FR2625938A1 - Method for assembling decorative papers in the lamination of planar or shaped objects based on lignocellulose and objects thus obtained - Google Patents

Abstract

Method making it possible to assemble, for the purpose of creating a decoration, resin-impregnated papers intended for the lamination of panels or shaped objects based on lignocellulose. It consists firstly in producing on the one hand one or more incisions 4 [female part(s)] in the background paper 1 and, on the other hand, one or more overhangs 5 [male part(s)] in the attached piece(s) of paper 2 and then in placing, as the lamination is built up, overhanging parts 5 of the decorative paper 2 in the incisions 4 in the background paper 1. This assembly makes it possible to secure the various constituent pieces of paper with one another during the subsequent operations and more particularly the first operation of passing through the press. The invention may be used when producing specific decorations during orders relating to a limited number of units of laminated products.

Description

 The present invention relates to methods allowing the production of simple decorations during lamination, using resin-impregnated paper, panels and molded objects shaped more particularly based on lignocellulosic particles, to constitute what is commonly called Particle Panels. Laminate laminates (or PPSM).

 Laminated Particleboard Panels, or PPSM, that is to say particleboard, the surfaces of which consist of one or more layers of paper impregnated with thermosets under pressure, can be manufactured in various ways.

 In some cases, and in the case of flat finished products, the particle board is first produced in raw form, then carefully calibrated and sanded. It is then taken up again, placed on one or more so-called "balancing" or "counterbalancing" paper (s) as if it were to constitute its back side or counter face, and covered with one or more paper (s). having to constitute its apparent front side or "decor" side, the two families of paper which can moreover constitute a symmetry on either side of the support. The assembly thus formed is finally placed in a hot press for thermosetting under pressure of the papers.

On leaving the press, the edges are not coated and are even edged with a saw.

 In other cases, and again in the case of flat finished products, the production is carried out "in situ", that is to say that the core of lignocellulosic particles and the two surfaces of impregnated paper are thermoset together in one operation. For this purpose, on one or more balancing paper (s), the cake (or "mat") of glued wooden particles is conformed, then one or more paper (s) are placed on the decor side: the assembly is placed between two plates of a hot press (after having been or not previously placed in a cold prepress) to carry out the simultaneous polymerization of the core and the faces. At the exit, and as before, the edges are not coated and must be edged.

 In still other cases, but here in the case of finished products molded into shape as in the case of the WERZALIT QR process for example, the production is also carried out "in situ". But here, the glued particles of wood are conformed in a cold mold and they are prepressed to form a preformed cake. This cake is placed on the paper (s) impregnated with counterbalancing, and the whole in turn deposited in a hot mold where it undergoes a first hot pressing, with simultaneously cutting of the paper on the periphery . After opening the press, the paper (s) on the front side are (are) deposited (s) on the cake thus pressed a first time when hot. A second hot pressing is carried out on this assembly with simultaneous cutting of the papers on the periphery. In this type of process, the edges are coated.

 In all cases, the upper paper on the front side, which may or may not be covered with a transparent film, provides the decor for the finished product.

 Most often, it is solid in color and particularly white in color to allow standard use and therefore be of minimal cost.

 For mass-produced productions, it can be determined to be economically viable to use paper made multicolored by printing a particular pattern (s) more or less complex.

 For medium or small productions, on the other hand, a special impression will generally be too expensive and alternatives must be found.

 For special productions, a subsequent multicolor effect is sometimes achieved by painting the previously finished product in plain decor, generally white. However, this solution is not simple and remains penalizing anyway.

 For small, medium (as well as large) productions, the apparently most interesting solution is that of combining, in obtaining a multicolored decor, different colored or drawing papers.

To operate such an association, and to obtain for example the motif illustrated in FIG. 1, one can
- either (figure2A) superimpose the two papers by depositing the smallest (1) on the largest (2) which constitutes the bottom,
- Either (Figure 2B) operate by marquetry by juxtaposing to each other the edges of the two previously cut paper, complementary to each other, in accordance with the desired final drawing.

But in case A of FIG. 2, the implementation of hospitality encounters in practice two obstacles
- The placement of the decor paper (s) (i) on the background paper (2) is difficult for the operator who has no point of reference to locate exactly.

 - When the press is closed, the papers are moved from their original position by the inevitable displacement of air.

 In case B of FIG. 2, if the location is made easy for the operator during positioning, the problem of moving the papers when the press is closed is not solved.

 We then thought of securing the decor paper (s) to the background paper by one (or more) welding point (s) between these papers after positioning: the problem of the relative displacement of the papers during press closing is then resolved, but not that of the difficulty of positioning itself by the operator.

 The method according to the invention makes it possible to avoid both the difficulty for the operator to find the correct location of the decor paper and the risk for the latter of being displaced when the press is closed.

The process used in fact serves simultaneously as a positioning marker and for fixing this positioning.

 To achieve this result, the process involves the association of two simple transformations: one relates to the background paper ,.

the other on the decor paper (s). If we take the example presented in figure 1, the principle transformations will be as follows
for the background paper, incisions (4) will be made with the punch, as indicated in FIG. 3A, simultaneously with the operation of pre-cutting the reams of paper.

 for the decor paper (s), protruding parts (5) like the angles in the case of FIG. 3B, will be provided on the perimeter of the decor during the pre-cutting of the reams of paper room.

 The transformations thus carried out will be used, according to the male-female principle: when setting up the decoration, either directly on the pressed "mat" (3) or during a prior preparation operation, the operator uses the incision first as a benchmark then as the female part of the assembly by adapting the projecting part of the decor paper to it, used therefore as the male part.

 it is obvious that a decorative paper may itself include one or more incisions and thus serve in turn for attachment to another decorative paper in the case of producing more complex patterns.

 It is also obvious that the protruding parts (5) of the decor papers may be of various shapes (FIG. 4) in order to be adapted as best as possible to the requirements for producing the motif of the final decor.

 The process which is the subject of the invention can be used in all cases where, during the lamination of objects based on lignocellulose, it is desired to be able to easily and economically produce complex and varied decorations using papers impregnated with thermosetting resins in standard stock.

 A particularly interesting application can be the decorative stratification of Melamine Laminated Particle Board and molded objects according to WERZALIT OR type processes.

Claims (4)

 1) A process which makes it possible, during the lamination by thermally hardening papers, of thermosetting resins of flat or shaped objects based on lignocellulose, to produce various decorations from standard papers, characterized in that the background papers (i) comprise one or more incisions (4) and the decor papers (2) include one or more appendages (5), the incisions being intended to receive the appendices, the decor and background papers being thus easily associated and made integral so that said association is kept until the end of the stratification operations.  2) Method according to claim 1, characterized in that the incisions (4) are made with a punch during the precut of the reams of background paper.  3) Method according to claim 1, characterized in that the appendices (5) are provided during the drawing of the perimeter of the decor paper and made during the pre-die cutting of the reams of decor paper.  4) Method according to claim 3, characterized in that incisions (4) can be made simultaneously with punching during the pre-cutting of the reams of decor paper.  5v laminated flat product based on lignocellulose characterized in that it is produced by the implementation of any one of the above claims.  6) Product in the form of a lignocellulose-based laminate, characterized in that it is produced by the use of any one of claims 1 to 4.