CN114450449A

CN114450449A - Machine and method for making a decorated base web

Info

Publication number: CN114450449A
Application number: CN202080067692.5A
Authority: CN
Inventors: J.莫泽
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2019-09-26
Filing date: 2020-09-24
Publication date: 2022-05-06
Also published as: WO2021058615A1; EP4034705A1; DE102019125929A1

Abstract

The invention relates to a machine (1) for producing a single-ply decor base web (2) having a forming section (4) designed as a fourdrinier wire with a circulating dewatering wire (6) and a headbox (5) for applying at least one layer of a fibrous suspension onto the dewatering wire (6), preferably with an embossing roller (7) which dips into the side of the at least one layer of the fibrous suspension facing away from the dewatering wire (6), a press section (13) and a drying section (22), wherein the at least one layer of the fibrous suspension is dewatered on the dewatering wire (6) and forms a decor base web (2) having a wire side and a top side (3) there. The machine according to the invention is characterized in that the transfer belt (10) is arranged for transferring the decorated base web (2) from the dewatering wire (6) such that the top side (3) is in direct contact with said transfer belt (10) and that said transfer belt (10) is free of press nips or dewatering elements for increasing the dry weight content of the decorated base web (2).

Description

Machine and method for making a decorated base web

The invention relates to a machine for producing a single-layer decorated base web, comprising a forming section designed as a fourdrinier wire with a circulating dewatering wire and a headbox for applying at least one layer of a fibrous suspension onto the dewatering wire, preferably with an embossing roller which dips into the side of the at least one layer of a fibrous suspension facing away from the dewatering wire, and a press section and a dryer section, wherein the at least one layer of a fibrous suspension is dewatered on the dewatering wire and forms a decorated base web with a wire side and a top side.

The decorative base web has sides which are subjected to high quality requirements in the further production process. This side forms the functional side and must be as smooth, uniform and free of web and felt marks as possible. To achieve this, a machine solution with a complex press section structure is used.

Devices of this type are known. For example, document DE102008042730a1 discloses a method and a machine for coloring decorative papers. In the method, the fibre suspension is applied to the dewatering wire of the fourdrinier wire through a headbox and is dewatered there. An embossing roll is disposed above the fourdrinier wire. The formed decorative web is discharged directly from the dewatering wire by means of a felt and led to the press section and for further dewatering through the first two press nips, wherein the first press nip is double-layered with a felt. For further dewatering of the decor web, a further, separately established press is arranged downstream, which has an upper press roll and a lower press roll forming a press nip. The press nip is laid with a felt in a single layer and arranged so that the upper press roll is in direct contact with the top side of the decor web. After the third press nip is a dryer section with a dryer cylinder and a web stabilizer.

In the known solutions, on the one hand, the paper quality is often insufficient in terms of the surface quality of the top side of the web. On the other hand, the known apparatus has a complicated press section to ensure acceptable paper quality. The known press sections are also prone to tearing, especially at higher speeds. This results in poor runnability and run-time efficiency of the decorator paper machine.

The technical problem to be solved by the invention is therefore to simplify the manufacture of the decorated base web, to improve the runnability of the web and to improve the surface quality of the top side of the decorated base web forming the functional side.

This object is achieved by the features of the two independent claims. In claim 1 a machine for producing a single-ply decor base web is specified, which has a forming section designed as a fourdrinier wire with a circulating dewatering wire and a headbox for applying at least one fibre suspension layer onto the dewatering wire and preferably with an embossing roller which dips into the side of the at least one fibre suspension layer facing away from the dewatering wire, and a press section and a dryer section, wherein the at least one fibre suspension layer is dewatered on the dewatering wire and forms a decor base web with a wire side and a top side there. The invention is characterized in that the transfer belt is arranged for receiving the decorated base web from the dewatering wire such that the top side of the decorated base web is in direct contact with the transfer belt and the transfer belt is free of press nips or dewatering elements for increasing the dry weight content of the decorated base web.

By this arrangement the top side of the decorative base web, which is the functional side, is not pressed against the clothing, whereby the surface quality of the top side is not impaired, i.e. not marked by the surface structure of the clothing.

