FI56414C - REFERENCE FORM OF A FIBER MACHINERY FRAMSTAELLNING AV TUNNA OCH BOEJLIGA ARK- ELLER BANFORMIGA FIBERMATERIALER - Google Patents

Description

ISa ^ Vl ΓβΊ ANNOUNCEMENT pry, I 4 WA lBJ (11) UTLÄGGNINGSSKRIFT 56414

MmtS C (45) Patent granted 10 01 1980 / Patent meddelat (51) Kv.lk.Vlnt.CI. · D 21 L 3/00 D 21 H 5/26 FINLAND —FINLAND (21) P »tenttlh» k «mu «—P» t * nun * öknlng 305/70 (22) Hakcmitpllvl - Anieknlngtdag 04.02.70 (23) AlkupJUvl - Giltlgheadaj 0 ^ .02.70 (41) Tullut fulklMktl - Bllvlt offantllf 05.08.70

Patented and registered. NihovUcip ^ on moon * *

Patent and registration authorities An * ök »n utligd och utl.ikrtften publkand 28.09.79 (32) (33) (31) Pyydatty« tuolkwis — Btglrd prlortut 04.02.69

England-England (GB) 5943/69 Proven-Styrkt (71) Karl Kristian Kobs Kr? 5yer, Vestre Kongevej 80, 8260 Aarhus-Viby, Denmark-Danmark (DK) (72) Torben Borup Rasmussen, Äbyhöj, Denmark-Danmark ( DK) (74) Oy Kolster Ab (54) Method for the production of thin and flexible sheet-like or web-like fibrous materials - Förfarande för framställning av tunna och böjliga ark- eller banformiga fibermaterialer

The object of the cooking is a method for producing thin and flexible sheet-like or web-like fibrous products, in which a gas stream containing independent organic, simple natural fibers is passed through a gas-permeable molding surface, whereby a fibrous layer is formed on it.

Fibrous materials prepared in this way have a tendency to delaminate, i.e. to decompose into different layers, because it is difficult to cause the binder to penetrate the fibrous layer. Attempts have been made to reduce this delamination pattern by impregnating the fibrous material with large amounts of binders.

However, this technique results in the fibrous materials becoming rigid, the manufacturing costs being greatly increased, because Eidos is a relatively expensive component of these materials.

It is an object of the present invention to provide a product which has a reduced tendency to delaminate without the use of large amounts of binders.

2 56414

The object is achieved by the method according to the invention, which is characterized in that the moisture content of the fibrous layer is adjusted to 6-15 by weight-96 after its formation and that the fibrous layer is embossed at a temperature above 100 ° C before it is glued.

When the above-mentioned quality fibrous material is wet-hot embossed, the organic natural fibers used deform and the contact areas at the intersections between the fibers increase considerably. This results in a capillary effect that greatly increases the absorption capacity of the fibrous material. In addition, deformation in the contact areas of the fibers increases the strength of the fibrous material.

As a result of the increased absorbency, the penetration of the binder into said areas, i.e. the contact areas, increases, whereby the effect of the binder is optimal compared to the cold-patterned fibrous material in the cold.

This manifests itself in an increase in the breaking length of the fibrous material. In the cold, the breaking strength of the interest-patterned fibrous material gradually increases as the amounts of binder increase to a binder content of about 50%, after which the breaking length decreases. In wet heat, the breaking strength of the interest-patterned fibrous material increases quite rapidly to a binder retention of about 30% and then begins to decrease. However, at a binder content of about 30 μm, the breaking length is considerably more buoyant than the breaking length of a cold-embossed fibrous material having an optimal binder content of about 30 μm.

Thus, when applying the method according to the invention, the same strength can be achieved by using much less binder than has previously been possible. As mentioned above, the total moisture content of the fibrous layer must be at least 6 Experiments have shown that the breaking length increases significantly with increasing moisture content to about 6% and that the breaking length continues to increase with increasing moisture content from about 13% to total moisture content. upwards no longer increase the break length.

Increasing moisture content requires the use of ever-increasing amounts of power to dry the product, and therefore it is generally not desirable to increase the moisture content of the fiber layer to a value greater than 13%.

As mentioned above, the heel pattern temperature must be above 100 ° C. Thus, it has been found that when performing the rate pattern at temperatures below 100 ° C, this does not achieve an increase in the breaking length. At 100 ° C, on the other hand, the break length increases suddenly, and this break length increases with increasing temperature. Because cellulosic fibers change color at temperatures of about 260 ° C, it is not normally desired to use such high temperatures. Especially popular with normal cellulose fibers

3,564U

the heel pattern temperature is about 250 ° C, provided that the heel pattern rate is suitably adjusted to this temperature.

The invention is explained in more detail below on the basis of some examples: A. Heel patterning of a fibrous sheet

The experiments mentioned below were performed to intentionally illustrate the effects of rate-patterning temperature, rate-patterning rate, rate-patterning pressure, and product moisture content on the breaking length.

