DE10062558A1 - Removal of malodorous gases and liquids, useful for odor absorbers in hygienic products, e.g. sanitary towels or underarm protectors, comprises adsorption on porous silicic acid or metal silicate having narrow mesopore radius distribution - Google Patents

Abstract

Removal of malodors from environments containing gases and liquids, by adsorption of the malodorous components on porous silicic acids or metal silicates, comprises using silicic acids/silicates (I) which have a uniform mesopore diameter or a narrow mesopore radius distribution. Independent claims are included for: (1) Hygienic articles containing (I); (2) Disposable adsorbent articles for collecting liquid from a source and eliminating malodors from the absorbed liquid, comprising: (a) an adsorbent core for absorbing the liquid; (b) a liquid-impermeable backing sheet; (c) a liquid-permeable covering sheet; and (d) (I) as adsorbent for malodorous components; and (3) Polymers free of (or having reduced) odor, which contain (I) having a narrow mesopore radius distribution.

Description

The present invention relates to a method, smells from gaseous and liquid environments to remove by adsorption. In addition, the Invention the application of the method described in hygiene neartikeln.

We can classify smells as positive, negative or neutral estimate. For example, most people feel that Fragrance of freshly ground coffee as very pleasant, even if you don't like the drink yourself. Other smells, like sweat, for example, is taken as was uncomfortable. Odors are caused by chemical Substances that, to be perceivable by humans, more or less volatile.

There are three basic principles for odor control opportunities. The first method is unan pleasant to cover with pleasant smells. Another As far as possible, the method is the emergence of bad to prevent smelling substances. Both methods will be used together in deodorant sprays, for example, in which on the one hand an antiperspirant and on the other hand a Perfume is included.

The most common method, however, is less wanted odorants in a non-volatile form convict, and thus not the human sense of smell to make it more accessible. This can be done, for example a chemical reaction or by adsorption, however, in some cases it is not clear whether it is the adsorption is a chemical, physical or is a combined process.

A commonly used odorant adsorbent is Koh lenstoff, for example in the form of activated carbon. Adsor Carbon-based bentien have the possibility that they  over a wide range of substance classes cause substances to adsorb. However, you have that Disadvantage that due to their black color in many areas cannot be used. Another The disadvantage is that carbon adsorbents are easily flammable, and therefore always a potential Ge represent driving.

Carbonates, silica gels, aluminum oxides, diatomaceous earth, clays and Zeolites are also used as an adsorbent for odorants used. However, these have odor reducing agents the disadvantage that they only have a relatively small spectrum Can adsorb odorants permanently. This can be done the structure of the adsorbents, for example in Zeo lithen, or because the character of the adsorbents rather is acidic or alkaline. Another disadvantage is in that these substances have low concentrations of Odorants not or only very poorly adsorbate can. This disadvantage is significant because of many Odor substances are still evident even at low concentrations be perceived.

Odor-absorbing substances are used in many areas set. Often the smells are not only caused by one Substance caused but by a complex mixture of substances with a wide variety of chemical and physical substances properties. Smells, for example, by human excretions are created by a com complex mixture of fatty acids, amines, aldehydes, mercapta and other connections. You can't Using adsorbents made of coal, mixtures are made different means of odor control used to adsorb these common compounds together to be able to. According to document EP 0811387 a Ge mix of zeolites and silica gel for odor adsorption used. Has the use of an adsorbent mixture the disadvantage of a significantly greater effort in the manufacture  position and application of the odor-reducing agents. Au It is also possible that the different odors sorbents in a negative way with each other inter act.

According to document US 4,795,482, crystalline zeolites with a molar Si / Al ratio greater than 35 be wrote of odorants of different chemical Can adsorb substance classes. Have these zeolites but the disadvantage that they have a very complex, energy and raw material consuming process the. Therefore, these zeolites are only used to a limited extent turn. Another disadvantage is that the be wrote zeolites mostly only micropores with one Pore radius less than about 1.5 nm. This allows Odorants with more sterically demanding molecules cannot be adsorbed.

The object of the invention is to develop a new method for ver to develop odor reduction. In this process means are to be used, the odoriferous substances from un Different substance classes, even in low concentrations ions adsorb equally well and permanently, one have a good appearance from an aesthetic point of view and are not flammable. In addition, the adsorption medium light and with low energy and raw material consumption wall and be inexpensive.

Surprisingly, it has been found that certain porous Silica and metal silicate odor-producing compound different substance classes even with low Adsorb concentrations effectively and permanently. In order to they are excellent as a deodorant. You under differ from those previously used to adsorb odor substances used silicas and silicates in that they to a large extent mesopores with uniform meso pore diameters or with a narrow mesopo have a radius distribution. Mesoporous silicas  and silicates are simple and with relatively low energy and raw material costs and are due to their chemical composition not flammable. The procedure for the adsorption of odors on this mesoporous silica Ren and metal silicates can different areas be applied.

The invention relates to a method for removal unwanted odors from gaseous and liquids containing environments by adsorbing the olfactory substances on porous silicas or metal silicas katen, characterized in that the silicas or Metal silicates have a uniform mesopore diameter or a narrow mesopore radius distribution sen.

The invention further comprises hygiene articles in which porous silicas or metal silicates are contained, which are characterized in that the silicas or metal silicates have a uniform mesopore diameter or a narrow mesopore radius distribution exhibit.

