DE2142239A1 - PROCESS FOR MANUFACTURING POROESE, HIGHLY ABSORBENT AREAS - Google Patents

Description

D *. RER. NAT. DIPL. CHEM.

HANS UHLMANN

PATENT ADVOCATE ι ■ ". ·". '* * J

VIERSEN / RHLD. - ■ ^; · ■■ · jj; _';'

GLADBACHERsiwrM ^ tder: Feldmühle Anlagen- · 'and

Fernrufisöif Produktlonsgesellsohaft mbH.

4 Düsseldorf-Oberkassel, Fritz-Vomfelde-Platz 4 Attachment to the entry from August 23, I97I ^ \

Process for producing porous, highly absorbent surfaces

The invention relates to a method for producing flat structures with high air and water vapor permeability and high water absorption capacity and represents a further development of the subject of the German patent application P 20 44 339 · ^. The subject of the parent application is a method in which two nonwoven webs with one in between located, cavities having plastic layer are combined, according to the invention at least on the inner sides the nonwoven webs a coagulant for the plastic is applied in a non-full-area form and then the Plastic in the form of a foamed dispersion is introduced between the nonwoven webs and dried.

It has been found _r to improve the properties of this sheet further _daö_es-by is desirable some applications, especially in such a way that the outer surfaces are wear-resistant, that is not prone to pilling, and the sheet compared to smooth surfaces grip as in window panes. However, it is essential that the high porosity and the associated high air and water vapor permeability are not impaired.

According to the invention, this object is achieved in a method for producing flat structures with high air and water vapor permeability and high water absorption capacity by combining two webs of fleece with one in between

309810/0883

BATH ORIGINAL

Plastic layer having cavities, v / above at least a coagulating agent for the plastic in a non-full-surface form on the inside of the nonwoven webs, and then the plastic is applied in the form of a ve rs eh. te η dispersion introduced between the nonwoven webs m; .-: \ iioti ^ oknet is solved by also foaming plastic in the form of a ve r on the outside of the nonwoven webs. Dispersion is applied, then a coagulant is applied and the outer coating is dried.

By applying a foamed plastic dispersion on the outsides of the nonwoven webs, too, the fibers of the outsides of the nonwoven web are firmly bound will / and cannot come off even after prolonged use. The subsequent discontinuous application of a Coagulant has a double technical effect. On the one hand, continuous film formation is avoided, on the other hand is used in the final treatment step for the whole Planar structure, namely the dissolving of the coagulant at the points where the coagulant acted, porosity achieved and so the good air and water vapor permeability of the entire surface structure. The prevention of continuous film formation is also essential, because this achieves a certain profiling of the surface is necessary for the desired grip of the surface ^ · »image, especially compared to glass and other smooth materials is crucial.

The foamed plastic dispersion can be applied to the outer sides of the nonwoven webs on the already finished sheet-like structure, ie after the foamed dispersion has been placed between the nonwoven webs and subsequent drying. However, a method is preferred in which the outer coating is carried out before the two VlLesbnLueri are combined and before the Ki-tnsfcstoffawischenauhi'ilii; nuf aie

3098 10/0883

BATH ORIGINAL

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Outer seeding of the nonwoven webs present in isolation takes place. This procedure has advantages, especially with regard to the drying technique, since no liquid comes out of the outer coating can be driven into the intermediate layer.

As foamable plastic dispersions for the exterior practically the same plastics come into consideration * as for the intermediate layer, so we will not go into it further here is. The same applies to the coagulants, where sodium sulfate is best in this case as well has proven itself.

The amount of the coagulant depends to some extent on the plastic dispersion and the thickness of the application. With the usual order-weighted i-n-the order of magnitude from 15 to 30 g ^ e outer layer, 10 - 50 g sodium sulfate per square meter are sufficient, with relatively wide expansion within this Limit the permeability reached with increasing Application amounts of sodium sulfate also increases. For quantities over 50 g, however, the permeability that can still be achieved is only low, so that there is a use of sodium sulfate over this Amount is not worthwhile and other properties of the fabric are adversely affected.

The coating according to the invention is described below using an example the outer sides of the fabric described in more detail;

On a pre-hardened fiber fleece with a weight of 49.6 g / m ^ a plastic foam is made on the base with a squeegee from z.3. Acrylic resins, the usual foaming and thickening agents contains, continuously applied and unmlifcelbar then finely powdered sodium sulfate is applied in a non-homogeneous form with the help of a vibrating sieve.

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309810/0883

BATH ORIGINAL

2U2239

The thus coated fibrous web is then dried and then briefly fixed in the binder at 130 ⁰ C at 120 G ^0.

The air permeability of a fiber fleece treated in this way. according to Schopper results from the following table:

Amount of Na ₂ SO ₂ , air permeability

O g / m ² 12th g / m ²
ε / m ² 24
36 g / m ² 48

21.1 l / min.

^ 8.8 l / min.

46.4 l / min.

49.6 l / min.

54.4 l / min.

The air and vapor permeable ones provided with outer layers in this way Fiber fleeces are then, as in the parent application described, to the final sheet-like structure with an intervening plastic layer having cavities further process in the manner described there

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Claims (2)

Claims Θ Process for the production of planar structures with high air and water vapor permeability and high water absorption capacity by combining two nonwoven webs with a plastic layer with cavities in between, wherein a coagulating agent for the plastic is applied in a non-full-area form at least to the inner sides of the nonwoven webs, and then the plastic In Porm a foamed dispersion is introduced between the nonwoven webs and dried according to the patent application Ref .: P 20 44 339 · 4, characterized in that also on the outsides of the nonwoven webs of plastic are applied in the form of a missed dispersion, followed by coagulants applied discontinuously and the outer coating is dried. 2. The method according to claim 1, characterized in that the outer coating prior to the joining of the two nonwoven webs and the introduction of the plastic intermediate layer Application on the outside of the insulated non-woven web o.i follows. 309810/0883 ' ORIGINAL