EP1644432A1

EP1644432A1 - Carrier for aqueous media

Info

Publication number: EP1644432A1
Application number: EP04740186A
Authority: EP
Inventors: Hartmut Stenzel; Erich Kessler; Quan Huang
Original assignee: Membrana GmbH
Current assignee: Membrana GmbH
Priority date: 2003-07-03
Filing date: 2004-06-23
Publication date: 2006-04-12
Also published as: CA2531080A1; BRPI0412035A; CN1816589A; US20070042183A1; WO2005003215A1; KR20060121804A; JP2007535581A; MXPA05014192A

Abstract

The invention relates to a carrier in the form of particles, which can be loaded with aqueous media. Said particles are formed from a porous hydrophobic polymer substrate, have an average particle size ranging between 50 µm and 5000 µm, and are provided with an at least partly open-pore structure having an average pore diameter ranging between 1 µm and 200 µm. The inventive carrier can be loaded with 10 to 95 percent by weight of water relative to the total weight of the loaded carrier, said loadability being determined by contacting the carrier with water. Also disclosed is a storage device which is based on said carrier and is loaded with an aqueous medium. The invention further relates to a method for producing such a carrier in the form of particles that are based on a hydrophobic polymer, said carrier being loadable with 10 to 95 percent by weight of water. According to said method, the polymer substrate that is provided in particles is hydrophilized on at least one portion of the entire surface thereof, which comprises the exterior surface and the surface of the pores thereof.

Description

Carrier for aqueous media

Description:

The invention relates to a carrier for aqueous media and a method for producing such a carrier for aqueous media.

For numerous applications there is a need for particulate carriers which are able to absorb water or generally aqueous media and, depending on the application, also to store them.

In plastics processing, for example, it is often necessary to mix solid or liquid additives in small concentrations into a polymer melt. Such additives can e.g. Antioxidants, plasticizers, fragrances, lubricants, antistatic agents, surface-active substances u. the like. A masterbatch process is often used for this, in which a concentrate of the additive to be incorporated is first prepared in a suitable polymer and this concentrate is then e.g. is incorporated into a polymer melt by means of an extrusion process with homogeneous distribution of the additive. Porous particulate polymer structures are often used to produce such masterbatches, in the pores of which the respective additive is introduced.

DE 2737 745 C2 describes microporous polymer structures which are produced by a process with thermally induced phase separation from a homogeneous melt of the polymer and an organic liquid which is compatible with the polymer. For one, after the DE 27 37 745 C2 produce structures which contain additives as functional active fluids, the functional active fluids at the same time being the compatible organic liquid used in the production of the polymer structures, which at least partially remains in the pore system after formation of the porous polymer structure. On the other hand, according to DE 27 37 745 C2, unfilled microporous structures can be produced, in the pore system of which additives can subsequently be introduced in organic solution via absorption mechanisms. Similar structures which can be loaded with additives can also be produced by the process described in DE 32 05289 C2.

WO 98/55540 describes porous polymer particles based on polyolefins. These polymer particles can be absorbed e.g. be loaded with liquid additives. For the loading of hydrophobic polymer particles, as disclosed in WO 98/55540, however, it is a prerequisite that the additives are hydrophobic additives. For absorption, i.e. the hydrophobic porous polymer particles of WO 98/55540 are not able to absorb aqueous media.

For a substantial part of the applications, hydrophobic polymers are required as carriers for additives or active liquids, ie, for example, polyolefins such as polyethylene, polypropylene or poly (4-methyl-1-pentene) or fluoropolymers such as polyvinylidene fluoride or polyvinyl fluoride. For example, such polymers are distinguished as such by properties such as high chemical resistance and / or physiological safety, high mechanical stability or temperature stability. But also for reasons of compatibility when used as a masterbatch, for example for incorporation into polyolefins, it is often necessary to use additive concentrates based on the aforementioned hydrophobic polymers. Porous polymer structures made from these polymers are good with their hydrophobic properties hydrophobic active liquids or hydrophobic liquids containing additives can be loaded.

However, a number of active fluids or additives are aqueous in nature. For example, numerous additives first in the form of an aqueous dispersion or emulsion, e.g. Dispersions of latex particles, color pigments, kaolin, nanoparticles, etc. However, such active liquids or additive dispersions cannot be absorbed by the known hydrophobic porous polymer particles, or at most to a very small extent, i.e. be included.

In the production of foams from thermoplastics, e.g. Water is often used as a blowing agent in the production of polyolefin foams. Here too, as with the additives mentioned above for plastic processing, there is the problem of homogeneously mixing the water in small concentrations into the polymer melts, which results in a need for suitable water-containing masterbatches. By means of the known e.g. Porous polymer structures based on polyolefin cannot, however, produce water-storing concentrates.

