DK149882B - PROCEDURE FOR THE MANUFACTURE OF AUTOCLAVATED FIBER PREPARED PRODUCTS - Google Patents

Description

149882 i

The present invention relates to a process for the production of autoclaved fiber-reinforced moldings having a weight of at least 600 kg / m and having a matrix of cured calcium silicate binder, which first produces an aqueous slurry of fibers, of which at least 5% by weight cellulose fibers , calculated on the total dry matter content, silica, lime and / or calcareous material, and optionally plasticizers in the form of colloidal silica and / or clay particles 10 and other additives containing more water than necessary to cure the calcium silicate binder on which green molds are produced. by dewatering the slurry, after which the green moldings are autoclaved, after any prior pressing and curing.

By "lime" is meant CaO and / or CaiOH ^. "Calcareous material" means material containing lime as well as material which emits lime in the presence of water, such as cement, e.g. By "autoclaving" 20 is meant heat treatment in the presence of saturated water vapor at superatmospheric pressure.

Fiber-reinforced moldings with a matrix of cured calcium silicate binder comprise a large product group, to which i. For example, 25 autoclaved products prepared by the method referred to in the introduction, hereinafter referred to as "type 1 products", include unautoclaved products prepared by the same process, except that the green moldings are cured at atmospheric pressure and temperatures between ca. 20 and 100 ° C, hereinafter referred to as "type 2 products", as well as 1,9882 2 autoclaved lightweight products having a basis weight of less than 3 3 to 600 kg / m, typically 150 to 320 kg / m, hereinafter referred to as "products of type 3 ".

Typically, the lightweight products (type 3) are prepared by a process which first prepares an aqueous slurry of crystalline or amorphous silica.

CaO or CafOH ^ / fibers and possibly other additives containing more water than necessary to cure the calcium-silicate binder, after which silica and lime in this slurry, when left standing and most often under heating by a "pre-reaction," are dissolved and reacted with an aqueous fiber-containing calcium silicate gel, which then may be added. more or less dewatered into green moldings, which are then autoclaved for lightweight products.

Such methods for making lightweight products are known, for example, from EP Patent No. 7,585, U.S. Patent No. 3,902,913 and EP Patent Application No. 64,916.

Due to their porous nature, these lightweight products have very poor strength properties, eg typical bending tensile strengths of 0.8 - 1.2 MPa, but due to their porosity and good heat resistance found widespread use as thermal insulation materials.

The autoclaved and non-autoclaved products with room weights of at least 600 kg / m, ie. the type 1 and 2 products have far better strength properties, typical bending tensile strengths are at least 8 MPa, e.g. 8-16 MPa, so that they are suitable as building materials, for example in the form of flat or corrugated sheets and panels 30 for use as, for example, roofing and interior and exterior cladding of buildings.

Numerous variants of the above mentioned process are known for the preparation of type 2 products, ie. non-autoclaved products: U.S. Patent No. 4,261,754 relates to, for example, the manufacture of building materials reinforced with special polyolefin fibers 5 and possibly cellulose fibers to which, if desired, an inorganic fine-grained filler may be added, e.g. to provide greater plasticity and better fiber dispersion during the preparation of the green sheets.

Typical bending tensile strengths for such unautoclaved polyolefin reinforced sheets are approx. 6 MPa.

DK patent application no. 4926/78 relates to an improved solution of the problem of providing a good fiber dispersion, which is obtained by violent mechanical processing of the fibrous slurry before its dewatering.

Here, the use of fine filler material, such as ultrafine silica dust, hereinafter referred to as "UFS", with a specific surface area of 5-200 m / g and an average particle diameter less than about 100 mm is discussed. 0.5 µm dosed in an amount of up to 10%, typically 2-5%, especially 3.5%, in connection with the preparation of non-autoclaved fiber reinforced sheets exhibiting a typical bending tensile strength of approx. 10 MPa.

Later, it was found that this violent treatment could be avoided if colloidal hydrophilic particles were used as dispersants in the preparation of the initially prepared aqueous fiber slurry, for example special colloidal silica and / or clay particles such as Aerosil 200 and Ludox HS40, in amounts of approx. 2%. Typical cellulose fiber dosages are 2-3%, 30 typical binders of Portland cement and Puzzolan cements, eg containing up to 12% of the UFS mentioned above as Puzzolan. This technique is described in European Patent Application No. 47,158, but exclusively in connection with U9882 4 in the manufacture of non-autoclaved plate products. This provides products with significantly improved strength properties, eg typical bending tensile strengths of 12-18 MPa at room weights of approx. 1600 kg / m.

5 Addition of colloidal silica and / or clay plasticizers, such as Cabosil or benzonite, in amounts of 5-10% by weight in the production of both high-weight uncoated and autoclaved sheets containing at least 5% by weight of cellulose fibers 10 is known from GB Patent Application No. 2,045,306. A typical recipe for flat sheets is, for example, 84.5 wt% Portland cement, 10.9 wt% cotton fiber, 0.5 wt% nylon and 5, 0% by weight of colloidal silica plasticizer which leads to products with a bending tensile strength 3 15 of approx. 19.5 MPa at a room weight of approx. 1450 kg / m.

