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Title:
METHOD FOR FINISHING A SHEET MATERIAL
Document Type and Number:
WIPO Patent Application WO/2012/127260
Kind Code:
A1
Abstract:
A method for finishing a sheet material (1) comprising the steps of : — obtaining intaglio and/or relief decorative motifs (3) on a temporary laminar support (2); — distributing on a first side (4) of said temporary laminar support (2) a product (18, 19) that is the precursor of said sheet material (1); — applying on said product (18, 19) a pressure such as to imprint thereupon said intaglio and/or relief decorative motifs (3), wherein said obtaining comprises modifying the thickness (T) of said temporary laminar support (2) by acting on a second side (10) of said support (2), opposite said first side (4), such as to define differentiated compliance zones (Z) that during the application of said pressure generate corresponding intaglio and/or relief decorative motifs (3) to said first side (4).

Inventors:
BORSANI ADELMO (IT)
Application Number:
PCT/IB2011/000618
Publication Date:
September 27, 2012
Filing Date:
March 22, 2011
Export Citation:
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Assignee:
ANCAPLAST S N C DI CARLO BORSANI & C (IT)
BORSANI ADELMO (IT)
International Classes:
D21H27/00; B29C37/00; B29C39/14; B29C59/02; B29C59/04; D06N3/00
Foreign References:
JPS63270879A1988-11-08
US20070116929A12007-05-24
Other References:
None
Attorney, Agent or Firm:
CRUGNOLA, Pietro et al. (Viale Corassori 54, Modena, IT)
Download PDF:
Claims:
CLAIMS

Method for finishing a sheet material (1) comprising the steps of:

— obtaining intaglio and/or relief decorative motifs (3) on a temporary laminar support (2) ;

— distributing on a first side (4) of said temporary laminar support (2) a product (18, 19) that is the precursor of said sheet material (1) ;

— applying on said product (18, 19) a pressure such as to imprint thereupon said intaglio and/or relief decorative motifs (3),

characterised in that said obtaining comprises modifying the thickness (T) of said temporary laminar support (2) by acting on a second side (10) of said support (2) , opposite said first side (4) , so as to define zones (Z) of differentiated compliance that during the application of said pressure generate corresponding intaglio and/or relief decorative motifs (3) on said first side (4) .

Method according to claim 1, wherein said obtaining comprises locally removing portions of said temporary laminar support (2) such as to define said zones (Z) of differentiated compliance.

Method according to claim 1 or 2 , wherein said obtaining comprises grinding said temporary laminar support (2) by acting on said second side (10) .

Method according to claim 3, wherein said grinding is performed by a grinding belt element (8) , or by a grinding roller element (11) or by a nozzle (12) dispensing a jet (13) of grinding sand.

Method according to claim 3 or 4 , wherein said support (2) partially winds a moving cylinder (6) from which it is advanced and near which said grinding occurs, said support (2) being in contact with an abutting surface (16) of said cylinder (6) on which incisions (17) and/or relief parts are obtained. Method according to any one of claims 1 to 5 wherein before said distributing a film (7) of antiadhesive material is applied to said first side (4) in such a manner as to enable said temporary laminar support (2) of said sheet material (1) to be removed once it has been obtained.

Method according to claim 6, wherein said film (7) is made of silicone and/or of polyolefin.

Method according to any preceding claim, wherein after said exerting said product (18, 19) is subjected to a cross- linking and shape-stabilisation treatment so as to define a finishing layer (19) .

Method according to any preceding claim, further comprising gluing onto said product (18) a supporting element (20) chosen from a group comprising: a fabric, a coagulated base, a non-woven fabric, a microfibre support .

Method according to claim 9 as appended to claim 8, wherein said gluing comprises gluing said supporting element (20) on said finishing layer (19) such as to generate said sheet material (1) .

Method according to claim 8, or according to claim 9 or 10 as appended to claim 7, wherein after said cross- linking and shape-stabilisation treatment said sheet material (1) is removed from said temporary laminar support (2) to obtain said finished sheet material (1) . Method according to any one of claims 1 to 11, wherein said temporary laminar support (2) comprises a support made of "carte release" .

Method according to any one of claims 1 to 12, wherein said product (18) comprises polyamide and/or polyurethane and/or polyvinyl chloride, and/or phenol and/or melamine resins .

Method for preparing a temporary laminar support (2) intended for finishing a sheet material (1) , comprising — obtaining intaglio and/or relief decorative motifs (3) on said temporary laminar support (2) ;

— treating a surface side (10) of said temporary laminar support (2) , opposite a further side (4) having an antiadhesive surface and being intended for coupling with a product (18, 19) that is the precursor of said sheet material (1), said treating comprising modifying locally the thickness (T) of said support (2) by acting on said side (10) so as to define differentiated compliance zones (Z) that through the effect of a pressure applied to said product (18, 19) generate corresponding intaglio and/or relief decorative motifs (3) on said further side (4) .

