DE102008049742A1 - Promote root growth of plants by superabsorbents - Google Patents

Abstract

The present invention relates to the use of superabsorbents for promoting the root growth of plants and a method for promoting the root growth of plants in superabsorbent rearing medium.

Description

The The present invention relates to the field of cultivation of Plants, in particular under arid, semi-arid or other low water conditions.

• – Es stehen mehr Nährstoffe zur Verfügung
• – Es kann mehr Wasser aufgenommen werden
• – Die Chancen, eine Symbiose mit Mykorrhizapilzen aufzubauen wird verbessert.

In plants, it is advantageous in most cultivation conditions to achieve the fastest possible root growth. This among other things for the following reasons:
On the one hand, a larger floor space is opened up. This results in the following advantages for the plant:

• - There are more nutrients available
• - More water can be absorbed
• - The chances to build a symbiosis with mycorrhizal fungi will be improved.

To the others improve the mechanical anchoring of the plant in the soil.

It have been known for a long time, the root growth of Encourage plants. These are either plant hormones or synthetically manufactured chemicals, the structural similarities to have plant hormones. Due to the high cost and the with these funds necessary laborious application play these, however - apart from the rooting of Cuttings - currently in the commercial garden practically no role.

It thus sets itself the task of creating a possibility In the cultivation of plants increased root growth achieve.

These The object is achieved by a use according to claim 1 and a method solved according to claim 4. Accordingly, becomes the use of superabsorbents to promote root growth proposed by plants, or a method of promotion the rooting of plants, which in a rearing medium be reared, characterized in that the rearing medium a superabsorbent is added and / or the growth medium Superabsorber includes.

According to advantageous and to that extent preferred embodiment of the present use the superabsorbent is added to or included in a growing medium the culture medium the superabsorber.

Of the Term "superabsorber" as used herein In particular, this invention means or comprises, in particular, water-containing, but water-insoluble polymers, their molecules chemically, z. By covalent or ionic bonds, or physically, z. B. by looping the polymer chains, to a three-dimensional Network are linked and which are capable at Add water or aqueous solutions Increase volume increase.

Of the Expression "promotion of root growth" and / or includes, in particular, that the average dry matter of roots versus a control of ≥ 10%, preferably ≥ 20%, more preferably ≥ 30%, and on most preferably ≥ 50% is increased. In many However, applications of the present invention are even still one increased dry matter has been found.

Of the Includes expression "breeding medium" and / or In the simplest case, it covers the soil in which the respective plants but is not limited to this.

The Rearing medium can also z. As a hydroponic or soil-free Be growing medium.

Prefers As a breeding medium are mixtures of sand, silt and clay in the fine soil with different soil skeleton shares on the total soil.

Of the Includes and / or comprises the term "plants" in particular, and insofar also preferred, all shoot plants, continue in particular and insofar preferred also all useful and ornamental plants, Cereals, grasses and trees.

preferred Sprout plants are from the classes of Pinopsida, Dicotyledoneae and monocotyledoneae. This concerns especially trees from the class of Pinopsida, subclass Coniferae; trees and ornamental plants of the genus Dicotyledoneae, subclasses Hamamelidae, Rosidae, Dilleniidae, Lamiidae, ornamental plants and cereals from the class of Monocotyledonae, subclass Liliidae and Arecidae.

Preferred grasses are in particular the species and varieties:
Lolium perenne
Poa pratensis L. Varieties 'Award,''Liberator,''ChicagoII,''Rambo,''NuBlue'
Poa annua var. Reptans Hausskn.
Festuca arundinacea L. 'Barlexus'
Cynodon dactylon 'Bermuda Tifton 419''"Pers. x C. transvaalensis Burtt Davy
Cynodon spp., Cultivars: 'Sunstar', '13 -14 ',' SWI-1003 ',
SWI-1012, SWI-1014, SWI-1044, SWI-1045, SWI-1046, Arizona Common, Numex Sahara, Princess 77 , Mohawk, FMC-6, SWI-1001, Sundevil, Southern Star, Riviera, Transcontinental, CIS-CD5, CIS-CD6, CIS-CD7 ',' Panama ',' La Paloma ',' Yukon ',' TiftNo. 1 ',' TiftNo. 2 ', and' Sunbird '. Vegetative cultivars included 'TiftNo. 3, TiftNo, 4, Tifway, Midlawn, Tifsport, MS-Choice, Aussie Green, GN-1, Premier, Ashmore, Patriot 'OKC 70-18', and 'Celebration'. 'Transcontinental'. Aussie Green, MS-Choice, Princess 77, SWI-045, SWI-1041, and SWI-1012. 'SWI-1014', 'Arizona Common',
'Sundevil', 'SR 9554', 'GN-1', and 'Patriot'.
Zoysia japonica cv. Lanyin 'Manila', {'Crowne', Z. japonica Steud., 'EIToro', Z. japonica Steud., 'Meyer', 'Cavalier'
[Z. matrella (L.) Merr.],
Hemarthria compressa (L. f) R. Br.
Dactylis glomerata L.
Agrostis stolonifera L. 'Penn A-4';"PennCross"
Agrostis canina L. 'Vesper', '7001', and 'Penn A-4',
Agrostis capillaris 'Leikvin', 'Nor'
Lolitan perenne
Microlaena stipoides (Labill.) R. Br. Var. Stipoides

It It should be noted at this point that the inventive Use or the inventive method in the cultivation of plants at each stage of the rearing process can take place. It is possible (and insofar one too preferred embodiment of the present invention), the use or the process take place in young plants, the raised in the superabsorbent rearing medium from the beginning become. On the other hand, it is also possible (and thus also a preferred embodiment of the present invention) that plants are first grown "conventionally" and then further growth according to the present invention.

