1. A use for increasing the early mechanical strength of a hydraulic composition of at least one copolymer obtained by polymerization from a mixture of monomers comprising: - at least one anionic monomer (a) comprising a polymerisable unsaturated group and a carboxylic group and - at least one monomer (b) of the following formula (I): H2C = C (– R1) – (CH2)p – O – [ (EO)n – (PO)m ] – H (I) in which: R1 represents a hydrogen atom or a CH3 group, p is equal to 1 or 2, [ (EO)n – (PO)m ] represents a polyalkoxylated chain constituted of ethoxylated units EO and propoxylated units PO, distributed in blocks, alternating or random and m and n represent integers varying between 1 and 250, the sum of m and n being greater than or equal to 10, provided that the molar proportion of the ethoxylated units in the polyalkoxylated chain (n)/(m+n) is strictly lower than 90%.

2. The use according to claim 1, to obtain a compressive strength of the hydraulic composition at 1 day, measured according to EN 12390-3 standard, that is greater than or equal to 155%, in particular greater than or equal to 160%, notably greater than or equal to 170% and more particularly greater than or equal to 180% of the value of the strength of the hydraulic composition devoid of said copolymer(s).

3. The use according to any one of the preceding claims, said copolymer(s) being used in a proportion from 0.05% to 3% by weight, in particular from 0.25% to 2.5% by weight, based on the total weight of the hydraulic composition.

4. The use according to any one of the preceding claims, characterized in that said monomer(s) (b) are of the following formula (I’): H2C = C (– R1) – CH2 – O – [ (EO)n – (PO)m ] – H (I’) in which R1, n and m are as defined in claim 1. 31

5. The use according to any one of the preceding claims, characterized in that said copolymer is obtained from at least one monomer (b) of the following formula (II): H2C = C (– CH3) – CH2 – O – [ (EO)n – (PO)m ] – H (II) in which n and m are as defined in claim 1.

6. The use according to any one of the preceding claims, characterized in that said copolymer is obtained from at least one monomer (b) of the following formula (III): (III) m and n being as defined in claim 1.

7. The use according to any one of the preceding claims, characterized in that the molar proportion of the ethoxylated units EO in the polyalkoxylated chain of said monomer(s) (b) is greater than or equal to 70%, in particular between 70% and 88%, preferably greater than or equal to 75%.

8. The use according to any one of the preceding claims, characterized in that the total number of ethoxylated and propoxylated units (m+n) of the polyalkoxylated chain of the monomer (b) is between 10 and 150, in particular between 18 and 110 and more particularly between 20 and 70.

9. The use according to any one of the preceding claims, characterized in that said monomer(s) (b) represent from 1 mol.% to 50 mol.%, in particular from 5 mol.% to 40 mol.%, notably from 5 mol.% to 30 mol.% and more particularly from 10 mol.% to 20 mol.% of the total mole number of monomers that constitute said copolymer.

10. The use according to any one of the preceding claims, characterized in that said anionic monomer(s) (a) are chosen in the group consisting of acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid and mixtures of these monomers, in particular they are chosen from among acrylic acid, methacrylic acid and their mixtures. 32

11. The use according to any one of the preceding claims, characterized in that said copolymer is obtained by polymerization from a mixture of monomers comprising, in addition to said anionic monomer(s) (a) and said monomer(s) (b) of formula (I), one or several monomer(s) (c) chosen from among: - 2-acrylamido-2-methylpropane sulfonic acid (AMPS), - vinylsufonates, in particular sodium styrene sulfonate, - amines, - the esters having a hydroxyl group, for example methacrylate hydroxyethyl (HEMA), acrylate hydroxyethyl, methacrylate hydroxypropyl and acrylate hydroxypropyl, - alkylene glycol methacrylate or acrylate phosphates, in particular ethylene glycol methacrylate phosphate or again ethylene glycol acrylate phosphate, - acrylamide or methacrylamide, - phosphonic monomers such as vinylphosphonates and alkyl phosphonates, - the macromonomers of the following formula (VI): Ra – [(EO)q – (PO)r – (BO)s] – Ra’ (VI) in which: [(EO)q – (PO)r – (BO)s] represents a polyalkoxylated chain constituted of alkoxylated units, distributed in blocks, alternating or random, chosen from among the ethoxylated units EO, the propoxylated units PO and the butoxylated units BO, q, r and s represent, independently of one another, 0 or an integer varying between 1 and 250, the sum of m, n and p being between 10 and 250, Ra represents a radical chosen in the group consisting of acrylic esters, methacrylic esters and a mixture of these esters and Ra’ represents hydrogen or an alkyl group with from 1 to 4 carbon atoms, - the hydrophobic monomers of the following formula (VII): Rb – [(EO)t – (PO)u – (BO)v] – Rb’ (VII) in which: [(EO)t – (PO)u – (BO)v] represents a polyalkoxylated chain constituted of alkoxylated units, distributed in blocks, alternating or random, chosen from among the ethoxylated units EO, the propoxylated units PO and the butoxylated units BO, t, u and v represent, independently of one another, 0 or an integer varying between 1 and 250, the sum of m, n and p being between 10 and 250, 33 Rb represents a radical chosen in the group consisting of acrylic esters, methacrylic esters and a mixture of these esters and Rb’ represents an alkyl group with from 8 to 40 carbon atoms and - the cross-linking monomers.

FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
USE OF COPOLYMERS FOR IMPROVING THE EARLY-AGE MECHANICAL
RESISTANCE OF A HYDRAULIC COMPOSITION
2. APPLICANT(S)
(a) NAME
(b) NATIONALITY
(c) ADDRESS
COATEX
FRENCH Company
35, RUE AMPÈRE,
F-69730 GENAY,
FRANCE
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL
The following specification describes invention
COMPLETE (√)
The following specification particularly describes the invention
and the manner in which it is to be performed
4. DESCRIPTION (Description shall start from next page)
5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble – “I/We claim”
on separate page)
6. DATE AND SIGNATURE ( to be given on the last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on the separate page)
Note:
*Repeat boxes in case of more than one entry
*To be signed by the applicant(s)or the authorized registered patent agent
*Name of the applicant should be given in full, family name in the beginning
*Complete address of the applicant should be given stating with postal index no. / code, state and country
*Strike out the column which is/are not applicable
This form is digitally signed.
2
The present invention relates to the field of hydraulic compositions, such as concrete and
mortar compositions. More particularly, it relates to the use of specific copolymers for
improving the early mechanical strength of hydraulic compositions.
Such hydraulic compositions are intended for all construction markets.
Hydraulic compositions generally comprise various chemical additives intended to modulate
their properties. Among these, the agents called “water reducers,” also called “dispersing
agents,” “fluidifying agents,” “plasticizers” or “superplasticizers,” are well known and have
been used for many years. These dispersants lead to reduced water content in hydraulic
compositions, which improves the performances of these compositions and notably their
mechanical strength.
For example, carboxylic comb polymers have been developed as dispersing agents. In a
general manner, these polymers generally have a (meth)acrylic backbone and side chains
terminated by hydrophilic groups, for example polyoxyalkylated side groups.
Accordingly, document CN 1148329 C proposes, as dispersing agents for cements,
copolymers obtained by polymerization from a monocarboxylic acid monomer, such as
(meth)acrylic acid and a polyalkylene glycol ether monomer in which the proportion of
ethoxylated units is at least 90 mol.% of all of the alkoxylated units, preferably a
polyethylene glycol ether.
Document JP 2006/282414 relates to an agent for developing high resistance for cement. It
contains, as essential components, (a) glycerol or a glycerol derivative and (b) a
polycarboxylic acid copolymer with a polyoxyalkylene compound on a side chain.
Document US 6,211,317 describes emulsion copolymers of unsaturated carboxylic acid
derivatives, of alkenyl oxyalkylene glycol ethers, of unsaturated dicarboximides or of amides
and vinyl monomers. They are described for their use as additives for hydraulic binders, in
particular for cement.
3
On the other hand, the workability of compositions, for example concrete compositions,
increases with their water content. So it is essential to have good initial workability or fluidity
of the hydraulic composition, for example of the concrete, in so far as this property
conditions its use, for example for filling a shuttering. Workability may be evaluated by
measuring the slump, in accordance with EN 12350-2 standard.
Consequently, generally, during the formulation of a hydraulic composition, the aim is to find
a compromise between the mechanical properties and the workability of the hydraulic
composition.
Better mechanical strength is one of the particularly desired properties during the evaluation
of hydraulic compositions. Mechanical strength in hydraulic compositions may be measured
at different times, for example at 1 day, at 7 days or at 28 days, where time T0 corresponds to
the preparation of the hydraulic composition. In the scope of the present invention, the
interest is more particularly early mechanical strength. High early mechanical strength is
particularly desirable in the case of concreting in cold weather or also for fast onsite
demolding.
This “early mechanical strength” property, also called “compressive strength at 1 day,” is
defined as the change in compressive strength as a function of the age of preparation of the
hydraulic composition, in the zone T0 to T = 1 day following the preparation of the hydraulic
composition.
The present invention targets precisely improving the early strength, notably at 1 day, for
hydraulic compositions without altering their initial fluidity or workability.
It thus relates, according to a first of its aspects, to the use for increasing the early mechanical
