MULTILEVEL PLASTIC SHEETS OR - PLATES WITH TRANSPARENT SURFACE LAYER

The available invention concerns multilevel floor mat plastic sheets or - plates (in the following briefly plastic sheets called) with transparent surface layer, procedure for their production as well as their use.

Under multilevel plastic sheets or - plates i.S.d available invention are understood planar formations, which of several, one above the other arranged layers to consist.

Multilevel plastic sheets on polyvinyl chloride (PVC) - basis, with a transparent surface layer as Nutzschicht, apply for decades as floor mats. Such multilevel plastic spells exhibit for example following structure:

• transparent surface layer (clear layer) (thickness 0.2 to 0.8 mm)
• Intermediate layer, if necessary colored and/or examined (thickness 0.2 to 0.4 mm)
• Lower layer, color arbitrary (thickness 1.0 to 2.5 mm)
• if necessary noise control layer e.g. from foamed plastic, cork or Korkment (thickness 1.5 to 2.0 mm).

For the representation of an examination either the surface layer (clear layer) can in or polychrome be behind-printed alternatively and/or the intermediate layer in or polychrome be printed on. This can be achieved in economical way with a gravure technique.

Beside these multilevel (heterogeneous) plastic sheets also so-called homogeneous plastic sheets are well-known, i.e. einschichtig trained plastic sheets, with which all components are in such a manner mixed with one another, daß it continuous (homogeneous) characteristics over the entire cross section of the plastic sheets from the top side to the lower surface exhibit.

With homogeneous plastic sheets an examination is reached by use of multi colour granulates. Usually those become the polymere bonding agent, pigment (e), fillers and if necessary auxiliary materials of containing granulates in compression aggregates, as e.g. Kalandern, double volume presses or static presses a plastic sheet or - plate processes. Production-determined however only a more or less lengthwise colored examination is available with the homogeneous plastic sheets, whereby one is strongly reduced in the sample choice. Besides it is äuß only cost-intensively to reequip production plants already existing so daß homogeneous plastic sheets with modified samples develop, as far as this in the context of the production of homogeneous plastic sheets is at all possible. Such sample and color changes are however necessary, in order to react to the changing needs of the market.

Opposite the homogeneous plastic sheets with continuous, lengthwise examination the multilevel (heterogeneous) plastic sheets with transparent surface layer exhibit the advantage, daß one when its production complete freedom concerning the color and sample choice has, because the sample can be produced in various way by Hinterdrucken of the transparent surface layer and/or printing the highest intermediate layer on.

A further advantage over homogeneous plastic sheets is to be seen with the multilevel plastic sheets therein, daß the surface layer and the highest intermediate layer to only be colorconstant must, in order to receive plastic sheets with continuous colors. All layers which are under it can be from arbitrary, also changing color, so daß it is possible to train into this lower layer scraps of the plastic sheets or also recycling material.

As mentions initially, floor mats on PVC basis, with a transparent surface layer are as Nutzschicht, for a long time in the trade. In the last years however the disposal of PVC or PVC haltigen plastic materials became increasingly more problematic, since the Chlorgehalt PVC with the Deponierung a danger potential represents and with the burn by PVC hydrogen chloride is set free, which is the combustion plants corrosive and gesundheitsschädiich.

Floor mats on PVC basis contain auß erdem always also a softener. This content of softeners brings further disadvantages with itself, since the softener can migrate into the adhesive, with which the floor mat was stuck together, so daß the adhesive strength is lowered. The softener can also out-sweat, whereby the floor mat becomes a splash guard which can be cleaned with difficulty and the softener represents a drains system for migrating coloring materials, whereby discolorations develop, which cannot be removed any longer. Besides volatile softeners represent a further problem for the environment.

For the aforementioned ones reasons pollution free plastics were looked for as replacement for PVC, with which products, e.g. multilevel floor mats, be manufactured can, which possess similarly good characteristics, as on PVC basis the manufactured, however their disadvantages not to exhibit. For it primarily plastics on the basis of olefinischen polymers are applicable, like e.g. polyethylene (PE), polypropylene (PP), ethyl propylene copolymers, as well as copolymers ethyls with other olefinischen insatiated connections.