• – Gemäß einer vorteilhaften Ausgestaltung des vorliegenden Verfahrens befindet sich der Superabsorber im Aufzuchtmedium, d. h. in den meisten Fällen wird dieses vor der Aufzucht der Pflanzen in den Boden eingearbeitet. Während der eigentlichen Aufzucht sind – abgesehen von einer gründlichen Bewässerung vor dem Einpflanzen – jedoch bei den meisten Anwendungen der vorliegenden Erfindung meist keine besonderen Schritte oder Vorsichtsmaßnahmen nötig. Somit ist eine Förderung des Wurzelwachstums durch effiziente und unkomplizierte Maßnahmen möglich.
• – Die Verwendung bzw. das Verfahren eignet sich für eine Automatisierung genauso wie für einen Einsatz im Großmaßstab, auch wenn prinzipiell die Verwendung und/oder das Verfahren nicht darauf beschränkt ist.
• – Die vorliegende Erfindung umfasst keine wesentliche Beeinflussung, insbesondere keine Schädigung der Umwelt.
• – Zum Einsatz oder Anwendung der vorliegenden Erfindung sind keine besonderen Fachkenntnisse erforderlich, so dass die Erfindung weltweit und insbesondere in Gegenden eingesetzt werden kann, wo kein ausgebildetes Personal wie Agraringenieure etc. zur Verfügung stehen.
• – Überraschenderweise wurde bei vielen Anwendungen der vorliegenden Erfindung festgestellt, dass das erhöhte Wurzelwachstum schon nach kurzer Zeit, d. h. nach ein oder zwei Monaten feststellbar ist.

Due to the surprising effect of the use according to the invention or of the method according to the invention, one or more of the following advantages can be achieved, in particular in many applications:

• - According to an advantageous embodiment of the present method, the superabsorbent is in the rearing medium, ie in most cases, this is incorporated before the rearing of the plants in the soil. However, during the actual rearing, apart from thorough pre-plant watering, most of the applications of the present invention usually require no special steps or precautions. Thus, the promotion of rooting through efficient and straightforward measures is possible.
• - The use or the method is suitable for automation as well as for use on a large scale, even if in principle the use and / or the method is not limited thereto.
• - The present invention includes no significant influence, in particular no damage to the environment.
• No particular expertise is required for the use or application of the present invention, so that the invention can be used worldwide and in particular in areas where no trained personnel, such as agricultural engineers, etc., are available.
• Surprisingly, it has been found in many applications of the present invention that the increased root growth is detectable after a short time, ie after one or two months.

The basic use of superabsorbers in soils has long been state of the art. In this context, inter alia, on the DE 198 13 425 A1 or the US Pat. No. 6,484,441 B1 referenced, which are hereby incorporated by citation. However, the totally surprising inventive effect underlying this invention is not described in these references and is reported here for the first time.

An advantageous and insofar preferred embodiment of the present method includes that the superabsorbent in the growth medium in a concentration of ≥ 0.1% to ≤ 1% (dry matter / wt dry medium) is present. This has proven particularly useful in practice. Particularly preferred is the range of ≥ 0.2% to ≤ 0.8%, more preferably ≥ 0.3% to ≤ 0.7%, and most preferably ≥ 0.4% to ≤ 0.6%.

According to one preferred embodiment of the present invention are> 90% of the superabsorbent at a depth of ≥ 0 to ≤ 50 cm.

Instead of The term "superabsorbents" are also designations like "high swellable polymer" "hydrogel" (often also used for the dry form), "hydrogel forming polymer "," water-absorbent polymer "," absorbent polymer gel-forming material "," swellable Resin "," water-absorbent resin ", Water-absorbing polymer "or the like in use. In all cases, these are in particular networked ones hydrophilic polymers, in particular polymers of (co) polymerized hydrophilic monomers, graft (co) polymers of one or more hydrophilic monomers on a suitable graft, crosslinked Cellulose or starch ethers, crosslinked carboxymethyl cellulose, partially crosslinked polyalkylene oxide or in aqueous Liquid swellable natural products, such as Guar derivatives, with superabsorbers based on partially neutralized Acrylic acid are most prevalent. The essential Properties of superabsorbers are their abilities, a multiple of their own weight of aqueous liquids to absorb and the liquid also under some Not to give up pressure again. The superabsorbent, in the form of a dry powder is used, changes in fluid intake in a gel, according to the usual water absorption into a superabsorber. The networking is for synthetic Superabsorber essential and an important difference to usual pure thickeners, as they contribute to the insolubility of the polymers in water. Soluble substances would be not usable as superabsorber. By far the most important The field of application of superabsorbents is the absorption of body fluids. Superabsorbents are used, for example, in diapers for toddlers, Incontinence products for adults or feminine hygiene products used. Other fields of application are, for example, as water-retaining agents in agricultural horticulture, as water storage for protection against fire, for liquid absorption in food packaging or in general for the absorption of Humidity.

superabsorbent can absorb a multiple of their own weight in water and withhold under some pressure. In general, points Such a superabsorber has a CRC ("Centrifuge Retention Capacity", Measuring method, see below) of at least 5 g / g, preferably at least 10 g / g and in a particularly preferred form at least 15 g / g. A "superabsorbent" can also be a mixture be materially different individual superabsorber or a mixture of components that only work together in superabsorbent properties show, it comes here less on the material composition on than on the superabsorbent properties.

Important for a superabsorbent is not just its absorption capacity, but also the ability to submerge fluid Retain pressure (retention, usually as "absorption under Load "(" AUL ") or" Absorption against Pressure "(" AAP ") expressed) and the liquid transport in the swollen state (mostly as "Saline Flow Conductivity" ("SFC") expressed). Swollen gel can transport liquids hinder until not swollen superabsorbent to prevent ("Gel blocking"). Good transport properties for liquids, for example, have superabsorbers, which have a high gel strength in the swollen state. gels with low gel strength are under applied pressure (Body pressure) deformable, clog pores in the superabsorbent / cellulose fiber absorbent body and thereby prevent further fluid intake. An increased gel strength is usually by a higher degree of crosslinking achieved, but this absorption capacity of the product is reduced. An elegant way to increase The gel strength represents the increase in the degree of crosslinking on the surface of the superabsorbent particles opposite the interior of the particles. This is usually dried in a surface postcrosslinking step Superabsorbent particles with average crosslink density one additional crosslinking in a thin surface layer subjected to their particles. Through the surface postcrosslinking increases the crosslink density in the shell of the superabsorbent particles, which reduces the absorption under pressure to a higher level Level is raised. While the absorption capacity in the surface layer of the superabsorbent particles decreases, has its core through the presence of mobile polymer chains an improved absorption capacity compared to the shell on, so that through the shell structure improved fluid transfer is ensured without gel blocking occurs. It is also known, overall higher crosslinked superabsorbent to generate and the degree of crosslinking in the interior of the particles opposite an outer shell of the particles later to reduce.

