FI59360C - FOERFARANDE FOER TILLVERKNING AV ABSORBERANDE OCH VAETSKETAETT LAMINAT - Google Patents

Description

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Patent · och r «fitterttyraltm '' Anaekan utia | rfoehwtUkrifMnpubUcmd 30.0U.8l (32) (33χ31) Fyyduqr wmbMww» i | W nor ** (71) Yhtyneet Paperitehtaat Oy, Paper product, 37601 Valkeakoski, Finland (Finland) 72) Antti Arjas, Valkeakoski, Jarmo Kivinen, Valkeakoski, Alpo Pollari, Valkeakoski, Finland-Finland (Fl) (7U) Ruska & Co.

The present invention relates to a method for producing an absorbent and liquid-tight laminate by passing a unitary plastic film in a molten state on one surface of an absorbent web material, e.g. are fastened to each other only in part of their surface, so that while the plastic film is still in the molten state, the fastening points are pressed against each other by means of an embossed press roll and an opposing smooth counter roll.

For example, in hospitals, in operating theaters, an operating textile and other hospital use require a product that is both absorbent and liquid-tight. Creped tissue paper has a suitable suction ability. The plastic film, on the other hand, is liquid-tight. If the plastic film is laminated to the paper so that the layers adhere to each other over its entire surface, the product becomes hard and rigid. Although the materials used are soft and descending, the jointed finished product is stiff. At the same time, the absorbency of the paper also decreases as the plastic penetrates the pores of the paper.

If the layers are attached to each other only in part on their surface, for example point-by-point, the softness and settlability of the finished product are maintained.

59360 2

In the past, the plastic film and the paper have been attached to each other by a point-like attachment so that the finished plastic film is glued to the paper.

According to DE patent publication 1,560,196, a method is known in which a uniform plastic film which is still in the adhesive state is guided, for example, on a substrate web of paper and fixed to it by pressing between rollers. By means of an annular groove rotating the press roll, a continuous strip is formed in the laminate in which the coating is not adhered to the base material.

It is known from FI publication 51519 to use a compression cylinder with an uneven surface, by means of which holes can be formed in the plastic film in the molten state.

In addition, it is known from U.S. Pat. No. 3 ΟβΟ 515 to "corrugate" a plastic film by means of an embossed roll.

It is known from GB 1 377 63 * 1 to laminate layers together by means of a layer which becomes adhesive under the influence of heat.

In this case, a heated press roll with point bumps is used. However, a disadvantage of this known method is that the protrusions are located relatively sparingly, whereby vibration which easily hinders the use of the laminating device is easily generated as the roll rotates.

The method according to the invention is mainly characterized in that a press roll known per se is used, the protrusions of which are separated from each other in all directions of the roll surface and that the pattern of the press roll is such that it has protrusions against the counter roll in all operating positions.

According to the invention, the production of the plastic film and its lamination to paper takes place in one step.

When the pattern of the press roll is such that it has protrusions against the counter roll in all operating positions, it is obtained that the roll does not tend to vibrate as it rotates.

For the finished product, it is essential that the layers adhere to each other only at compressed points. At the unsealed points, the plastic Silicon 3,59360 mi is detached between the surface layers. As a result, the entire original absorbency of the paper is retained even after lamination and that the product is softer, more settable, more comfortable and noisier than the same layers completely laminated.

No additives are used to join the layers, such as when gluing the layers together, and this is an advantage in hospital use. Not only for hospital use, the product is also suitable for other purposes as cloths.

The method according to the invention will be described in more detail below with reference to the accompanying drawings, in which Figure 1 shows a schematic side view of a device which can be used in the method according to the invention, and Figure 2 shows an example of a sealing surface.

The paper web 1 is led from the unwinding shaft to the nip 5 between the press roll 6 and the counter roll 7 of the laminator. From the nozzle 3 above, the molten plastic film 4 is led to the same nip. The temperature of the plastic is high enough to keep the plastic in the molten state, i.e. about 25 ° C to 340 ° C. The second paper web 2 is led from the opposite side of the film 4 to the nip.