Furthermore, the invention largely includes odorless Plastics in which porous silicas or metal silicas kate are included, which are characterized by that the silicas or metal silicates have a uniform chen mesopore diameter or a narrow mesopo have a radius distribution.

From the literature it is known that solids on silicon dioxide base for separating organic compounds be used. In addition to silica gel, these include, for example also zeolites, which in addition to silicon dioxide also contain aluminum oxides and can contain metal ions. Zeolites are in the Literature often referred to as molecular sieve because they have regular pores with defined pore radii. This enables the separation of substances accordingly  their size, or in other words the steric The claim of the molecules: Smaller molecules can enter the bottom penetrate and can be adsorbed there, larger ones Molecules don't. A corresponding principle is from known to some silicates. With the silicon described Oxide compounds can thus be chemical substances separate according to their molecular size. With this me Compounds that are chemically and are physically very similar, but differ in the steric Differentiate claim of their molecules.

Another separation principle, for example with silica gel in the different chemical and physical Exploit properties of different substances. For example, connections with different Different polarity or acidity on the jaw self-adsorbed, so that the sub punching are to be separated.

So there is a separation of different substances by possible that the release agent used, for play zeolites or silica gel, these substances under well adsorbed.

In most cases, smells are complex Mixture of different substances generated. smells, which arises, for example, from human excretions hen, through a complex mixture of fatty acids, Amines, aldehydes, mercaptans and other compounds are caused. In contrast to that as a release agent The adsorbents used are the task of odor adsorbers need, if possible, all odor-causing substances adsorb equally well.

The invention shows that mesoporous silicas and Me tall silicates with a uniform mesopore diameter or a narrow mesopore radius distribution, such as they are, for example, in document DE 198 41 142.1  a surprising number of chemically and physically different substances adsorb well and permanently. Therefore, they are less than Release agent, but very good as an odor adsorbent bar.

According to the invention, pores with diameters between 2.0 and 30 nm as mesopores, pores with diameters smaller than 2.0 nm as micropores and pores with diameters larger than 30 nm referred to as macropores.

Under chemically and physically different substances In this context, zen are substances with under different functional groups and different Understood size. These substances can be acidic compounds gene, caused for example by in the molecule contained carboxyl groups. You can also use a basic verb such as amines, or neutral compounds like mercaptans. Due to the different The functional groups differ in the substances not only in their acidity, but also in others, properties important for adsorption such as wise of their polarity.

Examples of odor-producing substances that according to the processes according to the invention can be adsorbed Acetic acid, propionic acid, butyric acid, γ- Hydroxybutyric acid, valeric acid, isovaleric acid, Ca. pronic acid, caprylic acid. Isobutyraldehyde, methyl mercaptan, Ethyl mercaptan, propyl mercaptan, allyl mercaptan, isoamyl mercaptan, n-butyl mercaptan, crotyl mercaptan, propanethiol, Thiophenol, o-methylthiophenol, allyl disulfide, allyl sulfide, Diallyl sulfide, amyl sulfide, benzyl sulfide, thiocresol, thioi sobutylaldehyde, thioisovaleraldehyde, γ- Hydroxypropylmethyl sulfide, β, β'-dichlorovinyl sulfide, dime ethyl tetrasulfide, ethylenediamine, methylamine, trimethylamine, Triethylamine, allylamine, 3-methylindole, 4-methylindole, 7-  Methyl indole, β- (indolyl-3) propionic acid, d-amino-β- (indolyl-3) propionic acid and indole acetic acid.

Processes for the production of porous silicas and metal silicates produced by precipitation have already been comprehensively described, for example, in DE 198 41 142.1. The preferred embodiments of the method together comprise the following steps (variant A)
Preparation of a mixture consisting of water, optionally a metal silicate solution and a surfactant (template),
Precipitation: Simultaneously adding a metal silicate solution and an acid to the stirred mixture from (1), which had previously been brought to a certain temperature,
optionally aging of the reaction mixture,
Separation, optionally washing and drying of the solid formed in (2),
Optional: removal of the surfactant by extraction and / or thermal treatment.

Any silicate solution may be preferred as the metal silicate solution Alkali silicate solution, especially sodium silicate solution (Water glass solution).

The manufacturing process according to variant A from DE 198 41 142.1 can be modified as follows (variants B and C):

Preparation of a mixture of water, metal silicate solution and surfactant (variant B) or a mixture of Water, acid solution and a surfactant (variant C) in the Seal pot.

Add an acid solution (variant B) or one Metal silicate solution (variant C) to the stirred mixture from (1), previously brought to a certain temperature has been.  

Steps (3) to (5) are essentially the same as for Va Riante A described.

Cationic, nonionic or anionic can be used as surfactants cal surfactants in different concentrations be set. Nonionic surfactants are preferred Polyethylene oxide base, for example ethoxylated alcohols or alkylphenols. More in question non-ionic and ionic surfactants are described in DE 198 41 142.1 or in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, volume 25A, p. 751 (1994). The choice of a certain surfactant is u. a. dependent of solubility, miscibility or disper yawability in water in the desired concentration, pH and temperature range.

The precipitation parameters in step (2) of the manufacturing process, especially the total amount and concentration used the metal silicate solution and the acid solution, the inlet speed, the pH before and during the precipitation, the Felling time, the falling temperature and the type and intensity the stirring during the precipitation are preferred in the range from known standard silica precipitation (for example EP 0 789 266), but can be used within the chemical, limits that can be achieved physically and in terms of apparatus vary become.

