WO2001064996A1 - Method for producing a plastic floor covering - Google Patents

Abstract

The invention concerns a method for producing a floor covering which consists in: in a first operational phase, classically producing a base structure (1b) with plasiticized PVC, by pressing, calendering, extrusion or coating, optionally reinforced with a textile core and associated with an additional backing (1a); then in a second operational phase, producing a surface covering consisting of a double-layer complex comprising a thermoplastic layer coated with a thermosetting polymer film. The invention is characterised in that said double-layer complex is formed, either continuously and in line with the production of the base structure, or on a transfer support enabling complexing in a subsequent phase by: depositing on the upper surface of the base complex, or on a transfer support, a transparent or coloured layer (2) of PVC plastisol which is pre-gelled by heat treatment; continuously coating the pre-gelled plastisol layer (2) with thermosetting powder (7) and heat treatment transforming the powder into a continuous liquid film (9); passing the resulting complex in a warm air furnace (11), bringing about gelling and crosslinking of the two constituents (2, 9) of the surface layer.

Description

PLASTIC MATERIAL.

Technical Field The present invention relates to a process for producing a plastic floor covering making it possible not only to obtain very good surface characteristics, but also not to alter the characteristics of the basic structure constituting said structure. coating.

Previous techniques

It has been proposed for a long time to produce flexible floor coverings, made of plastic.

In general, such floor coverings consist of a thermoplastic base structure, in particular made of plasticized PNC, obtained by pressing or calendering. This basic structure can possibly be reinforced by a textile structure embedded in the mass of the material.

Furthermore, to improve comfort or impart specific characteristics to the covering for its use, this basic structure can be associated with an underlay, for example a foam underlay.

In addition, the visible face is covered with a finishing layer giving the set of specific properties such as resistance to UN, resistance to fouling, scratching, traffic, abrasion, black traces of shoes (scuffmg), with cigarette burn.

It is desirable that such coatings can exhibit resistance to specific stains which may occur at the place of use, for example in the hospital field (alcoholic iodine stains, alcoholic eosin, etc.).

Finally, it is also desirable to suppress the emissions of volatile organic compounds, which can be obtained by the barrier effect of the upper surface layer. our ra ser a couc ee on ace e te s t coverings e soil, it has been envisaged for a very long time, as is clear in particular from FR 2 341 021, to use a composition either based on a thermoplastic material, PVC possibly loaded, either with a thermosetting material in crosslinked polyurethane in particular.

The process described in this document is however complex to implement.

Numerous proposals have also been made to produce surface layers produced from different synthetic polymers as is apparent from FUS 4,337,296, from EP 794,281, from GB 2,285,012.

In all of these proposals, the problem that arises is that of being able to achieve good adhesion between the surface layer of thermosetting material and the thermoplastic base structure, as well as not to alter the characteristics of this base structure.

However, we have found, and this is what is the subject of the present invention, an improved method which makes it possible to solve all of these problems.

Statement of the invention

In general, the method according to the invention for producing a floor covering consists of:

"in a first operational phase, to produce in a conventional manner a basic structure in plasticized PNC, by pressing, calendering, extrusion or coating, possibly reinforced by a textile reinforcement and / or associated with an additional undercoat; then

¹ in a second operating phase, to produce a surface coating consisting of a two-layer complex comprising a thermoplastic layer coated with a film based on a thermosetting polymer.

In the process according to the invention, the two-layer complex constituting the surface coating is formed, either continuously and in line with the production of the basic structure, or on a transfer support allowing complexing during a subsequent phase by : "pt on a ace sup r eure u base complex, or on a transfer support, a layer of PNC plastisol, transparent or colored, which is pre-gelified by heat treatment;

"continuously, covering the layer of pre-gelled plastisol with a layer of thermosetting powder followed by a heat treatment transforming said powder into a continuous liquid film;

passage of the complex thus formed in a hot air oven, resulting in gelation and final crosslinking of the two constituents of the surface layer, the assembly then possibly being seeded and received.

For the implementation of this process, the PNC-based thermoplastic layer of the surface complex is obtained from a composition of PVC plastisol (PVC resin, plasticizer, and conventional stabilizing and rheology additives), this layer of surface being colored or transparent and having a thickness of between 0.1 and 2 mm and preferably 0.2 to 0.8 mm. This plastisol can also be produced using acrylic resin in a plasticizer.

The plastisol is then pregelified by heat treatment at a temperature between 120 ° C and 130 ° C for thirty to sixty seconds by passing through a hot or infrared oven.

