EP1052914B1 - Use of an air permeable paper sheet as support element for a layer of fabrics - Google Patents

Description

Technical area

The present invention relates to the technical sector of clothing and it has specifically relates to a new type of sheet media used as conveyor / conveyor element of a mattress consisting of a plurality of layers overlapping textiles and which is intended to be cut in the form of panels elementary of suitable shape to be later assembled together to make the final product such as clothing.

Previous techniques

In the field of clothing, it has been proposed for a very long time, as is clear in particular from FR-A-2 194 823 (corresponding to the US 3,495,492) to make mattresses from textile structures (fabrics, knits) intended to realize the made article, mattresses which are transferred on a table cutting.

During this operation, the fabric mattress is placed on a support breathable and the cutting into elementary panels is obtained by creating a depression below said table, so that the stack is maintained perfectly plated during the cutting phase.

To avoid any displacement of the elementary layers with respect to each other to others, and as is apparent in particular from the aforementioned FR and from FR-A-2,030,792 (corresponding to US 3,495,492), the mattress is covered at its upper part by a plastic film, airtight, which allows to densify said mattress during the cutting phase and avoids any displacement of the layers elementary with respect to each other.

Regarding the breathable supports that are used to support and transfer the mattress consisting of continuous textile sheets to the cutting station, various solutions have been proposed.

Thus, in FR 2 030 792, the support consists of a layer of material into which the tool can penetrate and which has channels or passages, which allows the vacuum exerted below the stack to exert an action suction tending to press the material against the support table.

Nowadays, the most used solution consists in having below stacking relatively rigid papers, punched by stamping or dogging, which have the essential advantage of being relatively inexpensive low.

One of the problems which arise with such supports therefore comprising channels or orifices allowing the flow of air, resides in the fact that the suction is not evenly distributed over the entire surface of the mattress and, in some cases, there may therefore be an irregular "densification" may cause defects in the cut panels.

In addition, the perforation must be carried out subsequent to the manufacture of paper and therefore leads to the production of waste.

Statement of the invention

The object of the invention is to propose using a paper sheet breathable as a support element for a stack of fabric on a line of clothing, especially as a support during the cutting phase. Such paper sheets are per se known as is apparent in particular from patents EP-A-616 074, EP-A-483 816 and EP-A-426 288 and have been proposed for carrying out articles having a great capacity of absorption of liquids in view in particular use them as wiping materials, hygiene articles ...

Now we have found, and this is the subject of the invention, that it was possible to use such materials, inexpensive to manufacture, as support elements of a stacking of fabrics (mattresses) on a clothing line, especially during the operation of cutting said stack to produce elementary panels of suitable shape and which are subsequently assembled together to achieve the final product.

It has been found, surprisingly, that the use of such a sheet paper mill, instead of relatively rigid papers, perforated by stamping or scratching which were used in this technical field, facilitated compaction of the stack under the action of the suction exerted during this cutting phase, ensures good glide when placing said mattress prevents the textile structure from being marked on the table, especially when it comes to of a light structure, and finally is practically usable for any type of textile structure.

For such an application, as a paper sheet intended to serve as support, we will use a sheet that has pores or fine in its thickness perforations distributed over its entire surface, said sheet having a "voluminosity" or "hand" expressed in cubic centimeters per gram, greater than 2.5, making it able to allow the passage of air under the effect of a suction produced below from its underside.

According to a first embodiment, the sheet structure has pores uniformly distributed over its entire surface, said pores having a diameter less than a millimeter and preferably between 50 and 150 microns.

According to a second embodiment, the pores or fine perforations are distributed in the form of patterns comprising a central zone with high permeability to air surrounded by a denser fibrous area with lower permeability.

Finally, according to a last embodiment, the pitch between the centers of two consecutive patterns is less than 5 mm and preferably less than 3 mm, the central zone with high permeability is free of fibers and has a total surface of the order from 1 to 2 mm ² .

