CN116745085A - Method for substance utilization of polyurethane - Google Patents
Method for substance utilization of polyurethane Download PDFInfo
- Publication number
- CN116745085A CN116745085A CN202180090326.6A CN202180090326A CN116745085A CN 116745085 A CN116745085 A CN 116745085A CN 202180090326 A CN202180090326 A CN 202180090326A CN 116745085 A CN116745085 A CN 116745085A
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- China
- Prior art keywords
- polyurethane
- press
- producing
- conveyor belt
- weight
- 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.)
- Pending
Links
- 229920002635 polyurethane Polymers 0.000 title claims abstract description 83
- 239000004814 polyurethane Substances 0.000 title claims abstract description 83
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000000126 substance Substances 0.000 title claims abstract description 16
- 239000000835 fiber Substances 0.000 claims abstract description 25
- 150000001412 amines Chemical class 0.000 claims abstract description 20
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 11
- 230000003014 reinforcing effect Effects 0.000 claims description 13
- 239000004971 Cross linker Substances 0.000 claims description 9
- 239000004744 fabric Substances 0.000 claims description 8
- 238000002844 melting Methods 0.000 claims description 7
- 230000008018 melting Effects 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 6
- 150000002009 diols Chemical group 0.000 claims description 5
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 claims description 4
- 230000006835 compression Effects 0.000 claims description 4
- 238000007906 compression Methods 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 claims description 2
- 238000002679 ablation Methods 0.000 claims description 2
- 239000011324 bead Substances 0.000 claims description 2
- 238000005520 cutting process Methods 0.000 claims description 2
- 238000007872 degassing Methods 0.000 claims description 2
- 230000007717 exclusion Effects 0.000 claims description 2
- 238000001125 extrusion Methods 0.000 claims description 2
- XXMIOPMDWAUFGU-UHFFFAOYSA-N hexane-1,6-diol Chemical compound OCCCCCCO XXMIOPMDWAUFGU-UHFFFAOYSA-N 0.000 claims description 2
- 238000001746 injection moulding Methods 0.000 claims description 2
- 238000010309 melting process Methods 0.000 claims description 2
- 238000007873 sieving Methods 0.000 claims description 2
- 229920001169 thermoplastic Polymers 0.000 description 8
- 239000004416 thermosoftening plastic Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000013011 mating Effects 0.000 description 6
- 239000002131 composite material Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 239000004433 Thermoplastic polyurethane Substances 0.000 description 3
- 239000000654 additive Substances 0.000 description 3
- 150000001875 compounds Chemical group 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 229920001971 elastomer Polymers 0.000 description 3
- 239000000945 filler Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 229920005862 polyol Polymers 0.000 description 3
- 150000003077 polyols Chemical class 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 229920002803 thermoplastic polyurethane Polymers 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- -1 fibres Chemical group 0.000 description 2
- 239000012634 fragment Substances 0.000 description 2
- 239000012948 isocyanate Substances 0.000 description 2
- 150000002513 isocyanates Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000012080 ambient air Substances 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 238000010923 batch production Methods 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000012783 reinforcing fiber Substances 0.000 description 1
- 239000003206 sterilizing agent Substances 0.000 description 1
- 229920002725 thermoplastic elastomer Polymers 0.000 description 1
- 150000004072 triols Chemical class 0.000 description 1
- 238000004073 vulcanization Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/0026—Recovery of plastics or other constituents of waste material containing plastics by agglomeration or compacting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0217—Mechanical separating techniques; devices therefor
- B29B2017/022—Grippers, hooks, piercing needles, fingers, e.g. mounted on robots
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0217—Mechanical separating techniques; devices therefor
- B29B2017/0224—Screens, sieves
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29B—PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
- B29B17/02—Separating plastics from other materials
- B29B2017/0213—Specific separating techniques
- B29B2017/0255—Specific separating techniques using different melting or softening temperatures of the materials to be separated
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2075/00—Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2029/00—Belts or bands
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/32—Wheels, pinions, pulleys, castors or rollers, Rims
- B29L2031/324—Rollers or cylinders having an axial length of several times the diameter, e.g. embossing, pressing or printing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2031/00—Other particular articles
- B29L2031/709—Articles shaped in a closed loop, e.g. conveyor belts
- B29L2031/7092—Conveyor belts
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Mechanical Engineering (AREA)
- Paper (AREA)
- Processing Of Solid Wastes (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
The application relates to a method for substance utilization of polyurethane from a press jacket (6) or a press roll or a conveyor belt, in particular for machines for producing or treating fiber webs, such as paper, board or tissue machines, wherein the press jacket or the press roll or the conveyor belt comprises at least one layer (11) comprising crosslinked polyurethane, wherein the polyurethane is heated to a temperature of more than 150 ℃ and thus melted, wherein the polyurethane comprises an amine crosslinking agent. The application further relates to a press jacket (6) or a press roll or a conveyor belt, in particular for a machine for producing or treating a fiber web, such as a paper, board or tissue machine, comprising at least one layer comprising crosslinked polyurethane, wherein the polyurethane is produced according to the method according to the application.