The breaking length is calculated from the following equation B = --- n x g x b where B = breaking length in meters; P = sum of breaking loads in kilograms; n = number of experiments; g = sheet weight in grams / m; b = width of the test piece in centimeters.

A pair of heel-patterned rollers consisting of a steel heel-patterned roller and a smooth rubber roller were used in these experiments. The diameter of the steel roll was 240 mm and the length 400 mm. This heel-patterned roll was heated by means of electric heating elements with a total power of 16 kilowatts, which allowed the roll temperature to be set to the desired value, up to 350 ° C. The rubber roller had a diameter of 100 mm and a hardness of 75 degrees shore.

The heel-patterned pattern used corresponded to a wing pattern in which the distance between the heel-patterned areas was 1.4 mm and the width of the heel-patterned areas was 0.3 mm.

All experiments were performed on specimens 18 cm long and 2.5 cm wide. In those cases where the specimens were wetted, wetting was performed using an air jet nozzle.

Based on the results obtained, curves were drawn showing the relationship between the length of the break and the varying factors.

Figure 1 shows the relationship between the breaking length of the fibrous sheet, the temperature and the moisture content when the rate of patterning, the pressure of patterning and the weight of the fibrous sheet were kept constant. The heel patterning speed was 75 m / min. the press

O

The pressure was about 170 N / cm and the weight of the sheet was 70 g / m 2. It can be seen from Figure 1 that the increase in breaking length at temperatures up to 100 ° C was small, regardless of the moisture content of the sheet. By using a moisture content of $ 6.6, the breaking length increases rapidly after 100 ° C, and an even greater increase is achieved up to temperatures of about 260 ° C. A curve showing the breaking length of a sheet with a moisture content of $ 6.6 indicates that the curve flattens at about 160 ° C. This is due to the fact that most of the water has evaporated in the temperature range of 100-150 ° C, and that the amount of water present at about 160 ° C is so small that no further deformation of the fibers takes place.

Figure 2 shows the breaking length as a function of the heel pattern rate and moisture content, whereby the heel pattern temperature and the heel pattern pressure are kept constant. It can be seen from Figure 2 that at low rates of embossing, the maximum break length is reached when embossing fiber products with a relatively high moisture content.

Figure 3 shows the relationship between cut length, heel pattern pressure and temperature when the moisture content is kept constant. It can be seen from Figure 3 that the strength does not increase significantly when a roller pressure of about 170 N / cm is used.

Figure 4 shows the break length as a function of moisture content and heel pattern temperature. It can be seen from this figure that regardless of the high patterning temperature used, the breaking length does not substantially increase up to a moisture content of about 6%. When the total moisture content is in the range of $ 6-10, the breaking length is significantly increased when interest patterning temperatures between 120 and 250 ° C are used. With a moisture content above about 12, the strength increases only slightly. Instead, the product becomes stiff and requires relatively large amounts of power to dry it. As mentioned above, the increase in strength due to permanent deformation when the wet fibrous sheet is hot embossed is explained. When a fibrous sheet is embossed with cold rollers, only the fibers collapse, and the fibers, due to their flexibility, tend to return to their original shape after the embossing.

B. Gluing of heel-patterned fibrous sheets

As a result of the permanent deformation which mainly takes place around the points of contact between the fibers and which increases the areas of contact, a considerable capillary effect is achieved in these areas. This is due in part to the fact that the air between adjacent fibers, which prevents the binder from penetrating, is compressed.

Figure 5 shows the strength of heel-patterned and glued fibrous sheets, and this figure shows the breaking length as a function of the amount of binder, this amount being expressed as a percentage by weight of the sheet-like material. In the experiments performed, the moisture content before the heel patterning was 10.7 / &> and the heel pattern pressure was about 170 N / cm for the heel patterning of a sheet-like material at a speed of 75 m / min with a sheet-like material weight of 70 g / m. Acrylic latex was used as a binder at a concentration of 23% (based on dry matter). The binder was applied by means of an air jet nozzle.

Curve 1 in Figure 5 shows the results obtained by examining a fibrous sheet material which was heel-patterned at 250 °. ..

o in the temperature of 5,56414, and curve 2 shows the results obtained under the same conditions, except that the fibrous product was interest-patterned at 15 ° C.

Figure 5 shows that the breaking length increases as the amount of binder increases to about $ 30. From this value, the breaking length begins to decrease. The tensile strength also increases with increasing amount of binder but the breaking length decreases due to the fact that the weight of the sheet-like material increases at a relatively higher rate than the tensile strength.

When a sheet-like fibrous material is embossed with cold rollers, the breaking length increases as the amount of binder increases to about 50%, whereby the breaking length begins to decrease. Comparing the two above-mentioned curves, it is clear that the maximum breaking length of the hot embossed product is considerably longer than that of the cold embossed product, and that the maximum breaking length of the hot embossed product is achieved with a binder content significantly lower than that of the cold embossed product.

It should be emphasized that the breaking length of the hot-patterned product without binder is considerably longer than that of the cold-patterned product.