EP0126314A1 - Process for locally matting synthetic coatings, and products obtained - Google Patents

Abstract

The method comprises depositing on a foamable or non-foamable support (2), in a first zone (3), a coating or impression containing at least one radiative polymerization initiator and, in a second zone (4) which may possibly comprise partially the first zone, of a coating based on crosslinkable monomer, a pregelling and at least locally a graining; polymerization of the coating of the first zone by initiation under radiation in order to fix its appearance and then a gelation which, causing the fluidization of the varnish, causes the disappearance of the grainy appearance in the non-crosslinked zone, and possibly an expansion. Application to the production of wall and floor coverings.

Description

The present invention relates to a method for locally mattering a synthetic covering surface, more particularly a PVC-based floor or wall covering and the products obtained.

The majority of plastic coatings do not have, on their surface, a sufficient difference in gloss-dullness to give certain areas of the surface a particular appearance. Said zones can for example be a pattern applied by printing on a coating or an imitation of a joint, in the case of a coating imitating a ceramic tile.

In document US-A-4 273 819, the joint between the tiles is matified with an imitation of ceramic tiles by adding a vinyl monomer and a thermal initiator throughout the surface layer and by graining from this surface. The prints containing a catalyst lowering the decomposition temperature of the thermal initiator keep the mat (grainy) appearance, while the other areas lose their graining during gelation.

This process has the drawback of being strongly linked to the graining temperature. A slight overshoot of the temperature may initiate crosslinking at the level of the entire surface of the product, and keep a matt appearance to the entire product. Too low a temperature, on the other hand, does not lead to a matt appearance, even at the joints. Given the kinetic aspect of the decomposition of the initiator, a too long graining time, but at the right temperature, risks presenting the same problem (total graining).

Another technique for obtaining a matt / shiny effect is described in FR-A _- 2,531.009.

The present invention relates to an improved method of local mattification of a coating surface synthetic which is not linked to the graining or gelling temperature and which is independent of the graining time.

According to the present invention, the object is achieved by providing a process in which a coating or a print containing at least one "radiative" polymerization initiator and, in a second zone which optionally at least partially comprises the first zone, at least one coating based on crosslinkable monomer; pre-gelation is carried out; graining is carried out at least locally; the coating of the first zone is polymerized by initiation under radiation in order to fix its appearance and then a gelling is carried out which, causing the thinning of the varnish, causes the disappearance of the grainy appearance in the non-crosslinked zone, and possibly an expansion .

By "radiative initiator" is meant any suitable initiator which is decomposed or modified by energetic radiation, for example by UV rays, to form free radicals or ions necessary for propagation of chains in a polymerization reaction.

According to a preferred embodiment of the present invention, an ink or a cut containing a UV polymerization initiator is deposited on a foamable support or not, at least in a first zone.

In this way, it is therefore possible to initiate locally, that is to say at the places where said UV initiator is deposited, the polymerization after graining to stiffen the surface of said first zone and maintain, during the following operations, the matt appearance. of this surface.

The method of the invention also has the advantage of allowing graining of the entire surface of the coating, without having to provide a specific grain roller controlled in accordance with the pattern or the decoration of the coating, since the area which is not polymerized after graining will be thinned during treatment subsequent gelling and will be smoothed by surface tension.

• diméthacrylate d'éthylèneglycol,
• diacrylate d'éthylèneglycol,
• diméthacrylate de diéthylèneglycol,
• diacrylate de diéthylèneglycol,
• diméthacrylate de triéthylèneglycol,
• diacrylate de triéthylèneglycol,
• diméthacrylate de tétraéthylèneglycol,
• diacrylate de tétraéthylèneglycol,
• diméthacrylate de polyéthylèneglycol,
• diacrylate de polyéthylèneglycol,
• diméthacrylate de 1,3-butylèneglycol,
• diméthacrylate de 1,4-butylèneglycol,
• diacrylate de 1,3-butylèneglycol,
• diacrylate de 1,4-butylèneglycol,
• diacrylate de 1,4-butanediol,
• diméthacrylate de 1,6-hexanediol,
• diacrylate de 1,6-hexanediol,
• diacrylate de néopentylglycol,
• diméthacrylate de néopentylglycol,
• diméthacrylate (éthoxylé) de bisphénol A,
• divinylbenzène,
• divinyltoluène,
• triméthacrylate de triméthylolpropane,
• triacrylate de triméthylolpropane,
• triacrylate de pentaérythritol,
• triméthacrylate de glycéryle,
• tétracrylate de pentaérythritol,
• tétraméthacrylate de pentaérythritol,
• diméthacrylate de 1,4-butanediol.

