EP0670773B1 - Laminated product made of cellulose wad - Google Patents

Abstract

The cellulose fibre tissue product (1), for use as handkerchief or napkin, is made by at least two ply cellulose pads (1a,1b). These are cut to required form and joined together along a peripheral border (3), by adhesive. The join presents a minimal resistance to delamination of 1 g/cm., the border area being less than 50% of total tissue surface area. The adhesive may be on the border of each ply, distributed as discontinuous spots (5). Alternatively, the borders may also be embossed, like waffles. The several ply may have differing composition.

Description

The invention relates to the field of sanitary and domestic paper; it relates to the production of laminated products composed of at least two plies or cellulose wadding sheet, in particular for the use of a handkerchief, napkin or other similar applications.

The handkerchiefs, generally packaged in cases, which are currently found on the market consist of several sheets of creped absorbent paper, also called cellulose wadding, superimposed, and held together by a mechanical connection at the periphery. This connection is obtained by an embossing operation, of the steel / steel or steel / paper type, according to which the sheets are passed between two cylinders meshing one on the other. One of the cylinders has reliefs on the surface and the other has corresponding cavities. The sheets are thus locally deformed into zones which constitute attachment points. A known embossing pattern consists of a multitude of spikes of small diameter and of low height tightened against each other linearly, or in both directions in the running direction and in the transverse direction. Another known pattern consists of fine edge bars. arranged in tight parallels. This bonding method is satisfactory when the grammage of the plies is not too high, of the order of 10 to 20 g / m ² , and when cellulose wadding is used without additives.

• le choix des motifs de gaufrage est limité il est guidé par la nécessité d'obtenir un accrochage entre les plis;
• il devient inopérant lorsque l'on souhaite utiliser des papiers présentant des caractéristiques différentes entre les plis, un allongement différentiel entre les plis par exemple ou bien une différence de composition fibreuse ou chimique. Ainsi l'addition d'un produit à effet déliant destiné à conférer de la douceur au papier n'est pas possible. On constate dans ce cas qu'il ne se produit aucun accrochage entre les plis.
• Le gaufrage donne un aspect rugueux qui se révèle désagréable pour une application en tant que mouchoir ;
     Le brevet GB-A-363 699 décrit un produit selon le préambule de la revendication 1 où les plis sont liés entre eux à la périphérie par compression de la matière fibreuse. L'expérience montre que ce mode de liaison n'est pas satisfaisant.

However, it has a number of drawbacks:

• the choice of embossing patterns is limited; it is guided by the need to obtain a hook between the folds;
• it becomes ineffective when it is desired to use papers having different characteristics between the folds, a differential elongation between the folds for example or else a difference in fibrous or chemical composition. Thus, the addition of a debonding product intended to impart softness to the paper is not possible. It is noted in this case that there is no snagging between the folds.
• The embossing gives a rough appearance which is unpleasant for application as a handkerchief;
  GB-A-363 699 describes a product according to the preamble of claim 1 wherein the plies are bonded together at the periphery by compression of the fibrous material. Experience shows that this mode of connection is not satisfactory.

The invention overcomes the drawbacks encountered on the products of the prior art by providing a product, such as a handkerchief or towel, produced by combining at least two individual plies, or sheets, of superimposed cellulose wadding, cut to size. desired and bonded together along a peripheral zone representing less than 50% of the total surface of the product, characterized in that said folds are bonded together along said zone so as to present a minimum resistance to delamination of 1 g / cm, the totality of the bonding surfaces between the plies being less than the surface covered by said peripheral zone.

The bonding is carried out by means of any adhesive product generally used in the field of sanitary and household papers to associate plies together. such as, for example, a polyvinyl alcohol in solution in an aqueous medium.

Preferably, the bonding is carried out along the four edges of the folds. It is assumed, for simplicity, that it is a rectangular or square format. The invention also includes the case where only two opposite edges are linked.

The bonding is carried out along a peripheral zone covering a strip the width of which can vary between a lower limit corresponding to sufficient resistance to delamination and an upper limit where the product would become too rigid. The linked area must represent less than 50% of the product: handkerchief or napkin. According to a particularly preferred embodiment, said zone represents between 30 and 40% of the total surface.

Along this zone, the bonding is carried out by a coating such that the entire bonding surface between the plies is less than the surface covered by the peripheral zone. This can be achieved by applying the adhesive to a plurality of small areas arranged in a linear pattern or at uniformly distributed points. A preferred method of binding is then in the latter case, that described in French patent FR-A-2 653 793 which makes it possible to ensure a uniform adhesive deposit in the bonding area without stiffening the sheet.

Admittedly, the Applicant is aware that it is already known to produce cellulose wadding towels where the folds are glued together. Thus, for example, US Pat. No. 3,673,060 describes a napkin produced in this way: two plies of cellulose wadding are placed one on the other so that their creping lines are parallel to each other, and are glued between them by points. It should be noted that this bonding is uniformly distributed over the entire surface of the towel according to close points; bonding limited to the edges of the sheet is not envisaged.