Thus for example in EP-B1-0 321,760 for the production of homogeneous, an ethyl vinyl acetate (EH) is suggested PVC-free plastic sheets - copolymer as polymere bonding agent using.

Also in DE-A1-41 14,085 a PVC suitor Fu&szlig becomes; floor mat suggested, with which homogeneous plastic sheets are manufactured, the one EH copolymer preferably together with a polyolefin as bonding agents contain. These courses can be doubled or tripliert.

Furthermore 27,107 becomes a multilevel PVC suitor Fu&szlig in DE-C1-41; floor mat suggested, whereby a Fuß floor mat on EH basis with a transparent foil from a linear ethyl copolymer of low density and/or very low density is doubled and/or tripliert.

From EP-A-0 213,441 a foil or a foil course is for furniture well-known, which consists of at least two layers, i.e. a polyolefin foil and a layer, which are arranged over the polyolefin foil. The polyolefin foil can up to 30 parts by weight a ethyl Acrylsäureester Acrylsäureterpolymerisats contain.

From EP-A-0 353,068 a coat film from a bottom layer and a substrate layer is well-known. The substrate layer consists of a resin composition, the 10 to 95 Gew. - % of an ethyl copolymer umfaß t, which can be an ethyl methyl acrylate copolymer, an ethyl ethyl acrylate copolymer, an ethyl n-butyl acrylate copolymer or a Ethylen-2-Ethylhexylacrylat-Copolymer. On the substrate layer a metal can become vapour-deposited. The coat film, on which the metal separated, has a broad application, e.g. as packing material.

EH copolymers are relatively low-priced and are so variable, da&szlig in their application; they in practically all layers of a multilevel plastic sheet to be used know thereby can a multilevel plastic sheet from layers with as homogeneous a polymer composition as possible be developed. This is for reasons of the production-internal recycling of edge strip, starting wastes etc. of the individual layers of importance.

On the other hand EH copolymers exhibit however substantial disadvantages.

After the list of the maximum job concentrations (out: The new chemical law, manual of the dangerous materials, Eberhard Quellmalz, Weka publishing house, February 1992) is classified vinyl acetate under the carcinogenic group of IIIB. Thus itself substantial problems and risks can with the production of EH-containing plastic sheets or - plates and their use as floor mats result, in particular regarding those constantly aggravating safety regulations.

The remainder monomer content of vinyl acetate is with commercial EH polymers within the range of 0,1 to 0.5 Gew. - %. This vinyl acetate portion läß t by following treatment, e.g. stripping procedure, not continue to decrease. Thus it can come to substantial loads in insufficiently ventilated areas, since from floor mats, which contain commercial EH polymers, slowly and continuously vinyl acetate is delivered.

EH shows a relatively small thermal stability, i.e. EH is inclined to split off to it, at higher temperatures acetic acid. The noticeable acetic acid splitting off begins for EH already above approx. 180 °C. Thus problems, if other polymers are to be added like ISO-tactical Polypropylene e.g. high-melting, result around mechanical characteristics (Verschleiß firmness to improve hardness) since at the then necessary higher processing temperatures already the acetic acid splitting off begins. This acetic acid splitting off beeinfluß t the characteristics of the EH and thus also the characteristics of the floor mats, which contain EH, negatively, since in the polymer chains double bonds are produced, which can to be oxidatively attacked and to a dismantling the polymers lead.

As alternative to the EH copolymers in particular ethyl copolymers of low density (density range about 0.915-0.935 g/cm3) are e.g. suitable, like copolymers ethyls and Buten or Octen (1). This ethyl copolymers of low density permit one just like EH copolymers auß erordentlich high filling with usual fillers in connection with controllable flexibility and hardness. However such ethyl copolymers of low density exhibit pronounced olefinische characteristics; they are for example very nonpolar. These olefinischen characteristics affect among other things negatively the sticking together barness such ethyl copolymers of the containing multilevel plastic sheet. Auß erdem it is problematic, such plastic sheets, as with floor mats usual, with a finish or a lacquer to provided, around its Anschmutzverhalten and its Verschleiß to improve characteristics, since the adhesion between the plastic sheet and the finish is insufficient or the lacquer.

