NO146501B - PROCEDURE FOR MANUFACTURING A LIGHT, NON-FLAMMABLE BUILDING MATERIAL - Google Patents

Description

The present invention relates to a method for the production of a light, especially flat, non-

combustible building material with good heat-insulating properties

created by hot pressing a mixture of inorganic expansion materials and a hardenable binder, especially containing phenol resin and urea resin, and the peculiarity of the method according to the invention is that a granule of expanded vermiculite, while stirring,

sprayed with the binder present in aqueous solution

agent, the thus bonded granulate is pre-compressed at room temperature in a pre-compression device separated from the press into a transportable press cake which is then introduced into the press and finally hot-pressed and cured in a manner known per se.

These and other features of the invention appear in the patent claims.

Non-combustible building material bodies are usually composed of inorganic materials. For example, it is achieved by

mixture of expansion materials, such as expansion mica (vermiculite), with plaster or cement and a suitable shaping after curing, shaped bodies such as e.g. slabs or blocks, which can be used as light building elements. The relatively large addition of cementing agents which are necessary for a sufficiently strong bond of the expansion materials usually lead to relatively long curing times or bodies that have little thermal insulation capacity. Furthermore, building material bodies of this type are mostly difficult to process or only during severe material wear.

From Swiss patent document no. 519,639 it is known to

mix vermiculite and an inorganic, non-combustible binder in a volume ratio of 9:1 and then press the mixture into building material bodies. The necessary addition of binders is also relatively high in this method. The purpose of the present invention is a method which makes it possible to obtain building material bodies, in particular

building material boards that contain a resin-bound inorganic expansion material, possibly with added smaller amounts of mineral wool, fly ash, or the like whereby, by adding hardenable organic binders, it is only necessary to use a very small binder addition, and despite the use of this organic binder, a non-combustible building material

body with good heat-insulating properties, which is also good sound-insulating.

In particular, a resin mixture or mixed resin is used in the binder, with at least one combustible resin component and at least one non-combustible, nitrogen-containing resin component. The combustible resin component is then a phenolic resin and

the non-combustible, nitrogen-containing resin component is then a urea resin. The content of the urea resin component in the resin mixture or mixed resin is advantageously between 10 and 25 mole percent.

In the event of a fire, due to the heat effect on the urea resin, an atmosphere enriched with nitrogen occurs in such building material bodies, which thereby prevents combustion of the combustible resin component (phenolic resin) to such an extent that no charring takes place, but instead a so-called mineralization, whereby a thick, thermally stable carbon layer forms on the surface of the bodies. As expansion materials, vermiculite has been shown to have the necessary good properties, in that, unlike, for example, expanded perlite, it retains its crystalline nature during expansion, which enables the formation of a durable press cake.

According to an advantageous embodiment of the invention, the building material body can, next to the organic binder, also contain water glass as a binder, for example in amounts which, calculated on the total amount of binder, calculated as solids, amount to 10 percent by weight or more. The addition of water glass to the binder causes, among other things, an increase in the fire resistance of the obtained building material bodies.

When carrying out the method according to the invention, a granule of expanded vermiculite is sprayed with the binder present in aqueous solution while stirring, whereby, on the basis of the vermiculite and calculated as a solid, 2 to 30 percent by weight of resin is taken up and the granules thus coated are pressed in hydraulic, heated presses for moldings. Preferably, the moisture content in the coated granules is reduced to below 1% and then these coated granules are pressed in a special press, preferably a press that is heated using high frequency.

When carrying out the present method becomes

the coated granules, at room temperature, pre-compressed, removed from the mold and then pressed and thermally cured. The granules from the mold have as as a result of the pre-compression such firmness that it forms a stable press cake which can be fed into the press without special means of transport such as transport plates or conveyor belts.

According to an advantageous embodiment, it is introduced during the spraying of the granulates with binder reinforcement-resp. reinforcing elements, after which the granulate is pre-compressed and then pressed into the final shape of the building material bodies. The present building material bodies can be directly integrated, especially in the form of plates, to produce a multi-layer plate. Such a multi-layer plate can, according to an advantageous embodiment, be produced by the coated granules or the pre-compressed press cake is hot-pressed together with previously binder-coated cover plates or together with external cover plates. With such a multi-layer structure, e.g. using paper, glass-fibre wool, aluminum foil etc. an increase in the mechanical strength of the manufactured plate.

You can also proceed so that the coated granules containing an expansion material are first pre-compressed and shaped respectively. pressed in hydraulically heated presses into shaped bodies by spraying the granulate next to the spraying with the organic binder unless

quantities of water glasses over separate spray devices.

From the past it is known a building material plate which

consists of vermiculite with water glass as binder.

When using an inorganic binder such as water glass

however, a significantly higher binder addition is usually required than when using organic binders. Furthermore, the use of binders such as water glasses, which release a relatively large amount of water during curing, the difficulty that this amount of water must

is removed sufficiently quickly, which usually leads to relatively long pressing times. The use of water glass as a binder for building material bodies has therefore had little spread.

