CS235296B1 - Non-flammable flexible asbestos cement element - Google Patents

Abstract

The invention relates to asbestos-cement elements. The purpose of the invention is to ensure the resistance of the product to dynamic stress, in particular impact load, while maintaining good machinability and flexibility. This purpose is achieved according to the invention in that the dispersion reinforcement is formed by a combination of asbestos fibers, cellulose and synthetic fibers of polyolefin and/or polyvinyl.

Description

The invention relates to a non-combustible flexible asbestos-cement element.

Conventional asbestos-cement elements are mainly used as exterior cladding material * for façades, balconies and other building structures due to their good mechanical strength and weather resistance including frost. Their disadvantages of poor mechanical machinability, brittleness, relatively high bulk density limit their usability as a honeycomb material up to 15 mm thick. In addition, these materials have low fire resistance, which again limits their use. Asbestos cement elements containing silica additives are characterized by increased porosity, good workability and fire resistance. However, because of the high content of asbestos, especially the economically demanding long-fiber asbestos, it is advisable to use this material exclusively for fire protection purposes. Asbestos-cement elements with pulp admixture, which together with asbestos perform the role of dispersion reinforcement, exhibit not only good workability and fire resistance, but

high flexibility and flexibility and are therefore used as a honeycomb material for sandwich building components and lightweight partition walls. However, there is a certain decrease in the initial elasticity of these elements after some time, and moreover, these elements do not satisfy sufficiently where resistance to dynamic stress is required.

These drawbacks are eliminated in the non-combustible flexible asbestos cement element according to the invention, which comprises 4 to 18% by weight of chrysotile asbestos of Classes 5 and / or 6 according to ON 72 1760, furthermore 5 to 15% by weight of kraft pulp. a milling degree of 5 to 40 ° SR and / or waste pulp containing 70 to 99 wt. from 0.1 to 6% by weight of synthetic polyolefin

235,286 and / or polyvinyl fibers having a length of 5 to 40 mm and a diameter of 10 to 150 µm and 61 to 90% by weight of Portland cement.

The combination of asbestos and pulp gives the elements good workability, flexibility and flexibility, especially in the first period after production. Suitable for the purpose. they are polyolefin, preferably polypropylene, fibers, polyvinyl fibers or combinations thereof. Flaked, fibrillated films of these materials may also be used.

The invention will be explained in more detail below and exemplified by embodiments of such an asbestos cement element.

Example 1

An aqueous suspension of 36 kg pulp was prepared. 25 ° SR, absolute dry matter, to which 48 kg of chrysotile asbestos cl. 5 according to ON 72 1760 and 8 kg of polypropylene fibers of 20 mm length and 100 µm diameter. 310 kg of cement were mixed into this suspension.

The suspension obtained was dewatered in a conventional manner on a Hatschek molding machine and allowed to mature for 28 days after compression.

—3

The finished products exhibited a bulk density of 1,600 kg.m, a bending tensile strength of 26 MPa and an impact strength of 10.2 kJ.m

Example 2

An aqueous suspension of 28 kg chrysotile asbestos cl. 5, 28 kg chrysotile asbestos cl. 6, 42 kg of kraft pulp 15 ° SR a.s.

(absolute dry matter), 15 kg of polyvinyl fiber of 15 mm length and 45 µm diameter and 250 kg of cement. From this suspension, the elements were prepared by dewatering and pressing, which after 28 days of wet deposition -3 had a density of 1520 kg.m, bending tensile strength -2

MPa and impact strength 9.1 kJ.m ·

Example 3

In the same manner as in Example 1, a suspension of 38 kg of chrysotile asbestos was prepared. 5, 38 kg waste pulp and * 5 kg polyvinyl fibers of 6 mm length and 20 µm diameter, kg of polypropylene fibers of 18 mm length and 25 µm diameter, 290 kg

235 296 cement and 20 kg treated waste. Elements were prepared from this suspension which, after compression and subsequent 28 days of wet deposition, had a bulk density of 1650 kg.m, a tensile strength of -2 MPa of 22 MPa, and an impact strength of 8.7 kJ.m.

The elements according to the invention are intended especially for interiors of residential, civil, industrial and agricultural buildings, family houses and cottages as casings of light partitions, interior wall cladding and interior casings of peripheral walls. The surface treatment can be done both by common coatings, by dispersion spraying and wallpapering. Cutting and drilling. can be done with conventional tools with reinforced tips.

Claims (2)

SUBJECT OF THE INVENTION 23S 296 Flame-retardant flexible asbestos cementitious composition, characterized in that it contains 4 to 18% by weight of chrysotile asbestos of classes 5 and / or 6 according to ON 72 1760, furthermore 5 to 15% by weight of kraft pulp having a grinding degree of 5 to 40 ° SR and / or waste pulp containing 70 to 99% by weight of fiber fraction, further 0.1 to 6% by weight of synthetic polyolefin and / or polyvinyl fibers having a length of 5 to 40 mm and a diameter of 10 to 150 µm and 61 to 9θ, 9 masses · # Portland cement · 2. The asbestos-cement element according to claim 1, characterized in that it contains up to 15% by weight of the treated waste g.