The outer layer associated with this PVC-based layer, for its part, is produced from a thermosetting powder composition having short-term crosslinking (hardening) characteristics, between one and seven minutes at most at 210 °. vs.

The formulation of this powder is such that it allows adhesion to the plasticized polymer (PVC) without altering the qualities of flexibility, the hardener also being non-aggressive with respect to PVC.

Such a powder can be obtained from a composition comprising: "a hydroxylated polyester resin, a carboxylated polyester resin, a polyurethane resin, a polyester / epoxy hybrid resin, etc .; "a glycidylester type crosslinker, a hydroxyalkylamide type crosslinker, a blocked or dimerized isocyanate type crosslinker.

The deposition of the thermosetting powder is preferably carried out by electrostatic dusting at a rate of 20 to 200 g / m 2.

This powder is transformed into a liquid film by a heat treatment carried out by combining the action of a ramp with infrared radiation followed by passage through a hot air tunnel.

Such a procedure makes it possible to form a very regular and continuous film which is explained by the fact that the infrared radiation causes a rapid melting of the powder and that the action of hot air results in the smoothing of the film.

This heat treatment is a function of the nature of the thermosetting powder, the infrared radiation bringing the latter to a temperature between 110 ° C and 200 ° C for a period of between one to thirty seconds, while the hot air treatment is carried out. at a temperature which can vary from 80 to 120 ° C for a period of thirty seconds to one minute.

After treatment, the surface film of thermosetting polymer, preferably based on copolyester, has a thickness of between 15 and 150 μm and preferably between 30 and 80 μm.

Brief description of the drawings

The invention and the advantages which it brings will however be better understood thanks to the description which follows and which is illustrated by the appended diagrams in which:

_ Figure 1 is a schematic view of a production line of a floor covering according to the invention; _ Figure 2 is a schematic perspective view illustrating the general structure of such a floor covering. Man re era ser nvention

In the following description, the invention will be described for producing a continuous surface coating with the production of the basic structure of the floor covering, it being understood that this surface layer could be produced during a separate phase on a transfer support to be associated with the base layer during the formation of the latter.

Referring to the appended figures, in a first operational phase, a basic structure (1) is made of PVC, by pressing, calendering, extrusion or coating.

Such a basic structure (1) can be reinforced by a layer of textile material, and can comprise on its reverse side, an under-layer such as a layer of foam (la).

In accordance with the invention, the surface coating of the base complex (1) thus formed is produced by depositing on the upper face of this support (1), a regular layer (2) of a plastisol based on a thermoplastic material, PVC in particular, but which can also be an acrylic plastisol.

This plastisol deposition is carried out in a conventional manner by passing the support (1) over a roller (3) associated with a doctor blade (4).

The plastisol layer (2) has a thickness of between 0.2 and 0.8 mm.

The assembly is continuously subjected to a gelation heat treatment bringing the material to a temperature between 120 and 130 ° C for 30 to 60 seconds by passage through a hot air or infrared oven (5).

A thermosetting powder composition (7) is then deposited on this pregastified and therefore hardened plastisol layer (2).

This deposition is carried out by electrostatic dusting by means of a dusting system which can be a hopper (6) associated with an electrostatic charge assembly or an electrostatic spraying system suitable for dusting at p at. ep es ras ra son egm, e presence between and 100 g / m ² .

The powder is then transformed into a continuous liquid film (9) by a heat treatment (8). This heat treatment combines both the action of an infrared ramp causing the powder to melt, followed by passage through a hot air tunnel resulting in a smoothing of the film formed.

Depending on the nature of the powder, the infrared radiation brings the latter to a temperature between 110 ° C and 200 ° C, and this for a period of one to thirty seconds, while the passage through hot air, brought at a temperature between 80 and 120 ° C, is carried out for a period of thirty seconds to one minute.

The thickness of the film is between 15 μm and 150 μm, preferably between

30 and 80 μm.

The complex thus formed is then subjected to a heat treatment inside a hot air oven (11), resulting in gelation and final crosslinking of the two constituents (2,9) of the surface layer.

The temperature inside the oven is set between 200 ° C and 210 ° C, the treatment time being between one to seven minutes.

The complex thus formed is then received, for example in the form of a coil.

Figure 2 shows in section, schematically, the general structure of such a floor covering, therefore comprising a base support (1) covered with a transparent bilayer structure consisting, on the one hand, of a thermoplastic layer (2), preferably made of plasticized PVC, associated with a film (9) based on a thermosetting material, in particular polyester.

