such easy access. The viscosity of the viscous slurry producing foam 82 is preferably adjusted such that it can be applied easily regardless of the orientation of the surface to be coated (lateral, vertical, above, below, etc.).

The viscous slurry is preferably applied to the non-paper seam of the transfer belt 72 at a distance on both sides of the seam, such as 0.64 cm, so that the bending stress can be distributed across the seam area 50, rather than concentrated at the slit 78 places.

Once the non-paper seam area 50 of the seamable transfer belt 72 has been covered with the adhesive paste, this area can be covered with a material 84 to which the cured foam 82 (derived from the adhesive paste) does not adhere. Material 84 may be, for example, heat-resistant release paper, Teflon-coated fiberglass tape, and other materials.

Alternatively, the paper surface of the seam region 50 of the seam transfer belt 72 may be coated with a viscous slurry that produces the foam 82, or may be coated with other polymeric coating materials such as that used to provide the coating 68. Cloth, to fill any cracks in the slits 78 Likewise, once the seam area 50 of the paper surface of the seamable transfer belt 72 has been coated in both ways, the foam 82 (obtained from a viscous slurry) can be used to ) or other polymeric coating material to which the material 84 does not bond covers the area.

A heat source may be used to foam the viscous slurry and cure the foam 82 . For example, the heating strip 86 may be formed from an aluminum plate having a thickness of typically 1.27 cm and a width sufficient to completely cover the seam area 50 in the direction of travel of the belt. The heating strip 86 includes a heating element whereby the heating strip can be ramped from room temperature to the temperature at which the foam solidifies and above.

The two heating strips 86 are compressed against both sides of the seam area 50 so that the thickness of the seam area 50 is the same as the rest of the transfer belt 72 . Where the device raises the heating strip from room temperature to a foaming temperature at which the foaming agent included in the viscous slurry degrades and foams the slurry, forcing the slurry into the interstices of the seam zone 50, Heating is continued above the foaming temperature to the curing temperature of the polymeric resin material at which the material cures almost instantaneously. Preferably, the curing temperature is maintained for a time sufficient to ensure completion of the trial curing process.

Instead of using two heating strips 86 as described above, a heated slide 100 can be pulled through the seam area 50 . As shown in Figure 5, across the width of the transfer belt 72 along the seam zone 50, the foaming agent included in the viscous slurry degrades and foams the slurry to force the slurry into the interstices of the seam zone 50 and achieve polymerization The curing temperature of the resin is maintained at a rate sufficient to ensure the completion of the curing process by pulling the heating slide 100 . During this process, support is preferably provided under the seam region 50 so that the heating slide 100 can compress the seam region 50 to ensure that the thickness of the seam region 50 can be the same as the rest of the transfer belt 72 .

FIG. 6 is a side cross-sectional view taken along line 6-6' of FIG. 5. FIG. The heated sled is pulled along the seam region 50 across the transfer belt 72 by a rope. Although the tension of the transfer belt 72 provides sufficient support for the slide 100 , a support 104 may be provided beneath the seam area 50 so that the heated slide 100 can be compressed against the seam area 50 .

A viscous slurry having a long pot life at room temperature can be used so that the slurry can be applied incrementally along the seam without the seam being completely transected across the conveyor belt. The long pot life allows the paste to remain for a long time without changing its properties. If the slurry has a long pot life, the heating strip 86 does not need to be as wide as the transfer belt 72. As mentioned above, it can be used step by step along the joint as the heating slide 100 is used, so that the joint will be welded according to the method of the present invention. seam closure.

After curing, any material 84 applied to the non-paper and/or paper side of the seam area 50 is removed and the transfer belt may be moved so that the seam area 50 is on a roller such as the seventh correcting roller 44 of FIG. 1 . At this point, the surface of the polymeric coating 68 is smoothed by light sanding to remove any joint filler protruding beyond the joint area.

Additionally, additional materials may be used to bond the slits. The following are examples of recipes that can be used as additional materials:

Component Weight (%)

Polyether/TDI polyurethane prepolymer (4.1% NCO) 76.9

Hindered aromatic amines (eq-217) 15.4

Kaolin 7.7

As an alternative to using a viscous slurry obtained by mixing a liquid polymeric resin material with a blowing agent as described above and adding the viscous slurry to the seam region 50 to form the foam 82, a pre-foamed liquid polymeric resin can be used material to replace viscous paste. "Pre-foamed" means that the material has been foamed before it is applied to the seam region 50 . This foaming can be accomplished by using endothermic nucleating agents (blowing agents) that degrade at or near room temperature. Such blowing agents are readily available and well known to those of ordinary skill in the art.

