FR2675178A1 - Plastic for the production of sheets (slabs) or of widths of coverings for floors or for walls, and covering material obtained - Google Patents

Abstract

The plastic according to the invention is obtained based on polyvinyl chloride (PVC) combined with one or more plasticisers; it also includes at least one complementary thermoplastic resin which is directly compatible with PVC and its plasticisers and which is present in amounts ranging from 5 to 95 % of the total weight of resin. This or these complementary thermoplastic resins may consist of a modified polyolefin copolymer which includes a polar group compatible with PVC and its plasticisers and/or of a thermoplastic elastomer of the thermoplastic-rubber type or thermoplastic-polyurethane type. In combination with complementary additives, the formulations obtained enable plastics to be obtained in the form of monolayer or multilayer sheets or widths.

Description

 The present invention relates to the field of plastic products intended for floor or wall coverings; it relates more particularly to a plastic material for producing tiles or covering strips, based on polyvinyl chloride (PV-), conventionally associated with plasticizers and with a certain number of complementary additives. The invention also relates to the material in the form of a slab or strip, monolayer or multilayer, consisting of at least one layer of such a plastic material.

 Plastic floor covering materials are made available to users, individuals or laying technicians, in the form of slabs, plates or strips, in rolls. These materials are obtained from plastic formulations by the use of conventional techniques, of the coating, calendering, extrusion type, or even by a combination of calendering and extrusion techniques. They can be in a monolayer form, possibly associated with a support of the mat glass type; most often, they are of the multilayer type obtained by assembling several superimposed plastic sheets, generally of a different nature and composition, depending on the desired characteristics of rigidity, resistance, aesthetics or the like.

 An example of a multilayer plastic tile is described in document FR-A-2 557 905. In the plastic formulations used to obtain the different superposed layer (s), all of the resin present consists of polyvinyl chloride (PVC); PVC is associated with plasticizers and a set of additives of the thermal stabilizer, light stabilizer, dye, filler, etc. type.

 Although coating materials of this type are easy to work with, they are not entirely satisfactory in terms of the characteristics of resistance, "hand and dimensional stability (flexibility, sealant, etc.).

 In addition, their high PVC content poses problems of producing harmful gas in the event of a fire.

 Another drawback lies in the fact that in order to impart correct structural qualities to PVC, it is essential to combine it with one or more plasticizers, in more or less quantity. However, these plasticizers reduce the dimensional stability; they migrate to the surface and cause the product to become dirty. Very combustible, they force fireproofing strongly.

 These materials, in connection with their production process, do not generally allow obtaining solid colors of quality. The chromatic rise of the dyes used in this medium is not done under the best conditions, on the other hand, certain plasticizers bring about a background color themselves and there are often shading problems as well as color variations over time .

 The object of the invention is to provide a plastic material based on PVC capable of being used by conventional techniques, in particular extrusion and calendering, and making it possible to overcome the aforementioned drawbacks. The plastic products obtained have, among other things, excellent dimensional stability and a perfect solid color which allows free laying, especially in the case of products in the form of thick slabs. The material also has great homogeneity between the layers and it is possible to produce an unlimited palette of solid colors, without shading, with excellent reproducibility.

 According to the invention, the plastic material for producing slabs or strips of floor or wall coverings is based on PVC associated with plasticizers.

Its formulation comprises, in association with PVC, at least one additional thermoplastic resin, directly compatible with PVC and its plasticizers and which is found in proportions ranging from 5 to 95% of the total weight of resin.

At least part of the additional resin is preferably constituted by a modified polyolefin copolymer, comprising a polar group compatible with PVC and its plasticizers. Thanks to this copolymer, it is also possible to incorporate into the formulation an unmodified polyolefin such as polyethylene, polypropylene or polybutethylene; this unmodified polyolefin, alone, is not compatible with the
PVC; it makes it possible to stiffen the product to better balance it for its solid color and to modify the resistivity of the assembly. The amount of unmodified polyolefin in the formulation depends on the nature (rate and nature of grafting) and on the amount of the polyolefin copolymer.

