EP0520151B2 - Latex-, PVC- and plasticiser-free, foamed floor and wall coverings - Google Patents

Abstract

A process for producing latex-, PVC- and plasticiser-free textile or plastic floor or wall coverings which contain, inter alia, a foamed layer, a powder mixture consisting of 100 parts of a thermoplastic polymer 0-100 parts of fillers 0.5-7 parts of blowing agent 0-30 parts of auxiliaries being scattered in an amount corresponding to the required thickness onto the base layer below the subsequent foamed layer and melted at temperatures of 70-110 DEG C, polished between polishing rolls and foamed at temperatures of 120-200 DEG C. The invention further relates to the novel means and to the coverings produced therewith. <IMAGE>

Description

The present invention relates to the production of latex, PVC and plasticizer-free floor and wall coverings with chemically foamed and optionally structured foam layers.
Textile floor and wall coverings with a back-foamed layer made of a natural or synthetic latex and PVC plastic coverings are used today on a large scale due to their diverse decorative possibilities through simple installation and value for money.

In particular, the ability to equip the rubbers with soft, foamed backs what contributes significantly to the impact sound insulation and improves walking comfort for the others Spread of such materials worried. In addition, the foaming enables generation of Surface structuring either by foaming in appropriate shapes or embossing rollers or by partial chemical activation or inhibition of foam formation. With textile coverings technically only mechanical foaming by injecting air into the latex mass, because chemical foaming requires high temperatures which damage the textile pile.

In order to avoid bumps when laying, floor coverings in particular are commonly used today Continuous webs in a width of up to 4 or 5 m made, both of the material and the Processing techniques extremely limits the possibilities.

Textile floor coverings are either manufactured using the tufting process or from needle felt, the back solidified with a styrene butadiene or other latex mass and then with a mechanical foamed synthetic or natural latex layer coated and fixed by drying. The The textile layer mainly consists of polyamide, polypropylene or polyester fibers, which are not more of the latex layers can be separated so that such composite layers are not recyclable are. From GB-A 2191209 and GB-A 1420624 is also known, the back coating too by sprinkling a powder of a polymer, fillers and possibly blowing agents, which are melted and, if necessary, foamed and thus glue and stabilize the textile fibers. As Polymers are called polyethylene, polyester, polyamides, EVA and their copolymers.

So far, plastic floor coverings are usually made of latex dispersions or PVC plastisols Coating process on a tissue or release paper base and then curing. The plastisols consist of PVC particles, plasticizers, and conventional auxiliaries and fillers, which sinter into a matrix when dried in the warmth. By adding chemical Foam agents can additionally be thermally foamed, whereby by applying an additional structuring of blowing agent activators or deactivators in certain areas can be reached. Of course, it is also possible to apply several layers different properties to vary the properties to a very large extent (see e.g. "Solvic® for plastisols ", company lettering of Deutsche Solvay-Werke GmbH, Solingen).

Although latex and PVC are ideal materials in terms of economy and properties are, however, require the increasingly important ecological aspects - recyclability of products, avoidance of solvents and halogen-containing components - manufacturing processes of coverings that are free of latex, PVC and plasticizers. From economic and For technical reasons, however, it is necessary to use the previous manufacturing widths and, if possible also to maintain the existing manufacturing devices. The flooring should also be made different layers exist, one or more of which are chemically foamed and possibly partially are structured by activating or deactivating the foaming process.

The object of the present invention was therefore to find a method by which latex, PVC and Plasticizer-free plastic floor and wall coverings can be produced, which at least consist of a chemically foamed layer and a carrier layer, if necessary structuring Allow activation or deactivation of the propellants and usual manufacturing widths of 4-5 m allowed to manufacture existing devices. For the production of floor coverings is additional there is at least one non-foamed top layer.

This object is achieved by the features reproduced in the main claim and by the in the characteristics characterized in the subclaims.

It is known from the so-called Furukawa process to produce crosslinked polyethylene foams by using polyethylene, azodicarbonamide as blowing agents and dicumol peroxide as crosslinking agents Using an extruder with a downstream slot die to form a matrix in the form of a film or extruded foam sheet, this extrusion must be carried out at a temperature at which Polyethylene is liquid, but the crosslinking agent has not yet decomposed. Either after one Intermediate storage or by direct introduction of the matrix into a foaming furnace becomes the radical one Decomposition of the peroxide is initiated and the polyethylene crosslinks with simultaneous chemical decomposition of the Blowing agent and foaming of the matrix. This process currently allows foams with density between 30 and 175 kg / m3 and thicknesses between 5 and 15 mm. The width of these foams is however, limited to about 2 m, since wide-slit nozzles of a larger size cannot be produced. A It is not possible to produce conventional floor coverings economically using this method.

