DE2816457A1 - MIXTURE, PARTICULARLY BUILDING MATERIAL MIXTURE, AND METHOD FOR PRODUCING MOLDED BODIES FROM THIS MIXTURE - Google Patents

Description

Eternit-Verke Ludwig Hatschek, Vöcklabruck (Austria) and Chemiefaser Lenzing Aktiengesellschaft, Lenzing (Austria)

Mixing, especially Baus toi * f mixing, and method for Manufacture of moldings from this mixture

The invention relates to a mixture, in particular a building material mixture, for producing, for example, plate-shaped or tubular shaped bodies, consisting of binders, preferably hydraulic, e.g. inorganic binders such as cement, gypsum, alkali silicate or alkali aluminate, and from fibrous or fibrous materials , and optionally from fillers or additives and / or water.

809844/0759

The invention further relates to a method for producing shaped bodies from this mixture.

It is generally known that asbestos fibers are very well suited for the reinforcement and the production of, especially thin-walled, molded parts made of cement because of their good carrying capacity for cement and because of their strength contribution. Asbestos is a natural product and as such is not available in unlimited quantities. The larger deposits are also located in other parts of the world, which means long transport routes. Since the economy’s demand for asbestos is growing without the production of mines increasing to the same extent, a shortage of this raw material is to be expected in the next few years. In addition, the cost of this natural product is constantly increasing.

Considerations have therefore already been made repeatedly as to which other substances make the asbestos fibers can be replaced. In this context there are e.g. mineral wool, glass fibers, mica and various Animal fibers have been suggested, yet all of these fabrics have proven themselves - primarily for reasons of lack Load-bearing capacity and strength - proven to be inadequate (li.IIayden: Fundamental questions of manufacture von Asbestzement, Berlin 1042).

In particular, it is also known that organic fibers, primarily cellulose fibers such as cellulose, for * the production of molded parts from cement are suitable, but that such strengths of the molded parts as in Use of asbestos fibers observed cannot be achieved. Disadvantage when using cellulose fibers is also the reduced frost resistance of molded parts, thanks to the well-known ability of cellulose for water absorption and release is effected. I.e. that

8098U / 075Ö

Molded parts made with the help of cellulose fibers xvrden, cannot be exposed to the elements and their application is therefore largely restricted to indoor spaces.

Short cut, synthetic fibers similar to those used in the textile industry with longer lengths are suitable for due to their low carrying capacity Cement and because of the low affinity · for hardened cement, not for the production of molded parts from cement. Such short organic fibers, or glass fibers with a length of several millimeters, can only be small Quantities to improve the impact strength of the products are added. The addition of organic fibers but must not exceed a certain small percentage, because it is different when processing with known methods otherwise bunch up into inseparable balls.

The invention is based on the object of providing a mixture, in particular a building material mixture, for the production of To create molded parts with largely similar mechanical and chemical properties as asbestos cement However, the raw material asbestos has been replaced by another, especially synthetic, product.

According to the invention, this is achieved in the case of a mixture, in particular a building material mixture, of the type mentioned at the outset achieved that as fibrous or fibrous substances alone or mainly or predominantly, in particular synthetic, fibrids, preferably from organic, hydrophilic polymers are used.

Fibrids are two- or three-dimensionally oriented, fibrous or fibrous structures The projections and / or depressions located on the surface are understood, their structure e.g. by explosive

8098U / Ö75Ö

Evaporation of the solvent or precipitation with high turbulence is achieved. These include flake-like or similar branched structures, structures with a tufted fiber or feathery structure similar to asbestos, or structures, in which a punctiform or core-shaped center has fringes protruding like tufts.

• The described structure of the fibrids results in good carrying capacity for cement particles. Also favors this structure anchors the fibrids well in the hardened cement molding and supports the formation of the fleece in the course of processing with known methods »

The same production method as for asbestos cement can thus be retained.

The fibrids are preferably made of polymers such as polyethylene, polypropylene, polyacrylonitrile, polystyrene, Polyvinyl alcohol, polyvinyl chloride, polyamides or polyesters.