Task of the available invention is it from there, multilevel floor mat plastic sheets or - plates, in particular such with a transparent surface layer to make available PVC and EH-freely is contained and no softener. Furthermore these plastic sheets are to possess the favourable characteristics of well-known multilevel plastic sheets or - plates, without exhibiting however their aforementioned disadvantages.

A further task is it, a procedure for the production of these multilevel floor mat plastic sheets or - plates to indicate.

These tasks are solved through in the patent claims defined floor mat plastic sheets or - plates and the procedure for their production.

Those erfindungsgemäß EN floor mat plastic sheets or - plates consist of a surface layer and at least a further layer, whereby at least one of the layers contains at least one ethyl alkyl acrylate copolymer. Preferably the surface layer is transparency and exhibits a portion of ethyl alkyl acrylate copolymer.

Surprisingly one found, daß those erfindungsgemäß EN floor mat plastic sheets or - plates, which are PVC and EH free and contain no softener, nevertheless an excellent flexibility and Verschleiß firmness exhibit. Furthermore they have the advantage, daß with their processing higher temperatures, for example temperatures of above approximately 180 °C, without impairment of the polymer characteristics to be used can. This is favourably, there thus for the optimization of the mechanical characteristics of the plastic sheets, like e.g. Verschleiß firmness, high-melting polymers, like ISO-tactical polypropylene types to be added know, without daß , as in case of the use of EH copolymers, acetic acid abgespalten becomes. A further advantage that erfindungsgemäß EN multilevel floor mat plastic sheets is their comparatively small water absorption, itself on the Maß stability and thus on the performance characteristics affect favorably, since a higher water absorption leads to pouring the plastic sheets, whereby blisters and tears in the bonding slits can develop. These impair the adhesive strength and offer attack regions for dirt.

Schließ lich surprisingly one found, daß those erfindungsgemäß EN multilevel floor mat plastic sheets excellently with polymere-rich dispersions, how they are contained in ground preservative agents, to be in-maintained can. This means, daß the Pflegemittei in a desired layer thickness very well on the plastic sheets cling and during a sufficiently long period the floor mat protect. This is possibly erfindungemä&szlig on the increase of the polarity of the plastic surface of the courses or - plates by the presence of the polar groups into that; used ethyl alkyl acrylate copolymers to lead back.

Those erfindungsgemäß EN floor mat plastic sheets can be provided also with a usual factory-installed applied finish, which clings likewise excellently. Floor mats from plastic materials will provide frequently also on their utilizable side for the improvement of the performance characteristics with a lacquer. Also for this those are erfindungsgemäß EN plastic sheets outstanding suitably, since also a such lacquer clings excellently, without daß it a special pretreatment of the plastic sheets requires. A suitable lacquer can be for these purposes a usual solvent-free two-component lacquer. Preferably the lacquer is a solvent-free lacquer hardenable by aktinische radiation (e.g. UV light). However it can be favourable with a low content of ethyl Alkyacrylat copolymer in the surface layer to submit the surface of the plastic sheet before applying the finish or lacquer of a corona discharge.

The treatment of the back of the surface layer and/or the top side of the intermediate layer with a corona discharge, arranged under the surface layer, is also favourable, if the aforementioned sides of the layers are to be printed on with a sample.

Those erfindungsgemäß used ethyl alkyl acrylate copolymers know a component of each of the layers of the multilevel floor mat plastic sheets or - plates is. In case of the transparent surface layer the content can within the range of approximately 5-70 Gew. - %, related to the weight of the surface layer amount to, preferably 10-50 Gew. - % and more prefers 20-30 Gew. - %. In the other layers than the transparent surface layer contain the polymere bonding agent of 20-80 Gew. -, 40-70 Gew prefer %. - and 60-70 Gew particularly prefer %. - % at least one ethyl alkyl acrylate copolymer, related to the weight of the polymere bonding agent.

The portion of the alkyl acrylate in ethyl alkyl acrylate copolymers amounts to thereby about 4-30 Gew. - %, preferably 10-15 Gew. - %. The alkyl acrylate content depends on the desired characteristics of the layer. The higher the content of alkyl acrylate in the ethyl alkyl acrylate copolymer is, the more softly and more flexibly becomes the copolymer.

The other layers than the transparent surface layer that erfindungsgemäß EN floor mat plastic sheets or - plates contain 20-60 Gew. -, 30-50 Gew prefer %. -, particularly 35-45 Gew prefer %. - % polymere bonding agent.