In the present method, if the adjacent

an organic binder is also used in smaller amounts of water glass, a significantly smaller amount of water glass is required than in the previously known methods, because the majority of the binding agent effect comes from the organic binder. Since the organic binder portion only emits a relatively small amount of water during curing, with the present method significantly smaller amounts of water must be carried away and this leads to significantly shorter heat treatment times than would be the case for building material bodies connected only with water glass.

By a separate spraying of the organic binder or water glass on the expansion material granules, a binder film is formed on the expanded grains, and this film contains both the organic binder and water glass. A precipitation reaction then takes place in this binder film, whereby the film turns into a gel-like consistency. It has now

it has been shown that such coated granules, after pre-compression, give raw blank bodies with significantly greater strength than those obtained by a coating with an organic binder, resp. with a glass of water alone.

The following examples further illustrate the invention.

Example 1

600 liters (50 kg) of vermiculite with a grain size from 0.5

to 3 mm is mixed by spraying in a free-fall mixing device with 12 liters of 10% aqueous resin mixture, consisting of 85 mole percent phenol formaldehyde resin and 15 mole percent urea formaldehyde resin, so that the grains of the expanded vermiculite are moistened evenly throughout. The resin-coated granules produced in this way are uniformly compressed in a suitable non-heated prepress device at a pressure of approx. 1.5 kp/. cm 2 to 50% of the original volume, whereby a small transportable compact is obtained. This is then cured in a press equipped with high frequency and/or ter-

mis heating and during simultaneous compression with tire

sheets of kraft paper coated with resin on one side, at a pressure of 2 to 3 kp/cm 2 and press temperature from 150 to 170°C. The pressed object is removed hot from the mold and cut to the desired format.

When tested for flammability, no suffocating or flammable vapors or gases occurred, and the material glowed under the influence of flame depending on the prevailing temperature. After removing the flame, no afterburn was visible.

The building material produced had a specific weight of 350 to 400 kg/m 3 and a bending strength of 40 to 50 kg/cm 2.

Example 2

To prepare a mixed resin solution, one kmol of phenol (94 kg), 0.15 kmol of urea (9 kg) and 1.6 kmol of formaldehyde (120 kg) are catalyzed as a 40% by weight solution with caustic soda and the mixture is condensed at 80 to 100°C to a mixed resin. The resin solution is then evaporated by vacuum distillation

to 70% solids content.

600 liters (50 kg) of vermiculite with a grain size from 0.5 to 3

mm is mixed by spraying in a free-fall mixing device with 12 liters of this 10% mixed resin solution in the same way as in example 1.

The granules thus formed with a resin coating further

is now processed in the same way as described in example 1.

Example 3

600 liters (50 kg) of vermiculite with a grain size from 0.5

to 3 mm is sprayed in a free-fall mixing device on one side with 5.4 1 (6.21 kg) of the mixed resin solution prepared in Example 2 and over a separate spraying device with 5.4 1 (8.10 kg) of sodium hydroxide water glass at 48 to 50°C, so that the grains of the expanded vermiculite are moistened evenly throughout. The granules coated in this way are uniformly compressed in a suitable non-heated pre-press device at a pressure of 1.5 kg/cm 2 to 50% of the original volume, whereby a small transportable press-

body. This is then cured in a press equipped with high frequency and/or thermal heating during simultaneous compression with pressure plates of kraft paper, which is coated on one side with resin, at a pressure of 2 to 3

kg/cm 2 and a pressing temperature from 150 to 170 C. Pressing

the body is removed while still warm from the mold and cut to the desired format.

The produced plate-shaped building material bodies have a specific weight of 350 to 400 kg/m 3 and a bending strength of 45 to 55 kp/cm 2.

Example 4

When producing a plate-shaped building material body be-

the same procedure as in example 3 is used, but with the difference that 600 1 (50 kg) of vermiculite is now only mixed with 4.2 1 (4.83 kg) of mixed resin solution, but with a larger proportion of water glass, namely with 6, 7 1 (10.05 kg) sodium hydroxide water glasses, of the same quality as used in example 1.

The building material body obtained had, as in example 3, a specific weight of 350 to 400 kg/m^ and a flexural strength of 45 to 55 kp/cm 3 , but due to the greater proportion of water glass in relation to organic binder, the bodies showed greater fire resistance.

Claims (5)

1. Process for the production of a light, especially board-shaped, non-combustible building material with good heat-insulating properties by hot pressing a mixture of inorganic expansion materials and a hardenable binder, especially containing phenolic resin and urea resin, characterized in that a granule of expanded vermiculite is sprayed with the binding agent present in an aqueous solution while stirring, the thus bonded granule is pre-compressed at room temperature in a pre-press device separated from the press into a transportable press cake which is then introduced into the press and finally hot-pressed and cured on and off known way. 2. Method as stated in claim 1, characterized in that the moisture content in the glued granules is reduced to below 1% before the hot pressing. 3. Method as stated in claim 1 or 2, characterized in that the hot pressing takes place in a press heated by means of high-frequency current. 4. Method as stated in claims 1-3, characterized in that during the spraying of the granulate with the synthetic resin mixture, reinforcement or reinforcement elements are introduced into it. 5. Method as stated in claims 1-4; characterized in that the pre-compressed press cake is hot-pressed together with previously binder-coated cover plates.