Method according to claim 14, wherein said treating comprises grinding said laminar support (2) by acting on said side (10) , and wherein said temporary laminar support (2) comprises a support made of "carte release".

Description:
Method for finishing a sheet material

The invention relates to a method for finishing a sheet or laminar material, which is usable in various fields such as the clothing, furnishing, footwear fields, the leather accessories field, the field of upholstery for car or boat seats or other parts and further fields.

The method according to the invention is in particular usable to obtain imitation leather and more in general products consisting of textile supports to which synthetic resins are applied, these textile supports comprising, for example, fabrics, coagulated bases, non-woven fabrics, microfibres, etc .

In the prior-art a method is known for obtaining an imitation- leather sheet material that uses a temporary support of so-called "carte release" . The "carte release" is a paper support, i.e. a cellulose-based support, to a surface of which a film of plastics is applied that generates an antiadhesive surface. A film of silicone is often used to generate this antiadhesive surface. The antiadhesive surface confers on the "carte release" a capacity to detach itself and not stick to further substances in such a manner that the "carte release" can act as a temporary support for the latter, as will be specified below.

The "carte release", provided with the antiadhesive film of plastics, is subjected to an embossing process, i.e. it is made to interact with a pair of embossing elements, one of which comprises relief motifs, and the other may comprise corresponding intaglio motifs that define a desired drawing or decoration. The pair of embossing elements comprises a pair of calendaring rollers. The two rollers interact, exerting a certain pressure against one another and the relief motifs couple with corresponding intaglio motifs, whilst the "carte release" remains interposed therebetween. Once the embossing process has been concluded, the "carte release" has local reliefs and incisions, i.e. decorative impressions or motifs, which, as will be seen below, are impressed on a product to give the product the desired pattern, veins or surface features that are typical of a tanned animal hide or also of surfaces with fancy patterns. Once embossing has been performed, on the antiadhesive surface of the "carte release" a layer of plastics materials in paste form of the desired colour is spread such as polyurethane, polyamide, or polyvinyl chloride, on which the impressions or decorative motifs remain impressed that were previously obtained on the carte release. The layer of plastics material, which is also known as a facing or finishing layer, is subjected to heat treatment so as to undergo a cross -linking and stabilisation reaction that transforms the plastics from a pasty state into a layer with elasticity. The aforesaid layer of plastics material is the precursor of the finishing layer of the imitation leather product that it is desired to obtain.

To the aforesaid layer of plastics material other layers of plastics material are subsequently added and then a textile support is coupled and glued, i.e. a fabric, or a coagulated base, a non-woven fabric or a microfibre support. Lastly, the textile support and the finishing layer, which are both inseparably coupled in such a manner as to form a single element, are detached and separated definitively from the "carte release" , which has until now acted as a temporary support .

On the surface of the layer of finishing plastics material that was previously in contact with the "carte release" the desired impressions or decorative motifs impressed by the "carte release" remain visible. In other words, the pattern embossed negatively on the "carte release" remains impressed positively on the finished product.

A drawback of the known method disclosed above is that it is certainly not cheap and is moreover rather complex to perform. Further, the known method involves the use of very costly means, that are structurally complex and require constant maintenance in order to maintain an acceptable level of productive quality.

In particular, to obtain acceptable levels of quality in the finishing of the finished product, it is necessary to operate with the greatest possible precision to impress the decorative motifs on the "carte release" . This means that the embossing elements necessarily have to be perfectly positioned in relation to one another, i.e. be synchronised together in order to make the relief motifs on the one hand and the intaglio motifs on the other hand coincide perfectly, especially in the case of drawings with very distanced contours in which the definition or clarity on the pattern to be obtained is often lost.

It is clear that even minimal wear, or the undesired interposing of even miniscule bodies between the embossing elements irreparably damages the quality of the obtained product, causing great financial loss.

An object of the invention is to improve the methods for finishing a sheet or laminar material.

A further object of the invention is to provide a method for finishing a material that is simultaneously cheap, fast, effective and simple to implement.

According to the invention, a method is provided for finishing a sheet material as defined in claim as defined in claim 1.

The invention can be better understood and implemented with reference to the attached drawings, which show an embodiment thereof by way of non- limiting example, in which:

Figure 1 shows schematically a step of the method according to the invention according to a first possible operating method;

Figure 2 shows schematically the step of the method in Figure 1 but performed according to a second possible operating method; Figure 3 shows schematically the step of the method in Figure 1 but performed according to a third possible operating method;

Figure 4 is another view which is similar to that in Figure 1;

Figure 5 is an enlarged detail of Figure 4;

Figure 6 shows a detail of Figure 5 ;

Figures 7a to 7f show a temporary support and a sheet material in different steps of the method according to the invention.