strength of a hydraulic composition, notably at 1 day, of at least one copolymer obtained by
polymerization from a mixture of monomers comprising:
- at least one anionic monomer (a) comprising a polymerizable unsaturated group and
a carboxylic group and
- at least one monomer (b) of the following formula (I):
H2C = C (– R1) – (CH2)p – O – [(EO)n – (PO)m] – H (I)
4
in which:
R1 represents a hydrogen atom or a CH3 group,
p is equal to 1 or 2,
[(EO)n – (PO)m] represents a polyalkoxylated chain constituted of ethoxylated units
EO and propoxylated units PO, distributed in blocks, alternating or random and
m and n represent integers varying between 1 and 250, the sum of m and n being
greater than or equal to 10, provided that the molar proportion of the ethoxylated units
in the polyalkoxylated chain (n)/(m+n) is strictly lower than 90%.
The copolymers used according to the invention, as defined above, comprising at least some
units derived from anionic monomers (a) and some units derived from monomers (b) of
formula (I), are denoted more simply in the rest of the text as “copolymers according to the
invention.”
In the scope of the present invention, the “early” mechanical strength is more particularly
understood to be the compressive strength at 24 hours (± 15 minutes) after the preparation of
the hydraulic composition. The compressive strength at 1 day may be measured according to
EN 12390-3 standard.
“Improving” or ”increasing” the early mechanical strength is understood more particularly, in
the scope of the invention, by the use of the copolymer according to the invention as
admixture in a hydraulic composition, to mean the fact of accessing increased compressive
strength at 1 day (measured according to EN 12390-3 standard) of at least 4%, in particular of
at least 4.5%, notably of at least 10%, preferably of at least 15% and more preferentially of at
least 20%, by comparison with the strength value obtained with the use as admixture in a
same hydraulic composition of a copolymer, not in accordance with the invention, of a
similar composition with the exception of the fact that the polyalkoxylated chain of type (b)
monomer units is a polyethylene glycol chain (100 mol.% of ethoxylated units EO).
The use of copolymers according to the invention allows faster development of early
mechanical strength in hydraulic compositions that incorporate it. In other words, such
copolymers may improve the short-term mechanical strength (“early age”), notably at
1 day, of the hydraulic compositions in which they are used.
5
As illustrated in the examples that follow, the copolymers according to the invention
advantageously allow production of high early resistances, notably at 1 day.
More particularly, the use of a copolymer according to the invention in a hydraulic
composition, for example a concrete composition, produces a compressive strength at
1 day (measured according to EN 12390-3 standard) of the admixtured hydraulic composition
according to the invention greater than or equal to 155% of the value of the strength of the
hydraulic composition devoid of copolymer according to the invention. In particular, the
compressive strength at 1 day may be greater than or equal to 160%, notably greater than or
equal to 170%, or even greater than or equal to 180% of the value of the strength of the
hydraulic composition devoid of copolymer according to the invention.
The use of copolymers according to the invention proves, for example, to be particularly
advantageous for concreting. The increased short-term mechanical resistances of the
hydraulic composition, for example concrete, also allows for faster removal from shutterings
and demolding.
Moreover, advantageously, this increase in early mechanical strength is not done to the
detriment of other performances of the hydraulic composition, notably its initial fluidity or
workability.
Other characteristics, advantages and methods of application of the use of the copolymers
according to the invention will better emerge upon reading the description and the example
that will follow, given for illustration and in a non-limiting manner.
In the rest of the text, the expressions “comprised between … and …,” “ranging from …
to …” and “varying from … to …” are equivalent and understood to mean that the limits are
included, unless indicated otherwise.
Unless indicated otherwise, the expression “including/comprising a” must be understood as
“including/comprising at least one.”
6
Copolymers according to the invention
As indicated previously, the present invention uses copolymers obtained by the
polymerization of at least:
- one or more anionic monomer(s) comprising a polymerizable unsaturated group and
a carboxylic group, denoted “monomer(s) (a)” in the rest of the text and
- one or more monomer(s) of the following formula (I), denoted “monomer(s) (b)” in