Ultimately there is also e.g. For air humidification or air conditioning, there is a need for pourable materials that contain large amounts of water and have a large surface area.

A number of products are known as so-called superabsorbers which are capable of being carriers for aqueous media and which can absorb many times their own weight in liquid and can even retain it under the highest pressure. Products of this type are based, for example, on cellulosic polymers or on modified polyacrylates, polyacrylonitriles or polyvinyl alcohols, ie on hydrophilic polymers. A disadvantage of such products However, it is often the case that they do not have sufficient mechanical stability and are not free-flowing. In addition, they are also unsuitable for absorbing, for example, aqueous dispersions, and compatibility problems arise when such products are incorporated into hydrophobic thermoplastic polymers such as, for example, polyolefins.

It is therefore an object of the present invention to provide a carrier which can be loaded with aqueous media and is based on a hydrophobic polymer and is capable of absorbing water or generally aqueous media and, depending on the application, of also storing and starting from the production of additive concentrates of aqueous additive dispersions. It is a further object of the present invention to provide a method for producing such carriers. Another object is to provide a storage for aqueous media based on a hydrophobic polymer.

The object is achieved by a carrier in the form of particles which can be loaded with aqueous media, the particles being formed from a porous hydrophobic polymer substrate, having an average particle size between 50 μm and 5000 μm and an at least partially open-pore structure with an average pore diameter between 1 μm and have 200 μm and wherein the particulate carrier has a loadability with water, determined by contacting with water, from 10% by weight to 95% by weight, based on the total weight of the loaded carrier.

The carrier according to the invention is therefore a porous polymer particle that can be loaded with aqueous media and is based on a hydrophobic polymer substrate. Since the carrier according to the invention is in the form of particles, it is capable of blowing or pouring, which is particularly advantageous for further processing. In a preferred embodiment of the invention, the porous polymer substrate is strat hydrophilized on at least a portion of its entire surface including the outer surface and the surface of its pores. It is particularly advantageous if the porous polymer substrate is hydrophilized on essentially its entire surface, which comprises the outer surface and the surface of its pores. This can be achieved with porous polymer substrates, the pore volume of which has a high proportion of accessible pores.

The object is further achieved by a method for producing a carrier which can be loaded with aqueous media in the form of particles based on a hydrophobic polymer, the carrier having a loadability with water, determined by bringing it into contact with water, from 10 to 95% by weight. based on the total weight of the loaded carrier, comprising the steps: - selection of a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 μm and an at least partially open-pore structure with an average pore diameter between 1 μm and 200 μm, - hydrophilizing the polymer substrate present in particles on at least part of its entire surface, which comprises the outer surface and the surface of its pores, in order to obtain the carrier which can be loaded with aqueous media.

The method according to the invention is particularly suitable for producing the carriers according to the invention. Furthermore, the method according to the invention for producing a carrier that can be loaded with aqueous media can be further developed into a method for producing a memory loaded with aqueous media. Another object of the invention is therefore achieved by a method for producing a storage medium loaded with an aqueous medium based on a hydrophobic polymer, comprising at least the steps of selecting a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 μm and an at least partially open-pore structure with an average pore diameter between 1 and 200 μm, hydrophilizing the polymer substrate present in particles on at least a part of its total surface, comprising the outer surface and the surface of its pores, and loading the hydrophilized polymer substrate present in particles with the aqueous medium up to a loading of 10 to 95% by weight, based on the total weight of the loaded storage, by contacting the hydrophilized polymer substrate with the aqueous medium.

Proceeding from the carrier according to the invention or by means of the method described above, according to the present invention, a storage medium consisting of particles and loaded with an aqueous medium is provided, which has a loading with the aqueous medium of 10 to 95% by weight, based on the Has total weight of the loaded storage, the particles being formed from a hydrophobic polymer substrate, having an average particle size between 50 and 5000 μm and having an at least partially open-pore structure and an average pore diameter between 1 μm and 200 μm.

The porous, particulate, hydrophobic polymer substrate used with an at least partially open-pored structure can have a sponge-like cellular structure or a network-like or coral-shaped microstructure. According to the invention, the pore structure must be at least partially open-pore, ie the pores present in the polymer substrate must be in fluid communication with one another at least in partial areas of the substrate structure, and the particles of the polymer substrate must be open-pore at least in partial areas of their outer surface. This allows sufficient permeability speed for aqueous media and the loading capacity with aqueous media required according to the invention. The use of a particulate polymer substrate with an at least partially open-pore structure and an average pore size between 1 μm and 200 μm on the one hand enables water or aqueous media to be taken up, and on the other hand allows the water or the aqueous to be fixed Medium in the pore system of the carrier according to the invention, so that it can best be used as a storage matrix according to the invention for aqueous media. In a preferred embodiment, the polymer substrate used according to the invention has an average pore diameter in the range between 5 and 100 μm. An average pore diameter in the range from 5 to 50 μm is particularly preferred. Carriers according to the invention based on polymer substrates with such preferred pore diameters show good loading properties and an excellent ability to store aqueous media without the aqueous medium escaping from the carrier.

