EP1226303B1 - Linoleum floor covering - Google Patents

Abstract

The invention relates to an electrically conductive floor covering based on linoleum, comprising a wear layer and a sub-layer, whereby the floor covering has an electrical volume resistivity R1 according to EN 1081, of a maximum 10<7 >Omega. The invention also relates to a method for producing said floor covering.

Description

The present invention relates to an electrically conductive linoleum-based floor covering, which comprises a wear layer and an underlayer, the floor covering having an electrical volume resistance R ₁ according to EN 1081 of at most 10 ⁷ Ω, and a method for producing the floor covering.

The market is increasingly demanding PVC-free, light-colored floor coverings with low electrical resistance, in particular with a volume resistance R ₁ of at most 10 ⁷ Ω (volume resistance R ₁ according to EN 1081 or electrical leakage resistance R _A according to DIN 51 953). At the moment this requirement is only met by electrically conductive rubber floor coverings. Such PVC-free, electrically conductive rubber-based floor coverings have been described, for example, in DE 34 40 572 A1, DE 196 49 708 A1 and DE 35 45 760 A1.

However, there has recently been an increased demand for floor coverings based on renewable raw materials, the classic example of which is linoleum floor coverings. A conventional linoleum floor covering has a relatively high electrical resistance of approximately> 10 ¹⁰ Ω. A linoleum floor covering of this type cannot therefore be used in rooms whose floor covering must have a certain electrical dissipation value, such as, for example, in operating rooms in hospitals, laboratories and computer rooms. For such applications, it is known to reduce the volume resistance of the linoleum flooring by adding electrically conductive fillers such as special carbon blacks or metal powders. Additions of special carbon black, however, have the disadvantage, on the one hand, that the useful properties of the linoleum floor covering deteriorate because of the relatively large amount of carbon black required to achieve sufficient electrical conductivity. On the other hand, when adding carbon black to the linoleum mixture, there are practically no more color options. Even when using metal powders to improve the electrical conductivity, the color design options are considerably limited and, in addition, there are changed properties in the mechanical behavior as well as an increase in weight and a significantly reduced thermal insulation of the floor covering. Therefore, it has so far not been possible to achieve a conductive linoleum floor covering with a light color and a volume resistance R ₁ of less than 10 ⁸ Ω.

DE 34 16 573 and WO 99/10592 relate to electrically conductive linoleum-based floor coverings which are made electrically conductive or antistatic by adding at least one derivative of imidazole, imidazoline, benzimidazole or morpholine or a cation-active compound thereof. However, such floor coverings always only have a volume resistance R ₁ of approximately <10 ⁸ Ω, this value additionally depending on the air humidity. In dry air, even these values cannot be achieved.

WO 99/04085 describes a linoleum-based floor covering which is electrically conductive and in which the linoleum wear layer has an irregular pattern, for example a marbling, from differently colored areas. The differently colored areas are sharply delineated from each other and have different electrical conductivity. Again, the electrically conductive areas of this floor covering contain large amounts of a conductive filler and are therefore colored very dark. Although a greater range of variation in the color design seems possible according to this publication, according to example 4 a third of the floor covering has a dark color. Furthermore, the volume resistances of the floor coverings according to the document (6), despite a relatively dark color, always have only> 10 ⁷ Ω. Even with such a method, it is therefore not possible to produce floor coverings which are sufficiently electrically conductive and which essentially have a light color tone throughout.

An object of the present invention is therefore to provide a linoleum sheet suitable as a floor covering, which has a lower volume resistance R ₁ , in particular a volume resistance R ₁ of at most 10 ⁷ Ω, which is also not as independent of the air humidity, and at the same time a light color tone having. Another object of the present invention is to provide a method with which such a linoleum floor covering can be produced.

These tasks are identified with those in the claims Objects solved.

In particular, a linoleum-based floor covering is provided which is electrically conductive and which comprises a wear layer (2) and an underlayer (3), the floor covering having an electrical volume resistance R ₁ according to EN 1081 of at most 10 ⁷ Ω.

