EP1348799A1 - Method for producing an expanded and coated textile - Google Patents

Abstract

Coated, expanded textile materials are produced by applying a coating material to one side of a textile support, crosslinking this material, applying a rubber material to the other side and then crosslinking and expanding the rubber. A method for the production of coated, expanded textile material involves using a double-sided textile support (possibly with a printed pattern on side 2), applying a coating material (I) to side 2, crosslinking (I), applying a rubbery material (II) to side 1, crosslinking and expanding (II) (successively or simultaneously) and possibly applying a protective treatment to the coated surface.

Description

The present invention relates to a process for preparing textiles expanded and coated.

Printed coated fabrics currently available, for example for the production of tablecloths or other articles in the field of tableware, generally have a coating layer based on PVC (polychloride vinyl) and / or halogenated polymers, in particular fluoropolymers which are detrimental in terms of recyclability. What's more, these fabrics resist poorly with food stains which remain more and more marked over the time and become increasingly difficult to remove. At the same time, they may lose their colors or print patterns, especially as and as cleaning or under the effect of light, or even give rise yellowing.

One of the objectives of the present invention is precisely to propose a process for manufacturing a coated textile, usable in particular in the field of tableware, and not having the drawbacks mentioned above, that is to say which is anti-stain and not subject to yellowing.
Another objective of the invention is to provide a coated textile combining the aforementioned qualities, non-slip, anti-shock and anti-heat functions. This second objective is for its part satisfied by the application on the back of the coated face of the printed textile, an expanded rubbery material.

The difficulty encountered and overcome according to the present invention carries precisely on the calendering of a rubbery material on the back of a textile with the front side already coated.

By definition, calendering refers to a technique for manufacturing sheets, plates or films comprising laminating a material thermoplastic between several cylinders constituting the grille. Generally in the rubber industry, this calendering operation is associated with a coating of the rubbery material on the surface of a porous support, for example a fabric. Following this operation of calendering, the rubbery material is subjected to an operation of vulcanization or crosslinking during which the chemical transformation of the starting elastomeric mixture into a network reticle. In the particular case of the preparation of so-called rubbery articles expanded, at least one blowing agent is incorporated into the starting mixture. By decomposing under the action of heat, this agent generates gases, which gases develop bubbles in the elastomeric medium of low viscosity. This results in the expected expanded cell structure.

In the case of the present invention, the waterproof nature of the coating turns out incompatible with subsequent calendering of a layer of elastomer (s) on the opposite side. The sealing of the coating constitutes an obstacle to the release expansion gases.

Unexpectedly, the inventors discovered that it was possible to overcome this difficulty.

• on dispose d'un textile formant support comportant une première face et une deuxième face et présentant le cas échéant des motifs imprimés sur sa deuxième face,
• on dépose sur la deuxième face du support textile un matériau d'enduction,
• on procède à la réticulation du matériau d'enduction,
• on dépose sur la première face du support textile un matériau caoutchouteux,
• on procède successivement ou simultanément à la réticulation et l'expansion du matériau caoutchouteux,
• on réalise éventuellement un traitement de protection de la face enduite du textile.

More specifically, the invention provides a process for the preparation of the coated textile printed above, characterized in that:

• there is a textile forming a support comprising a first face and a second face and, where appropriate, having patterns printed on its second face,
• a coating material is deposited on the second face of the textile support,
• the crosslinking of the coating material is carried out,
• a rubbery material is deposited on the first face of the textile support,
• the crosslinking and the expansion of the rubbery material are carried out successively or simultaneously,
• a protective treatment of the coated face of the textile is optionally carried out.

The deposits of the materials which must respectively constitute the coating and the expanded on either side of the textile support are generally produced by calendering or coating.
Following this calendering step, each material is then subjected to at least one crosslinking operation in order to transform the starting elastomeric mixture into a crosslinked network.
In the case of the rubbery material, this crosslinking operation is combined with an expansion operation.

In general, the methods for manufacturing conventional expanded rubber materials integrate the two crosslinking and expansion operations concomitantly. Conventionally, the elastomeric strip or ply is recovered at the end of the calendering operation to then be placed in an enclosure heated to the appropriate temperature for the execution of the crosslinking operation.
According to a preferred variant of the invention, the crosslinking and expansion stages are carried out simultaneously, at short notice and in continuity with the calendering operation, this makes it possible to optimize the mechanical qualities mainly in terms of elasticity, expanded rubbery cellular material thus obtained.
More preferably, these two crosslinking and expansion stages are carried out continuously by horizontal displacement of the material which has just been calendered, in an enclosure, preferably a tunnel brought to the appropriate temperature for the concomitant execution of the crosslinking and of expansion, not in an oven and on a vertical plane in accordance with conventional methods.