In the case of the solvent-free polyurethane composition used to fill the seam region 50 described above, such blowing agents may be replaced by low-density fillers. Particular low density fillers are in the form of thermoplastic microspheres of hydrocarbon-containing liquids. These microspheres are puffed by heating and they remain puffed when cooled. Even after puffing, they are tiny, about a micron in diameter, and have a very low density. The use of a variety of low density fillers allows the professional to precisely control the density of foam applied to the joint area. That is, the microspheres can be gradually added to the mixture until the desired density value is reached. An example of such a low density filler is Expancel DE 551, which consists of pre-expanded thermoplastic hollow microspheres added to a "pre-foamed" polymeric material used to cover joints.

As another alternative, a solid foam strip 88 may be applied over the seam area 50 as shown in FIG. 7 . The solid foam strip 88 may be made from a so-called "pre-foamed" liquid polymeric resin material as described above, or from a liquid polymeric resin material including low density fillers (microspheres). The solid foam strip 88 may be thermoplastic or thermoset, depending on the manner in which the curing agent included in the liquid polymeric resin material interacts with the end groups of the polymer chains. When strip 88 is thermoplastic, it may be bonded to seam region 50 by means of a heat source such as heated strip 86 . Alternatively, strip 88 may also be bonded to seam area 50 with the same adhesive as described above for bonding slit 78; the adhesive may be pre-applied to strip 88. When strip 88 is thermoset, it may be bonded to seam area 50 with the same adhesive as described above for bonding slits 78 . Finally, the strip 88, whether thermoplastic or thermoset, may be provided with a heat-activated adhesive that bonds to the seam region 50. An example of a heat activated adhesive that can be used for this purpose is anhydrous thermoplastic polyurethane (eg Estane resin) added as a liquid cement.

As another alternative, as shown in FIG. 8, a fiber strip 90 of fibrous batting material may be bonded to the seam region 50 in place of the strip 88 of solid foam. The adhesive may be one that bonds the slits 78 as described above.

In each of these alternatives, additional materials such as those given by way of example above may be used to bond the slits 78 . A layer of adhesive may be applied to the slits 78 before any liquid polymeric resin material 82, pre-foamed solid strips 88 or fibrous strips 90 are applied to the seam area on the non-paper side of the transfer belt.

Yet another alternative is illustrated in FIGS. 9 and 10 . In both figures, the multiple yarns are oriented in the machine direction of base fabric 66 . The multi-ply yarns may be multifilament, spun yarn or textured multifilament.

It should be noted that there is a gap 106 in the fibrous batting material 64 at the seam region 50 . During preparation of the seam region 50, the plurality of yarns 108 are cut and positioned away from the polymeric coating 68 to form a fibrous filler under the seaming loop 54 to replace the missing fibrous batting material in the gap 106 64. As shown in Figures 9 and 10, the multi-ply yarns 108 can come from one or both sides of the seam area 50, preferably by weaving the multi-ply yarns into the base fabric 66 during weaving, but they can also be Needles are added after weaving, for example during tufting.

After installation on the paper machine, the multiplicity of yarns 108 can be held in place using, for example, a spray phylloline adhesive such as a commercially available acrylic aerosol adhesive. The slit 78 in the polymer coating 78 can be closed using a polymeric material, preferably a material that has not yet been foamed. Polymeric materials that are curable at room temperature as well as materials whose curing can be accelerated by heating can be used for this purpose.

In all of the foregoing embodiments of the invention, not only non-foamed polymeric materials that cure by heat or room temperature, but also conventional UV light and non-foamed polymeric materials that are cured by means known to those of ordinary skill in the art may be used .

It will be appreciated that the purpose of each of these alternatives is primarily to encapsulate the looped seam and provide an encapsulated seam with the compressive properties of the remainder of the transfer belt. The method chosen in any given situation will be the one that can be carried out by the mill workers in the shortest time, thereby minimizing the time for setting up the machine rather than for papermaking.

Modifications to the foregoing will be apparent to those of ordinary skill in the art and such modifications do not extend the invention beyond the scope of the appended claims.

Claims (62)

1. the page of a polymer resin coating is handled the method for closing of the seam of band, comprises the steps:

The papermaking fabric that provides pin to sew up, described fabric have paper, non-paper and at the suture ring at two widthwise edges places that form seam;

Utilize first fibula, by guide described first fibula pass by described suture ring at described two widthwise edges places determined passage when interlaced with each other, the papermaking fabric that described pin can be sewed up connects into endless form;

The one side of described papermaking fabric is coated with first polymeric resin material;

Solidify described first polymeric resin material, the page that produces described polymer resin coating is handled band;

Take out described first fibula;

Cut first polymeric resin material of described curing at described seam crossing, thereby place described band with the form at beginning;

Described band is installed on the paper machine;

Utilize second fibula, but by guide described second fibula pass by described suture ring at described two widthwise edges places of described pin seamed papermaking fabric determined passage when interlaced with each other, described band is connected into endless form, thus, described first polymeric resin material has the joint-cutting in abutting connection with described suture ring; With

Utilize encapsulating material, topped described seam on uncoated of described band, the compression performance with the other parts of described band is identical basically with the compression performance that causes described seam.