the rest of the text,
H2C = C (– R1) – (CH2)p – O – [(EO)n – (PO)m] – H (I)
in which:
R1 represents a hydrogen atom or a CH3 group,
p is equal to 1 or 2,
[(EO)n – (PO)m] represents a polyalkoxylated chain constituted of ethoxylated
units EO and propoxylated units PO, distributed in blocks, alternating or random and
m and n represent integers varying between 1 and 250, the sum of m and n being
greater than or equal to 10, provided that the molar proportion of the ethoxylated units
in the polyalkoxylated chain (n)/(m+n) is strictly lower than 90%.
The copolymers used according to the invention may optionally comprise other
polymerizable monomers. The optional monomers optionally forming part of the composition
of a copolymer according to the invention may be varied in nature, as described in the rest of
the text.
In particular, said anionic monomers (a) and said monomers (b) of formula (I) may represent
more than 80 mol.%, in particular more than 90 mol.% and more particularly more than
95 mol.% of the total number of moles of monomers that constitute the copolymer.
According to one variant of embodiment, the copolymer used according to the invention is
formed only of units deriving from monomers (a) and (b). In other words, the copolymer may
be obtained by polymerization from a mixture of monomers formed from one or more anionic
monomer(s) (a) and from one or more monomer(s) (b) of formula (I). The distribution of the
units deriving from monomers (a) and those deriving from monomers (b) in the copolymer
according to the invention may be blocks, alternate or random. According to one
7
embodiment, it is a random or alternate distribution. According to another embodiment, it is a
block distribution.
The copolymer used according to the invention may be obtained by polymerization from a
mixture of monomers consisting in:
- at least one anionic monomer (a) comprising a polymerizable unsaturated group and a
carboxylic group and
- at least one monomer (b) of formula (I):
H2C = C (– R1) – (CH2)p – O – [ (EO)n – (PO)m ] – H (I)
in which:
R1 represents a hydrogen atom or a CH3 group,
p is equal to 1 or 2,
[(EO)n – (PO)m] represents a polyalkoxylated chain constituted of ethoxylated units
EO and propoxylated units PO, distributed in blocks, alternating or random and
m and n represent integers varying between 1 and 250, the sum of m and n being
greater than or equal to 10, provided that the molar proportion of the ethoxylated units
in the polyalkoxylated chain (n)/(m+n) is greater than or equal to 70% and strictly
lower than 90%.
The amounts of monomers (a) and (b) used then correspond to 100% by weight of the total of
the amounts of monomers forming the copolymer used according to the invention.
Anionic monomer (a) having a polymerizable unsaturated group and a carboxylic group.
The anionic monomers (a) entering in the composition of the copolymer used according to
the invention may be more particularly chosen from acrylic acid, methacrylic acid, maleic
acid, itaconic acid, crotonic acid and the mixtures of these monomers.
Said monomer(s) (a) may be in acid form, for example carboxylic acid and/or in salt form, for
example carboxylate salt.
8
It is understood that a single monomer or a mixture of several different monomers (a) may
enter in the composition of the copolymer according to the invention. For example, this may
be a mixture of monomers of acrylic acid and monomers of methacrylic acid or also of a
mixture of monomers of maleic acid, acrylic acid and methacrylic acid.
According to one specific embodiment, the copolymer used according to the invention is
formed from at least acrylic acid and/or methacrylic acid, in particular of at least acrylic acid
(AA).
According to one variant of embodiment, said anionic monomer(s) (a) entering in the
composition of the copolymer used according to the invention are chosen from acrylic acid,
methacrylic acid and their mixture.
According to a specific embodiment, said anionic monomer(s) (a) may represent from
50 mol.% to 99 mol.%, in particular from 60 mol.% to 95 mol.%, notably from 70 mol.% to
95 mol.% and more particularly from 80 mol.% to 90 mol.% of the total number of moles of
de monomers that constitute the copolymer according to the invention.
Monomer (b) of formula (I)
As indicated previously, the monomers (b) entering in the composition of the copolymer used
according to the invention correspond to the following formula (I):
H2C = C (– R1) – (CH2)p – O – [(EO)n – (PO)m] – H (I)
in which:
R1 represents a hydrogen atom or a CH3 group,
p is equal to 1 or 2,
[(EO)n – (PO)m] represents a polyalkoxylated chain constituted of ethoxylated units
EO and propoxylated units PO and
m and n represent integers varying between 1 and 250, the sum of m and n being
greater than or equal to 10, provided that the molar proportion of the ethoxylated units