The porous supports according to the invention in the form of particles are distinguished by a good absorption capacity for aqueous media. Here, the absorption capacity for aqueous media is assessed on the basis of the water absorption capacity when the carrier according to the invention is brought into contact with water, on the one hand with regard to the loadability so-called in the context of the present invention, i.e. the amount of water that can be taken up by the particulate porous carrier according to the invention, and on the other hand based on the characteristic loading time, i.e. the time it takes to fill the pore volume with water.

According to the invention, the particulate carrier has a loadability with water of 10 to 95% by weight, based on the total weight of the loaded carrier. In general, the greater the volume porosity of the polymer substrate used, the higher the loadability. The same applies also in relation to the loading of the memory according to the invention. For this purpose, the volume porosity of the polymer substrates used according to the invention is expediently between 15 and 95% by volume. In a preferred embodiment of the invention, the polymer substrate has a porosity in the range between 30 and 90% by volume. Carriers according to the invention based on such polymer substrates preferably have a loadability with water of between 25 and 90% by weight. A preferred memory based on such a polymer substrate has a loading in the range between 25 and 90% by weight. Polymer substrates with a porosity between 50 and 85% by volume are particularly preferred. Carriers according to the invention based on such particularly preferred polymer substrates preferably have a water loadability of between 45 and 85% by weight. Particularly with such carriers according to the invention, on the one hand a high loading capacity with water and on the other hand a high mechanical stability is realized, which enables problem-free storage of carriers filled with aqueous media, for example in containers or sacks, without the aqueous medium coming from the Particles emerges. A particularly preferred memory based on the particularly preferred polymer substrates mentioned has a loading with the aqueous medium in the range between 45 and 85% by weight.

In an advantageous embodiment, the particulate porous supports according to the invention have a characteristic loading time of at most 120 min and particularly preferably of at most 90 min.

In view of rapid loading and good pouring behavior of the carrier or of the storage according to the present invention, polymer substrates with a particle size between 50 and 5000 μm are preferred. Polymer substrates with a particle size between 400 and 3000 μm are particularly preferred. The particles of the polymer substrate and thus the particles of the carrier or memory according to the invention can have any shape exhibit. The particles of the polymer substrate can be spherical, oval, cylindrical, or granular or have any other regular or irregular shape.

For hydrophilization, the polymer substrate can, for example, be impregnated with a solution of a hydrophilic polymer. Suitable hydrophilic polymers are polymers such as, for example, polyethylene glycols, polyethylene oxides, polyacrylic amides, polyvinyl alcohols and the like. It is also possible to coat the surface of the polymer substrate with polymerizable hydrophilic monomers, a radical initiator and a crosslinking agent and to crosslink the monomer to form a hydrophilic layer on the surface.

However, surfactants are preferably used for the hydrophilization of the polymer substrate, i.e. In a preferred embodiment according to the invention, the porous polymer substrate is hydrophilized by being coated with a surfactant. Accordingly, the hydrophilization in the processes according to the invention preferably takes place in that the polymer substrate with a solution of a surfactant in a volatile solvent which is essentially inert to the polymer substrate and the polymer substrate is essentially non-solvent, at least in part of its total, the outer surfaces and the surface of its surface comprising pores is impregnated.

In the context of the present invention, surfactants are understood to mean substances whose molecules have at least one hydrophilic and one hydrophobic functional group, the hydrophilic and the hydrophobic parts of the molecules being in equilibrium with one another, as a result of which the molecules are able to separate from interfaces at aqueous surfaces Enrich phases. Furthermore, the surfactants have the ability to reduce the interfacial tension and to form so-called micelles. Advantageously in the context of the The present invention is that, because of the hydrophobic groups, the surfactants have a pronounced affinity for hydrophobic materials and so a good attachment of the surfactants to the surface of the porous hydrophobic polymer substrates used according to the invention and thus a good coating of the polymer substrates used according to the invention with the surfactants is possible. At the same time, the hydrophilic part of the surfactant molecules ensures the necessary pronounced affinity for aqueous media.

In the context of the present invention, a volatile solvent or solvent mixture is understood to mean such a solvent or solvent mixture whose boiling point is below the boiling point or the decomposition temperature of the surfactant used. The solvent or the solvent mixture preferably has a boiling point of at most 100 ° C.

According to the invention, the solvent or solvent mixture used to prepare the surfactant solution is one which is essentially inert to the polymer substrate, i.e. which does not substantially chemically react with the polymeric substrate and which does not substantially dissolve the polymeric substrate. In individual cases, however, a slight swelling of the polymer substrate under the influence of the solvent or the solvent mixture can be accepted.

