Field of the Invention

The present invention refers to a polymeric mortar formulation. More specifically, it comprises a polymeric mortar composed by a mineral filler, one or more terpolymers associated with one or more polymeric resins with additives and, optionally, silicon nanoparticles and derivatives thereof which modify the mechanical properties of the final product, promoting high adhesion and mechanical strength, high cohesion of the mortar even when exposed to humidity, and accelerated curing.

Background of the Invention

Polymeric mortars consist of substitute products for cement based mortar traditionally used in construction, having a formulation based on acrylic, epoxy or polyurethane resins.

The first report of a formulation similar to the polymeric mortars currently found in the market was published in 1981 in an American magazine (Adhesives Age Magazine, pg 22. October, 1981 ), and consisted of an acrylic resin-based product.

The preparation and the application of the polymeric mortar differs from the conventional mortars, dispensing the preparation or pre-mixture with water, sand, cement or lime on site, once the product is sold ready for use, eliminating variations on how to prepare it. Furthermore, the application of the product is made with an applicator, dispensing the use of trowel and cement mixer.

Another important feature of polymeric mortars is that the joint between the bricks or blocks is given by a far smaller amount of material than the amount required with conventional mortars. While the settlement of a 1 m ² of a wall of brick with six holes requires from 30 to 50 kg of dry cementitious mortar (before mixing water), using polymeric mortar requires only 1 .5 kg of product.

Document BRPI0418333 describes a polymeric mortar composition based on polyurethanes and silanes.

Document BRPI0602016 describes a mortar composition containing the polyester resin and various fillers of natural origin for replacement of Portland cement or mortar.

Document BRPI0100256 describes an adhesive mortar composition based on acrylic resins combined with inert mineral fillers.

Document US2008153942 describes a polymeric concrete based on resins of polymerization (epoxy resins, unsaturated polyester resins, acrylic resins, polyurethane, and silicone) or resins of polycondensation (furanicas resins, phenol-formaldehyde, urea-formaldehyde, melamine-formaldehyde, and amino tri-methylol-melamine resins) resins.

Document US20020103291 describes a mortar composition comprising

Portland cement as the binding agent, and latex based on styrene and butadiene obtained in aqueous emulsion.

Document US20070157854 describes a polymer which coats particles of cement or concrete to form a composite where the polymer forms a continuous matrix, and the particles of cement or concrete are dispersed in this matrix to form a discontinuous phase.

Document BRPI08014571 describes a composition for waterproof bonding and grouting which comprises from 60.0 to 80.0% of "dolomitic polymers," from 6.0 to 9.0% of acrylic emulsion with "50% viscosity," and from 15.0 to 25% of water and additives.

Document BRPI0904087 describes a composition for waterproof bonding and grouting which comprises from 60.0 to 80.0% of "dolomitic polymers," from 12.0 to 17.0% of acrylic emulsion with "50% viscosity," and from 2.0 to 4.0% of emulsion of paraffin and water plus additives.

The prior art describes polymeric mortars using a cementitious-based binding agent added to the formulation, or immediately prior to application or, in other cases, using acrylic or polyurethane resins. Most of prior art mortars have low adhesion to the surface of the bricks/blocks or low cohesion, which consequently leads to low mechanical strength of the adhesive. Additionally, prior art mortars have a long curing time, making it impossible to build very high walls on one day, to avoid loss of plumb and alignment due to deformation of the joints formed by the wet mortar.

Thus, obtaining a polymeric mortar with high adhesion and mechanical resistance to bonding, as well as high cohesion of the mortar when exposed to humidity is the object of the present invention: a polymeric mortar formulation based on one or more terpolymers associated with one or more polymeric resins which, when reacted, change the mechanical properties of the final product. Additionally, the use of terpolymers optionally combined with one or more silicate nanofiller and/or other curing accelerators provide a faster cure of the mortar.

The terpolymers are materials formed by combining three or more monomers, resulting in a product with properties superior to those of the original monomer, having high heat and mechanical resistance, strength and weathering degradation, and showing organized or random distribution of sequences, depending on the monomers used and the participation of each one in polymerization.

Summary of the Invention

It is a characteristic of the invention a polymeric mortar ready for use which does not require the addition of any component.

It is a characteristic of the invention a polymeric mortar that has high bonding power due to presenting in its composition terpolymers reacted with polymeric resins.

It is a characteristic of the invention a polymeric mortar which optionally contains in its formulation silicate nanofillers and/or other curing agents which accelerate the curing of the final product.

It is a characteristic of the invention a polymeric mortar of high durability and resistance to microbial proliferation due to containing silver nanoparticles or other biocides.

Brief Description of the Drawings

Figure 1 shows a graphical representation of the test of compressive strength of the polymeric mortar formulation object of the present invention and prior art mortars. Figure 2 shows a graphical representation of the test of modulus of elasticity (NBR 13279: 2005) of the polymeric mortar object of the present invention and prior art mortars.

Figure 3 shows a graphical representation of the tests of adhesion after cycles of wetting and drying (concrete blocks).