 A thermoplastic elastomer of the thermoplastic rubber type and / or of the thermoplastic polyurethane can also be used, alone or in combination with the polyolefin copolymer (s).

The resin fraction of the plastic formulation can be established as follows, (in% of the total weight of resin) - PVC: 5 to 95%, preferably 5 to 35% or 65 to 95% - a modified polyolefin copolymer: 5 to 95% and preferably 5 to 35% or 65 to 95% - a thermoplastic elastomer: 0 to 40% and preferably 0 to 25% - an unmodified polyolefin: 0 to 15%, preferably 0 to 8%
This plastic material, associated with a plasticizer and a whole set of conventional additives, allows, by calendering or preferably extrusion or extrusion-calendering techniques, to obtain layers of plastic material in strips or cut in the form of slabs and intended for covering floors or walls.These materials can be monolayers or multilayers, consisting of a plurality of identical layers or of a different nature superimposed.

 The invention also relates to the plastic material consisting of at least one layer of plastic material obtained according to the formulations described above.

 According to a preferred embodiment, the plastic material consists of a superposition of at least two layers of plastic material; it includes a means ensuring dimensional stability, either in the form of a glass mat embedded in one of the layers or arranged between the two layers, or in the form of fibers embedded in one of the layers.

 According to another characteristic of the invention, and in order to provide a constant quality coloration, the surface layer contains titanium oxide at a rate of 1 to 4% of the total weight of resin and the second layer is colored white; thus ensuring, even by transparency, a background of identical color.

This second layer is preferably obtained from plastic material the formulation of which comprises - PVC: 60 to 90% of the total weight of resin - a modified polyolefin copolymer: 10 to 40% - an unmodified polyolefin: O to 10%
According to another characteristic, this second layer comprises an amount of filler material of the calcium carbonate type corresponding to at least one and a half times the total amount of resin. This amount is preferably between 1.5 and 5 times the total amount of resin. The plastic material can also include a third plastic layer, placed directly under the second. This third layer is preferably obtained from at least 50% plastic material according to the invention, combined with recycling products of a chemical nature and in the proportions of the preceding plastics; it can be in compact form or in the form of foam.

 In the case where it is in compact form, it is possible to provide a fourth layer whose nature and composition correspond substantially to the second, as well as a fifth reverse layer of nature and composition corresponding to the third.

This fifth and last layer can be in compact form or in the form of foam.

 Another object of the invention is to propose a plastic material capable, in the same layer, of comprising a plurality of plastic elements of different nature and / or composition and / or color. For the surface layer, one can for example consider the presence of decorations ranging from the simplest to the most complex; always for this surface layer or possibly in depth, this inclusion system can also have significant advantages in certain fields of application, in cases where it is desired to provide an additional element having a function specific to its structure.

 For this purpose, at least one of the layers of the plastic material consists, in its plane, of an assembly of at least two plastic elements obtained by cutting.

These elements are juxtaposed to reconstitute the general shape of the material and they are placed between two mold-forming plates at the level of which heat is supplied so as to obtain a fusion of the materials. This fusion allows the thermoplastic elements to bond together, on edge; it possibly also makes the connection with the lower support layer.

 But the invention will be further illustrated, without being in any way limited by the following description of particular embodiments, given by way of examples and shown in the accompanying drawings and in which - Figure 1 is a sectional view of a slab according to the invention intended for coating a floor - Figure 2 shows an assembly of juxtaposed elements constituting one of the flat plastic layers to achieve in particular a decorative effect on the surface.

The plastic according to the invention is obtained from a resin mixture based on polyvinyl chloride (PVC). The types of PVC known as suspension or mass are preferably usable; according to their nature, they are associated with specific plasticizers as well as with additives which are a function of the final product which it is desired to obtain. These additives can consist of stabilizers, absorbers
UV, flame retardant, charges ...

