EP1001879A1

EP1001879A1 - Method for making a relatively soft product, and the product itself

Info

Publication number: EP1001879A1
Application number: EP98941345A
Authority: EP
Inventors: John Dunn Mclain; Brian Hunt; George Rutherford
Original assignee: SCA Hygiene Products GmbH
Current assignee: Essity Germany GmbH
Priority date: 1997-08-08
Filing date: 1998-07-16
Publication date: 2000-05-24
Anticipated expiration: 2018-07-16
Also published as: HUP0003200A2; US6440564B1; SK1652000A3; AU746109B2; AU8976098A; KR20010022732A; HRP20000064A2; EP1001879B1; HUP0003200A3; DE19734414A1; CA2297728A1; CO5050381A1; ES2197501T3; BR9811879A; CN1095741C; PL338560A1; CN1272079A; DE59807981D1; JP2001513461A; AR013402A1

Abstract

The invention relates to a relativety soft, mainly tabular but three-dimensional product, obtained by means of an embossing die intended for processing a relatively soft and tabular end product consisting of a plurality of 'hinged parallelograms', which are limited by lines of constricted material in such a way that tractive forces exerted thereupon cause the hinged parallelogram formation to behave like a pantograph, whereby on the primary volume increase resulting from the embossing process a secondary volume increase is overlaid by stretching.

Description

Process for making a relatively soft product, as well as the product itself

The invention relates to a method for producing a relatively soft, essentially flat, but three-dimensional product, and to a corresponding product itself. Such products, as a whole flat products, are usually increased in volume by an embossing process. This increase in volume can influence the appearance on the one hand and the technical properties on the other. If, for example, a tissue or similar paper product is embossed, this can improve the touch properties in addition to an improved appearance. In addition to these touch properties, the conversion of the starting product by embossing can also

Improve the absorption properties of the product. A wide variety of materials are suitable for the method and the product according to the invention, for. B. With regard to paper: tissue (creped and uncreped, wet laid, one or more layers), cotton wool; with regard to textiles: all soft textiles, fabrics, so-called "non-wovens" (eg drained), textile laminates; with regard to plastics: all soft plastics as film or fiber composite; regarding leather: all soft leather; with regard to metal: thin metal foils, especially aluminum foils. A wide variety of embossing methods are possible for embossing, as are already known to the person skilled in the art.

In view of the known methods, the invention is based on the problem (object) of creating a product of the type mentioned at the outset, which has an increased degree of improved appearance and / or touch properties when using the simplest means.

This problem is solved by a method for producing a relatively soft, essentially flat, but nevertheless three-dimensional product with the following production steps:

a) converting a relatively soft, essentially flat starting product by embossing a three-dimensional pattern which produces a primary increase in volume compared to the starting product; and

b) stretching this intermediate product obtained by embossing the starting product essentially in the direction of its large area extension to produce a superimposed, secondary volume increase compared to the intermediate product.

It is to be regarded as a surprise that an embossed intermediate can be improved in a particularly simple manner with regard to secondary volume increase, at least in terms of appearance and touch properties, if the embossed intermediate is subjected to a stretching process.

This secondary volume increase has a special effect as a superimposition of the volume increase caused by the embossing if the embossing pattern of the Intermediate product is formed from a large number of interconnected parallel parallelograms and the stretching is carried out as an optimum approximately in a direction that runs diagonally through the parallelograms and in particular through diagonally opposite articulation points, which of course are not real articulation points in the mechanical sense, but rather from the The result of the embossing process is that lines of compacted material cross each other and limit the parallelograms, which in a network act like a pantograph when the stretching forces are applied.

An increase in volume is understood to mean bulges of the largely flat starting product resulting from embossing, so that primarily an increase in volume takes place in the direction perpendicular to the large area of the starting product.

The expression "relatively soft" implies the need to be able to carry out an embossing operation at all. However, the expression also includes a deformability of the product in such a way that permanent stretching can be achieved by the stretching process as well as by the stamping process. The product should also have a certain and, if necessary, a particular flexibility and softness, depending on the application and whether the appearance or the touch characteristic is in the foreground.