The press roll 6 is coated with rubber, in which embossing has been obtained by milling. In this case, the layers to be laminated are pressed together and adhered together, but the pressing and adhesion take place only on a part of their surface. The height of the embossing can be, for example, 2 mm. It is advantageous to round the edges of the patterns so that the pressing operation is more gentle and the molten film is not damaged between the rolls.

The rubber of a patterned press roll should be somewhat harder than that of a non-patterned roll, with a suitable hardness range of 70 to 90 ° shore. A suitable line pressure on the press line between the press roll 6 and the counter roll 7 is 5 to 15 kp / cm, calculated per pressing part of the press line. According to the invention, the pattern of the press roll 6 must be such that, in all operating positions, the bearing surface of the roll has protrusions 10 opposite the counter roll 7 in order to prevent vibration. At the same time, care must be taken to keep the mounting surface to a minimum. Figure 2, in which the direction of travel of the lamination is indicated by an arrow, shows a pre-59360 indication of a suitable press roll pattern. Roll bumps 1 are indicated by reference numeral 10.

The support roller 8 prevents the rubber roller 6 from bending. A coolant, preferably water, circulates in the support roll 8, in the patterned press roll 6 and in the steel-jacketed cooling roll 7. The rollers are cooled to temperatures of about 5 to 50 ° C. The driving speed can always increase to 450 m / min. until.

The press roll 6 and the cooling roll 7 are preferably in a position relative to the nozzle 3 such that the plastic film 4 enters the nip 5 between the rolls substantially parallel to the common tangent of the rolls. In this case, the plastic does not stick to either paper web before the press nip.

On the way around the cooling roll 7, the product cools and the finished laminate 11 is passed from the top of the release roll 9 through the edge cut to be rolled.

Paper, preferably creped tissue paper, can be used as the web material to be laminated. The method is also suitable for laminating nonwovens and plastics, for example. The paper grades can, of course, vary, as well as their basis weights, for example weights of from 20 to 120 g / m 2 are suitable.

As the plastic, a suitable thermoplastic can be used, for example, polyethylene, polypropylene, polyamide or a polyolefin derivative to which metal ions have been attached and the resulting ionomeric plastic (SURLYN, registered trademark). Em. plastics can be used not only alone but also in various combinations. The amount of plastic can vary, for example, between 6-50 g / m 3, preferably 15-25 g / m 2. With suitable plastics or plastic combinations, the product is not only waterproof, but also bacterial, and resistant to steam, gas and radiation sterilization. One such plastic combination is polyethylene (5 g / m) + polypropylene (10 g / m).

Other plastics and plastic combinations are also possible.

The following is an example of the application of the method according to the invention.

A product having the following structure was prepared: p green creped distilled paper 45 g / m 2

Claims (2)

5,59360 2 dot sealed polyethylene film 15 g / m 2 white creped tissue paper 45 g / m The lamination was performed in the apparatus of Figure 1 using a press roll whose surface had been milled as shown in Figure 2. The lamination conditions were as follows: Plastic film temperature 3Q0 ° C Press roll and chill roll temperature 15 ° C Line pressure in the press nip (calculated per pressing part of the press line) 9 kp / cm Press roll hardness 8Q ° shore Travel speed 100 m / min. Width of the finished product 120 cm Machine width of the machine 80 - 160 cm The invention is, of course, not limited to the applications described above, but can vary considerably within the scope of the claims. A method of making an absorbent and liquid-tight laminate such that a unitary plastic film (4). guided in the molten state on one surface of the absorbent web material, for example paper (1, 2) or between two webs, the layers being attached to each other only on part of their surface so that the plastic film is pressed against each other and smooth counter roll (7), characterized in that a press roll (6) known per se is used, the protrusions (10) of which are separated from each other in all directions on the surface of the roll and that the pattern of the press roll (6) is such that it has a counter roll (7) protrusions in all operating positions (10). Method according to Claim 1, characterized in that a press roll (6) is used, the edges of the projections (10) of which are rounded.