EP0209810B1 - Process for making floor or wall coverings with a crackled effect, and the product obtained - Google Patents

Description

The present invention relates to a process for producing floor coverings or wall coverings, of the synthetic coverings type, with a cracked effect. It also extends to the products obtained by this process.

In the production of synthetic decorative coatings for floors and walls, we are increasingly seeking to approach the decorations obtained with conventional materials such as ceramics and the like. A particular decorative effect achieved by ceramic materials lies in cracks that are difficult to obtain with synthetic materials deposited in the coating state, for example, on a conventional support. The reproduction of cracks by printing has the drawback of not allowing a good imitation of the "natural" cracked effect and the patterns obtained are necessarily repetitive without randomness. In addition, printing does not give a depth effect (relief) to the material.

Document FR-A-2 126 658 discloses a method for applying an emulsion coating material to produce cracking patterns. In this case, a lower coating synthetic material containing a mineral material having a high swelling property is deposited, this lower coating material is dried and then a cured coating material containing a silicon dioxide sol is applied. In the process according to the cited document, the lower coating material absorbs the water contained in the hardened coating material, simultaneously causing it to contract, and also, jointly, cracks. A drawback of the process lies in the fact that there are two different layers of particular composition to be used, which require intermediate drying. This process is necessarily slow and expensive.

Document FR-A-2 247 494 relates to a cracked film of polymer based on PVC and at least one plasticizer distributed in a homogeneous manner. It also claims a coating consisting of a conventional support coated with such a film as well as a process for the preparation thereof. The process uses a two-phase system, namely polymer / plasticizer and water. However, this process does not allow sufficient control of the formation of cracks and the opening thereof. Furthermore, this process requires high amounts of water.

Document US-A-2 612 456 also relates to a process for the manufacture of a decorative and protective coating which has a cracked appearance in which an organosol is used comprising particles of a copolymer of organic vinyl chloride and of acetate, dispersed in a volatile organic liquid. The liquid used must have a swelling effect on the polymer particles. This process is also difficult to control and makes it difficult to obtain a dense network of cracks. Furthermore, this process also requires high amounts of solvent.

An object of the present invention is to provide a process for the production of floor coverings or wall coverings, with a cracked effect requiring only a single layer to obtain said cracked effect.

Another object of the present invention is to provide a process for the production of cracked floor or wall coverings, in which the amounts of solvent or water required are significantly reduced compared to the state of the art.

Another object of the present invention is to provide a process for producing deep cracked floor or wall coverings, that is to say in substantially the whole mass of at least one layer of the covering.

According to another aspect of the present invention, the aim is to provide a new product, that is to say a new floor or wall covering having a cracked effect, of random nature.

• une composition d'enduction d'un plastosol contenant un gel préalablement préparé à partir d'un couple constitué par un agent sorbant solide et par un solvant qui provoque le gonflement par absorption dudit solvant dans et sur l'agent sorbant ou bien,
• une dispersion dans l'eau d'un mélange sec de PVC et de plastifiant contenant au moins une résine formant gel dans l'eau en ce qu'on effectue ensuite un traitement thermique de formation de film ou de séchage à une température suffisante pour que se produise concomitamment un processus irréversible de prégélification de l'enduction et la rétraction du gel par désorption du solvant de l'agent sorbant ou par évaporation de l'eau, respectivement, et en ce qu'on effectue ensuite, éventuellement les opérations classiques de finition.

According to the invention, the process for the production of floor coverings or wall coverings, with a cracked effect and characterized in that it is deposited on a compatible support,

• a composition for coating a plastosol containing a gel previously prepared from a pair consisting of a solid sorbent and a solvent which causes swelling by absorption of said solvent in and on the sorbent or else,
• a dispersion in water of a dry mixture of PVC and plasticizer containing at least one gel-forming resin in water, in which a thermal treatment of film formation or drying is then carried out at a temperature sufficient for an irreversible process of pregelification of the coating and the retraction of the gel occurs concomitantly by desorption of the solvent of the sorbent agent or by evaporation of the water, respectively, and in what is then carried out, optionally the conventional operations of finish.