The use of the above-mentioned UFS as a puzzolan in the production of unautoclaved plates is also known from GB patent application 2 048 330 and EP patent application 68 742, the latter of which relates to the preparation 20 of, for example, flat or corrugated, preferably pressed, cellulose fiber reinforced sheets. sheets, typically having the following composition: 8 wt.% cotton fiber, 67 wt.% Portland cement and 25 wt.% UFS. After curing for 24 hours at 80 ° C and 2 weeks at room temperature, pressed products with 25 bending strengths of approx. 16 MPa at a room weight of approx.

1500 kg / m3.

Finally, numerous variants are known of the method of manufacture of type 1 products initially stated, i.e. autoclaved products. 1

A characteristic feature of these processes is that the aqueous slurry contains three main components: a fiber component, a lime component and an acidic silica component, the acidic nature of which is usually first established under the reaction conditions prevailing during autoclaving. Furthermore, various additives can be used, including plasticizers, for example in the form of colloidal silica and / or clay particles such as Cabosil, Ludox and bentonite. As a lime component, it is known to use portland cement, hydrate lime and mixtures thereof. As an acid silica component that reacts with the lime component during the autoclaving to form calcium silicate hydrates, it is known to use 10 milled quartz, silica sand, diatomite and / or fly ash.

The products thus produced (type 1) differ among others. from the Type 3 products by having a 2 to 10 times the bulk weight and bending tensile strengths greater than 4 MPa, typically greater than 8 MPa, making them 15 suitable for use as roofing and cladding boards.

A significant difference between the type 1 and type 2 products consists in the diverse chemical and crystalline nature of the cured binder. While the unautoclaved, 20 cured binders mainly consist of amorphous calcium silicate hydrates with quite varying stoichiometry containing free lime, the autoclaved products mainly consist of semi-, usually very fine crystalline, tobermorite-like structures with less varying 25 stoichiometry, practically free. Among other things. Thanks to the more crystalline nature of the matrices, the autoclaved products usually distinguish themselves by better weather resistance, less moisture movement and less moisture permeability than the non-autoclaved products. For many 30 years, work has been done on the development of improved type 1 products. because the chemical and morphological structure of the matrices depends on the nature of the starting materials and the reaction conditions before and during the autoclaving in a very complicated and opaque manner.

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A typical result of this development work is described in U.S. Patent No. 3,501,323, which discloses a typical blend of 15 wt% asbestos fibers, 51 wt% Portland cement (as calcareous material) and 34 wt% ground 5 sand ( such as silica). This mixture is slurried in water, after which plates are prepared by dewatering. These plates are pressed and autoclaved, typically for 8 hours at 170 ° C.

Corresponding conventional methods employing hydrate lime, portland cement or mixtures thereof as lime and / or calcareous material; ground quartz, silica sand, diatomite or fly ash, typically with a specific surface area in the range 1000-12000 cm2 / g, especially in the range 3000-5000 cm2 / g, and fibers of asbestos, silica, glass, cellulose and / or organic polymers are also disclosed in U.S. Patent No. 3,501,323.

A process of the same kind for the manufacture of asbestos-free products using, for example, 12% by weight 20 cellulose fibers, 15% by weight Portland cement, 31.8% by weight of lime, 29.2% by weight of ground quartz and 12% by weight -% mica, is disclosed in U.S. Patent No. 4,011,335. This 3 product typically has a weight of 750 kg / m and a bending tensile strength of 13.5 MPa. 1 2 3 4 5 6

Autoclaved products of this kind are also described 2 on page 5 of the description of DK patent application no.

3 3679/80, for example, containing 3 wt% cellulose fibers, 4 9 wt% hydrate lime, 40 wt% fly ash, approx. 30 wt% 5 Portland cement, 12 wt% Wollastonite crystals and 5 6 wt% dispersant in the form of clay sludge. This product has a space weight of approx. 1300 kg / m3 and a bending tensile strength of approx. 7 MPa.

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Furthermore, cellulose fiber reinforced products of type 1 are disclosed in the following writings: GB patent no. 1 421 556, which discloses the manufacture of autoclaved products, for example from crude mixtures 5 with the recipe 36.2% Portland cement, 39.1% diatomite, 5 % cellulose fibers, 12.2% glass fibers and 7.5% perlite with a bending tensile strength of 4.7 MPa at a room weight of 640 kg / m3.

U.S. Patent No. 4,040,851, which discloses the manufacture of autoclaved products, for example, from crude blends with the 50.1% Portland cement recipe, 18.6% diatomite, 6.2% cellulose fibers, and various additives with a bending tensile strength of approx. 9 MPa at a room weight of 930 kg / m3 and a similar product with ground quartz instead of diatomite with a bending tensile strength of approx. 21 MPa at 3 15 a room weight of 1600 kg / m.

U.S. Patent No. 4,132,555, which discloses the manufacture of autoclaved products, for example, from raw blends with the recipe 10% Portland cement, 42% hydrate lime, 38% milled quartz and 10% cellulose fibers with a bending tensile strength of 10.6 MPa at a room weight of 755 kg / m.

Finally, the use of plasticizers in the form of colloidal silica and / or clay particles such as Cabosil,

Gasil, Neosyl and bentonite, as mentioned earlier also in connection with the manufacture of 25 type 1 products, for example from GB patent application 2,045,306, which for example discloses the production of autoclaved products from raw blends with the prescription 41% Portland cement, 44% ground quartz, 4% cotton cellulose fibers, 2% other fibers and 9% bentonite with a bending tensile strength of 30.5 MPa at a room weight of 1400 kg / m and 46% hydrate lime, 41.5% ground quartz, 4% cellulose fibers, 5.5% other fibers and 3% bentonite with a bending tensile strength 3 of 16.5 MPa at a room weight of 1350 kg / m.