The well-known, low affinity of synthetic fibers can be reduced by incorporating hydrophilic groups such as hydroxyl, Carboxyl, carboxyl, and amino groups into the base polymer avoid the fibrids, and thus improve their anchoring in the molded part even further. There are therefore according to the present Invention advantageous fibrids of copolymers of ethylene, propylene, styrene, vinyl chlorides or des Acrylonitrile with vinyl or acrylic compounds bearing hydrophilic groups such as vinyl acetate, vinyl alcohol, hydroxyethyl methacrylate, Acrylic acid and methacrylic acid and the like used. The copolymers can be used as random copolymers or as so-called block and graft copolymers are present. The hydrophilic groups in the copolymers can also be through polymer-homologous reactions, such as for example the production of hydroxyl groups by splitting off ester groups in vinyl ester units in

8098U / 07S9

a copolymer.

It is possible that the fibrids consist of copolymers of polyamides or polyester when they are produced Hydrophilic groups such as hydroxyl, carboxyl groups, etc., multi-functional alcohols, amines or Carboxylic acids can be used as condensation partners.

It is also possible that the fibrids are made from graft polymers exist in the grafted side chain carry hydrophilic substituents.

In addition, the fibrids can be an ordered mixture of two or more synthetic and / or reshaped natural ones They are more polymeric, i.e. as fibrids with a so-called bi- or multi-component structure. It can preferably one or more polymer components are hydrophilic in nature. The individual polymer components can be arranged to each other in a manner known per se, as core and shell, side by side, as continuous or interrupted incorporation of a polymer in a matrix of another polymer.

It can also be advantageous that the fibrids are made from the various polymers or copolymers in a mixture with each other or conventional staple fibers, such as viscose staple fibers, and fibers made of polyvinyl alcohol, polyvinyl chloride, Polyamide, polyester or polyacrylonitrile, and / or mixed with mechanical and / or chemical pulp, exist.

The fibrids can be short-fibered or fibrillated or fibrillatable form can be used. The latter can be achieved through appropriate measures in the production of the fibrids by creating flaws by means of foaming or the incorporation of foreign substances, e.g. inorganically extracted

809844/0759

soluble salts or incompatible polymers or by mechanical measures. Under fibrillation becomes in this context a splitting · or a Opening up the fibrids for the purpose of enlarging their surface Understood. The fibrids are manufactured already mostly inhomogeneous, but their splintering improves their carrying capacity for cement.

It has proven to be advantageous that 1 - 40 wt. -Fo, preferably 3 - 30 wt .- ^, of the mixture of fibrids alone or mixtures of the fibrids with asbestos fibers and / or other inorganic fibers, such as rock wool, slag wool, glass fibers , Carbon fibers - so-called whiskers, boron fibers, wollastonite fibers or aluminum oxide fibers.

To improve the retention of the hydraulic binders on the fibrids, preferably 0.01 2 Yo by weight based on binder, cationic polyelectrolytes or the like can be added.

The method according to the invention for processing the present mixture is basically characterized in that that first the fibrids and the binding agent, and optionally other fibers and / or filler or Aggregates and water are mixed, whereupon these Mixture of the shaping, in particular with application to a sieve or the like, is supplied. The inventive Mixing can then in particular by spraying, injection molding, extrusion or casting or centrifugal casting are processed.

In an embodiment of the method according to the invention it is provided for the continuous production of molded parts that the mixture located in an aqueous suspension

8098U / 0 759

Schung is deposited on a rotary or Fourdrinier machine. The other known synthetic fibers, however, cannot be used on a round or fourdrinier machine, because the formation of a fleece a ^^ s bevel] - and cement does not appear on the sieve. The sieve only holds back the fiber while the cement passes through the sieve into the backwater got. It was therefore surprising that the fibrids together with the. Binder on a sieve a fleece, similar as when using asbestos fibers. It is possible to produce asbestos-free mixtures of fibrids and binders on one To process long or cylinder sieve machine to moldings. The essential thing about the method according to the invention is here the formation of the fleece through the shape typical of the fibrids, the chemical compound that makes up the fibrids exist, is not or is not solely decisive. All that is required is permanent alkali resistance.

For the discontinuous production of moldings from the mixture according to the invention, it is expedient that the masses of aqueous suspension are sucked onto a supporting fabric.

The moldings can be compressed after they have been produced.

The hardening of the binder can take place in the air or in water at temperatures below about kO C, or in the air at temperatures between essentially hO - 100 ° C or in an autoclave under pressure at temperatures between essentially 100 - 180 ° C.

Before being mixed into the, in particular inorganic, hydrophilic, binding agents, the fibrids can be used in a mechanical, preferably fibrillating, treatment.

8098U / 0759

It is possible that fiber-like or fibrous substances are used that are ground together with binders and / or fillers or additives, and optionally with water, are converted into fibrids.