The process of the invention makes it possible to achieve the aims of the invention and in particular makes it possible to produce a coating with a cracked effect, in which the cracks extend randomly, in depth, in the mass.

The invention also resides in the choice of the sorbent agent / solvent pair used in the particular conditions of the process of the invention. Advantageously, the solvent does not disturb the plasticizing effect of the other additives of the synthetic material used for the manufacture of the coating according to the invention. It is obvious that a solvent which does not participate in the plasticization is preferably used, although the use of such a solvent cannot be excluded.

According to a particularly preferred embodiment of the invention, the absorbent agent is a silica or a silicate, preferably having a specific surface according to BET of between 250 and 700 m ² / g, preferably of the order of 300 at 400 m ² / g. The coating composition advantageously comprises 0.5 to 15% by weight of sorbent agent.

Preferably, a solvent is used whose vapor pressure is very high at the formation temperature of the synthetic film, so that the sorbent shrinks by desorption of the solvent once the film is formed, in order to " tear "forming cracks. It is understood that the temperature at which the solvent has a high vapor pressure, or the boiling temperature of the solvent, must be close to the film-forming temperature, because, if this temperature is too high, it does not there will be no cracking, due to the fusion and the surface tension of the synthetic coating. On the other hand, if this temperature is too low, there is evaporation before the film is formed. It is, of course, necessary to ensure that the retraction force is greater than the cohesive force of the film. Advantageously, a solvent such as the hydrocarbon fractions and in particular white spirit is used at a rate of the order of 15 to 35% by weight of the plastisol coating.

• - des solvants du type SHELLSOL® TD ou AB
• - des fractions d'hydrocarbures autres que le white spirit ayant des propriétés d'évaporation/rétention convenables
• - des solvants du type POLYSOLVAN® a savoir des esters n-butyle du glycol
• - des solvants du type DOWANOL DPN^O à savoir l'éther méthylique de dipropylèneglycol.

The following products can also be used as solvent:

• - solvents of the SHELLSOL® TD or AB type
• - hydrocarbon fractions other than white spirit having suitable evaporation / retention properties
• - solvents of the POLYSOLVAN® type, namely n-butyl esters of glycol
• - solvents of the DOWANOL DPN ^O type, namely dipropylene glycol methyl ether.

Advantageously, the temperature for forming the plastisol coating film is chosen between 110 and 160 ° C. The coating can be subjected subsequently, for example at a temperature of the order of 200 ° C. for 1 minute to 2 minutes 30 seconds if it is desired to modify the initial opening of the cracks without affecting their number.

In the case of the application to the support of a dispersion in water of a dry mixture of PVC and plasticizer, the gel-forming resin in the presence of water can be chosen from a wide range of commercial products. For reasons of compatibility with the medium used and the support on which it is coated, preference is given to mixtures based on cellulosic resin with thickening action.

The addition of a solvating agent such as ethyl glycol to water is particularly useful in causing the gel-forming resin to swell.

The additives necessary for stabilizing the aqueous dispersion are well known in the art and a large amount of commercial products are available. It will preferably be added to the preparation in addition to surface-active agents serving for the stabilization of the anti-foaming agents to facilitate the preparation of the dispersion and to be able to carry out a regular coating.

The preparation of the dispersion advantageously includes the presence of fillers, pigmented or not, which act in particular on the extent of the cracks or cracks observed.

Advantageously, the drying heat treatment temperature is chosen between 180 and 210 ° C. The coating can subsequently be subjected, for example to a temperature of the order of 20 ° C for 1 minute to 2 minutes 30 seconds if it you want to change the initial opening of the cracks without affecting their number.

According to one embodiment of the invention, the support on which the plastisol coating composition containing said sorbent / solvent couple is applied or the aqueous dispersion of a dry mixture of PVC and plasticizer containing a gel-forming resin in water may consist of a conventional support which possibly already includes one or more deposits of synthetic material, possibly provided with a print.