It is also known that one can also from ethylene vinyl acetate copolymers (EVA) or mixtures of EVA with polyethylene (PE) moldable foams by using polymers, fillers, activators, Foaming agent and possibly crosslinking agent at temperatures of 90 - 100 ° C, i.e. a temperature where the polymer is already soft or liquid, but the additives remain chemically stable, mixed and the mixture granulated. The granules are then filled into molds by heating foamed and removed from the mold after cooling again. Smaller, even more complicated ones Molded parts can be manufactured well in this way. Examples of this are shoe soles, balls, Seals, mats, masks etc. The production of 4 - 5 m wide continuous webs, such as those used for floor coverings are not necessary using this procedure.

It is also known to plasticizer-free polyurethane foams by mechanical foaming To produce components with air injection, but the foaming cannot chemically hindered and therefore no structure can be created.

It is extremely surprising that the commercially available powder scattering machines are the ones according to the invention Mixtures can be distributed evenly across widths of 4 - 5 m, so that the following Passing through the drying oven creates a homogeneous, evenly thick foam layer. Multilayers can also be produced simply by solidifying and if necessary, leveled layer sprinkles a second powder layer, again dries or gels. A coloring The layer is structured by printing on the color pattern in the meantime an activator or deactivator possible.

The polymers which can be processed according to the invention comprise a large number of thermoplastic products. The most important parameter is the melt index (MFI 190 ° C / 2.16). It was found that at Melting indices below 2.5 and above 40 the too high or too low melt viscosity is not a good one Cell structure of the foam allows more. A melt index of around 10 - 20 seems optimal in this respect To produce results. The crystallite melting point of the polymers should be below the decomposition range of the blowing agent mixture, but not so low that the foam e.g. under strong Sun exposure or weight load begins to flow. Crystallite melting points in one area from 70 - 110 ° seem to be well suited. Very low melting points of the polymer can however, by subsequent crosslinking, for example by adding peroxide or by Treatment with high-energy radiation. Suitable polymers are copolymers from ethylene and vinyl acetate, polyethylene, polypropylene, copolymers with polyvinyl acetate, polymethyl methacrylate, Polyethylene acrylic acid ester copolymers, polyethylene acrylic acid ester, maleic anhydride copolymers and other.

The polymers are made from the commercially available granules to a maximum grain size of 400-600 µm, preferably 10-400 µm, ground and mixed in this form with the other components.

All additives are possible as additives, which are also available in the usual foam mixtures be used. Examples include inorganic fillers such as chalk, silicates, magnesium or aluminum hydroxides, Heavy spar, silica, glass powder, carbon black, titanium dioxide or other color pigments, which at the same time change the translucency of the foam. As organic additives come in particular wood or cork flour or also temperature-resistant plastics such as polyurethanes in question. These are added to the mixture as fine powders with grain sizes from 10 to about 500 µm admixed, the fillers being added depending on the product in amounts of 5 - 50% to the mixture.

The blowing agents used for the foam layers are those which are otherwise customary for plastisols Products such as azodicarbonamide, oxibis-benzenesulfohydrazite, azoisobutyronitrile, toluenesulfohydrazite and others. Azodicarbonamide is preferred, the decomposition temperature of which is about 200 ° C. by adding activators such as zinc oxide, zinc octoate and other known activators reduced to temperatures of 120 ° can be. In this way, the foaming temperature can be adjusted to the foam to be foamed Adjust plastic and its viscosity well. The blowing agents are in the form of fine powders (2 to 12 µ Grain size) or as a batch (rubbed with paraffin or antistatic) in quantities of 0.5 - 10% of the Mix added.

As deactivators for the areas where foaming is not desired, those for such foam mixtures known substances are used. Trimelitic anhydride, Benzotriazole or thiourea used. In contrast to the solvent-based pastes, which allow the deactivators to diffuse into the foamable layer must be present in the inventive Means of the deactivator are printed together with a means of transport. As a means of transport are e.g. liquid paraffins or liquid antistatic agents or crosslinkable derivatives of methacrylic acid. The deactivators should be in an amount of approximately 0.5-2% based on the mass of the structure Foam layer can be applied.

The mixture can also contain peroxides for crosslinking the foam and improving the Temperature resistance of the polymers both during processing and later use be added. Bactericides, antistatic agents, antioxidants etc., such as them, are also suitable as auxiliary substances are common in latex and plastic processing.

The invention is explained in more detail in the following examples.