1. Der Durchgangswiderstand R₁ gemäß EN 1081, welcher dem Ableitwiderstand R_A gemäß der DIN 51 953 entspricht, ist der elektrische Widerstand eines Bodenbelags, gemessen an einer Probe zwischen der Dreifußelektrode auf der Oberfläche des Bodenbelags und einer Elektrode auf der unmittelbar gegenüberliegenden Unterseite.

2. Dahingegen ist gemäß EN 1081 der Erdableitwiderstand R₂, entsprechend dem Erdableitwiderstand R_E gemäß DIN 51 953, der elektrische Widerstand eines Bodenbelags, gemessen an einem verlegten Bodenbelag zwischen einer auf die Oberseite gedrückten Dreifußelektrode und Erde.

To determine the electrical resistance of floor coverings, EN 1081, which has replaced DIN 51 953, defines the following values:

1. The volume resistance R ₁ according to EN 1081, which corresponds to the leakage resistance R _A according to DIN 51 953, is the electrical resistance of a floor covering, measured on a sample between the tripod electrode on the surface of the floor covering and an electrode on the directly opposite underside.

2. On the other hand, according to EN 1081, the earth leakage resistance R ₂ , corresponding to the earth leakage resistance R _E according to DIN 51 953, is the electrical resistance of a floor covering, measured on a laid floor covering between a tripod electrode pressed onto the top and earth.

In the prior art, "electrically conductive" floor coverings are floor coverings which have an earth leakage resistance R ₂ according to EN 1081 of <10 ⁹ Ω.

According to the invention, the floor covering has a volume resistance R ₁ of at most 10 ⁷ Ω, measured according to EN 1081. The earth leakage resistance R _{2 of} the floor covering is preferably at most 10 ⁷ Ω, measured in accordance with EN 1081.

The figures show:

FIG. 1 is an illustration of a schematic cross section through a floor covering (1) according to a preferred embodiment of the present invention along line AA of FIG. 2. An underlayer (3) and a wear layer (2) are arranged on a carrier (4). Particles (6) which comprise a conductive filler can be sprinkled into the wear layer (2). According to this embodiment, a conductivity web (5) is also arranged on the side of the carrier (4) facing away from the lower layer (3).

Figure 2 shows a schematic plan view of the underside of a floor covering (1) according to an embodiment of the present invention. A conductivity web (5) is arranged on the side of the carrier (4) facing away from the lower layer. This web (5) can be connected when laying the floor covering, for example, with a copper tape flag (7), by means of which the floor covering is grounded by connecting it to the earth potential.

The floor covering according to the invention has a linoleum-based underlayer and a wear layer or top layer based on linoleum. The Floor covering preferably has a total thickness of approximately 2 mm to approximately 6 mm, in particular about 2 mm to about 4 mm.

According to the invention, the electrical conductivity of the underlayer is preferably brought about by mixing at least one electrically conductive filler into the raw linoleum. Carbon black and metal powder are preferred as such electrically conductive fillers, and a filler can be used alone or in combination. When carbon black is used as the conductive material, the concentration, depending on the type of carbon black, is preferably about 1 to 20% by weight, more preferably about 3 to 15% by weight, based on the weight of the conductive compound. For example, Ketjenblack® EC-300J (Akzo Nobel), Printex® XE 2 (Degussa AG) or one or more other commercially available carbon blacks can be used as carbon black. When using metal powder as the conductive material, the concentration is approximately 1.5 to 40% by weight, based on the weight of the conductive mixed mass. The amount used depends on the density and particle size of the metal powder. For example, magnetite powder, aluminum, bronze and VA powder can be used as the metal powder. Any mixture of carbon black and one or more metal powders and a single metal powder or a mixture of several metal powders can also be used. The quantity ratios for mixtures of carbon black and metal powder should be selected so that the volume resistance R _{1 of} the underlayer, which is in contact with the wear layer in the floor covering, is preferably ≤ 10 ⁷ Ω (EN 1081), more preferably ≤ 10 ⁵ Ω (EN 1081).

The underlayer can contain other chemical additives that increase conductivity of the linoleum continue to improve. Examples of such chemical Additives, as well as exemplary amounts used, are related to the composition of the wear layer described below and can can be applied analogously in the lower layer.