It can also prove to be expedient that the fibrids and the binding agent, e.g. cement clinker, are ground together. The marriage can be done dry or with the addition of barrel.

Shaped bodies that can be produced by means of the mixture according to the invention are, for example, plates, in particular corrugated sheets, or pipes, pipe fittings, and similar hollow bodies into consideration.

In addition to the inorganic binders already mentioned, organic binders, such as synthetic resin can be used. The use of non-hydraulic binders is also possible.

At most, quartz powder, sand or the like can be considered as fillers.

The processing of the mixture may in particular long or cylinder machines, as they are known for processing of asbestos cement, or in forms etc. The mixture is processed in each case with the addition of water, an aqueous suspension being formed.

In the drawing, embodiments are of usable for the inventive mixing fibrids, and apparatus shown to implement the method according to the invention.

Show it:

1 to 5 exemplary embodiments of fibrids, in an enlarged, schematic view, and

809844/0759

Fig. 6 shows an embodiment of a device for Implementation of the Vex-driving according to the invention.

Pig. 1 shows a tuft-like branched fibrid, FIG. 2 an essentially pinnate fibrid, FIG. 3 a fibrid similar to a sea urchin, FIG. K a fibrid in the form of a flake, and FIG Wells, of course, many other exemplary embodiments are also possible.

The device shown in FIG. 6 for carrying out the method according to the invention consists of a mixer or agitator 1 and a cylinder sieve machine 2. A mixture of fibrids with water and cement are introduced into the agitator 1 and mixed with one another. The suspension obtained in this way is sucked in through a line 3 by a pump h and fed to the cylinder sieve machine 2 via a line 5. The cylinder mold machine 2 is provided with a cylinder mold 6, from which the web formed of fibrids and binding agent is removed by means of a couch roll 7 and an endless felt web 8. This web is then dewatered by means of devices not shown in detail and wound onto a format roller.

Examples:

a) 2 parts by weight of polyethylene fibrids are ground in a Mahlholländer with 80 parts by weight of water for 30 minutes, then pumped into a mixing vessel and mixed with 18 parts by weight of Portland cement mixed by pumping. The suspension is suspended continuously on a cylinder sieve. The emerging Fabric made of cement and polyethylene fibrids is up wound onto a format roller to a thickness of e.g. 6 mm. After separation from the format roller, the resulting Plate stored for 28 days to allow the cement to harden.

8098A4 / 07B9

b) 12 parts by weight of fibrids, consisting of copolyraeren
of ethylene and vinyl acetate are 30 minutes in one
Ground ball mill, suspended in 45 parts by weight of water and with 60 parts by weight of Portland cement and 60 parts by weight
mixed with fine quartz sand. The suspension is mixed well by stirring and poured into a sieve mold. The resulting plate was further dehydrated by pressing, stored for a day and cured in an autoclave at 160 ° C. for 20 hours.

c) 9 parts by weight of fibrids from a copolymer of ethylene and vinyl alcohol are mixed with 150 parts by weight of water in
hit a disintegrator. The mixture is in a
Pumped vessel, mixed with 400 parts by weight of water and 91 parts by weight of Portland cement and stirred. The suspension is sucked in a tub onto a mold with a permeable supporting fabric. The formed part is dewatered by pressing and cured at temperatures of 50-70 ° C. for 6 hours.

d) 11 parts by weight of polypropylene fibrids are ground in a pan for 10 minutes, placed in a mixing vessel and mixed with 100 parts by weight of water and 95 parts by weight of Portland cement
offset. The suspension is mixed well and formed into a molded part in an injection machine with the application of pressure. The part is hardened at temperatures between 70-80 ° C.

e) 2 parts by weight of polyacrylonitrile fibrids are ground in a pan for 10 minutes, stirred into 100 parts by weight of water and mixed with 20 parts by weight of cement. The suspension is mixed well and fed to a cylinder sieve machine. The sheet-like structure formed on the screen is wound into tubes on a format roller. After the cement has set
the tubes are stored in a water bath for 10-30 days.

