Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/005—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing gelatineous or gel forming binders, e.g. gelatineous Al(OH)3, sol-gel binders
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators or shrinkage compensating agents
  • C04B22/06—Oxides, Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates

Definitions

• This invention represents an improvement over the known finishing mortars (composed of a filler, a binder, and water) which involves utilizing as the binder a combination of (a) an inorganic gel which is the reaction product of an inorganic base and a metal salt and (b) a water soluble cellulose derivative.
• finishing mortars of the kind here referred to are known as sand-putties.
• Such mortars are characteristic, interalia, by having a'binder content which is low as compared to that of conventional finishing mortars containing mainly lime, lime plus, cement, or gypsum as a binder,
• These sand-putties find use mainly for surface finishing 0n comparatively smooth concrete and light concrete walls. They are pre-fabricated to be ready for use and are stored up in a wet-mixed state.
• finishing mortars have a putty-like character, their thick consistency being due, primarily, to the presence of the cellulose derivative. This involves the drawback of necessitating the content of cellulose derivative or other Watersoluble thickener to be selected higher than would be required from a binding point of view alone. For this reason, said content usually is kept as high as from 0.5% to 1.0% which makes the finishing coat applied to the surface of a building more or less sensitive to water.
• the present invention has for its object to highly improve the water resistance of finishing mortars, or sandputties, of the kind referred to.
• the Water-soluble cellulose derivative is substituted in par by a synthetic inorganic gel produced by reacting an inorganic base with a metal salt and adapted to take over the thickening function of the cellulose derivative.
• This modification also involves further advantages, the most important one being that of imparting to the finishing mortar a more pronounced thixotropic character which will improve the operating or applying characteristics.
• the capacity of spray applicator equipment used has been found to increase by to 50% when spraying a product according to this invention, as compared to products hitherto used.
• the mortar will exhibit excellent properties as regards its capability of filling out relatively deep cavities without shrinking-in and cracking.
• the improved water resistance is due primarily to the reduced content of the water-soluble binder component.
• Such component cannot be omitted entirely, particularly in cases where the finishing mortar is to be used on smooth concrete surfaces or the like, a certain quantity of cellulose derivative or the like being then necessary in order to obtain satisfactory adhesion.
• reaction product obtained by reacting calcium hydroxide with aluminum sulphate.
• This reaction is suitably carried out by pouring a solution of aluminium sulphate into a slurry of slaked lime in water during vigorous stirring thereof.
• a so-called dissolver or any other high-speed mixer equivalent thereto it is preferable to use a so-called dissolver or any other high-speed mixer equivalent thereto, although any other apparatus exerting the required mixing power may be employed.
• the addition of aluminium sulphate may be varied depending on the desired gel viscosity and the desired excess of calcium hydroxide.
• the viscosity of the gel will also depend on its water content.
• the mole ratio of base to the metal salt can range from about 31:1 to about 1:1, and preferably is from about 31:1 to about 7.8: 1.
• this mortar may have added to it between 25 and kg. of a water resistant binder, such as, for example, polyvinyl acetate, co-polymers of vinyl acetate, or acrylate, in the form of an emulsion or a dispersion.
• a water resistant binder such as, for example, polyvinyl acetate, co-polymers of vinyl acetate, or acrylate, in the form of an emulsion or a dispersion.
• the content of cellulose derivative before a possible extra addition of a water resistant binder is still as high as 0.4%.
• this content may be substantially reduced.
• a very satisfactory finishing mortar having high water resistance has been produced with as little as 60 kg. of 6.6% cellulose ether solution and 105 kg. of a polyvinyl acetate dispersion, giving a content of no more than 0.2% water soluble binder.
• the amount of inorganic gel may also be varied. In the example, the gel quantity of the concentration stated amounts to 27% of the filler material quantity.
• the mortar thus obtained may, of course, have a water resistant binder added to it in proportions similar to those of Example A.
• filler materials in the examples described crushed and graded dolomite or limestone, respectively, with a maximum grain size of 0.5 mm. has been used. However, there is no objection to the use of granular materials of different compositions or of larger maximum grain sizes. Thus, it is possible to use filler materials of grain sizes as large as 1 mm., which may be desirable where particularly thick coats of plastering are to be applied.
• the filler material should, however, be graded as well as possible, i.e. it should follow generally accepted rules for the grading of filler material for plasters and mortars.
• the product prepared in accordance with Example C has been found to possess, after setting, a resistance to mechanical wear in a wet state being 5 to times as as that of prior art products of the corresponding
• the use of a gel obtained from calcium hydroxide and aluminium sulphate as described hereinbefore has been found to involve a surprisingly satisfactory effect as regards capacity increase of the spraying equipment used for applying the product. It has been found by repeated tests that the capacity of such applicator equipment was increased by 25 to 50% in terms of litres per minute. The reason for this resides in the pronounced thixotropic properties of the product which enable the material to pass more readily through hoses and nozzles.
• a suitable inorganic gel may be produced by effecting reaction inwater between calcium hydroxide and aluminum sulphate.
• other inorganic bases and metal salts may be used, as well.
• the metallic element of the salt is capable of forming a hydroxide which is difiiculty soluble in water and is prone to forming gels, either in itself or by amphoteric reactions.
• the metal component thereof, besides aluminium, may be zinc, for example and in particular zinc and sulphate.
• ammonium hydroxide may be mentioned.
• the metal salt without any inconvenience, may be a chloride, for example.
• the viscosity of the gel may be specified. Finishing mortars of excellent'qualities have been obtained when using a gel which, at a water content of about 65%, had a viscosity of between 100,000 and 200,000 cp., as measured at +20 C. with a Brookfield viscosimeter equipped with a so-called Helipath Stand.
• the gel of Example A has a viscosity of about 115,000 to 170,000 cp., measured as just described. The viscosity obtained of the gel will depend on the effectiveness of the mixing procedure.
• the method according to claim 1 which comprises additionally admixing a material to impart greater water resistance selected from the group consisting of polyvinyl acetate and the copolymers of vinyl acetate and acrylate in the form of emulsions and dispersions.
• a mortar composition in accordance with claim 4 which additionally contains a material to impart greater water resistance selected from the group consisting of polyvinyl acetate and the copolymers of vinyl acetate and acrylate in the form of emulsions and dispersions.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Dispersion Chemistry (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)

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Cited By (8)

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Citations (2)

• 1966
  • 1966-02-21 GB GB7505/66A patent/GB1139363A/en not_active Expired
  • 1966-02-21 US US528836A patent/US3498809A/en not_active Expired - Lifetime
  • 1966-02-25 FI FI479/66A patent/FI49397B/fi active
  • 1966-02-25 NO NO161857A patent/NO117066B/no unknown

Patent Citations (2)

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