A similar process using 40-60% by weight of cement, 30-40% by weight of ground quartz and 5-15% by weight cellulose fibers, and optionally plasticizers of the same kind, for example colloidal silica, which can partially replace quartz, so that, for example, work with approx. 25 wt.% Of quartz and 10 wt.% Of colloidal silica dispersant is also known from the specification 10 of EP patent application No. 68,741. 1550 kg / m and bending tensile strengths of 16-18 MPa.

The object of the invention is to provide a method of the kind mentioned initially, leading to products such as planar or corrugated panels or panels for use as roofing and interior and exterior cladding of buildings and as interior building elements in ships. , with a particularly high strength, low permeability, 20 high frost resistance and high flexibility.

It has now surprisingly been found that this problem can be solved by a process for the production of autoclaved fiber-reinforced moldings having a weight of at least 600 kg / m and having a matrix of cured calcium silicate binder which first produces an aqueous slurry of fibers, of which at least 5% by weight cellulose fibers, calculated on the total solids content, silica, lime and / or calcareous material, and optionally plasticizers in the form of colloidal silica and / or clay particles and other additives containing more water than necessary for curing of the calcium silicate binder, upon which green molds are produced by dewatering the slurry, after which the green mold 9 is autoclaved; after pressing and curing, the process being characterized in that the aqueous slurry, calculated on a dry weight basis, contains 5 to 30%, preferably 8 to 20%, especially 12 to 16%, preferably at least 8% of cellulose fibers; 15-50%, preferably 18-35%, especially 18-25% of silica in the form of ultrafine silica dust with a specific surface area of 5-200 m / g, and an average particle diameter 2Q less than approx. 0.5 µm; 20-80%, preferably 30-70%, especially 45-65% lime and / or calcareous material; as well as 0-40% additives.

The 25 articles made by the method according to the invention are characterized by extremely high strengths in relation to the room weight. The reason for this is probably partly due to the unusually high proportion of cellulose fibers - partly because the novel use of the ultrafine silica dust as acid silica component in 2q production of autoclaved products leads to an unusually high reactivity of the starting material and also to a very close packing of this in the green plates.

Hereby a matrix is obtained in the autoclaved product which is unusually compact compared to that obtained in the prior art, where coarser silica such as diatomite or ground quartz has always been used.

The high reactivity of the starting material also allows for low temperature autoclaving to be carried out, if desired.

3Q The use of fairly high fiber concentrations, at least 5%, preferably at least 8%, is essential for providing reasonable filtration conditions and high homogeneity of the green moldings, which is a necessary prerequisite for a satisfactory final product.

149882 ίο

Thus, by the method of the invention, flat sheets with bending tensile strengths, more specifically BT-max (defined below) of 20-60 MPa at 5 room weights of 900-1600 kg / m 2 can be produced, typically with bending tensile strengths of 30-35 MPa at room weights of 1200-1450 kg / m 2.

Speaking as fibers, there are preferably synthetic inorganic fibers, such as mineral wool, glass, carbon and steel fibers; synthetic organic fibers such as polyester, polyvinyl, polyvinyl alcohol, polyethylene, polypropylene, polyacrylonitrile and polyacrylamide fibers; and / or natural organic fibers, such as cellulose fibers.

As mentioned above, the aqueous slurry must contain at least 5%, especially at least 8%, cellulose fibers, calculated on a dry weight basis. Speaking as cellulose fibers, wood fibers in particular come from, for example, birch, pine and spruce; seed and fruit hair fibers from, for example, coconut and cotton; and leaf and / or bast fibers from, for example, sisal, abaca, flax, hemp and jute.

The fibers serve partly as reinforcement of the autoclaved product and partly as a filtering and retention aid for dewatering.

Particularly satisfactory filtration and retention is achieved by at least a portion of the cellulose fibers being ground to a fineness of 20-60 ° Shopper Riegler and / or by the fibers comprising high fibrillated polyethylene or polypropylene fibers.

According to a preferred embodiment, only cellulose fibers are used as fibers.

A particularly preferred embodiment is characterized in that the aqueous slurry, calculated on a dry weight basis, contains 8-20%, preferably 12-16% cellulose fibers, of which up to half is ground to a fineness of 20-60 ° Shopper. Riegler, preferably 35-50 ° Shopper Riegler.

5 In the case of ultra-fine silica dust, especially fine filter dust comes from electrothermal production of silicon or ferrosilicon with a specific surface area of approx.

25 m / g and an average particle diameter of approx. 0.1 µm.

Speaking as lime and / or calcareous material, 10 especially hydrate lime, hydraulic cement such as Portland cement, for example Type I-V, according to ASTM standard C 150, and mixtures thereof.

Speaking as additives come fillers such as mica, vermiculite, perlite, expanded clay, diatomite and ground 15 quartz, silica sand and fly ash; dyes; waterproofing agents; deburring and curing accelerators such as calcium chloride and aluminum sulfate; flocculants or dispersants; filtration aids such as needle-shaped crystals of Wollastonite; and organic or inorganic plasticizers and fiber dispersants, such as hydrophilic inorganic particles, e.g. colloidal silica particles and refined or unrefined colloidal clay particles.