Cross-linking and expansion reactions are generally performed at atmospheric pressure.

In a variant of the invention, the rubber mixture expandable may, following the calendering operation and beforehand during the crosslinking and expansion operation, undergo a graining operation.

This operation aims to apply on the exposed face of the calendered rubbery cellular material unevenness forming protrusions and hollows whose all surfaces have a certain grain and are more or less regular and not smooth. The appearance of the product is considerably improved.
In this particular case, after calendering the rubbery material, there is printed in relief, on the exposed face of the layer obtained by calendering, that is to say not linked to the textile support, any pattern which will be preserved at the level of the 'finished article.

The supporting fabric may comprise or consist of a fabric, a nonwoven or a mesh, the fabric and the nonwoven being preferred. It can be either natural, artificial or synthetic textile. It may be an unbleached or white textile, a dyed woven textile, a mass-dyed textile, a dyed woven textile or a printed textile. According to a preferred variant of the invention, this textile support is dyed or has a printed face.
The choice of the texture of the textile support is generally made so that with a coating of the order of 25 g / m2 the air permeability of the support in a coated form is sufficient to be compatible with the production of calendering, crosslinking and expansion of the rubbery material on its back.
In this case, the textile support generally has a texture of 24 × 24 threads per cm for a title of 34 × 34 metric numbers. However, it is possible to also use a textile support having a warp texture of 24 to 40 threads per cm, or 28 to 50 metric numbers and / or a weft of 16 to 30 threads per cm, or 28 to 50 metric numbers .

The composition of the coating layer is preferably compatible with an application on a textile support, either by calendering or extrusion, or by loom to be coated with a tunnel.
Preferably, the first coating layer is applied at a rate of approximately 10 to 25 g / m ² on the surface of the first face of the second layer.

The coatings derived from at least one acrylic resin, of polyurethane or one of their mixtures prove to be particularly advantageous in the context of the present invention.
This coating layer may also contain various additives, in particular to improve and / or modify the mechanical properties of the final printed coated textile, its UV resistance. It may in particular be plasticizer (s), screw protection agent (s). -to UV ...
According to a preferred variant of the invention, the weight ratio coating layer / textile support is between 5 and 15 and preferably 7 and 12.

As appears from the definition of the claimed textile support, it is imperative that the thickness of this coating layer and / or the texture of the textile support are adjusted to obtain the permeability required according to the invention.
In this case, too much crossing of the coating layer causes a sealing of the textile support and causing poor expansion of the layer of rubbery material. Conversely, a localized crossing of the coating layer causes insufficient adhesion of the rubbery material.
These two difficulties are precisely overcome by adjusting the amount of said overlay and / or the texture of the textile support so as to give them an overall permeability greater than 200 ml of air per minute evaluated for an area of 10 cm ² and a pressure difference of 5 millibars.

For the purposes of the present invention, the term "rubbery material" is intended to denote a material having as main component at least one natural or synthetic rubber or one of their mixtures.
According to a preferred variant of the invention, the rubbery or even elastomeric components are chosen so as to lead to a starting rubbery mixture having a Mooney index of between 40 and 80 estimated at a temperature of approximately 50 ° C.
This Mooney consistometric index actually corresponds to a torque value. The torque to be applied is determined under determined conditions for rotating a metal disc in a sealed cylindrical chamber filled with rubber material. The resistance of the rubber to this rotation, expressed in arbitrary units, is the Mooney consistency of the test piece.
The Mooney consistometric index is therefore the value of the torque exerted on the rotor, expressed in Mooney units, indicated by the device after a warm-up time of 1 minute followed by a rotor rotation time generally from 4 to 8 minutes. In the case of the present invention, this index is measured for a temperature of approximately 50 ° C. of the rotor. For more details, refer to the notice published by the French standard NFT43005 dated December 1991.
The rubber compounds suitable for the invention can be chosen from natural rubbers, synthetic rubbers based on styrene, butadiene and their mixtures.
In addition to its rubbery components, the initial mixture intended to constitute the expanded layer comprises at least one crosslinking system and one expansion system.
According to a particular variant of the invention, these systems are chosen so as to be active at the same temperature, between 150 ° C. and 210 ° C.
As regards more particularly the crosslinking system, it comprises at least one crosslinking agent, also called primary accelerator. This crosslinking agent preferably belongs to the family of thiazoles, quinones or quinones-dioximes.
It is preferably present in an amount of 0.5 to 8% by weight relative to the mass of the rubbery material to be transformed.

This primary accelerator is preferably associated with an agent known as a secondary accelerator.
This secondary accelerator preferably belongs to the family of metallic or non-metallic dithiocarbamates, metallic or non-metallic xanthates or also to the family of thiazoles.