With reference to Figures 1 to 7, a method for finishing a sheet or laminar or web- shaped material 1 is shown. Once the sheet material 1 is finished it is usable in various sectors such as the clothing, furnishing and footwear sectors. Further, the material 1 can be used to cover leather accessories, or for the upholstery of seats or other parts of cars or for furnishing complements.

The method according to the invention is suitable for obtaining imitation leather or more in general products consisting of fabric supports to which synthetic resins are applied, such textile supports comprising, for example, fabrics, coagulated bases, non-woven fabrics, microfibres, etc ..

In a first step on a temporary laminar support 2, in particular a "carte release" support, intaglio and/or raised decorative motifs 3 are obtained, that can reproduce various veins, shades or in general surface features of various types of hide or leather or any desired pattern that is also suitable for technical fabrics.

"Carte release" is a material having a cellulose-based support layer 5 to which, on a sole side 4 of which a patina or film of plastics 7, for example of silicone and/or of polyolefin, or also several films are applied, that modify the surface properties thereof, giving a detaching and antiadhesive effect thereto that is important for what will be described below. The film of plastics o patina 7 thus defines an antiadhesive surface the function of which will be disclosed below.

The method according to the invention modifies the thickness T of the temporary laminar support 2 by acting on a second side 10 of the latter, opposite the first side 4, i.e. by treating the face of the support 2 opposite the one in which the antiadhesive surface defined by the film of plastics 7 is provided. The thickness is modified, as detailed below, by removing parts 14 of the layer 5 of the support 2, so as to define zones Z of differentiated compliance, i.e. of the zones that, having locally a thickness that is less than further surrounding zones, are subject to yielding more, i.e. to undergoing a movement in the direction of the thickness under the effect of stress or pressure, as disclosed below. These parts 14 of the layer 5 can be removed by a grinding operation. The grinding operation entails detaching from the layer 5 parts or portions 14 of very reduced dimensions, for example portions in the shape of granules 14, or in the form of down or filaments or fibres.

Grinding can be performed using various modalities. In a first modality, shown in Figures 1, 4, 5, there is provided advancing the support 2, which is wound and moved by a suitable cylinder 6, along a first advance direction A. The "carte release" support 2 is oriented in such a manner as to enable the second side 10 to be machined. In other words, it is the back of the "carte release" that is exposed for machining, or, equivalently, it is the face devoid of the film of plastics 7 defining the antiadhesive surface that is processed in this step.

A grinding belt 8 is provided that is suitable for being advanced in such a manner as to interact in contact with the "carte release" support 2. The grinding belt 8 is wound around a transmission roller 9 that rotates in a rotating direction opposite that of the cylinder 6. The grinding belt 8 has an irregular surface on which abrasive grains are fixed. In other words, the surface of the grinding belt 8 is rough as it has to be abrasive. The transmission roller 9 comprises a substantially smooth and regular contact surface 15, in such a manner as to receive the grinding belt 8 perfectly restingly and push the grinding belt 8 against the "carta release" in a grinding operating zone S.

The cylinder 6 can be provided externally with an abutting surface 16 provided with suitable incisions 17 and/or relief parts. The incisions 17 are shaped according to desired drawings or motifs. The cylinder 6 and the transmission roller 9 can be adjusted in such a manner as to be pushed against one another in a suitable manner according to the intensity required in the grinding operation. The support 2 is maintained at a suitable tension. The grains of the grinding belt 8, coming into contact with the support 2, acting at a certain pressure on the latter and cooperating with incisions 17 and/or with relief parts of the abutting surface 16 perform the grinding action effectively, defining on the support 4 the zones Z of differentiated compliance that are located and distributed according to the desired methods. The zones Z can have geometrical shapes that depend on the configuration of the abutting surface 16, in particular on the conformation of the incisions 17 and/or relief parts.

Unlike what occurs in the prior-art in which it is necessary, with great difficulty and expenditure of time and money, to synchronise perfectly together the embossing rollers or the two embossing press rollers, with the method according to the invention, all this is avoided, owing to the fact that the grinding means used, for example the grinding belt 8 or grinding roller 11, does not need to have the position phased or adjusted or synchronised. The grinding action aimed at obtaining the decorative motifs 3 is obtained whatever the portion of the grinding belt 8 or grinding roller 11 that interacts with a determined zone of the cylinder 6. The advancing position of the grinding belt or roller with respect to the "carte release" is not univocal and does not require expensive and long adjusting operations.