The autoclaving takes place at temperatures between 100 and 25 240 ° C, especially in the range 130-190 ° C.

The preparation of the aqueous slurry can be carried out in a manner known per se by pulping and slurrying of the fibers in water, after which the other materials are added and optionally added while adding 30 more water to a suitable water / dry matter content.

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However, in slurrying cellulose fibers, it has proved particularly advantageous to first disperse the ultrafine silica in water having a pH greater than 8, then slurry the fibers in this aqueous silica dispersion and finally mix the other materials and, if necessary, more water. . This ensures a particularly homogeneous slurry of the fibers with diminished tendency to clump formation, presumably because the ultrafine silica dust in the basic environment binds to the surface of the individual cellulose fibers, thereby increasing the dispersibility of the cellulose fibers 10.

The preparation of the green mold objects by dewatering the slurry is carried out in a manner known per se, for example by using the Hatschek, Magnani, Head Box, injection or Fourdrinier method.

The green moldings can be designed as, for example, beams, blocks, pipes and planes, or corrugated sheets and panels which, if desired, are pressed, typically together. 2 pressures of 10-100 kp / cm, and hardening, typically for 6-24 hours at 20-100 ° C and a relative humidity of 60-100%, 20 before autoclaving.

When designing the green moldings, plasticity is a highly desirable property. It has been found that excellent plasticity is provided by the process according to the invention due to the use of the ultrafine silica dust as silica and increasing lime addition increases the plasticity of the material.

In the specification to DK patent application no. 4682/79, which corresponds to EP patent application no. autoclaved fiber cement products. Hereby first green moldings are first produced by extrusion of a fiber-containing cement-silica pulp with an extremely low water / dry matter ratio (less than 0.16), ie. without dewatering a slurry, after which the green mold bodies are cured, e.g. by autoclave ring. In this specification, it is also mentioned that the products may have a cellulose fiber content. These are listed among other possible additives and their amount is not specified. The examples only deal with the production of such autoclaved products reinforced with 2-3% polypropylene fibers.

In the following, the invention is further illustrated by a number of examples.

The following materials were used in the examples:

Fibers: 20 AO cellulose: Cellulose fibers (Pinus) (Kraft cellulose), length: shorter than 4 mm, diameter: approx. 35 µm BO cellulose: Bleached cellulose fibers (Betula) with a grinding degree of approx.

43-50 ° SR, length: approx. 1.3 mm, diameter: approx. 30 µm in EO cellulose: Bleached cellulose fibers (Eucalyptus grandis and Eucalyptus urophylla) with a grinding degree of approx. 20 ° SR, length: approx. 1.0 mm, diameter: approx. 20 µm.

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Abaca: Cellulose fibers (Musa), length: approx. 6 mm, diameter: approx. 30 ^ .um.

Flax: Cellulose fibers (Linum) with a grinding degree of approx. 35 ° SR, length: approx. 6 mm, diameter: approx.

15 ^, um.

Silica: ACE sand: Silica sand containing at least 90% SiO2, specific surface (Blaine): approx. 3000 cm 2 / g.

5 Silica dust: Ultrafine filter dust from electrothermal production of metallic silicon or ferrosilicon, SiC> 2 content: 80-100%, specific surface (BET): approx. 25 m2 / g, average particle diameter: approx. 0.1 µm.

Fly ash Fly ash from power plant, specific surface (Blaine): approx. 3500 cm 2 / g.

Lime / lime-containing material:

Hydrate lime: 95% CaO, average particle size approx. 5 µm specific / 2 surface (BET): approx. 15 m / g.

E. cement: A special coarse Portland cement, specific surface (Blaine): approx.

2600 cm 2 / g.

10 LSC cement: Low alkali sulfate resistant Portland cement (max.

0.60%) (type V), specific surface (Blaine): approx. 3000 2 cm / g, C3 & content: approx. 1.5%.

White cement: Low alkali white base cement, specific surface (Blaine): approx.

2 4400 cm / g, C 2 A content: approx. 3%.

additives:

Attagel ^ D1SO: Commercially available colloidal, needle-shaped attapulgus clay product, with specific surface area: 210 m2 / g.

NYAD'S'G: Needle-shaped crystals of Wollastonite, with 80% having a size corresponding to a sphere diameter less than 4 µm, and 20% having a size corresponding to a sphere diameter less than 1 µm.

5 Fiber-reinforced plates were manufactured by laboratory experiments and on full industrial scale Hatschek and Magnani machines.

Laboratory tests:

Preparation Procedure.

Pulp Preparation: A solution of CaiOH 3 and CaSO 4, 2H 2 O saturated at 20 ° C was prepared in deionized water.

A portion of this solution plus the desired amount of ultrafine silica was introduced into a British Pulp Evaluation Apparatus where the silica was dispersed for 3 min. at 15,000 rpm. Then the fibers were added to the dispersion and the mixture was pulped for 15 minutes. at 3000 rpm.

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Preparation of slurry: The resulting fiber pulp and another portion of the above saturated solution were transferred to the vessel in a Diaf mixer, and the slurry was prepared by adding lime and / or calcareous material and any additives in an amount corresponding to a water to total weight ratio. dry matter of 10.

The resulting mixture was stirred at 4000 rpm. for 6 min.

