Method for manufacturing articles in the form of slabs or blocks with acrylic binder
View Patent ↗In the sector relating to the technology of compaction by means of vacuum vibro-compression for manufacturing slabs or blocks, the organic binder resin consists of an aqueous dispersion of acrylic prepolymer in water and a filler part consists of a hydraulic binder in an amount sufficient to fix wholly or partly the water present in the initial mix; after the vibro-compression step the rough-formed article is subjected to a hardening and curing step in conditions such as to prevent the evaporation of the mix water and subsequently to a heating step so as to obtain crosslinking of the acrylic polymer. If the acrylic binder alone is used, an article with a high degree of porosity is obtained.
1. A method for manufacturing articles in the form of slabs, the method comprising the steps of:
(a) preparing an initial mix, the initial mix consisting of a granulate of a selected and predefined grain size and a binder, wherein
the granulate being chosen from one of a stone material and a ground stone-like materials and comprising one of an inorganic material and a very fine filler,
the binder comprising an aqueous dispersion of an acrylic prepolymer resin in a form of droplets with a diameter of up to about 100 nanometers, and
the filler comprising a hydraulic binder in a sufficient quantity to fix the water present in the aqueous dispersion of the acrylic resin;
(b) depositing the initial mix as a layer of predetermined thickness temporary support or inside a mold;
(c) vacuum vibro-compacting the layer under a predefined vacuum and a predetermined compaction pressure accompanied by a vibratory movement of a predetermined frequency to form a rough-formed article, wherein vacuum, vibration, and compaction are performed simultaneously;
(d) hardening and curing the rough-formed article and binding the water that was added in the aqueous dispersion in the article; and
(e) heating the rough-formed article to 90-120° C. for 5-24 hours and complete filming of the polymer and cross-linking thereof;
wherein step (d) is performed by enclosing said rough-formed article inside a casing of plastic material impermeable to water vapor.
2. Method according to claim 1 , wherein said hydraulic binder is chosen from among cement, gypsum, lime, pozzolana and mixtures thereof.
3. Method according to claim 2 , wherein said hydraulic binder is Portland cement.
4. Method according to claim 2 , wherein said hydraulic binder is a mixture of Portland cement and high-reactivity metakaolin.
5. Method according to claim 4 , wherein said hydraulic binder is a mixture comprising 80-90% by weight of Portland cement and 10-25% of high-reactivity metakaolin.
6. Method according to claim 4 , wherein 2.5-4%, relative to the weight of cement, of a normal superfluidifier, of the type used in cement mixes, is added to said initial mix.
7. Method according to claim 1 , wherein an organofunctional silane is added to the initial mix.
8. Method according to claim 7 , wherein said silane is added in a quantity equal to 1-2% by weight relative to the acrylic resin.
9. Method according to claim 7 , wherein said silane is added to the suspension water of said acrylic resin.
10. Method according to claim 1 , wherein said curing is performed for a week.
11. Method according to claim 1 , wherein if the rough-formed article is in the form of a block, after step (d) a stage involving sawing into slabs is performed.
12. Method according to claim 1 , wherein in order to obtain a porous article, said initial mix is prepared with the sole aqueous dispersion of acrylic prepolymer, dispensing with the addition of a hydraulic binder for fixing the water and envisaging during the process a step for eliminating the water by means of evaporation.
13. A method for manufacturing articles in the form of slabs or blocks, the method comprising the steps of:
preparing an initial mix, the initial mix consisting of a granulate of a selected and predefined grain size and a binder, wherein
the granulate being chosen from one of a stone material and a ground stone-like materials and comprising one of an inorganic material and a very fine filler,
the binder comprising an aqueous dispersion of an acrylic prepolymer resin in a form of droplets with a diameter of up to about 100 nanometers, and
the filler comprising a hydraulic binder in a sufficient quantity to fix the water present in the aqueous dispersion of the acrylic resin;
depositing the first mix as a layer of predetermined thickness on a temporary support or inside a mould;
vacuum vibro-compacting the layer under a predefined vacuum and a predetermined compaction pressure accompanied by a vibratory movement of a predetermined frequency to form a rough-formed article, wherein vacuum, vibration, and compaction are performed simultaneously; and
hardening and curing the rough-formed article and binding the water that was added in the aqueous dispersion in the article.
14. A method for manufacturing articles in the form of slabs from a block, the method comprising the steps of:
(a) preparing an initial mix, the initial mix consisting of a granulate of a selected and predefined grain size and a binder, wherein
the granulate being chosen from one of a stone material and a ground stone-like materials and comprising one of an inorganic material and a very fine filler,
the binder comprising an aqueous dispersion of an acrylic prepolymer resin in a form of droplets with a diameter of up to about 100 nanometers, and
the filler comprising a hydraulic binder in a sufficient quantity to fix the water present in the aqueous dispersion of the acrylic resin;
(b) depositing the initial mix as a layer of predetermined thickness on a temporary support or inside a mold;
(c) vacuum vibro-compacting the layer under a predefined vacuum and a predetermined compaction pressure accompanied by a vibratory movement of a predetermined frequency to form a rough-formed article in a form of the block, wherein vacuum, vibration, and compaction are performed simultaneously;
(d) hardening and curing the rough-formed article and binding the water that was added in the aqueous dispersion in the article;
(e) sawing the block into a plurality of slabs;
(f) heating the slabs to 90-120° C. for 5-24 hours and complete filming of the polymer and cross-linking thereof;
wherein step (d) is performed by enclosing said rough-formed article inside a casing of plastic material impermeable to water vapor.
15. Method according to claim 14 , wherein said hydraulic binder is chosen from among cement, gypsum, lime, pozzolana and mixtures thereof
16. Method according to claim 15 , wherein said hydraulic binder is Portland cement.
17. Method according to claim 15 , wherein said hydraulic binder is a mixture of Portland cement and high-reactivity metakaolin.
18. Method according to claim 17 , wherein said hydraulic binder is a mixture comprising 80-90% by weight of Portland cement and 10-25% of high-reactivity metakaolin.
19. Method according to claim 17 , wherein 2.5-4%, relative to the weight of cement, of a normal superfluidifier, of the type used in cement mixes, is added to said initial mix.
20. Method according to claim 14 , wherein an organofunctional silane is added to the initial mix.
21. Method according to claim 20 , wherein said silane is added in a quantity equal to 1-2% by weight relative to the acrylic resin.
22. Method according to claim 20 , wherein said silane is added to the suspension water of said acrylic resin.
23. Method according to claim 14 , wherein in order to obtain a porous article, said initial mix is prepared with the sole aqueous dispersion of acrylic prepolymer, dispensing with the addition of a hydraulic binder for fixing the water and envisaging during the process a step for eliminating the water by means of evaporation.