CS238209B1 - Non-combustible lightweight asbestos cement element - Google Patents

Abstract

The invention relates to non-combustible lightweight asbestos-cement sheet elements intended for use in the interiors of buildings. The purpose of the invention is to improve the resistance of the elements to dynamic stress. This purpose is achieved by the fact that the dispersion reinforcement, in addition to asbestos and cellulose fibers, also consists of synthetic fibers, polyolefin and/or polyvinyl.

Description

FIELD OF THE INVENTION The present invention relates to non-combustible cellular asbestos-cement sheets for use in building interiors.

Conventional asbestos-cement boards have poor fire resistance, are brittle and poorly machinable. These properties limit their applicability in certain building structures. Due to the fire protection requirements, a fire-resistant, stable asbestos-cement element with increased porosity has been developed, allowing escape of the bound water present at high temperatures without disturbing the material. However, their disadvantage is the relatively high content of asbestos, especially the content of a certain proportion of economically demanding long-fiber asbestos.

It is also known as a non-combustible asbestos-cement board for interior use, especially for sheathing materials of sandwich panels and lightweight partition walls, inner sheathing of perimeter walls, cladding etc. This board maintains good machinability and fire resistance. waste pulp at the same time. the presence of siliceous additives. However, due to the use in building interiors, the material also has to exhibit good impact resistance with suppressed tendency to shrink and crack propagation.

This problem is solved and the above-mentioned requirements are met by a non-combustible lightweight asbestos-cement element according to the invention, whose

consisting of 20-38% by weight of chrysotile asbestos grades 5 to 6 according to ON 72 1760, 2% by weight of waste pulp containing 70%> 99% by weight of fiber, 5% by weight of expanded perlite, 0.1% by weight of polyolefin or vinyl poles of YVV fibers having a length of 5% 4545mm and a diameter of 15? 15O / µm and 30? 72.9% by weight

238 209 Portland cement. The elements may further comprise up to 10% by weight of the returned production waste.

The asbestos dispersion reinforcement, together with less pulp, provides the necessary static strengths of the elements of the invention with a certain material flexibility; the addition of synthetic fibers gives the elements the necessary resistance to dynamic stress. Polypropylene fibers or fibrillated film are particularly suitable for this purpose, and polyethylene fibers can also be used. The presence of expanded perlite as a dispersion-siliceous additive contributes to the formation of a porous structure and improves fire resistance, insulating properties and machinability of the material.

The non-combustible elements according to the invention are prepared, for example, by first preparing an aqueous suspension of asbestos waste pulp and polyolefin fibers in a fiberizing apparatus, into which a corresponding amount of Portland cement and finally expanded perlite and possibly still own production waste are introduced. The suspension obtained is dewatered in a conventional manner on a Iatschek molding apparatus; The boards are dried after 28 days of curing, preferably in a double-sided oven. Surface protection can be done by conventional paints, dispersion spraying and wallpapering.

Cutting and drilling can be done with conventional tools with reinforced tips.

Examples

Example 1

An aqueous suspension is prepared having a concentration of about 12% of the following components:

kg of chrysotile asbestos # 5 15 kg of waste pulp, a.s.

kg of expanded perlite kg of polypropylene fibers length. 15 mm, diameter 50 µm 160 kg cement

The suspension is drained on a sieve dewatering device.

After 28 days of wet deposition, the products showed a bulk density of 820 kg.m, a flexural tensile strength of 9.5 MPa, an impact strength

8.5 k.

Example 2 ^{238 209}

From a suspension of 44 kg chrysotile asbestos # 5 kg chrysotile asbestos # 6 kg waste pulp a.s.

kg of expanded perlite kg of polyvinyl fibers of length 12 mm, diameter 80 µm

115 kg of cement kg of treated waste from element production are prepared in the same manner as in Example 1. After 28 days of wet deposition, the products exhibited a bulk density of 860 kg.m, a bending tensile strength of 8.0 MPa and an impact strength of 7.0 kJm. ^.

Claims (2)

SUBJECT OF THE INVENTION 238 209 1. A non-combustible cellular awbestocement element comprising 20 to 38% by weight of chrysotile asbestos, 2 to 12% by weight of waste pulp and containing 70 to 99% by weight of fiber, 5 to 15% by weight of expanded perlite 0.1 to 5 wt. % of polyolefin and / or polyvinyl fibers having a length of 5 to 45 mm and a diameter of 15 to 150 µm and 30 to 72.9 wt.% of Portland cement. 2. A non-combustible expanded asbestos-cement element according to claim 1, characterized in that it contains up to 10% by weight of treated waste from the production of these elements.