Compositions: coating or plastic – Coating or plastic compositions – Inorganic settable ingredient containing
Reexamination Certificate
2000-01-28
2001-10-30
Green, Anthony (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Inorganic settable ingredient containing
C106S725000, C106S806000, C106S808000, C106S823000, C524S003000, C524S004000
Reexamination Certificate
active
06309457
ABSTRACT:
DESCRIPTION OF THE BACKGROUND
Well known techniques exist for preparation of cement-based self-leveling compositions containing mineral aggregates, organic additives, one being a plasticizer, and water. The great advantage of self-leveling compositions normally lies in the ease and rapidity of use, since leveling of such compositions with a straightedge or equivalent means is facilitated or unnecessary.
Thus, there are known:
cement-based self-leveling compositions containing, as plasticizer, for example, a formaldehyde melamine, a melamine derivative or a sulfonated naphthalene. In general, however, because their fluidity exists only for a limited time, such compositions must be placed on the site rapidly after preparation thereof (see, for example, German Utility Model DE 29518306). Methods exist for maintaining the fluidity of such compositions during time, either by adding the plasticizer at timed intervals or by incorporating more plasticizer or by increasing the quantity of mixing water, but for economic and/or technical reasons they are not satisfactory;
cement-based self-leveling compositions containing a special plasticizer which makes it possible to maintain fluidity over time. This may be a plasticizer based on carboxylated vinyl monomers: see, for example, European Patent Applications No. 0725044 and 0753489, wherein the fluidity is maintained for at least 6 hours. The main disadvantage of the compositions described in these two patent applications is one of long setting times. This makes it difficult or even impossible on the following day for persons to walk on toppings manufactured with these compositions for the purpose, for example, of finishing tasks.
The plasticizers known heretofore in the field of self-leveling toppings can be generally classified into four major families:
lignosulfonates;
plasticizers of the polynaphthalenesulfonate type;
plasticizers of the polymelaminesulfonate type;
plasticizers based on carboxylated vinyl monomers and possibly on sulfonated vinyl monomers.
As indicated hereinabove, plasticizers based on carboxylated vinyl monomers are currently preferred, because they lead to maintenance of fluidity over time, although such maintenance of fluidity is often achieved at the expense of short-term strength.
SUMMARY OF THE INVENTION
Surprisingly, there has been discovered a cement-based self-leveling composition which contains, as a plasticizer, an organic compound that does not belong to the aforesaid four plasticizer families: this organic compound is water-soluble or water-dispersible, and contains at least one aminodi (alkylenephosphonic) groups, which may or may not be in salt form, and at least one polyoxyalkyl chain. In addition, the self-leveling composition containing this organic compound has the following decisive advantages:
1) the composition can be prepared in a standard central concrete depot, without modification of such concrete depot, and be delivered ready for use on the site by transit mixers. If necessary, the fluidity of the composition is adjusted by supplementary addition of plasticizer and/or water on the site. In this way homogeneity of the mix is favored;
2) the fluidity of the composition eliminates the traditional operations of spreading, vibrating, leveling with a straightedge or equivalent means, as well as the operation of floating, provided the normal conditions of use are respected by the person skilled in the art. To obtain a flat and smooth surface, it is sufficient to pass a finishing bar and/or a broom over the surface of the fresh product. In addition, the maintenance of this fluidity for a period of time sufficient to place the material (on the order of 2 to 4 hours) and the good kinetics of setting and hardening of the composition permit access of persons on the topping on the day following placement of the composition;
3) the composition, with which a topping can be rapidly completed, makes it possible to achieve great daily productivity, of at least 800 m
2
per day, with a crew of two or three topping workers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
More precisely, the self-leveling composition according to the invention for floor toppings, which composition achieves the aforesaid advantages 1) to 3), is characterized in that it is based on Portland cement (CM I) or on cement mix CM II or CM III (according to Draft European Standard prEN 197-1 of October 1997), and in that it further contains at least sand, water, at least one plasticizer (I) which is a water-soluble or water- dispersible organic compound (I)containing at least one aminodi (alkylenephosphonic) group and at least one salt of compound (I), the compound (I) having the formula:
More precisely, the self-leveling composition according to the invention for floor toppings, which composition achieves the aforesaid advantages 1) to 3), is characterized in that it is based on Portland cement (CM I) or on cement mix CM II or CM III (according to Draft European Standard prEN 197-1 of October 1997), and in that it further comprises at least sand, water, at least one plasticizer (I) which is a water-soluble or water-dispersible organic compound (I) containing at least one aminodi(alkylenephosphonic) group and at least one polyoxyalkyl chain, or at least one salt of compound (I), the said compound (I) having the formula:
in which:
R is a hydrogen atom or a monovalent hydrocarbon group, which may or may not be saturated, containing from 1 to 18 (inclusive) carbon atoms and possibly one or more hetero atoms: preferably R is a hydrogen atom or a monovalent hydrocarbon group, which may or may not be saturated, containing from 1 to 4 carbon atoms;
50% to 100% of the Ri are ethylene, 0 to 50% of the Ri are propylene and 0 to 5% of any other Ri are similar to or different from each other and represent an alkylene such as butylene, amylene, octylene or cyclohexene, or an arylene such as styrene or methylstyrene; these Ri may or may not include one or more hetero atoms;
Q is a hydrocarbon group containing from 2 to 18 (inclusive) carbon atoms and possibly one or more hetero atoms; preferably Q is a hydrocarbon group containing from 2 to 12 (inclusive) carbon atoms, more preferably from 2 to 6 (inclusive) carbon atoms, and even better it represents ethylene or propylene;
A is an alkylidene group containing from 1 to 3 (inclusive) carbon atoms: preferably A represents the methylene group;
the Rj are similar to or different from each other and can be chosen from among:
the A—P03H2 group, wherein A has the meaning indicated hereinabove,
and the group
in which B denotes an alkylene group containing from 2 to 8 (inclusive) carbon atoms: preferably B represents ethylene or propylene and A has the meaning indicated hereinabove;
“n” is an integral number between 20 and 250, terminal groups included;
“r” is the number of [R—O(Ri—O)n] groups carried by the assembly of the Rj,
“q” is the number of [R—O(Ri—O)n] groups carried by Q,
the sum “r+q” is at most equal to 3;
“y” is an integral number equal to 1 or 2.
A detailed description of compounds (I) and of the process for preparation thereof is given in European Patent No. 0663892.
In the context of the present invention, the term self-leveling composition means a composition having a fluidity just before pouring of the floor topping such that, after filling of a reference cone (minor diameter 55 mm, major diameter at the bottom 95 mm, height 70 mm) then withdrawal of the reference cone, the resulting circular free spreading has a diameter at least equal to 15 cm, preferably at least equal to 17 cm, and even better on the order of 23 cm±3 cm.
Advantageously, compound (I) used as plasticizer in the self-leveling composition according to the invention has one or more of the following characteristics:
1—at least 50% of the Ri are ethylene and any other R
i
are propylene;
2—R
j
is chosen from among the —CH
2
—PO
3
H
2
, —C
2
H
4
N(CH
2
—PO
3
H
2
)
2
and —C
3
H
6
N(CH
2
—PO
3
H
2
)
2
groups, which may or may not be in salt form;
3—“n” is between 30 and 150 (terminal groups
Bosc Francois
Chappuis Jacques
Guerinet Jean-Paul
Mosquet Martin
Green Anthony
Lafarge S.A.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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