• durant la préparation de la pâte, les fibres de cellulose (pâte de bois) sont individualisées sans trop les raffiner afin de conserver le maximum de perméabilité ;
• ladite pâte est amenée sur la machine à une concentration très faible inférieure à un gramme par litre, ce qui permet d'obtenir une feuille bouffante et ;
• la feuille produite n'est pas comprimée en partie humide de la machine afin de conserver sa perméabilité.

The paper sheet used as a support element on a clothing line can be obtained by a process which consists in producing a filter paper directly on a paper machine, without particular adaptation, the process having the following characteristics:

• during the preparation of the pulp, the cellulose fibers (wood pulp) are individualized without refining them too much in order to preserve the maximum permeability;
• said paste is brought to the machine at a very low concentration of less than one gram per liter, which makes it possible to obtain a puffy sheet and;
• the sheet produced is not compressed in the wet part of the machine in order to maintain its permeability.

Preferably, according to the invention, the permeability is maximized by subjecting the paper sheet produced, before drying, a texturing treatment which consists in locally displacing the fibers by means of jets or blades of fluid at the through coarse-textured canvas or a perforated cylinder like cylinder rotary screen printing type, so as to form patterns comprising a central area of high air permeability surrounded by an area lower permeability.

In such a texturing processing case, the latter may have consequence is to leave only a small amount left in the central part minority of fibers, or possibly achieve true free perforation fiber.

Such treatment can be carried out on machines of known type, by example of the type which is the subject in particular of FR-A-2 625 937.

Optionally, to improve the tear resistance of the paper, it can be considered incorporating synthetic fibers into the cellulose pulp or artificial, and at a rate of 5 to 25%, the incorporation of such fibers having elsewhere a complementary effect of aerator of the leaf and, as a result of improvement permeability.

It was found that an incorporation of less than 5% brought no significant influence and that if this contribution was greater than 25%, on the one hand significantly increased manufacturing costs and secondly and most importantly it is then essential to use additional binders.

Finally, in a known manner in the paper industry, it can be envisaged to incorporate an additional binder, in the range of 5 to 25%, which allows make a chemical bond improving the mechanical characteristics. He could possibly be considered to put less than 5% of additional binders, but then the mechanical characteristics are practically not improved. Above by 25%, the costs are significantly increased without significant improvement in characteristics.

As reinforcing fibers, synthetic fibers such as polyester, polyamide, polypropylene, polyethylene, even artificial than viscose or even natural fibers such as linen or cotton for example.

• polymères classiques également appelés « LATEX » en particulier de type acrylique, éthylène-vinyle-acétate, acétate de vinyle, alcool polyvinylique, styrène-butadiène,... et leurs polymères associés par co ou ter... polymérisation ;
• amidon, carboxy-méthyle-cellulose, hexa-méthyle-cellulose
• polyamide ou polyamine épichlorhydrine
• fibres thermoliantes.

The possible binders will be chosen from the following elements, possibly combined with one another:

• conventional polymers also called "LATEX", in particular of the acrylic, ethylene-vinyl-acetate, vinyl acetate, polyvinyl alcohol, styrene-butadiene, ... type and their associated polymers by co or ter ... polymerization;
• starch, carboxy-methyl-cellulose, hexa-methyl-cellulose
• polyamide or polyamine epichlorohydrin
• thermobonding fibers.

Way of realizing the invention

The invention and the advantages which it brings will however be better understood. thanks to the exemplary embodiments given below for information, but not limiting, examples in which the characteristics of the paper conforms to the invention are compared to three samples of conventional perforated paper referenced respectively Ech1, Ech2, Ech3.

• les figures 1, 2 et 3 sont des reproductions, à l'échelle 1, de trois papiers perforés conventionnels ;
• la figure 4 est une reproduction, avec un agrandissement de l'ordre de 200, d'une structure en feuille dans laquelle les pores sont répartis de manière uniforme sur toute la surface de ladite feuille et ;
• la figure 5 est, quant à elle, une reproduction agrandie de l'ordre de 30 d'une structure en feuille ayant reçu un traitement de textilisation assurant une réorientation des fibres.