Into that erfindungsgemäß EN floor mat plastic sheets or - is the alkyl acrylate plans in the ethyl alkyl acrylate copolymer a methyl acrylate, a Ethylacrylat, Butylacrylat or any mixture this copolymers, particularly preferentially is preferably Ethylacrylat, since it e.g. is less smell intensive than Butylacrylat the ethyl alkyl acrylate copolymer is thus preferably a copolymer, which became to keep selected by Copolymerisation by ethyls with an alkyl acrylate, from methyl acrylate, Ethylacrylat, Butylacrylat or any mixture from it. This copolymers can be made in actually well-known way, preferably by high pressure polymerization of the gaseous phase.

Those erfindungsgemäß used ethyl alkyl acrylate copolymers can both statistic copolymers and block copolymers be, whereby statistic copolymers are preferential.

As mentions managing, the presence of at least the transparent surface layer that lends to ethyl alkyl acrylate copolymers erfindungsgemäß EN multilevel floor mat plastic sheets an excellent compatibility and adhesion with polymere-rich dispersions, how they are contained in ground preservative agents e.g., as well as with finish or lacquers. Besides are the abrasion strengthening firmness and Verschleiß firmness improves clearly. The presence one or several ethyl alkyl acrylate copolymers in the surface layer impairs also the transparency of this layer essentially not, so daß problem-free any sample on the lower surface of the surface layer and/or the top side of the underlying intermediate layer to be printed can be noticed and this sample by the viewer practically genuinely can. This is groß it advantage of the multilevel plastic sheets with transparent surface layer opposite the homogeneous plastic sheets.

Beside that ethyl alkyl acrylate copolymers can for the optimization of the performance characteristics of the plastic sheets in the surface layer further polymers be used. For the controlling of the hardness characteristics crystalline, ISO-tactical polypropylene types or polypropylene copolymers can be added. Further the polymer or polymer mixture of the surface layer knows ethyl propylene the nth polymers (EPDM) for the optimization of characteristics, like hardness, impression firmness, abrasion resistance, resistance against Anschmutzung etc. by addition of for example ethyl and propylene Homo and copolymers, random copolymers of ethyls and propylene, ethyl propylene india rubbers (EPM), styrene Isopren Stytrol (SIS) - and/or styrene butadiene styrene (SBS) - block copolymers, as well as copolymers by ethyls with at least a further alkene with up to 10 carbon atoms, like Octen, to be modified. For the increase of the tenacity a high-molecular and/or ultrahigh-molecular polyethylene of high density (PE-HMW and/or PE-UHMW) can be preferably added.

If necessary can be admitted to the surface layer usual aids, as for example Antioxidantien, Antistatika, lubricants and working on aids. Antioxidantien and Antistatitika, in particular in the transparent surface layer are recommended in order to protect and on the other hand static loadings prevent on the one hand the plastic sheets against oxidative dismantling, those with the production of the plastic sheets unpleasantly are negatively beeinflu&szlig and with the later use of the plastic sheets their Anschmutzverhalten; EN.

Furthermore pigments and coloring materials can be added to the surface layer, in order to already produce before printing on an essential structure or a basic colour.

The Hinterdrucken of the surface layer and/or printing the underlying layer on can take place in usual way, for example in the halfauto+typical low pressure with engraved cylinders, whereby a pretreatment of the surfaces with a corona discharge is preferential.

For the other layers than the transparent surface layer that erfindungsgemäß EN multilevel floor mat plastic sheets are applicable as polymers in principle all polymers, which can be used also in the transparent surface layer, as well as Homo or copolymers of ethylenisch insatiated connections or any mixture of it.

These other layers (intermediate layer, lower layers) can to be e.g. exhibited further usual fillers, as chalk, kaolin, talcum powder, wood flour, quartz powder, dolomite, silica, heavy spar and Schiefermehl or any mixture of it whereby the portion of the fillers, related to the respective layer 40-80 Gew. -, 50-70 Gew prefer %. - and 60-65 Gew particularly prefer %. - amounts to %.