in the polyalkoxylated chain (n)/(m+n) is strictly lower than 90%.
9
“Polyalkoxylated” chain is understood to mean a poly(alkylene glycol) chain. “Poly(alkylene
glycol)” is understood to mean a polymer of an alkylene glycol derived from an olefin oxide.
The poly(alkylene glycol) chain of monomer (b) is formed of ethoxylated units (or “ethyleneoxy”),
denoted “EO,” of formula –CH2-CH2-O- and of propoxylated units (or “propyleneoxy”),
denoted “PO,” of formula –CH2-CH(CH3)-O-.
The schematic representation “[(EO)n – (PO)m]” does not in any way presume the order of
ethoxylated and propoxylated units of the polyalkoxylated chain. Indeed, the polyalkoxylated
chain may present a distribution of block, random or alternate EO and PO units.
According to a specific embodiment, the EO and PO units are distributed in blocks.
In particular, the polyalkoxylated chain of the monomer (b) may be diblock and be formed of
a polyoxyethylene block and a polyoxypropylene block.
According to one variant of embodiment, p in the previously cited formula (I) equals 1.
In other words, according to this variant of embodiment, said monomer(s) (b) entering in the
composition of the copolymer according to the invention correspond to the following formula
(I’):
H2C = C (– R1) – CH2 – O – [(EO)n – (PO)m] – H (I’)
in which R1, n and m are as defined previously.
According to a specific embodiment, the copolymer used according to the invention is
formed from at least one previously cited monomer (b) of formula (I) or (I’), in which R1
represents a methyl group.
In particular, according to a specific embodiment, the copolymer used according to the
invention is obtained from at least one monomer (b) of the following formula (II):
H2C = C (–CH3) – CH2 – O – [(EO)n – (PO)m] – H (II)
in which n and m are as defined previously.
10
As indicated previously, the schematic representation “[(EO)n – (PO)m]” does not in any way
presume the order of ethoxylated and propoxylated units of the polyalkoxylated chain. The
polyalkoxylated chain may present a distribution of block, random or alternate EO and PO
units, in particular block units.
According to a specific embodiment, the copolymer used according to the invention is
obtained from at least one monomer (b) of the following formula (III):
(III)
m and n being as defined previously.
In the previously cited formula (III), the polyalkoxylated chain is formed of a first
polyoxyethylene block and of a second polyoxypropylene block.
According to one variant of embodiment, p in the previously cited formula (I) equals 2.
In other words, according to this variant of embodiment, said monomer(s) (b) entering in the
composition of the copolymer according to the invention correspond to the following formula
(I’’):
H2C = C (– R1) – CH2 – CH2 – O – [(EO)n – (PO)m] – H (I’’)
in which R1, n and m are as defined previously.
According to a specific embodiment, the copolymer used according to the invention is
formed from at least one previously cited monomer (b) of formula (I’’), in which R1
represents a methyl group.
In particular, according to a specific embodiment, the copolymer used according to the
invention is formed from at least one monomer (b) of the following formula (IV):
H2C = C (–CH3) – CH2 – CH2 – O – [(EO)n – (PO)m] – H (IV)
in which n and m are as defined previously.
11
As indicated previously, the schematic representation “[(EO)n – (PO)m]” does not in any way
presume the order of ethoxylated and propoxylated units of the polyalkoxylated chain. The
polyalkoxylated chain may present a distribution of block, random or alternate EO and PO
units, in particular block units.
According to a specific embodiment, the copolymer used according to the invention is
obtained from at least one monomer (b) of the following formula (V):
H2C = C (–CH3) – CH2 – CH2 – O – (EO)n – (PO)m – H (V)
m and n being as defined previously.
In the previously cited formula (V), the polyalkoxylated chain is formed of a first
polyoxyethylene block and of a second polyoxypropylene block.
In the same way as for anionic monomers (a), it is understood that a single monomer or a
mixture of several different monomers (b) may enter in the composition of the copolymer
used according to the invention.
Thus, according to a specific embodiment, the copolymer according to the invention is
obtained from at least a mixture of at least one monomer (b1) of formula (I) in which R1
represents a hydrogen atom and of at least one monomer (b2) of formula (I) in which R1
represents a methyl group.
In particular, the copolymer according to the invention may be obtained from at least a
mixture of at least one monomer (b1’) of previously cited formula (I’) in which R1 represents
a hydrogen atom and of at least one monomer (b2’) of previously cited formula (I’) in which