Description
Technical Field
The application relates to a method for substance utilization of polyurethane from a press jacket or a press roll or a conveyor belt, in particular for machines for producing or treating a fiber web, such as paper, board or towel machines, wherein the press jacket or the press roll or the conveyor belt comprises at least one layer comprising crosslinked polyurethane, wherein the polyurethane is heated to a temperature of more than 150 ℃ and is thus melted.
Background
Press rolls are used in many presses and, for example, in the form of shoe rolls in shoe presses, which in turn are used in particular for dewatering a fibrous web, such as a paper web. Such shoe presses consist of shoe rolls and mating rolls, between which a nip is formed. The shoe roll consists here of a stationary, i.e. non-rotating, press element (i.e. shoe) and a flexible press jacket surrounding the shoe. Typically, a shoe is supported by a yoke carrying it and is pressed by hydraulic press elements onto a press jacket surrounding the shoe. Here, an oil film is usually established between the shoe and the press jacket for lubrication. Due to the concave design of the shoe on its side opposite the mating roll, a relatively long nip is obtained, which is about 20 times longer than the nip of a conventional press consisting of two encircling rolls. In the operation of the shoe press, the fibre web is led through the press nip together with one or two press felts and/or another conveyor belt, wherein liquid escaping from the fibre web as a result of the pressure exerted on the fibre web in the press nip, in addition to water, contains dissolved and undissolved compounds, such as fibres, fibre fragments, fillers and/or additives, which are temporarily absorbed by the press felts and depressions provided in the surface of the press jacket. After leaving the press nip, the liquid absorbed by the press jacket is thrown away from the press jacket before the press jacket re-enters the press nip. In addition, the water absorbed by the press felt is removed by the suction element after leaving the press nip. The use of such a shoe press achieves better dewatering of the fibre web than a press consisting of two rotating rolls, since the concave design of the shoe results in a relatively long press nip, whereby the subsequent thermal drying can be correspondingly shortened. In this way, particularly gentle and energy-saving dewatering of the fiber web is achieved.
The life of the press jacket and the conveyor belt is limited due to the high loads caused by water, fillers and/or additives, and the mechanical stresses caused by the press pulses and the manufacturing speed. After use, the worn press jacket or belt is typically disposed of by dumping it in a landfill or incinerating it, depending on the area.
A process for the recovery of polyurethanes is known from publication EP3744812A1, which, however, involves pyrolysis and does not take advantage of the thermoplastic properties of the polyurethanes.
The production of thermoplastic rubber-polyurethane composite structures is known from publication EP3689935A1, which, although taking advantage of the thermoplastic properties of the polyurethane composite, is not suitable for use in press jackets. Because such a composite structure is not suitable for the high mechanical and chemical loading of the press jacket and the conveyor belt. In particular, the press jacket is treated with sterilizing agents and chemical cleaners regularly in the shoe press, so that rubber compositions are not possible.
Publication EP0607735A1 describes a process for recovering polyurethane. Here, thermoplastic polyurethane waste material generated by a factory during shoe sole manufacturing is collected, cleaned and crushed to be remelted in a screw press at a temperature between 140 ℃ and 160 ℃. There is no information in this publication about the chemical composition of the polyurethane used. However, it is not desirable that such polyurethane is a polyurethane suitable for use in a press jacket or a press roll or a conveyor belt, in particular for a machine for producing or treating a fibrous web, such as a paper, board or towel machine.
Publication DE102013200482A1 describes a method for processing a fiber composite component. However, the matrix material is not reused here primarily, but rather high-quality reinforcing fibers in the matrix material, for example carbon fibers in the automobile industry components, are recovered. It is only mentioned that the aqueous phase containing the decomposition products of the plastics can be processed, if necessary, to form new chemical raw materials. Thus, the plastic matrix material, for example polyurethane, should first be decomposed into its individual components.
