WO1999040809A1

WO1999040809A1 - Use of an air permeable paper sheet as support element for a layer of fabrics

Info

Publication number: WO1999040809A1
Application number: PCT/FR1999/000115
Authority: WO
Inventors: Christophe Guillaumot; Didier Bigot
Original assignee: Ahlstrom Lystil S.A.
Priority date: 1998-02-13
Filing date: 1999-01-20
Publication date: 1999-08-19
Also published as: CN1290136A; CN1124095C; AU2061199A; EP1052914A1; JP2002502923A; ES2172978T3; DE69901236T2; EP1052914B1; FR2774869A1; FR2774869B1; PT1052914E; DE69901236D1; CA2318384A1

Abstract

The invention concerns an air permeable paper sheet as support element for a layer of fabrics (mat) on a production line in particular during the cutting phase. The invention is characterised in that said sheet has in its thickness pores or fine perforations distributed over the whole surface thereof, said sheet having a bulkiness or hand more than 2.5 cm<3>/g, enabling it to allow air to pass through by the suction effect produced from beneath its lower surface.

Description

USE OF AN AIR PERMEABLE PAPER SHEET AS A SUPPORTING ELEMENT OF A STACK OF FABRICS

Technical area

The present invention relates to the technical sector of the clothing industry and relates more particularly to a new type of sheet support used as a conveyor / conveyor element of a mattress made up of a plurality of superposed textile layers and which is intended to be cut. in the form of elementary panels of suitable shape to be subsequently assembled together to produce the final product such as clothing.

Previous techniques

In the field of clothing, it has been proposed for a very long time, as is apparent in particular from FR-A-2 194 823 (corresponding to PUS

3,495,492) to produce mattresses from textile structures (fabrics, knits) intended to produce the made-up article, mattresses which are transferred to a cutting table.

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

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

Various solutions have been proposed for the pair-permeable supports which are used to support and transfer the mattress made of continuous textile sheets to the cutting station. 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, under the vacuum exerted below the stack, to exert a suction action tending to press the material against the support table.

Nowadays, the most used solution consists in having relatively rigid papers, perforated by stamping or scratching, below the stack, which have the essential advantage of being relatively low cost.

One of the problems which arise with such supports therefore comprising channels or orifices permitting the flow of air, resides in the fact that the suction is not distributed homogeneously over the entire surface of the mattress. and, in some cases, there can therefore be an irregular “densification” which can lead to defects in the cut panels.

In addition, the perforation is necessarily performed after the manufacture of the paper and therefore results in the production of waste.

Statement of the invention

The object of the invention is to propose using a paper sheet permeable to air as a support element for a stack of fabric on a clothing line, in particular as a support during the cutting phase. Such paper sheets are known per se 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 producing articles having a high absorption capacity of liquids with a view in particular to using them as wiping materials, hygiene articles, etc.

Now it has been found, and this is the subject of the invention, that it was possible to use such materials, inexpensive to manufacture, as support elements for a stack of fabrics (mattresses) on a clothing line, in particular during the cutting operation of said stack to produce elementary panels of appropriate shape and which are subsequently assembled together to produce the final product. It has been found, surprisingly, that the use of such a paper sheet, instead of relatively rigid papers, perforated by stamping or scratching which were used in this technical field, facilitated the compacting of the stack under the action of the suction exerted during this cutting phase, ensures good sliding during the positioning of said mattress on the table, avoids the marking of the textile structure, in particular when it is a structure light, and finally is practically usable for any type of textile structure.

For such an application, as a paper sheet intended to serve as a support, a sheet will be used which has in its thickness pores or fine perforations distributed over its entire surface, said sheet having a "volume" or "hand" expressed in cubic centimeters per gram, greater than 2.5, making it suitable for allowing the passage of air under the effect of a suction produced below 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 one 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 area with high air permeability 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 .

The invention also relates to a process for obtaining a paper sheet usable as a support element for a stack of fabric on a clothing line, which consists in producing a filter paper directly on a paper machine, without particular adaptation, characterized in that when obtaining said paper: - 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 dough 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, to a texturing treatment which consists in locally displacing the fibers by means of jets or blades of fluid through a canvas. coarse texture or of a perforated cylinder of the rotary printing cylinder type of screen printing type, so as to form patterns comprising a central region of high air permeability surrounded by an area of lower permeability.

In such a case of texturing treatment, the latter may have the consequence of either leaving only a small minority of fibers in the central part, or possibly achieving a real perforation free of fibers.

Such a treatment can be carried out on machines of known type, for 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 envisaged to incorporate synthetic or artificial fibers into the cellulosic pulp, and this at a rate of 5 to 25%, the incorporation of such fibers having an effect additional aerator of the sheet and, as a result of improvement in permeability.