2. the method for claim 1, wherein said first fibula is thick monofilament fibula.

3. the method for claim 1, wherein said first fibula is the multifilament fibula.

4. the method for claim 1, wherein said first fibula is the plied monofilament fibula.

5. the method for claim 1, wherein said second fibula is thick monofilament fibula.

6. the method for claim 1, wherein said second fibula is the multifilament fibula.

7. the method for claim 1, wherein said second fibula is the plied monofilament fibula.

8. the method for claim 1, wherein said second fibula is the compound fibula that comprises thick monofilament fibula.

9. the method for claim 1, wherein said second fibula is the compound fibula that comprises the multifilament fibula.

10. the method for claim 1, wherein said second fibula is the compound fibula that comprises the plied monofilament fibula.

11. the method for claim 1, but wherein said application step on the paper of described pin seamed papermaking fabric, carry out, but but also comprise the step that the non-paper of described pin seamed papermaking fabric and fibrous batts material are sewed up.

12. the method for claim 1, but wherein said application step on the paper of described pin seamed papermaking fabric, carry out, but but also comprise the step that is coated with the described non-paper of said pin seamed papermaking fabric with described first polymeric resin material.

13. the method for claim 1, but wherein said application step on the paper of described pin seamed papermaking fabric, carry out, but but also comprise the step that is coated with the described non-paper of described pin seamed papermaking fabric with the trimerization resin material.

14. the method for claim 1, but wherein said application step is carried out on the paper of described pin seamed papermaking fabric, but but also comprises than the material adhesive of the more difficult compression of sewing up of the fiber material fabric step to the described non-paper of described pin seamed papermaking fabric.

15. the method for claim 1, but wherein said pin seamed papermaking fabric includes vertical yarn, and wherein said suture ring is formed by described vertical yarn.

16. the method for claim 1 also includes the step of grinding described first polymeric resin material behind described curing schedule, so that the paper processing tape thickness of described polymer resin coating is even, and give its desirable surface characteristic.

17. the method for claim 1 after encapsulating material is applied to the step of described seam, also includes the step of topped described encapsulating material.

18. the method for claim 1, the page that also is included in the described polymer resin coating with described first polymeric resin material are handled described of band and are gone up and described seam is carried out frosted handle, so that described seam is level and smooth.

19. the method for claim 1, also comprise on two faces that at a certain distance described encapsulating material are applied to described seam with the zone on two faces of topped described seam and seam, the result is, the bending stress of handling in the band at the page of described polymer resin coating can be dispersed in than the wideer zone of described seam of eliminating described joint-cutting bending stress, equals the other parts of this band with the bending resistance in the zone that causes described seam.

20. the method for claim 1 also comprises with the step of the bonding described joint-cutting of trimerization resin material and the step of solidifying described trimerization resin material.

21. method as claimed in claim 20, the page that also is included in the described polymer resin coating with described first polymeric resin material are handled described of band and are gone up and described seam is carried out frosted handle, so that described seam is level and smooth.

22. the method for claim 1, wherein the step of topped described seam comprises:

The viscosity that comprises second polymeric resin material and blowing agent slurry is provided;

Described viscosity slurry is applied on the described seam;

Make the described blowing agent in described viscosity slurry produce gas, described whereby viscosity slurry can become foam; With

Solidify said foam.

23. method as claimed in claim 22 also comprises described viscosity slurry is applied on described the described seam of the described band with described first polymeric resin material coating.

24. method as claimed in claim 23 to the step of described seam, also comprises the step of topped described viscosity slurry at the described viscosity slurry that applies.

25. method as claimed in claim 22, wherein when compressing described seam, carry out described described blowing agent step that produces gas and the step of solidifying described foam of making, identical with thickness and/or the compression performance that causes described seam with the other parts of the page processing band of described polymer resin coating.

26. method as claimed in claim 22, wherein make described blowing agent produce gas and force described foam to enter in the described joint-cutting of described first polymeric resin material, and the step of solidifying described foam is bonded together described joint-cutting with the step of producing foam according to described viscosity slurry.

27. the method for claim 1, wherein the step of topped described seam comprises:

The liquid polymeric resin material of the prefoam that comprises second polymeric resin material is provided;

The liquid polymeric resin material of described prefoam is applied on the described seam; With

Solidify the liquid polymeric resin material of described prefoam.

28. method as claimed in claim 27, wherein, before being applied to described liquid polymeric resin material on the described seam, the degraded by the blowing agent that mixes with described second polymeric resin material and by prefoam.