The problem is also solved by a relatively soft, large-area, but three-dimensional product with a three-dimensional embossing pattern and a secondary volume enlargement superimposed on this embossing pattern as an inherent primary volume increase. The secondary volume increase can be arranged convex and on the convex side of the embossing pattern forming the primary volume increase. But it can also be concave. The embossing pattern does not have to be, but can be symmetrical.

The secondary increase in volume can be achieved in a particularly favorable manner if the embossed individual shapes in plan view have a shape which is located between the shape of a circle and that of a square or rectangle. However, there should be a clear deviation from the circular shape. For example, the embossed pattern generally forms a diamond pattern.

Appropriately, lines are formed in the embossed pattern lying essentially in one plane, which are connected to one another and four of which form an "articulated parallelogram" and many such articulated parallelograms are networked with one another, as already mentioned above in connection with the method has been. These lines cross each other, and similar to a pantograph, the crossing points form articulation points if the stretching forces mentioned are applied in the correct way. The lines between these crossing points (hinge points) can be straight, but do not have to be straight. You can take a curved course, such as with a so-called oriental or Venetian pattern. Behavior like a pantograph is essential if appropriate stretching forces are applied.

The relatively soft, large-area, but three-dimensional product is obtainable in a special way by a flat, three-dimensional intermediate product provided with an embossing pattern forming a primary volume increase, which is produced with an embossing tool, which intermediate product is stretched essentially in the direction of the large-area product Extension given a permanent secondary volume increase superimposed on the primary volume increase becomes. This means that the design of the embossing tool has a significant influence on the superimposed, permanent secondary volume increase caused by stretching.

The use of a so-called "female" embossing tool, which has recesses into which the material of the flat starting product is pressed for the permanent primary volume change, is particularly expedient. In connection with this, the embossing tool has webs which are interconnected between the recesses and which, together with the recesses, give the intermediate product an embossing pattern by limiting the recesses of corresponding bulges of material pressed and thus stiffened by the webs, which lines are particularly favorable Form by the "female" embossing joint parallelograms, which are interconnected in such a way that this network acts like a pantograph when applying opposite stretching forces in the direction of the large surface area and essentially in the diagonal direction of the joint parallelograms of the intermediate product. Accordingly, the parallelogram should be oriented in the machine direction if the stretching is done in the machine direction.

The secondary volume expansion can be achieved particularly effectively if the side walls of the recesses in the embossing tool run on all sides at a certain acute angle, starting from the tool surface. This angle should preferably be not less than about 40 and in particular not less than about 60 °. This angle is 65 ° in a particularly favorable manner.

The number of individual shapes per square centimeter also has a positive influence on the formation of the secondary volume increase. So this number of individual forms per square centimeter 0.5 to 6 and in particular 1 to 2.5.

The dimension of the recesses of the embossing tool also has an influence on the formation of the permanent secondary volume increase by stretching. The ratio of the depth of the recesses to the width can thus be 0.1 to 0.5 and in particular 0.2 to 0.3.

The recesses in the embossing tool can have staggered side walls in such a way that, starting from the tool surface, a plurality of wall sections are lined up in the depth of the recesses, and the acute angles which the wall sections form with respect to the tool surface are smaller from wall section to wall section.

The webs between the recesses of the embossing tool can preferably have a width of 0.5 mm to 3 mm and in particular of 1.2 mm to 2.2 mm. A profile can also be provided in the webs mentioned and in particular a number of recesses formed along the same can be provided in the webs. As a result, bulges form in the embossed lines of the product as additional volume increases.

