Untitled record

<img file="AT349429B_D0001.tif" />

AUSTRIAN ® Class: 08 Β »062/40

PATENT OFFICE © Int.CE: D04H 001/54 © AT PATENT NOTICE © No. 349429 ® Patent owner: IMPERIAL CHEMICAL INDUSTRIES LIMITED

LONDON UNITED KINGDOM / UK © Subject: NONWOVEN UNO DEVICE TO WHICH

PREPARATION © Addendum to patent no.

© Elimination from:

@ 0 Registered on: 1975 04 28 »3234/75

Exhibition priority:

© 0 © Union Priority: UNITED KINGDOM / UK (Journal of Laws 1975 02 07

5282/75 CLAIMED

Beginning of the patent period: 1978 09 15

Longest possible duration:

t Issued on: 1979 04 10

Inventor:

© dependence:

© Pamphlets considered to delineate the prior art:

0E-0S2103619 US-PS3120449

Nr.349429

The invention relates to a nonwoven fabric comprising a thermally bonded material containing distributed

Nonwoven fabric, wherein it has on each side of the fabric patterns of thermally bonded areas, of which overlap at least some areas of the one side bonded areas on the other side of the fabric and the

Nonwoven material compressed between opposite parts of bonded areas and over its entire

Strength is glued.

Furthermore, the invention relates to an apparatus for producing a thermally bonded partially bonded nonwoven fabric in which a nonwoven fabric containing distributed thermally bondable material is passed through the nip between cooperating Kälanderwalzen, of which at least one is heated and which carry different patterns of protrusions on the lateral surfaces.

Many methods of producing bonded nonwoven fabrics have been proposed, such as the application of adhesives to the web or heat treatment when the web contains thermoplastic materials. In particular, it is known to apply a heat and pressure treatment for adhering limited areas of the web by passing it through the nip between calender rolls, at least one of which is heated and bearing ridges and depressions on its surface. If that

Textile material is calendered between the Walzenmänteln occur solid or primary bonds in separate sections of the textile material, which result in a partially bonded fabric. Of the pair of rolls used as calender rolls, either a roll or both rolls can carry arrays of ridges and depressions on their surfaces, in the first case the second roll being smooth. In the first case, the smooth roll, especially when heated immediately, often also causes less solid or secondary bonding in the remaining fabric where it is not exposed to full roll pressure. This coherent secondary bonding on one side of the fabric causes a stiffening. In the second case, where both rollers carry projections, it is known to arrange them in the form of peripheral rings or screws or longitudinal ribs, which can not intermesh. The calendering with such rollers causes a secondary bonding not on an entire fabric side, but only at those points where the fabric has come into contact with a survey only on one side of the fabric. However, this limited secondary bonding is achieved at the expense of the disadvantage that only a limited number of regular patterns of primary bonds can be made at those points where the peaks intersect each other as the rolls rotate.

By calendering a nonwoven between two rolls carrying bumps which are held exactly in contact with each other, any patterns of both primary and secondary bonds could be produced; but compliance with such an exact match is not feasible or possible at great expense if sufficiently large rolls are used for the production of wide nonwovens and sufficiently small bumps that give nonwoven fabrics with useful properties and attractive appearance.

The optimum physical properties and the appearance of the nonwoven fabric are directly or vice versa depending on the extent of the bond and therefore the obtained properties of a nonwoven fabric are the result of a compromise. Previously available nonwovens have not achieved the best combination of properties for all purposes, particularly as a textile material for garments, where properties approaching those of conventional woven and knitted fabrics and a pleasing appearance are desired. The known nonwoven fabrics generally carried a geometrically regular pattern of primary bonds, which is aesthetically uninteresting.