In addition to the additives mentioned above, the lower layer has one usual composition. In particular, in the mixed mass usual additives, such as processing aids, antioxidants, UV stabilizers, Lubricants and the like may be included, depending on the Can be selected.

The underlayer preferably has a thickness of 0.6 to 1.4 mm.

The wear layer or top layer of the floor covering according to the invention is the surface visible in the installed floor covering. According to the invention, it can have a higher volume resistance R ₁ than the lower layer and preferably contains only small amounts of electrically conductive filler. A certain conductivity of the wear layer can be achieved by essentially colorless chemical additives in the linoleum matrix for the wear layer. Morpholine and / or at least one derivative of imidazole, imidazoline or benzimidazole or a mixture thereof is preferably used as the chemical additive. Cationally active compounds with a quaternary nitrogen atom of such compounds are particularly preferred. The chemical additive is preferably incorporated into the raw linoleum mass in an amount of 0.5 to 15% by weight, more preferably in an amount of 4 to 10% by weight, based on the total weight of the linoleum mass of the wear layer. When such chemical additives are used, according to a preferred embodiment of the invention, diatomaceous earth, which is often also referred to as silica, can be used as the sorbent. 3 to 5% by weight of diatomaceous earth, based on the weight of the linoleum mixture, are preferably used.

According to the invention, the wear layer can have a light color and plain or multi-colored patterned. In the wear layer preferably in place of the least proportionally provided Spot color an electrically conductive filler such as carbon black and / or metal powder and / or conductive fibers or a mixture thereof is added.

For the purposes of the invention, conductive fibers are in particular graphitized Plastic fibers or plastic fibers made with epoxy graphitized Material is covered. Such conductive fibers can be added of graphite in the plastic itself or by coating small ones Plastic particles are made with graphite, and usually have one gray color. Because of their small size and however, they appear to the human eye in small amounts almost colorless.

The wear layer preferably contains 0.1 to 5% by weight, particularly preferably 0.1 to 2% by weight of carbon black, and / or 0.1 to 8% by weight, particularly preferably 0.1 to 3% by weight. -% metal powder before. The conductivity of the linoleum wear layer can be improved to below 10 ⁷ Ω by such low-dose additions. Furthermore, due to this small proportion of electrically conductive filler in the wear layer, the volume resistance R ₁ surprisingly no longer depends so much on the air humidity even when the chemical additives mentioned above are added.

Furthermore, the top layer comprises the usual linoleum floor coverings Components such as binders (so-called Bedford cement or B cement a partially oxidized linseed oil and at least one resin as a tackifier), at least one filler and optionally at least one colorant. As Fillers are usually softwood flour and / or cork flour (at simultaneous presence of wood flour and cork flour typically in the Weight ratio 90:10) and / or chalk, kaolin (china clay) and heavy spar used. The mixed mass usually contains at least one Colorants such as a pigment (e.g. titanium dioxide) and / or other common ones Colorants based on inorganic and organic dyes. As Colorants can be any natural or synthetic dyes as well inorganic or organic pigments, alone or in any Combination. A typical linoleum composition contains, based on the weight of the wear layer, approx. 40% by weight of binder, approx. 40 wt.% organic fillers, approx. 15 wt.% inorganic (mineral) fillers and approx. 5% by weight of colorant. Furthermore, in the Mixed mass of conventional additives, such as processing aids, antioxidants, UV stabilizers, lubricants and the like can be contained, which in Dependency of the binder can be selected.

The wear layer preferably has a thickness of 1.4 to 3.6 mm, particularly preferably from 1.4 to 2 mm.

It was surprisingly found that the volume resistance of the Composite of wear layer and lower layer through the conductive lower layer compared to the volume resistance of the wear layer is improved. Without wanting to commit to a mechanism is for them Embodiment assumed that the low interference of a conductive material as bridges, or electrical Pipes, between the surface of the flooring and the conductive Underclass can serve. As shown in Figure 1, this is sufficient Embodiment at least some of the interference of a conductive Materials (6) or agglomerates of these through the entire thickness of the Wear layer (2) and make a connection between the Surface of the floor covering and the conductive sub-layer (3) forth.