As can be seen from this figure, in such a complex, the different layers are intimately linked to each other without, however, interpenetration constituents of one of the layers in the adjacent layer, which makes it possible to preserve all the characteristics of each of the layers.

Example By means of an installation as described above, the surface covering of a basic structure (1) previously produced, comprising a foam underlay (la) associated with the back of a sheet ( lb) PVC possibly reinforced by a textile structure.

Such a support (1) has a thickness of 15 mm.

On the surface of this support (1), a layer of 625 g / m ² of a plastisol having a viscosity of 10 Pa.s (10,000 cPs) is deposited with a doctor blade (4) for a shear of 100 s ^~ l using Rheomat equipment having the following composition:

_ polyvinyl chloride (100 parts) _ plasticizer of dioctyl phthalate type (DOP) at 40 pcr _ stabilizer of butyltin type sulfur at 2 pcr _ diluent.

A layer having a thickness of 0.5 mm is thus formed on the surface of the support (1).

The assembly is then subjected to a heat treatment by passing under an infrared ramp (5) bringing the material to a temperature of 110 ° C. causing the pre-gelling, therefore the hardening of this layer.

Downstream of the infrared ramp, a thermosetting powder consisting of a copolyester-based composition comprising: 60 g / m ² is deposited

• hydroxylated polyester type resin

• dimerized isocyanate type hardener.

The complex is subjected to a second heat treatment (8) combining the action of an infrared ramp bringing the material to 120 ° C. for ten seconds, following a treatment in an arc tunnel at port for a period of forty seconds, making it possible to obtain a film (9) having a thickness of the order of 50 μm.

The coating thus formed then passes through a hot air oven (11) brought to a temperature of 200 ° C., the treatment time being 3 minutes.

At the outlet of the installation, a floor covering is obtained as illustrated in FIG. 2, having a total thickness of 2 mm.

Such a floor covering has very good surface properties, in particular with regard to resistance to fouling, scratching, abrasion, traffic and UN.

It also has very good stain resistance.

Claims

1 / Process for producing a floor covering which consists of: "in a first operational phase, to produce in a conventional manner a basic structure (lb) in plasticized PNC, by pressing, calendering, extrusion or coating, possibly reinforced by a textile reinforcement and associated with an additional sub-layer (la); then "in a second operational phase, to produce a surface coating consisting of a bilayer complex comprising a thermoplastic layer coated with a film based on a thermosetting polymer, characterized in that said bilayer complex is formed, either continuously and in line with the production of the basic structure, either on a transfer support allowing complexing during a subsequent phase by: • deposition on the upper face of the base complex, or on a transfer support, of a layer (2) of PNC plastisol, transparent or colored, which is pre-gelified by heat treatment; • continuous, covering of the pre-gelled plastisol layer (2) with a layer of thermosetting powder (7) followed by heat treatment (8) transforming said powder into a continuous liquid film (9); . passage of the complex thus formed in a hot air oven (11), resulting in gelation and final crosslinking of the two constituents (2,9) of the surface layer. 2 / A method according to claim 1, characterized in that the heat treatment (8) transforming the powder into a continuous liquid film (9), is carried out by the combination of the action of an infrared ramp causing the fusion of said powder, followed by treatment in a hot air tunnel smoothing the film formed. 3 / Method according to one of claims 1 and 2, characterized in that: "the thickness of the plastisol layer (2) is between 0.2 and 0.8 mm; "the deposition of thermosetting powder being carried out by electrostatic dusting at a rate of 20 to 200 g / m ² ; '' the continuous quid lm formed after heat treatment (8) has a thickness between 15 μm and 150 μm and preferably between 30 and 80 μm. 4 / Method according to one of claims 1 to 3, characterized in that: "the first pre-gelling heat treatment is carried out at a temperature between 120 and 130 ° C for 30 to 60 seconds by passage through a hot air or infrared oven (5), • the second heat treatment (8) causing the formation of the film (9) is carried out by the action of an infrared ramp bringing the powder to a temperature between 110 and 200 ° C for one to thirty seconds, the hot air treatment being carried out at a temperature between 80 and 120 ° C for a period of thirty seconds to one minute; • the final gelification and crosslinking treatment of the complex is carried out inside a hot air oven (11) brought to a temperature of 200 ° C, the treatment time being 3 minutes.