There has now been developed an aesthetically pleasing, partially bonded nonwoven fabric and a device for its manufacture, which solves or greatly reduces the various problems of excessive secondary bonding, limited patterning possibilities, poor appearance and technical feasibility. ₀

The invention therefore relates to a nonwoven fabric of the type described, which is characterized in that the pattern on at least one fabric side of discontinuous, spotted-like bonded areas and that the nonwoven fabric passing through glued areas vary in shape and size. O

The apparatus according to the invention for producing the nonwoven fabric is characterized in that the pattern on a roll of continuous projections and the pattern on the other roll of individual protrusions and in that the end surface centers of the simultaneously located in the gap individual protrusions of a roller to those closest in the nip contiguous projections on the other roller have different distances, so that bumps facing each other in the gap come to coincide to different degrees.

In a preferred embodiment of the invention, the stand-alone protrusions are on one side

Roller in rows arranged closed staggered and the rows inclined to the nip. This arrangement serves to break the regularity of the pattern in a second direction on the cloth surface, and eliminates the rattling in a rotation when using ring or helical projections

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- 3 of the rolls. Of course, if the interrelated jumps are longitudinal ribs, it is not possible that

Turn off rattling; by reducing the distance between the ribs and / or enlarging the

Roll diameter, however, it can be reduced.

By contiguous projection is meant a projection which extends substantially around the entire circumference or over substantially the full length of the roller. Such protrusions may, for example, take the form of circular or elliptical rings, screws or longitudinal ribs.

The cooperation of the protrusions on one calender roll with opposite protrusions on the other roll of the pair will be described hereafter for simplicity with reference to the nip. This is of course not a static condition and the split line continues to move as the 10 rolls rotate. In practice, when the rolls have a diameter of a few to 30 cm and more, the pressure in the gap is distributed at every instant over a certain circumferential width of the gap comprising a plurality of projections in the circumferential direction. In operation, therefore, the interaction of opposing projections may be more complicated than described here for the static situation and a gap having no width. Deviations in the relative position of the rollers due to play and other mechanical disagreements in the calender mechanism cause enlargements of the colliding areas of several opposing pairs of protrusions and reductions in the collision areas of some other opposing pairs of protrusions. The variations in the bond pattern resulting from such deviations remain substantially unnoticed as a result of the variation of the pattern inherent in a product according to the invention.

The distances of the centers of the individual projections from the longitudinal axes of the continuous projections are preferably in the range between zero and half the distance of adjacent contiguous projections, so that the rollers, regardless of their relative position, can not intermesh and the pattern of primary bonds formed in a nonwoven fabric has some large adhesions due to full contact of some end faces of protrusions and some only very small bonds due to only transient contact between other protrusions. This type of pattern of primary bonds results in an optically interesting structure of the textile material which is essentially not visibly changed by deviations of the relative position of the rolls.

Nonwovens suitable for the nonwoven fabric according to the invention may contain staple fibers, continuous fibers or mixtures thereof. Staple fiber webs are advantageously made by carding a pile of staple fibers or treating the fibers in a conventional blown process. Nonwoven webs can be made in a conventional blown process using an air jet to transport the fibers from their origin and spread on a perforated conveyor belt in a random array. The fibers can be electrostatically charged to aid in their separation prior to deposition on the conveyor belt.

A thermoplastic contained in a nonwoven fabric used in the nonwoven fabric of the present invention

Material may consist of particles dispersed in the web, or it may be in the form of distributed fibers having a lower softening or melting point than the remaining fibers of the web, or the web may be wholly or partly made of bicomponent fibers, one component of which is at least partially at the surface of the web Fibers is present and has a lower softening or melting point than the other component. The fibers of a nonwoven web may be natural or synthetic fibers or of linear organic polymeric materials, for example melt spinnable polyesters, polyamides and copolymers of these organic linear polymer groups, spun synthetic fibers.

In the apparatus according to the invention, both patterned rolls may be rigid, or one or both rolls may have inherent resiliency or limited flexibility to accommodate and compensate for small differences in pressure along the nip, in which case a back-up roll acting against the compliant roll may be required.