The invention is explained in more detail below with the aid of some training examples shown purely schematically in the drawings. Show it:

La the schematic top view of an embossing pattern of a tissue product;

FIG. 1b shows a top view of an embossing tool for producing the product according to FIG. La;

1c shows a partial sectional view along the line AA in FIG. 1b; 2a to 2c views similar to FIGS. 1a to 1c, but with a different design;

3a to 3c views according to FIG. La to lc or FIGS. 2a to 2c, but with a further, differently designed pattern;

4 shows a schematic sectional view of an embossing pattern bulge with a single side wall section;

5a to 5c show different sectional views of an embossing pattern bulge with multiple side wall sections;

Fig. 6a is a schematic plan view of a

Embossed pattern bulge from the convex side in the unstretched state;

Fig. 6b is a diagonal sectional view through the

Bulge with the representation of a primary volume increase caused by the embossing;

7a, 7b, 7c, 7d a representation similar to FIGS. 6a and 6b, but after the stretching process, with FIGS. 7b, 7c, 7d a secondary volume increase caused by the stretching being recognizable as a superimposition of the primary volume increase;

Figure 8a is a view of the pattern of the final product of Figure 1 ("diamond");

8b shows a view of a toilet paper roll with the pattern according to FIG. 8a; FIG. 9a is a view of the pattern of the end product according to FIG. 2 ("oriental");

FIG. 9b shows a view of a toilet paper roll with the pattern according to FIG. 9a;

FIG. 10a is a view of the pattern of the end product according to FIG. 3 C-"pillow-shaped"); and

10b is a view of a toilet paper roll with the pattern of FIG. 10a.

In the drawings, for example Fig. La and lb, matching patterns are shown, but in such a way that Fig. La would be regarded as the embossed pattern based on the tool pattern (reverse view) and Fig. 1b as the corresponding pattern of the embossing tool itself. Since the product is produced by the embossing tool in particular with regard to the intermediate product, only the embossing tool is described below with reference to the three exemplary embodiments, since this also identifies the product as such.

In Fig. La to lc a pattern is shown, which can be referred to as a "diamond" pattern. Compared to reality, the pattern according to FIGS. 1 a and 1 b corresponds to a scale of 2: 1 and the individual representation according to FIG. 1 c corresponds to a scale of 10: 1. This also applies to FIGS. 2 and 3.

The embossing pattern of the embossing tool comprises webs 1, four of which each form a square or parallelogram, which are lined up in such a way that a network results from the webs. Recesses 2 arranged in series in the web 1 can be provided, which represent small bulges in the embossed intermediate product. However, these recesses do not necessarily have to be present. There is a large recess between the webs 3, which is formed by staggered side walls 4a and 4b. The side walls 4a form an angle cc with the tool surface 5 and the side walls 4b form an angle β which is smaller than the angle α.

The large recess 3 has a depth c with respect to the side wall 4a and a depth d with respect to the side walls 4a and 4b. According to a preferred embodiment, the dimensions mentioned have the following values:

a: 1 mm b: 6 mm c: 1 mm d: 1, 7 mm α: 65 ° e: 0.25 mm.

2b shows an embossing pattern corresponding to a so-called "oriental" pattern, the machine direction being indicated by the arrow M. The scale ratios are the same as in FIG. 1, which also applies to FIG. 3. The following dimensions are relevant here:

a 1 mm b 6 mm c 1 mm d 1, 7 mm f 8 mm g 13, 6 mm h 1 mm α 65 °.

Fig. 3 shows a "pillow" -shaped pattern, which pattern can be offset by an angle γ of 1.5 ° to the machine direction. With such an offset, the repeat height is approx. 183.21 mm, ie 18.5 figures per repeat. The following values result for the measurements:

a: 1 mm b: 6 mm c: 1 mm d: 1, 7 mm e: 0, 25 mm i: 1.4 mm in diameter k: 7 mm α: 65 °.

If, for example, a tissue paper is embossed in the form of a pattern as a starting product with the respective embossing tools, as shown in FIGS. 1, 2 and 3, a rubber roller presses the tissue paper against the webs 1 and into it Recesses 3, whereby the starting product is embossed in such a way that the material is compressed and stiffened in the region of the webs and bulges 6 are formed in the region of the recesses 3, as can be seen, for example, from FIG. 6. The embossed edge areas are provided with the reference number 7 there. These are specifically referred to here as embossed lines. According to the network of webs, these lines form parallelograms, as shown in FIG. 6a, the crossing points of the lines being to be regarded as articulation points, as can be seen, for example, from FIGS. 3a and 3b. With regard to the networking of joint parallelograms, the entire pattern can behave like a mechanical pantograph if, in accordance with the illustration in FIG. 7a, stretching forces S are applied which, according to a pantograph movement, lead to a narrowing of the parallelogram, as is shown by the arrows P is indicated. The bulge 6 forms a primary increase in volume during the embossing process, and a secondary increase in volume 8 superimposed on this by the stretching process by means of the stretching forces S, which is indicated by the arrow V in FIGS. 7b, 7c, 7d. there 7c and 7d, the secondary volume increase is a superimposed fold.

