EP0604896A1 - Manufacture of laminated parquet - Google Patents

Abstract

The use of wood lamellae (6), produced by slicing squared timber and subsequently dried, as a top layer (4) in the manufacture of laminated parquet is described. <IMAGE>

Description

The invention relates to the use of wood slats produced in a certain way as a covering layer in the production of parquet laminates.

In contrast to the previous practice, in which individual pieces of solid wood were put together to form a parquet surface at the place of installation, prepared parquet units of a certain surface size are used today, in which the individual parquet elements are already firmly attached to one another, referred to below as the support layer. These plate-like structures are then joined together to form a closed parquet floor. It is essential for the aesthetic feeling that the joints between two adjoining plate-like parquet units look no different than the joints between the individual parquet elements on such a unit, so that the entire floor covering still gives the impression that it is made up of individual elements small parquet elements put together and not from prefabricated units, whose larger grid is still recognizable.

In order to achieve this goal, the parquet units are machined precisely on their outer edges and provided with tongue and groove in order to join them as seamlessly as possible. A prerequisite for this is of course a very high dimensional stability of the parquet unit as a whole.

For this purpose, the parquet units are generally designed as a laminate body, which acts as a covering layer for a large number of the tight joined-together parquet elements and as a carrier layer, which can be designed as a main underlay or as an intermediate layer, for example has a layer of sawn wooden bars, which runs generally transversely to the longitudinal direction of the parquet elements if they have a certain oriented longitudinal extension, and possibly with an underlayer is provided from a peeled veneer, which should bring about a cross-sectional symmetry of the arrangement for reasons of dimensional stability.

The carrier layer can alternatively also consist of a plate-shaped wood material, for example a particle board or a fiberboard. It is only decisive for the choice of material that the backing layer has a flat surface and that it absorbs the stresses which are generated in the cover layer during air conditioning, so that warping of the parquet element is prevented.

While the top layer slats are made from selected types of wood, mostly spruce, pine or oak, but also other types of hardwood, such as beech, robinia, teak or maple, the load-bearing intermediate layer generally consists of spruce wood, not least for cost reasons.

The lamellae, which can have thicknesses of up to approximately 10 mm, are produced from suitable squared timbers in the conventional production method as thin boards by sawing.

Although attempts have been made to use thin veneers as the top layer, there are various disadvantages. So conifers can be because of their density differences between early and late wood and because of their knots bad knife, ie cut across the grain. Thicker veneers made from hardwood for the parquet top layer tend to crack and break, since thicker veneer sheets can hardly absorb the deflection or kinking of the trunk by the veneer knife. Thinner veneer sheets can curl up, which is no longer possible with "veneer boards".

Thinner veneer layers meet the requirements for the decorative appearance of the floor surface, but they significantly limit the possible uses and the lifespan of the parquet. On the one hand, the thin veneer layer lacks the necessary compressive strength and, on the other hand, after a first phase of use has passed and the floor has become unsightly, this parquet cannot be sanded and thus "regenerated" because the top layer is too thin. As a result, veneer-coated laminate parquet has not become established.

Since the parquet elements for the gluing of the units must have a certain minimum dry matter content, the squared timbers were dried before they were divided into individual wooden slats for the parquet elements. Depending on the starting position of a slat in squared timber or log, drying the slats only after the squared timber has been cut can lead to different shrinkage in thickness, which necessitates increased reworking of the slats.

Processes have recently become known with which thin wood lamellae are produced by simply cutting from a squared timber. Also, for example, in DE-A-39 36 312 Process described, according to which solid wood composite panels are made from cut thin boards by gluing. However, these solid wood composite panels consist exclusively of such cut boards, so that the uniformity and equal pretreatment of the material ensures a homogeneity in the board, which has also led to an acceptable result when using cut boards for such products.

If thin boards are produced from a squared timber by cutting, the squared timber should be moist and preferably also have an elevated temperature. This means that the boards produced by cutting still have to be dried after their manufacture. As already mentioned above, this has the certain disadvantage with boards that are to be manufactured with the highest possible accuracy that different dry shrinkage can occur. Also, the thin boards can experience certain undesirable distortions and curvatures when cutting, which cannot always be completely reversed on the insulated board.