For applications in which sufficiently stable coatings with good adhesion to the surfaces of the hydrophobic polymer substrate used are required in aqueous systems, the surfactants used are water-insoluble surfactants which are introduced into the polymer substrate by means of an organic solvent or solvent mixture. Of course, it is also possible, in accordance with the invention, to use water-soluble surfactants for hydrophilizing the polymer substrate. Here the porous carrier is directly impregnated with an aqueous surfactant solution.

At the same time, this results in a simple method for producing the memory according to the invention loaded with an aqueous medium based on a hydrophobic polymer, this method comprising the following steps: selection of a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 microns and has an at least partially open-pore structure with an average pore diameter between 1 and 200 microns, - direct loading of the hydrophobic polymer substrate with the aqueous medium up to a loading of 10 to 95 wt .-%, based on the total weight of the loaded storage , by contacting the hydrophobic polymer substrate with the aqueous medium, the aqueous medium containing a water-soluble surfactant.

The aqueous medium containing the water-soluble surfactant is thus left in the polymer substrate and a complex drying step to be interposed is eliminated. The loaded polymer substrate directly represents the memory according to the invention.

According to the invention, nonionic, anionic or cationic surfactants can be used for the hydrophilization.

If non-ionic surfactants are used, preference is given to those which are selected from the group of fatty acid glycerides, such as, for example, monoglycerides or diglycerides, and polyglycol ether surfactants, such as, for example, fatty alcohol polyglycol ether, alkylphenol polyglycol ether, fatty acid polyglycol ether, fatty acid amide polyglycol ethers, the fatty acid glycol esters, such as fatty acid ethylene glycol esters or fatty acid diethylene glycol esters, the fatty acid mono-, fatty acid di- or fatty acid triesters of sorbitan or fatty acid amides, such as fatty acid monoethanolamide or fatty acid diethanolamide. Mixtures of different surfactants can also be used. Fatty acid glycerides are particularly suitable, with particularly good results being achieved with glycerol monooleate or glycerol monostearate.

If water-soluble non-ionic surfactants are used according to the invention, an assessment of the water solubility is possible on the basis of the HLB value.

The HLB value (Hydrophilic Lipophilic Balance) expresses the ratio of the strength of the hydrophilic portion to the strength of the hydrophobic portion in the molecule. The HLB value is a measure of the water or oil solubility of predominantly nonionic surfactants and the stability of emulsions. The HLB value of a surfactant can be calculated additively from all molecular parts of the amphiphile. The type and number of the hydrophobic chain and the hydrophilic groups are involved. The scale generally ranges from 1 to 20. HLB values <7 characterize rather lipophilic molecules, which preferentially dissolve in the oil. As a rule, surfactants with HLB values of> 7 have sufficient solubility in water and can therefore be used as the water-soluble nonionic surfactants according to the invention. For the use of water-soluble nonionic surfactants, however, those with an HLB value between 10 and 15 are preferred.

In order to ensure that the non-ionic surfactant attaches well to the hydrophobic polymer, the hydrophobic part of the surfactant molecule should be composed of a chain of 10 to 30 carbon atoms. In a preferred embodiment, the hydrophobic part of the surfactant molecule consists of a chain of 10 to 20 carbon atoms. The sales Use of surfactant molecules in which the hydrophobic part consists of a chain of 10 to 15 carbon atoms. In the event of the use of water-soluble non-ionic surfactants, the HLB value should then be 10 to 15.

When using water-soluble surfactants, not only those from the group of non-ionic surfactants are to be used, but also ionic surfactants. The commercially available ionic surfactants, both anionic and cationic, are predominantly water-soluble.

Anionic surfactants with one or more functional anion-active groups dissociate in aqueous solution to form anions, which are ultimately responsible for the surface-active properties. Examples of typical anionic groups: -COONa, -SO ₃ Na, -OSO ₃ Na. Particularly suitable anionic surfactants are those selected from the group of soaps, alkyl sulfates, alkane sulfonates, alkyl arene sulfonates (eg dodecylbenzenesulfonate) or alkylbenzenesulfonates, α-olefin sulfonates, fatty alcohol sulfonates, fatty alcohol ether sulfonates or succinate sulfonates or dialkyl sulfates.

In the case of cationic surfactants, the high-molecular hydrophobic residue which causes the surface activity is in the cation during dissociation in aqueous solution. Cationic surfactants used with success are quaternary ammonium compounds of the general formula: (R ₄ N ⁺ ) X ^" . These preferably include dimethyldisterylammonium chloride, trimethylpalmitylammonium chloride or dimethylcocbenbenzylammonium chloride.