Manufacture of green plates; A portion of slurry 10 corresponding to 109 g of dry matter was dewatered in a filtration apparatus, suction pressure 200 mm Hg. The resulting filter cakes were pressed into green plates in a Johns-Manville plate press.

Preparation of cured sheets: The green sheets are cured as follows. The green plates were placed on a glass plate and stored in a humidity box for 24 hours, relative humidity: approx. 95%, temperature 25 ° C. The plates were then autoclaved with 2.5 hours of setup time, 16 hours of autoclaving, and 2.5 hours of take-off time.

The physical properties of the slurry and cured boards 20 were measured as described below:

Testing Procedure:

Filtration time: An amount of slurry corresponding to 109 g of dry matter was dewatered in a filtration apparatus at a suction pressure equal to 200 mm Hg. A sudden decrease in suction pressure indicates the end of the filtration period. The filtration time is defined as the elapsed time from the start of the suction until the pressure drops.

Drying loss: The particle retention properties of the slurry were measured as follows: 3 slurry portions 30 a 440 g were dewatered in a filtration apparatus equipped with a 40 mesh screen, suction pressure: 30 mm Hg. The solids content of the filtrate was filtered off and the weight of the filtered material was determined. Solids loss is defined as the ratio of the solids content of the filtrate to the total solids content, expressed in% by weight.

BT-max dry and wet: The autoclaved plates were subjected to bending test experiments, during which the curvature of the samples was determined as a function of the load. A ZWICK 1454 4-point load test machine with 190 mm between the supports and a 35 mm torque arm was used. Power / deformation curves were recorded. BT-max indicates the bending stress at maximum load. The "wet" setting indicates that water-saturated plates which had been immersed in water for 48 hours were measured and "dry" were measured on plates dried for 48 hours at 110 ° C.

Example 1 Comparison between sheets made according to the invention and sheets made according to the prior art.

Three test rows were made with the manufacture of plates as described in the manufacturing procedure.

In Experiment 1, sheets according to the invention were made based on ultrafine silica. The green plates were pressed 2 at 15, 100 and 50 kp / cm and autoclaved at 140 ° C, 140 ° C and 180 ° C, respectively.

For comparison, in Experiments 2 and 3, sheets of the prior art were used, using ACE sand and fly ash as silica, respectively.

2

The green plates were pressed at 50 kp / cm and autoclaved at 180 ° C.

Compositions, expressed in percent by weight on a dry matter basis, and test results are shown in Table I. Here, and in the following, "(S)" denotes a comparative experiment.

It is apparent that the sheets according to the invention are characterized by greatly improved strength properties.

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Moreover, it is seen that the strength properties are improved by increasing pressure.

Example 2

Use of fly ash as component of the binder.

5 Seven test series were conducted with the manufacture of plates according to the manufacturing procedure.

In Experiment 4, fly ashless plates based on ultrafine silica dust were prepared. In Experiment 5, part of the ultrafine silica dust was replaced with fly ash, while in Experiment 5, sheets of the prior art were manufactured using exclusively fly ash as silica.

Compositions, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table II.

The autoclaving temperature was 140 ° C.

It is clear that the sheets according to the invention are characterized by greatly improved strength properties. It is further seen that partial substitution of ultrafine silica with fly ash leads to impaired strength properties.

In Experiments 7-10, the amount of 20 ultrafine silica dust used in Experiment 4 was maintained, while the cement was replaced with increasing amounts of fly ash as well as lime hydrate.

Compositions, pressures and test results are shown in Table II. The autoclaving temperature was 140 ° C.

By comparing the results of Experiments 4 and 7-10 25, it is seen that a high content of silica ensures excellent strength properties - even when significant parts of the cement are replaced with fly ash.

Furthermore, the carbohydrate addition was found to have an advantageous plasticizing effect on the green plates.

Example 3

Use of different types of cellulose fibers.

Three test rows were carried out with the manufacture of plates according to the invention.

Experiment 11 is identical to Experiment 4. In Experiments 12 and 10 13, the fibers used in Experiment 11 were replaced with other fiber combinations.

Compositions, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table III. The autoclaving temperature was 140 ° C.

15 It is clear that products with excellent strength properties are available in all test series.

Example 4

Use of different types of cement.

Three test series were conducted with the preparation of sheets of the invention.

Experiment 14 is identical to Experiment 4. In Experiments 15 and 16, the LSC cement used in Experiment 14 was replaced with other cement types.

20 U9382

Compositions, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table IV. The autoclaving temperature was 140 ° C.

It is clear that in all series of experiments 5 products with excellent strength properties are obtained.

Example 5

Effect of incorporation of Wollastonite crystals.

Two series of test plates were prepared in accordance with the invention, experiment 17 without experiment 10 18 with the addition of Wollastonite crystals.

Compositions, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table V. The autoclaving temperature was 140 ° C.

The test results show that the incorporation of Wolla-15 stonite crystals results in a significant reduction in filtration time and of the dry matter loss with substantially unchanged strength properties.

Example 6

The effect of fiber concentration on the strength properties.

Eight test rows were made with the manufacture of plates according to the manufacturing procedure.

In Experiment 19, plates having a fiber content of 4%, i.e. lower than the minimum limit specified in claim 1. In experiments 20 and 21, plates of the invention were prepared with 12 and 15% 2 fibers, respectively. The plates were pressed at 15 kp / cm and autoclaved at 140 ° C.