This type of product is not satisfactory insofar as the central, functional zone has a surface state and a flexibility more or less affected by the bonding.

The proposed solution makes it possible to produce handkerchief, towel or other similar products, that is to say in the form of individual sheets, having excellent resistance to delamination without being made rigid in the center. , that is to say in the functional area of use, or be likely to irritate the skin by bonding. Tests show that it is very easy to obtain products whose resistance to delamination is much higher than that of a mechanical bond of the prior art.

• Le nombre de possibilités offertes au fabricant pour décorer son produit et le rendre plus attractif est considérablement accru.
  Par exemple, il peut ne pas être gaufré à la périphérie il reste alors parfaitement plat et son conditionnement est plus facile ;
• On peut teinter la colle de manière à créer un effet de liséré plaisant à l'oeil.
  L'adhésif étant appliqué entre les plis, les pigments ne sont pas susceptibles de venir au contact de la peau ;
• On peut choisir un motif de gaufrage quelconque sans aucune contrainte sur la forme des reliefs, le motif du gaufrage et le type d'association : pointe/pointe ou emboîté ; on n'est pas lié par la nécessité d'assurer une liaison mécanique entre les feuilles par ce moyen.

Thus the proposed solution offers many advantages:

• The number of possibilities offered to the manufacturer to decorate his product and make it more attractive is considerably increased.
  For example, it may not be embossed at the periphery, then it remains perfectly flat and its packaging is easier;
• You can tint the glue to create an edging effect pleasing to the eye.
  The adhesive being applied between the folds, the pigments are not likely to come into contact with the skin;
• You can choose any embossing pattern without any constraint on the shape of the reliefs, the embossing pattern and the type of association: tip / tip or nested; one is not bound by the need to ensure a mechanical connection between the sheets by this means.

According to another characteristic of the invention, sheets having different fibrous and / or chemical compositions are combined by peripheral bonding.

According to a particular embodiment, a sheet incorporating an additive is added to increase the wet strength of the paper with at least one sheet without additive or else incorporating an additive to improve the softness. This results in a laminate complex combining properties that cannot be found together on a single-layer product.

According to another embodiment, we combine folds made with different pastes. For example, for a three-ply handkerchief, one can choose to make the central ply with pastes of lower cost than the cover plies, such as CTMP or bisulfite.

It is also certain that it is possible to incorporate therein or not chemical additives known to a person skilled in the art.

• La Figure 1 représente un produit, mouchoir par exemple, avec une zone de liaison périphérique des différents plis. Un coin a été délaminé pour montrer les plis.
• La Figure 2 représente une installation susceptible de permettre la réalisation d'un produit selon l'invention.
• La Figure 3 représente un détail de l'installation de la Figure 2.

Other characteristics and advantages will appear on reading the nonlimiting description which follows, referring to the appended drawings in which

• Figure 1 shows a product, handkerchief for example, with a peripheral connection area of the different folds. A corner has been delaminated to show the folds.
• Figure 2 shows an installation capable of allowing the production of a product according to the invention.
• Figure 3 shows a detail of the installation in Figure 2.

In Figure 1 there is shown schematically, and seen from above, a handkerchief or a napkin (1) square format consisting of 3 sheets (1a, 1b, 1c) of cellulose wadding bonded together, by gluing to the periphery, along an area (3) of determined width. According to the embodiment shown, the bonding was carried out by points (5) so as not to stiffen the complex; in accordance with the invention, the central area is not glued; it may, if necessary, include an embossing intended to improve the appearance thereof.

The peripheral zone (3) covers less than 50% of the total surface of the handkerchief or the towel, preferably this zone represents 30% to 40%.

For example, a napkin of dimension 40 cm x 40 cm will be bordered by a connecting strip formed by gluing the sheets from the edge line over a width of 4 cm. The linked area thus covers 36% of the total surface of the towel

According to a particularly preferred form of the invention, the connection effectively departs from the edge of the folds so as to avoid any yawning of the folds or else the formation of folds at the periphery which adversely affect the appearance of the product.

To make this type of product, any known installation can be used, for example the one shown in Figure 2. The folds (11) and (12), one being optionally double, of cellulose wadding coming from their respective reel, not shown, are guided to come around the rubber cylinders (13) and (14) then between them and embossing cylinders (15) and (16) in steel provided with appropriate reliefs. These reliefs can be distributed according to the pattern in Figure 1, for example. One of the folds (12) is glued by means of a rubber applicator cylinder (18) shown in FIG. 3. This cylinder comprises, in accordance with one embodiment of the invention, a part (181) in relief whose design corresponds to that of the peripheral area for gluing the sheets, so that the adhesive entrained by the applicator cylinder is distributed according to this pattern. According to this embodiment, one or both sheets can be embossed over their entire surface. Gluing is only carried out on the periphery corresponding to the part (181) of the gluing cylinder. According to another embodiment, one or both cylinders (15, 16) are provided with reliefs, along a peripheral zone of the desired product format. We can then use a smooth gluing cylinder.