It is advantageous if the concentration of the surfactant in the particulate carrier according to the invention or in the storage matrix according to the invention is between 0.1 and 15% by weight and particularly preferably between 1 and 10% by weight. Very good results are achieved if the concentration between 3 and is 10% by weight. The concentration is to be chosen as a function of the porosity of the porous polymer substrate used so that sufficient hydrophilization is achieved on the one hand and blocking, ie clogging of the pores by the coating with the surfactant, is avoided on the other hand. The hydrophilized polymer substrate and thus the carrier according to the invention preferably have the same porous configuration as the uncoated polymer substrate. The hydrophilization is therefore preferably carried out in such a way that the porous structure of the polymer substrate is essentially not changed by the hydrophilization, ie there is no clogging of the pores of the polymer substrate. To produce the carrier according to the invention or the memory according to the invention with a suitable concentration of surfactant, the concentration of the surfactant in the solution is preferably 1 to 10% by weight in the methods according to the invention.

An organic solvent or solvent mixture is expediently used to wet the polymer substrate used with the surfactant solution, in particular if water-insoluble surfactants are used to prepare the surfactant solution. If water-soluble surfactants are used to prepare the surfactant solution, water is expediently used as the solvent.

An organic solvent or solvent mixture is also to be understood as meaning one which contains portions of water, as long as the production of a homogeneous solution of the surfactants used is below the boiling point of the solvent or solvent mixture, preferably at temperatures in the range between 60 ° C. and 70 ° C. is possible and the polymer substrate is well wetted by the solution, so that the polymer substrate can be impregnated with the surfactant solution. The organic solvent or solvent mixture is particularly preferably selected from the group of alcohols, ketones or esters or from mixtures of these substances. According to that Alcohol / water mixtures, for example, can also be used.

Various procedures are available for impregnating the polymer substrate with the solution of the surfactant. A preferred procedure consists in immersing the polymer substrate in the surfactant solution for a sufficiently long period of time in order to impregnate the entire surface that can be achieved. An ultrasonic bath can also be used to support the impregnation process, or a vacuum can also be applied.

To remove the solvent or solvent mixture used to produce the carrier according to the invention, the polymer substrate is dried after impregnation with the surfactant solution. This can be done under elevated temperatures and / or under vacuum. The drying temperatures should be chosen so that the surfactant does not evaporate and does not decompose. Dielectric drying e.g. using microwaves is possible.

According to the invention, preference is given to using hydrophobic polymer substrates which are composed of polymers or mixtures of polymers from the group of the polyolefins, the fluoropolymers, the styrene polymers or a copolymer of these polymers. Polyolefins which can be used particularly advantageously are polyethylene, ie HDPE, LDPE, LLDPE or UHMW-PE, polypropylene, poly (4-methyl-1-pentene), poly (l-butenes) or polyisobutene, and as copolymers ethylene-propylene copolymer or ethylene vinyl acetate copolymer. Particularly preferred fluoropolymers are polyvinylidene fluoride and polyvinyl fluoride and the copolymers poly (tetrafluoroethylene-co-hexafluoropropylene), poly (tetrafluoroethylene-co-perfluoroalkyl vinyl ether) and poly (ethylene-co-tetrafluoroethylene). Particularly suitable as styrene polymers are polystyrene and Styrene-acrylonitrile copolymers, styrene-butadiene copolymers and acrylonitrile-butadiene-styrene copolymers. Polymer substrates based on polyolefins and in particular based on polypropylene or polyethylene are particularly preferred.

The polymers or mixtures of polymers that make up the hydrophobic polymer substrates can contain additives such as e.g. Contain antioxidants, nucleating agents, fillers, UV absorbers and the like in order to modify the properties of the substrates in a targeted manner. The concentration of such additives is usually less than 10% by weight and preferably less than 2% by weight.

The particulate polymeric carriers for aqueous media according to the invention can best be used to produce polymer particles loaded with aqueous media, i.e. use for the production of a storage for aqueous media. For example, Polymer structures are produced that contain a high proportion of water and that are used for applications such as the foaming of thermoplastic polymers or as a substrate for air conditioning and / or moisture regulation of air can be used. The production of masterbatches with additives, e.g. is initially available as a dispersion, is easily possible by means of the particulate polymeric carrier according to the invention by first filling a particulate polymeric carrier with a sufficient amount of the aqueous dispersion and then removing the water content by drying. As a result, the solids content remains in the pore structure.

The invention will be explained in more detail using the following exemplary embodiments. The following methods of characterization were used in these examples: Determining the particle size:

The average particle size is determined microscopically on the basis of a representative sample quantity using a measuring eyepiece or using a suitable image evaluation method.

Determination of the average pore size:

The average pore size is made using digitized SEM images of fracture images of the samples, which are evaluated using suitable image analysis software. The pore diameter of approx. 50 to 100 pores in μm is measured from a SEM image. The associated mean pore diameter is calculated from the individual values by averaging.