These examples are illustrated by the appended figures in which:

• Figures 1, 2 and 3 are reproductions, on a scale of 1, of three conventional perforated papers;
• FIG. 4 is a reproduction, with an enlargement of the order of 200, of a sheet structure in which the pores are distributed uniformly over the entire surface of said sheet and;
• FIG. 5 is, for its part, an enlarged reproduction of the order of 30 of a sheet structure having received a texturing treatment ensuring a reorientation of the fibers.

Example 1

A paper is used which can be used in accordance with the invention as an element support of a stack of fabrics on a clothing line from a classic paper composition made of 77% unbleached Kraft pine-type pulp from the south, and 8% unbleached fluff dough.

On the circuit, there is a sufficient supply of water to obtain a dilution final less than 1 g / liter, namely in this case, 0.3 g / liter allowing to ensure the homogeneity of the dispersion of the fibers.

Binders consisting of 5% pregelatinized cationic starch are incorporated and 10% vinyl acetate latex, these binders being incorporated by any technique conventional such as padding, spraying or printing or "size-press" and in this case, a "size press".

After drying and crosslinking, the finished product is wound to the desired width by the user and has a structure as illustrated in FIG. 4.

The table below groups together the characteristics of such a product compared to three conventional perforated papers as illustrated in Figure 1 (Sample 1), Figure 2 (Sample 2) and Figure 3 (Sample 3). Characteristics Unit Invention "Perforated" papers Step 1 Ech 2 Ech 3 weight g / m2 45.6 67 84 56 Thickness microns 161 124 160 89 Hand cm3 / g 3.53 1.85 1.9 1.59 Permeability L / M2 / S under 196Pa 309 112 822 305 Machine direction break N / M 3252 3726 2898 1762 Cross direction rupture N / M 2123 1792 728 736 Machine direction elongation % 2.6 1.8 1.3 0.9 Crosswise elongation % 5.5 2.2 0.9 1.4 Machine direction tear Cn 187 198 185 100 Cross direction tear Cn 207 332 210 129 Average pore diameter microns 50 several millimeters

It has been found that during use, as a support element of a stack of fabrics on a clothing line, such a paper despite a average permeability of 309, while in the control samples it can sometimes be clearly superior (see sample 2), that in practice, the tackle the stacking of textiles on the cutting table was improved, the cutting being facilitated.

On the one hand, this improvement can be explained by the fact that the air produced by the suction source flows regularly over the entire surface of the paper through the pores which are evenly distributed over the latter, and that, moreover, this flow is also facilitated by the "hand", significantly higher compared to previous products.

Example 2

A paper sheet is produced which can be used in accordance with the invention as support of a stack of fabrics by proceeding, before addition of the binder as in Example 1, to a texturing treatment by passing over a machine conventional treatment by blades or conventional fluid jets of the type of those marketed by ICBT PERFOJET.

• 77 % de pâte kraft écrue de type pin du sud et ;
• 8 % de pâte fluff écrue.

To make such paper, use a paper pulp comprising, as in Example 1:

• 77% unbleached kraft pulp of the southern pine type and;
• 8% unbleached fluff dough.

All of the dough is fiberized / refined to just 15 degrees Schopper-Riegler about 30 g / liter of water.

As in Example 1, a sufficient supply of water is made on the circuit. to obtain a final dilution of less than 1 g / liter, in this case 0.3 g / liter, which ensures the homogeneity of the dispersion of the fibers.

The fibrous web still wet thus formed receives a micro-perforation treatment by blade or jet of fluid on a conventional installation of the type PERFOJET, with perforated cylinder or through an open structure fabric with a water pressure of 5 to 80 bars. Such treatment makes it possible to obtain locally a partial or total displacement of the fibers according to the design of the cylinder or the mesh of the Web. In the present case, the treatment is carried out with a blade of water at 9 bars.

