DE4013715A1 - Reducing deposits on walls of vessels for polymer emulsions - by maintaining specific voltage between an anode in emulsion and vessel wall or stirrer as cathode - Google Patents
Reducing deposits on walls of vessels for polymer emulsions - by maintaining specific voltage between an anode in emulsion and vessel wall or stirrer as cathodeInfo
- Publication number
- DE4013715A1 DE4013715A1 DE4013715A DE4013715A DE4013715A1 DE 4013715 A1 DE4013715 A1 DE 4013715A1 DE 4013715 A DE4013715 A DE 4013715A DE 4013715 A DE4013715 A DE 4013715A DE 4013715 A1 DE4013715 A1 DE 4013715A1
- Authority
- DE
- Germany
- Prior art keywords
- vessels
- cathode
- anode
- stirrer
- walls
- 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.)
- Withdrawn
Links
- 229920000642 polymer Polymers 0.000 title claims abstract description 16
- 239000000839 emulsion Substances 0.000 title description 3
- 238000000034 method Methods 0.000 claims abstract description 5
- 229920000126 latex Polymers 0.000 abstract description 7
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 238000000576 coating method Methods 0.000 abstract 1
- 239000006185 dispersion Substances 0.000 description 5
- 229920001971 elastomer Polymers 0.000 description 5
- 238000007720 emulsion polymerization reaction Methods 0.000 description 5
- 238000006116 polymerization reaction Methods 0.000 description 5
- 239000005060 rubber Substances 0.000 description 5
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000003995 emulsifying agent Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 238000010559 graft polymerization reaction Methods 0.000 description 1
- 230000000415 inactivating effect Effects 0.000 description 1
- 239000004816 latex Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229920002587 poly(1,3-butadiene) polymer Polymers 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 229920002285 poly(styrene-co-acrylonitrile) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 239000003505 polymerization initiator Substances 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/002—Scale prevention in a polymerisation reactor or its auxiliary parts
Abstract
Description
Chemiewerkstoffe - Kautschuke und Kunststoffe - werden häufig durch Emulsionspolymerisation hergestellt. Bei diesen Polymerisationsverfahren emulgiert man das Mono mer oder die Monomeren in Wasser mit Hilfe eines Emul gators, fügt einen Polymerisationsinitiator zu und er hält nach der Polymerisation als primäres Produkt eine Dispersion des Chemiewerkstoffs in Wasser. Aus dieser Dispersion wird das Polymerisat - der Chemiewerkstoff in fester Form abgetrennt durch Brechen der Dispersion (z. B. durch Inaktivierung des Emulgators mit Hilfe von Elektrolyten) und mechanische Abtrennung des Koagulats. Die Dispersion des Polymerisats nennt man auch Latex. Durch Emulsionspolymerisation stellt man u. a. in tech nischem Maßstab Butadienpolymerisate (Polybutadien, Styrol-Butadien-Copolymerisat), also Kautschuke, und Styrolpolymerisate (Polystyrol, Styrol-Acrylnitril-Co polymerisat) sowie Acrylatpolymerisate (Polymethylmeth acrylat), also thermoplastische Kunststoffe her. Eine Variante ist die Pfropfpolymerisation, bei der man bei spielsweise erst einen Kautschuk herstellt, in die Dis persion des Kautschuks weitere Monomere emulgiert und ein zweites Mal polymerisiert. Auf diese Weise werden beispielsweise ABS-Kunststoffe erzeugt, also Produkte aus Teilchen mit einem Kautschukkern, der von einem Kunststoff umhüllt ist.Chemical materials - rubbers and plastics - are often made by emulsion polymerization. At this polymerization process emulsifies the mono mer or the monomers in water with the help of an emul gators, adds a polymerization initiator and he holds one as the primary product after polymerization Dispersion of the chemical material in water. From this Dispersion becomes the polymer - the chemical material separated in solid form by breaking the dispersion (e.g. by inactivating the emulsifier using Electrolytes) and mechanical separation of the coagulum. The dispersion of the polymer is also called latex. By emulsion polymerization u. a. in tech butadiene polymers (polybutadiene, Styrene-butadiene copolymer), ie rubbers, and Styrene polymers (polystyrene, styrene-acrylonitrile co polymer) and acrylate polymers (polymethyl meth acrylate), i.e. thermoplastics. A Variant is the graft polymerization, in which one at for example, first produces a rubber in the dis persion of the rubber emulsifies further monomers and polymerized a second time. That way For example, ABS plastics are produced, i.e. products from particles with a rubber core that is made by a Plastic is encased.