This solution allows further processing of the decor base web without deteriorating the very good surface quality of the top side of the decor base web due to e.g. the use of embossing rolls. A very good quality of the top side, i.e. the functional side of the decorated base web, can thus be obtained or even improved. A press section of simple construction can also be used with this machine solution.

The direction of travel of the dewatering wire in the area of the forming and dewatering zone is opposite to the direction of production of the decor base web.

In an advantageous practical embodiment, the decorative base web is unloaded from the transfer belt by means of pick-up rolls arranged inside a pick-up felt and guided by the pick-up felt to the press section, which is formed by exactly three press nips. The pick-up felt thus only contacts the wire side of the decorated base web.

It is possible that all three press nips are designed as roll nips. This simplifies the structure of the press section.

In a possible embodiment, the decorative base web is guided against a pick-up felt through a first press nip of the press section.

The press section preferably comprises a central roll with a smooth surface for smoothing the decorative base web, for forming a first press nip together with the suction-press roll and for forming a second press nip together with the press roll, wherein the top side of the decorative base web is in direct contact with the smooth surface of the central roll. An additional press nip is formed between the suction press roll and the leveling press roll, wherein the leveling press roll is in direct contact with the top side of the decor base web. The top side, i.e. the functional side, of the decorative base web is thus flattened in the first and second press nips and additionally in the further press nips by means of the smooth surface of the central roll. A separate fourth press for flattening the top side can thus be dispensed with. Thereby reducing the easy tearability and improving the operability. While forming a very good functional side.

The suction-press roll has a high vacuum zone in the region of the further press nip.

The suction roll is preferably designed such that a vacuum in the range of 40kPa to 60kPa can be applied in the high vacuum zone.

It is also advantageous if the length of the high vacuum zone, measured in the direction of production, is in the range from 1.5 to 2.5 times the nip length of the further press nip.

Furthermore, the suction pressure roll may be at least partly surrounded by a first press felt designed as a pick-up felt for detaching the decorative base web from the transfer belt and being guidable through the further press nip and through the first press nip, and the press roll is at least partly surrounded by a second press felt which is guidable through the second press nip.

Thus, each of the three press nips is a single layer of lay-down felt.

In a possible practical embodiment, the flattening press roll has a roll mantle made of rubber or a polyurethane matrix with fillers or made of polyurethane with a smooth surface for flattening the top side of the decorated base web. Thereby, the leveling effect and the workability are improved.

The roller shell consisting of rubber preferably has a thickness in the range from 5mm to 20mm and a hardness between 40P & J and 220P & J.

The roller shell made of polyurethane preferably has a thickness in the region of 15mm to 25mm and a hardness of between 30P & J and 150P & J. Hardness in P & J (Pusey & Jones) is determined according to the standard ASTM D531. This measurement is commonly used in the paper industry to determine the hardness of a roll cover.

Furthermore, the flattening press roll can be equipped with a doctor blade, preferably a double doctor blade, wherein two doctor blades are arranged one behind the other. This prevents the formation of a fouling coating on the surface of the roll mantle. Furthermore, wrapping of the flattening press roll with a decorative base web is avoided.

In one possible development, the press roll is formed by a shoe press roll. By means of the extended press nip it is possible to increase dewatering and at the same time maintain or even improve the paper quality by increasing the press pressure gently.

In a possible development, the central roller is surrounded by a flat belt. The surface of the smoothing belt is very smooth to smooth the top side of the decor base web. The smooth surface of the central roller is replaced in this embodiment in the smoothing function by the surface of the smoothing belt. The smoothing belt guides the decor base web in a non-free draw until the decor base web is discharged through the drying wire of the drying section. The decorative base web is thus continuously supported. This is advantageous in higher speeds and/or decorated base webs with low strength potential. Thereby also reducing the easy tear.

It is also possible that the flattening press roll and its function are replaced by a combination of a press roll and a smooth belt wrapped around it. The smoothing belt should here be softer than the press roll and preferably made of rubber or polyurethane. The smooth belt is impermeable to water. The pressing force on the top side of the decor base web is selected such that there is no dewatering in the direction of the smoothing belt.

In practice, pivotally supported guide rolls may be arranged inside the loop formed by the transfer belt, in order to receive the decorative base web from the dewatering wire via the transfer belt or pivotally arranged for maintenance purposes. Thereby, the start-up of the decorator paper machine can also be simplified and improved.