Furthermore, "superabsorber" in the context of the present invention crosslinked hydrophilic polymers, especially polymers of (co) polymerized hydrophilic monomers, graft (co) polymers of one or more hydrophilic monomers on a suitable graft base, crosslinked cellulose or starch ethers, crosslinked carboxymethyl cellulose, partially crosslinked polyalkylene oxide or natural products swellable in aqueous liquids, such as guar derivatives understood.

Prefers the at least one superabsorber has a swelling capacity in distilled water of at least ≥ 80 g / g, preferably at least ≥ 120 g / g and in a particularly preferred form at least ≥ 180 g / g as well as a CRC ("Centrifuge Retention Capacity ") of at least ≥ 40 g / g, preferably at least ≥ 80 g / g, and most preferably Form at least ≥ 100 g / g.

• a) mindestens ein ethylenisch ungesättigtes, säuregruppentragendes Monomer,
• b) mindestens einen Vernetzer,
• c) wahlweise ein oder mehrere mit dem Monomeren a) copolymerisierbare ethylenisch und/oder allylisch ungesättigte Monomere und
• d) wahlweise ein oder mehrere wasserlösliche Polymere, auf die die Monomere a), b) und gegebenenfalls c) zumindest teilweise aufgepfropft werden können,

erhalten.The at least one superabsorber is preferably obtained by polymerization of a monomer solution containing

• a) at least one ethylenically unsaturated, acid group-carrying monomer,
• b) at least one crosslinker,
• c) optionally one or more with the monomer a) copolymerizable ethylenically and / or allylic unsaturated monomers and
• d) optionally one or more water-soluble polymers to which the monomers a), b) and optionally c) can be at least partially grafted,

receive.

suitable Monomers a) are, for example, ethylenically unsaturated Carboxylic acids, such as acrylic acid, methacrylic acid, Maleic acid, fumaric acid and itaconic acid, or their derivatives, such as acrylamide, methacrylamide, acrylic esters and methacrylic acid esters. Particularly preferred monomers are acrylic acid and methacrylic acid. Most notably preferred is acrylic acid.

The Monomers a), in particular acrylic acid, preferably contain up to 0.025% by weight of a hydroquinone half-ether. Preferred hydroquinone half ethers are hydroquinone monomethyl ether (MEHQ) and / or tocopherols.

wobei R³ Wasserstoff oder Methyl, R⁴ Wasserstoff oder Methyl, R⁵ Wasserstoff oder Methyl und R⁴ Wasserstoff oder einen Säurerest mit 1 bis 20 Kohlenstoffatomen bedeutet. Bevorzugte Reste für R⁶ sind Acetyl, Ascorbyl, Succinyl, Nicotinyl und andere physiologisch verträgliche Carbonsäuren. Die Carbonsäuren können Mono-, Di- oder Tricarbonsäuren sein.Tocopherol is understood in particular to mean compounds of the following formula

wherein R ^{3 is} hydrogen or methyl, R ^{4 is} hydrogen or methyl, R ^{5 is} hydrogen or methyl and R ^{4 is} hydrogen or an acid radical having 1 to 20 carbon atoms. Preferred radicals for R ⁶ are acetyl, ascorbyl, succinyl, nicotinyl and other physiologically acceptable carboxylic acids. The carboxylic acids may be mono-, di- or tricarboxylic acids.

Preference is given to alpha-tocopherol with R ³ = R ⁴ = R ⁵ = methyl, in particular racemic alpha-tocopherol. R ⁶ is particularly preferably hydrogen or acetyl. Especially preferred is RRR-alpha-tocopherol.

The Monomer solution preferably contains at most 130 ppm by weight, more preferably at most 70 ppm by weight, preferably at least 10 ppm by weight, more preferably at least 30 Ppm by weight, in particular by 50 ppm by weight, hydroquinone, in each case based on acrylic acid, wherein acrylic acid salts to be considered as acrylic acid. For example For example, to prepare the monomer solution, an acrylic acid used with a corresponding content of hydroquinone half-ether become.

The Crosslinkers b) are compounds having at least two polymerizable Groups that radically polymerized into the polymer network can be. Suitable crosslinkers b) are, for example Ethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, Trimethylolpropane triacrylate, triallylamine, tetraallyloxyethane, di- and triacrylates, mixed acrylates, in addition to acrylate groups more contain ethylenically unsaturated groups, or crosslinker mixtures.

Suitable crosslinkers b) are, in particular, N, N'-methylenebisacrylamide and N, N'-methylenebismethacrylamide, esters of unsaturated monocarboxylic or polycarboxylic acids of polyols, such as diacrylate or triacrylate, for example butanediol or ethylene glycol diacrylate or methacrylate, and trimethylolpropane triacrylate and Al lylverbindungen, as Allyl (meth) acrylate, Triallylcyanurat, Maleinsäurediallylester, Polyallylester, Tetraallyloxyethan, Triallylamin, Tetraallylethylenediamine, Allylester of the phosphoric acid as well as Vinylphosphonsäurederivate, as for example in EP 343 427 A2 are described. Further suitable crosslinkers b) are pentaerythritol di-, pentaerythritol tri- and pentaerythritol tetraallyl ethers, polyethylene glycol diallyl ether, ethylene glycol diallyl ether, glycerol di- and glycerol triallyl ethers, polyallyl ethers based on sorbitol, and ethoxylated variants thereof. Useful in the process according to the invention are di (meth) acrylates of polyethylene glycols, wherein the polyethylene glycol used has a molecular weight between 300 and 1000.

Especially advantageous crosslinkers b) are, however, di- and triacrylates of the 3 to 15-fold ethoxylated glycerol, the 3- to 15-fold ethoxylated Trimethylolpropane, 3 to 15 times ethoxylated trimethylolethane, in particular di- and triacrylates of the 2- to 6-fold ethoxylated Glycerol or trimethylolpropane, the 3-fold propoxylated glycerol or trimethylolpropane, as well as the 3-fold mixed ethoxylated or propoxylated glycerol or trimethylolpropane, 15-fold ethoxylated glycerol or trimethylolpropane, as well as the 40-fold ethoxylated glycerol, trimethylolethane or trimethylolpropane.