809844 / 07S9

f) As in example e), but fibrids of polyacrylonitrile and / or its copolymers, which are alkaline, were partially hydrolyzed.

g) 1.5 parts by weight of polyethylene fibrids are milled Milled for 10 min. Before the end of the grinding process 0.5 part by weight of polyacrylonitrile fibers, 6 mm long, in the Poured pan mill. 100 parts by weight of water are added to the ground fibers in a mixing vessel and so on Stirred for a long time until all the fiber clumps have dissolved. Then 20 parts by weight of Portland cement are added and the mass is stirred until it becomes homogeneous. The suspension will processed on a cylinder mold machine to 6 mm thick plates. The product takes 28 days to harden the cement stored at room temperature.

h) 2 parts by weight of fibrids made from a terpolymer of acrylonitrile and hydroxyethyl methacrylate with methacrylic acid are ground in a pan for 10 minutes and placed in a grinder in which there is 100 Gextf. parts of water are located. They are ground until all lumps and knots have loosened and with 20 parts by weight of cement offset.

The homogeneously mixed suspension is fed to a Fourdrinier machine and the resulting sheetlike structure wound on a format roller up to a thickness of 6 mm. After being separated from the format roller, the resulting Plate stored for 28 days to allow the cement to harden.

i) 1 part by weight of polyethylene fibrid is combined with a Part by weight of asbestos in a pan mill with the addition of 0.2 parts by weight Ground water. 100 parts by weight of water are added to the mass in a mixer and the mixture is vigorously stirred until all bundles have come loose. After adding 20 parts by weight of cement, the suspension is continuously increased

8098U / Ö759

Round sieve bloated. The resulting fabric from Cement, polyethylene fibrids and asbestos are wound onto a format roller up to a thickness of 10 mm. After detaching The resulting plate is stored by the format roller for 28 days until the cement hardens.

j) 1.5 parts by weight of polyethylene fibrids and 100 parts by weight of ¥ water are placed in a Mahlholländer and treated as long as until all of the lumps have dissolved. The mass is transferred to a mixer and mixed with 0.5 parts by weight of basalt wool and 20 parts by weight of Portland cement. To improve the retention capacity of cement on a cylinder sieve 0.2 part by weight of a cationic polyelectrolyte is added. The suspension is continuously on a Round sieve bloated. The resulting fabric from Cement, polyethylene fibrids and basalt wool are wound onto a format roller up to a thickness of 3 mm. After detaching The resulting plate is stored from the format roller for 28 days to allow the cement to harden.

k) 6 parts by weight of polyethylene fibrids are 30 min in disrupted in a ball mill and added to 450 parts by weight of water given with 6 parts by weight of unbleached wood pulp. 120 parts by weight of cement are mixed in with stirring. The suspension is poured into a sieve mold. The resulting plate is further dewatered by pressing, stored for a day and hardened in an autoclave at 16O C for 20 hours.

l) 6 parts by weight of polyethylene fibrids and 6 parts by weight of sulfate pulp and 1 part by weight of asbestos are mixed with 1000 parts by weight Water added. The suspension is fed to a disintegrator and stirred vigorously for 10 minutes. Among other things, With careful stirring, 60 parts by weight of cement and 60 parts by weight are added Quartz flour mixed in. The mass is poured into a sieve mold. The resulting molded body is further expanded by pressing drained and stored for 28 days to harden the cement.

809844/0759

m) 12 parts by weight of fibrids from graft polymers of vinyl alcohol on polyethylene are mixed through a high-speed mixer distributed in 1000 parts by weight of Yasser. 120 parts by weight of Portland cement are added to the suspension. the The mass is poured into a sieve mold. The resulting shaped body is stored for 28 days to allow the cement to harden.

n) 12 parts by weight of polyacrylonitrile fibrids, the cellulose contained in finely divided, oriented Fox-m Unlocked for 25 min in a lamp ball mill and with a total of 450 parts by weight of water mixed. After adding The suspension was poured into a sieve mold with 120 parts by weight of cement poured. The resulting plate was further dewatered by pressing, stored for one day to harden and then im Autoclave hardened at 160 C for 20 hours.