Another advantage of the present invention can be that only small amounts Wear layer containing electroconductive filler to a certain extent are "protective" or "balancing" over the lower layer. Since the Underlayer contain larger amounts of an electrically conductive filler mechanical properties often deteriorate. This but worse properties come in the overall network of Floor coverings according to the invention not to be worn, since above the underlayer the wear layer has good mechanical properties. For example, a somewhat more brittle underlayer can be created using an elastic one Wear layer to be protected.

Furthermore, the linoleum floor covering according to the invention preferably comprises a carrier. A material based on natural and / or synthetic woven or knitted fabrics and textile materials be used. Examples include jute fabrics and blended fabrics natural fibers, such as cotton and rayon, glass fiber fabrics, with Adhesion promoter coated glass fiber fabric, mixed fabric made of synthetic fibers, Fabrics made of core / sheath fibers with e.g. a polyester core and a sheath made of polyamide. As an adhesion promoter for Glass fiber fabric can, for example, be a coating of the glass fibers a styrene-butadiene latex can be used.

According to one embodiment of the present invention, the A back stroke is applied to the side of the carrier facing away from the lower layer which is preferably electrically conductive and more preferred is not applied in the form of a continuous covering, but in the form a web or strip preferably 50 to 100 mm wide and 50 up to 200 µm thick. This preferably web-shaped backstroke extends continuously over the entire length of the floor covering. He is in electrical contact with the sub-layer and can be used when laying the floor covering, for example, contacted with a copper tape flag be connected to the earth potential, so that the flooring can be grounded. While laying in the prior art conductive flooring uses electrically conductive special adhesives to make contact with earth potential, it is possible according to this embodiment of the present invention, only a copper ribbon flag connected to the web-shaped back line to connect the earth potential and an ordinary glue for that To use laying the flooring.

Advantageously, a web-shaped backstroke is provided when the Back of the flooring with a stamp also by Printing process applied. Aqueous carbon black dispersions and Polymer dispersions, for example a latex, are used, which up to 8% by weight, preferably 4 to 6% by weight of an electrically conductive Filler, preferably carbon black. In particular, this includes preferably web-shaped backstroke a polymeric material, which an electrically conductive filler therein as described above involved includes. One bound in a polymeric material electrically conductive filler has the advantage that the backstroke does not rub off.

The present invention further relates to a method for producing the Linoleum-based flooring according to the invention.

For the production of the floor covering according to the invention, the usual methods for the production of multi-layer floor coverings become.

As a first step, the method according to the invention comprises the application the linoleum mass of the lower layer on a support. To do this first all components as described above for the Linoleum mass in a suitable mixer, e.g. a kneader, Rolling mill or extruder, to a base material that is as homogeneous as possible (Mixed mass) mixed. The mixed mass thus obtained is one Rolling mill (e.g. a calender) fed and under pressure and one Temperature of usually 10 to 150 ° C (depending on the recipe and of process engineering) pressed onto a carrier material. When pressing the The rolling mill (e.g. the Roller distance of a calender) adjusted so that the resulting Floor covering sheet receives the desired layer thickness. In the invention Linoleum flooring is the thickness of the underlayer like usually described above 0.6 mm to 1.4 mm.

Next, the linoleum skin for the wear layer is made, which is preferably colored and / or patterned.

In the simplest case, particles of a suitable size can be used for this electrically conductive filler in a single or multi-colored linoleum mass for the wear layer, possibly together with particles of colored Fillers, are sprinkled and the linoleum mass to a linoleum skin be calendered.

According to one embodiment, colored chips can also be one Linoleum mass, which is preferably an electrically conductive filler contains, sprinkled on linoleum skins made in this way and into them be pressed in.

Furthermore, according to one embodiment, a colored or patterned Linoleum mass can be produced. To do this, first use mixed masses or bases of different colors made separately, to skins rolled and granulated. After that, different colored granules are mixed together mixed and then fed to the rolling mill (e.g. a calender) and shaped as fur. In special cases, the mixture is made of different colors Granules before application to the carrier material in Rolling mills stretched into striped skins, rotated by 90 ° on top of each other laid and then calendered with friction, the known, the result in sample images based on natural marble.