In order to stabilize the web run of the decor base web, support elements, in particular a transfer film and/or support rolls and/or suction web stabilizers, which can be operated at a negative pressure of less than 1000Pa, in particular less than 300Pa, preferably less than 150Pa, can be arranged opposite the side of the transfer belt carrying the decor base web.

This object is achieved by a method according to claim 9. A method for producing a single-ply decor base web is proposed, using a forming section designed as a fourdrinier wire with a circulating dewatering wire and a headbox for applying at least one layer of a fibrous suspension onto the dewatering wire and preferably with embossing rollers which sink into the side of the at least one layer of a fibrous suspension facing away from the dewatering wire, and a press section and a dryer section, wherein the at least one layer of a fibrous suspension is dewatered on the dewatering wire and forms a decor base web with a wire side and a top side there. The method is characterized in that for transferring the decorative base web from the dewatering wire to the transfer belt, the top side of the decorative base web is brought into direct contact with the transfer belt and the decorative base web is not pressed or dewatered on the transfer belt. The transfer belt is, that is, not used for dewatering, but preferably only for transferring the decorative base web from the dewatering wire to the first press felt, which guides the decorative base web through the first press nip.

By this method, the top side of the decorative base web, which is the functional side, is not pressed onto the clothing, whereby the surface quality of the top side is not impaired.

This solution enables the decorative base web to be further processed without deteriorating the very good surface quality of the top side of the decorative base web, also due to the use of embossing rolls for example. A very good quality of the top side, i.e. the functional side, of the decorated base web can thus be obtained. A press section of simple construction can also be applied by this machine solution.

The direction of travel of the dewatering wire in the forming and dewatering zone is opposite to the direction of production of the decor base web.

In an advantageous practical embodiment, the decorative base web is unloaded from the transfer belt by means of pick-up rolls arranged inside the pick-up felt and guided by the pick-up felt to the press section formed by the three press nips.

The decorative base web is preferably guided through the first press nip by a pick-up felt.

The first press nip is preferably formed by a suction press roll and a central roll with a smooth surface to level the top side of the decorative base web, the second press nip is formed by a press roll and a central roll, and additionally a further press nip is formed between the suction press roll and the leveling press roll, wherein the leveling press roll is brought into direct contact with the top side of the decorative base web. The top side of the decor base web is brought into direct contact with the smooth surface of the central roll and with the smooth surface of the flattening press roll. The top side, i.e. the functional side of the decor base web, is thus smoothed with perfect effect in all three press nips by the smooth surface of the central roll. Thus, a separate set-up press for flattening the top side can be omitted. This reduces the easy-to-tear property and improves the operability.

In a possible embodiment, the suction pressure roll is at least partially surrounded by a first press felt which is designed as a pick-up felt for detaching the decorative base web from the transfer belt and guiding it through the further press nip and through the first press nip, and the press roll is at least partially surrounded by a second press felt which is guided through the second press nip.

Each of the three press nips is thus laid a felt in a single layer.

Preferably, the levelling press roll design has a roll mantle made of rubber or a polyurethane matrix with fillers or made of polyurethane with a smooth surface for levelling the top side of the decorated base web.

If the roll mantle is made of rubber, the thickness of the roll mantle is selected from the range of 5mm to 20mm, and the hardness of the roll mantle is selected from the range between 40P & J to 220P & J.

If the roll mantle is made of polyurethane, the thickness of the roll mantle is selected from the range of 15mm to 25mm, and the hardness of the roll mantle is selected from the range of 30P & J to 150P & J.

In a practical application, a pivotable guide roll may be provided within the loop formed by the transfer belt, wherein the guide roll is deflected towards the dewatering wire or away from the dewatering wire for maintenance purposes in order to receive the decorated base web from the dewatering wire via the transfer belt.

The invention also extends to embodiments which are not defined by the combination of features explicitly cited in the claims, and the features disclosed therein can therefore be combined with one another as desired, provided that they are technically sound.

Further features and advantages of the invention result from the following description of a preferred embodiment and with reference to the drawings.