Surprisingly, however, it has been shown that, despite these disadvantages, parquet units with a very good dimensional stability can be produced if cut wood lamellae are used for the cover layer in the production of such parquet laminates as explained at the beginning.

Although a certain amount of post-processing, which was originally regarded as disadvantageous, must be accepted, the processes for cutting boards are now in process has been improved in such a way that, if desired, a different dry shrinkage can already be taken into account when cutting. In addition, it has not been taken into account that the production of sawn wood lamellas also includes further machining steps, which, however, are not carried out on the lamellas themselves but on the squared timber beforehand. If, for example, wood blades of exactly the same thickness and identical external dimensions are to be produced from precisely cut saw blades from a squared timber, the squared timber must be brought to an exact size after it has dried, during which it can also warp due to drying shrinkage.

When using cut wooden lamellae according to the invention which have been dried after cutting, the step of mechanical processing is shifted to a precise width according to the invention from the squared timber to the already cut lamellae.

While in the manufacture of multi-layer laminate products from cut wooden lamellae alone, surface grinding of the wooden lamella to the same thickness seems unavoidable, because when several layers are joined together, differences in thickness or gradations within the middle layers can lead to non-even contact of adjacent layers, surface grinding of cut lamellae can occur with the Production of the parquet laminates according to the invention is dispensed with, since only one layer of wooden lamellas is used on the more or less just assumed base, the carrier layer. The visible surface of the cover layer is anyway machined, ie ground, to produce the finished product.

This means that improved parquet laminates can be produced using cut and then dried wood lamellas, the disadvantages in the dimensional accuracy of cut lamellas, on closer inspection, not having the expected effect, particularly in the production of parquet laminates. In addition, there is of course the already known advantage of considerable raw material savings in the case of cut slats.

It has also been found that cut wood slats of satisfactory quality, i.e. especially high compressive strength, especially from nobler and harder woods that can be used for the top layer of parquet laminates. The wood lamellas are always cut in the longitudinal direction of the wood, whereby certain disadvantageous effects on the surface structure, such as result when cutting very thick veneers according to the conventional veneer peeling technique, can be avoided. The cut lamellae allow the parquet laminate to be sanded repeatedly to remove unwanted signs of use, so that the lifespan of this laminate is close to that of conventional solid wood parquet.

A peeled veneer can still be used for the lower layer of the parquet laminates. However, the use of cut wooden lamellas in the sense of this application would also be possible.

The wooden lamellae dried after cutting apparently have better dimensional stability due to the uniformity of the drying, which seems to be incomplete when drying squared timber.

Two typical usage examples for cut slats for the production of parquet laminate are described below.

Fig. 1

eine Ansicht eines Drei-Schicht-Laminats,

Fig. 2

eine Ansicht eines Zwei-Schicht-Laminats, Trägerschicht aus Spanplatte.

Show it:

Fig. 1

a view of a three-layer laminate,

Fig. 2

a view of a two-layer laminate, carrier layer made of chipboard.

Fig. 1 shows the view of a three-layer laminate parquet 2. The top layer 4 is about 4 mm thick, with particularly high quality parquet, the thickness of this top layer can be up to 10 mm. The cover layer 4 as a wear layer can be sanded down several times in order to eliminate traces of use. It is constructed in Fig. 1 from slats 6, which extend over the full length of a laminate element, i.e. extend over a length of approx. 2.30 m. Two slats next to each other result in the width "B" of a laminate element. This embodiment, in which the slats extend over the full length of the element, is generally referred to as a plank.

The carrier layer 8, on which the cover layer 4 is glued, consists of approximately 5 mm thick strips of sawn spruce boards which, lying loosely next to one another, are at right angles to the direction of the fibers the top layer slats are arranged. The length of the sawn spruce boards thus corresponds to the width B of the laminate element. The width of the sawn spruce boards is between 2 and 4 cm. A first long side 10 of the laminate element has a continuous groove 12. The opposite long side 10 of the laminate element has a continuous spring 14. This interlocking tongue and groove connection ensures that the laminate elements joined together have a joint that is not larger than the joint between the two lamellae 6 of the top layer of a laminate element. The joint tightness can be increased, among other things, by gluing together adjacent laminate elements. The carrier layer 8, ie the sawn spruce boards lying side by side, have a flat surface. It has been found that between the cut and dried lamellae 6 of the cover layer 4 and the sawn spruce board of the carrier layer 8, full-surface gluing can be achieved without further processing steps. Distortion of the laminate elements is effectively prevented by the fiber orientation of the carrier layer 8, which is offset by 90 ° with respect to the cover layer 4.