It is possible, according to the invention, in order to obtain particular decorative effects, to apply the PVC plastisol coating composition containing the sorbent / solvent couple or the aqueous dispersion of PVC and of a gel-forming resin. locally so that only part of the decorative pattern has a "cracked" appearance. This discontinuous application can be carried out by well-known techniques, for example by a screen printing technique. It thus becomes possible to imitate in particular floor or wall coverings comprising cracked effect tiles and comprising joints imitating cement joints which are not cracked.

According to an advantageous embodiment of the present invention, it is possible, after formation of the cracks, to scrape off a coating of plastisol, for example on the coating obtained, so as to fill the cracks with a suitable material. According to a particularly preferred embodiment, it is possible to scrape off a plastisol containing up to 30% of carbon black on the product obtained or optionally an aqueous emulsion of plasticized PVC and conductive carbon black, so as to fill the cracks by a material conducting the electric current. Such a coating is particularly suitable for avoiding the formation of static electricity for coatings intended for operating rooms, computer rooms, etc. The use of such a composition containing carbon black makes it possible to increase to a value of the order of 10 ⁸ ohm.cm the electrical transverse resistance of the coating obtained which is normally 10 ¹⁴ ohm.cm.

It is also advantageous, depending on the desired effects, to carry out a printing or any other conventional operation on the cracked product. According to one embodiment, it is also possible to coat in the cracks a conventional foamable paste which, during the heat treatment, undergoes swelling by producing a veining emerging on the surface by imitating a wall plaster.

To finish, it is possible to deposit a coating of a conventional wear layer on the surface which further improves the service life of such a coating obtained according to the various embodiments mentioned above. the invention.

The shape, depth and opening of the cracks can be controlled by the temperature of the heat treatment, by the choice of the sorbent / solvent couple and of the resin forming gel in water and by the quantity of solvent used. It should be noted, however, that the depth and the opening of the cracks can be markedly modified later, notably by heat treatment, unless these have been coated beforehand.

The other stages of a conventional type which can be implemented on the cracked product obtained according to the present invention, need not be described in more detail in the present specification. Let us simply note, by way of example, deposits of pigmented coating or not, impressions, deposits of wear layer, conventional heat treatments and final baking.

The present invention is described in more detail in support of the following examples in which all the proportions are expressed by weight unless otherwise indicated.

Example 1

• - 100 parties d'acétate de butyl-glycol
• - 10 parties de silice pyrogénée (300 m²/g)-Aerosil® 300.

A gel composed of:

• - 100 parts of butyl glycol acetate
• - 10 parts of fumed silica (300 m ² / g) -Aerosil® 300.

• - 650 parties de PVC en émulsion (par exemple valeur K 72)
• - 100 parties de PVC en suspension (par exemple: valeur K 66)
• - 540 parties de plastifiant phtalate
• - 500 parties de charges carbonatées (carbonate de calcium)
• - 25 parties d'oxyde de titane
• - 2 parties de stabilisant à l'étain.

A so-called "compact" plastisol composition is also prepared containing:

• - 650 parts of PVC in emulsion (for example K 72 value)
• - 100 parts of PVC in suspension (for example: K value 66)
• - 540 parts of phthalate plasticizer
• - 500 parts of carbonate fillers (calcium carbonate)
• - 25 parts of titanium oxide
• - 2 parts of tin stabilizer.

• - 70 parties de "compact"
• - 35 parties de gel
• - 10 parties de TXIB (texanol isobutyrate - plastifiant secondaire)
• - 3,5 parties de stabilisant au baryum et au zinc.

The “compact” composition and the gel previously prepared are then mixed as follows:

• - 70 parts of "compact"
• - 35 parts of gel
• - 10 parts of TXIB (texanol isobutyrate - secondary plasticizer)
• - 3.5 parts of barium and zinc stabilizer.

The levels of Aerosil 300® and of solvent are respectively 2.68% and 26.31% in the plastisol coating. The coating thus obtained is applied to a conventional support having possibly already received at least one coating and / or one impression.

The product thus obtained is subjected to a heat treatment so as to create cracks, which advantageously consists of passing, for 2 minutes 30 seconds, at a temperature between 110 and 120 ° C, obtained by heating in particular using a forced air oven or infrared radiation or a combination of the two, for example.