When using nonionic surfactants, the Me tall silicate and acid solution are metered in such a way that the pH of the reaction mixture during the precipitation between 2 and 8, but preferably between 5 and 7. to finally the pH can be adjusted by adding more acid ter be lowered. The optimal fall temperature can be between 20 and 70 ° C, preferably between 30 and 50 ° C.

A sodium water glass with a modulus of 3.4-3.5, an SiO ₂ content of 26.6-27.0% and an Na ₂ O content of 7.8-8.2% can preferably be used. As acids, for example, sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid or formic acid can be used. Sulfuric or hydrochloric acid can preferably be used.

The total amount of the metal silicate and acid solution can be chosen so that the molar surfactant / SiO ₂ ratio after the addition of the starting materials is between 0.01 and 2.0, preferably between 0.1 and 1.0 and particularly preferably between 0.15 and 0.5.

Metal silicates, such as calcium silicates, boro-, Aluminum, manganese, iron or titanium silicates can be used be made by adding suitable metal salts in (1) to the water / surfactant mixture or in (2) with the Metal silicate and acid solution added. The acid used can be partially or completely omitted. Salts of elements B, Al, Ga, Ge, Sn, Ti, Zr, V, Cr, Mo, W, Fe, Co, Ni or Zn included be set.

After complete addition of the metal silicate, acid and if necessary, metal salt solution, the resulting Sus Pension in step (3) at a temperature of 0 ° C to 100 ° C, preferably between room temperature and the precipitation temperature, optionally aged with stirring, wherein 12 hours are generally sufficient.

The solid formed in (4) can be separated off before preferably by filtration, for example by means of chamber, Membrane filter press, band filter, rotary filter or a com combination of these filters. For drying a Um barrel, floor, flash, spin flash, current dryer or any the other suitable drying unit can be used.

The filter cake can after its viscosity has decreased was set in a spray dryer with or without inte Fluidized bed using atomizer, single-component nozzle or  Two-substance nozzle are atomized and dried. Likewise Fluid bed drying is possible. The filter cake can also be done without changing the viscosity be subjected to mill drying.

More detailed descriptions of the manufacture of the for the Mesoporous oxides used according to the method of the invention can be found a. in document DE 198 41 142.1.

In the described way you can use porous silicas and Metal silicates with a pore diameter between 2 and 30 nm received, according to the invention for permanent adsorption of odor-producing substances are used.

Porous silicas and metal silicates are preferred an average pore diameter between 2 and 10 nm, yet more preferably between 2 and 5 nm for odor adsorption applies. The average pore diameter is according to the Formula 4V / A calculated, where V is the accumulated volume of Pores between 2 and 10 nm and A the accumulated surface the pore is between 2 and 10 nm. The middle pores diameter can in the production described by the choice of surfactant can be adjusted, the length the longest C chain is of particular importance.

The materials for the process according to the invention for adsorbing odorous substances also have a narrow mesopore radius distribution. This can be seen from a generally pronounced level in the N ₂ ad and de sorption isotherms. The narrow mesopore radius distribution is expressed in the small half-width of the pore radius distribution curve. The full width at half maximum of the pore radius distribution is less than 5 nm, preferably less than 3 nm, depending on the size of the average pore diameter.

The pebbles used for the process according to the invention Acids and metal silicates can preferably be amorphous  it says there are no long-range orders within the festival fabric. The absence of crystalline phases, that is the lack of long-range order can be caused by the transmission elec tron microscopy (TEM), X-ray powder diffractometry and Electron diffraction can be detected. The materials are preferably completely X-ray amorphous or only one wide reflex - due to the uniform pore diameter sers - observed in the small angle scattering range. Bragg reflections higher order are not observed. An electron Diffraction provides only one or more wide diffraction rings ge. This means that the materials are not a long-range order exhibit. X-ray powder diffractograms and TEM images of the materials used in the invention can for example, taken from document DE 198 41 142.1 the.

The mesopore volumes of the silicas and metal silicates used according to the invention can be greater than 0.5 ml / g, in many cases even greater than 0.8 ml / g. The mesopore volumes are determined by means of N ₂ sorption according to the BJH method (DIN 66134). The materials used according to the invention have no or only a few micropores. The macroporous volumes of the powdery, undeformed materials, in general intermediate particle volumes, can be more than 2.5 ml / g, often even up to 5.0 ml / g. The macro pore volume for pores over 30 nm is determined by means of mercury porosimetry in accordance with DIN 66133. The total pore volume results from the sum of the mesopore and macroporous volume. It can be greater than 3.0 ml / g.

The porous silicas and metal silicates used for the process according to the invention can have specific surface areas greater than 500 m ² / g, generally even greater than 700 m ² / g. The specific surface is determined by N ₂ adsorption using the BET method (DIN 66131).

The silanol group density of the silicas and metal silicates used according to the invention can be less than 3 OH groups per nm ² , preferably less than 2 OH groups per nm ² . The silanol group density is measured by volumetric determination of the hydrogen formed when a material dried at 120 ° C. (drying time approx. 1 h) is reacted with LiAlH ₄ in diethylene glycol dimethyl ether and is related to the specific surface (series of pigments, basics of Aerosil® , No. 11, Degus sa AG).