The stand-on protrusions forming the pattern of protrusions on a roller of a pair of calender rolls may have different shapes, for example, small points with flat or slightly curved faces and with a square, rectangular, circular or other cross-sectional shape, where 50 at the face is a few tenths or hundredths of a square millimeter measures. The projections can be produced on the roll shell by appropriate milling or etching. Contiguous protrusions about 0.1 to 1 mm wide are simply milled or knurled on a lathe or milling machine. If the pitch of the protrusions on the rollers is not equal, the different relative position of opposite end faces of protrusions can be achieved by selecting the size and pattern of the protruding protrusions. If the pitches of the projections are the same, twisting a pattern a small angle to another is the easiest way to achieve the different relative position of opposing projections. This measure also has the advantage that the pattern of primary bonds imparted to a nonwoven fabric can be changed radically simply by milling a pattern at a different angle of inclination.

- 4 No.349429

By applying a different relative position of opposing surfaces of projections according to the invention, the fixed or regular characteristic of the known methods

Patterns of intermittent bonds, wherein the bonds also have substantially regular size and shape, replaced by patterns of bonded areas, in particular primary bonds that are neither in shape nor size regular, the regular arrangement of the projections on each calender roll broken and patterned of the resulting bonded web is not recognizable. Therefore, the centroids of those bonded areas adjacent to each straight line across the nonwoven fabric have different distances therefrom. This compensates for variations in the relative position of opposing portions of protrusions on the rollers during their rotation due to play in the drive mechanism or other mechanical inconsistencies, by causing changes in the bonded areas in the overall irregularity of the bond pattern

Textile material with pleasing appearance and good grip and fall.

A nonwoven fabric according to the present invention exhibits on both sides patterns of strongly bonded regions which arise when opposite faces of protrusions in the nip fully meet, and patterns 15 of comparatively weakly adhered regions where the web has only come into contact with a heated projection on one side and the heat has been sufficient for melting together contacting fiber sections. Such weaker bonds may not be easily seen by the naked eye, but are easily detected under the microscope. For the sake of simplicity, the strongly bonded areas will be referred to as primary bonds and the weakly bonded areas as 20 secondary bonds. In addition, the nonwoven fabric is substantially completely unglued

Areas that have not come into contact with protrusions on one of the two rollers before. The visible differences between these three area groups on the nonwoven surface can be made clearer by superficial metallization of the nonwoven fabric.

In order to develop the optimum properties, in particular grip and fawn properties, a slight mechanical treatment of the nonwoven fabrics after bonding may be required, for example bending and folding, as occurs in rinsing or dyeing of the nonwoven fabric in strand form. Nonwoven fabrics of mixtures of certain fibers, in particular mixtures of synthetic polyamide or polyester two-component or one-component fibers, show excellent gripping properties even in the raw state immediately after bonding, without first having to be mechanically treated, which further processes such

If necessary, treat materials.

The invention will be explained in more detail with reference to the drawings. FIG. 2 shows a pattern of contiguous elevations on a calender roll in the form of a number of equidistant Umfengsringe, Fig. 3 a hergesteUtes by etching etched Pattern of 35 bumps on a calender roll, Fig. 4 one side of a nonwoven fabric according to the invention having the pattern of primary bonds obtained when the web passes through a pair of calender rolls, one patterned as shown in Fig. 1 and the other patterned as shown in Fig. 2, the patterns at an angle of 2 ° FIG. 5 shows a nonwoven fabric bonded between rolls according to FIG. 4, but bonded at an angle of 8 °, FIG. 6 shows a side of a nonwoven fabric which is connected between a roll according to FIG. 2 and a roll according to FIG. 3 FIG. 7 shows one side of a nonwoven fabric bonded between rolls according to FIG. 6 but bonded at an angle of 5 °. FIG.

In these representations, white areas in Figs. 1 to 3 surveys and in Figs. 4 to 6 primary bonds. All figures are representations essentially in natural size.

