DE19708693A1 - Filter material for water filters or as a combined filter material for vehicle interiors - Google Patents

Abstract

The filter material, with high air permeability, has an asymmetrical highly permeable nonwoven material with a dense and an open side containing granular or spherical adsorbent materials. It is heat laminated to a highly permeable covering. The asymmetrical nonwoven material is formed by tearing a bulky material through the centre, so that each half has a dense and a loose side. One is used as a carried for the adsorbents, and the other is a cover. The nonwoven material charged with adsorbents is covered by a polyester or polyamide nonwoven material of high air permeability, with a light thermal lamination bond. The nonwoven material to carry the adsorbents is wholly or partially of a material with fibres which become tacky when heated, and at least partially of polyolefin fibres. The adsorbents are active carbon, mol. sieves, porous polymers or ion exchangers. A combined filter structure is bonded by heat or an adhesive at intervals. The air permeability is at least 800 l/m<2>/sec. and pref. 1000 l/m<2>/sec., at a water column of 10 mm. The nonwoven material can have a layer of melt blown fine polypropylene (PP) fibres. The nonwoven material can be laminated to an uncompressed polycarbonate nonwoven material.

Description

The main application describes a flat filter material consisting of egg Nem nonwoven fabric with spacing between the load the fibers so that the tightness increases in this direction with granular adsorbents whose particle size depends on the direction of flow takes. The invention accordingly requires an asymmetrical fleece, which can be produced for example by roughening.

Surprisingly, an economical way has now been found to produce asymmetrical nonwovens. Nonwovens are often smoothed on their surface, which can be carried out in a flat laminating machine driven on a gap, among other things. By mechanically separating the nonwoven web into an upper and a lower part, which, for. B. can be done very easily by tearing them apart ( Fig. 1), he will hold 2 asymmetrically constructed halves, with a dense structure where the outside was once, and a very loosened structure where the separation took place. The loosened side can be sprinkled with granular adsorbents that can penetrate deeply into the now very open fleece, but do not trickle through the denser underside (the original outside). Although granular adsorbents with a broad particle size distribution are preferred, such is not a must.

The penetration of the adsorbents can be supported by shaking or tapping will. In any case, the excess on top must be removed become, for which the expert has different options, such. B. From suck the nonwoven web. Namely, for later, preferably thermal, consolidation or lamination sufficient free fibers on the sprinkled page are available.  

There are many options for the production of flat filters as described. Basically, nonwovens are made of at least partially thermoplastic fibers suitable, nonwovens made of polyolefin fibers are preferred because they are Heat quickly become very sticky and the adsorbents fi very permanent xieren. Only if a desorption at relatively high temperatures is desired, one is on polyester or polyamide fleece or fiber mixture or bicomponent fibers.

A suitable way to produce the filters according to the invention is to cover one half of the split nonwoven with adsorbents and to use the other, unloaded half, as a cover. Another option is to use a light, highly air-permeable fleece as a cover. If you are working with a polyolefin fleece as a carrier for the adsorbent and there is no laminating machine with teflon-coated parts available, you can cover both sides of the carrier fleece with a light polyester fleece to prevent sticking in the laminating machine. Such fleeces are known under the name "Reemay". Depending on the intended use, the thickness of the fleece can be up to several cm, but is considerably reduced when laminating. As a guideline it can be said that the thickness (mm) should preferably be (g / m ² ) × (0.05 to 0.15) before the basis weight. An amount of adsorbent that is 0.5 to 3 times the fleece weight can normally be accommodated.

The most commonly used adsorbent is activated carbon, which is used both as also referred to as splinter coal - as well as shaped coal or as spherical coal can be used. Coals or spherical coals are preferred Particle sizes from 0.05 to 3 mm, in particular 0.1 to 1 mm.

Other suitable adsorbents are molecular sieves and porous polymers, as they e.g. B. are offered under the name "Sorbathene".  

Very interesting adsorbents are also ion exchangers to remove gases that are difficult to adsorb on activated carbon from air currents. Strongly acidic cation exchangers are suitable for adsorbing NH ₃ , which is of particular interest in clean room technology.