The mesoporous silicas and Metal silicates before use in the invention Process thermally treated. In this way u. a. ensures that the necessary in the manufacture Surfactants are completely removed from the material, and so the pores free for the adsorption of odor-producing Are substances. To do this, the product is at a temperature between 150 and 900 ° C, preferably between 300 and 600 ° C annealed in an inert gas or air atmosphere. By this treatment also makes the material sticky Free water. The duration of the thermal treatment can preferably 30 minutes to 12 hours. A longer anneal however, does not adversely affect the product.

The SiO ₂ content of the silicas used according to the invention can be at least 95% by weight, preferably over 98% by weight, based on the dry substance of the powder. The metal oxide content (MeO, where Me = alkali or alkaline earth metal, preferably Na, K or Ca) can be between 0.0001 and 5.0% by weight, preferably between 0.1 and 1.0% by weight , The metal silicates can contain one or more metal oxides or semimetal oxides. It can be metal or semi-metals from the 1st to 5th Main group or 2nd-8th Act subgroup. Metal oxides of the metals from the series B, Al, Ga, Ge, Sn, Ti, Zr, V, Cr, Mo, W, Mn, Fe, Co, Ni or Zn are preferred.

In the composition of the metal silicates used according to the invention, the ratio SiO ₂ to metal oxide SiO ₂ / [M _m O _n ] = 5-10. 000 mol / mol, preferably 10-100 mol / mol, and particularly preferably 20-60 mol / mol, where [M _m O _n ] is the sum of the mol numbers of all metal oxides contained M _m O _n . The SiO ₂ content is then correspondingly lower, based on the dry substance of the powder.

Mesoporous silicas and metal silicates for adsorp tion of smells can be preferred in the form as they accrued as powder according to the process described above, can be used as an odor adsorbent. You can before Further processed as an odor adsorbent the. The mesoporous silicas and metal silicates can also in other forms, for example as aerosol or Monolit can be used for odor adsorption. It is possible to posi the materials directly in an environment tion in which the odoriferous substances contain are or it is possible to remove the odorants holding current through the basis of this invention to manage the relevant adsorbent. So far, the after Apparatus known from the prior art can be used those for odor reduction by adsorption on an adsorp agents are used. More examples of one Further treatments are listed below.

In a likewise preferred embodiment, the Mesoporous silicas and metal silicates when used be used as an odor adsorbent in moldings. For example, if exhaust air is diverted to remove odors the method according to the invention by the described in Powdered silicas and metal silicates, see above there may be a significant loss of pressure. This after Part usually occurs when using moldings not or only weakly. Thereby extrudates, tablets ten or granules with a diameter of 0.05 mm and larger generally preferred. Really important is that due to the shape neither the mesopore volume nor the specific surface of the starting material we  be reduced considerably. In addition, the molded body have sufficient mechanical stability.

The molding process can consist of several individual steps Putting it together: First of all, this can be done by precipitation made porous and possibly amorphous silicate or Me tall silicate with uniform mesopore diameter with the Binder and other necessary additives mixed and optionally after adding water or others Liquids (e.g. methanol, ethanol) into one Plasticine can be processed further. The dry or slightly damp mixture, or plasticine can with corresponding aggregates in defined forms, such as Example cylinder, hollow cylinder, tubular or cylin such extrusions, with different shapes Shell surfaces are pressed. The greens obtained in this way per, whose diameter is preferably between 1 and 10 mm can then be at room temperature or elevated Temperatures, if appropriate in the presence of water vapor, be dried. Then the molded body in Presence of air, inert gas or oxygen at temperature calcined up to 1,100 ° C. The calcination serves to remove the template and the additives the green body and decisively influences the mechanical stability, the pore volume, the adsorption behavior and / or the specific surface.

In principle, all are suitable as binders for such Purposes of previously used connections. To be favoured Oxides, especially oxides of silicon, aluminum, boron, Use phosphorus, titanium, zirconium and / or magnesium det. Particularly preferred binders are silicon dioxide, aluminum minium oxides, titanium oxides and clay minerals. examples for Silicon dioxide precursors are precipitated or pyrogenic grains acids, silica sols, tetraalkoxysilanes, partially condensed Silicic acid ester or polysiloxane, for aluminum oxide (Pseudo) boehmite, for titanium dioxide anatase or brookite and  for clay minerals montmorillonite, kaolin, bentonite and Sepiolite.

The content of binder in the moldings, based on the porous silicas or Me calcined at 1,000 ° C tall silicates, can be varied in any range. However, it is preferably between 5 and 70% by weight.

As additives in the manufacture of for which he method according to the invention use moldings u. a. all for it suitable organi known in the art substances are used. These are preferably organic polymers such as cellulose, starch, Polyacrylates, polymethacrylates, polyvinyl alcohol, polyvi nylpyrrolidone, polyisobutene, polytetrahydrofuran, polygly kolether as well as fatty acid preparations and wax emulsions. These substances primarily promote the formation of a plastic mass during kneading, deformation and Drying step by bridging the primary particles and also cause the mechanical stability of the Shaped body during shaping and drying. These substances are removed from the shaped body again during calcining.

Bases or acids can be added as further additives become. Ammonia, amines or are suitable, for example quaternary ammonium salts and carboxylic acids such as play formic, acetic or propionic acid. It can too Mixtures of two or more of the above additives be used.