By way of examples of monomers suitable for the practice of the invention, mention may be made of the following compounds (non-limiting list):

• ethylene glycol dimethacrylate,
• ethylene glycol diacrylate,
• diethylene glycol dimethacrylate,
• diethylene glycol diacrylate,
• triethylene glycol dimethacrylate,
• triethylene glycol diacrylate,
• tetraethylene glycol dimethacrylate,
• tetraethylene glycol diacrylate,
• polyethylene glycol dimethacrylate,
• polyethylene glycol diacrylate,
• 1,3-butylene glycol dimethacrylate,
• 1,4-butylene glycol dimethacrylate,
• 1,3-butylene glycol diacrylate,
• 1,4-butylene glycol diacrylate,
• 1,4-butanediol diacrylate,
• 1,6-hexanediol dimethacrylate,
• 1,6-hexanediol diacrylate,
• neopentylglycol diacrylate,
• neopentylglycol dimethacrylate,
• bisphenol A (ethoxylated) dimethacrylate,
• divinylbenzene,
• divinyltoluene,
• trimethylolpropane trimethacrylate,
• trimethylolpropane triacrylate,
• pentaerythritol triacrylate,
• glyceryl trimethacrylate,
• pentaerythritol tetracrylate,
• pentaerythritol tetramethacrylate,
• 1,4-butanediol dimethacrylate.

To these compounds which have at least two propagation sites, a certain amount of compounds can be added. monomers with a propagation site.

Particularly preferred compounds are 1,4-butylene glycol dimethacrylate and trimethylolpropane trimethacrylate.

In the case where the matt effect is desired at the joints of a covering imitating ceramic tiles, the ink containing the radiative initiator may also contain an expansion inhibitor.

In the case where the matt effect is desired at the location of a pattern applied to a foamed area, the ink or the cut obviously does not contain an expansion inhibitor.

In particular, conventional expansion inhibitors can be used, preferably trimellitic anhydride (TMA).

As a UV polymerization initiator, the Merck DAROCUR®1173 or DAROCUR61116 products are used as reference at a rate of 1 to 50%, preferably of the order of 20% by weight, of the ink or of the cut.

• benzophénone,
• 2-chloro-thioxanthone,
• 2-méthyl-thioxanthone,
• 2-isopropyl-thioxanthone,
• benzoïne,
• 4,4'-diméthaxybenzaïne,
• benzoïne-éthyl-éther,
• benzoïne-isapropyl-éther,
• benzyldiméthylcétal,
• 1,1,1-trichloro-acétophénone,
• 1-phényl-1,2-propanediane-2-(éthoxycarbanyl)-oxime,
• diéthoxyacétophénone,
• dibenzosubérone,
• Darocur® 1398
• Darocur 1174
• Darocur 1020.

Other compounds such as the following are also suitable (nonlimiting list)

• benzophenone,
• 2-chloro-thioxanthone,
• 2-methyl-thioxanthone,
• 2-isopropyl-thioxanthone,
• benzoin,
• 4,4'-dimethaxybenzain,
• benzoin-ethyl ether,
• benzoin-isapropyl-ether,
• benzyldimethylketal,
• 1,1,1-trichloroacetophenone,
• 1-phenyl-1,2-propanediane-2- (ethoxycarbanyl) -oxime,
• diethoxyacetophenone,
• dibenzosuberone,
• Darocur® 1398
• Darocur 1174
• Darocur 1020.

The use of at least two different radiative initiators, in the same zone or different zones and different layers, also falls within the scope of the invention.

The coating containing the crosslinkable monomer contains 1 to 50%, preferably approximately 11% by weight, of monomer comprising at least two chain propagation sites, optionally in mixture with monomers having a chain propagation site.

• - la figure 1 représente le support utilisé pour le procédé de l'invention,
• - la figure 2 représente la première étape du procédé,
• - la figure 3 représente le revêtement après l'enduction de la deuxième zone,
• - la figure 4 représente l'étape de grainage,
• - la figure 5 représente l'initiation radiative de polymérisation, et
• - la figure 6 représente le produit fini.

