Method of making decor laminate board in a single-level platen press

Two decor laminate boards are produced in a single-level platen press in each operation by forming a stack of the two laminates and a separating layer between them. The layer leaves at least portions of an edge region of the stack free so that the two boards as they are formed in the press are bonded together and can be removed from the press without relative shifting. The joined region is then trimmed off to free the boards from one another.

FIELD OF THE INVENTION 
My present invention relates to a method of producing decor laminate board 
in a single platen press, i.e. the production of a laminate board having a 
structure, pattern of texture embossed on a face of the board during the 
pressing thereof. More particularly, the method relates to the 
simultaneous production of two such boards in a single press operation in 
a single-level platen press. 
BACKGROUND OF THE INVENTION 
Decor laminate board generally comprises a laminate containing or coated 
with a hardenable synthetic resin as will be described in greater detail 
hereinafter and is generally provided along a face of the board with 
embossing, texture or other structure imparted in the pressing operation. 
The laminate can be inserted into a press in the open condition thereof 
between press platens which can be provided with embossing surfaces, the 
press can be closed to apply heat and pressure to the laminate, effect the 
embossing and cause hardening of the laminate into the board. The press is 
then opened and the board is removed. A charging device can insert the 
laminate into the press and a discharging device can remove the board from 
the press. 
Two boards can be made simultaneously in the press by forming a stack of 
two such laminates having a separating layer to which the laminates are 
not adherent, between them. The separating layer can be sprayed or applied 
as a foil between the laminates. The two boards are thus formed on 
opposite sides of the separating layer and, upon removal from the press, 
can be destacked so that the stack is separated into its components, 
namely the two boards and the separating layer. 
A laminate stack of this type has not, to the best of my knowledge, been 
used heretofore in conjunction with a single-level platen press. Rather 
such stacks are known for the production of decor laminate board in 
multilevel platen presses which have a number of press openings separated 
by respective platens and into each of which a respective stack can be 
introduced. 
Multilevel platen presses operate in conjunction with press charging 
devices and press emptying devices or discharging devices of a type 
similar to those used with the multilevel presses for the production of 
particle board, fiber board and the like. 
The laminates generally are assembled from intermediate layers of so-called 
kraft papers while the decor or patterned structure is applied to so 
called overlays which can overlie the kraft paper layers. The kraft paper 
layers may be synthetic resin impregnated special papers which can be 
assembled in a plurality of layers and covered by the overlay which can be 
a synthetic resin foil. 
The laminate is subjected in the press to heat and pressure which, compacts 
the laminate, imparts a complementary structure of the embossing surface 
to the contacting face of the laminate and hardens the laminate into a 
board. 
The fabrication of such pattern board in multilevel presses limits the 
ability for pattern changeover when, for example, frequent changeover is 
required for small lots of different structured boards. Rapid changeover 
of the embossing plates is economical only with single-level platen 
presses. 
Both single-level platen presses and multilevel platen presses are cycled 
and thus can be collectively referred to as cycling presses. It is also 
known to produce decor laminate board with continuously operating presses, 
for example, steel belt presses in which the embossing pattern or 
structure must be provided on a steel belt. Replacement of such belts is 
time consuming and difficult and the use of these presses is not 
economical when small lots of the decor laminate board are desirable or 
when frequent changes of the embossing surfaces from lot to lot is 
required. 
By contrast with multilevel presses, moreover, single-level presses operate 
in a short cycle process, a technology which is similar to that which has 
been developed for the laminating of decorative layers onto chip board, 
fiber board, or for the facing thereof. 
Single-level presses require special charging devices like, for example, 
clamping bar systems (see German Patent Document DE 22 09 901) and 
emptying devices (see German Patent Document 19 11 764) operating, for 
example, with suction lifters. Such arrangements are not suitable for the 
simultaneous production of two decor laminate boards from two laminates in 
a single operation of a single-level platen press because problems arise 
in the pressing of such laminates when a separating layer is provided 
between them. These problems are associated with a tendency of the boards 
to shift relative to one another when the press is opened or as the press 
is opened, thereby making the removal of the boards difficult, if not 
impossible. 
OBJECTS OF THE INVENTION 
It is, therefore, the principal object of the invention to provide a method 
of making a decor laminate board whereby the drawbacks of earlier methods 
are avoided and a single-level platen press can be used. 
A more specific object of the invention is to provide a method of making 
two such boards simultaneously in a single platen press in such manner 
that uncontrolled movements of the pressed boards relative to one another 
upon opening of the press do not affect fabrication operations. 
It is also an object of my invention to provide an assembly which 
facilitates the production of pressed board. 
SUMMARY OF THE INVENTION 
This object is achieved, according to the invention by providing between 
the laminates a separating layer which leaves an edge region between the 
laminates free. In the press operation, therefore, in this edge region the 
laminate boards are fused together by bonding between the synthetic resin 
of the laminates, whereby, upon opening of the press, the boards are 
bonded together and form with the separating layer, a unique assembly 
which can be removed from the press as a unit without relative motion of 
the boards. Thereafter, the joined edge region is separated by a trimming 
operation, thereby separating the boards from one another and enabling the 
destacking thereof. 
More particularly, the method of the invention can comprise the steps of: 
(a) forming two laminates containing synthetic resin; 
(b) assembling a stack by disposing a separating layer between the 
laminates so that the laminates are held apart by the separating layer 
over at least a central portion of the stack but are free to contact one 
another in at least one edge region of the stack; 
(c) inserting the stack between two press platens of an open single-level 
platen press having embossing surfaces juxtaposed with opposite faces of 
the stack; 
(d) closing the press, thereby compressing the stack between the surfaces, 
maintaining the press closed for a period of time sufficient to effect 
embossing of the opposite faces and hardening of the laminates into boards 
and bonding by the synthetic resin of the boards at the region; 
(e) opening the press and removing the stack from the press, whereby the 
boards are held together against relative shifting by the bonding at the 
region; and 
(f) trimming the region from the stack, thereby separating the boards from 
one another. 
The unique assembly of the invention is adapted to be hot pressed for 
making embossed laminate board. The assembly comprises two laminates 
containing synthetic resin, and a separating layer disposed between the 
laminates so that the laminates are held apart by the separating layer 
over at least a central portion of the stack but are free to contact one 
another in at least one edge region of the stack. The laminates are 
juxtaposed at the region so that, upon hotpressing of the assembly in a 
single-level platen press having embossing surfaces juxtaposed with 
opposite faces of the stack, the opposite faces are embossed and the 
laminates are hardened into boards and the boards are bonded by the 
synthetic resin of the boards at the region, whereby trimming of the 
region from the stack, separates the boards from one another. 
The invention is based upon the joining of the boards formed from the two 
laminates at their edge regions and the discovery that such joining does 
not adversely affect the process in any respect, since the edge regions 
must be trimmed from the boards in any event. The unit formed by the 
joining boards can be removed from the press simply with the aid of 
conventional press discharging devices, e.g. that of German Patent 
Document DE 19 11 784. The trimming itself can be effected by conventional 
devices or apparatus such as standard trimming saws. 
The joining of the two boards into an assembly allows them to be handled 
with suction devices and suction lifters and thus allows greater 
automation of the production of decor laminate boards. According to the 
invention, the separating layer can terminate short of the edges of the 
laminates so that the separating layer is geometrically similar to but 
smaller than the laminates and in the contacting edge region all around 
the separating layer, the boards can be bonded together. In plan view, 
therefore, the separating layer is smaller than that of the stack. 
It is, however, also possible to provide a separating layer which is 
coextensive with the laminates but which is provided along its edges with 
openings through which the boards are bonded together.