Publication WO2016055414A1 describes a mat or belt for use in track construction for rail vehicles, road construction or as a conveyor belt for conveying minerals in quarries, gravel engineering or mine construction. The mat or belt is produced without vulcanization during the dispersion process and consists of at least two dispersion layers of thermoplastic elastomer compounds in the form of a rubber powder modified polymer alloy comprising rubber powder and a primary thermoplastic and at least one fabric layer.
A method of the type described at the beginning for the utilization of polyurethane materials is described in the patent application published after 2021, 4 and 21. Thermoplastic polyurethane, such as polyurethane for toothed belts, is recovered by remelting at a temperature between 50 ℃ and 300 ℃. However, this publication teaches that the crosslinking agent of the polyurethane to be recovered is only allowed to be formed from polyols, such as diols or triols, but not from amines.
In practice, press jackets, in particular shoe press jackets, are used nowadays in machines for producing or treating fibre webs, such as paper, board or tissue machines, which press jackets contain polyurethane whose cross-linking agent is partly composed of amines. In the case of such press jackets, it has been assumed so far that the amine-crosslinked polyurethane cannot be remelted here, since it does not have the thermoplastic properties required for this purpose.
Disclosure of Invention
The problem underlying the application is to improve the CO with respect to press jackets (in particular shoe press jackets), press rolls (in particular covers thereof) or conveyor belts used in machines for producing or treating fiber webs 2 Balance.
This technical problem is solved by a method and an apparatus according to the independent claims. The dependent claims relate to advantageous embodiments of the application.
According to a first aspect of the application, the technical problem is therefore solved by a method of the type described in the opening paragraph, wherein the polyurethane comprises an amine crosslinker.
It will be appreciated that, contrary to the long-standing prejudice in the technical field, it is in fact possible to melt and in this way relatively simply recycle the polyurethane coming from the press jacket, the press roll or the conveyor belt, which is encased in the crosslinking agentIncluding amines, such as diamines. In view of the relatively short duration of use, especially in the case of shoe press belts, combustion of large amounts of polyurethane can be avoided. This is true for CO in the production of fibrous webs, such as paper webs 2 Balance has a positive effect. In fact, although polyurethane contains amine in the crosslinking agent, it is not foreseeable that polyurethane has sufficient thermoplastic properties to be reused in a sufficiently high quality manner, in particular for manufacturing new press jackets or new press rolls or press roll covers or new conveyor belts for machines for producing or treating fiber webs.
However, here, the amine component in the crosslinking agent of the polyurethane to be recovered should not be so great that the polyurethane does not lose its thermoplastic properties. The proportion of amine crosslinker is preferably at least 2% by weight and/or at most 15% by weight, more preferably at least 3% by weight and/or at most 10% by weight, still more preferably at least 4% by weight and/or at most 9% by weight. Such amine ratios lead to particularly good results in practice.
Weight percent relates here to the total weight of the crosslinking agent. The crosslinking agent is used to crosslink the polyol and isocyanate with each other. In the first production of such press jackets or rolls, or press roll covers or belts, polyurethane is often used as so-called "Cast polyurethane". That is, the individual components of the polyurethane, such as the polyol, isocyanate and crosslinker, contact each other and react with each other only when the final product is produced. However, the same polyurethane can then be used in recycling as a so-called "Mold polyurethane". That is, the polyurethane may be crushed and remelted at a corresponding temperature. The polyurethane retains its physical properties to a sufficient extent to be able to be reused in the press jacket, press roll or press roll cover, or conveyor belt of the machine used to produce the fiber web. But may of course be used for other products if desired.
In order to provide the thermoplastic properties of the polyurethane, at least a part of the residual crosslinking agent, preferably all of the residual crosslinking agent, consists of a short-chain diol group, in particular of 1, 2-ethanediol and/or 1, 4-butanediol and/or 1, 6-hexanediol.
Preferably, the melting temperature of the polyurethane is between 150 ℃ and 260 ℃. This can be achieved by targeted mixing of the amine and the short-chain diol, in particular the diol according to formula (I).
HO-(CH 2 ) x -OH(I)
Wherein in formula (I), x is an integer between 2 and 14, preferably between 2 and 6.