The invention will be described in more detail in support of the appended figures in which:

• FIG. 1 represents the support used for the method of the invention,
• FIG. 2 represents the first step of the process,
• FIG. 3 represents the coating after the coating of the second zone,
• FIG. 4 represents the graining step,
• FIG. 5 represents the radiative initiation of polymerization, and
• - Figure 6 shows the finished product.

It should be noted that the description using particularly preferred embodiments of the invention is only given by way of example and that it in no way aims to limit the scope of the present invention. The mattification process applied to relief products obtained by screen printing also falls under the invention.

According to a variant of the invention, it is also possible to complete the smoothing by surface tension occurring during gelation, either by a mechanical smoothing treatment by roller, or by a graining, preferably light, hot.

It is also a matter of the invention to provide exposure to infrared radiation at the end of treatment, for example at the outlet of an expansion oven in order to assist the smoothing operation of the surface of the product.

According to an additional embodiment, in order to facilitate the production operations of the covering of floors or walls and to be able to initiate the crosslinking steps differently, it is provided that said second zone can be initiated directly or by means of a radiative energy transfer agent, so that each of the initiations can be triggered by its own physicochemical effect. In this way, it becomes possible to separate the polymerization initiations in the zones in question as a function of the initiators and / or of the physicochemical initiation effects used so that the polymerization initiation energy supplied by the radiative route in a first zone cannot initiate the polymerization of the other zone.

This separation of effects therefore makes it possible to polymerize an area and to fix its appearance then to polymerize the second area without altering the appearance of the first area.

Advantageously, the initiation of polymerization of the second zone by direct radiative route or by means of an energy transfer agent can be carried out by X-ray radiation, by an electron beam or by γ radiation.

In order for the energy transfer agent to be able to fully exert its effect, it must act on a product for which sufficient mobility of the crosslinkable monomer is ensured.

This condition is best achieved from an industrial hot point of view by submitting the product in an oven, preferably the oven in which gelation and / or possible expansion is carried out in a conventional manner or immediately upon leaving this oven when the product is still at a sufficient temperature.

In this way, it is possible to cause the polymerization in the first zone by the techniques described above and then the polymerization in the second zone by the appropriate physicochemical means, and this without significant modifications of the production lines. existing flooring.

The monomers used, the application techniques located in the different zones and, in general, the whole technological process is identical, mutatis mutandis to what has been described above.

The technique to be used to carry out initiation in said second zone by radiative means using as trimethylolpropane trimethylacrylate can be that described for example by Salmon and Loan J. Appl. Polym. Sci., 16, 671 (1972).

For the practice of techniques involving the use of electron beams, one can in particular use the "ELECTROCURTAIN" ® apparatus manufactured by Ateliers de Charmilles (Energy Sciences International) of Geneva (Switzerland) by applying sufficient energy to penetrate in depth the layer to be crosslinked, for example of the order of 175 KV for doses of 2Mrad.

EXAMPLE 1

Preferably, the support consists of a substrate 1 and a coating at the rate of 500 g / m ² of a foamable plastisol 2. On this coating of foamable plastisol, we deposit (Figure 2), in one or more steps, in a first zone, according to a decoration imitating the design of a tiling joint 3, a conventional ink containing an expansion inhibitor and approximately 20% of a DAROCUR® 1173 or 1116 UV initiator and, according to a decorative pattern any 4, an ink containing a UV initiator It is obvious that the ink can be replaced by a cut, that is to say a solution without dye or pigment, according to the decorative effects which it is desired to obtain. This deposit is advantageously done by a technique of gravure printing or screen printing.

Next, a coating of transparent plastisol, as a wear layer 5, containing an acrylic monomer (ROCRYL 980) or another monomer compatible with the chosen initiator is deposited (FIG. 3) over the entire surface. then a pregelification is carried out at the usual temperature for this kind of operation, that is to say between 100 and 160 degrees.

FIG. 4 represents the graining step by means of a graining cylinder, over the entire surface, at a temperature usually practiced for this operation, that is to say at a temperature above 100 ° C., under a pressure depending on the desired degree of dullness. The pre-gelation and graining steps can be carried out in a single step, using an adequately heated graining cylinder.

Passage under a UV lamp 7 (FIG. 5) makes it possible to crosslink the area containing the U.V. initiator so that the (grained) state of this area is fixed by the crosslinking.