Recipe examples example 1

Recipe for smooth foams EVA acetate content 28% 1000 kg Aluminum hydroxide 200 kg Blowing agent mixture azodicarbonamide / zinc oxide 35 kg Zinc octoate 10 kg Antistatic 10 kg Titanium dioxide 10 kg peroxide 50 kg

Example 2

Recipe for structurable foam EVA acetate content 28% 1000 kg Azodicarbonamide 20 kg zinc oxide 75 kg Zinc octoate 5 kg Antistaticum (Irgastat 51) 60 kg Titanium dioxide 10 kg peroxide 50 kg

Example 3

Recipe for structurable foam EVA acetate content 28% 1000 kg Azodicarbonamide 20 kg Zinc oxide mixture 75 kg Zinc octoate 5 kg Antistatic 10 kg Titanium dioxide 10 kg peroxide 50 kg Triethylene glycol dimethacrylate 140 kg

Process example Example 4 Manufacture of foam-containing floor coverings with scattered, chemically foamed and structured EVA dry blends

The heterogeneous, EVA foam layers containing elastic flooring can on a conventional, for PVC flooring suitable coating system can be produced. As additional equipment are on the Powder spreaders available on the market. The device used is schematic in FIG. 2 shown. The carrier material (textile, glass and similar fabrics) is unrolled (1) and storage dosing fed to the system endlessly. In the first commissioned work (2) is not shown by means of Coating device as a so-called fixing or base coat the corresponding coating material for Closing and smoothing the carrier substrate applied, heated by radiator (5) and over a Smoothing device (3) smoothed.

In the second application unit (4), the process described in Example 2 or 3 is carried out using a powder spreading machine EVA Dryblend applied and then melted in an infrared emitter station (5), however not yet chemically foamed or cross-linked.

The melted foam surface is additionally smoothed over a smoothing drum (6) and solidified. The smooth foam surface obtained is then pressed using a printing machine (7) Multi-colored print design applied using polymer binder printing ink. In a third commission (8) the print layer is covered by a transparent coating compound. The so obtained Fabric is heated to 160-200 ° C in a drying / gelling oven, which creates the EVA dryblend layer foams - only partially when structured - and through which peroxides are cross-linked. Drying and The reaction of the transparent cover layer takes place at the same time.

To improve the backing material and the overall springback behavior of the floor covering construction can again use a foamable EVA dryblend in another powder spreader (4) be applied as described above, which is then melted in accordance with (5), (3), (9), solidified, smoothed and foamed. A final surface treatment using a smoothing unit (3) is used to homogenize the foam surface. If necessary, a structured one can also be used here Roll are used in the manner of an embossing. The material web is cooled in the cooling section (10) and then removed from a storage device and reel (11) of the system. If necessary, a Intermediate control with ready-made single rolls take place, which are then the finished goods warehouse can be fed directly.

Alternatively, the covering described above can also be produced in a batch process by Lengths of approx. 500 m each rolled up after one or more of the above steps, temporarily stored and be fed to the next processing station at a later time.

Claims (11)

1. Process for the production of latex-, PVC- and plasticiser-free synthetic material floor and wall coverings in a width of up to 4 or 5 m which contains one foamed layer and a carrier layer,
   characterised in that on the carrier layer, subsequently present under the foamed layer, there is scattered on a powder mixture consisting of

   100 parts of a latex-, PVC- and plasticiser-free thermoplastic polymer with a melt index (MFI 190°C/ 2.16) of 2 to 40

   0 - 100 parts filling materials

   0.5 - 7 parts propellant

   0 - 30 parts adjuvants

   in an amount corresponding to the desired thickness of the foamed layer and melted at temperatures of 70 - 110°C, smoothed between smoothing rollers and foamed up at temperatures of 120 - 200°C and that the foam layer, after the gelling, smoothing and possible printing, is covered with one or more further not foamed covering layers and foamed up.
2. Process according to claim 1, characterised in that the foam layer is foamed up only after covering with the covering layer or covering layers.
3. Process according to claim 1, characteriseu in that the carrier layer and/or additional covering layers are produced in appropriate manner from a powder mixture according to claim 1 without propellant and without the foaming step.
4. Process according to claim 1 or 2, characterised in that the propellant contains an activator and the foam layer is, after the smoothing, partly printed with a deactivator.
5. Process according to one of claims 1 - 4, characterised in that the propellant is azodicarbonamide, the activator a zinc compound and the deactivator a triazole.
6. Process according to one of claims 1 - 5, characterised in that, as substrate, there is used a gel layer, fabric or release paper on which is possibly applied a priming layer of non-foamed polymers.
7. Process according to one of claims 1 to 6, characterised in that the mixture is composed of a grain fraction of the size 0 - 600 µm, preferably of 10 - 400 µm.
8. Process according to one of claims 1 - 7, characterised in that the polymer has a melt index (MFI 190°C/2.16) of 10 - 20.
9. Process according to claim 7 or 8, characterised in that the crystallite melting point of the polymer lies at 70 - 110°C.
10. Process according to claim 8 or 9, characterised in that the polymer is a co-polymer of ethylene and vinyl acetate, polyethylene, polypropylene, co-polymer with polyvinyl acetate, polymethyl methacrylate, polyethylene acrylic acid ester co-polymer, polyethylene acrylic acid ester, maleic acid anhydride co-polymer.
11. Process according to one of claims 1 - 10, characterised in that the mixture contains a crosslinker, especially an organic peroxide, in an amount of up to 10 parts.

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