In order to support the recovery process, it is advantageous for the melting of the polyurethane to be effected at a pressure of greater than or equal to 10 barA. The unit "barA" here stands for "absolute bar", i.e. irrespective of the ambient air pressure.
In order to impart the necessary stability to the product, the press jacket or press roll or belt advantageously also comprises a reinforcing structure, such as a support fabric, which is preferably completely surrounded by polyurethane. For example, the laying of a scrim or knitted fabric is also contemplated as a suitable reinforcing structure.
An embodiment of the method according to the application provides that the polyurethane layer, whose polyurethane is melted, does not have a reinforcing structure. In other words, only polyurethane that is not embedded in the reinforcing structure is recycled. For example, if the reinforcing structure is only provided in the middle layer of the shoe press jacket, only the polyurethane of the radially inner and/or outer layer may be separated and remelted. This saves the effort of separating the infusible reinforcing structure from the polyurethane directly surrounding the reinforcing structure.
However, it can be provided that non-meltable components, in particular dirt or parts of the reinforcing structure, for example parts of the support fabric, are removed from the melted polyurethane, in particular by sieving, raking, decanting or skimming.
It is irrelevant here whether the process for substance utilization of the polyurethane is carried out continuously or in closed process steps (so-called batch processes). If a continuous process is present, it is also advantageous to continuously carry away the non-meltable components and thus to separate the melted polyurethane into different masses.
Alternatively or additionally, non-meltable components, in particular dirt or parts of the reinforcing structure, for example parts of the support fabric, can also be mechanically separated from the polyurethane layer prior to the melting process, in particular by cutting ablation.
The recovery of polyurethane is particularly good if the melting of polyurethane takes place in a closed conveying device, in particular in a screw press, preferably with exclusion of oxygen. The conveying device may comprise a conveying zone, a compression zone, a homogenization zone, a heating zone and/or one or more deaeration devices.
The conveying device may be selected such that an operating pressure of more than 10barA and a melting temperature of the thermoplastic polyurethane of more than 150 ℃ can be achieved. The deaeration device can ensure that oxygen can be removed, in particular by means of a vacuum in the connection. In addition, water vapor generated from the moisture content of the pulverized polyurethane or from hygroscopic bound water can also be removed by the deaerator.
After remelting of the polyurethane to be recovered, bead particles can be formed from the melted polyurethane, suitable for use in further process steps, such as injection molding and/or extrusion processes, for producing new products, in particular for producing press jackets or press rolls or conveyor belts, in particular for machines for producing or treating fiber webs, such as paper, board or tissue machines.
Another aspect of the application relates to a press jacket or press roll cover or conveyor belt, in particular for a machine for producing or treating a fibrous web, such as a paper, board or towel machine, comprising at least one layer comprising crosslinked polyurethane, wherein the polyurethane is produced according to the method for substance utilization of polyurethane described previously.
Drawings
The application is described below with reference to the drawings. In the drawings, in detail:
FIG. 1 shows a schematic view of a shoe press with a press jacket according to an embodiment of the application, and
fig. 2 shows a schematic diagram of a method for substance utilization of polyurethane according to an embodiment of the application.
Detailed Description
In fig. 1 a shoe press 1 is shown in schematic cross section, comprising a shoe roll 2 and a mating roll 3. The mating roll 3 consists of a rotating cylindrical design roll, while the shoe roll 2 consists of a shoe 4, a vertical yoke 5 supporting the shoe and a press jacket 6. The shoe 4 is supported here by a yoke 5 and is pressed against a press jacket 6 surrounding the shoe by means of a hydraulic press element (not shown). Due to the concave design of the shoe 4 on its side opposite the mating roll 3, a relatively long press nip 7 is obtained.
The shoe press 1 is suitable, inter alia, for dewatering a fibrous web 8, such as a paper web. In the operation of the shoe press 1, the fiber web 8 is guided through the press nip 7 by means of one or two press felts 9, wherein liquid escaping from the fiber web 8 as a result of the pressure applied to the fiber web 8 in the press nip 7, in addition to water, contains dissolved and undissolved compounds, such as fibers, fiber fragments, fillers and/or additives, which are temporarily absorbed by the press felts 9 and depressions, such as grooves or blind holes (not shown), provided in the press jacket surface. After leaving the press nip 7, the liquid absorbed by the press jacket 6 is thrown away from the press jacket 6 before the press jacket 6 re-enters the press nip 7. In addition, the water absorbed by the press felt 9 is removed by the suction element after leaving the press nip 7.