In all other respects can be added to the further layers the aids, as well as pigments and coloring materials, how they are descriptive for the surface layer. Thus, daß one with the intermediate layer and each further layer which is available if necessary (lower layer) regarding the color is not bound, can for these layers, in particular the lower layers Recyclatmaterial be admitted. It can itself around wastes from current production, so-called new mass waste, how edge sections of the courses or starting wastes act, or also around material, which became to receive the recycling in the way from plastic wastes. The auxiliary quantity of Recyclat depends on the kind of the material and it can only as much Recyclat be admitted, daß the demanded material properties of the plastic sheets to be fulfilled.

If necessary those can erfindungsgemäß EN floor mat plastic sheets or - plates with a fleece or a reinforcing fabric to be provided, which is brought in for example between the intermediate layer and the next lower layer, in order to lend to the plastic sheet a still higher firmness and dimensional stability.

Those erfindungsgemäß EN floor mat plastic sheets can be provided at the lower surface with a warming and/or a noise control layer, e.g. from a foamed plastic, a fleece of sufficient thickness, a textilen fabric, cork or Korkment exist.

Those erfindungsgemäß EN floor mat plastic sheets or - plan are manufactured, by the individual layers (foils) separately manufactured and anschließ end with one another in well-known way verschweiß t become.

For the production of the individual foils the polymere bonding agent and the aids if necessary used, fillers, Recyclatmaterial etc. are before-mixed and e.g. plastifiziert over aggregates, like interior mixers, two-wave extrusion, planet roller extrusion or rolling mill. The plastifizierte mass with suitable machines becomes following, as converts Kalandern or double volume presses if necessary together with a fleece or a reinforcing fabric to the layer of desired thickness. Afterwards the appropriate layers can be behind-printed and/or printed on. Connecting the individual foils by Verschweiß EN takes place then for example by means of a Auma or a double volume press with cooling zone, whereby the latter is preferential because of the reduction by sticking problems at the machine. At the same time or anschließ end can, if this is desired, on the lower surface of the plastic sheet a warming and/or a noise control layer in usual way be applied.

Those erfindungsgemäß EN multilevel floor mat plastic sheets were subjected the among other things following tests:

1. 1. Milling stability in the ball milling attempt (test provision for flexible surfaces gemäß DLW of AG-internal company standard): This examination serves (with reference to DIN 16,952 T 1-5, DIN 16,851, DIN 18,173) for the determination of the behavior of compound surfaces with divorce and milling movements, similarly a wheelchair demand. The examination takes place by means of a Verschleiß testing set “Stuttgart” gemäß DIN 51,963, which was modified in such a manner, daß the weight 34 kg amounts to, the ball a diameter of 20 mm exhibits, a cooling blower is present, and a milling segment without oscillating motion is used. A test specimen (190 x 190 mm) with a thickness of the plastic sheet received in each case or - plate was glued on with double-sided tape an aluminum plate. Before the examination the test specimen in an air-conditioning rack in the normal climate (DIN 50 014-23/50-2) was stored at least 24 hours. At the time of the execution of the examination the test specimen on the rotation plate of the abrasion machine is tightened and the speedometer is adjusted to 1000 double milling strokes. Execution takes place under cooling (cooling blower). As Maß staff for the evaluation is valid the number of obtained double milling strokes up to the blistering. Minimum requirement for the quality “chair-roll-suitably” is daß at least 1000 double strokes up to the blistering to be accomplished can.
2. 2. Impression behavior according to DIN 51,955
3. 3. Impression behavior in brief Stempeldurckprüfung (test provision for flexible surfaces gemäß DLW of AG-internal company standard): This against DIN examination leaned serves 51,955 for the short term determination of the resetting and hardness of the surface. As testing set a Dickenme&szlig becomes; turns out (diameters of the even surface area of the cylindrical pressing stamp: 6 mm, Meß pressure: 0.03 N/mm2) and an impression testing set (diameter of the circular surface area of the pressing in stamp: 11.3 mm) gemäß Exp. 4,1 and 4,2 of the DIN 51,955 uses. Three test specimens (100x50 mm) are distributed over the web width, whereby the selvedge distance amounts to at least 50 mm. Before the examination the test specimens are stored at least 48 hours in the normal climate according to DIN 50 014-23/50-2. The execution of the examination takes place in the following steps:
   1. - Thickness measurement and marking of the Meß place
   2. - Test specimen on impression equipment centrically place, by tricks at the spindle wheel Meß clock in zero position, Vorkraft bring to 3 N
   3. - stoß free load within 5 seconds, full load 1 kN
   4. - Impression depth after one minute read off and test load remove
   5. - Test specimen remains in the equipment, after a further minute under Vorkraft the remainder impression is read off.