In the drawings:

fig. 1 shows a simplified illustration of an embodiment of the machine according to the invention;

FIG. 2 shows a detail of FIG. 1 with a press section and a dryer section;

fig. 1 shows by way of example and in a simplified representation an embodiment of a machine 1 according to the invention for producing a single-layer decorated base web 2, having a forming section 4 designed as a fourdrinier wire, with a circulating dewatering wire 6 and a headbox 5 for applying at least one layer of a fibrous suspension onto the dewatering wire 6, and preferably with embossing rollers which are immersed on the side facing away from the dewatering wire 6, to the dewatering wire 6, and a press section 13 and a dryer section 22, wherein the at least one layer of a fibrous suspension is dewatered on the dewatering wire 6 and forms a decorated base web 2 having a wire side and a top side 3. Below the forming section 4 a transfer belt 10 for transferring the decorative base web 2 from the dewatering wire 6 is arranged in such a way that the top side 3 of the decorative base web 2 is in direct contact with the transfer belt 10 and the transfer belt 10 has no press nips or dewatering elements for increasing the dry weight content of the decorative base web 2. By this arrangement the top side 3 of the decor base web 2, which is the functional side, is not pressed against the clothing, whereby the surface quality of the top side 3 is not affected. The solution allowsAllowing further processing of the decor base web 2 without compromising the very good surface quality of the top side 3 of the decor base web 2, which is also produced by the use of, for example, embossing rolls 7. A very good quality of the top side 3, i.e. the functional side of the decor base web 2, is thus obtained or even improved. With this machine solution, it is also possible to use a simply constructed and advantageous press section 13. The fibre suspension is supplied to the wire in the form of jets by means of a headbox 5. The direction of the jet flow is in this case the direction of travel L of the dewatering wire 6 in the region of the forming and dewatering zone of the forming section 4_FAre substantially the same. In the region of the forming and dewatering space, an embossing roller 7 is arranged, which is slightly recessed into the side of the fibre suspension facing away from the dewatering wire 6. A very uniform distribution of the fibres and solids contained in the fibre suspension and a good surface characteristic in the area of the top side 3 of the resulting decor base web 2 are hereby achieved. In the area of the forming and dewatering zone dewatering elements 8 are arranged. At the end of the forming section 4, the decor base web 2 is transferred in the region of the transfer roll 9 onto a transfer belt 10. The decorated base web 2 is then passed by means of the transfer belt 10 in the running direction L of the dewatering wire 6 in the area of the forming and dewatering zone of the forming section 4_FOpposite production direction L_PTowards the press and dryer sections (13, 22). In order to stabilize the web run of the decor base web 2, a support element 12, in particular a transfer film and/or a support roll and/or a suction web stabilizer, which can be operated with a negative pressure of 300Pa, in particular 150Pa, is provided opposite the side of the transfer belt 10 carrying the decor base web 2. Inside the loop formed by the transfer belt 10 or pivotably for maintenance purposes, a pivotably mounted guide roll 11 is arranged for transferring the decor raw paper web from the dewatering wire 6 by means of the transfer belt 10. In order to receive the decor paper web 2 from the dewatering wire 6 by means of the transfer belt 10, the guide roll 11 is pivoted towards the dewatering wire 6 and receives this web. To support this reception, a conveying suction device can be provided inside the transit belt 10. In the further course, the decor base web 2 is discharged from the transfer belt 10 by means of a pick-up roll 21 arranged inside the loop of the first press felt 19 designed as a pick-up felt and likewise pivotable, and is guided by means of the pick-up felt 19 to the press section 13, which passes through exactly three press nips 17,18, 27 are formed. The pick felt 19 is thus in contact with only the wire side of the decor base web 2. The decor base web 2 is guided against a pick-up felt 19 through the first press nip 17 of the press section 13. The press section 13 comprises a central roll 14 with a smooth surface so as to form a first press nip 17 together with a suction roll 15 and a second press nip together with a press roll 16, wherein the top side 3 of the decor base web 2 is in direct contact with the smooth surface of the central roll 14. In order to increase the smoothness of the decorated base web 2, a smoothing press roll 24 is provided, which together with the suction press roll 15 forms a further press nip 27, which further press nip 27 is in the production direction L_PSeen as having been placed in the first press nip 17. The suction-pressing roll 15 has, in the region of the further press nip 27, a high-vacuum zone 26 which is designed such that a negative pressure of 40kPa to 60kPa can be applied. The length of the high vacuum zone 26 measured in the production direction lies in the range of 1.5 to 2.5 times the nip length of the further press nip 27. The high vacuum zone 26 increases the runnability of the decor base web 2 so that it runs reliably with the first press felt 19. The levelling press roll 24 is designed with a roll mantle made of rubber or polyurethane with a smooth surface for levelling the top side 3 of the decorated base web 2. The flattening press roll is in this example provided with a double doctor blade, in which two doctor edges are arranged one after the other. This prevents the formation of a fouling coating on the surface of the roll mantle. Furthermore, wrapping of the flattening press roll 24 with the decor base web 2 is avoided. All three press nips were laid with a single layer of felt. The top side 3, i.e. the functional side, of the decorative base web 2 is thus additionally flattened by the smooth surface of the central roll 14 in the first and second press nips 17, 18 and in the further press nips 27. The press section 13 has press nips 17, 18, 27, all of which are laid with a single layer of felt. Thus, a separate press for flattening the top side 3 can be dispensed with. This reduces the easy-to-tear property and improves the operability. The suction roll 15 is partly surrounded by a first press felt 19, in this example a pick-up felt, and the press roll 16 is partly surrounded by a second press felt 20. The second press nip 18 is designed as a nip press. But it may also be designed as a shoe press nip. At the second pressAfter the nip 18, the decorative base web 2 is transferred to a drying section 22 and dried there by direct contact of the top side 3 with the surface of a drying cylinder 23.