 The mixture of these constituents, in the form of dry powder and liquids, is placed in a rapid mixer to obtain a pregelling. The necessary dyes are incorporated depending on the end product that is desired.

 After cooling, the additional resin or resins are added, in the form of granules or powder, in an amount between 5 and 95% of the total weight of resin.

These additional resins are chosen either from copolymers of modified polyolefin comprising a polar group compatible with PVC and its constituents, or from thermoplastic elastomers of the thermoplastic rubber or thermoplastic polyurethane type
Preferably, the formulation always comprises a modified polyolefin copolymer. In addition to providing its own structure, the presence of this copolymer makes it possible to act as compatibilizer for PVC and an unmodified polyolefin; the latter constituent can therefore be added to the formulation.

Preferred blends of thermoplastic resin are shown in Table I
TABLE I - Polyvinyl chloride (PVC): between 5 and 35% or 65 and 95% by total weight of resin - modified polyolefin copolymer: between 5 and 35% or 65 and 95% - thermoplastic elastomer: O at 25% - unmodified polyolefin: 0 to 8%
The modifiers of the polyolefin copolymer currently available on the market are: methyl acetate, methyl acrylate and acrylic acid; their level, in the final molecule, varies from 6 to 40%. This rate is chosen according to the desired end product; it makes it possible in particular to vary the melt index of the copolymer and it will be chosen according to its influence on the mixture at the level of the processability and the final behavior.

 The modified polyolefin copolymers are therefore chosen from copolymers of ethylene and vinyl acetate (EVA), copolymers of ethylene and methyl acrylate (EMA), copolymers of ethylene and acrylic acid ( EAA) and the other copolymers of the same type obtained in the families of polypropylene and polybutethylene. They can also be chosen from copolymers of acrylic acid partially neutralized by metal ions and known by the name of ionomers.

In the resin formulation, such complementary copolymers take the place of PVC; they help fix the plasticizer by preventing its migration and improve the internal cohesion of the formulation by creating polar bonds and so-called NPV forces
DER WAALS. These products further improve the wear resistance and soilability properties. The mechanical inertia is improved as is the regularity of the coloring. These products further reduce the transformation temperature of PVC; its degradation is avoided, and the risk of toxicity in the event of fire is reduced.

 In addition, as seen above, these copolymers play the role of compatibilizer making it possible to add unmodified polyolefins to the formulation.

 In the case where the level of polymer of the polyolefin type is high, to avoid the production of a product which is too stiff and too slippery, it is necessary to correct the formulation by adding a modifier of the thermoplastic elastomer type such as thermoplastic rubber. , thermoplastic polyurethane or other fillers which, being found on the surface, have known non-slip properties.

 The thermoplastic rubber can be chosen from nitrile rubbers, EPDM (ethylene-propylene diene monomer), SBS (styrene butadiene-styrene) or even natural rubbers.

These elastomers also replace part of the
PVC and therefore its plasticizer. The processability of PVC is improved; better smoothness and greater homogeneity are obtained. The product is extruded or calendered more easily and it is possible to reduce, or even remove certain additives to aid extrusion or calendering. The presence of these products also improves in particular the resistance to wear and puncture.

 The use of complementary resins makes it possible to limit the content of plasticizers in the formulation and to better control the coloring of the product. This limitation of the influence of the plasticizer on the dye, associated with the low melting point of the modified polyolefins makes it possible to ensure a rapid chromatic rise and good dispersion of the color in the plastic.

 The pregelified primary mixture, generally called "dry blend" (PVC base, plasticizers, additives and dyes) ensures a first color increase, completed by the second hot mixture, made with complementary resins.