SPECIFIC DESCRIPTION 
In all of FIGS. 1-3, the laminate stack is represented at 1 and has its 
laminates separated by a separating layer 2 to which the laminates and the 
hardened boards are not adherent. 
In the embodiment of FIG. 1, edge regions 3 of the stack are free from the 
separating layer 2 so that the two laminates can be bonded together in 
this region and this region can be subsequently trimmed, e.g. along the 
dot-dash line 4, leaving the board and enabling the two boards to be 
separated from the separating layer. In the embodiment of FIG. 2 the 
separating layer 2 is substantially coextensive with the laminates but is 
formed in the edge region with holes 5 of circular cross section which are 
trimmed off when trimming is effected along the trim line 4. In the 
embodiment of FIG. 3, the holes 6 are elongated slots parallel to the 
respective edges of the separating layer 2 and the stack, through which 
the laminates are united and which lie in the edge region trimmed off by 
trimming along the trim line 4. 
As can be seen from FIG. 4, the single-level press 10 in which the boards 
are fabricated can comprise upper and lower platens 11 and 12, 
respectively, provided with means for opening and closing the press (not 
shown) and passages 13 in the platens through which superheated steam can 
be passed to provide the heat for the press. 
At their sides confronting the stack 14, the platens 11 and 12 are formed 
with replaceable pattern plates 15 and 16 having a structure to be 
complementarily reproduced in the board and shown as undulations and 
corrugations 17 and 18 by way of example. 
The stack 14 is formed from two laminates 19 and 20, each of which may 
comprise a number of layers 21 of synthetic resin impregnated kraft paper 
and an overlay 22 of synthetic resin or resin impregnated paper adapted to 
receive the embossing. 
The stack has a separating layer 23 between the laminates, leaving an edge 
region 24 free so that, when the pressing is closed, the boards formed 
under heat and pressure are bonded together at 25 over this edge region. 
The stack 14 is thus unitary and slippage of the boards cannot occur when 
the press is opened. The stack or assembly 1 can thus be removed as a unit 
from the press and can be trimmed along a trimming line 26 (FIG. 4) to 
form the trimmed edge 27 (FIG. 5) in the finished board 28 so that the 
latter can be separated from the other elements of the stack, namely, the 
other board and the separating layer. 
In the embodiment of FIG. 6, the unitary stack 114 is formed as described 
from two boards 119 and 120, except that the separating layer 123 has 
holes 130 therein within which the bond 125 is formed between the two 
boards. The trim line 126 here lies at the inner edge of the bores 130 so 
that, as can be seen from FIG. 7, the trimmed edges 127 are formed on the 
two boards 128 and 128' which can be separated from one another and the 
remaining portion of the separating layer 123'. 
The waste 131, consisting of the connected parts of the boards and the 
remainder of the separating layer 123 can be discarded.