Polyalcohols, such as, for example, can be used as pore formers Fructose, pentagerythritol, cellulose or sawdust be set. These burn out during the calcination and leave additional mesopores and macropores in the molding by.

The moldings can then in various ways and Modified way. Of course, the po  red silicas and metal silicates with regular measurements sopores can also be modified before shaping. Examples of the modification are:

The incorporation of cations such as H ⁺ , Cs ⁺ , rare earth or noble metal cations by ion exchange.

The hydrophobization or functionalization by reaction with organosilicon compounds, such as X _4-n SiR _n with X = Cl, Br, I, OH, O-alkyl or O-aryl, R = alkyl or aryl radical or organofunctional groups, such as for example (CH ₂ ) ₃ SO ₃ H; (CH ₂ ) ₃ NH ₂ ; (CH ₂ ) ₃ N ⁺ Me ₃ Cl-; (CH ₂ ) ₂ PPh ₂ .

Incorporation of metal oxides by reaction with suitable precursor molecules, such as TiCl ₄ , TiBr ₄ , Ti (OEt) ₄ , TiCp ₂ Cl ₂ (Cp = cyclopentadienyl), Mn ₂ (CO) ₁₀ , Fe (CO) ₅ .

Installation of precious metals or metal oxides through impregnation tion with solutions of the metal or precious metal salts.

grind

The way in which the odor-producing substances with the porous silicas or metal silicates in Kon be brought in tact is essentially not decisive tapping. A temperature range from approx. -25 ° C to 50 ° C and however, a pressure of about 1 atm or above is imminent Trains t. The porous materials can be pure or together with Excipients, spreading agents, on carriers or in corre sp mixtures with other ingredients with the appropriate odor-producing substances are brought into contact.

It is also possible to use the described mesoporous pebbles acids and metal silicates in combination with other ge odor-controlling compounds or preparations use. Other adsorbents can, for example Activated carbon, carbonates, silica gels, aluminum oxides, silica acids, diatomaceous earth, clays, hydrophobic and hydrophilic zeo  be lithe. Definitions of hydrophobic and hydrophilic Zeolites are found, for example, in the document US 4,795,482. Other odor control compounds or Preparations can, for example, fragrant fragrance fe, chelators, oxidizing agents, bactericides or bacteria be riostatics.

The invention further includes hygiene articles in which mesoporous silicas or metal silicates are contained, characterized in that the silicas or Metalsi likate a uniform mesopore diameter or have a narrow mesopore radius distribution.

The method according to the invention is for the hygiene articles Adsorption of odor-producing substances. The In principle, hygiene articles can be used both in human (Body care, cleaning agents, etc.), as well as in tieri area (body care, use in stables, etc.) be turned.

The mesoporous silicas and metal silicates can ge adsorb odoriferous substances by humans or animals are excreted, or which, due to the excretions are formed later. Ausschei blood, menstrual fluids urine, faeces and sweat, but also other water mixtures.

One embodiment of the hygiene article can be a disposable adsorbent article for collecting from a source of given liquids and unpleasant smells generated by the collected liquids, wherein said article comprises at least in addition to the mesoporous silicas or metal silicates:
an adsorbent core agent for absorbing liquids;
a liquid impermeable backsheet covering said core agent on one side;
a liquid-permeable cover sheet, which covers the said core agent on the said back sheet opposite side.

This can include sanitary towels, diapers, incons ink pads or forearm shields. The construction of the This article is summarized below.

a) Adsorbing core agent

The adsorbent core agent can be any known core agent be used in hygiene articles. As adsorby The core substance is such materials compilations, the main task of which is liquid adsorb, store and distribute. In usually it is between the liquid impermeable Back sheet and the liquid-permeable cover sheet po sitioned. In an execution farm, the adsorbent Core agent from a first, the liquid distributing Layer, a second, the liquid storing Layer and optionally additional layers his. The first, the liquid-distributing layer is standing on the one hand in direct contact with the liquid permeable cover sheet c) of the hygiene article and on the other side with the one that stores the liquid Layer of the core adsorbent. It serves the To distribute liquid so that the adsorption capacity optimally utilizes the layer storing the liquid can be. The adsorbent core agent can be used as a tissue, Flakes, powder or in another form according to the state of technology.

The liquid storage layer can be made for all of the sen purpose known materials exist. Preferably who the materials used which are known in the literature as  "Hydrogel", "Superadsorber" or "Hydrocolloide" known are. Examples and detailed descriptions of the usable ones For example, materials can be found in the document EP 0 813 848.

Other layers in the core adsorbent can for example tools for the production of the core agents or the core agent can be reinforcing layers. You can depending on the application above, below or between the Liquid storage layer can be positioned. she should be such that the liquid is unobstructed can get into the storage layer.

One or more of these layers, especially the rivers liquid-storing layer can be such that they become in use or in contact with rivers expands three-dimensionally and thus the body hugs the user.

b) Liquid impermeable back sheet

The backsheet is used on the side of the adsorbie renden article that the liquid impermeable back leaf closes, no liquid can escape. It ver thus prevents clothing from becoming dirty due to the use of the adsorbent article. Accordingly spreader If used properly, the liquid is not necessary permeable backsheet that the white of the wearer's body test removed component of the adsorbent article.