Bei der Emulsionspolymerisation bildet sich an den Reak torwänden ein Belag aus dem Polymerisat aus, ebenso bil den sich Beläge in den Rohrleitungen und in den Lager tanks beim Lagern solcher Latices. Dies kommt daher, daß die Latices nicht völlig stabil sind, es wird vielmehr ein kleiner Teil des gebildeten Polymerisats (bis zu etwa 5 Gew.-%) spontan abgeschieden. Diese Abscheidungen sammeln sich auf den Gefäßwänden an. Auf diese Weise entsteht nicht nur ein Verlust an Polymerisat, sondern die Geräte müssen in regelmäßigen Abständen gereinigt werden. Besonders ist wichtig, daß die Reaktoren frei von Wandbelägen sind, weil diese den Wärmeübergang be hindern und die Kontrolle der exothermen Polymerisati onsreaktion erschweren oder sogar unmöglich machen. Daß Beläge dieser Art Rohrleitungen verstopfen können und Lagerbehälter auf Dauer unbrauchbar machen können, ist offensichtlich. Zur Entfernung der Wandbeläge in Reak toren muß die Polymerisation unterbrochen werden, was natürlich Stillstand des Betriebes zur Folge hat. Die Reinigung der Gefäße ist meist nur mit Hochdruckwasser reinigungsgeräten möglich, also durch ein langwieriges und unangenehmes Verfahren.The emulsion forms on the reak gate walls a covering from the polymer, also bil the deposits in the pipes and in the bearings tanks when storing such latices. This is because the latices are not completely stable, rather it will a small part of the polymer formed (up to about 5% by weight) deposited spontaneously. These deposits accumulate on the vessel walls. In this way there is not only a loss of polymer, but the devices must be cleaned at regular intervals will. It is particularly important that the reactors are clear of wall coverings because they are the heat transfer prevent and control the exothermic polymer make the reaction difficult or even impossible. That Coverings of this type can clog pipelines and Can make storage containers unusable in the long run obviously. To remove the wall coverings in reak The polymerization must be interrupted, which naturally results in a standstill of the company. The Cleaning the vessels is usually only with high pressure water cleaning devices possible, so through a tedious and uncomfortable procedure.
Es besteht daher das Bedürfnis, die Bildung von Wandbe lägen aus Polymerisat bei der Emulsionspolymerisation oder beim Transport und der Lagerung von Polymerlatices zu vermeiden, jedenfalls sie zu verringern. Man hat dies versucht durch Verwendung besonders glatter Wandmateri alien oder durch die kathodische Erzeugung von Wasser stoff an den Gefäßwandungen (DE-AS 23 22 405, DE-OS 23 50 720). Die bisher verwendeten Methoden sind nicht sehr wirkungsvoll und erfordern einen erheblichen Auf wand.There is therefore a need to form Wandbe would be made of polymer during emulsion polymerization or during the transport and storage of polymer latices to avoid, at least to reduce them. You have this tried by using particularly smooth wall material alien or by the cathodic production of water fabric on the vessel walls (DE-AS 23 22 405, DE-OS 23 50 720). The methods used so far are not very effective and require a significant increase wall.
Gegenstand dieser Erfindung ist eine Methode zur Ver hinderung oder Reduzierung von Wandbelägen in Gefäßen für Polymerlatices, z. B. Reaktoren für die Emulsions polymerisation und Rohrleitungen und Lagerbehältern für Polymerlatices, die dadurch gekennzeichnet ist, daß man zwischen einer oder mehreren im Inneren des Gefäßes an geordneten Elektrode als Anode und der Gefäßwand und/oder einem eventuellen vorhandenen Rührer als Kathode eine elektrische Spannung von 50 bis 500 mV bei einer Stromdichte von 0,5 bis 100 Mikroampere/m2 aufrechter hält.The present invention relates to a method for preventing or reducing wall coverings in vessels for polymer latices, e.g. B. reactors for the emulsion polymerization and pipelines and storage containers for polymer latices, which is characterized in that an electrical voltage of between one or more inside the vessel on an ordered electrode as anode and the vessel wall and / or any existing stirrer as cathode Maintains 50 to 500 mV at a current density of 0.5 to 100 microamps / m 2 .
Durch die geringe elektrische Spannung wird ohne merk lichen Stromfluß und damit ohne elektrolytische Spaltung die Bildung von Wandbelägen verhindert oder doch stark vermindert.Due to the low electrical voltage is not noticeable Lichen current flow and thus without electrolytic cleavage the formation of wall coverings prevented or at least strong reduced.