Figure 4 shows a graphical representation of the tests of adhesion after cycles of wetting and drying (tile blocks).

Figure 5 shows the representation of parallel glue of bricks to a wall, being figure (a) an horizontal bonding and figure (b) a vertical bonding.

Detailed Description of the Invention

The composition of polymeric mortar object of the present invention comprises from 60.0 to 90.0% of one or more mineral fillers with a particle size between 0.02 mm (635 mesh) and 3.36 mm (9 mesh), from 1 .0 to 20.0% of one or more multifunctional terpolymers associated with one or more polymeric resins with additives in a proportion of up to 20.0%, and from 0.1 to 8.0% of one or more biocides and 0.1 to 8.0% of one or more biocides.

The terpolymers are preferably selected from the following compositions: styrene/ maleic anhydride/acrylonitrile, vinyl acetate/vinyl ester/butyl acrylate, alpha-methyl styrene/acrylonitrile/styrene, acrylonitrile/styrene/butadiene, poly (alpha-methyl styrene)/butadiene/acrylonitrile, VeoVa/ethylene/methacrylate monomers, Ethylene/propylene/alpha-olefins, divinylbenzene/styrene/glycidyl methacrylate, ethylene/propylene/1 -pentene, ethylene/methyl acrylate/glycidyl methacrylate, being able to be produced by polymerization in bulk, solution, suspension, emulsion or by Ziegler-Natta catalysts.

The inclusion in the formulation of polymeric mortar up to 20.0% of one or more polymeric resins combined with the terpolymer ensures improvement to the composition in the mechanical properties such as oxidation resistance, hardness increase of the mortar after curing, among others.

The polymeric resins show dispersion of copolymers, copolymer emulsions or polymer dispersions.

Optionally, the polymeric resins can have saturated or unsaturated chain. The polymeric resins are selected among the orthophthalic, isophthalic, vinyl ester, bisphenolic polyester, bisphenolic (comprising phenolic resins, resoles and modified, and alkyl phenolic resins) ones, vinyl ester epoxy resins, acrylic resins, methyl methacrylate resins.

Optionally, the mineral fillers are superficially treated with additives to improve compatibility between the filler and the polymeric part of the composition, considering that the fillers have polar surfaces, while polymers have nonpolar surfaces, which makes the connections between them difficult.

Preferably, the fillers are selected from metakaolinite; illite; smectite ((MgCa)O AI2O3S15O10 nH ₂ O), comprising saponite, hectorite, bentonite and montmorillonite; gypsum, limestone comprising calcite (CaCO ₃ ) and dolomite (CaMg (C0 ₃ ) ₂ ); barite (BaSO ₄ ), wollastonite (CaSiO ₃ ), talc (Mg ₆ (Si ₈ O ₂ 0)(OH) ₄ ); agalmatolite; quartz (SiO ₂ ), Zeolite; mica comprising muscovite (K AI ₂ Si ₃ AIOio(OH,F)2, phlogopite, and biotite, pyrophyllite (Si ₄ Oi ₀ )AI ₂ (OH) ₂ ); Kaolinite (AI ₂ Si ₂ O ₅ (OH) ₄ ).

Biocides, which include fungicides, bactericides, bacteriostatic and/or fungistatic, are selected from 2-Bromine-2-nitropropane-1 ,3-diol, ester of p- hydroxybenzoic acid, 2-phenoxyethanol, a combination between isothiazolinones and derivatives of carbamic acids and an halogenated derivative of urea, 5-chloro-2-methyl-4-isothiazolinone/2-methyl-4- isothiazolinone, 5-chloro-2-methyl-4-isothiazolin-3-one/stable aqueous dispersion of carbamate derivatives and isothiazolinones, hemiacetal and isothiazolinones, 1 ,2-benzisothiazolinone, 5-chloro-2-methyl-4- isothiazolinone/2-methyl-4-isothiazolinone, dimethyldimethylhydantoin, isothiazolinones with bromine derivatives, heterocyclic compounds with isothiazolinones and benzimidazole derivatives, 5CI-2-methyl-4-isothiazolin and 2-methyl-4-isothiazolin-3-one, 2,4,4-trichloro-2-hidroxidifenileter, dispersion in polyesters of heterocyclic compounds with isothiazolinones and benzimidazole derivatives.

The fungicides used may optionally contain silver nanoparticles.

Optionally the formulation comprises from 1 .0 to 15.0% of one or more silicate or pozzolan nanoparticles, or other curing accelerators.

The nanoparticles of silicates or pozzolan used in the composition have a particle size between 10 nm and 100 nm, being selected from silicates, nesosilicates (isolated tetrahedra), sorosilicates (tetrahedra in pairs), phyllosilicates (tetrahedra in sheets), inosilicates (tetrahedra in double chain and tetrahedra in single chain) and cyclosilicates (tetrahedra in chain), and the silicates may be calcium, aluminum, potassium, magnesium, calcium hydrate, tricalcium, beryllium, lithium and sodium.