To obtain the best results, the coloring matters are chosen in the pigments and dyes resulting from the organic synthesis, in particular the series of chromophtales
The plastic formulation thus obtained, which is in the form of powder or granules, can be implemented on conventional treatment lines of the extrusion or calendering type or on a combination of these two techniques. In extrusion, one can for example use a single screw, a double screw or a double-stage screw to exit at the end of the die a plate whose thickness can vary between 0.05 mm and 5 mm. Calendering reasonably limits the thickness to 0.8 mm.

 The flat sheet of thermoplastic material obtained is conventionally treated to obtain a monolayer or multilayer floor covering product, in the form of strips or cut into the form of tiles. Multilayer products can be formed directly in line, either by bringing in rolls of semi-finished product, or by using successive dies: they can also be produced in a separate apparatus with heating and assembly by cylinder of the various layers under pressure.

 Rather than being assembled continuously, the different layers can be precut to size and assembled in molds using heat sources of the high frequency type or conventional thermal means.

 A multilayer product of this type is shown in cross section in Figure 1.

 The surface layer 1, or wear layer, may have to meet the standards in force, a thickness of the order of 0.15 to 1 mm (it is of course possible to leave this thick frame). It can for example be obtained from one of the three formulations in Table II (the units indicated are by weight of material).

TABLE II
Material (1) (2) (3)
PVC 100 100 100
Plasticizers (DIUP and DBP type 35 35 30
or others ..)
EVA 30% acetate 6 12 150
EVA 9% acetate 10 6 150
Stabilizers and additives 5 5 12
Type nitrile rubber 5
UV absorber 0.2 0.2 0.8
Titanium oxide 2
Dyes 3 -
Flame retardant system 7
The titanium oxide present in formulation (1) makes it possible to produce a masking base for the dye; formulations (2) and (3) allow a crystal film to be obtained.

The second layer 2, placed directly under the wear layer preferably does not contain thermoplastic rubber. Its formulation may include - PVC: 60 to 90% of the total weight of resin - a modified polyolefin copolymer: 10 to 40% - an unmodified polyolefin: O to 10%
An example of a usable formulation is defined in Table III
TABLE III
Material Weight
PVC 100
EVA 33% acetate 20
EVA 6.5% acetate 15
Plasticizers 70
Titanium oxide 4
Stabilizers 8
Flame retardant system 25
Fillers (Ca carbonate) 475
The copolymer with a high acetate content makes it possible to improve the compatibility and the fluidity when hot in the medium, in particular because of the large amount of calcium carbonate; that with a low acetate content is present to cause a stiffening effect.

This stiffening effect can be further increased by adding up to 5 parts of polyethylene (this polyethylene must then be premixed hot with the copolymers).

 The assembly makes it possible to further decrease the melting point. This characteristic contributes to the good association of the other layers and improves the flooding of the integrated glass mat 3.

This characteristic also plays a role of distributor of the integrated filler material (carbonate of
Ca, from Mg ...). This filler material participates in the plumbing of the material; it limits the proportion of plastic material and consequently reduces the cost price per kilo.

 The thickness of this second layer is preferably between 0.1 and 0.3 mm; it is preferably white in color so as to participate in the regularity of coloring of the surface layer 1. The combination of thermoplastic resins according to the invention allows, in association with the white background of the second layer (2), insert less titanium oxide into the wear layer to obtain satisfactory coverage, compared to the plastics of the prior art.

This characteristic makes it possible to limit the contribution of dyes to obtain a determined coloring; we are helping to reduce the nuance problems.

 The third layer 4 can be obtained from a formulation similar to that of the first and second layers. Preferably, it is obtained from at least 50% plastic material according to the invention, combined with a supplement consisting of recycling products from layers 1 and 2 above.

 This layer 4 is intended to bring thickness (1 to 2.5 mm); it brings weight, participates in the plumbing and the holding. To improve sound insulation, it can be in the form of foam; in compact form, it withstands high loads very well.

 The fourth layer 5 has a structure and a composition analogous to the second layer 3. It also comprises a glass mat 6 embedded for improving the dimensional stability. The presence of the two glass mats 3 and 6 achieves an excellent balancing of the material and also improves its lead strength. I1 allows in particular the free laying of slabs obtained according to this structure.