The product obtained is then optionally subjected to an impression of a decoration, according to a process known per se.

The product can also be subjected to a second heat treatment which allows the opening of already formed cracks. Such a heat treatment consists in passing, for 1 minute to 2 minutes 30 seconds, at a temperature of the order of 200 ° C.

The product is then passed under a rubber doctor blade which penetrates, inside the cracks, a pigmented fluid plastisol which then undergoes pre-gelification.

It is surprisingly found that after coating with a plastisol, the cracks no longer open during this pregelling.

The whole is covered with a coating of PVC plastisol serving as a wear layer and the product obtained is subjected to a gelling operation, for 2 minutes 30 seconds, at a temperature of the order of 190 ° C.

It is also possible to use a polyurethane varnish which can be crosslinked by any suitable means, for example UV or by electron beam.

Example 2: plastisol gel

• - 80 parties de white spirit
• - 35 parties de silicate de baryum tel que le Dutch Boy BAROSIL^O (produit de la National Lead Inc. USA).

A gel composed of:

• - 80 parts of white spirit
• - 35 parts of barium silicate such as the Dutch Boy BAROSIL ^O (product of the National Lead Inc. USA).

• - 50 parties de composition "compact",
• - 35 parties de gel.

A “compact” composition similar to that of Example 1 is also prepared and the gel previously prepared is incorporated therein at the rate of:

• - 50 parts of "compact" composition,
• - 35 parts of gel.

The rate of Barosil ^O and white spirit in the coating is, respectively, 12.5% and 28.7%.

The coating thus obtained is deposited on a conventional support which is subjected to a heat treatment so as to create cracks. Said heat treatment consists of a passage of 2 minutes at 110 - 120 ° C, in an oven for example. The product thus obtained is then passed under a doctor blade so as to penetrate, inside the cracks, a PVC paste containing 30% carbon black. A final baking heat treatment is then carried out. A so-called "homogeneous" coating is obtained, the transverse electrical surface resistance of which is lowered to a value of the order of 108 ohm.cm (whereas it is 10 ¹⁴ ohm.cm for PVC) and which therefore makes it possible to disperse local electrical charges. Such a coating could be used in an environment with high sensitivity to local loads such as computer rooms.

Example 3: plastisol gel

• - 10 parties en poids d'Aerosil^e 300
• - 100 parties en poids de white spirit.

A gel composed of:

• - 10 parts by weight of Aerosil ^e 300
• - 100 parts by weight of white spirit.

A compact plastisol "composition is prepared according to Example 1.

• - 70 parties de "compact"
• - 37 parties de gel
• - 10 parties de TXIB

Then we mix:

• - 70 parts of "compact"
• - 37 parts of gel
• - 10 parts of TXIB

We then proceed as in Example 1.

Example 4: plastisol gel

• - 30 parties de PVC suspension de valeur K = 66
• - 70 parties de PVC émulsion de valeur K = 70
• - 32 parties de plastifiant phtalate
• - 20 parties de TXIB
• - 25 parties de charges (carbonate de calcium)
• - 2 parties de Ti0₂
• - 2 parties d'agent gonflant autodispersant

The procedure is as in Example 1 or 2, but a foamable paste of the following composition is coated in the cracks obtained:

• - 30 parts of PVC suspension of value K = 66
• - 70 parts of PVC emulsion of value K = 70
• - 32 parts of phthalate plasticizer
• - 20 parts of TXIB
• - 25 parts of fillers (calcium carbonate)
• - 2 parts of Ti0 ₂
• - 2 parts of self-dispersing blowing agent

Example 5 (comparative example)

• Les figures 1 à 3 représentent, en abscisse, les frequences (en Hz) et, en ordonnée, le module G" (module de dissipation) en N/m².
• Les figures 4 à 6 représentent, en abscisse, les fréquences (en Hz), et en ordonnée le module K (module de raideur) en N/m.
• Les figures 1 et 4 se rapportent à une composition "compact" selon l'exemple 1.
• Les figures 2 et 5 se rapportent à la composition suivante:
  

The annexed diagrams show the results of laboratory tests using the annular pumping technique.