After this operation, binders are added by any appropriate means, padding, spraying, printing or "size press", these binders being based of a composition comprising 5% of pregelatinized cationic starch and 10% of vinyl acetate latex.

After drying and crosslinking, the finished product is wound to the desired width for the intended use having a structure as illustrated in FIG. 5.

The table below groups together the characteristics of such a product compared to three conventional perforated papers. Characteristics Unit Invention "Perforated" papers Step 1 Ech 2 Ech 3 weight g / m2 35.6 67 84 56 Thickness microns 163 124 160 89 Hand cm3 / g 4.59 1.85 1.9 1.59 Permeability L / M2 / S under 196Pa 1081 112 822 305 Machine direction break N / M 1707 3726 2898 1762 Cross direction rupture N / M 1152 1792 728 736 Machine direction elongation % 2.5 1.8 1.3 0.9 Crosswise elongation % 6.1 2.2 0.9 1.4 Machine direction tear Cn 146 198 185 100 Cross direction tear Cn 169 332 210 129 Average pore diameter microns 150 several millimeters

Compared to Example 1, a paper is obtained which has a permeability significantly superior to previous papers and which, compared to the product produced according to example 1, makes it even more suitable as a support for a stack of fabrics on a clothing line.

Example 3

Example 2 is repeated except that incorporated into the pulp pulp reinforcing fibers.

The aqueous composition comprises 72% of unbleached kraft pulp of the pine type south and 9% unbleached fluff dough.

The whole dough is fiberized / refined at only 18 degrees Schopper-Riegler and we incorporate 5% polyester fibers, 1.7 decitex - cut 18 mm.

The mixing in water is carried out at a rate of approximately 15 to 20 g / liter.

On the supply circuit on the training canvas, we add a wet strength consisting of 0.7% polyamide epichlorohydrin resin.

The addition of water to the circuit is carried out in such a way that a final dilution of less than one gram / liter, ensuring homogeneity of the dispersion of the fibers which, in this example, is 0.3 g / liter.

The wet fibrous web thus formed is similarly textured in Example 2, the fluid pressure being 11 bars and the water layer having been replaced by fluid jets, at a rate of approximately 100 jets / needles per meter of width to obtain a structure similar to that of Example 2 and which spring of figure 5.

After texturing treatment, a complementary bond is made by deposition of a composition of 5% pregelatinized cationic starch and 10% of vinyl acetate latex.

The incorporation of these elements and binders is also carried out with a conventional way and, after drying / crosslinking, the finished product is also wound to the desired width.

The table below groups together the characteristics of such paper compared to conventional perforated papers. Characteristics Unit Invention "Perforated" papers Step 1 Ech 2 Ech 3 weight g / m2 37.4 67 84 56 Thickness microns 160 124 160 89 Hand cm3 / g 4.28 1.85 1.9 1.59 Permeability L / M2 / S under 196Pa 644 112 822 305 Machine direction break N / M 2905 3726 2898 1762 Cross direction rupture N / M 1646 1792 728 736 Machine direction elongation % 2.1 1.8 1.3 0.9 Crosswise elongation % 6.0 2.2 0.9 1.4 Machine direction tear Cn 168 198 185 100 Cross direction tear Cn 240 332 210 129 Average pore diameter microns 100 several millimeters

Such paper is also perfectly suited to serve as a support element. of a stack of fabrics on a clothing line.