All Particularly preferred crosslinkers b) are those with acrylic acid or methacrylic acid esterified to di- or triacrylates polyethoxylated and / or propoxylated glycerin. Especially advantageous di- and / or triacrylates of 3 to 10 times ethoxylated Glycerol. Very particular preference is given to di- or triacrylates of 1- to 5-fold ethoxylated and / or propoxylated glycerol. At the Most preferred are the triacrylates of 3 to 5 times ethoxylated and / or propoxylated glycerol. These are characterized by special low residual levels (typically below 10 ppm by weight) in the water-absorbent Polymer from and the aqueous extracts of the produced therewith Water-absorbing polymers have almost unchanged surface tension (typically at least 0.068 N / m) compared to water of the same Temperature up.

With the monomers a) copolymerizable ethylenically unsaturated Monomers c) are, for example, acrylamide, methacrylamide, crotonamide, Dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, Diethylaminopropyl acrylate, dimethylaminobutyl acrylate, dimethylaminoethyl methacrylate, Diethylaminoethyl methacrylate, dimethylaminoneopentyl acrylate and Dimethylaminoneopentyl.

When water-soluble polymers d) may be polyvinyl alcohol, Polyvinylpyrrolidone, starch, starch derivatives, polyglycols, formally wholly or partially polymers of vinylamine monomers such as partially or fully hydrolyzed polyvinylamide (so-called "polyvinylamine") or polyacrylic acids, preferably polyvinyl alcohol and starch.

The Polymerization is optionally in the presence of conventional polymerization carried out. Suitable polymerization regulators are, for example Thio compounds, such as thioglycolic acid, mercaptoalcohols, z. 2-mercaptoethanol, mercaptopropanol and mercaptobutanol, dodecylmercaptan, Formic acid, ammonia and amines, e.g. Ethanolamine, diethanolamine, Triethanolamine, triethylamine, morpholine and piperidine.

The Monomers (a), (b) and optionally (c) are optionally in the presence the water-soluble polymer d), in 20 to 80, preferably 20 to 50, in particular 30 to 45 wt .-% aqueous Solution in the presence of polymerization initiators together (Co) polymerized. As polymerization initiators can all under the polymerization conditions into radicals decomposing compounds are used, for. B. peroxides, hydroperoxides, Hydrogen peroxide, persulfates, azo compounds and the so-called redox initiators. Preference is given to the use of water-soluble initiators. In some cases, it is advantageous to mix different To use polymerization initiators, for. B. mixtures of hydrogen peroxide and sodium or potassium peroxodisulfate. Mixtures of hydrogen peroxide and sodium peroxodisulfate can be in any ratio be used. Suitable organic peroxides are, for example, acetylacetone peroxide, Methyl ethyl ketone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert-amyl perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate, tert-butyl perisobutyrate, tert-butyl per-2-ethylhexanoate, tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl perbenzoate, tert-butyl per 3,5,5-tri-methylhexanoate and tert-Amylperneodekanoat. Other suitable polymerization initiators are azo starters, z. 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N-dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4,4'-azobis (4-cyanovaleric acid). The mentioned polymerization initiators are used in conventional amounts, eg. B. in amounts of 0.01 to 5, preferably 0.1 to 2 mol%, based on the polymerizable Monomers.

The redox initiators contain as oxidizing component at least one of the above Per compounds and a reducing component, for example, ascorbic acid, glucose, sorbose, ammonium or alkali metal hydrogen sulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or sulfide, metal salts such as ferrous ion or silver ion or sodium hydroxymethyl sulfoxylate. As reducing component of the redox initiator, ascorbic acid or sodium pyrosulfite is preferably used. Based on the amount of monomers used in the polymerization, use is made of 1 × 10 ^-5 to 1 mol% of the reducing component of the redox initiator and 1 × 10 ^-5 to 5 mol% of the oxidizing component. Instead of the oxidizing component or in addition one can also use one or more water-soluble azo initiators.

Preference is given to using a redox initiator consisting of hydrogen peroxide, sodium peroxodisulfate and ascorbic acid. For example, these components are used in the concentrations 1 × 10 ^-2 mol% of hydrogen peroxide, 0.084 mol% of sodium peroxodisulfate and 2.5 × 10 ^-3 mol% of ascorbic acid, based on the monomers.

The aqueous monomer solution can be dissolved the initiator or dispersed. The initiators can do that Polymerization reactor, however, also separated from the monomer solution be supplied.

The preferred polymerization inhibitors require an optimal effect dissolved oxygen. Therefore, you can the polymerization inhibitors before the polymerization by inerting, d. H. Flowing through with an inert gas, preferably Nitrogen, to be freed of dissolved oxygen. This happens by means of inert gas, which in cocurrent, countercurrent or intermediate inlet angles can be initiated. A good mixing can be done, for example, with nozzles, static or dynamic mixers or bubble columns. Preferably, the oxygen content of the monomer solution before the polymerization to less than 1 ppm by weight, more preferably to less than 0.5 ppm by weight, lowered. The monomer solution is optionally passed through the reactor with an inert gas stream.

• • Gelpolymerisation im Batchverfahren bzw. Rohrreaktor und anschließender Zerkleinerung im Fleischwolf, Extruder oder Kneter.
• • Polymerisation im Kneter, wobei durch beispielsweise gegenläufige Rührwellen kontinuierlich zerkleinert wird.
• • Polymerisation auf dem Band und anschließende Zerkleinerung im Fleischwolf, Extruder oder Kneter.
• • Emulsionspolymerisation, wobei bereits Perlpolymerisate relativ enger Gelgrößenverteilung anfallen.
• • In-situ Polymerisation einer Gewebeschicht, die zumeist im kontinuierlichen Betrieb zuvor mit wässriger Monomerlösung besprüht und anschließend einer Photopolymerisation unterworfen wurde.

The at least one superabsorber is preferably obtained by polymerization of an aqueous monomer solution and optionally subsequent comminution of the superabsorber. Suitable manufacturing methods are z. B.

