DE1962282A1 - Non-woven disposable towel and process for its manufacture - Google Patents

Description

Carl Freudenberg M-. December 196 9

6 940 Weinheim / Bergs tr.Dr.Z / Sn - ON 54-2

Non-woven disposable towel and process for its manufacture

Nonwovens bound with binding agents have been used for years for cleaning dishes, glass, etc. at A uniform non-woven fabric has been uniformly impregnated with a binder in these cloths.

The production of the known non-woven cloths has hitherto been carried out by the so-called dry route. So it was made with the help of a card and a crosslayer formed a fiber fleece, which was then impregnated. The methods for doing this are in the monograph "Nonwoven Fabrics" by Nonwovens Associates, P.O. Box 328, Cambridge 39, Massachusetts, 1959 described in detail.

The invention now relates to the production of such nonwoven fabrics in a cheap way. This makes it possible to use the Throw away wipes after a short period of use.

The new disposable wipes are produced according to the invention exclusively on the so-called wet route, here you work in a similar way to paper production. The one used to manufacture The staple fibers required for the nonwoven and about 1 to 30 mm long are suspended in a large excess of water and then poured on a steep sieve machine.

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A nonwoven web then remains on the screen. However, in order to give it the required strength, a binder is added to the pulp (slurry liquor) at the same time. This binder is preferably brought to coagulate before it is poured off. The small coagulated particles preferably settle on the surface of the fibers whirled up in the liquor. If such fibers are now poured onto a sieve, the fibers already have a binding agent on their surface. It will be the wet mat to dry at temperatures between 110 and 150 ⁰ C. At the same time, hardening or vulcanization of the binding agent takes place, which gives the fleece the required strength. The loose fiber fleece has become a stable fleece.

When carrying out the already known wet route for the production of nonwovens, a uniform structure is obtained Fleece in which the binding agent is evenly distributed.

The disposable towel according to the invention, however, now consists of three Layers. The middle layer is practically binder-free, which makes it very absorbent. This absorbent The middle layer is for its part covered at the top and bottom with further fleece layers, which, however, have a high binder content exhibit.

The two outer layers, as a result of the high binder content are very stable but are nonetheless porous, serving as a protective layer for the highly absorbent middle layer, so to speak.

The three layers are fed to a hydroformer in the so-called three-component approach system. This is done as can be seen from FIG. One recognizes there the steep sieve ¹ K continuously revolving around auxiliary rollers. Water is fed to this steep sieve via lines 1, 2 and 3. Fibers and binders are first stored in a storage container (not shown)

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bloated. The binding agent is deposited on the surface of the floating fibers by coagulation. These Aqueous fiber suspension is then fed via the lines 1 and the steep sieve 4. On a second, also not A further fiber pulp reaches the steep sieve via the line 2. Be in the second storage container cellulose fibers only (possibly with very little addition other fibers) slurried. At the same time, in this liquor is a plastic powder such as polyvinyl acetate.

In this way, three layers are deposited on top of each other on the steep sieve 4 ( Deposit. A previous mixing of the individual fiber types is prevented by the guide plates 5 and 6, which are above of the steep sieve and come quite close to its surface. At the upper end of the steep sieve can a three-layer structure can now be removed, the structure of which can be seen in FIG. II. Layers 8 and 9 are made of fibers that have binders on their surface, e.g. coagulated latex. The middle class 7, however, only exists made of fibers without the addition of binders. For this purpose, the middle layer 7 contains a plastic powder.

In the nonwoven fabric formed, the three layers are still extremely loosely attached to one another. In addition, the fiber I planar structure does not yet show any stability.

It is therefore first dried at temperatures from 110 to 160 ⁰ C. The binder vulcanizes or hardens in the layers 8 and 9, giving them a high level of inherent stability. Then the pre-dried three-layer structure is embossed in dots or under a waffle-like pattern. The plastic particles in the middle layer soften and thus establish a firm connection to the two outer layers 8 and 9 at the points at which the action of heat and pressure took place, so that the entire structure is now extremely stable and constantly rejuvenated .

BATH

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The three-layer structure is preferably used - as from the III can be seen - weld along certain lines 12 and 13. So many small squares with a high one are formed Absorbency. The consolidation of the individual layers with one another therefore only takes place along narrow weld lines 12 and 13.

As already mentioned above, the middle layer should consist entirely or at least predominantly of highly absorbent cellulose fibers. That any additional adhesive powder contained therein remains inside | half of those formed by the weld lines 12 and 13 Squares inert in the end product. It was just along the weld lines Made sticky by the action of heat and pressure, which makes the use of the three layers longitudinally Certain lines is produced, an impairment of the absorbency of the middle layer by the added thermoplastic Particles do not occur even if they make up about 40% of the weight of the pulp fibers of the middle layer. In general, however, it is sufficient to add 10 to 20% by weight of thermoplastic powder based on the weight of the fibers the middle class.

So while for the middle class high-absorbency cell) material is required, fully and semi-synthetic as well as natural fiber material is preferred for the top and bottom layer. One can but also add up to 50% of a highly absorbent cellulose to the outer layers.

In this way, porous outer layers are obtained which have a high level of abrasion. Such nonwovens are even suitable for scrubbing without the fear of fibers fluffing out on the surface.

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example

One first prepares a fleet consisting of

0.5 kg Flox N / 3 decitex, 10 mm cutting length and 0.5 kg of bleached birch pulp.

Subsequently, in a second fleet

1.0 kg of spruce pulp and 0.2 kg of polyvinyl acetate powder

3 suspended in 0.5 m of water.

The first liquor is now fed to the allocation 1 and 3 in FIG. I and the second liquor via the feed line 2 to the hydroformer and deposited into a flat structure. The metering of the feed is chosen so that the transverse and the upper fleece has a weight of 20g / m, the cellulose pulp

2 gives a weight of 50 g / m. This is followed by drying.

2 The final product has a weight of 90 g / iB

The reference number 10 in Fig. I denotes the usual baffle in steep sieves, which the movement of the liquid, which is under Pressure flows into the suction device, dampens.

Below the steep sieve 4 are the various suction chambers 11 is shown schematically.

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Claims (1)

Claim Nonwoven fabric, consisting of a thermoplastic powder containing middle layer 7 of highly absorbent fibers, in particular containing cellulose fibers as well as two fully vulcanized binders enclosing this middle layer Fiber layers 8 and 9, which in turn consist of more than 50% synthetic or semi-synthetic fibers, with ^ the three layers along certain lines or on certain ones Points to each other through softened thermoplastic powder are connected. Blank page