Determination of volume porosity:

Methods known per se can be used to determine the volume potential. A pycnometric measurement method using water as the non-wetting liquid is suitable for determining the volume porosity of the hydrophobic polymer substrate. Furthermore, the volume porosity can be carried out using suitable intrusion methods such as via mercury intrusion or intrusion of other suitable liquids.

Determining the loadability and the characteristic loading time: The determination of the loadability and the characteristic loading time presupposes that the volume porosity of the material to be examined is known.

Approx. 10 to 30 g of the material to be examined are weighed into a 500 ml glass flask. The amount of water added to the sample material is to be added, ie the volume of water to be added, is determined by the porosity of the sample material or by the pore volume of the weighed sample material. The pore volume of the sample material can be determined from the sample weight, the polymer density ppoiymer and the porosity ε. In the first step, enough water is metered in that a complete absorption of the water by the sample material can be expected. For this purpose, a water volume is added which corresponds to approx. 60% of the determined pore volume of the sample.

After the addition, the glass flask is mixed with a suitable mixing device, e.g. connected to a rotary evaporator with a water bath heated to 25 ° C. Then mix until the sample material is dry on the outside and free-flowing. The loading time from the start of mixing to the complete absorption of the water is determined with a stopwatch.

The glass bulb is then removed from the mixing device and a further amount of water is added, which corresponds to 5% of the pore volume. The mixture is then mixed again and again the time is stopped until this amount of water has also been completely absorbed by the sample. This process is repeated until the sample material is saturated with water, with an amount of water being added that corresponds to 5% of the pore volume. The saturation is defined as the state in which water is still observed on the wall of the glass bulb and / or the particles of the sample material stick together even after a total loading time of 3 hours. The characteristic loading time is the sum of the individual loading times determined by means of a stopwatch, for which a complete absorption of the amount of water from the sample took place. The saturated sample material is then Weighed back and determined the total amount of water absorbed by the sample material from the difference with the weight.

The loadability of the carrier results from the ratio of the total amount of water taken up by the sample material and the weight of the saturated sample material in percent.

Example 1:

A particulate porous polymer substrate made of polypropylene in the form of granules with a porosity of 78 vol.%, An average pore size of 20 μm and an average particle size of 3 mm × 3 mm was used. This polymer substrate was loaded with a 5% by weight solution of the nonionic surfactant Synperonic PE / L 121, a copolymer of a polyethylene glycol and a polypropylene glycol (Uniqema), in isopropanol. The amount of surfactant solution and thus the amount of surfactant were measured so that after drying the treated polymer substrate a particulate carrier with a concentration of the surfactant of 5% by weight was obtained. At this surfactant concentration, the hydrophilized polymer substrate had essentially the same porous configuration as the starting hydrophobic polymer substrate.

The particulate porous carrier coated with the surfactant showed a loadability with water of 50% by weight, based on the total weight of the loaded carrier, and a characteristic loading time of 90 min. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 50% by weight based on the total weight. Example 2:

The same porous polymer substrate as in Example 1 was used. 15 g of the polymer substrate were loaded with 45 g of a 5% by weight solution of the non-ionic surfactant Synperonic PE / L 121 in isopropanol for one hour. After drying by means of vacuum in a water bath heated to 70 ° C., a surfactant content of 13% by weight was obtained.

The dried, particulate porous carrier coated with the surfactant showed a loadability with water of 60% by weight, based on the total weight of the loaded carrier, and a characteristic loading time of 75 min. The carrier thus loaded simultaneously represents the storage according to the invention with a loading of 60% by weight based on the total weight.

Example 3:

The same porous polymer substrate as in Example 1 was used. The polymer substrate was coated with the anionic surfactant AEROSOL ^® MA; coated (Fa Cy ~ tec sodium di (1, 3-dimethylbutyl) sulfosuccinate.)) To give procedure as in Example 1. Coated with the AEROSOL ^® MA particulate porous carrier showed a loading capacity with water of 60 wt .-%, based on the total weight of loaded support, and min is a characteristic loading time of 5 avg. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 60% by weight, based on the total weight.

Example 4:

A microporous HDPE granulate with a porosity of 65 vol.%, An average pore size of 15 μm and an average particle size of 3 mm × 3 mm was used as the porous particulate polymer substrate. The HDPE polymer substrate was coated on its pore surface and on its outer surface according to the procedure outlined in Example 1 with 5% by weight glycerol monooleate. Thus, the hydrophilized polymer substrate coated with glycerol monooleate also had essentially the same porous configuration as the starting hydrophobic polymer substrate.

The particulate porous carrier obtained had a water loadability of 60% by weight, based on the total weight of the loaded carrier, and a characteristic loading time of 100 minutes. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 60% by weight, based on the total weight.

