NL7905316A - PROCESS FOR MANUFACTURING BY PRESSURE FORMING AND HIGH TEMPERATURE OF MOLDED AND REINFORCED PANELS FROM POLYURETHANE FOAM AND THE PANELS SO OBTAINED. - Google Patents

Description

> * 70 8063

Hath Freres, S.A.

Strasbourg-Meinau, France.

Process for manufacturing by pressure and high temperature deformation of molded and reinforced polyurethane foam panels and the panels thus obtained.

The invention relates to the field of the production of molded panels, in particular intended for the manufacture of false ceilings, panels for automobiles and the like and to a method for the production, by deformation under pressure and high temperature of molded and reinforced panels from polyurethane foam.

The invention also relates to the panels thus obtained.

There are now rigid and semi-rigid poly-urethane housings, which have very good thermoplasticity characteristics, so that a plate made of such a foam can be heated for softening, then placed between the plates of a press, equipped with a punch and die device, after which the panel obtained after operation of said press shows permanent shapes as soon as the foam has cooled. The cooling of the foam proceeds quickly due to the fact that it takes place during the compression in the device, the latter being additionally advantageously cooled for this purpose.

These plates converted into molded panels are obtained, either by splitting to the desired thickness of free-foamed blocks, or by laminated foaming between two rolling mats, the thicknesses of the plates being determined by the distance separating the rolling mats.

The polyurethane foam used is a foam with 25 woe components, a first component consisting of: 100 gww parts of a polyether resin, such as that known under the trade name Besnophen 1077A (Bayer company), 0.2-1 parts by weight. of a polyisocyanurate-forming tri-7905316 2 merization activator, such as that known under the trade designation 1026 (Bayer company) and 0.5-2 parts by weight of water and a second component, consisting of: 5 230 parts by weight of methylphenyl diisocyanate, such as that known under the tradename Desmodur 18½ or ^ V 20 (Bayer).

However, the panels obtained by the known method are expensive and have a high weight. To obtain a molded panel of 2 m and a thickness of 8 mm, with sufficient stiffness cm to be self-supporting, e.g. for the manufacture of a ceiling plate for an automotive roof, it is nowadays assumed that a foam plate is used. of a thickness of 0 mm and a density of 80 g / 1. Ha and compressing it to a thickness of 8 mm, such a 2.

2 m panel have a weight of 600 kg, which does not bear a low cost.

The present invention aims to overcome these drawbacks.

Namely, it relates to a method of manufacturing by high-pressure, high-temperature molded and reinforced polyurethane foam panels consisting essentially of providing a thin foam sheet on both surfaces of a stiffening film in which the sheet and / or the films are coated with a fastener, placing the plate with the two films in a desiccant or between two heated plates for 1 - 2 minutes at a temperature of 170 - 220 ° C and then withdrawing the hot assembly obtained at the heat source and immediately placing it within 3-10 seconds and an average of 5 seconds between the plates of a press, provided with a punch and die, compressing the assembly for 30 seconds until it has cooled and finally opening the press and releasing the finished molded panel.

According to an inventive feature, the fastening agent is a heat-reactivable irreversible polyurethane elastomer having two polymerizable components.

According to another feature of the invention, 7905316 3β the heat-reacting agent, after its heat reactivation, serves to smear the stiffening foils over the foam sheet.

In accordance with another feature of the invention, the fastening agent exhibits a polymerization phenomenon after heat liquefaction and continues after molding for 8 hours so that the process becomes irreversible even when the molded panel is exposed to a temperature of 150 ° C.

In accordance with another feature of the invention, the polyurethane eggstomer constituting the fastener preferably has the following composition:

Component 1: 100 parts by weight of a component, the polyurethane resin, such as that known under the trade name Desmocoll (company 3ayer) or under the trade name. Witcobond 52U0 (Witco company).

Component 2: 5-10 wt. parts of a curing isocyanate, such as that known under the tradename Witco XB (firm Witco).

The invention also relates to a new industrial product on a molded panel, obtained by applying the above-described method and mainly consisting of a thin plant polyurethane foam and two stiffening foils, glued on both surfaces of the plate by means of a fastening agent in in the form of an irreversible polyurethane eggstomer.

The invention will be better understood with reference to the preferred embodiment given below as an example, which is further elucidated with reference to the drawing, in which: figures 1 - 3 show different phases of the method according to the invention and figure k shows a is section of a panel according to the invention.