Due to the concave design of the shoe 4 on its side opposite the counter roll 3, the press nip 7 is relatively long, and a significantly better dewatering of the fibre web 8 is achieved with this shoe press 1 than with a press consisting of two rotating rolls, whereby the subsequent thermal drying can be correspondingly shortened. In this way, particularly gentle dewatering of the fiber web 8 is achieved.
In fig. 2, an apparatus 10 for a method of substance utilization of a press jacket 6 is shown. The polyurethane layer 11 is first mechanically removed from the press jacket 6 and then melted and processed into granules in the conveyor 12. In the exemplary illustration, the conveying device 12 is designed as a screw press 13. The conveyor 12 has one or more deaeration devices 14, a conveyor zone 15, a compression zone 16, a homogenizing zone 17, and one or more heating elements 18 that melt the portion of the polyurethane layer 11 in a heating zone 19. After optional cleaning for removing non-meltable residues 21, polyurethane particles 20 usable for the substance utilization 10 may be produced subsequently by cooling and depressurizing.
It should also be noted in general that when the present application refers to an "amine" crosslinker or an "amine" component, this is understood to be synonymous with an "amine" crosslinker or an "amine" component. Both terms "amine" and "amine" are known in the art.
List of reference numerals
1 shoe press
2-shoe press roll
3 mating roll
4 boots
5 vertical yoke
6 squeeze sleeve
7 press nip
8 fiber web
9 press felt
10 device for substance utilization of polyurethane
11. Polyurethane layer
12. Conveying device
13. Screw squeezer
14. Degassing device
15. Delivery area
16. Compression region
17. Homogenizing zone
18. Heating element
19. Heating zone
20. Polyurethane particles
21. Non-meltable residues
Claims (15)
1. Method for substance utilization of polyurethane from a press jacket (6) or a press roll or a conveyor belt, in particular for a machine for producing or processing a fiber web, such as a paper, board or tissue machine, wherein the press jacket or the press roll or the conveyor belt comprises at least one layer (11) comprising crosslinked polyurethane, wherein the polyurethane is heated to a temperature of more than 150 ℃ and thereby melted,
characterized in that the polyurethane comprises an amine crosslinker.
2. The method according to claim 1,
characterized in that the proportion of amine crosslinker is at least 2% by weight and/or at most 15% by weight.
3. The method according to claim 1 or 2,
characterized in that the proportion of amine crosslinker is at least 3% by weight and/or at most 10% by weight.
4. The method according to any of the preceding claims,
characterized in that the proportion of amine crosslinker is at least 4% by weight and/or at most 9% by weight.
5. The method according to any of the preceding claims,
characterized in that at least a part of the residual crosslinking agent, preferably all of the residual crosslinking agent, consists of a short-chain diol group, in particular of 1, 2-ethanediol and/or 1, 4-butanediol and/or 1, 6-hexanediol.
6. The method according to any of the preceding claims,
characterized in that the melting temperature of the polyurethane is between 150 ℃ and 260 ℃.
7. The method according to any of the preceding claims,
characterized in that the melting of the polyurethane is effected at a pressure greater than or equal to 10 barA.
8. The method according to any of the preceding claims,
characterized in that the press jacket or the press roll or the conveyor belt further comprises a reinforcing structure, such as a support fabric, which is preferably completely surrounded by polyurethane.
9. The method according to claim 8, wherein the method comprises,
it is characterized in that the method comprises the steps of,
the polyurethane layer in which the polyurethane is melted does not have a reinforcing structure.
10. The method according to any of the preceding claims,
characterized in that non-meltable components, in particular dirt or parts of the reinforcing structure, for example parts of the support fabric, are removed from the melted polyurethane, in particular by sieving, raking, decanting or skimming.
11. The method according to any of the preceding claims,
characterized in that the non-meltable components, in particular dirt or parts of the reinforcing structure, for example parts of the support fabric, are mechanically separated from the polyurethane layer (11) prior to the melting process, in particular by cutting ablation.
12. The method according to any of the preceding claims,
characterized in that the melting of the polyurethane takes place in a closed conveying device (12), in particular in a screw press (13), preferably with the exclusion of oxygen.