The dimensional stability is further increased by gluing the carrier layer 8 to an underlayer 16 which lies opposite the cover layer 4. The lower layer 16 consists of an endless beech peeled veneer, the fibers of which run parallel to those of the cover layer. In addition, the lower layer 16 also facilitates the processing of the laminate elements 2, since the elements now have a closed underside. The three-layer laminate shown in FIG manufactured in such a way that the lamellae of the cover layer are cut and dried and brought to an equal width, while the spruce boards of the carrier layer are sawn in the dried state, the elements of the carrier layer are then glued, with a peeled veneer 16 on the underside and on the Provide the top with fins 6. After pressing, the long sides of the laminate elements are provided with grooves and tongues. Finally, the top of the top layer is sanded and sealed with a single or multi-layer lacquer or glaze coating. The laminate elements have a predetermined standard size of approximately 15-25 cm in width and approximately 1.60 to 2.50 m in length and a thickness between 10 and 18 mm.

A two-layer structure for a parquet laminate is shown in FIG. 2. The cover layer 4 consists of two adjacent rows of lamellae. These slats 6 are about 30 cm long and placed in rows one behind the other. The adjacent rows are staggered so that the butt joints 18 of the slats one behind the other do not continue over several rows. This type of installation is referred to as ship floor parquet. The slats 6 of the cover layer 4 are glued to a carrier layer 8. The carrier layer 8 consists of a 12 mm thick chipboard, so that the thickness of the finished laminate element is 17 mm with a wear layer of 5 mm. The chipboard is a low-tension material that safely absorbs the stresses that may be caused by the top layer when the climate changes, so that no distortions occur. 2, the carrier layer is on the long sides 10 of the Laminate elements with opposite grooves 12 and tongues 14 provided. The longstrip parquet is also sold in dimensions of approx. 12-25 cm wide and up to 2.50 m long. However, other formats, for example plates of approx. 50 x 50 cm, can also be produced. The top layer slats have a width of approx. 6-8 cm and a length of approx. 20-40 cm.

The top layer 4 of parquet laminates is preferably constructed so that the "open" sides of the slats 6, i.e. the sides, which were facing the knife during the cut, rest on the carrier layer 8, so that the "closed" sides of the slats 6 form the top of the wear or cover layer.

Of course, further arrangements of cut and dried slats 6 on a carrier layer 8 are conceivable, for example the mosaic parquet, but FIGS. 1 and 2 show essential examples of use.

Typical types of wood used for the production of parquet laminates are oak, beech, robinia, teak and maple, as well as spruce and pine for plank parquet laminates.

Claims (9)

Use of wooden slats produced from a squared timber in its longitudinal direction by cutting and then dried for the production of parquet laminates, having a cover layer made of these wooden slats and at least one further carrier layer which does not consist of cut wooden slats. Use according to claim 1 with the proviso that the wooden lamellae with their closed side facing away from the knife when cutting from the square timber are arranged facing outward in the top layer of the parquet laminate. Use according to claim 1 or 2 of cut wood lamellae of a thickness of up to 10 mm. Use according to at least one of claims 1-3 with the proviso that the wooden slats used are produced from oak, beech, robinia, teak or maple. Use according to at least one of claims 1-4 with the proviso that the wooden slats are brought to an exact width dimension by machining their longitudinal edges before they are joined together to form the covering layer of the parquet laminate. Use according to at least one of claims 1-5 for parquet laminates, which consist of the wooden lamellas as a top layer, sawn wooden bars as a middle layer and a peeled veneer as a lower layer. Use according to at least one of claims 1-6 for a parquet laminate whose at least one further wood layer or intermediate layer consists of spruce wood rods. Use according to at least one of claims 1-5, characterized in that the carrier layer consists of a plate-shaped wood material. Use according to claim 8, characterized in that the carrier plate consists of a particle board.

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