• Figures 1 to 3 represent, on the abscissa, the frequencies (in Hz) and, on the ordinate, the module G "(dissipation module) in N / m ² .
• Figures 4 to 6 represent, on the abscissa, the frequencies (in Hz), and on the ordinate the module K (stiffness module) in N / m.
• Figures 1 and 4 relate to a "compact" composition according to Example 1.
• Figures 2 and 5 relate to the following composition:
  

FIGS. 3 and 6 relate to a composition as mentioned below in which the gel has been prepared beforehand, that is to say:

The gel consists of 63 parts of Aerosil® 300 and 637 parts of white spirit.

As the module G ″ (FIGS. 1 to 3) is proportional to the viscosity and the frequency is proportional to the speed gradient, the annular pumping makes it possible to express the viscosity as a function of the speed gradient.

We can read figures that the composition of Figure 3 has the highest viscosity level, while for a composition having the same overall contents, but in which we have not added silica and white spirit in the form of gel, the viscosity level is very low (= fig. 2).

We can conclude that in the case of FIG. 2, the white spirit is not preferentially adsorbed by the silica but is also distributed in the medium and therefore has a viscosity-lowering effect on the plastisol. In the case of FIG. 3, on the other hand, the solvent swelled the inert charge and remained there even after mixing in the final medium. It has not been used to lower the general viscosity of plastisol. It is only the heat treatment which will make it possible to desorb the solvent from the silica by causing it to shrink.

Figures 4 to 6 relating to the stiffness (module K) also confirm this behavior, for the same compositions.

Example 6: aqueous dispersion.

In a rapid mixer (Papenmeier type), a dry PVC mixture is prepared consisting of:

When the mixture reaches the temperature of 80 - 90 ° C, it is transferred to the cooling tank. To obtain an improved flow mixture, add 3 to 5 parts of PVC "emulsion" during cooling.

Cette supension aqueuse est déposée à la racle sur un support composé d'un voile de verre enduit d'un plastisol de PVC gélifié sur tambour et qul possède la formulation suivante:

An aqueous suspension prepared in a mixer (Moltini type) consists of:

This aqueous suspension is deposited with a doctor blade on a support composed of a glass veil coated with a PVC plastisol gelified on a drum and which has the following formulation:

This coating is dried and baked in a hot air oven between 130 and 210 ° C.

During cooking a tight and continuous network of cracks appears.

Example 7: aqueous dispersion

Starting from the dry PVC mixture of the same formulation as in Example 1, an aqueous suspension of the following formulation is prepared:

This suspension is scraped on a support identical to that of Example 1, dried and baked in a hot air oven under the same conditions.

During cooking, a discontinuous and sparse network of fine cracks develops.

• -^* impression suivie d'un vernissage
• -• enduction d'un vernis coloré, translucide ou non
• -^* enduction conductrice

Each type of product can be further processed in different ways to ensure the finish, for example by:

• - ^* printing followed by a vernissage
• - • coating of a colored varnish, translucent or not
• - ^* conductive coating

In addition, the various aqueous suspensions can be colored in the mass by adding an adequate pigment to their formulation.

Claims (17)

1. Verfahren zum Herstellen von Boden- oder Wandbeschichtungen mit Craquele-Effekt, dadurch gekennzeichnet, daß auf eine kompatiblen Unterlage:

Unterlage:

- ein Plastisol-Uberzugsgemisch aufgebracht wird, das ein Gel enthält, das zuvor aus einem festen Sorptionsmittel und einem Lösungsmittel hergestellt wurde, wobei dieses Gel infolge Absorption des besagten Lösungsmittels in und auf dem Sorptionsmittel die Aufblähung hervorruft;

- oder eine wässerige Dispersion eines trockenen Gemischs aus PVC und Weichmacher aufgebracht wird, die mindestens ein Harz enthält, das in Wasser ein Gel bildet, daß danach eine Wärmebehandlung zur Filmbildung oder Trocknung bei einer Temperatur ausgefuhrt wird, die hoch genug ist, damit gleichzeitig ein irreversibler Prozeß zur Vorgelierung des Überzugs abläuft und die Schrumpfung des Gels durch Desorption des Lösungsmittels des Sorptionsmittels bzw. durch Verdampfung des Wassers erfolgt, so daß die Risse erzeugt werden; und daß danach eventuell die herkömmlichen Arbeitsgänge zur Fertigbearbeitung ausgefuhrt werden.

