Decorative sheet and processes for the production of sheets

Abstract

A decorative sheet arranged on the outside or inside of buildings is composed of a compression-molded core made from one or more core layers. The core comprises cellulose fibers and/or wood fibers, bound to one another by a hot-curing resin. Each core layer is composed of wood fibers and/or of cellulose fibers having lengths from 0.3 to 30 mm, and is containing pigments or is without pigments. The pigments are uniformly distributed within the core layer, and their proportion by weight is from above 0 to 20% by weight of the mixture made from pigments and from wood fibers and/or cellulose fibers. The pigments are colorfast, and weathering of the wood fibers and/or cellulose fibers at the surfaces of the sheet causes the original coloration of the core surfaces to change so that, when dry, the core is covered by a gray-silver patina, but substantially regains its original coloration when wet.

Description

[0001] 1. Field of the Invention[0002] The invention relates to a decorative sheet comprising a compression-molded core having one or more core layers, said core layers being prefabricated layers made from wood fibers and / or of cellulose fibers, surrounded and bound by hot-curing resin, and also to the use of a sheet of this type, and to processes for the production of the sheets.[0003] 2. Description of the Related Art[0004] Sheets made from wood chips and wood fibers with a matrix of amino plastic or of phenolic resins or cement are known from the prior art, as are plywood sheets, these having uniform density and being suitable for outdoor use or use in damp indoor areas. However, unlike laminate sheets, sheets of this type are not maintenance-free, and their marked absorption of water through the unsealed surface means that they regularly require comprehensive treatment. Absorption of water can cause severe swelling with an increase in the thickness of the sheet. These sheets the...

AI Technical Summary

Problems solved by technology

However, unlike laminate sheets, sheets of this type are not maintenance-free, and their marked absorption of water through the unsealed surface means that they regularly require comprehensive treatment.

Absorption of water can cause severe swelling with an increase in the thickness of the sheet.

These sheets then have low strength and are unsightly.

The weathering resistance of this molding is unsatisfactory.

In weathering tests there is marked absorption of water with associated edge swelling and splitting of the compression-molded core, causing surface cracking after just a few weeks.

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