Example 5:

The same porous polymer substrate as in Example 4 was used. This polymer substrate was also loaded with a 5% by weight solution of glycerol monooleate in isopropanol. Here, 18 g of the polymer substrate were loaded with 42 g of the surfactant solution for one hour, so that after Drying by means of vacuum in a water bath heated to 70 ° C. a surfactant content of 10.4% by weight was obtained.

The particulate porous carrier coated with the surfactant showed a water loadability of 65% by weight, based on the total weight of the loaded carrier, and a characteristic loading time of 90 min. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 65% by weight based on the total weight.

Example 6:

The same HDPE polymer substrate was used as in Example 3, which was coated on its pore surface and on its outer surface according to the procedure outlined in Example 1 with the non-ionic surfactant ^Span® 80 (sorbitan monooleate; Merck).

A porous support with a water loadability of 50% by weight, based on the total weight of the loaded support, and a characteristic loading time of 60 minutes was obtained. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 50% by weight based on the total weight.

Example 7:

The HDPE granulate also used in Example 4 was used as the particulate polymer substrate. This polymer substrate was covered with a 5th Load the% by weight solution of the non-ionic surfactant Span ^® 80 in isopropanol. Here, 18 g of the polymer substrate were loaded with 42 g of the surfactant solution for one hour. After drying by means of vacuum in a water bath heated to 70 ° C., a surfactant content of 10.4% by weight was obtained.

The dried, particulate porous carrier coated with the surfactant showed a loadability with water of 65% by weight, based on the total weight of the loaded carrier, and a characteristic loading time of 120 min. The carrier thus loaded simultaneously represents the store according to the invention with a loading of 65% by weight based on the total weight.

Example 8 -

The same porous particulate polymer substrate as used in Examples 4-7 was used. This polymeric substrate was impregnated with the water-soluble anionic surfactant ARMA (sodium di (1,3-dimethylbutyl) sulphosuccinate, CYTEC Industries Inc., USA). An aqueous surfactant solution with a surfactant content of 5% by weight was used. 20 g of the polymer substrate were loaded with 30 g of the surfactant solution. This product was a particulate memory loaded with 60% by weight (based on the total weight) of an aqueous medium.

The particulate polymer substrate loaded with the aqueous surfactant solution was then dried to examine water reloadability. The dried, porous particulate carrier coated with the surfactant showed a loadability with water of 60% by weight, based on the total weight of the loaded carrier and a characteristic loading time of 35 minutes. The loaded carrier in turn represents the storage according to the invention with a loading of 60% by weight based on the total weight.

Comparative Example 1:

The polypropylene substrate used in Example 1 was examined for its loadability with water without further treatment. For this purpose, only a water volume was initially added which corresponded to approximately 10% of the determined pore volume of the sample. Even after 3 hours the sample material was still not dry on the outside, i.e. it hadn't taken up any water. The untreated polypropylene substrate showed no water loading.

Claims

claims:

1. Carrier in the form of particles which can be loaded with aqueous media, the particles being formed from a porous hydrophobic polymer substrate, having an average particle size between 50 μm and 5000 μm and having an at least partially open-pore structure with an average pore diameter between 1 μm and 200 μm and wherein the particulate carrier has a loadability with water, determined by contacting with water, from 10% by weight to 95% by weight, based on the total weight of the loaded carrier.

2. Carrier according to claim 1, characterized in that the porous polymer substrate is hydrophilized on at least a part of its entire surface comprising the outer surfaces and the surface of its pores.

3. Carrier according to one or both of claims 1 or 2, characterized in that the porous polymer substrate is hydrophilized on substantially its entire surface, the outer surfaces and the surface of its pores.

4. Carrier according to one or both of claims 2 or 3, characterized in that the porous polymer substrate is hydrophilized by coating with a surfactant.

5. Carrier according to claim 4, characterized in that the surfactant is a non-ionic surfactant selected from the group of fatty acid glycerides, polyglycol ethers, fatty acid glycol esters, fatty acid mono-, fatty acid di- and fatty acid triesters of sorbitan or of fatty acid amides.

6. A carrier according to claim 5, characterized in that the non-ionic surfactant is a fatty acid glyceride.

7. A carrier according to claim 5, characterized in that the non-ionic surfactant has an HLB value greater than 7.

8. A carrier according to claim 5, characterized in that the non-ionic surfactant has an HLB value of 10 to 15.

9. A carrier according to claim 4, characterized in that the surfactant is an anionic surfactant, selected from the group of soaps, the alkyl sulfates, the alkane sulfonates, the alkyl arene sulfonates or the alkyl benzene sulfonates, the α-olefin sulfonates, the fatty alcohol sulfonates, the fatty alcohol ether sulfonates or the dialkyl sulfosuccinates.

10. A carrier according to claim 4, characterized in that the surfactant is a cationic surfactant selected from the group of quaternary ammonium compounds.