 The reverse layer 7 has a structure and composition similar to the third layer 4. It can be in compact form or in the form of foam.

An example of a possible formulation is indicated in the following table IV
TABLE IV
PVC 100
Plasticizer 80
EVA 33% 25
Stabilizer 8
Black pigment 2
Flame retardant system 30
Recycled layer 25
Calcium carbonate 500
To obtain a foam, 10 parts of porogen of the azo-bisdicarbonamide type will be provided to this formulation.

 The plastic material thus produced can be cut in the form of tiles of 50 x 50 cm. The thickness of this material can be close to 5 mm. The different layers 1, 2, 4, 5 and 7 are assembled to each other in a conventional manner, by direct lamination or by assembly individually.

 Of course, provision may be made to use formulations of thermoplastic material defined above in order to obtain multilayer coating products having a number of layers and a structure different from that described in the particular embodiment of FIG. 1; one can also provide the possibility of producing monolayer coatings, for example associated with a support of the glass mat type.

 The different thermoplastic layers described in connection with FIG. 1 can be combined as desired with one another, depending on the structure of the desired final material.

 In association with the structural characteristics defined above, the invention also proposes an original plastic material of which at least one of the layers consists, in its plane, of an assembly of at least two juxtaposed plastic elements. These elements can be of a different nature or color; their particular arrangement allows the realization of the most diverse aesthetic and / or technical effects.

 Figure 2 shows a possible embodiment

Claims (13)

