DE1025319B - Process for the production of mixtures of fibrous materials and setting or setting binders - Google Patents

Description

Process for the production of mixtures of fibers and hardening substances respectively. setting binders in the manufacture of mixtures of fibrous materials and hardening or setting binders, it is noticeable unpleasantly d.ass both for the individual substances and in the mixtures filled with air Voids are present, which the strength and other properties, such as z. B. the tightness of the materials or workpieces made from these mixtures affect unfavorably.

For example, it is known that, inter alia, in asbestos-cement mixtures a certain porosity usually cannot be avoided. This is because the cavities between the individual fibers or that between the capillary pore volume containing fibers that are not or not completely disrupted by the binder, e.g. B. cement paste or plastic, not completely filled will. Small and very small voids can also be found in the binders or fillers persist, especially when the surface of their particles with a so-called occluded air skin surrounds or is water-repellent in itself or if it has too little adhesiveness.

There then remain more or less pronounced ones filled with air Separating layers or bubbles in the material mixtures. or in service from these Mixtures manufactured workpieces exist that the tightness and the homogeneity the same disturb and have a strength-reducing effect.

It is already known to improve the strength of plaster of paris by that the plaster of paris is subjected to the action of a vacuum when mixed with water as a gypsum slurry will. Furthermore, it has already been suggested that the freshly clad concrete should be used To withdraw part of the water by means of a vacuum pump; this makes it possible, however, especially with larger cross sections of the workpieces, not those in these in finest distribution contained air pores, because of the toughness the mass of the volume resistance for the air bubbles is much too great.

Also is a method of making deflated fiber cement known, in which the mixed material is prepared and ventilated under negative pressure is compressed in a second working space, which is also under negative pressure.

Very particularly favorable results are now achieved according to the invention achieves a two-step process which consists in; that both the fibers, z. B. asbestos, artificial mineral fibers such as glass wool, slag wool. Synthetic fibers or vegetable fibers, which are in a dry or moistened state can be located, as well as the binders each for themselves initially in appropriate Vacuum vessels are freed from the trapped or adhering air, whereupon these substances are then mixed with one another in a vacuum and the mixture is converted into corresponding Forms transferred and atmospheric or for the purpose of further compression an overpressure is exposed.

It is also already known when impregnating absorbent Sheets or workpieces made of paper, wood, ash or the like before application of the impregnation agent under vacuum to ensure better adhesion of the To effect impregnation agent.

In the present case, on the other hand, it is about production of mixtures of fibers and binders that make up a homogeneous density Mass for the production of workpieces should arise.

The inventive treatment of both the fibrous materials in a vacuum the air is sucked out of the cavities of the fibers and between the fibers, as also by treating the binder, for example cement or else of plastics, this is also completely freed of air; there too Mixing of the substances with one another, for example in an agitator vessel under vacuum takes place, no air-filled cavities can therefore be found in the substance mixtures remain.

If you now set the contents of the mixing vessel to the atmospheric or the binder, especially its thinnest, is also exposed to a higher pressure Divide, if this has not yet been done by mixing completely between the fibers and all pores should have penetrated, now in all of them existing airless cavities pressed into it. Thus, by the invention Process to produce materials and workpieces from completely pore-free mixtures, compared to the previously known products due to their tightness and homogeneity also have increased strength properties.

There is a particularly favorable embodiment of the new method in that the fibrous materials freed from the air in a vacuum initially with be mixed with a very low viscosity binder, whereupon this mixture in vacuo or under atmospheric pressure further binders in thin, viscous, paste-like: r or in dry form will.

Claims (2)

PATENT TANSPRCCIIE. 1. Process for the preparation of mixtures of fibrous materials, e.g. B. asbestos, artificial mineral fibers such as glass wool, slag wool, synthetic fibers or vegetable fibers, or from mixtures of the same and hardening or setting binders such as cement, plastics, the material being vented under negative pressure, characterized in that the fibers and also the binders are each freed from the enclosed or adhering air in appropriate vacuum vessels, then mixed with one another in a vacuum and then exposed to atmospheric or overpressure. 2. The method according to claim 1, characterized in that that the fibrous materials freed from the air in a vacuum initially with a be mixed in a very thin liquid state, whereupon this Mixing in vacuum or under atmospheric pressure further binders in thinner or thicker or paste-like or also in dry Form can be mixed. Publications considered: German patent specification No. 722,372; Tonindustrie-Zeitung, 1955, pp. 107 to 109.