The determination of the resetting (elasticity) and the hardness index (index) is computed with the help of the following formulas: - Resetting (%): Impression (1 min) - remainder impression (1 min) impression (1 min) x 100 - hardness index, HE: Impression (1 min) thickness mm x 100

1. 4. Loss in thickness after 20 cycles according to DIN 51,963
2. 5. Maß - and resistance to deformation according to DIN 51,962
3. 6. Trennversuch of the layers according to DIN 53,357
4. 7. Fire examination according to DIN 4102

All quantity specifications are so far not differently indicated in Gew. - % and all temperature specifications in °C.

The following example is to describe the invention further.

All managing components were mixed in an eddy mixer (company Henschel) and plastifiziert in a stamp kneading machine GK5 of the company Werner & Pfleiderer approx. 5 minutes. (Mass temperature 190 to 200 °C). The plastifizierte mass was given on a rolling mill (company Schwabenthan) at a roller temperature of 185 °C, and continues to homogenize. The mass was then taken off on a 4-Walzenkalander (company Berstorff) to a foil with a thickness by 0.4 mm.

One receives in this way a product in form of a foil, which is sufficiently transparency, in order to show after Hinterdruckung if necessary accomplished the print format clearly.

All managing components were mixed in an eddy mixer (company Henschel) and pastifiziert in a stamp kneading machine GK5 of the company Werner & Pfleiderer approx. 5 minutes. (Mass temperature approx. 180 °C). The mass became of a rolling mill of the company Schwabenthan (roller temperature 140 °C) directly a 3-Walzenkalander (company Berstorff) supplied and coated on a mat SH 50 of the company Schuller directly. (Foil thickness 0.3 mm).

One receives in this way a foil, which is provided with an intensifying fleece reinforcement.

In place of the new mass prescription specified above just as proportionately gemahlener edge strip waste of a finished surface or also Fremdrecyclat can be used into quantities of up to 50%, related to the total quantity of the layer.

The prescription components were mixed in an eddy mixer (company Henschel) and plastifiziert in a stamp kneading machine GK5 of the company Werner & Pfleiderer approx. 4 minutes. (Mass temperature 180 to 190 °C). The mass became on a rolling mill of the company Schwabenthan (roller temperature 150 °C) directly a 4-Walzenkalander (company Berstorff) supplied and a foil with a thickness of 0.5 mm manufactured.

Like managing manufactured intermediate layer on a 4-Farben photogravure printing machine of the company Dornbusch, from role to role, was printed on with intermediate and final drying process. A printing ink of the company K was used + E, Stuttgart within the special color range. The bonding agent was co-ordinated with the substrate. The printing substrate was submitted before the printing of a corona discharge. (Speed of approx. 40 m/min.).

The order for drying of the printing ink was with approx. 15 to 20 g/m2 when full surface printing for each pneumatic cylinders on.

The single foils became verschwei&szlig the following total structure; t:

In addition all monolayers (foils) on a Reyon Mitläufer of the company Mehler of a Gummibandauma (company Berstorff) were supplied and at a drum temperature of 100 °C to the overall system verschweiß t. The lower layer and intermediate layer were warmed up first by means of IR-Stahler to a surface temperature of 180 °C. Speed of the volume 2 m/min, volume printing 200 bar = 4 bar partial pressure. Anschließ end the surface in the same processing step with reverse current order for roller, UVinterlace-cash lacquer igen with a 100% (type LM 720, company Lott, Bielefeld) with an order quantity from 15 to 20 g/m2 one coated. The networking of the lacquer took place in an UV channel downstream, which was equipped between 50 and 100% with 4 UV-Stahlern with a respective output of 120 Watt/cm, adjustably. The first Stahler was adjustable for gloss adjustment in the height.

In this way received multilevel plastic sheet exhibits the following characteristics specifying for floor mats:

      2,25 ± 0.1 mm

      > 5,000 double strokes up to the blistering

Schüsselung not meß bar

      B2