29. as the method for claim 27, wherein, before being applied to described liquid polymeric resin material on the described seam, by described second polymeric resin material is mixed with low density filler by prefoam.

30. method as claimed in claim 29, wherein said low density filler comprises expanded thermoplastic microspheres.

31. the method for claim 1, wherein the step of topped described seam comprises:

The solid foam bar of second polymeric resin material is provided; With

Described solid foam bar is bonded on uncoated the described seam of described band.

32. method as claimed in claim 31 is wherein by the bonding described solid foam bar of thermal source.

33. method as claimed in claim 31 is wherein by the bonding described solid foam bar of adhesive.

34. the method for claim 1, wherein the step of topped described seam comprises:

The ribbon of fibrous batts material is provided; With

Described ribbon is bonded on uncoated the described seam of described band.

35. method as claimed in claim 34 is wherein by the bonding described ribbon of adhesive.

36. the papermaking fabric that the method for claim 1, wherein described pin can be sewed up vertically includes the multiply yarn at it; And wherein the step of topped described seam comprises:

On at least one widthwise edges of the papermaking fabric that described pin can be sewed up, cut off described multiply yarn; With

And the two ends of described multiply yarn are arranged on uncoated the described seam of described band.

37. method as claimed in claim 36 wherein is fixed on the described seam by the described two ends of spray adhesive with described multiply yarn.

38. method as claimed in claim 36, wherein said multiply yarn is a multifilament.

39. method as claimed in claim 36, wherein said multiply yarn is a staple fibre yarn.

40. method as claimed in claim 36, wherein said multiply yarn is the multifilament of distortion.

41. the page of a polymer resin coating is handled band, contains:

The papermaking fabric that pin can be sewed up, described fabric has suture ring at two widthwise edges place, and utilize fibula to pass by the staggered passage of determining of described suture ring and be connected to the endless form with paper and non-paper, thus, described fibula and suture ring have constituted the seam of described band;

It is characterized in that described suture ring forms by vertical yarn of described fabric; And

But the coating of first polymeric resin material on the described paper of described pin seamed papermaking fabric, described coating has a joint-cutting at described seam crossing; With

But the encapsulating material of topped described seam on the described non-paper of described pin seamed papermaking fabric.

42. band as claimed in claim 41, wherein said encapsulating material are the solid foam bar of second polymeric resin material, described solid foam bar is bonded on the described seam of non-paper of described band.

43. band as claimed in claim 41, wherein said encapsulating material are the ribbon of fibrous batts material, described ribbon is bonded on the described seam of non-paper of described band.

44. band as claimed in claim 41, but also comprise the interior fibrous batts material of described non-paper that sews up described pin seamed papermaking fabric.

45. band as claimed in claim 41, but on described pin seamed papermaking fabric, also contain the coating of polymeric resin material.

46. band as claimed in claim 41, but also comprise woven fabric on the non-paper that is connected to described pin seamed papermaking fabric.

47. band as claimed in claim 41, but also comprise polymeric foam plastics on the non-paper that is connected to described pin seamed papermaking fabric.

48. band as claimed in claim 41, but also comprise material than the more difficult compression of serving textile of the fibrous batts material on the non-paper that is connected to described pin seamed papermaking fabric.

49. band as claimed in claim 41, wherein said fibula are the monofilament fibula.

50. band as claimed in claim 41, wherein said fibula is the monofilament fibula of plying.

51. band as claimed in claim 41, wherein said fibula is the multifilament fibula of plying.

52. band as claimed in claim 41, wherein said fibula are the compound fibula that comprises the monofilament fibula.

53. band as claimed in claim 41, wherein said fibula are the compound fibula that comprises the plied monofilament fibula.

54. band as claimed in claim 41, wherein said fibula are the compound fibula that comprises the plied multifilament fibula.

55. band as claimed in claim 41 wherein, becomes closure state with the trimerization resin material that solidifies with described joint-cutting involution.

56. band as claimed in claim 41, but wherein said encapsulating material is for being full of the foamed plastics of second polymeric resin material of described seam from the described non-paper of described pin seamed papermaking fabric.

57. band as claimed in claim 56, wherein said foamed plastics also extends into described joint-cutting, and described joint-cutting involution is become closure state.

58. band as claimed in claim 41, but wherein said pin seamed papermaking fabric is vertically including the multiply yarn; And wherein said encapsulating material includes from the two ends of the described multiply yarn of at least one widthwise edges extension of described fabric, and the joint face of the described non-coated face of topped described band.

59. band as claimed in claim 58, the described two ends of wherein said multiply yarn are fixed on the described seam by spray adhesive.

60. band as claimed in claim 58, wherein said multiply yarn is a multifilament.

61. band as claimed in claim 58, wherein said multiply yarn is a staple fibre yarn.

62. band as claimed in claim 58, wherein said multiply yarn is the multifilament of distortion.

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