• Gel polymerization in a batch process or tubular reactor and subsequent comminution in a meat grinder, extruder or kneader.
• • Polymerization in the kneader, which is continuously comminuted by, for example, counter-rotating stirrer shafts.
• • Polymerization on the belt and subsequent comminution in the meat grinder, extruder or kneader.
• Emulsion polymerization, in which bead polymers of relatively narrow gel size distribution are already produced.
• In-situ polymerization of a fabric layer, which was sprayed previously in continuous operation previously with aqueous monomer solution and then subjected to photopolymerization.

The The reaction is preferably carried out in a kneader or on a belt reactor carried out.

One in the context of this invention is particularly preferred process the continuous gel polymerization. It will be first prepared a monomer mixture by adding to the acrylic acid solution in temporally and / or spatially separate addition, the Neutralizing agent, optional comonomers and / or other auxiliaries are added and the mixture is then transferred to the reactor is, or is already submitted in the reactor. As a last addition the dosing of the initiator system takes place at the start of the polymerization. in the subsequent continuous polymerization process the reaction to the polymer gel (i.e., that in the solvent the polymerization - usually water - to Gel swollen polymer), which in the case of a stirred Polymerization is already crushed in advance. The polymer gel is then dried, if necessary, too crushed crushed and sieved and transferred for further surface treatment.

The acid groups of the superabsorbents obtained are usually partially neutralized, generally at least ≥25 mol%, preferably at least ≥27 mol%, and more preferably at least ≥40 mol%, and generally at most ≤85 mol%, preferably at most ≦ 80 mol% and in a particularly preferred form at most ≦ 75 mol%, to which the customary neutralizing agents can be used, preferably alkali metal hydroxides, alkali metal oxides, alkali metal carbonates or alkali metal bicarbonates and mixtures thereof. Instead of alkali metal salts and ammonium salts can be used. Sodium and potassium are particularly preferred as alkali metals, most preferably, however, sodium hydroxide, sodium carbonate or sodium bicarbonate and mixtures thereof. Usually, the neutralization is achieved by mixing the neutralizing agent as an aqueous solution or preferably as a solid. For example, sodium hydroxide with a water content well below ≤ 50 wt .-% present as a waxy mass with a melting point above ≥ 23 ° C. In this case, a dosage as general cargo or melt at elevated temperature is possible.

The Neutralization may occur after the polymerization at the hydrogel stage be performed. But it is also possible the neutralization to the desired degree of neutralization completely or partially before the polymerization. In case of partial neutralization before the polymerization are generally at least ≥ 10 mol%, preferably at least ≥ 15 Mol%, and generally at most ≤ 40 mol%, preferably at most ≦ 30 mol% and in particular Preferred form at most ≤ 25 mol% of the acid groups neutralized in the monomers used before the polymerization, by a part of the neutralizing agent already the monomer solution is added. The desired final degree of neutralization becomes in this case, towards the end or after the polymerization, preferably adjusted at the level of the hydrogel before drying. The Monomer solution is prepared by mixing in the neutralizing agent neutralized. The superabsorbent can be mechanically neutralized be crushed, for example by means of a meat grinder or comparable apparatus for comminuting gel-like masses, wherein the neutralizing agent sprayed on, scattered or infused and then mixed thoroughly. For this purpose, the gel mass obtained several more times for homogenization be helped.

In preferred form is the monomer solution before polymerization by adding the neutralizing agent to the desired Endeutralisationsgrad set.

The gels obtained from the polymerization are optionally given some time, for example at least ≥ 30 minutes, preferably at least ≥ 60 Minutes, and more preferably at least ≥ 90 minutes and generally at most ≤ 12 hours, preferably at most ≤ 8 hours, and more preferably Shape at most ≤ 6 hours at a temperature of generally at least ≥ 50 ° C, and preferably at least ≥ 70 ° C and generally at most ≤ 130 ° C and preferably kept at most ≦ 100 ° C, which often improves their properties.

Of the neutralized superabsorbent is then treated with a belt or drum dryer dried until the residual moisture content is preferably below ≦ 15 Wt .-%, in particular less than ≤ 10 wt .-%, wherein the Water content according to the method described by EDANA (European Disposables and Nonwovens Association) recommended test method no. 430.2-02 "Moisture Content" is determined. Of the dry superabsorbent thus contains up to ≤ 15 % By weight of moisture, preferably at most ≦ 10 Wt .-%. Decisive for the classification as "dry" is especially for handling as a powder (such as for pneumatic Promotion, bottling, screening or other procedural steps from the solid process technology) sufficient flowability. Optionally, for drying but also a fluidized bed dryer or a heated ploughshare mixer can be used. To be especially colorless To obtain products, it is beneficial in drying this Gels to ensure a quick removal of the evaporating water. For this purpose, the dryer temperature is to be optimized, the air supply and removal must be controlled, and it is sufficient in any case Respect ventilation. The drying is naturally all the more easier and the product the more colorless the higher the Solid content of the gel is. The solvent content at The polymerization is therefore adjusted so that the solids content of the gel before drying therefore generally at least ≥ 20 Wt .-%, preferably at least ≥ 25 wt .-% and in particularly preferred form at least ≥ 30 wt .-% and generally at most ≦ 90% by weight, preferably at most ≦ 85% by weight, and more preferably Form is at most ≤ 80 wt .-%. Especially advantageous is the ventilation of the dryer with nitrogen or another non-oxidizing inert gas. Optionally, though also just the partial pressure of oxygen during the drying can be lowered to oxidative yellowing to prevent. As a rule, but also leads to a sufficient Ventilation and removal of water vapor to one still acceptable product. Advantageous in terms of color and product quality is usually the shortest possible drying time.

The dried hydrogel (which is no gel anymore - though often called that way - but a dry polymer with superabsorbent properties that fall under the term "superabsorbent") is preferably ground and sieved, with the grinding usually Roller mills, pin mills, hammer mills, Cutting mills or vibrating mills are used can. The particle size of the sieved, dry superabsorbent is preferably below ≦ 1000 μm, particularly preferably below ≦ 900 μm, very particularly preferably below ≦ 850 μm, and preferably above ≦ 800 μm, more preferably over ≥ 90 microns, especially preferably over ≥ 100 μm.