13. The method according to claim 12,
characterized in that the conveying means (12) comprise a conveying zone (15), a compression zone (16), a homogenizing zone (17), a heating zone (19) and/or one or more degassing means (14).
14. The method according to any of the preceding claims,
characterized in that bead particles (20) are formed from molten polyurethane, suitable for use in further process steps, such as injection molding and/or extrusion processes, for producing new products, in particular for producing press jackets (6) or press rolls or conveyor belts, in particular for machines for producing or treating fiber webs, such as paper, board or tissue machines.
15. Press jacket (6) or press roll or conveyor belt, in particular for a machine for producing or treating a fibrous web, such as a paper, board or tissue machine, comprising at least one layer comprising crosslinked polyurethane, wherein the polyurethane is produced according to the method for substance utilization of polyurethane as claimed in any of the preceding claims.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102021100483.7A DE102021100483A1 (en) | 2021-01-13 | 2021-01-13 | Polyurethane recycling |
| DE102021100483.7 | 2021-01-13 | ||
| PCT/EP2021/086731 WO2022152514A1 (en) | 2021-01-13 | 2021-12-20 | Process for physical utilization of a polyurethane |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116745085A true CN116745085A (en) | 2023-09-12 |
Family
ID=79602251
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202180090326.6A Pending CN116745085A (en) | 2021-01-13 | 2021-12-20 | Method for substance utilization of polyurethane |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP4277774A1 (en) |
| JP (1) | JP2024504106A (en) |
| CN (1) | CN116745085A (en) |
| DE (1) | DE102021100483A1 (en) |
| WO (1) | WO2022152514A1 (en) |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69324788D1 (en) | 1993-01-18 | 1999-06-10 | Microlite Sl | Process for the recovery of polyurethane |
| FI121015B (en) * | 2007-07-05 | 2010-06-15 | Tamfelt Pmc Oy | The shoe press belt |
| JP4616408B1 (en) * | 2010-02-19 | 2011-01-19 | イチカワ株式会社 | Process belt for papermaking |
| DE102011079894A1 (en) * | 2011-07-27 | 2013-01-31 | Voith Patent Gmbh | Press cover for a shoe press or conveyor belt based on cross-linked polyurethane formed from MDI polycarbonate prepolymer |
| US20150308044A1 (en) * | 2012-12-07 | 2015-10-29 | Voith Patent Gmbh | Press jacket for press roller |
| DE102013200482A1 (en) | 2013-01-15 | 2014-07-17 | Siemens Aktiengesellschaft | Process for recovering reinforcing fibers from fiber-reinforced plastics |
| CH710216A2 (en) | 2014-10-07 | 2016-04-15 | Kölbl Eng Und Consulting Gmbh | Mat or belt. |
| DE102017101562B4 (en) * | 2017-01-26 | 2022-03-03 | Forbo Siegling Gmbh | Process for manufacturing and/or recycling a conveyor belt and conveyor belt |
| DE102018122782A1 (en) * | 2018-09-18 | 2020-03-19 | Voith Patent Gmbh | Press jacket, its use as well as press roll and shoe press |
| EP3689935A1 (en) | 2019-01-30 | 2020-08-05 | Politechnika Gdanska | Thermoplastic polyurethane-rubber composite and method for obtaining thermoplastic polyurethane-rubber composite |
| EP3744812B1 (en) | 2019-05-27 | 2022-01-12 | Covestro Deutschland AG | Method for the recycling of polyurethane material waste for the production of chemical raw materials for the production of isocyanates and polyurethanes |
| EP3808532A1 (en) | 2019-10-15 | 2021-04-21 | LANXESS Corporation | Recycling of cast polyurethane |
-
2021
- 2021-01-13 DE DE102021100483.7A patent/DE102021100483A1/en active Pending
- 2021-12-20 JP JP2023542558A patent/JP2024504106A/en active Pending
- 2021-12-20 EP EP21843623.6A patent/EP4277774A1/en active Pending
- 2021-12-20 WO PCT/EP2021/086731 patent/WO2022152514A1/en active Application Filing
- 2021-12-20 CN CN202180090326.6A patent/CN116745085A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP4277774A1 (en) | 2023-11-22 |
| DE102021100483A1 (en) | 2022-07-14 |
| JP2024504106A (en) | 2024-01-30 |
| WO2022152514A1 (en) | 2022-07-21 |
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