• la répartition des pores que comporte la structure étant uniforme, le risque de remontée de poussières dans le textile lors de l'opération de coupe est quasiment nul ;
• de plus, l'uniformité de la feuille assure une meilleure glisse sur la surface de découpe sans encrassement de cette dernière ;
• une telle feuille étant parfaitement plane, cela élimine pratiquement tous risques de marquage à la surface des textiles, en particulier dans le cas de textiles fins ;
• de par son uniformité, une telle feuille assure une épaisseur plus homogène du matelas, assurant par là même une meilleure découpe du textile ;
• l'uniformité de la feuille assure également une épaisseur globalement moindre du fait de l'absence de bosses et de creux, ce qui permet d'envisager d'augmenter le nombre de couches de textile dans le matelas et ;
• enfin et surtout, il est possible d'utiliser un tel support quel que soit le type d'étoffe entrant dans l'empilement, alors que, antérieurement, il convenait d'utiliser des gammes de papier perforé ayant des caractéristiques différentes.

Compared to previous perforated papers used as supports for stacking fabrics on a clothing line, the proposed paper sheet has very many advantages, among which we can cite:

• the distribution of pores in the structure being uniform, the risk of dust rising in the textile during the cutting operation is almost zero;
• moreover, the uniformity of the sheet ensures better sliding on the cutting surface without fouling of the latter;
• such a sheet being perfectly flat, this eliminates practically all risks of marking on the surface of textiles, in particular in the case of fine textiles;
• due to its uniformity, such a sheet ensures a more uniform thickness of the mattress, thereby ensuring better cutting of the textile;
• the uniformity of the sheet also ensures a generally reduced thickness due to the absence of bumps and hollows, which makes it possible to envisage increasing the number of layers of textile in the mattress and;
• finally and above all, it is possible to use such a support whatever the type of fabric entering the stack, whereas, previously, it was appropriate to use ranges of perforated paper having different characteristics.

Claims (9)

1. Use of an air-permeable paper sheet as support element for a stack of fabrics on a manufacturing line, especially during the cutting phase, characterized in that said sheet has, in its thickness, pores or fine perforations distributed over its entire surface, said sheet having a "bulk" or "body" expressed in cubic centimetres per gram of greater than 2.5, making it capable of allowing air to pass through it due to the effect of suction produced beneath its underside.
2. Use of a sheet according to Claim 1, characterized in that said sheet has pores uniformly distributed over its entire surface, said pores having a diameter of less than one millimetre and preferably between 50 and 150 microns.
3. Use of a sheet according to Claim 1, characterized in that the pores or fine perforations of said sheet are distributed in the form of patterns having a central region with high air permeability surrounded by a denser fibrous region with lower permeability.
4. Use of a sheet according to Claim 3, characterized in that the pores or fine perforations distributed in the form of patterns are produced during the production of the paper sheet, before it is dried, by subjecting it to a textiling treatment which consists in locally displacing the fibres by means of fluid jets or knives through a mesh having a coarse texture or through a perforated cylinder of the "rotary printing cylinder" type.
5. Use of a sheet according to either of Claims 3 and 4, characterized in that the spacing between the centres of two consecutive patterns is less than 5 mm and preferably less than 3 mm, the central region with high permeability containing no fibres and having a total area of about 1 to 2 mm².
6. Use of a sheet according to one of Claims 1 to 5, characterized in that the sheet is obtained according to a process which consists in producing a filter paper directly on a paper machine, without any special modification, and in such a way that:

   during the preparation of the pulp, the cellulose fibres (wood pulp) are individualized without refining them excessively so as to maintain the maximum permeability ;

   said pulp is fed to the machine with a very low concentration of less than one gram per litre, thus making it possible to obtain a bulking sheet; and

   the sheet produced is not compressed at the wet end of the machine so as to maintain its permeability.
7. Use of a sheet according to Claim 6, characterized in that synthetic, artificial or natural fibres are incorporated into the cellulose pulp, thus making it possible to improve the tear strength of the paper and having a complementary effect of aerating the sheet, and consequently of improving the permeability.
8. Use of a sheet according to Claim 7, characterized in that the synthetic or artificial fibres are incorporated in an amount of 5 to 25%.
9. Use of a sheet according to one of Claims 6 to 8, characterized in that an additional binder is incorporated into the said sheet during its manufacture, making it possible to achieve chemical bonding, which improves the mechanical properties.

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