SE415178B - PROCEDURE FOR MANUFACTURING A LIGHT BUILDING MATERIAL - Google Patents

Description

7403501-5 pressing of a mixture consisting of inorganic expanded materials and a curable binder containing in particular phenolic resin and urea resin.

The above object is achieved according to the present invention by a method, which is characterized in that a granulate of expanded vermiculite is sprayed with stirring with the binder present in aqueous solution and that the granulate so sprayed is compressed at room temperature in a pre-pressurized device to a conveyor. press cake, then introduced into the press and finally hot pressed and cured in a known manner. As a combustible resin component in the binder, a phenolic resin is preferably used and / or as a non-combustible, nitrogen-containing resin component in the binder, a urea resin is used, the urea resin component in the binder preferably amounting to 10-25 mol%.

In the event of a fire, a building material produced in this way by the action of heat on the urea resin produces a nitrogen-enriched atmosphere which prevents the combustion of the combustible resin component (phenolic resin) so that no charring occurs, but a so-called carbonation is formed, through which a thick, heat-resistant carbon layer is built up on the surface of the building material body.

In addition to the organic binder, the building material can also contain water glass as an extra binder. The water glass content then amounts to at least 10% by weight, calculated on the total amount of binder.

The water glass additive to the binder acts, among other things, to increase the heat resistance of the manufactured building material.

In a preferred embodiment of the invention, the moisture content of the binder-coated granulate is preferably reduced to below 7%, after which this granulate is preferably pressed in a high-frequency heated press.

In the process of the present invention, the binder-sprayed granulate is pre-compressed and taken out at room temperature, after which it is finally pressed and heat-cured. Due to the pre-compression, the extracted granulate has such a strength that a stable piece of press is formed, which can be inserted into the press without special means of transport, such as sheet metal or strip.

According to a further advantageous embodiment of the method? Lr035Û1-5 according to the present invention, reinforcing and reinforcing elements are introduced during the spraying of the granulate with the binder, after which the granulate is preferably pre-compressed and then pressed to the final building material. Glass fiber, glass wire and the like are particularly well suited as reinforcement and reinforcement elements, respectively.

Building materials produced according to the present invention can be assembled into a multi-layer slab, especially in the platform directly during manufacture. Such a multilayer plate can be produced by pressing the binder-coated granulate and the pre-compressed press cake together with previously binder-coated cover sheets and outer cover plates, respectively. In such a process for producing multilayer plates, when using, for example, paper, glass webs, aluminum foil and the like, an improved mechanical strength of the produced plate is obtained.

If you want to add water glass as an extra binder, the granulate is sprayed with water glass in addition to the spraying with the organic binder in various spraying devices.

It is true that CH patent 187,051 discloses a building material plate which has expanded mica and water glass as binder. However, when using an inorganic binder, such as water glass, a considerably larger binder additive is generally required than when using organic binders.

In addition, when using binders, such as water glass, which on curing emit a relatively large amount of water, difficulties arise in disposing of this water sufficiently quickly, which generally leads to relatively long pressing times. The use of water glass as a binder for building material bodies has therefore been used to a small extent.

When water glass is used together with the other binder, a considerably smaller amount of water glass is required than in the known method according to CH patent no. 187 051, since a larger part of the binder action originates from the organic binder.

As the organic binder content on curing emits only a relatively insignificant amount of water, in the process of the present invention there is a much smaller amount of water to be disposed of, and the process can be carried out with much shorter pressing times than was the case for building materials, which bound only with water glass. 7403501-'5 By means of the separate sprays of the organic binder and the water glass, respectively, on the expanded granular material, an adhesive film is formed on the expanded grains, which contains both the organic binder and the water glass. In this adhesive film a precipitation reaction takes place, whereby the film changes to a gel-like consistency. It turns out that the binder-coated granulate after pre-compression gives a substantially stronger body than a granulate which is bound with the organic binder or the water glass alone.

The following non-limiting examples are provided to further illustrate the present invention.

EXAMPLE 1 In 600 liters (50 kg) of vermiculite having a grain size of 0.5-3 mm were mixed by spraying in a free-falling mixer with 12 liters of a 70% aqueous resin mixture containing 85 mol% of phenol. formaldehyde resin and 15 mol% urea-formaldehyde resin, the expanded mica grains being uniformly moistened.

