The invention relates to a household paper or paper for hygiene according to the preamble of Claim 1 and to a process for increasing the softness and reducing the volume of such papers when packed.

It is known to produce household or hygiene papers from at least one, preferably twc to four 1; -^rs of tir<nie paper, the product being provided with n emboss .t. In '. _?. case of single- and multi-layered papers, this ossment necessitates surface texturing which makes the paper pleasantly soft. In the case of a multi-layered household or hygiene paper, the embossment also serves to stick the individual layers of tissue paper together. An example of such a household or hygiene paper and its production is given in DE 39 42 536 C2.

The properties for use of household or hygiene papers have to meet various requirements. For example, hygiene papers such as toilet paper, handkerchiefs or cosmetic cloths on the one hand have to be as soft as possible but on the other hand have to have a certain degree of strength. For economic and ecological reasons, which are becoming increasingly important nowadays, consumer goods in general and consequently also household or hygiene papers generally have to be packable as compactly as possible to save packaging material as well as transportation, storage and shelf space in the places of sale. The saving in packaging material also allows disposal costs imposed on manufacturers of such papers owing to the laws governing waste management (keyword: "green point") to be reduced.

On the basis of the problems posed, the object of the invention is to provide a household or hygiene paper in such a way that it has a smaller packed volume with increased softness and virtually unchanged strength. In terms of the process, the softness of

household or hygiene paper is to be increased and its packed volume to be reduced by the invention.

This object is achieved by the features mentioned in the characterising part of claim 1 or claim 3. It has been found that owing to the indicated after-calendering of the paper after the embossment thereof and optionally sticking of layers with practically insignificant losses of strength, on the one hand a clear increase in softness and, on the other hand, a clear reduction in the thickness of the paper can be achieved. The jump in softness is manifested in that a toilet paper of average softness produced in the conventional way acquires softness corresponding to that of a cosmetic cloth merely due to the after-calendering. With regard to the reduction in volume, the roll volume, for example, of toilet paper can be reduced by up to 50% with the same number of sheets and therefore same length of paper, owing to moderate calendering. This means that up to twice as much toilet paper can be placed in a large packing with the same roll and therefore packing volume.

Claims 2 and 4 give advantageous ranges of values for the linear pressure of the calendering rollers. Such linear pressure values can already be achieved owing to the inherent weight of conventional calendering rollers. To achieve the higher linear pressure values within the specified range, it is sufficient to load the calendering rollers with pressure cylinders having a moderate cylinder pressure below 1 bar.

Further features, details and advantages of the invention can be inferred from the following description in which an embodiment is described in detail with reference to the accompanying drawing.

The drawing shows schematically the construction of a toilet paper according to the invention and the after-calendering thereof.

As shown in the drawing, a toilet paper 1 according to the invention consists of three layers 2, 3, 4 of tissue paper having a weight per unit area of about 15 g/m ² . The upper layer 2 on the one hand and the two lower layers 3, 4 on the other hand are each provided with mound-like embossments 5, 5' which each extend concavely inwardly from the upper side 6 and lower side 7 of the paper. Adhesion between the layers 3, 4 on the one hand and the layer 2 on the other hand is achieved at the peaks 8 of the embossment 5' of the underside of the paper 7 owing to the embossing pressure.

The mutual offset of the mound-like embossments 5, 5' in the layers 2 or 3 and 4 do not produce roughening mounds from the upper side 6 or underside 7 of the paper, so such a toilet paper 1 is already relatively soft. As also shown in the enlarged detail in the accompanying drawing, a traditionally produced toilet paper 1 of this type has a relatively great thickness owing to the bulking by the embossments 5, 5'.

It is accordingly proposed according to the invention that a toilet paper 1 produced traditionally up to this production stage be passed through, a pair of calendering rollers 9 with an upper pressing roller 10 and a lower opposing roller 11 in order to subject it to after-calendering. The pair of calendering rollers 9 is completely conventional in construction and. therefore requires no further explanation. It should merely be mentioned that the pressing roller 10 operates under the load of its inherent weight or is loaded against the opposing roller 11 by the two pressure cylinders 12, 13 with relatively low cylinder pressures p of less than 1 bar. The linear pressure values attainable are therefore in the range of 10 to 30 N/cm approx.

The strength of the toilet paper 1 is virtually unaffected by this after-calendering, but its softness is increased and its thickness so considerably reduced that considerably more sheets of toilet paper 15 pass onto a roll of toilet paper 14 of unchanged standard diameter D.

The following table quantitatively demonstrates these qualitative statements. The measurements were taken on conventional commercial toilet paper produced by the applicants. The toilet paper products "BESS Perfect" (2-layered) , "BESS Exclusiv" (3- layered) and "BESS First Class" (4-layered) were used. These toilet papers were investigated without calendering and subsequent to after-calendering with a linear pressure of about 20 N/cm. The breaking strength was measured dry in the longitudinal and transverse direction of the machine and the relationship between number of sheets and diameter when the toilet paper was wound onto conventional rollers was measured with comparable winding tensions. The softness was evaluated by a conventional panel test.

The measurements led to the results compiled in the following table.

Table: Comparison between uncalendered and after-calendered toilet papers

Parameters 2-layered 3-layered 4-layered uncal. after- al. uncal. after-cal. uncal. after-cal

Breaking strength

(dry)

Longitudinal (N/50 mm) 16.7 17.0 18.6 17.6 21.6 21.1

Transverse (N/50 mm) 5.3 5.0 6.4 5.7 7.7 7.1

Softness 3.0 3.9 3.0 4.2 2.8 4.1

No. of sheets 250 347 200 380 152 261 Roll diameter (mm) 105 109 130 120 125 121