In einem V2A-Behälter von 5 l lnhalt wurde ein Copoly merisat aus 72 Gew.-% Styrol und 28 Gew.-% Acrylnitril durch Emulsionspolymerisation hergestellt. Zwischen Be hälterwand und einer in die Emulsion eintauchenden Elek trode wurde eine elektrische Spannung von 100 mV so angelegt, daß der Behälter als Kathode, die eintauchende Elektrode als Anode geschaltet war. In diesem Behälter wurden ohne Zwischenreinigung 10 Polymerisationsansätze durchgeführt. Am Ende des zehnten Ansatzes hatte sich ein Wandbelag gebildet, dessen Menge 0,32 Gew.-% des ge samten hergestellten Polymerisats ausmacht. Während der Polymerisationszeit floß zwischen der Anode und dem Behälter ein konstanter Strom von 0,2 Mikroampere.A copoly was placed in a 5 liter V2A container merisat from 72 wt .-% styrene and 28 wt .-% acrylonitrile made by emulsion polymerization. Between Be wall of the container and an elec trode became an electrical voltage of 100 mV so created that the container as the cathode, the immersing Electrode was connected as an anode. In this container were 10 polymerization batches without intermediate cleaning carried out. At the end of the tenth approach it had formed a wall covering, the amount of 0.32 wt .-% of the ge makes up all of the polymer produced. During the Polymerization time flowed between the anode and the Container has a constant current of 0.2 microamps.
Der Versuch wurde wiederholt aber keine Spannung an die Anode angelegt. Es bildete sich ein Wandbelag von insge samt 0,77 Gew.-% des hergestellten Polymerisats.The attempt was repeated but no tension on the Anode applied. A total wall covering was formed together with 0.77% by weight of the polymer produced.
Bei angelegter Spannung ist somit die Bildung des Wand belages auf weniger als die Hälfte zurückgegangen.When the voltage is applied, the wall is formed to less than half.
Claims (1)
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4013715A DE4013715A1 (en) | 1990-04-28 | 1990-04-28 | Reducing deposits on walls of vessels for polymer emulsions - by maintaining specific voltage between an anode in emulsion and vessel wall or stirrer as cathode |
GB9106589A GB2243613B (en) | 1990-04-28 | 1991-03-28 | Reducing wall coatings in vessels for polymer emulsions |
ITRM910256A IT1244509B (en) | 1990-04-28 | 1991-04-15 | REDUCTION OF THE COATING LAYER IN THE WALLS OF CONTAINERS FOR EMULSIONS OF POLYMERIZED COMPOUNDS. |
JP3117822A JPH04227703A (en) | 1990-04-28 | 1991-04-23 | Method for reducing the formation of film on the wall of polymer emulsion container |
FR9105213A FR2661415B1 (en) | 1990-04-28 | 1991-04-26 | PROCESS FOR PREVENTING DEPOSITS OF POLYMERS IN CONTAINERS. |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4013715A DE4013715A1 (en) | 1990-04-28 | 1990-04-28 | Reducing deposits on walls of vessels for polymer emulsions - by maintaining specific voltage between an anode in emulsion and vessel wall or stirrer as cathode |
Publications (1)
Publication Number | Publication Date |
---|---|
DE4013715A1 true DE4013715A1 (en) | 1991-10-31 |
Family
ID=6405349
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE4013715A Withdrawn DE4013715A1 (en) | 1990-04-28 | 1990-04-28 | Reducing deposits on walls of vessels for polymer emulsions - by maintaining specific voltage between an anode in emulsion and vessel wall or stirrer as cathode |
Country Status (5)
Country | Link |
---|---|
JP (1) | JPH04227703A (en) |
DE (1) | DE4013715A1 (en) |
FR (1) | FR2661415B1 (en) |
GB (1) | GB2243613B (en) |
IT (1) | IT1244509B (en) |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
ES425761A1 (en) * | 1973-05-04 | 1977-05-16 | Hoechst Ag | Electrolytic process for preventing deposit formation on metallic surfaces |
DE2350720C3 (en) * | 1973-10-10 | 1979-11-08 | Hoechst Ag, 6000 Frankfurt | Polymerisation process |
DE2636653A1 (en) * | 1975-08-26 | 1977-03-10 | Hoechst Ag | METHOD AND DEVICE FOR THE POLYMERIZATION OF ALPHA-AETHYLENIC UNSATURIZED MONOMERS IN AQUATIC MEDIA |
-
1990
- 1990-04-28 DE DE4013715A patent/DE4013715A1/en not_active Withdrawn
-
1991
- 1991-03-28 GB GB9106589A patent/GB2243613B/en not_active Expired - Fee Related
- 1991-04-15 IT ITRM910256A patent/IT1244509B/en active IP Right Grant
- 1991-04-23 JP JP3117822A patent/JPH04227703A/en active Pending
- 1991-04-26 FR FR9105213A patent/FR2661415B1/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
GB2243613A (en) | 1991-11-06 |
ITRM910256A0 (en) | 1991-04-15 |
GB2243613B (en) | 1993-09-15 |
JPH04227703A (en) | 1992-08-17 |
ITRM910256A1 (en) | 1992-10-15 |
FR2661415A1 (en) | 1991-10-31 |
IT1244509B (en) | 1994-07-15 |
FR2661415B1 (en) | 1994-06-03 |
GB9106589D0 (en) | 1991-05-15 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
8110 | Request for examination paragraph 44 | ||
8130 | Withdrawal |