In one embodiment, the backsheet can be a woven or be non-woven polymer film. In this case the preferred material of the back sheet polyethylene, it are other materials, such as Polypro pylene possible.

In another embodiment, the back sheet at be active. Breathable here means that the back kenblatt permeable to vapors, but not for liquids  is. The back is preferably breathable leaf not only for vapors, but also for air sig. A breathable back sheet allows evaporation of liquid in the adsorbent article. As breathable active backsheet can all known for this purpose Materials are used. Examples can be found a. in document EP 0 813 848.

c) Liquid-permeable cover sheet

As a liquid-permeable cover sheet, everyone can do so far cover sheets used for this purpose can be used. For example, it can be natural or synthetic Fibers or mixtures thereof, of verses with openings plastic foils, for example made of polyethylene or porous foams exist. It can be woven or not woven materials are made. Examples of applicable Cover pages can be found in the document, for example WO 94/22500.

The cover sheet covers the adsorbent article on the Side that lies against the wearer's body. The task of Cover sheet consists, among other things, of the wearer to give the given liquid to the adsorbent core agent th.

The cover sheet can consist of one or more layers consist, with cover sheets of two layers preferred are. The cover sheet should be whole and, if necessary the individual layers should also feel soft and be cuddly, and should be the skin of the wearer don't irritate.

At least two of the components (a) to (c), preferably al le three must be connected to each other to the adsorbie renden article. In the article everyone has passed partly one facing the carrier and one facing away from the carrier Page. The connections between the components are  preferably created so that each facing away from the carrier Side of the component closer to the carrier with (a) or (b) the side facing the wearer of the underlying Part (b) or (c) is connected. Do they exist individual components (a) to (c) themselves from several layers ten, these layers can preferably according to the same prin zip to be connected. The cover page can be directly or indirectly connected to the backsheet. Ver Binding the components can all known methods are used, for example fusing, sewing or Connect by ultrasound. Preferably, the Be parts glued.

As a crucial feature, the disposable ad contains sorbent articles mesoporous silicas or Metalsi likate for the adsorption of smells. He can already in the described forms, in particular as a powder or molding used in the adsorbent article. Becomes he used as a molded article, the molded articles are preferred less than 1 mm, more preferably less than 0.5 mm.

The adsorbent article can be in addition to the mesoporous Kie acids and metal silicates still other components Include odor control. These can be acidic, basic or neutral adsorbents, such as activated carbon, Silica gels, aluminum oxides, silicas, diatomaceous earth, clays, Starch, so-called "absorbent gelling materials", hydrophobic be and hydrophilic zeolites, cyclodextrin, chelators, such as Aminophosphates or EDTA, citric acid, boric acid, carbona te and bicarbonates. Other ingredients to smell Control can be, for example, bactericides or bacterio be static, which is a microbiological formation of scaffolding prevent chen. The adsorbent articles can also also contain odorants with a positive perception mask the unpleasant smells. The smell substances can be released continuously or only at con  cycle of the adsorbent article with aqueous liquid released.

Usually between 5 and 400 g / m ² , preferably between 100 and 300 g / m ^{2, of} the odor adsorbent, based on the total area of the adsorbent article, is used. The odor-absorbing components can be positioned in the article in any known manner. For example, it can be positioned above, below or within the adsorbent core agent (a) or be part of the liquid-permeable cover sheet.

Up to this point, the description only summarizes the fundamental properties properties of the adsorbent articles according to the invention together. More detailed descriptions and possible executions Forms of construction, material, shape, procurement unit and other properties of the adsorbent core by means of (a), the liquid impermeable back sheet (b) and the liquid-permeable cover sheet (c) can for example documents EP 0 806 194, EP 0 813 848, EP 0 513 933, EP 0 510 619, EP 0 347 746, EP 0 811 388, EP 0 811 389, EP 0 850 617, US H1579, US 5,873,963, WO 97/01317, WO 91/12030 or WO 95/24173 can be found.

The compilation of the individual components (a) to (c) as well as the mesoporous silicate or metal silicate to the Adsorbent article according to the invention can be in a loving embodiment according to the prior art done, as for example from the above document ment emerges.

It is also possible that the ad sorbent article has other aids. This can, for example, adhesive tapes or other fastenings be that help the adsorbent article when applying hold in a preferred position.  

Furthermore, the invention largely includes odorless Plastics in which porous silicas or metal silicas kate are included, which are characterized by that the silicas or metal silicates have a uniform chen mesopore diameter or a narrow mesopo have a radius distribution.

Plastics often have an unpleasant smell. However, to date little is known about the chemi known nature of these substances. Usually it will are low-molecular, volatile, organic compounds act against. The emitted connections can, for example be unreacted monomers. Furthermore, the Polymerization and / or further processing to some extent oxidation, decomposition and others unwanted by-products formed.

For numerous areas of application, it is necessary to smell to produce poor or free plastics. Examples of this are food and pharmaceutical packaging, drinking water pipes, furniture, carpets and carpets or components from Vehicle interiors.

A number of methods are known for the leakage of to reduce undesirable odors from plastics gladly. Most of it is the application of adsorbents such as activated carbon, silica gels, aluminum Umoxides, diatomaceous earth, clays and zeolites. For example in the patent EP 0522129 a process for reducing Odorants in the manufacture of drinking water pipes described from polyethylene or polypropylene. There will be hydrophobic zeolites used as in the document US 4,795,482. In this particular case the Odor control in plastics have the same disadvantages on how they are already described above.