As the patterns of primary bonds of Figs. 4 and 5 show, the higher resolution of the line pattern of Fig. 2 becomes immediately apparent by using a larger angle of inclination. Figs. 4 and 5 are also the different bonding areas along each imaginary split line (the fabrication direction corresponds to the longitudinal direction of the paper) as they result from the different relative position of opposite projection / elevation pairs.

Fig. 6 shows a pattern of primary bonds of various areas obtained by selecting the respective roll patterns without using an inclination angle.

Fig. 7 illustrates the enhanced effect of the pattern selection of Fig. 6 along with the inclination of one pattern with respect to the other at a small angle.

The invention is further illustrated by the following examples, in which the crimp ratio results from stretched length - crimped length _χ10θ crimped length

Nr.349429

The wrinkle coefficient was determined by the method of Cusick, J. Text. Inst. 1968, 59, T 253, measured.

Some properties were in two directions, in the longitudinal or fabrication direction and in the

Transverse direction, measured; these are referred to as IR or QR in the following examples.

Example 1: A nonwoven fabric according to the invention was produced as follows:

Freshly spun sheath / core bicomponent fibers in which the shell is nylon 6 and the core 66 is nylon 66 in a ratio of 35: 65% by weight were partially stretched and made into a randomly laid nonwoven having a caliper by means of an air jet 0, 69 N / m² blown; the fibers had a tensile strength of 0.024 N / decitex, an elongation at break of 120% and a decitex of 4.

The web was then slit in the gap between 1 m 2, each heated to 200 ° C and calender rolls compressed under a nip pressure of 196 N / cm, the patterns of contiguous. single projections and intermediate recesses carried heat and pressure treatment at a speed of 7.5 m / min. The pattern of discrete protrusions on a roll corresponded to Fig. 3, with the end faces of each protrusion measuring 2.65 x 0.90 mm, having axial distances and longitudinal spacing of 1.28 mm, and the protrusions being 1.0 mm high. The roll diameter was 195 mm. The pattern of contiguous protrusions consisted of 0.73 mm high, 0.38 mm wide at the face and spaced 1.42 mm apart. The second roll also had some compliance to equalize the pressure in the gap by being formed by a 13 mm thick steel tube with an outer diameter of 127 mm. The pattern of discrete protrusions on the upper roll was aligned axially and circumferentially, the ridges on the lower roll being axially parallel.

The conditions prevailing in the gap caused tackiness of the skin component of the fibers while leaving the core component substantially unaffected, and upon cooling, primary and secondary bonds formed between adjacent fibers, the pattern of primary bonds corresponding to Figure 6.

The product looks pleasant, is excellent after washing and has the properties given below before and after a simple wash at 60 ° C in water:

<td>property</td><td>rawness</td><td>After washing</td>

<td>Mass g / m²</td><td> 73</td><td> 84</td>

<td>Crease coefficient (%)</td><td> 73</td><td> 27</td>

<td>Breaking strength (N / g / cm) LR</td><td> 3492</td><td> 2806</td>

<td>QR</td><td> 4032</td><td> 3787</td>

<td>Elongation at break (%) LR</td><td> 61</td><td> 48</td>

<td>QR</td><td> 75</td><td> 74</td>

<td>Tear strength (N / g / m²) LR</td><td> 0, 373</td><td> 0, 304</td>

<td>QR</td><td> 0, 285</td><td> 0, 265</td>

Example 2: A nonwoven fabric according to the invention was produced as follows:

Two-component polyester fibers having a core of polyethylene terephthalate [intrinsic viscosity, (IV), 0.65, measured at 25 ° C. in a solution in o-chlorophenol] and a shell of a 10 mol% ethylene isophthalate / terephthalate copolyester [(IV ), 0.55J, the components being in a ratio of 2: 1 (core: Envelope) were melt spun, stretched to a decitex of 3.3, mechanically crimped to 3.5 crimps / cm at a crimp ratio of 34 and cut into 50 mm long pieces in a stuffer box. The staple fibers thus produced were mixed with an equal weight 35 staple fibers of polyethylene terephthalate, (IV), 0.63, 3.3 decitex, 50 mm in length, 3.5 crimps / cm and crimp ratio of 34%, to form a nonwoven having a mass of 142 g / m² processed by means of a conventional blowing device. The fleece was lightly needled for compression, u.zw. with 36 Gauge 5 hook needles, which were arranged arbitrarily in a needle board and penetrated 4 mm deep into the fleece. The nonwoven was passed through the needle wheel at a speed of 46 pin pricks / cm² guaranteed.

The web was then calendered between pattern heated calender rolls, heated to 195 ° C and compressed under a nip pressure of 304 N / cm, as used in Example 1, at a speed of 3 m / min.

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The partially bonded textile material has the following properties in its raw state:

<td>Mass (g / m²)</td><td></td><td> 142</td>

<td>Crease coefficient (%)</td><td></td><td> 79</td>

<td>Breaking strength (N / g / cm)</td><td>LR</td><td> 589</td>

<td></td><td>QR</td><td> 1354</td>

<td>Elongation at break (%)</td><td>LR</td><td> 19</td>

<td></td><td>QR</td><td> 62</td>

<td>Tear strength (N / g / m²)</td><td>LR</td><td> 0,118</td>

<td></td><td>QR</td><td> 0,108</td>

Example 3: Another embodiment of the nonwoven fabric according to the invention was produced as follows:

A lightly compacted nonwoven with a mesh of 133 g / m² was prepared as in Example 2 from a mixture of equal parts by weight of wool and polyamide bicomponent staple fibers of the composition according to Example 1 with a Decitex of 3.3, a length of 100 mm, 5.3 crimps / cm and a clogging ratio of 20%.

The web was then calendered at a speed of 3 m / min between two patterned rolls heated to 217 ° C each at a nip pressure of 304 N / cm. One roll carried a pattern as shown in FIG. 3 of stand-alone protrusions as described in Example 1, and the other a left-hand thread of 5.2 turns per cm and a substantially square cross-section with a face width of 20 0.32 mm. The second roll was a compliant steel cylinder with 127 mm OD and 112.5 mm ID.

The partially bonded textile material produced in this way has the following properties in its raw state:

<td></td><td>Mass (g / m²)</td><td></td><td> 133</td>

<td></td><td>Crease coefficient (%)</td><td></td><td> 77</td>

<td> 25</td><td>Breaking strength (N / g / cm)</td><td>LR</td><td> 1295</td>

<td></td><td></td><td>QR</td><td> 657</td>

<td></td><td>Elongation at break (%)</td><td>LR</td><td> 27</td>

<td></td><td></td><td>QR</td><td> 54</td>

<td></td><td>Tear strength (N / g / m²)</td><td>LR</td><td> 0, 015</td>

<td> 30</td><td></td><td>QR</td><td> 0, 735</td>

Example 4: Another nonwoven fabric according to the invention was produced as follows:

A lightly compacted fleece with a mass of 122 g / m² was as described in Example 2, from

Nylon 6 staple fibers having a decitex of 6.7, a length of 72.5 mm, 11.6 crimps / cm and a crimp ratio of 24%.

The web was then calendered between patterned rolls heated to a temperature of 200 ° C each at a speed of 3 m / min and a nip pressure of 304 N / cm. The lower compliant roller carried a pattern of ribs as in Example 1 and the upper roller with a diameter of 195 mm carried a close staggering arrangement as in Fig.l of parallelogram-shaped projections with dimensions of 3.22 and 0.84 mm in the circumferential and. Axialrichtung and a distance of 0.58 and 0.71 mm in the circumferential direction or axial direction, with the longer dimension of the elevations extending substantially at right angles to the roll axis.