According to a further embodiment, sharply contoured patterns can can be achieved by laying different rolled skins on top of each other (duplicating) and brought into close contact and only then crushed together become. This creates particles that consist of two different adhering parts exist. A part preferably consists of non-conductive mixed mass and the other part preferably conductive compound. The multilayer composite of the rolled skins can be used for Preparation of the particles e.g. granulated, cut, broken or be ground. The composite is preferably processed into granules. Now are these particles or the granules of parts different Mixing compound fed to a rolling mill, such as a calender, and onto one Rolled carrier, there is an irregular pattern in which the different colored, each connected, but also from each other separate areas made of conductive and non-conductive material with sharp contours are separated from each other and the colored areas are practically pure i will be preserved. These colored areas are the most conductive Filler material containing and therefore more or less dark to black colored mixed mass edged.

In addition to the above-mentioned processes for producing a patterned Linoleum fur can be used for all other conceivable processes.

Such a rolled skin of the wear layer is then with the lower layer pressed into a two-layer linoleum flooring.

Then the two-layer linoleum floor coverings from the Linoleum subjected to usual ripening treatment.

According to one embodiment of the method according to the invention on the Back of the floor covering at least one preferably web-shaped Back stroke is applied. This imprint is preferably by a Printing process applied to the back of the flooring.

example

A two-layer floor covering according to the invention was produced, by placing a bottom layer and a wear layer on a jute backing were calendered, and the resulting composite then matured has been. The compositions of the lower layer and wear layer were as described in Table 1 below.

The leakage resistance R _{A of} the lower layer and the leakage resistance R _{A of} the upper layer are also shown in Table 1. underclass top layer component Content [% by weight] Content [% by weight] cement 38.0 34.0 wood flour 37.2 32.2 Carbon black, conductive 4.0 0.5 Titanium dioxide - 7.9 Quaternary ammonium salt 6.7 6.7 diatomaceous 2.4 4.0 aluminum hydroxide 11.7 13.05 pigments - 0.85 zinc oxide - 0.8 Leakage resistance R _A [Ohm] 6 x 10 ³ to 10 x 10 ³ 2 x 10 ⁶ to 10 x 10 ⁶

The combination of lower layer and wear layer had a volume resistance R ₁ according to EN 1081 of 1.9 x 10 ⁶ to 3.8 x 10 ⁶ Ω.

Claims (12)

1. Electrically conductive floor covering based on linoleum, comprising a wear layer (2), a lower level (3), and a backing (4), with the wear layer (2) comprising 0.1% to 5% by weight carbon black and/or 0.1% to 8% by weight metal powder in relation to the total weight of the wear layer (2), with the lower layer (3) containing as at least one electrically conductive filler material 1% to 20% by weight carbon black and/or 1.5% to 40% metal powder in relation to the conductive mixed mass, with the floor covering having a contact resistance R₁ per EN 1081 (April 1998) of a maximum of 10⁷ Ω.
2. Floor covering according to Claim 1, with the lower layer (3) having a thickness of 0.6 mm to 1.4 mm.
3. Floor covering according to Claim 1 or 2, with the wear layer (2) comprising a chemical additive for increasing conductivity.
4. Floor covering according to Claim 3, with the chemical additive being selected from morpholin and/or at least a derivative of imidazol, imidazolin, or benzimidazol or a mixture or a quaternary ammoniumsalt thereof.
5. Floor covering according to one of the preceding claims, with the wear layer (2) having a bright color.
6. Floor covering according to one of the preceding claims, with the wear layer (2) as such having a multicolor pattern.
7. Floor covering according to one of the preceding claims, with the wear layer (2) having a thickness of 1.4 mm to 3.6 mm.
8. Floor covering according to one of the preceding claims, with an electrically conductive web (5) being arranged on the side of the backing (4) facing away from the lower layer (3).
9. Floor covering according to Claim 8, with the electrically conductive web (5) comprising an electrically conductive filler material.
10. Method for producing a floor covering based on linoleum according to one of Claims 1 through 9 comprising

    the application of the lower layer (3) onto a backing (4) and

    the forming of the wear layer (2) on the lower layer (3).
11. Method according to Claim 10 with at least one back coating in the form of an electrically conductive web (5) being applied to the back side of the floor covering.
12. Method according to Claim 11, with the web-like back coating (5) being applied through a press process.

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