In experiments 22-26, plates having a cellulose fiber content of 5 to 30% were prepared.

Compositions, expressed in percent by weight on a solids basis, pressure and test results are shown in Table VI.

The test results show that a high cellulose fiber content is necessary to obtain good strength properties 10 (for products of fairly low bulk weight) as well as reasonable filtration conditions. Furthermore, it is seen that the optimum cellulose fiber content is in the range of 10-20%.

Example 7

Effect of silica concentration on strength properties.

Six test rows were performed with the manufacture of sheets according to the invention.

In experiments 27-32, plates with an ultrafine silica dust content were increased from 20-40%.

Compositions, expressed in percent by weight on a dry matter basis, 20 compressive pressures and test results are shown in Table VII.

The test results show that an advantageous combination of excellent strength properties and acceptable filtration times is provided when the content of ultrafine silica dust is in the range of 18-35%.

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Industry Experiment Example 8

Attempts on a full-scale Hatschek machine Attempt Hl.

5 178 kg of BO cellulose was pulped for 10 min. in 3200 1 water in 3 and 6 m Solvo hydropulper. Then the pulp was refined in a Black Clawson disc refiner until it had a grinding degree of approx. 45 ° SR. 550 kg of ultrafine silica dust was dispersed in 4000 l of water for 10 min, after which 104 kg of AO cellulose was added, which was pulped for 20 min.

4754 kg of this pulp was combined with the first pulp and additional water was added to a total weight of 8600 kg. 1845 kg of the resulting pulp was mixed with 300 kg of LSC cement for 10 minutes, after which 15 water was added to a water / dry matter ratio of approx. 10th

The resulting sludge was processed in a known way into flat plates on a Hatschek machine.

The flat plates were pressed for 45-60 min.

The pressed sheets having a thickness of 6 mm, 20 were cured in a curing channel for 8 hours at approx. 60 ° C.

The plates were then autoclaved for 16 hours at 140 ° C, with a recording time of 4 hours and a recording time of 4 hours.

testing ♦

Two values for the BT-max of the plates were measured: BT-max 1 (with breakage parallel to the production direction).

149832 23 BT-max t (with fracture perpendicular to the production direction}.

The terms "wet" and "dry" are the same as stated above, "stock" refers to the fact that the plates after auto-5 claving have been conditioned for approx. 1 month at atmospheric conditions before measurement.

Composition, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table VIII.

Experiment H2.

By analogy, plates according to the invention were prepared with hydrate-lime-based binder.

Composition, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table VIII.

The plates were tested for water permeability and the 15 results showed 10 times greater density than for ordinary asbestos cement. Furthermore, the plates underwent frost / thaw tests, and again here the result was significantly better than for ordinary asbestos cement. After exposure for 1 hour in water and then 23 hours at 20 ° C dry heat with 50 repeats, the strength properties of the plates remained unchanged. The ability of the panels to protect the underlying flammable material from fire was found to be equivalent to asbestos conditions.

Experiments H3 and H4.

Analogously, sheets of the invention were prepared with LSC cement-based binders containing flax cellulose and AO cellulose, respectively.

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Composition, expressed in percent by weight on a dry matter basis, pressure and test results are shown in Table VIII.

Experiment H5.

Full industrial scale corrugated sheets 5 were prepared as follows: A slurry of the same composition as in Experiment H4 was prepared and processed into 10 flat plates in a Hatschek machine as described in Experiment H1.

The flat sheets were then processed into corrugated sheets in a conventional wave machine. Hereby, 10 'corrugated sheets were produced having a wavelength of 177 mm and a height (i.e., distance from the top of the corrugated valley to the top of the corrugation) of 51 mm (plate thickness 6 mm).

The plates were cured and autoclaved as described in Experiment H1. Some plates were pressed for 45-60 min. at 100 2 15 kp / cm before curing.

Sample plates were excised by the autoclaved plates and two BT-max values were measured on the test plates: BT-max 1 (with fractures parallel to the waves) and BT-max t (with fractures perpendicular to the waves). The terms "wet" and "stock" 20 are the same as indicated above.

The following results were found:

Unprinted plates: Weight: 1.04 g / cm; BT-max 1 wet: 7.6 MPa; BT-max t wet: 10.7 MPa; BT-max 1 bearing: 12.1 MPa; BT-max t storage: 16.8 MPa.

3 25 Pressed plates: Room weight: 1.34 g / cm; BT-max 1 wet: 12.6 MPa; BT-max t wet: 17.8 MPa; BT-max 1 bearing: 27.4 MPa; BT-max t storage: 29.4 MPa.

149882 25

The plates exhibited excellent frost resistance and water impermeability.

Example 9

Attempts on a Magnani machine on a full industrial scale.

An aqueous slurry having a water / dry matter ratio of approx.

2 containing 12 parts by weight of cellulose fibers, 20 parts by weight of ultrafine silica dust, 16 parts by weight of fly ash and 52 parts by weight of LSC cement were prepared as described in Example 8.

The slurry was pumped into a Magnani machine where it was dewatered into corrugated corrugated sheets (wavelength: 147 mm, height · 48 mm, thickness: 6-7 mm). The pressed sheets were cured and autoclaved as described in Example 8.