The curing accelerator additives useful for providing drying of the mortar quickly and efficiently are selected from acrylic emulsions, sodium silicate, calcium chloride, sodium bicarbonate, magnesium chloride, ammonium bicarbonate.

Optionally, the composition presents up to 15.0% of adjuvant additives, which may be one or more oligomer, molecule or modified polymer selected from amines, phenols, Butyl/hydroxyl/toluene, triphenyl phosphite, HALS (Hindred Amine Light Stabilizer), benzophenone or benzotriazole derivatives, nickel complexes, 2-(2-hydroxy-3,5-bis(1 ,1 - dimethylbenzyl)phenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5- chlorbenzotriazol, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5- chlorbenzotriazol, 2,6-di-butyl-p-cresol, based on sulfur and phosphor, triesters of phosphoric acid, thioesters and esters of thiodipropionic acid.

Optionally, the composition exhibits anti-foaming agents.

Tests carried out:

The polymeric mortar composition object of the present invention was subjected to physical testing to demonstrate high performance in relation to prior art mortars.

Testing of compressive strength and modulus of elasticity (NBR 13279: 2005) were conducted by the Federal University of Sao Carlos comparing the performance of the formulation of polymeric mortar object of the present invention and prior art mortars.

As shown in Figures 1 and 2, which contains comparative results for prisms composed of different types of blocks, the polymeric mortar object of the present invention obtained superior results of compressive strength in practically all types of blocks tested, without significantly altering the modulus of elasticity of the prisms. These results demonstrate the role of multifunctional terpolymers in the mortar composition, capable of supporting greater loads without causing drastic changes in the masonry capacity of accommodating structural deformation, even with a much finer joint than the one used with the conventional mortar.

The results obtained in Figures 1 and 2 are important for the technical feasibility of the product on a large scale, because masonry with a modulus of elasticity significantly outside the conventional ranges may result in constructive pathologies. The reason would be the incompatibility of the masonry element with various other elements of a building (cement coating, concrete structure, ceramic tiles, etc). Studies performed with polymeric mortars of the prior art, such as mortars based on acrylic resins, resulted in much lower modulus of elasticity than the range found in these tests.

Tests were also conducted at the Falcao Bauer Institute of Quality, according to standard NBR 15575-4/08, proving the compliance of the polymeric mortar object of the present invention in all requirements of the standard, as shown in Tables 1 , 2 and 3.

Table 1 : Results from soft body impact test (internal impact and external impact), according to standard NBR 15575-4/08.

Test Energy (J) Requirement of Result standard NBR

15575-4/08

Impact of soft 2,5 Non-occurrence of No occurrences body - internal failures

impact

Impact of soft 10,0 Non-occurrence of No occurrences body - internal ruptures and impact trespassing

Impact of soft 2,5 Non-occurrence of No occurrences body - external failures, including

impact the coating

Impact of soft 10,0 Non-occurrence of No occurrences body - external ruptures and or

impact trespassing

Table 2: Results obtained in the test of capacity of supporting suspended parts, according to standard NBR 15575-4/08.

Table 3: Results obtained in the leakage test, according to standard NBR 15575-4/08.

Requirement of

Pressure Flow Time

Test standard NBR Result

(Pa) (L/min/m ² ) (h)

15575-4/08 Occurrence of

staining within

Occurrence of 5% of the total

Leakage staining in 2% of

50.0 3.0 7.0 area of the face resistance total area under opposite to the

test incidence of

water

Tests o f tensile strength (NBR 13.528), both in the dry and in saturated state after wetting and drying cycles for different types of blocks, were performed at the Institute for Technological Research (IPT) at Sao Paulo University (USP). The polymeric mortar object of the present invention demonstrated not only resistant to these cycles, but also an improvement in performance after such cycles, as illustrated in graphs 3 and 4. These results can be attributed to multifunctional terpolymers which maintain a strong cohesion among the other components of the formulation, even in extreme humidity condition. By contrast, tests performed with polymeric mortars of the prior art based on acrylic resins showed significant degradation in bond strength after wetting and drying cycles.

The initial adhesion between the bricks to be bonded and the polymeric mortar should have a short period of time, for if the initial adhesion takes a long time to occur, the wall can lose plumb, and therefore cause various pathologies both to the wall itself and to the whole system.

As shown in table 4 and figure 5, in order to check how long the polymeric mortar object of the present invention adheres to the brick, the test of bond strength of the bricks parallel to a wall was carried out, both in horizontal (a) and vertical (b) positions.

As shown in Table 4, the incorporation of terpolymers in the composition of polymeric mortar object of the present invention provided a much faster initial bonding than the bonding with common mortar, and five times faster than the bonding with the polymeric mortar based on acrylic resin.

Table 4: Results of the tests of initial strength of parallel bonding of bricks Samples Initial strength of bonding (min)

Samples with common mortar > 10

Samples with acrylic resin 10

Samples with acrylic resin and

5

terpolymers

Samples with terpolymers 2