The resin-moistened granulate thus obtained was uniformly compressed at a pressure of about 1.5 kp / cm 2 to 50% of its original shaking volume in a suitable unheated pre-pressing device, whereby a transportable molded piece was obtained. This piece was finally cured in a press equipped by means of high-frequency heating and / or thermal heating by simultaneous compression of resin-moistened kraft paper cover plates on one side at a pressure of 2-3 kp / cm 2 and a press temperature of 150-17000. The molded piece was taken out in a hot state and cut to the desired size.

When testing the combustibility, no nitrogenous or combustible vapors or gases were detected, and the material began to glow at the prevailing temperature when exposed to flames, and showed no afterburning when the flame was removed.

The building material prepared according to the example had a bulk density of 350-400 kg / m3 and a bending fracture limit of 40-50 kg / cm 2.

EXAMPLE 2 For the preparation of a mixed resin solution, 1 kmol of phenol (94 kg), 0.15 kmol of urea (9 kg) and 1.6 kmol of formaldehyde (120 kg, 40% by weight solution) were catalyzed with sodium hydroxide solution and condensed at 80 DEG-10,000 to a mixed resin. The resin solution was then evaporated by vacuum distillation to contain 70% solids. 7403501-5 600 liters (50 kg) of vermiculite with a grain size of 0.5-3 mm were mixed by spraying in a mixer, which caused free fall, with 12 liters of this 70% mixed resin solution in the same manner as in Example 1.

The resin-moistened granulate was then processed according to Example 1.

EXAMPLE 3,600 liters (50 kg) of vermiculite having a grain size of 0.5-3 mm were sprayed on one side of a free-fall mixing apparatus with 5.4 liters (6.21 kg) of the mixed resin given in Example 2. the solution and in another mixing device with 5.4 liters (8.1 kg kg) of 48-50 ° B soda water-water glass so that the expanded mica grains are uniformly moistened. The granulated thus moistened was uniformly compressed in a suitable unheated pre-pressing device at a pressure of 1.5 kp / cm 2 to 50% of its original shaking volume, whereby a transportable molded piece was obtained. This piece was then cured in a high-frequency heating and / or thermally heated press during simultaneous compression with resin-moistened kraft paper cover plates on one side at a pressure of 2-3 kp / cm 2 and a press temperature of 150-170 ° C. The molded piece was taken out in a hot state and cut to the desired size.

The plate prepared according to the example had a bulk density of 350-400 kg / m 3 and a bending breaking limit of 45-55 kp / cm 3.

EXAMPLE 4 In the preparation of a building material slab, it is carried out in accordance with Example 3 except that 600 liters (50 kg) of vermiculite are used together with only 4.2 liters (4.83 kg) of mixed resin solution, but with a larger share of water glass, ie 6.7 liters (10.05 kg) of soda water glass of the same quality as in Example 1.

The obtained building material body had, in accordance with Example 3, a bulk density of 35o-400 kg / m3 and a bending width limit of 45-55 kp / emz but exhibited a higher fire resistance due to the larger proportion of water glass binder.

Claims (5)

7140350145 PATENT CLAIMS 1. A process for the preparation of a lightweight building material by hot pressing a mixture consisting of inorganic expanded materials and a curable binder containing in particular phenolic resin and urea resin, characterized in that a granulated expanded vermiculite is sprayed with stirring with the binder present in aqueous solution and that the granulate thus sprayed is compressed at room temperature in a pre-press device separated from the press into a transportable press cake, then introduced into the press and finally hot-pressed and cured in a known manner. _ 2. A process according to claim 1, characterized in that the moisture content of the sprayed granulate before hot pressing is reduced to below 7%. 3. A method according to claim 1 or 2, characterized in that the hot pressing is carried out in a press heated by means of high frequency current. 4. A method according to any one of claims 1-3, characterized in that reinforcing or reinforcing elements are introduced into the granulate during the spraying with the binder. 5. A method according to any one of claims 1-4, characterized in that the pre-compressed press cake is pressed with adhesive-moistened cover plates. BEFORE PUBLICATIONS: Sweden 372 249 (C048 43/02) France 1,421,400 United Kingdom 998,187