Sample plates were cut from the autoclaved plates, 15 and two BT-max values were measured on the sample plates: BT-max 1 and BT-max t. The terms "1", "t", "wet" and "stock" are as indicated in Experiment H5. The following test results were found:

Space weights in the range 1.04-1.13; BT-max 1 wet in the range 7.5-12 MPa; BT-max t wet in the range of 9-14 MPa; BT-max 1 stock in the range of 13-20 MPa; BT-max t stocks in the range of 16-22 MPa.

It is seen that excellent strength properties are obtained in varying cellulose fiber combinations.

26 149882

Table I

Experiment # 1 2 (S) 3 (S) AO cellulose 3.3 3.3 3.0 BO cellulose 6.7 6.7 5.0 ACE sand - 30.3

Fly ash - - 31.0

Silica dust '30, 3

Hydrate lime 28.1 28.1 28.7

Attagel 150 2.0 2.0 2.0

New G 29.6 29.6 30.3

Filtration time (sec) 815 34 27 Solids loss (%) 2.9 2.9 3.0 2

Pressure pressure: 15 kp / cm 3

Room weight (g / cm) 1.00 BT-max wet, (MPa) 13.1 BT-max dry, (MPa) 20.6 2

Pressure pressure: 100 kp / cm 3

Room weight (g / cm) 1.23 BT-max wet, (MPa) 18.0 - - BT-max dry, (MPa) 31.3 2

Pressure pressure: 50 kp / cm

Volume weight (g / cm 2) 1.14 1.06 1.02 BT-max dry, (MPa) 25.8 9.6 3.4

Table II

27 140882

Experiment No. 4 5 6 (S) AO cellulose 8 88 BO cellulose 7 77

Fly ash - 9 24

Silica dust 24 15 LSC cement 61 61 61

Filtration time (sec) 271 115 32 Loss of solids (%) 3.3 3.6 2.5

Pressure pressure: 15 kp / cm 2

Room weight (g / cm 2) 1.21 1.19 0.95 BT-max wet, (MPa) 22.6 16.4 6.2 BT-max dry, (MPa) 29.9 25.8 10.4 2

Pressure pressure: 100 kp / cm

Room weight (g / cm 2) 1.45 1.39 1.09 BT-max wet, (MPa) 33.9 24.6 9.0 BT-max dry, (MPa) 35.2 30.0 13.6

Table II (continued) 28 169882

Experiment # 7 8 9 10 AO cellulose 888 8 BO cellulose 777 7

Fly ash 5 10 15 25

Silica dust 24 24 24 24

Hydrate lime - 5 8 13 LSC cement 56 46 38 23

Filtration time 263 223 240 234 (sec) Loss of solids (%) 3.8 3.5 3.9 3.5 2

Compression pressure: 15 kp / cm

Room weight (g / cm 2) 1.22 1.14 1.10 BT-max wet, (MPa) 19.0 18.9 17.7 15.0 BT-max dry, (MPa) 26.9 25.4 24.6 23.0 2

Pressure pressure: 100 kp / cm

Room weight (g / cm 2) 1.45 1.39 1.33 1.25 BT-max wet, (MPa) 28.6 27.1 24.9 21.7 BT-max dry, (MPa) 32.7 33.5 34.2 27.1

Table III

149882 29

Forsøg.nr. 11 12 13 AO cellulose 8 8 BO cellulose 7 -

Abaca - 8 EO cellulose -77

Silica dust 24 24 24 LSC cement 61 61 61

Filtration time (sec) 271 131 174 Loss of dry matter (%) 3.3 3.6 4.1 2

Compression pressure: 15 kp / cm

Room weight (g / cm3) 1.21 1.30 1.28 BT-max wet, (MPa) 22.6 25.1 22.0 BT-max dry, (MPa) 29.9 28.8 29.8 2

Pressure pressure: 100 kp / cm

Volume weight (g / cm3) 1.45 1.51 1.52 BT-max wet, (MPa) 33.9 33.8 31.6 BT-max dry, (MPa) 35.2 36.9 37.9

Table IV

149882 30

Experiment No. 14 15 16 AO cellulose 88. 8 BO cellulose 7 7 7

Silica dust 24 24 24 LSC cement 61 E cement - 61

White cement - 61

Filtration time (sec) 271 259 242 Loss of dry matter (%) 3.3 2.8 3.3 2

Press Press; 15 kp / cm

Room weight (g / cm 2) 1.21 1.19 1.20 BT-max wet, (MPa) 22.6 17.1 21.8 BT-max dry, (MPa) 29.9 26.5 26.0 2

Press Press; 100 kp / cm

Room weight (g / cnf *) 1.45 1.46 1.45 BT-max wet, (MPa) 33.9 23.9 29.6 BT-max dry, (MPa) 35.2 32.6 29.7

Table V

149882 31

Experiment # 17 18 AO cellulose 8 8 BO cellulose 7 7

Silica dust 24 24 E cement 61 51

New G 10

Filtration time (sec) 242 180 Loss of dry matter (%) 3.3 2.9 2

Press Press; 15 kp / cm

Room weight (g / cm 2) 1.20 1.19 BT-max wet, (MPa) 21.8 20.1 BT-max dry, (MPa) 26.0 26.6 2

Pressure pressure: 100 kp / cm 3

Room weight (g / crti) 1.45 1.43 BT-max wet, (MPa) 29.6 29.7 BT-max dry, (MPa) 29.7 34.9