With regard to the recesses of the tool, FIG. 4 shows a schematic illustration of an exemplary embodiment with individual side walls and an associated angle α. 5a shows a sequence of staggered side walls 4a, 4b with corresponding angles α and β, the angle β being smaller than the angle α, measured to the tool surface. According to FIG. 5c, it is also possible to provide first side wall sections 4a, which is followed by a curved surface 4d like a dome.

Some examples are given below to illustrate the invention.

Example 1: A two-ply tissue paper web was drawn off from an initial roll and fed to an embossing mill. The two-ply tissue paper had a basis weight of 21.9 g / m ² and a width of 50 cm. The tissue paper consisted of 100% cellulose pulp. The embossing plant consisted of a steel roller and a rubber roller. The steel roller had a diameter of 198 mm. The rubber roller had a diameter of 174 mm with a rubber thickness of 17 mm and a rubber hardness of 33 shore. The female embossing recesses had a dimension according to FIGS. 1b and 1c of the drawings in connection with the associated description. The embossing pressure between the rolls was 9420 N / m.

The product embossed with this embossing unit was then fed to a drafting system (all in one device) and stretched there across the width with a stretching force of 30 N / m. The aforementioned secondary volume increase occurred, which was superimposed on the first volume increase resulting from stamping. Compared to the starting product, there was an increase in volume of 21.4%. The strength in the machine direction decreased by 17.6% compared to the starting product (ie the flexibility in this direction increased). The elongation at break decreased by 12.3% compared to the starting product and the strength in the cross-machine direction by 36.8%.

After stretching, the product was wound up as sections spaced in lengths by perforation on a roll of toilet paper. This roll had a diameter of 123.2 mm and a compactness of 635 cm x 10 ^{~ 3} .

The aforementioned strength in the machine direction corresponds to the tensile stress in the machine direction until it breaks. The two-ply tissue paper or the finished product was cut into 76 mm wide samples and then aligned in the machine direction. The samples were clamped between two clamps of a tensile tester. The clamps were 51 mm apart and the sample was pulled apart at 250 mm per minute. As a result, the peak force was recorded in N up to the break. A similar procedure was used in the cross-machine direction. The increase in volume was measured in such a way that sheets ten times cut from the starting material and sheets of the end product placed five times on top of one another were placed in an electronic thickness measuring device with a foot pressure of 2.9 kPa. The results were recorded in thousandths of a mm.

The basis weight was determined in such a way that ten sheets, which had been cut from the starting material, or five sheets of the two-ply end product were again placed on one another as squares of 10 × 10 cm. The sample was then weighed and the result multiplied by 10 and then recorded as kPa. The diameter of the finished toilet paper roll was measured so that a calibrated tape was wrapped around the circumference of the finished roll to indicate the diameter.

The compactness or winding hardness of the finished toilet paper roll in cm x 10 ^{~ 3} was measured as follows. The finished toilet paper roll was held by a rigid rod that was pushed through the core. Then a tester loaded with a light load was placed on the circumference of the roll. After a set-up time of approx. 15 seconds, the measuring device was read zero. Then a heavier weight was put on and after stabilization after 15 seconds a second reading was taken. The difference in readings was recorded as the compactness of the roll and was measured in thousandths of a cm. Accordingly, the compactness was 635 cm x 10 ^-3 .

Example 2: The procedure is basically the same as in example 1, but with the following changes. The embossing tool corresponded to the information shown in FIGS. 2b and 2c. The diameter of the steel roll was 191 mm.