Then, the product obtained is passed, for 1 minute to 2 minutes 30 seconds, in an oven at about 200 ^° C., intended to expand the foamable coating 2 in places which do not contain an expansion inhibitor to be gelled and to fluidize the zone which has not been polymerized during the UV initiation by causing a fluidification which has the effect of smoothing the grained surface, while the grained and crosslinked zone during the UV initiation maintains its grained state (mat ). The product shown in Figure 6 is obtained.

EXAMPLE 2

The procedure is as in Example 1, replacing the PVC with a copolymer of PVC (95%) and polyvinyl acetate (5%), all the other parts remaining equal.

The following composition was used:

The pregelling is advantageously carried out on a cylinder at 130 ° C., this temperature can even be exceeded as a function of the running speed of the product.

It is found that this composition makes it possible to achieve better gelation and better smoothing.

Claims (20)

1. A method for obtaining matt and smooth areas on a synthetic coating, characterized in that at least one coating or impression is deposited on a foamable or non-foamable support, containing at least one radiative initiator of polymerization and, in a second zone which may optionally partially comprise the first zone, at least one coating based on crosslinkable monomer; in that one performs a pre-gelation and at least locally a graining; in that the coating of the first zone is polymerized by initiation under radiation in order to fix its appearance and in that a gelling is then carried out which,. causing
the fluidificatian of the varnish, causes the disappearance of the grainy appearance in the non-crosslinked zone, and possibly an expansion. 2. Method according to claim 1, characterized in that a radiative polymerization initiator is used as a UV polymerization initiator which is applied in said first zone in an ink or a cut. 3. process according to claim 2, characterized in that the substances DAROCUR ®1173 or DAROCUR ® 1116 (from Merck) are used as UV initiator. 4. Method according to any one of the preceding claims, characterized in that at least one of the two zones comprises a coating containing an inhibitor of expansion of the support, more particularly trimellitic anhydride (TMA). 5. Method according to claim 3 or 4, characterized in that an ink is used containing 1 to 50%, preferably 20% by weight, of DAROCUR ®1173. 6. Method according to any one of claims 1 to 5, characterized in that the coating based on crosslinkable monomer contains 2 to 50%, of the order of 11% by weight of monomer comprising at least two propagation sites . 7. Method according to any one of claims 1 to 6, characterized in that a relief is obtained by a plastisol deposition according to a screen printing process. 8. Method according to any one of claims 2 to 7, characterized in that the deposition of ink or cutting is done by a printing technique by gravure printing, by screen printing or by flexography. 9. Method according to any one of claims 1 to 5, characterized in that the pregelling is carried out in a range of 100 to 160 ° C. 10. Method according to any one of claims 1 to 9, characterized in that the graining is carried out at a temperature above 100 ° C, under a pressure depending on the desired degree of dullness. 11. Method according to any one of claims 1 to 10, characterized in that one finally performs an expansion of the foamable support at about 200 C, for 1 minute to 2 minutes 30 seconds. 12. Method according to any one of claims 1 to 11, characterized in that the pre-gelation and graining step is carried out in a single step, by means of a heated graining cylinder. 13. Method according to any one of claims 1 to 12, characterized in that the product is heated on the surface by exposure to infrared radiation, preferably at the outlet of an expansion oven. 14. Method according to any one of claims 1 to 13, characterized in that the smoothing effect due to the surface tension resulting from the fluidization occurring during gelation is completed, either by mechanical treatment with a smooth roller or structured. 15. Method according to any one of claims 1 to 14, characterized in that at least one uses two different radiative initiators in the same area or in different areas and different layers. 16. Method according to any one of claims 1 to 15, characterized in that said second zone is initiated directly or by the intermediary of an energy transfer agent by radiative way, so that each of the initiations can be triggered by a specific physicochemical effect. 17. The method of claim 16, characterized in that the polymerization initiation energy supplied radiatively in a first zone cannot initiate the polymerization of the other zone. 18. The method of claim 16 or 17, characterized in that the initiation of polymerization of the second zone by direct radiative or by means of an energy transfer agent is carried out by X-ray, a beam of electrons or radiation 19. Method according to any one of claims 16 to 18, characterized in that the radiative energy transfer agent acts on the product to be treated in a hot oven which is preferably the oven in which one performs gelling and / or possible expansion or immediately upon leaving this oven when the product is still at a sufficient temperature. 20. Products obtained by the process of any one of claims 1 to 19.

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