11. A carrier according to one or more of claims 4 to 10, characterized in that the concentration of the surfactant in the carrier is between 0.1 and 15 wt .-%, based on the weight of the carrier.

12. Carrier according to one or more of claims 1 to 11, characterized in that the polymer from which the polymer substrate is constructed is a polyolefin, a fluoropolymer or a styrene polymer or a copolymer of these polymers.

13. A carrier according to one or more of claims 1 to 12, characterized in that it has essentially the same porous configuration as the porous polymer substrate.

14. Carrier according to one or more of claims 1 to 13, characterized in that the porosity in the range between 30 and 90 vol .-% and the loadability with water between 25 wt .-% and 90 wt .-%, based on the Total weight of the loaded carrier.

15. A carrier according to one or more of claims 1 to 14, characterized in that the particles have an average pore diameter in the range between 5 microns and 100 microns.

16. A carrier according to one or more of claims 1 to 15, characterized in that it has a characteristic loading time for water of at most 120 min.

17. Carrier according to one or more of claims 1 to 15, characterized in that it has a characteristic loading time for water of at most 90 min.

18. A method for producing a carrier which can be loaded with aqueous media in the form of particles based on a hydrophobic polymer, the carrier having a loadability with water, determined by contacting it with Water, from 10 to 95 wt .-%, based on the total weight of the loaded carrier, comprising the following steps: - Selection of a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 μm and at least one partially open-pore structure with an average pore diameter between 1 μm and 200 μm, - hydrophilizing the polymer substrate present in particles on at least a part of its entire surface, comprising the outer surface and the surface of its pores, in order to obtain the carrier which can be loaded with aqueous media ,

19. The method according to claim 18, characterized in that the carrier which can be loaded with aqueous media has essentially the same porous configuration as the hydrophobic polymer substrate.

20. The method according to claim 18 or 19, characterized in that the polymer substrate for hydrophilization with a solution of a surfactant in a volatile, substantially inert to the polymer substrate and the polymer substrate essentially non-solvent or solvent mixture at least in part of its total , the outer surface and the surface of its surface comprising pores is impregnated.

21. The method according to claim 20, characterized in that the solvent or the solvent mixture has a boiling point of at most 100 ° C.

22. The method according to one or both of claims 20 or 21, characterized in that an organic solvent or solvent mixture is used as the solvent or solvent mixture.

23. The method according to claim 22, characterized in that the solvent or the solvent mixture is selected from the group of alcohols, ketones or esters.

24. The method according to one or more of claims 20 to 23, characterized in that a nonionic surfactant selected from the group of fatty acid glycerides is used for the hydrophilization.

25. The method according to one or both of claims 20 or 21, characterized in that water is used as solvent.

26. The method according to claim 25, characterized in that a water-soluble, non-ionic surfactant with an HLB value greater than 7 is used as the surfactant.

27. The method according to one or more of claims 20 to 26, characterized in that the concentration of the surfactant in the solution is 1 to 10 wt .-%.

28. The method according to one or more of claims 18 to 27, characterized in that the polymer substrate is composed of a polyolefin, a fluoropolymer, a styrene polymer or a copolymer of these polymers.

29. The method according to one or more of claims 18 to 28, characterized in that the polymer substrate has an average pore diameter in the range between 5 and 100 microns.

30. The method according to one or more of claims 18 to 29, characterized in that the polymer substrate has a volume porosity between 30 and 90 vol .-%.

31. A method for producing a storage medium loaded with an aqueous medium based on a hydrophobic polymer, comprising at least the steps: - the selection of a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 μm and at least partially having an open-pore structure with an average pore diameter between 1 and 200 μm, - hydrophilizing the polymer substrate present in particles on at least part of its entire surface, comprising the outer surface and the surface of its pores, and - loading the hydrophilized polymer substrate present in particles with the aqueous medium up to a loading of 10 to 95% by weight, based on the total weight of the loaded storage, by contacting the hydrophilized polymer substrate with the aqueous medium.

32. A method for producing a storage medium loaded with an aqueous medium based on a hydrophobic polymer, comprising at least the steps: - the selection of a porous hydrophobic polymer substrate in the form of particles, the polymer substrate having an average particle size between 50 and 5000 μm and at least partially Open-pore structure with an average pore diameter between 1 and 200 microns, - the direct loading of the hydrophobic polymer substrate with the aqueous medium up to a loading of 10 to 95 wt .-%, based on the total weight of the loaded storage, by contacting the hydrophobic polymer substrate with the aqueous medium, wherein the aqueous medium contains a water-soluble surfactant.

33. A storage medium loaded with an aqueous medium and consisting of particles with a loading with aqueous medium of 10 to 95% by weight, based on the total weight of the loaded storage, the particles being formed from a hydrophobic polymer substrate, an average particle size between 50 and 5000 μm and have an at least partially open-pore structure and an average pore diameter between 1 μm and 200 μm.