By using the method of the invention, advantageously the surface of the "carte release" does not undergo any compression stress, as on the other hand occurs in the prior- art, and thus enables the "release" effect to last a long time, i.e. the detachment capability, thus enabling the "carte release" to be reused a large number of times. This leads to clear advantageous effects from the financial point of view. Further, the surface of the "carte release" maintains the initial finish, maintaining the original opaque appearance thereof that may be important for "car- interior" applications, in particular for so-called "total matt" applications.

The grinding belt 8 in contact with the second side 10 of the support 2 made of "carte release" removes small parts 14 thereof, generating a series of engraved decorative motifs 3, the shape of which may depend on the configuration of the abutting surface 16, such engraved decorative motifs 3, as will be described further on, surprisingly being able to reproduce various decorative surface shapes, for example the veins or motifs that are typical of hide or any other pattern which in turn may not be made with the prior art method for a series of applicational reasons. In particular, grinding of the second side 10, and thus the removal of parts 14 of the supporting layer 5, locally modifies the thickness T of the latter such as to define the aforesaid zones Z having differentiated compliance.

For the grinding operation according to the method that has just been disclosed i.e. using the grinding belt 8, tests have been conducted successfully using grinding machines provided by the company ALETTI GIOVANNI & FIGLI S.R.L. of Varese (Italy) .

Figure 2 shows an alternative modality with which to perform the aforesaid grinding operation, in which, instead of a grinding belt 8, a grinding roller 11 is used, with results that are substantially similar to those that have just been seen .

Figure 3 shows a further alternative modality with which to perform the aforesaid grinding operation, in which a nozzle 12 is used to dispense a jet 13 of grinding sand or the like. A template or mask element can also be provided that is interposable between the nozzle 12 and the support 2, near the latter to shield zones of the second side 10 and let the jet 13 act on other zones that have been left selectively uncovered to grind second determined motifs or patterns. In this case the support 2 can also be advanced in an intermittent manner, i.e. by steps, the jet 13 being activated at each step.

At the end of the grinding operation the temporary laminar support 2, as shown in Figures 6 and 7a, is ready to perform a subsequent step.

With reference to Figures 7b and 7c, on the first side 4 of the temporary laminar support 2, in this case the "carte release" , a product 18 made of plastics material is distributed, such as polyurethane , and/or polyamide, and/or polyvinyl chloride, intended to generate a finishing plastics layer 19. The product 18 acts as a precursor element of the sheet material 1 that will be obtained. The product 18 may have a desired colour or may have several colours. In particular, the product 18 may contain a colouring substance or several substances that generate a mixture of colours . The product 18 can be applied by spraying in one ore more steps, or can be spread by a doctor-blade device, or can be applied according to other equivalent methods .

On the finishing plastics layer 19 a certain pressure is exerted in such a manner that the impressions or decorative motifs 3 previously obtained on the "carte release" 2 remain impressed thereupon. The "carte release" 2, under the pressing action, owing to the zones Z, behaves exhibiting differentiated compliance, i.e. with a degree of compliance that varies from zone to zone according to the motifs 3 that were made on the second side 10 of the "carte release" 2. The layer 19 is further subjected to high-temperature treatment so as to undergo a cross-linking and stabilisation reaction that gives the layer 19 a certain elasticity. At this point, a definitive supporting element 20 is applied, in particular glued, that may be made of microfibre, or a fabric, a non-woven fabric, a coagulated base or other suitable materials. The definitive supporting element 20 acts as a structural supporting element for the finishing layer 19 thus conferring mechanical resistance.

Once the element 20 and the layer 19 are solidly coupled, giving rise to the sheet material 1, the latter can be removed from the temporary laminar support 2, as shown in Figure 7f.

On the layer 19 that was before in contact with the "carte release" 2 the impressions and the decorative motifs impressed by the "carte release" 2 are impressed. In other words, the drawings or motifs engraved negatively on the "carte release" 2 remain impressed positively on the layer 19.

The support 2, i.e. the carte release can be used several times to obtain sheet material 1.

Advantageously, it is also possible to use an already embossed "carte release" on which also the grinding step is conducted according to the method of the invention. In this manner, to a first pattern already defined by the embossing, a second pattern is added that is made by grinding and which may be complementary to the first pattern, such that the final result gives rise to a design that is difficult to obtain with prior-art techniques.

The sheet material 1 is at this point ready for being used for the various applications that were mentioned previously such as: clothing, furnishings - for example for finishing laminates and/or profiled section bars - the sector of footwear and leather accessories such as belts, bags and suitcases, and also technical, industrial, medical and yet other applications.

The material 1 obtained has great aesthetic appeal in addition to great mechanical properties and other qualities such as impermeability to water in liquid state but not to water vapour. Further, the material 1 is easy to clean and to machine, in particular to sew and is also easy to manage and process owing to the fact that it can be easily stored in rolls .