The partially bonded nonwoven fabric has the following properties in its raw state:

<td></td><td colspan="2">Mass (g / m²)</td><td> 122</td>

<td></td><td>Crease coefficient (%)</td><td></td><td> 73</td>

<td> 45</td><td>Breaking strength (N / g / cm)</td><td>LR</td><td> 912</td>

<td></td><td></td><td>QR</td><td> 1010</td>

<td></td><td>Elongation at break (%)</td><td>LR</td><td> 16</td>

<td></td><td rowspan="2">Tear strength (N / g / m²)</td><td>QR</td><td> 34</td>

<td></td><td>LR</td><td> 0, 051</td>

<td> 50</td><td></td><td>QR</td><td> 0, 036</td>

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Example 5 A further variant of the nonwoven fabric according to the invention was produced as follows:

A lightly compacted fleece with a mass of 129 g / m² was prepared as described in Example 2, from a mixture of equal parts by weight of nylon 6 and nylon 66 staple fibers. The nylon 6 fibers corresponded to those used in Example 4 and the nylon 66 fibers had a decitex of 3.3, a

Length of 51 mm, 5 crimps per cm and a crimp ratio of 18%.

The web was sandwiched between patterned rolls as used in Example 4

Roll temperature and the same pressure in the nip and a speed of 3m / minkalandert. The partially bonded textile material produced in this way has the following properties in its raw state:

<td></td><td>Mass (g / m²)</td><td></td><td> 129</td>

<td>io</td><td>Crease coefficient (%)</td><td></td><td> 79</td>

<td></td><td>Breaking strength (N / g / cm)</td><td>LR</td><td> 1481</td>

<td></td><td></td><td>QR</td><td> 2070</td>

<td></td><td>Elongation at break (%)</td><td>LR</td><td> 29</td>

<td></td><td></td><td>QR</td><td> 34</td>

<td> 15</td><td>Tear strength (N / g / m²)</td><td>LR</td><td> 0,126</td>

<td></td><td></td><td>QR</td><td> 0, 067</td>

In the preceding examples, rolls having a length of 1 m each were used; However, other roll lengths and diameters or two rigid rolls may be used in the process of the invention.

The percentage of nonwoven web area occupied by primary bonds, calculated as the product of the area occupied by the bumps on each of the rolls, is given below:

<td>example</td><td>survey areas %</td><td>Area of ​​primary bonds%</td><td>Ratio of Elevation areas</td>

<td> 1</td><td>25 and 21</td><td> 5,3</td><td> 1,2</td>

<td> 2</td><td>25 and 21</td><td> 5,3</td><td> 1,2</td>

<td> 3</td><td>25 and 18</td><td> 4,5</td><td> 1,4</td>

<td> 4</td><td>46 and 21</td><td> 9,7</td><td> 2,2</td>

<td> 5</td><td>46 and 21</td><td> 9,7</td><td> 2,2</td>

High percentages of bonded surfaces usually result in stiffer nonwovens and lower percentages of bonded surfaces usually less coherent nonwovens. The same total area of ​​primary 25 bonds can also be obtained with rollers with equal areas or with rollers with unequal elevation areas, a greater secondary bonding on one side of the fabric and thus greater stiffness of the nonwoven fabric and at the same time less secondary bonding on the other side of the fabric and thus a reduced resistance of Nonwoven fabric against abrasion and pilling effect.

Therefore, it is preferred to use the same elevation surfaces which give nonwoven fabrics with balanced adhesion on the two fabric sides. However, a rigid adherence to a balanced bond means an unnecessary restriction of the pattern selection and turned out to be unnecessary. Various uses of the nonwovens also provide various criteria for their production. In general, the use of a pair of rolls is preferred whose total land areas are between 2 and 20%, in particular between 5 and 12%, and whose ratio of the land areas is less than 5: 1.

In the foregoing, methods using calender rolls for producing bonded areas in a nonwoven fabric are described. However, the less satisfactory compression of a web in sections between the platens of a press also falls within the scope of the invention; However, such alternatives are generally slow and less advantageous to perform.