On the occasion of the production of the invention, with ion exchangers loaded filters, it was found that such mats or plates, which in Thicknesses of several centimeters can be made themselves are suitable for water purification because the flow resistance is very low and a plate-shaped filter (water softener) is very easy to insert in many cases build is.

example 1

A PE fleece from Scandfilter with a basis weight of approx. 100 g / m ² and a thickness of approx. 13 mm was separated into two asymmetrical halves, each with an open and denser side, by pulling them apart. One half was evenly sprinkled with the open side upwards with a piece of coal from Pica, particle size 0.3-0.8 mm, in an amount of 210 g / m ² , until the PE fibers were again approx. 40-50% became visible. The second half was laminated with the open side to the coal on a Kannegießer laminating machine with a non-stick layer at 180 ° C onto the loaded half. The result was an approx. 3 mm thick filter layer with 210 g / m ² activated carbon and an air permeability of 1500 l / m ² .sec. at 10 mm WS.

Example 2

The fleece of Example 1 was again divided into two halves, each with a thick and an open side, and the open side, as in Example 1, was loaded with activated carbon. Then both the dense and the open loaded side were covered with a 15 g / m ² heavy Reemay fleece and this sandwich was laminated together as in Example 1. The result was a filter with very similar properties.

Example 3

The fleece of Example 1 was split again in half with a dense and an open side. The open side was then loaded with approximately 150 g / m ^{2 of} cation exchange beads (Dowex HCRS H⁺ from DOW Chemical Cal) and shaken. The unloaded half was then laminated onto the loaded half, as in Example 1. The result was an approx. 3 mm thick material, which proved itself as an adsorption filter for NH ₃ and volatile amines, but also as a water softener for household appliances.

Example 4

As in Example 1, granular molecular sieves (part size 0.1 to approx. 1 mm) is used.

Example 5

Analogous to Example 1, spherical polymeric adsorbents were based Styrene / divinylbenzene, known under the name "Sorbathene", inserted puts.

Example 6

The material of Example 1 was coated with a La on the side of the cover fine PP fibers that were applied using the melt-blown process, Mistake. The result was a combination filter for particles and pollutants, which is suitable for Automotive interiors was suitable.  

Example 7

The half of Example 1 loaded with adsorbents was laminated together with an undensified polycarbonate fleece, which is used as a particle filter. The result was an approx. 5 mm thick combination filter with an activated carbon content of 210 g / m ² and an air permeability of approx. 1200 l / m ² .sec. at 10 mm WS. In order to avoid a change in the structure of the particle filter, the lamination temperature was reduced by 20 ° C and the contact pressure was reduced.

In all examples, the adsorbents (or ion exchangers) were permanent fixed and withstood washing easily.

Claims (8)

1. Filter material with high air permeability, made of an asymmetric high-permeability fleece with a dense and an open one Side, the open side of which with granular or spherical adsorbents is loaded and thermally with a highly air-permeable cover is laminated together. 2. Filter material according to claim 1, characterized in that the asym metric fleece by separating a puffy surface Fleece happens in such a way that two asymmetrical halves with one side each with a dense structure and one side with an open structure door arises. 3. Filter material according to one or more of the preceding claims che, characterized in that of the two asymmetrical Non-woven halves of claim 2, one as a carrier for the adsorbents and the other is used as a cover. 4. Filter material according to one or more of the preceding claims che, characterized in that the asymmetrical, with adsorbents loaded fleece on one or both sides by a light, thermally open laminated polyester or polyamide fleece with high air permeability is covered. 5. Filter material according to one or more of the preceding claims che, characterized in that the fleece carrying the adsorbents consists entirely or in part of fibers which increase in temperature hung sticky.   6. Filter material according to one or more of the preceding claims che, characterized in that the fleece is at least partially made of Po there is lyolefin fibers. 7. Filter material according to one or more of the preceding claims che, characterized in that the adsorbents activated carbon, molecule are sieves, porous polymers or ion exchangers. 8. Combined filter, in particular for motor vehicle interiors, characterized in that a suitable particle filter with the material according to one or more of the preceding claims is thermally or optionally un using a discontinuously applied adhesive verbun, the air permeability at least 10 mm WS 800 l / m ² .sec., Preferably 1000 l / m ² .sec.