2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß die Unterlage aus einer herkömmlichen Unterlage besteht, die eventuell mindestens eine Beschichtung mit einem synthetischen Material und/oder mindestens eine Bedruckung aufweist.

3. Verfahren gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Plastisol-Überzugsgemisch, das die Sorptionsmittel/Lösungsmittel-Kombination oder die wässerige Dispersion aus trockenem PVC und einem Harz, das in Wasser ein Gel bildet, lokal aufgebracht wird.

4. Verfahren gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das überzugsgemisch 0,5 bis 15 Gewichtsprozent, vorzugsweise 2 bis 13 Gewichtsprozent eines Sorptionsmittels enthält.

5. Verfahren gemaß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Sorptionsmittel ein Kieselsäureanhydrid oder ein Silikat ist mit einer spezifischen Oberfläche gemäß BET zwischen 250 und 700 m²/g, vorzugsweise zwischen 300 und 400 m²/g.

6. Verfahren gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das für die besagte Kombination verwendete Lösungsmittel bei der Bildungstemperatur des Überzugsfilms einen sehr hohen Dampfdruck aufweist.

7. Verfahren gemäß einen der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Überzugsgemisch 15 bis 35 Gewichtsprozent, vorzugsweise 20 bis 30 Gewichtsprozent Lösungsmittel enthält.

8. Verfahren gemaß einem der vorhergehenden Anspruche, dadurch gekennzeichnet, daß die Wärmebehandlung zur Bildung des Films in einem Durchlauf, während 1 Minute bis 2 Minuten 30 Sekunden, bei einer Temperatur von 110 bis 160°C besteht.

9. Verfahren gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daB das Harz, das bei Anwesenheit von Wasser ein Gel bildet, ein Zelluloseharz ist.

10. Verfahren gemäß einem der Ansprüche 1, 2 oder 9, dadurch gekennzeichnet, daß die Dispersion ein Solvatationsmittel enthält.

11. Verfahren gemäß einem der Ansprüche 1, 2, 9 oder 10, dadurch gekennzeichnet, daB die Additive, die zur Stabilisierung der wässerigen Dispersion erforderlich sind, aus einem Gemisch von grenzflächenaktiven und schaumverhütenden Mitteln besteht.

12. Verfahren gemäß einem der Ansprüche 1, 2 oder 9 bis 11, dadurch gekennzeichnet, das die Wärmebehandlung zur Trocknung in einem Durchlauf bei einer Temperatur von 180 bis 210°C besteht.

13. Verfahren gemäß einen der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß nach der Bildung der Risse eine zweite Wärmebehandlung durchgefuhrt wird, um die Risse zu erweitern.

14. Verfahren gemäß Anspruch 13, dadurch gekennzeichnet, daß die besagte zweite Wärmebehandlung in einem Durchlauf, während 1 Minute bis 2 Minuten 30 Sekunden, bei einer Temperatur von ungefähr 200° C besteht.

15. Verfahren genäß einen der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß mindestens ein Überzug mit dem Rakel auf das Produkt aufgebracht wird, um die Risse auszufüllen, wie beispielsweise ein Gemisch, das leitenden RuB enthält, oder eine aufschaumbare Paste und/oder eine Bedruckung gemäß einem an sich bekannten Verfahren, oder eine VerschleiB-Deckschicht.

16. Verfahren gemäß einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, das während 1 Minute bis 2 Minuten 30 Sekunden bei einer Temperatur von ungefähr 190°C eine abschlieBende Einbrennung durchgefuhrt wird.

17. Boden- oder Wandbeschichtung mit Craquelé-Effekt, hergestellt gemäß irgendeinem der vorhergehenden Verfahren.

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