This secondary accelerator is generally present at a rate of 0.2 to 2 % by weight and more preferably from 0.2 to 1.5% relative to the weight of the rubbery material.

Accélérateurs primaires - Famille des thiazoles ; Accélérateurs secondaires - Famille des dithiocarbamates ;

Accélérateurs primaires - Famille des thiazoles ; Accélérateurs secondaires - Famille des Xanthates ;

Accélérateurs primaires - Famille des quinones ou quinones-dioximes ; Accélérateurs secondaires - Famille des thiazoles.

By way of illustration of the crosslinking systems capable of being used in the claimed process, mention may be made of the following primary and secondary accelerating couples:

Primary accelerators - Thiazole family; Secondary accelerators - Dithiocarbamate family;

Primary accelerators - Thiazole family; Secondary accelerators - Xanthat family;

Primary accelerators - Family of quinones or quinones-dioximes; Secondary accelerators - Thiazole family.

The crosslinking system may be present in the mixture rubbery to be transformed at a rate of about 4 to 10% by weight relative to the weight of the rubbery material.

As regards the expansion system, it comprises at least one blowing agent. This swelling agent can belong to the family of azodicarbonamides or even to the family of sulfohydrazides.
The decomposition temperature of blowing agents related to azodicarbonamides varies between 160 and 210 ° C, as for blowing agents belonging to the sulfohydrazide family, their decomposition temperature is greater than 105 ° C.
These blowing agents are generally associated within the expansion system with at least one expansion regulator.
By way of representative of the expansion regulators suitable for the present invention, one can more particularly name urea and its derivatives, zinc-based compounds of zinc oxide, zinc stearate type, as well as amino compounds.
Generally the expansion system is incorporated in an amount of about 2 to 10% by weight of the rubbery material to be treated.

In addition to these essential components, the rubber material to be transformed can also incorporate other conventional additives such as anti-oxidation agents intended to prevent premature aging of the rubber mixture. It is also possible to incorporate charges of varying proportions. It can be reinforcing fillers such as kaolin or carbonate of magnesia or even carbon black. It can also be calcium carbonate or silicate or even ultra-fine silica. The fillers are in fact products which can be incorporated into said mixture without greatly lowering its mechanical qualities. By way of illustration of other fillers, mention may be made of chalk, kaolin, baryte sulphate, kieselguhr, talc and lithopone.
One or more plasticizers may also be incorporated into the rubber mixture. Oil-derived oils such as naphthenic, aromatic and / or aliphatic compounds, plasticizers of the phthalate family such as dioctyphthalate (DOP) and flame-retardant plasticizers of the phosphate and chlorinated paraffin type are particularly suitable as plasticizers.
In addition to these additives, the rubber mixture may include pigments for coloring the final material, odorants to combat the odor of vulcanized rubber, flame retardants for fire protection, hardeners to prevent deformation during certain types of manufacturing, retarders to sometimes moderate the too rapid action of accelerators, peptizers to soften rubber, etc.
The selection of these additives as well as the adjustment of their respective proportions in the rubber mixture to be transformed is of course the skill of the skilled person.

The coated and expanded textile can also be protected at its level. coated side. This protection can be ensured by applying a varnish especially of acrylic type, of a silicone-based resin or a treatment fluorinated. Depending on the desired effect, the protective varnish can be colorless or colored but translucent to reveal the printed pattern (s).

The coated and expanded textile obtained according to the invention has in particular great flexibility as well as good resistance to aging, weathering, ultraviolet radiation as well as food stains.
“Stain-resistant” additives of known type can be introduced, for example, into the final protective varnish to increase the stain-resistant power of the coated textile, for example with regard to food stains.
The invention applies more particularly to the manufacture of coated tablecloths or other articles intended for the tableware or also to articles intended for interior decoration in particular the wall textile.

The invention will now be illustrated with the aid of an example and a figure which should not be considered as limiting.

FIGURE:

1) désigne la couche expansée

2) représente le support textile et,

3) figure la couche d'enduction.

Figure 1 is a schematic representation of a coated and expanded textile:

1) designates the expanded layer

2) represents the textile support and,

3) shows the coating layer.

EXAMPLE 1:

1) Utilisation d'un tissu coton imprimé ou uni d'un poids de 120 g/m² pour la couche support.