Very particular preference is given to a particle size (sieve cut) of ≥ 106 to ≦ 850 μm. Particle size is determined according to the recommendations of EDANA (European Disposables and Nonwovens Association) Test Method No. 420.2-02 "Particle size distribution" determined.

• • Di- oder Polyepoxide, etwa Di- oder Polyglycidylverbindungen wie Phosphonsäurediglycidylester, Ethylenglykoldiglycidylether oder Bischlorhydrinether von Polyalkylenglykolen,
• • Alkoxysilylverbindungen,
• • Polyaziridine, Aziridin-Einheiten enthaltende Verbindungen auf Basis von Polyethern oder substituierten Kohlenwasserstoffen, beispielsweise Bis-N-Aziridinomethan,
• • Polyamine oder Polyamidoamine sowie deren Umsetzungsprodukte mit Epichlorhydrin,
• • Polyole wie Ethylenglykol, 1,2-Propandiol, 1,4-Butandiol, Glycerin, Methyltriglykol, Polyethylenglykole mit einem mittleren Molekulargewicht Mw von 200–10000, Di- und Polyglycerin, Pentaerythrit, Sorbit, die Oxethylate dieser Polyole sowie deren Ester mit Carbonsäuren oder der Kohlensäure wie Ethylencarbonat oder Propylencarbonat,
• • Kohlensäurederivate wie Harnstoff, Thioharnstoff, Guanidin, Dicyandiamid, 2-Oxazolidinon und dessen Derivate, Bisoxazolin, Polyoxazoline, Di- und Polyisocyanate,
• • Di- und Poly-N-methylolverbindungen wie beispielsweise Methylenbis(N-methylol-methacrylamid) oder Melamin-Formaldehyd-Harze,
• • Verbindungen mit zwei oder mehr blockierten Isocyanat-Gruppen wie beispielsweise Trimethylhexamethylendiisocyanat blockiert mit 2,2,3,6-Tetramethyl-piperidinon-4.

The dry superabsorbent polymers thus prepared are commonly referred to as "base polymers" and preferably subsequently surface postcrosslinked. The surface postcrosslinking can be carried out in a manner known per se with dried, ground and screened polymer particles. For this purpose, compounds which can react with the functional groups of the base polymer with crosslinking, usually applied in the form of a solution to the surface of the base polymer particles. Suitable postcrosslinkers are, for example:

• Di- or polyepoxides, for example di- or polyglycidyl compounds, such as phosphonic acid diglycidyl esters, ethylene glycol diglycidyl ethers or bischlorohydrin ethers of polyalkylene glycols,
• Alkoxysilyl compounds,
• Polyaziridines, compounds containing aziridine units based on polyethers or substituted hydrocarbons, for example bis-N-aziridinomethane,
• Polyamines or polyamidoamines and their reaction products with epichlorohydrin,
• Polyols such as ethylene glycol, 1,2-propanediol, 1,4-butanediol, glycerol, methyltriglycol, polyethylene glycols having an average molecular weight M w of 200-10000, di- and polyglycerol, pentaerythritol, sorbitol, the oxyethylates of these polyols and their esters with carboxylic acids or carbonic acid, such as ethylene carbonate or propylene carbonate,
• Carbonic acid derivatives such as urea, thiourea, guanidine, dicyandiamide, 2-oxazolidinone and its derivatives, bisoxazoline, polyoxazolines, di- and polyisocyanates,
• Di- and poly-N-methylol compounds such as, for example, methylenebis (N-methylol-methacrylamide) or melamine-formaldehyde resins,
• Compounds with two or more blocked isocyanate groups such as trimethylhexamethylene diisocyanate blocked with 2,2,3,6-tetramethylpiperidinone-4.

at Need can acidic catalysts such as p-toluenesulfonic acid, Phosphoric acid, boric acid or ammonium dihydrogen phosphate be added.

Especially suitable postcrosslinkers are di- or polyglycidyl compounds such as ethylene glycol diglycidyl ether, the reaction products of polyamidoamines with epichlorohydrin, 2-oxazolidinone and N-hydroxyethyl-2-oxazolidinone.

The Surface postcrosslinking (often only "postcrosslinking") is usually done so that a Solution of surface postcrosslinker (often also only "postcrosslinker") on the superabsorber or the dry base polymer powder is sprayed on.

When Solvent for the surface postcrosslinker a common suitable solvent is used For example, water, alcohols, DMF, DMSO and mixtures thereof. Particularly preferred are water and water / alcohol mixtures such as For example, water / methanol, water / isopropanol, water / 1,2-propanediol and water / 1,3-propanediol.

The spraying of a solution of the postcrosslinker is preferably carried out in mixers with agitated mixing tools, such as screw mixers, paddle mixers, disk mixers, ploughshare mixers and paddle mixers. Vertical mixers are particularly preferred, plowshare mixers and paddle mixers are very particularly preferred. Suitable and known mixers include for example Lödige ^® - Bepex ^® - Nauta ^® - Processall® ^® - and Schugi ^® mixer. Very particular preference high-speed mixer, for example of the Schugi Flexomix ^® or Turbolizer ^®, are used.

After the crosslinker solution has been sprayed on, a temperature treatment step, essentially for carrying out the surface postcrosslinking reaction (yet usually only referred to as "drying"), may optionally follow, preferably in a downstream heated mixer ("dryer"), at a temperature of generally at least ≥ 50 ° C, preferably at least ≥ 80 ° C and in a particularly preferred form at least ≥ 90 ° C and generally at most ≤ 250 ° C, preferably at most ≤ 200 ° C and in a particularly preferred form at most ≤ 150 ° C. The mean residence time (ie the average residence time of the individual superabsorber particles) of the superabsorbent to be treated in the dryer is generally at least ≥ 1 minute, preferably at least ≥ 3 minutes and in a particularly preferred form at least ≥ 5 minutes and generally at most ≦ 6 hours, preferably at most ≤ 2 hours, and most preferably at most ≤ 1 hour. In this case, not only the actual drying but also any existing cleavage products and solvent components are removed. The thermal drying is in conventional dryers such as tray dryers, rotary kilns or heated screws, preferably in Kon cycle dryers carried out. Preferably, the use of dryers in which the product is moved, ie heated mixers, particularly preferably paddle dryers, most preferably disc dryers. Suitable dryers are, as example Bepex ^® dryers and Nara ^® dryers. Moreover, fluidized bed dryers can also be used. The drying can also be done in the mixer itself, by heating the jacket or blowing a preheated gas such as air. However, it is also possible, for example, to use an azeotropic distillation as the drying process. The crosslinking reaction can take place both before and during drying.