The plastics claimed here are the fiction method for adsorbing odor-producing substances  based on zen. Mesoporous silicates and metal silicates can the plastic contained in or from the plastic released odorants effectively and permanently adsor beers.

All common plastics can be used as base materials are used, for example polyvinyl chloride, polyethylene duck rephthalate, polystyrene, acrylonitrile butadiene styrene (ABS), Polyester, polyamides, polyethylene, HDPE, polypropylene, ins special oriented polypropylene (OPP). In an execution Formation can also mixtures of different Polymerma materials are used.

To the properties of the plastic, for example the Elasticity or breaking strength, not negative influence, should the average particle size of the Ge mesoporous silicas and Silicates smaller than 60 µm, advantageously between 1 and be 20 µm.

The plastics according to the invention can contain as much silica and metal silicates with a narrow mesopore distribution contain that a sufficiently good reduction in Ge ruchs is achieved. The exact proportion is of many fact ren dependent, for example on the desired degree of Ge odor reduction, from polymer material or bedin under which plastics will later be used the. A range from 0.01 to 20% by weight is preferred porous silicas or silicates by mass of the plastic used.

The silicas and metal silicates with narrow Mesoporenra dien distribution can be in the known ways in the form of a so-called masterbatches or as a dry blend ver) be added to the plastics. In the first case first becomes a masterbatch in a manner known per se from the underlying plastic and up to 50% by weight of silica or metal silicate. in the  following step is a mixture of the masterbatch and the underlying or another plastic in the for the ratio corresponding to the final concentration of the zeolite nis in standard equipment, for example an extruder, manufactured and processed immediately if necessary. When the odor adsorbent is added as a dry blend, the Mixing and further processing in appropriate apparatus ren. In both cases it is imperative that the Mesoporous silicas or metal silicates evenly in the Polymer are distributed.

The invention further comprises masterbatches which are used for producing position of the claimed plastics are used. These masterbatches can contain a portion of mesoporous Kie silica and / or silicates of up to 50 wt .-%, based on the finished master batch. The master batches are made from the underlying plastic and the mesopo red silicas and / or metal silicates as a dry blend prepared, the silicas and / or metal silicates are added to the plastic in the molten state, and the mixture is mixed thoroughly.

It is advantageous if the mesoporous kie used acid and / or metal silicates first by heating be completely freed of water before entering the Plastic are introduced.

In one embodiment of the invention, a single mesoporous silica, a single metal silicate or Ge mix from it or mix with others according to the state of the art Technically suitable odor adsorbents to the plastic are given.

In one embodiment, the plastics can be packaged as a pack kungsmaterial or packaging of all kinds for food and drugs are used. This includes, for example white cups, boxes, bags, pouches, bowls, bags, Packaging coatings or foils. The slides can  again used to make bags, bags, etc. become.

The invention further includes the use of the described benen plastics in any shape, the inside clearing of motor vehicles, for example as components or decorative item. Furthermore, the Invention the application of plastic in the form of textile fibers as well as in products that are wholly or partly made from sen textile fibers exist. These can, for example Fabrics, clothing, carpets or carpets.

The method for removing odors through adsorption on porous silicas and metal silicas ten has the advantage that odorants from different classes are equally well and permanently bound become. This is why in many cases there are smells are generated by complex mixtures of substances, not nope tig to take mixtures of different adsorbents.

Another advantage is that the adsorption used mesoporous silicas or metal silicates are white powders and therefore an aesthetically pleasing gu te appearance.

Another advantage is that for inventors The method according to the invention used silicas and metalsi likate from simple raw materials and in simple, manufacturing processes that conserve energy and raw materials are.

After all, the silicas and metal used silicates not combustible, so that the method according to the invention can also be used in areas where not can be used with flammable adsorbents.

Examples

In the experiments, the concentrations are different Odor substances in the air that protrudes from the adsorbents certainly. This can be done by two methods the one for which there is a reagent

o-phthalaldehyde reagent (OPA reagent)

First, about 1.5 ml of o-phthalaldehyde solution (10 mg / ml in ethanol) in 90 ml of sodium borate buffer with a pH of 9.5 ge dissolves and then about 1.5 ml of 2-mercaptoethanol solution (5 µl / ml ethanol) in this solution.

inverse o-phthalaldehyde reagent (inverse OPA reagent)

Approximately 1.5 ml o-phthalaldehyde solution (10 mg / ml in ethanol) and 1.5 ml propylamine solution (10 mg / ml in ethanol) dissolved in 90 ml of pH 9.5 sodium borate buffer.

example 1

In the experiment, different adsorbents on ih suitability tested, neutral odorants effective to ad sorb. As a model connection of a neutral smell propane thiol.