2) Enduction à la racle sur le support d'une résine acrylique d'un poids de 15 g/m². Séchage et réticulation à 160°C. Formule : - Suspension résine acrylique (60 % E.S.) 50-75 - Suspension résine polyuréthane aliphatique (40% E.S.) 25-50 - Epaississant 2-6 - Polymère fluoré 5-15 - Agent de réticulation (dérivé ethérifié de mélasmine formoldehyde) 1-6 - Antimousse 0.5-2

3) Calandrage au verso du support enduit d'un matériau caoutchouteux. Composition du mélange caoutchouteux utilisé : en poids * Caoutchouc naturel type SMR CV 100 * Peptisant (dibenzyl amidodiphényl disulfure) 0,1 - 0,2 * Factice 5 - 15 * Craie 20 - 60 * Kaolin 10 - 30 * Plastifiant naphténique 30 - 50 * Paraffine 1 - 4 * ZnO 5 - 10 * Acide stéarique 1 - 3 * Agents de protection 1 - 3 * Soufre 1 - 2,5 * Diéthyl dithiocarbamate de zinc 0,3 - 1,4 * Disulfure de benzothiazyle 1 - 2,5 * Agent gonflant type Sulfohydrazide 4 - 10 * Urée 4 - 10 La bande ainsi obtenue est dirigée vers un tunnel d'expansion et de réticulation porté à une température de 180°C. La bande défile de manière continue à travers cette enceinte de manière à ce que son temps de séjour n'y excède pas 5 minutes. La sortie du tunnel est refroidie et le tissu enduit expansé est récupéré. Selon une variante de réalisation, la bande est grainée avant d'entrer dans le tunnel d'expansion.

4) Enduction sur la face enduite d'un vernis de type acrylique contenant des additifs pour le rendre anti-tache. Dépôt de 20 g/m² d'une solution à 15% d'extrait sec. Séchage et réticulation à 160°C.

The different production phases of a printed coated tablecloth are as follows:

1) Use of a printed or plain cotton fabric with a weight of 120 g / m ² for the support layer.

2) Coating with a doctor blade on the support of an acrylic resin weighing 15 g / m ² . Drying and crosslinking at 160 ° C. Formula : - Suspension acrylic resin (60% ES) 50-75 - Suspension polyurethane aliphatic resin (40% ES) 25-50 - Thickener 2-6 - Fluorinated polymer 5-15 - Crosslinking agent (etherified derivative of melasmin formoldehyde) 1-6 - Antifoam 0.5-2

3) Calendering on the back of the support coated with a rubbery material. Composition of the rubber mixture used: in weight * Natural rubber type SMR CV 100 * Pepticant (dibenzyl amidodiphenyl disulfide) 0.1 - 0.2 * Dummy 5 - 15 * Chalk 20 - 60 * Kaolin 10 - 30 * Naphthenic plasticizer 30 - 50 * Paraffin 1 - 4 * ZnO 5 - 10 * Stearic acid 1 - 3 * Protection agents 1 - 3 * Sulfur 1 - 2.5 * Zinc diethyl dithiocarbamate 0.3 - 1.4 * Benzothiazyl disulfide 1 - 2.5 * Sulfohydrazide blowing agent 4 - 10 * Urea 4 - 10 The strip thus obtained is directed to an expansion and crosslinking tunnel brought to a temperature of 180 ° C. The strip runs continuously through this enclosure so that its residence time does not exceed 5 minutes. The tunnel exit is cooled and the expanded coated fabric is recovered. According to an alternative embodiment, the strip is grained before entering the expansion tunnel.

4) Coating on the coated side of an acrylic varnish containing additives to make it stain-resistant. Deposit of 20 g / m ² of a 15% solution of dry extract. Drying and crosslinking at 160 ° C.

Claims (8)

Process for the preparation of a coated and expanded textile, characterized in that : there is a textile forming a support comprising a first face and a second face and, where appropriate, having patterns printed on its second face, a coating material is deposited on the second face of the textile support, the crosslinking of the coating material is carried out, a rubbery material is deposited on the first face of the textile support, crosslinking and expanding the rubbery material successively or simultaneously, and a protective treatment of the coated face of the textile is optionally carried out. Method according to claim 1, characterized in that the first coating layer is applied at a rate of approximately 10 to 25 g / m ² on the surface of the first face of the second layer. Method according to claim 1 or 2 characterized in that the weight ratio coating layer / textile support is between 5 and 15 and preferably 7 and 12. Method according to one of claims 1 to 3 characterized in that the coating layer is based on at least one acrylic resin, polyurethane or one of their mixtures. Method according to any one of Claims 1 to 4, characterized in that the textile support comprises or consists of a fabric, a nonwoven or a mesh. Method according to any one of claims 1 to 5, characterized in that the textile support has a texture of 24x24 threads per cm for a title of 34x34 metric numbers. Method according to any one of Claims 1 to 6, characterized in that the textile support is dyed or has a printed face. Process according to any one of Claims 1 to 7, characterized in that the components of the rubbery material of the first layer are chosen so as to lead to a starting rubbery mixture having a MOONEY index of between 40 and 80 estimated at a temperature about 50 ° C.

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