In a particularly preferred embodiment of the invention, in addition, the hydrophilicity of the particle surface of the base polymers is modified by forming complexes. The formation of the complexes on the outer shell of the particles is carried out by spraying solutions of divalent or polyvalent cations, wherein the cations can react with the acid groups of the polymer to form complexes. Examples of divalent or polyvalent cations are polymers which are formally wholly or partially composed of vinylamine monomers, such as partially or completely hydrolyzed polyvinylamide (so-called "polyvinylamine"), whose amine groups are always partially protonated to ammonium groups, even at very high pH values, or metal cations such as Mg ²⁺ , Ca ²⁺ , Al ³⁺ , Sc ³⁺ , Ti ⁴⁺ , Mn ²⁺ , Fe ^{2+ / 3+} , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , Y ³⁺ , Zr ⁴⁺ , La ³⁺ , Ce ⁴⁺ , Hf ⁴⁺ , and Au ³⁺ . Preferred metal cations are Mg ²⁺ , Ca ²⁺ , Al ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ and La ³⁺ , and particularly preferred metal cations are Al ³⁺ , Ti ⁴⁺ and Zr ⁴⁺ . The metal cations can be used both alone and in a mixture with each other. Of the cited metal cations, all metal salts which have sufficient solubility in the solvent to be used are suitable. Particularly suitable are metal salts with weakly complexing anions such as chloride, nitrate and sulfate, hydrogen sulfate, carbonate, bicarbonate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate and carboxylate such as acetate and lactate. In a particularly preferred form, aluminum sulfate is used. As solvents for the metal salts, water, alcohols, DMF, DMSO and mixtures of these components can be used. Particularly preferred are water and water / alcohol mixtures such as water / methanol, water / isopropanol, water / 1,2-propanediol and water / 1,3-propanediol.

The Treatment of the base polymer with a solution of two or polyvalent cation occurs in the same way as with surface postcrosslinker, including the optional drying step. surface post and polyvalent cation can be in a common solution or sprayed as separate solutions. Spraying the metal salt solution onto the superabsorbent particles can be used both before and after surface postcrosslinking respectively. In a particularly preferred method, the spraying takes place the metal salt solution in the same step with the spraying the crosslinker solution, with both solutions separated successively or simultaneously via two nozzles be sprayed, or crosslinker and metal salt solution can be sprayed together via a nozzle can.

If a drying step is carried out after the surface postcrosslinking and / or treatment with complexing agent, it is advantageous, but not absolutely necessary, to cool the product after drying. The cooling can be continuous or discontinuous, conveniently the product is continuously conveyed to a dryer downstream cooler. Any apparatus known for removing heat from powdered solids may be used for this purpose, in particular any apparatus mentioned above as a drying apparatus, unless it is supplied with a heating medium but with a cooling medium, such as cooling water, so that over the walls and depending on the construction No heat is introduced into the superabsorber via the stirring elements or other heat exchange surfaces, but is removed therefrom. Preference is given to the use of coolers in which the product is moved, ie cooled mixers. For example, blade coolers, disc coolers or paddle coolers such as in Nara ^® or Bepex ^® coolers. The superabsorbent can also be cooled in the fluidized bed by blowing in a cooled gas such as cold air. The conditions of the cooling are adjusted so that a superabsorbent is obtained with the temperature desired for further processing. Typically, a mean residence time in the cooler of generally at least ≥ 1 minute, preferably at least ≥ 3 minutes and more preferably at least ≥ 5 minutes, and generally at most ≦ 6 hours, preferably at most ≦ 2 hours and most preferably at most ≦ 1 Adjusted hour and the cooling capacity so that the product obtained a temperature of generally at least ≥ 0 ° C, preferably at least ≥ 10 ° C and in a particularly preferred form at least ≥ 20 ° C and generally at most ≤ 100 ° C, preferably at most ≤ 80 ° C and in a particularly preferred form at most ≤ 60 ° C.

Optionally, a further modification of the superabsorbent by admixture of finely divided inorganic solids, such as silica, alumina, titanium dioxide and iron (II) oxide take place, whereby the effects of the surface treatment are further enhanced. Particularly preferred the admixture of hydrophilic silica or of aluminum oxide with an average size of the primary particles of ≥ 4 to ≦ 50 nm and a specific surface area of ≥ 50 - ≦ 450 m ² / g. The admixture of finely divided inorganic solids is preferably carried out after the surface modification by crosslinking / complex formation, but can also be carried out before or during these surface modifications.

Optional becomes the superabsorbent with other common additives and adjuvants, the storage or handling properties influence. Examples are coloring, opaque additives to increase the visibility of swollen gel improve what is desirable in some applications, Additives for improving the flow behavior of the Powders, surfactants or the like. Often the superabsorbent dust removal or dust binder added. Dedusting or dust binder are known, for example, polyether glycols such as polyethylene glycol with a molecular weight of ≥ 400 to ≤ 20 000 g / mol, polyols such as glycerol, sorbitol, neopentyl glycol or trimethylolpropane, which optionally also ethoxylates ≥ 7 to ≤ 20-fold are used. Also a finite water content of the superabsorbent can be adjusted by adding water, if desired.

The Solids, additives and auxiliaries can each be added in separate steps, but usually is the most convenient way to admit it to the superabsorber in the radiator for example by spraying a solution or adding in finely divided solid or in liquid form.

Of the Surface-postcrosslinked superabsorbents are available in standard Milled and / or sieved. Grinding is typical here not necessary, but usually is to set the desired Particle size distribution of the product, the screening of formed agglomerates or fines. agglomerates and fine grain are either discarded or preferably in known Way and where appropriate in the process attributed; Agglomerates after comminution. The particle size the superabsorbent particle is preferably at most ≦ 1000 μm, more preferably at most ≦ 900 μm, most preferably at most ≦ 850 μm, and preferably at least ≥ 80 μm, especially preferably at least ≥ 90 microns, most preferably at least ≥ 100 μm. Typical sieve cuts are for example, 106 106 to 850 μm or ≥ 150 up to ≤ 850 μm.