Fig. 2 shows a possible development of the machine 1 in a detail of fig. 1, which has a press section 13 and a dryer section 22. The central roll 14 is wrapped by a flat belt 28. The surface of the levelling belt 28 is designed very smooth in order to even out the top side 3 of the decor base web 2 and also to lead through the first press nip 17. At this point, the decorative base web 2 is received by the first press felt 19. The smooth surface of the central roller 14 is replaced in this embodiment in the smoothing function by the surface of the smoothing belt 28. The levelling belt 28 guides the decor base web 2 in a non-free draw until the decor base web 2 is discharged through the drying wire of the drying section. The decor base web 2 is thus continuously supported. This is advantageous at higher speeds and/or in a decorated base web 2 with low strength potential.

Corresponding elements of the embodiments in the figures are provided with the same reference numerals. Unless otherwise indicated herein and to the contrary, the functions of these are in each figure and correspond to each other. And thus duplicate description is omitted. It is further noted that different features of the embodiments shown may be interchanged and combined with one another. The invention is therefore not limited to the shown combinations of features of the embodiments shown.

List of reference numerals

1 machine

2 decorative base scroll

3 top side

4 forming part

5 head box

6 dewatering net

7 embossing roller

8 dewatering element

9 transfer roller

10 transfer belt

11 guide roller

12 support element

13 press section

14 center roll

15 suction and compression roller

16 squeezing roller

17 first press nip

18 second press nip

19 first press felt

20 second press felt

21 pick-up roller

22 drying section

23 drying drum

24 flat press roll

25 scraper

26 high vacuum zone

27 additional press nip

28 leveling belt

L_FDirection of travel of dewatering wire

L_PDirection of production

Claims

1. A machine (1) for producing a single-ply decor base web (2) having a forming section (4) designed as a fourdrinier wire, a press section (13) and a drying section (22), the forming section (4) having a circulating dewatering wire (6) and a headbox (5) for applying at least one layer of a fibrous suspension onto the dewatering wire (6) and preferably having an embossing roller (7) which is immersed on the side of the at least one layer of a fibrous suspension facing away from the dewatering wire (6), wherein the at least one layer of a fibrous suspension is dewatered on the dewatering wire (6) and forms a decor base web (2) having a wire side and a top side (3) there, characterized in that a transfer belt (10) is arranged for receiving the decor base web (2) from the dewatering wire (6) in such a way that the top side (3) is in direct contact with the transfer belt (10) and the transfer belt (10) has no press nip for increasing the press content of the decor base web (2) Or a dewatering element.

2. The machine according to claim 1, wherein,

characterized in that the decorative base web (2) is discharged from the transfer belt (10) by means of a pick-up roll (21) arranged inside a pick-up felt (19) and guided by means of the pick-up felt (19) to the press section (13), which press section (13) is formed by exactly three press nips (17, 18).