Procedure: In a 1 liter Erlenmeyer flask (gas volume 1100 ml with septum screw cap) become 0.5 g of the investigated adsorbent weighed. Then 2 µl Propane thiol injected onto the glass wall of the flask that the sample of the adsorbent is not wetted. After a few The propanethiol liquid drop is full in seconds continuously evaporates (this corresponds to 1.5 mg propanethiol per Liters of air). With a gas-tight syringe, after 1 and 4 h 100 ml of gas volume are removed from the flask and passed through a septum in a closed jar with fresh herge given inverse OPA reagent. By adding the Propanthiols can be found in the inverse OPA reagent Amine and the o-phthalaldehyde the corresponding isoindole Form derivative. The thiol acts as a reducing agent  and only enables the formation of the isoindole derivative. In order to all added propanethiol to form the isoindolderi vats leads, the sample is heated to 110 ° C. Subsequently we in the solution by means of HPLC the content of the isoindole derivative determined quantitatively. That way by a calibration curve from the amount of isoindole derivative Residual amount of propanethiol in the gas phase above the adsorbent determine. The results of the investigations are presented as re relative propanethiol amount given in the gas phase.

With this method different adsorbents are examined:
Comparison sample; not according to the invention: a synthetic zeolite of structure type A (activation by calcination at approx. 540 ° C.)
Comparison sample; not according to the invention: Wessalith® CS; Wessalith® CS is a product of Degussa-Hüls AG, Germany and contains a zeolite of structure type A as an odor adsorbent.
Comparison sample; not according to the invention: a synthetic zeolite of structure type X
According to the invention: The product STX 1000® from Degussa-Hüls AG, Germany. This is an amorphous, porous silicate with an average pore diameter of 3 nm and a narrow mesopore radius distribution, which has no pronounced long-range order. The mesopore volume is 0.9-1.1 ml / g, the total pore volume is greater than 4.5 ml / g and the specific surface is 900-1100 m ² / g. Further properties of the product can be found in the "Preliminary Product Information STX 1000", PI 2037; Degus sa-Hüls AG, Germany.

The comparison substances 1) to 3) are according to the status of technology alone or in mixtures on a large scale as Odor adsorbents used.  

The results of the tests are summarized in Table 1 summarizes.  

Table 1

Adsorption of propanethiol

Claims (18)

1. A method for removing undesirable odors from gaseous and liquid-containing environment by adsorbing the odor-generating substances on porous silicas or metal silicates, which is characterized in that the silicas or metal silicates contain a uniform mesopore diameter or a narrow mesopore radius distribution. 2. The method according to claim 1, characterized in that the half width of the mesopore radius distribution of the mesoporous silicas and metal silicates smaller than 5 nm, preferably less than 3 nm. 3. The method according to claim 1, characterized in that the mesoporous silicas and metal silicates none Show long-range order. 4. The method according to claim 1 to 3, characterized in net that the mesopore volumes of the mesoporous pebbles acids and metal silicates greater than 0.5 ml / g, preferred are greater than 0.8 ml / g. 5. The method according to claim 1 and 4, characterized net that the mesopores in the mesoporous silicas and metal silicates have an average pore diameter from 2 to 10 nm, preferably from 2 to 5 nm. 6. The method according to claim 1 and 5, characterized in that the mesoporous silicas and metal silicas te have a specific surface area greater than 500 m ² / g, preferably greater than 700 m ² / g. 7. The method according to claim 1 to 6, characterized in net that the silicas and metal silicates by precipitation were produced.   8. The method according to claim 1 to 7, characterized in that the silanol group density of the meso porous silicas and metal silicates used is less than 3 OH groups per nm ² , preferably less than 2 OH groups per nm ² . 9. The method according to claim 1 to 8, characterized in net that the mesoporous silicas and Metal silicates have little or no micropores sen. 10. The method according to claim 1 to 9, characterized in net that the total pore volume of the mesoporous pebbles acids and metal silicates is greater than 3.0 ml / g. 11. The method according to claim 1 to 10, characterized in net that the mesoporous silicas and metal silicas te in the form of a powder. 12. The method according to claim 1 to 10, characterized in net that the mesoporous silicas and metal silicas te be used in moldings. 13. Hygiene articles in which mesoporous silica or Metal silicates are contained, characterized in that the silicas or metal silicates have a unit mesopore diameter or a narrow one Have mesopore radius distribution. 14. Disposable, adsorbent articles for collecting liquids emitted from a source and unpleasant smells generated by the liquids collected, at least containing an adsorbent core agent for absorbing liquids, a liquid-impermeable backing sheet, a liquid-permeable cover sheet and an adsorbent for odor-producing substances, characterized in that

• a) the adsorbent for odor-generating substances is a me soporous silicate or metal silicate, and
• b) the mesoporous silicate or metal silicate has a narrow mesopore radius distribution.

15. Odor-reduced and odorless plastics, min Contain at least one silica or a metal silicate tend, characterized in that the silicas or Metal silicates have a narrow mesopore radius distribution point. 16. Plastics according to claim 15, characterized in that the mesoporous silicas and metal silicates have no long-range order. 17. Plastics according to claim 16, characterized in that the mesopore volumes of the mesoporous silicas and metal silicates are greater than 0.5 ml / g, preferably greater than 0.8 ml / g, the mesopores in the mesoporous silicas and metal silicates have an average pore diameter from 2 to 10 nm, preferably from 2 to 5 nm, and that the mesoporous silicas and metal silicates have a specific surface area greater than 500 m ² / g, preferably greater than 700 m ² / g. 18. Plastics according to claim 3, characterized in that the polymer material is polyvinyl chloride, polyethylene terephthalate, polystyrene, acrylonitrile butadiene styrene (ABS), polyester, polyamide, HDPE, polypropylene, esp special oriented polypropylene (OPP), polyethylene or a mixture of one of these materials with at least least any other polymer material.