• – Nutzpflanzenanbau
• – Rasenflächen
• – Golfplätze
• – Gemüseanbau
• – Baumwollplantagen
• – Aufforstungen
• – Zierpflanzenanbau
• – Treibhauskulturen
• – Kulturen mit bodenfreien Substraten

The present invention also relates to a use of the method according to the invention and / or use of the inventive use for or in connection with

• - crop cultivation
• - lawns
• - golf courses
• - vegetable cultivation
• - Cotton plantations
• - Afforestation
• - ornamental plant cultivation
• - greenhouse cultures
• - Cultures with soil-free substrates

The the aforementioned and the claimed and in the embodiments described to be used according to the invention Components and components are subject in size, shape, Material selection and technical conception no special exceptions, so that the selection criteria known in the field of application unrestricted Application can be found.

Further Details, features and advantages of the subject matter of the invention emerge from the dependent claims and from the following Description of the associated examples and drawings, in which several embodiments of the present invention are shown. In the drawings shows:

1 , a diagram showing the root root and leaf dry mass of test plants (Terminalia) in rearing attempts according to the present invention and control experiments;

2 Fig. 3 is a graph showing the increase of root growth in one embodiment of the present invention for various plant species;

3 a photo of three test plants (Terminalia superba) after rearing attempts according to an embodiment of the present invention and control experiments;

4 a photo of three other experimental plants (Araucaria cunninghamii) after breeding attempts according to an embodiment of the present invention as well as control experiments; such as

5 a photo of three other experimental plants (Grevillea robusta) after rearing attempts according to an embodiment of the present invention and control experiments;

6 Fig. 3 is a graph showing the increase of root growth in an embodiment of the present invention for golf turfs;

7 a photo of three experimental plants (golf turf) after rearing attempts according to two embodiments of the present invention and control experiments; such as

8th an excerpt from the photo 7

1 shows a diagram showing the root, stem and leaf dry mass of test plants (Terminalia) in rearing attempts according to the present invention and control experiments.

For this were three test plants of the species Terminalia (tropical wing seed plant) under otherwise identical conditions raised in a ground, the once no, once 0.2% and once 0.4% of the amount of a superabsorbent (Luquasorb, Fa. BASF). These plants were two and a half Months in the greenhouse with good irrigation (no Water stress).

As in 1 to see, the dry masses of stem and leaves in the three experiments are largely identical. However, when using the superabsorber, a significant increase in the root dry mass can be detected. A Luquasorb amount of 0.4% leads to a significant increase of the root mass to almost twice the dry mass of the control without Luquasorb.

2 Figure 9 is a graph showing the increase in rooting in one embodiment of the present invention for various plant species.

In each case a rearing without superabsorbent in the soil according to the conditions was 1 and with 0.4% by weight of Luquasorb, and the percentage increase in dry root mass was measured.

there could at least increase by 10% (in the case of Eucalyptus citriodora, it should be noted that here the culture medium Sandy soil), but in most plants used one Increase of 20% and more are found.

The exact results are given in Table 1. Table 1 experimental plant soil type Increase of root growth plant order Araucaria cunninghamii Cunningham's Araucaria Sandy clay 37% Pinales Azadirachta indica neem tree sand 17% Meliales Eucalyptus citriodora Lemon Eucalyptus sand 12% Myrtales Eucalyptus grandis redgum tree sand 33% Myrtales Grevillea robusta Australian Silras clayey clay 49% Proteales Grevillea robusta Australian Silras Clay 61% Proteales Maesopsis eminii sand 76% Rhamnales Terminalia superba Limba Clay 87% Myrtales

As in the 3 to 5 good to see is the increased root growth "healthy", ie there is both an extension of the main roots as well as an intensive training of lateral roots. In addition, the entire root system is stronger. The figures each show photos after breeding attempts among the 1 conditions with Terminalia superba [Limba, 3 ], Araucaria cunninghamii [Cunningham's Araucaria, 4 ], Grevillea robusta [Australian Silras, 4 ]

6 shows a diagram which the root dry mass of a golf grass mixture, as used on the golf course golf club Hardenberg, Levershausen, was obtained in rearing attempts according to the present invention and control experiments.

For this were experimental plants under otherwise identical conditions in one Raised the ground once, not even 0.2% and once 0.4% the amount of a superabsorbent (Luquasorb, BASF) contained. These Plants were two and a half months in the greenhouse at good Irrigation (no water stress) attracted. The missing of Water stress was measured by daily measurements of water potentials checked the soil.

As in 6 When using 0.4% Luquasorb, it was possible to increase the dry root mass by almost five times. The exact data are given in Table 2 Table 2 attempt Root mass (in g) control 25.23 0.2% SAP 28.14 0.4% SAP 93.28

7 and 8th show photos of the experimental and control plants. As can be clearly seen in the figures, the increased root growth is "healthy", ie there is both an extension of the main roots as well as an intensive formation of lateral roots. In addition, the entire root system is stronger.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 19813425 A1 [0018]
• - US 6484441 B1 [0018]
• - EP 343427 A2 [0033]

Claims (7)

Use of superabsorbents for promotion root growth of plants Use according to claim 1, wherein the superabsorbent is added to a growing medium or the growing medium the Superabsorber includes. Use according to claim 1 or 2, wherein the concentration of the superabsorbent in the culture medium ≥ 0.1% to ≤ 1% (Dry weight / weight of dry medium). Method for promoting root growth of plants grown in a growing medium, characterized in that the growth medium is a superabsorber is added and / or the growth medium comprises a superabsorbent. The method of claim 4, wherein the concentration of the superabsorbent in the growth medium ≥ 0.1% to <1% (dry matter / wt. of the dry medium). Method according to claim 4 or 5, wherein ≥ 90% of the superabsorbent at a depth of ≥ 0 to ≤ 50 cm are located. Use according to one of claims 1 to 3 or a method according to any one of claims 1 to 6 For - crop cultivation - lawns - golf courses - vegetable cultivation - Cotton plantations - Afforestation - ornamental plant cultivation - greenhouse cultures - Cultures with soil-free substrates