of this type of product, in particular for producing a surface decoration. This exemplary embodiment is described in conjunction with a whole set of technical and computer means which it is of course possible to adapt and replace with equivalent means, as required.  The production of the surface layer 9 initially consists of entering the decoration, the inscription or the contours of the tracing in the memory of a computer, in conjunction with suitable software. This operation can advantageously be carried out either by a scanner reading, or by means of a plotting table.  The computer is suitable for controlling a cutting tool in the form of a blade, water jet, laser, plasma, cutter or other ... depending on the thickness and resistance of the material. The software can advantageously take into account the thickness of the cutting line (depending on the tool used) to avoid, if desired, the presence of play between the different elements.  The cutting of the different elements 10, 11, 12 is carried out in plates of different types and / or colors depending on the desired effect. Their juxtaposition reconstructs the general shape of the material. The elements 10, 11, 12 edge to edge are arranged between two mold-forming plates, with or without an edge. The plates provide flat pressure on the reconstituted layer 9; this layer is optionally placed in the mold on a lower support layer 13, of a nature compatible with the elements 10, 11, 12 juxtaposed. This layer 13 is preferably of the nature of those which are described elsewhere.  The heat supply can for example be carried out by techniques of the high frequency type, to arrive at a temperature of the order of 1500C. The intensity used can be 2 Amps applied for 20 seconds obtained from an initial machine power of 50 Kwatt.  The edge-to-edge connection of the various elements 10, 11, 12, juxtaposed and of said elements, optionally with the support layer 13, is produced by heat input to achieve a fusion of the thermoplastic material. The temperature and the application time are adapted so as to obtain a fusion just sufficient to achieve a good bond without color migration or deformation of the lines.  The molds used can be of the epoxy resin or crosslinked silicone type; the pressures applied on the  2 layers 9 and 13 are greater than 2 kg per cm  Conventional thermal means or ultrasonic techniques can also be used to generate the supply of heat. The nature of the molds used will depend on the means chosen.  The thermoplastic nature of the products requires their cold removal from the molds; for this purpose, the latter are preferably equipped with cooling systems.  As shown in Figure 2, the various elements 10, 11, 12, juxtaposed are joined to each other by edge to edge fusion; they are assembled on the support layer 13 also by fusion. The bilayer plate as shown can be used as it is; it is also possible to associate it with different lower layers of a suitable nature to obtain a material for example of the type shown in FIG. 1; other layers, for example transparent, can also be superimposed on it to allow the realization of depth effects.  This technique can be used to make any type of decor, on plastic coating materials. The thermoplastic formulations which are the subject of the invention are very suitable for achieving satisfactory results in terms of the connection of the different elements with a view to reconstituting a flat surface of constant thickness.  The reference signs inserted after the technical characteristics mentioned in the claims are intended only to facilitate the understanding of the latter and in no way limit their scope.  1.- Plastic material for producing slabs or strips of floor or wall coverings, containing polyvinyl chloride normally associated with plasticizers, characterized in that its formulation comprises, in combination with polyvinyl chloride, at least a complementary thermoplastic resin, directly compatible with polyvinyl chloride and its plasticizers, present in proportions ranging from 5 to 95% of the total weight of resin.  - CLAIMS  2. Plastic material according to claim 1, characterized in that the or one of the complementary thermoplastic resins is a modified polyolefin copolymer, comprising a polar group compatible with PVC and its plasticizers.  3. Plastic material according to claim 2, characterized in that its formulation comprises an unmodified polyolefin of the polyethylene, polypropylene or polybutethylene type.  4. Plastic material according to any one of claims 1 to 3, characterized in that the or one of the complementary thermoplastic resins is a thermoplastic elastomer.  5.- Plastic material according to any one of claims 1 to 4, characterized in that its formulation comprises - PVC: 5 to 95% by total weight of resin, - a modified polyolefin copolymer: 5 to 95% - a thermoplastic elastomer: 0 to 40% - an unmodified polyolefin: O to 15%.  6. Plastic material according to claim 5, characterized in that its formulation comprises - PVC: 65 to 95% or 5 to 35% by total weight of resin - a modified polyolefin copolymer: 5 to 35% or 65 to 95 % - a thermoplastic elastomer: 0 to 25% - an unmodified polyolefin: O to 8%.  7. Plastic material in the form of a slab or strip for covering floors or walls, consisting of at least one layer of plastic material according to any one of claims 1 to 6.  8.- plastic material according to claim 7, characterized in that it consists of a superposition of at least two layers (1, 2) of plastic material according to any one of claims 1 to 7, which material comprises means ensuring dimensional stability, either in the form of a glass mat embedded in one of the layers (1, 2) or arranged between the two layers (1, 2), or in the form of fibers embedded in one of the layers .  9. Plastic material according to claim 8, characterized in that the surface layer (1) contains titanium oxide at a rate of 1 to 4% of the total weight of resin and in that the second layer (2) is white in color.  10.- Plastic material according to any one of claims 8 or 9, characterized in that the second layer (2) is obtained from plastic material whose formulation comprises - PVC: 60 to 90% of the total weight of resin - a modified polyolefin copolymer: 10 to 40% - an unmodified polyolefin: 0 to 10% - filler material (calcium carbonate): 1.5 to 5 times the total amount of resin.  11.- plastic material according to any one of claims 8 to 10, characterized in that it comprises a third layer (4) disposed under the second (2), which third layer (4) is obtained from at at least 50% of plastic material according to any one of claims 1 to 6, the remainder consisting of recycling products of a chemical nature and in the proportions of the preceding plastics.  12.- plastic material according to claim 11, characterized in that it comprises a fourth layer (5) of nature and composition corresponding to the second (2) and a fifth layer (7) of reverse, of nature and of composition corresponding to the third (4).  13.- plastic material according to any one of claims 7 to 12, characterized in that at least one of the layers consists, in its plane, of an assembly of at least two plastic elements (10, 11) obtained by cutting, said elements (10, 11) being juxtaposed to reconstitute the general shape of the material and placed between two mold-forming plates at the level of which a temperature contribution is made to obtain a fusion allowing the elements (10, 11) to be bonded between them, on edge and possibly with a lower support layer (13)