It was found that an incorporation of less than 5% did not bring any significant influence and that if this contribution was more than 25%, on the one hand the manufacturing costs were appreciably increased and on the other hand and above all, 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, at a rate of the order of 5 to 25%, which makes it possible to produce a chemical bond improving the mechanical characteristics. It could possibly be envisaged to use less than 5% of additional binders, but then the mechanical characteristics are practically not improved. Above 25%, the costs are significantly increased without any noticeable improvement in the characteristics.

As reinforcing fibers, synthetic fibers such as polyester, polyamide, polypropylene, polyethylene, or even artificial fibers such as viscose or even natural fibers such as linen or cotton can be used.

The optional 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, etc. their polymers associated 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 by way of indication, but not limitation, examples in which the characteristics of the paper according to the invention are compared with three samples of paper. conventional perforations referenced respectively Echl, Ech2, Ech3.

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;

- Figure 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; - Figure 5 is, in turn, 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 a support element for a stack of fabrics on a clothing line from a conventional paper composition consisting of 77% unbleached Kraft pulp of the southern pine type, and 8% unbleached fluff pastry.

On the circuit, a sufficient supply of water is produced to obtain a final dilution of less than 1 g / liter, namely in the present case, 0.3 g / liter making it possible to ensure the homogeneity of the dispersion of the fibers. .

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

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

It has been found that when using, as a support element for a stack of fabrics on a clothing line, that such paper despite an average permeability of 309, while in the control samples, it can sometimes be significantly higher (see sample 2), that in practice, the plating of the stack of textiles on the cutting table was improved, cutting being facilitated.

This improvement can be explained on the one hand, 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 distributed regularly 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 a support for a stack of fabrics by proceeding, before addition of the binder as in Example 1, to a texturing treatment by passage over a conventional blade treatment machine or conventional fluid jets of the type sold by the company ICBT PERFOJET.

To make such a paper, a paper pulp is used comprising, as in Example 1:. 77% unbleached kraft pulp of the southern pine type and;

. 8% unbleached fluff dough.

The whole dough is defibrated / refined at only 15 degrees Schopper-Riegler at around 30 g / liter of water.

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

The fibrous web still wet thus formed receives a microperforation 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 a treatment makes it possible to locally obtain a partial or total displacement of the fibers according to the design of the cylinder or the mesh of the canvas. 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 on a composition comprising 5% pregelatinized cationic starch and 10% 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.

Compared to Example 1, a paper is obtained which has a significantly higher permeability than 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 incorporating reinforcing fibers into the paper pulp.

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

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

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

On the supply circuit on the forming fabric, a wet resistance agent consisting of 0.7% of polyamide epichlorohydrin resin is added.

The addition of water to the circuit is carried out in such a way that a final dilution is obtained of less than one gram / liter, making it possible to ensure the homogeneity of the dispersion of the fibers, which in this example is 0 , 3 g / liter.

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

After texturing treatment, a complementary bonding is carried out by depositing a composition of 5% pregelatinized cationic starch and 10% vinyl acetate latex.

The incorporation of these elements and binders is also carried out in a conventional manner 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.

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

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

. the distribution of pores in the structure being uniform, the risk of dust rising into 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 homogeneous 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 allows consider increasing the number of layers of fabric 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.

Of course, the invention is not limited to the embodiments described above, but it covers all the variants produced in the same spirit.

Claims

1 / Use of an air permeable paper sheet as a support element for a stack of fabrics (mattress) on a clothing line, in particular during the cutting phase, characterized in that said sheet has pores in its thickness or fine perforations distributed over its entire surface, said sheet having a "volume" or "hand" expressed in cubic centimeters per gram, greater than 2.5, making it suitable for allowing the passage of air under the effect of a suction produced below 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 less than a millimeter 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 comprising a central zone with high air permeability surrounded by a denser fibrous zone with more permeability low.

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 drying, by subjecting it to a texturing treatment which consists in locally displacing the fibers by means of jets or blades of fluid through a coarse-textured fabric or a perforated cylinder of the “rotary printing cylinder” type.

5 / Use of a sheet according to one of claims 3 and 4, characterized in that 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 being free of fibers and having a total surface area of the order of 1 to 2 mm 2.

6 / Use of a sheet according to one of claims 1 to 5 usable as a support element for a stack of fabrics on a clothing line, characterized in that it is obtained according to a process which consists: - to make a filter paper directly on a paper machine, without any particular adaptation, and this so that:

- 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 dough is brought to the machine at a very low concentration of less than one gram per liter, thus making 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.

Use of a sheet according to Claim 6, characterized in that synthetic, artificial or natural fibers are incorporated into the cellulosic pulp, thus making it possible to improve the tear resistance of the paper and having a complementary effect of leaf aerator, and as a result of improved permeability.

8 / Use of a sheet according to claim 7, characterized in that the synthetic or artificial fibers 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 one incorporates into said sheet, during its manufacture, an additional binder for performing a chemical bond improving the mechanical properties.