Stock material or miscellaneous articles – Structurally defined web or sheet – Including components having same physical characteristic in...
Reexamination Certificate
1998-03-16
2001-01-23
Le, H. Thi (Department: 1773)
Stock material or miscellaneous articles
Structurally defined web or sheet
Including components having same physical characteristic in...
C428S323000, C428S331000
Reexamination Certificate
active
06177179
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an integral, board-like component, in particular for use as a kitchen working surface, comprising a visible side and a rear side, wherein the visible side comprises a layer consisting of a polymer matrix filled with a first, inorganic filler, the specific density of which is greater than the specific density of the polymer matrix, as well as a process for its production.
The invention also relates to the use of the integral, board-like component not only as a kitchen working surface but also as a partition, facing panel, table top, washstand top in bathrooms, door panel, furniture front or wall paneling.
BACKGROUND OF THE INVENTION
Integral, board-like components of the type described at the outset are known in various forms, for example from DE-38 32 351-A1, according to which a resin with a filler formed at least predominantly of quartz particles has a denser packing of the filler in the regions of the component which are subject to considerable wear and tear during use than on the back of the component.
This is achieved by allowing the filler to settle at least to a certain degree in the case of the casting mass consisting of resin and filler which is filled into the mold, and thus a concentration at the visible side of the component containing the regions subject to wear and tear is achieved.
With this process, components with very good functional properties can be produced, for which reason these components have also found a wide acceptance on the market, in particular in the form of sinks. In particular, the abrasion resistance, the resistance to scratching, the cleanability as well as the granite-like appearance of the visible side resulting from a corresponding selection of the filler number amongst the very good functional properties.
These positive functional properties are also of great value, above all, in the case of board-like materials, such as, for example, working surfaces in the kitchen, washstand tops in the bathroom etc., but it has been found that it is very difficult or even impossible to ensure a good planarity when the components have larger dimensions. In addition, the density of such components is considerably higher than the density which is customarily obtained for chipboard and this results, in the case of working surfaces 20 to 44 mm thick, in components which are very difficult to handle.
When planar components are obtained during production, a bending of the board is observed at the latest during changes in temperature, namely during changes in temperature such as those which often occur during the transportation of such boards in trucks, during which storage (for example overnight in the truck) at temperatures of between −15 and −20° C. very often occurs (for example in Scandinavian countries) while during the day with corresponding sunshine temperatures of up to 80° C. can be reached in the transport vehicle. Short storage times at different temperatures, for example in the range of hours, can already be sufficient to result in a permanent deformation of the board which can no longer be reversed and so the component can no longer be used following transportation.
Alternatively hereto, chipboard is, of course, conceivable as carrier with a thin, filled plastic layer, the filled layer having a similar composition to the visible side of the components described above. The problem with this layered construction is that the overall board is difficult to process since, in principle, different tools are required to machine or process the visible side (thin, filled layer), on the one hand, and the chipboard, on the other. In addition, chipboard has the disadvantage that it swells at higher levels of humidity and, in particular, during direct contact with water and so this type of board can be used, above all, in damp or humid rooms and particularly in kitchens as well only with reservations. The same applies for chipboard with a decorative, high-pressure laminated surface.
SUMMARY OF THE INVENTION
The object of the present invention is to propose an integral board with similar functional properties but produceable in a simple manner with a good planarity and with a large layer thickness, the board being preferably endowed with a low specific weight and, in addition, preferably with a screwing capability such as that applicable for conventional chipboard material.
A board should also preferably be insusceptible with respect to increased humidity and, in particular, direct contact with water.
DESCRIPTION OF THE INVENTION
This object is accomplished in accordance with the invention, in an integral, board-like component of the type mentioned at the outset, in that the filler content of the first filler in the visible side layer is 50 to 90% by volume, that the rear side comprises a layer which is formed from a polymer matrix filled with a second, inorganic filler, wherein the proportion of the polymer matrix in this layer in % by volume differs quantitatively by 20% at the most from the volume content of the polymer matrix in the visible side layer and wherein the specific density of the second filler is less than or equal to 0.6 g/cm
3
.
With such a board it is ensured, on the one hand, that a sufficiently large filler content is present on the visible side layer to guarantee the good functional properties such as those known from the state of the art while, on the other hand, the construction of the rear side layer with a proportion of the polymer matrix which differs only slightly in % by volume, compared with the visible side layer, not only ensures that the boards can be produced in a relatively simple manner with a very good planarity but also that the planarity of the board is maintained during changes in temperature with differences in temperature of 100° C.
Due to the low density of the second filler, the relatively high density of the filler on the visible side is, as it were, compensated and so components with a specific total density of approximately 0.7 g/cm
3
(typical value for chipboard used in a conventional manner) can be achieved.
With a view to a desired long-term stability of the planarity of the board-like component, a zone which essentially comprises no fillers, i.e. consists essentially of pure polymer, is to be avoided between the visible side layer and the rear side layer.
If such formulas are nevertheless intended to be used, a somewhat higher % by volume proportion of the polymer on the visible side layer is selected to better stabilize the planarity of the board-like component and so, in this case, a compensation of stresses can take place.
The cause of stresses occurring in the component, in particular when subjected to changes in temperature, is attributable, in particular, to the fact that the polymers forming the polymer matrix have a coefficient of thermal expansion which is many times greater than that of the inorganic fillers typically used. With a view to this, it is, of course, also possible to provide a certain compensation with a variation of the layer thicknesses and the ratio of the layer thicknesses to one another.
The rear side layer, in particular in parts which are not first of all located on the rear side surface, may comprise hollow spaces such as pores, which serves to further reduce the weight of the board or rather reduce the specific weight of the overall board. However, it is also important in this case for the proportion of the polymer matrix in the rear side layer adjacent to the surface in % by volume to differ quantitatively by 20% at the most from the volume content of the polymer matrix in the visible side layer.
Advantages are obtained during the production of the inventive component with a view to the desired integral layer construction when a layer is arranged between the visible side layer and the rear side layer which comprises reinforcing fibers in a polymer matrix. The reinforcing fibers may be loosely distributed in the polymer matrix or, however, be a fiber fleece or fabric or the like saturated with polymer. A particularly simp
Birnbeck Walter
Geier Josef
Hock Klaus
Paternoster Rudolf
Schock Friedrich
Le H. Thi
Schock & Co. GmbH
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