Trial No. 19 (S) 20 21

TABLE VI

149882 32 AO cellulose 4 88 BO cellulose - 47

Silica dust 24 24 24 LSC cement 72 64 61

Filtration time (sec) 1500 427 271 Solids loss (%) - 4.4 3.3 2

Pressure (kp / cm) 15 15 15

Room weight (g / ciri) 1.55 1.31 1.21 BT-max wet, (MPa) 13.9 18.8 22.6 TABLE VI (continued)

Experiment No. 22 23 24 25 26 149882 33 AO cellulose 3 69 12 18 BO cellulose 2 4 6 8 12

Silica dust 26.8 25.4 24 22.6 19.8 LSC cement 68.2 64.6 61 57.4 50.2

Filtration time (sec) 549 403 166 124 57 Solids loss (%) 13.3 5.4 4.3 1.8 1.3

Pressure pressure (kp / cm 2) 100 100 100 100 100

Temperature program run; 140 ° C

Room weight (g / cm 2) 1.73 1.59 1.48 1.33 1.15 BT-max wet, (MPa) 14.6 24.5 24.2 20.6 15.8

Temperature program run; 180 ° C

Room weight (g / cm 2) 1.74 1.58 1.46 1.26 1.14 BT-max wet, (MPa) 11.4 17.8 22.8 22.6 18.8

Trial No. 27 28 29 30 31 32 149882 34

TABLE VII

AO cellulose 8 88888 BO cellulose 7 77777

Silica dust 20 24 28 32 36 40 LSC cement 65 61 57 53 49 45

Filtration time (sec) 189 221 301 227 302 349 Loss of dry matter (%) 3.2 2.3 4.2 2.4 2.7 2.4

Pressure pressure (kp / cm 2) 100 100 100 100 100 100

Autoclave temperature: 140 ° C

Volume weight (g / cm3) 1.45 1.48 1.49 1.41 1.39 1.35 BT-max wet, (MPa) 23.4 24.3 28.7 27.4 25.5 24.2

Temperature program run; 180 ° C

Room weight (g / cm3) 1.45 1.45 1.47 1.43 1.41 1.39 BT-max wet, (MPa) 19.1 22.3 25.6 29.1 29.2 27.5

TABLE VIII

Test No. H1 H2 H3 H4 149882 35 AO cellulose 8 3.2 - 6 BO cellulose 7 6.4 4 4 Listen - - 6 -

Silica dust 24 30.3 20 20

Hydrate lime - 28.1 LSC cement 61 - 60 60

New G 29.6 10 10

Attagel 150 - 2.4

Pressure pressure (kp / cm 2) 223 205 190 190

Room weight (g / cm 2) 1.3 1.2 1.5 1.4 BT-max 1 wet, (MPa) 22.5 17.2 20.4 24.4 BT-max t wet, (MPa) 36 , 0 23.9 30.1 38.2 BT-max 1 dry, (MPa) 26.6 26.0 27.6 33.8 BT-max t dry, (MPa) 44.9 40.4 34.4 47.6 BT-max 1 bearing, (MPa) 30.9 21.8 25.3 28.8 BT-max t bearing, (MPa) 55.5 37.2 33.6 49.6

Claims (10)

149882 Patent Cray A process for the production of autoclaved fiber-reinforced moldings having a weight of at least 600 kg / m , calculated on the total solids content, silica, lime and / or calcareous material, and optionally plasticizers in the form of colloidal silica and / or clay particles and other additives containing more water than necessary to cure the calcium silicate binder on which green molds are made. by dewatering the slurry, after which the green moldings are autoclaved, possibly. after pressing and hardening, characterized in that the aqueous slurry calculated on a dry weight basis contains 5-30%, preferably 8-20%, especially 12-16% fibers, preferably at least 8% cellulose fibers; 15-50%, preferably 18-35%, especially 18-25% silica in the form of ultrafine silica dust with a specific surface area of 5-200 m2 / g, and an average particle diameter less than approx. 0.5 ^ um; 20-80%, preferably 30-70%, especially 45-65% lime and / or calcareous material; as well as 0-40% additives. Process according to claim 1, characterized in that at least part of the cellulose fibers are ground to a fineness of 20-60 ° Shopper Riegler. A method according to claims 1-2, characterized in that the fibers comprise highly fibrillated polyethylene or polypropylene fibers. 149882 Process according to claims 1-2, characterized in that cellulose fibers are used exclusively as fibers. 5. A process according to claims 1-4, characterized in that the aqueous slurry, calculated on a dry weight basis, contains 8-20%, preferably 12-16% cellulose fibers, of which up to half is ground to a fineness of 20-60 ° Shopper Riegler, preferably 35-50 ° Shopper Riegler. Process according to claims 1-5, characterized in that fine silica dust from electrothermal production of silicon or ferrosilicon with a specific surface area 2 per cent is used as ultra-fine silica dust. 25 m / g and an average particle diameter of approx. 0.1 µm. Process according to claims 1-6, characterized in that hydrate lime is used as lime and / or calcareous material. 8. A process according to claims 1-6, characterized in that portland cement is used as lime and / or calcareous material. Process according to claims 1-6, characterized in that a mixture of Portland cement and hydrate lime is used as lime and / or lime-containing material. Process according to claims 1-9, characterized in that the autoclaving is carried out at temperatures between 100 and 240 ° C, preferably at 130 - 190 ° C.