A polyurethane foam sheet and two stiffening foils are pre-coated with an irreversible two-component plastic / urethane elastomer. For this purpose, the two components are mixed in a vessel, which vessel is connected to a spray gun, with which the mixture of polyurethane elastomer laser can be sprayed onto the plate and / or the stiffening foils. The mixture dries in two or three hours 79053 16 cr k at ambient temperature or in a few minutes in case of drying with hot air, infrared radiation or the like, in a drying oven.

As shown in figure 1, a sandwich is then formed by providing the foam sheet 1 on both surfaces with the two films 52 and then the assembly is placed between two heating plates 3 or in a drying oven, these plates having the temperature of 170 - 220 ° C. After a heating time of 1-2 minutes, the foam softens and the elastomeric coating becomes liquid, the polymerization then being started by the heat. The hot assembly thus obtained is taken out of the plates or the drying oven and immediately placed between the plates of a press, provided with a punch U and a die 5, ie in a period of time between 3 and 10 seconds and an average of 5 seconds, before it. molding by pressing (Figure 2). The press is then closed, and in the course of deforming the sheet by pressing, the stiffening foils slide over the surfaces of the foam without tearing under gluing without stress against all shapes, thanks to the lubricating effect originating from the liquefied polyurethane- elastomer (Figure 3). The assembly is maintained under pressure between the plates of the press for 30 seconds, which correspond to the cooling time »thanks to a circulation of cold water inside the punch b and the die 5 · Ha this cooling is opened and the mold panel 6 has been removed, the shapes of which have become permanent and which has a high rigidity due to the strong adhesion of the stiffening foils to the foam, the elastomer being hardened on passing from the role of lubricant to that of fastener.

After this removal of the panel 6 from the press, the chemical polymerization process continues for a further 8 hours and is then completed, the process then becoming irreversible, so that even if the panel is subjected to a temperature of 150 ° C elastomer does not liquefy.

The stiffening foils 2 consist of paper, in particular kraft paper, a glass fiber fleece, a non-woven fiber, a fabric, a laminated material or the like.

7905316 5 \

The rigidity of the formed panel 6 is obtained thanks to the films 2, which are glued to the plate 1 during molding. In molding, the irreversible polyurethane elastomer liquefied by the heating allows the film 2 to slide over the surfaces of the plate during pressing, so that both films 2 follow the relief changes of the foam, which are pressed by the pressing member against the molds, without tearing or subsequent parasitic stress.

Thanks to the invention it is thus possible, for example, to manufacture a self-supporting 2 m shaped panel with a weight of 1500 kg, starting from a cover plate of 15 mm thickness and a density of 50 g / l.

7905316

Claims (5)

Method for manufacturing by pressure and high-temperature deformation of molded and reinforced polyurethane foam panels, characterized in that a thin foam plate is provided on its two surfaces with a stiffening foil, wherein the plate and / or the films are coated with a fastening agent, the plate with the two films is placed in a drying oven or between two heating plates for 1 - 2 minutes at a temperature of 1 TO - 220 ° C, then the resulting hot assembly is withdrawn from the heating source and immediately place it in a 10 time period between 3 and 10 seconds and on average 5 seconds between the plates of a press, provided with a punch and a die, press the assembly for 30 seconds until it is cooled and finally open the press and finally formed panel unloads. A method according to claim 1, characterized in that the fastening agent is an irreversible polyurethane elastomer which is heat activatable and has two polymerizable components. 3. A method according to claims 1 - 2, characterized in that the fastening agent, after its heat reactivation, serves to spread the stiffening foils over the foam plate and then, after cooling, as the fastening agent. U. Process according to claims 1 to 3, characterized in that the fastening agent is an elastomer which is polymer honors, after liquefaction, by heating, said polymerization continuing after molding for 1 * 8 hours, so that the process becomes irreversible even when the molded panel is subjected to temperatures of 150 ° C. 5. A method according to claims 1 - characterized in that the irreversible fastening agent preferably has the following composition: component 1: 100 parts by weight of a one-component poly-7905316 τ Ί. urethane resin, such as that known under the trade name Desmocoll (Bayer company) or under the trade name Witcobond 52 ^ 0 (Witco company); component 2: 5-10 avg. Din ran a curing isocyanate, such as that known under the tradename Witco XB (Witco Company). Shaped panel obtained by using the method according to claim 1, characterized in that it mainly consists of a thin sheet of polyurethane foam and two stiffening foils, adhered to both surfaces of the sheet by means of a fastening agent in the form of an irreversible polyure-10 thane elastomer. 7905316