After gluing, the folds (11) and (12) are assembled in the nip gap formed between the embossing rollers (15) and (16) which rotate at equal and opposite speeds. The multi-ply sheet from the device is drawn to a processing installation where it is cut and folded in accordance with the intended application: handkerchiefs, towels or the like.

According to a variant of the method, the plies (11) and (12) can come from the same coil with 2 plies, and have been subjected to a common calendering so as to effect a smoothing of the external face and confer greater sweetness. Then, only, the two sheets are separated to be embossed separately and individually.

According to another variant of the process, not shown, a fold, single or double, is embossed between a rubber cylinder and a suitably engraved steel cylinder, that is to say with reliefs according to the periphery of the desired product format. The adhesive is deposited on the tops of the reliefs. Finally one comes to apply on the fold a second respectively third fold, by means of a third rubber cylinder of matchmaker type. This third cylinder ensures both the embossing of the second respectively third fold and its marriage with the first. For the third cylinder, a steel or paper cylinder can also be used.

A test was carried out to test the behavior of the product on delamination compared to a control handkerchief.

A handkerchief was made by tying, using an adhesive in solution in water, PVA, 3 folds of format 21.5 x 21.5 cm, at the periphery on a strip of 2 cm wide.

15 mm wide test pieces were cut from the bonded area of the tissues and the 180 ° delamination test was carried out. This test consists in measuring the average delamination force of a test piece at a determined constant speed of 100 mm / min. For this, the ends of two folds are clamped between two pairs of jaws whose delamination force is to be measured, the two pairs of jaws are separated from one another, at constant speed, and the force exerted is measured. Its value is reduced to the unit of width. 180 ° delamination witness linked by simple embossing of the prior art sample with collage Average force (g / cm) / maximum force noted SM 0.55 / 1 2.4 / 6.4 ST 0.65 / 1 6.2 / 20

It can therefore be seen that bonding makes it possible to produce a product offering a greatly increased resistance to delamination, both in the forward direction (SM) and in the cross direction (ST).

Measurements carried out in addition, on a large number of samples of products existing on the market have shown that, whatever the embossing pattern produced either from spikes or from edge bars, it cannot be obtain a constant mechanical bond whose resistance to delamination reaches 1 g / cm in the forward or cross direction.

Examples: Product I

A handkerchief was made from 3 plies of cellulose wadding, consisting of 60% softwood fibers and 40% hardwood fibers, each having a basis weight of 18 g / m ² and incorporating an additive at a rate of 1.5 kg per tonne having a deliant effect on the free to improve smoothness (product marketed by the company ENKA NOBEL under the brand BEROCELL 595). The connection was made by peripheral bonding. Such a product would not be feasible with the prior art of peripheral embossing due to the presence of the additive.

Product II

We made a handkerchief with a central fold made from a mixture of softwood pulps (75%), hardwoods (10%) and a chemical-thermal pulp (grammage: 21 g / m ² ) incorporating an improving additive its resistance characteristics when it is in the wet state (product marketed by the company HERCULES under the brand KYMENE 557 H), and two cover plies made with a mixture of softwood pulp (65%) and hardwood (35% ) (grammage: 14.5 g / m ² ) incorporating an additive (BEROCELL 595) for softness. The connection was made by peripheral bonding.

Product III

• Liaison par gaufrage.

We made a control handkerchief from 3 plies (18 g / m ² ) without additives

• Embossing bond.

The measurement of the resistances, dry and wet and of the bursting, was carried out on specimens of 15 mm wide cut out in the zone of connection of the folds and is expressed in breaking length for each of the three products (cm) gathered in the table below: I II III Weight measured g / m ² 52.8 49.3 51.8 Thickness (mm) 0.20 0.21 0.18 Dry strength SM 505 630 580 ST 180 280 220 Elongation 10.5% 11% 12.5% Wet resistance SM 130 165 175 ST 52 95 65 Bursting Dry 330 440 450 Wet 100 170 115

Compared to control sample III, it can be seen that the invention allows the production of products having a wide range of characteristics depending on the application envisaged.

Claims (8)

1. Fibrous cellulosic product such as a handkerchief or serviette, produced by associating at least two individual plies, or sheets, of superimposed cellulose wadding, cut out to the required format and connected to each other along a peripheral area representing less than 50% of the total surface area of the product, characterised in that the said plies are bound by gluing along the said area so as to present a minimum resistance to delamination of 1 g/cm, the sum of the connection surfaces between the plies being less than the surface area covered by the said peripheral area.
2. Product according to Claim 1, characterised in that the gluing takes place over the whole circumference of the sheets.
3. Product according to one of the preceding claims, characterised in that the glue is deposited at points distributed discontinuously in the said area.
4. Product according to one of the preceding claims, characterised in that has embossing in the connection area.
5. Product according to one of the preceding claims, characterised in that the plies have different chemical and/or fibrous compositions.
6. Product according to Claim 5, characterised in that one of the plies comprises an additive which improves the mechanical characteristics of the sheet in the wet state.
7. Product according to Claim 5 or 6, characterised in that one of the plies comprises an additive which improves softness.
8. Product according to one of Claims 5 to 7, characterised in that the plies are produced using different pulps.

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