8098U / 0759

eerse

ife

Claims (1)

Claims \ ^w * 1. Mixing ring, in particular building material mixture, for producing of, for example, plate-shaped or tubular shaped bodies, consisting of binders, preferably hydraulic, e.g. inorganic binders such as cement, gypsum, alkali silicate or alkali aluminate, and made of fibrous or fibrous materials, and optionally from fillers or aggregates and / or! barrels, thereby characterized in that as fibrous or fibrous Substances alone or primarily or predominantly, in particular synthetic, fibrids, preferably made of organic, hydrophilic polymers can be used. 2. Mixture according to claim 1, characterized in that the fibrids are made of polymers such as polyethylene, Polypropylene, polyacrylonitrile, polystyrene, polyvinyl alcohol, polyvinyl chlorides, polyamides or polyesters exist. 3. Mixture according to claim 1 or 2, characterized in that the fibrids are made from copolymers of ethylene, Propylene, styrene, vinyl chlorides or acrylonitrile with polymerizable vinyl or acrylic compounds bearing hydrophilic groups such as vinyl acetate, vinyl alcohol, Hydroxyethyl methacrylate, acrylic acid, methacrylic acid and / or the like exist. H. Mixture according to one of Claims 1 to 3 », characterized in that the fibrids consist of copolymers of polyamides or polyesters, in the production of which hydrophilic groups such as hydroxyl, carboxyl groups and other polyfunctional alcohols, amines or carboxylic acids are used as condensation partners. ORIGINAL INSPECTED 8098 / U / O759 5. Mixture according to one of claims 1 to 4, characterized characterized in that the fibrids from the graft polynate under claim 3 mentioned base polymers exist which in the grafted side chain hydrophilic substituents wear. 6. Mixture according to one of claims 1 to 5, characterized in that the fibrids are made from the different polymers or copolymers in a mixture with one another or conventional staple fibers such as viscose staple fibers and fibers made of polyvinyl alcohol, polyvinyl chloride, polyamide, polyester or polyacrylonitrile, and / or mixed with mechanical and / or chemical pulp. 7. Mixture according to one of claims 1 to 6, characterized in that the fibrids with substantially short fibers Form are used. 8. Mixture according to one of claims 1 to 7i characterized in that the fibrids are used in fibrillated or fibrillatable form. 9. Mixture according to one of claims 1 to 8, characterized in that 1 - 4θ wt. Fo, preferably 3 30 wt .- ^, the mixture of fibrids alone or mixtures of fibrids with asbestos fibers and / or other inorganic fibers, such as For example rock wool, slag wool, glass fibers, carbon fibers - so-called whiskers, boron fibers, wollastonite fibers or aluminum oxide fibers. 10. Mixture according to one of claims 1 to 9, characterized in that to improve the retention of the hydraulic binders on the fibrids, preferably 0.01-2 % by weight based on the binder, cationic polyelectrolytes or the like are added. 8098U / 07SI TT. Process for the production of moldings from a mixture according to one of claims T to TO, characterized in that initially the fibrids and the Binder, and, optionally, further fibers and / or Fillers or aggregates and water are mixed, whereupon this mixture of the shaping, in particular with application to a sieve or the like, is fed. T2. Method for producing molded parts from the Mixture according to one of Claims T to TO or according to Claim TT, characterized by spraying, injection molding, Extruding or pouring the masses. T3 · Process for the continuous production of molded parts from the mixture according to one of Claims T to TO, or according to claim TT or T2 by depositing the mixture, which is in an aqueous suspension, on a round or fourdrinier machine. Τ4. Process for the discontinuous production of Molded parts from the mixture according to one of Claims T to TO or according to one of Claims T to T3, characterized by sucking the masses from aqueous suspension onto a supporting tissue. T5. Method according to one of Claims TT to ik _f, characterized in that the molded parts are pressed after they have been produced. To. Process for producing molded parts from the mixture according to one of Claims T to TO or according to one of Claims TT to T5 », characterized in that the hardening of the binder takes place in air or in water at temperatures below about kO C. B098U / 07SÖ 17 · Process for the production of molded parts from the Mixture according to one of Claims 1 to 10 or according to one of Claims 11 to 13, characterized in that the The binder hardens in air at temperatures between essentially 40 to 100.degree. 18. A method for producing molded parts from the mixture according to one of claims 1 to 10, or according to one of claims 11 to 15> characterized in that the hardening of the binder in the autoclave under pressure at temperatures between 100 to 180 C substantially he follows. 19. Method according to one of Claims 11 to 18, characterized in that the fibrids are mixed in in the, in particular inorganic, hydrophilic, binding agents of a mechanical, preferably fibrillating, treatment be subjected. 20. The method according to any one of claims 11 to 19, characterized in that fibrous or fibrous substances are used as the starting product, which by Grinding together with binding agent and / or filling or Aggregates, and possibly with ¥ water, · in Fibrids are transferred. 21. The method according to any one of claims 11 to 19, characterized in that for the preparation of the mixture the fibrids and the binding agent, e.g. cement clinker, are ground together. B098U / 07S9