The decrease in strength in the machine direction (increase in flexibility) compared to the starting product was 22.9% in the finished roll and the corresponding decrease in strength in the transverse direction was 39.3%. The increase in volume increase was 12%. The finished roll had a diameter of 123.7 mm and a compactness of 622.3 cm x 10 ^"3 .

Comparative example: A comparative example was realized with a sample according to FIG. 1. However, the diameter of the steel roller was 197 mm. The angle α was 38 °, the value b was 7.2 mm and the value d was 1.3 mm. This only resulted in a volume increase of 1.7%. The The diameter of the finished toilet paper roll was 120 mm and the compactness was only 503 cm x 10 ^-3 .

Claims

claims

1. Method for producing a relatively soft, essentially flat, but three-dimensional product with the following production steps:

b) Stretching this intermediate product obtained by stamping the starting product essentially in the direction of its large area extension to produce a superimposed, secondary volume increase compared to the intermediate product converted by stamping.

2. The method of claim 1, according to which the embossing pattern of the intermediate product is formed from a plurality of interconnected "joint parallelograms", and that the stretching takes place approximately in a direction that runs diagonally through the parallelograms.

3. Relatively soft, large-area, but three-dimensional product with a three-dimensional embossing pattern and a secondary volume enlargement superimposed on this embossing pattern as an inherent primary volume increase.

4. The product according to claim 3, wherein the secondary volume increase is arranged convex and on the convex side of the embossing pattern forming the primary volume increase.

5. Product according to claim 3 and / or 4, wherein the embossing pattern is substantially a symmetrical embossing pattern.

6. Product according to at least one of claims 3 to 5, in which in the embossing pattern the embossed individual shapes have a shape in plan view, which is formed between the shape of a circle (clearly away from the shape of the circle) and that of a square or rectangle.

7. The product of at least one of claims 3 to 6, wherein the embossed pattern is generally a diamond pattern.

8. Product according to at least one of claims 3 to 7, in which in the embossed pattern between the individual shapes substantially formed in one plane embossed lines are formed which are interconnected and four of which form a kind of parallelogram and many such parallelograms networked with each other are.

9. Relatively soft, large-area, but three-dimensional product, obtainable by a flat, three-dimensional intermediate product provided with an embossing pattern forming a primary volume increase, which is produced with an embossing tool, which intermediate product is stretched essentially in the direction of its large-area extension a permanent secondary volume increase superimposed on the primary volume increase is given.

10. Product according to claim 9, for which the embossing tool has recesses into which the material of the flat starting product is pressed for the permanent primary volume change.

11. Product according to claim 9 and / or 10, for which the embossing tool has webs connected to one another between the recesses, which together with the recesses give the intermediate product an embossing pattern in which corresponding recesses of lines embossed by the webs are pressed together and thus stiffened Material are limited, which lines form parallelograms that are interconnected in such a way that this network acts like a pantograph when opposing stretching forces are applied in the direction of the large surface extension and essentially in the diagonal direction of the parallelograms of the intermediate product.

12. Product according to at least one of claims 9 to 11, for which the side walls of the recesses of the embossing tool extend from the tool surface on all sides at a certain acute angle.

13. Product according to claim 12, for which said angle is not less than about 40 ° and in particular not less than about 60 ° and in particular 65 °.

14. Product according to at least one of claims 9 to 13, for which the recesses have staggered side walls, by starting from the tool surface a plurality of wall sections in the depth of the recesses are lined up and thereby the acute angle, the form the wall sections to the tool surface, is smaller from wall section to wall section.

15. Product according to at least one of claims 9 to 14, for which the number of individual shapes per square centimeter is 0.5 to 6 and in particular 1 to 2.5.

16. Product according to at least one of claims 9 to 15, for which the ratio of the depth of the recesses to the width is 0.1 to 0.5 and in particular 0.2 to 0.3.

17. Product according to at least one of claims 9 to 16, for which the webs between the recesses have a width of 0.5 mm to 3 mm and in particular from 1.2 mm to

Have 2.2 mm.

18. Product according to at least one of claims 9 to 17, for which the webs have a profile and in particular a series of recesses formed along the webs.

19. Product according to at least one of claims 3 to 18, wherein the material used is tissue.