3. The machine according to claim 1 or 2,

characterized in that the press section (13) comprises a central roll (14) with a smooth surface for smoothing the decorative base web (2), for forming a first press nip (17) together with a suction press roll (15) and for forming a second press nip (18) together with a press roll (16), wherein the top side (3) of the decorative base web (2) is in direct contact with the smooth surface of the central roll (14) and a further press nip is formed between the suction press roll and a smoothing press roll (24), and the smoothing press roll (24) is in direct contact with the top side (3) of the decorative base web (2).

4. The machine according to claim 3, wherein,

characterized in that the suction press roll (15) is at least partly surrounded by a first press felt (19), which first press felt (19) is designed as a pick-up felt for discharging a decorated base web from the transfer belt (10) and is guided through a further press nip and through a first press nip, and that the press roll (16) is at least partly surrounded by a second press felt (20), which second press felt is guided through the second press nip.

5. The machine of one of claims 3 or 4,

characterized in that the levelling press roll (24) has a roll mantle made of rubber or of a polyurethane matrix or polyurethane with fillers and with a smooth surface for levelling the top side (3) of the decor base web (2).

6. The machine according to claim 6, wherein,

characterized in that the roll mantle is made of rubber, its thickness is in the range of 5mm to 20mm and its hardness is between 40P & J and 220P & J.

7. The machine according to claim 6, wherein,

characterized in that the roll mantle is made of polyurethane, its thickness is in the range of 15mm to 25mm, and its hardness is between 30P & J and 150P & J.

8. The machine according to one of claims 3 to 7,

characterized in that the flattening press roll (24) is provided with a doctor blade (25), preferably a double doctor blade.

9. A method for manufacturing a single-ply decor base web (2) with a forming section (4) designed as a fourdrinier wire, with a circulating dewatering wire (6) and a headbox (5) for applying at least one layer of a fibrous suspension onto the dewatering wire (6) and preferably with an embossing roller (7) which is immersed on the side of the at least one layer of a fibrous suspension facing away from the dewatering wire (6), a press section (13) and a drying section (22), wherein the at least one layer of a fibrous suspension is dewatered on the dewatering wire (6) and forms a decor base web (2) with a wire side and a top side (3) there, characterized in that, for transferring the decor base web (2) from the dewatering wire (6) onto a transfer belt (10), the top side (3) of the decor base web (2) is brought into direct contact with the transfer belt (10) and not for increasing the dry weight content of the decor base web (2) on the transfer belt (10) The decorative base web (2) is pressed or dewatered.

10. The method of claim 9, wherein the step of,

characterized in that the decorative base web (2) is discharged from the transfer belt (10) by means of a pick-up roll (21) arranged inside a pick-up felt (17) and guided by means of the pick-up felt (17) to a press section (13), which press section (13) is formed by exactly three press nips (17, 18).

11. A method according to claim 9 or 10, characterized in that the first press nip (17) is formed by a suction press roll (15) and a centre roll (14) with a smooth surface for smoothing the top side (3) of the decorated base web (2), and that the second press nip (18) is formed by a press roll (16) and the centre roll (14), and that a further press nip is formed between the suction press roll and a smoothing press roll (24), which smoothing press roll (24) is in direct contact with the top side of the decorated base web (2).

12. The method of claim 11, wherein the step of,

characterized in that the suction press roll (15) is at least partly surrounded by a first press felt (19), which first press felt (19) is designed as a pick-up felt for unloading the decorative base web (2) from the transfer belt (10) and is guided through a further press nip and through the first press nip, and that the press roll (16) is at least partly surrounded by a second press felt (20), which second press felt (20) is guided through the second press nip.

13. Method according to one of claims 11 or 12, characterized in that the levelling press roll (24) is designed with a roll mantle, which is made of rubber or a polyurethane matrix with fillers or polyurethane and has a smooth surface for levelling the top side of the decorated base web (2).

14. The method of claim 13, wherein the step of,

characterized in that the roll mantle is made of rubber, its thickness is in the range of 5mm to 20mm, and its hardness is between 40P & J and 220P & J.

15. The method of claim 13, wherein the step of,