DE1704016C - Method for forming a multilayer board - Google Patents

Description

shading layer, also in a known manner coated This coating is carried out, for example, by applying the liquid layer to the one that has just been stored Carrier plate, whereby an even distribution can easily be achieved by applying in liquid form is. This coated plastic sheet is then heated in an oven to below the boiling point of the lowest-boiling liquid phase. While this multilayer board is being heated in the oven, the mold prepared to receive the preheated plate. This happens because the shape z. B. by brushing or spraying a fluoride compound is provided with a separating layer so that the finished plate can later be easily removed from the mold. It has been shown that this is necessary in order to achieve a faultless Hold surface to egg. Then the mold is heated either by passing hot air over it or by heating elements arranged in the mold. The next step is the insertion of the preheated plate, and then the temperature is increased up to the amount required for deformation. The pressure is increased at the same time until the lower limit of the boiling point is exceeded

S pressure of the lowest boiling liquid phase. This pressure increase must correspond exactly to the Inquire about the associated temperature increase - Then the deformation pressure is given, but according to the present invention the temperature during-

its kept constant. After this deformation process has been completed, the fully deformed multilayer board can be removed after the pressure has been released and the temperature has decreased.
It has been shown that, surprisingly, by

* 5 the application of the method according to the invention it is possible without any particular difficulty by yourself difficult deformations of multilayer board !! to carry out and that in the case of this procedure deformed multilayer boards do not

also show blistering.

Claims (1)

ι 2 dea several weeks, even with direct! Storage of the Claim: parts in water. It was followed by a very inhospitable one economic manufacturing. Process for forming a multi-The use of acralates or even others Layered panel, the layers of which consist of 5 thermoplastics with low deformation in different temperature ranges, liquid lower temperature is possible, but these are made of materials, e.g. a multi-layer panel according to the current state of the art not enough panel with a self-shading layer, with lightfast or weatherproof and tend to yellow when the multilayer plate is preheated and the polymerisation or deformation necessary due to a pressure gradient against a desired temperature,
th shape corresponding support part reshaped I _n the USA. Patent 3 039 911 is already a is, characterized in that the method for forming a multilayer board, Multi-layer plate initially below the layers of masses with different liquid temperatures the lowest-boiling layer contains phases, described in which one preheated, then heated on the multilayer plate for forming, placed on a mold Required temperature is further heated below and deformed by a pressure gradient wad by it simultaneous increase of the multilayer by a vacuum to sink into the form gcplatte surrounding pressure up to which the murder is carried out. However, this procedure can only be used for mold temperature corresponding boiling pressure of the relatively small parts are applied and at lowest-boiling layer and that the forming ao materials whose melting point is in a range temperature during forming is one-sided, at which there is no evaporation or compounding Further increase the pressure until one of the components evaporates. For big The end of the deformation is kept constant. However, parts of the procedure are not applicable. A process for forming large parts oe- 25 writes the French patent specification 1426 614. The difficulties of forming as a result of the different Melting points are thus cor- The present invention relates to a process in which the position of low melting and deformation is formed of a multilayer board, the vapor point of which is cooled by water, while layers consist partly of liquid substances at different temperatures, which have a high melting and evaporation point , e.g. B. one is heated Such a method is not applicable, however, multilayer board with a self-shading in those cases in which the corresponding layer, in which the multilayer board is preheated, the working points are close to one another. Apart from and due to a pressure gradient against one of the desired, such a process is very complex and reshaped for the corresponding support part 35 large production quantities are not suitable,
will. The present invention is now the task Such multi-layer panels are already based on a method for reshaping a multi-edge. So describes z. B. the German Auslegeschrift schichtenplatte, some of the layers in ver-1 225 S27 a light-transparent changeable foil different temperature ranges of liquid substances or multilayer arrangement of with plastic 40 exist, z. B. a multilayer board with a Glass-bonded reaction layers, which are their optically self-shading layer. It has see properties «n dependence on the respective - namely surprisingly shown that a reshaping Reversible lighting and / or temperature is possible if the multi-layer panel is pre-changed. heats and due to a pressure gradient against one of the In these arrangements there is a reversible support part that changes the desired shape Layer of partially acetalized or molded. The solution of the given task leads ketalized polyvinyl alcohol and the like to a method which is characterized high molecular weight plastic, the free hydroxyl of which is that the multilayer plate initially below groups by secondary valence compounds partly due to the boiling point of the lowest boiling point Wasoer and partially bound to hydrate salt, so preheated layer, then for reshaping on to this which is further heated below a predetermined temperature required temperature the same or approximately the same refraction while increasing the multilayer plate dex like the high molecular weight substance. surrounding pressure to above that of the deformed The production of such multi-layer boards by the appropriate boiling pressure is the lowest therefore known. So far, however, such a layer and that the deformation temperature could be wähtige Multi-layer composite panels with self-shading deformation when one-sided further heightening animal effect due to the water content in the print until the end of the forming process reacting layer is practically not kept deformed Istant. because the deformation had to take place at temperatures of _: In this process according to the invention greater than 100 ° C and the deformation of the multilayer board or the water containing the layer comes to boiling in the process, molded parts come under overpressure with a pressure head, so and the layer through Bubble formation destroyed, The vapor formation by any of the liquid deformation phases could only be carried out, especially by water or solution, when the intermediate layer was practically anhydrous. The subsequent air conditioning, however, lasted for the normal pressure chamber when using an autoclave or a suitable low vapor permeability. After the cover layers according to the invention, such as driving, a carrier plate, for example one based on acrylic resin, is first used for a very long time, possibly plastic plate with the self-known