R1 represents a methyl group (in other words, a monomer (b2’) of previously cited formula
(II)).
In the scope of this specific embodiment, said monomer(s) (b1’) and said monomer(s) (b2’)
entering in the composition of the copolymer according to the invention may be used in a
molar ratio of monomer(s) (b1’)/monomer(s) (b2’) ranging from 10 to 0.01, in particular from
1 to 0.1.
12
According to another specific embodiment, the copolymer according to the invention may be
obtained from at least a mixture of at least one monomer (b1’) of previously cited formula (I’)
and of at least one monomer (b2’’) of previously cited formula (I’’). In particular, the
copolymer according to the invention may be obtained from at least a mixture of at least one
monomer (b1’) of previously cited formula (I’) in which R1 represents a methyl group (in
other words, a monomer (b1’) of previously cited formula (II)) and of at least one monomer
(b2’’) of previously cited formula (I’’) in which R1 represents a methyl group (in other words,
a monomer (b2’’) of previously cited formula (IV)).
According to an essential characteristic of said monomer(s) (b) entering in the composition of
the copolymer according to the invention, the molar proportion of ethoxylated units EO in the
polyalkoxylated chain (i.e. (n)/(m+n) in the previously cited formula (I), (I’), (II) or (III)) is
strictly lower than 90%.
According to a specific embodiment, the molar proportion of ethoxylated units EO in the
polyalkoxylated chain is greater than or equal to 70%.
In particular, the molar proportion of ethoxylated units EO in the polyalkoxylated chain may
be comprised between 70% and 88%, in particular be greater than or equal to 72%, and more
particularly greater than or equal to 75%.
According to a specific embodiment, the molar proportion of ethoxylated units EO in the
polyalkoxylated chain may be lower than or equal to 85%, in particular lower than or equal to
80%.
According to another specific embodiment, the molar proportion of ethoxylated units EO in
the polyalkoxylated chain may be greater than or equal to 80%, in particular greater than or
equal to 85%. It may for example be about 88%.
The molar ratio between the ethoxylated units and the propoxylated units of the
polyalkoxylated chain may be more particularly comprised between 2.5 and 8, in particular
between 2.8 and 7.5, notably between 6 and 7.5.
13
As indicated previously, the total number of ethoxylated and propoxylated units of the
polyalkoxylated chain (in other words the sum of m and n) of the monomer (b) is greater than
or equal to 10.
According to a specific embodiment, it may be comprised between 10 and 150, in particular
between 18 and 110 and more particularly between 20 and 70.
The polyalkoxylated chain of monomer (b) according to the invention may accordingly have
a number-average molar mass comprised between 450 g/mol and 7,500 g/mol, in particular
between 900 g/mol and 5,500 g/mol and more particularly between
1,000 g/mol and 3,500 g/mol.
It is understood that the different variants and specific embodiments given above may be
combined, in so far as possible, to define other specific variants or embodiments.
The monomers (b) may be prepared by techniques known to the person skilled in the art,
making the desired polyalkoxylated chain grow by polymerization from monomers of
ethylene oxide and propylene oxide on an allyl or methallyl alcohol.
According to a specific embodiment, said anionic monomer(s) (b) may represent from
1 mol.% to 50 mol.%, in particular from 5 mol.% to 40 mol.%, notably from 5 mol.% to
30 mol.% and more particularly from 10 mol.% to 20 mol.% of the total number of moles of
monomers that constitute the copolymer used according to the invention.
Said monomer(s) (b) may be presented in different forms, notably in solid form, in particular
in powder or flake form, or in liquid form (liquid formed of monomers (b) or aqueous
solution of monomers (b)).
In particular, the monomers (b) are water-soluble.
Preferably, said monomer(s) (b) are used in liquid form, in particular in aqueous solution, this
form being particularly appropriate for the synthesis of the copolymer used according to the
invention.
14
The molar ratio between said anionic monomer(s) (a) and said monomer(s) (b) entering in the
composition of the copolymer according to the invention may be more particularly comprised
between 1 and 99, in particular between 2.3 and 19 and more particularly between 4 and 9.
Optional monomers
As indicated previously, the copolymer used according to the invention may be obtained by
polymerization from a mixture of monomers comprising, in addition to said monomer(s) (a)
and said monomer(s) (b), one or more additional monomer(s), different than monomers (a)
and (b) denoted “monomer(s) (c)” in the rest of the text.
The additional monomers (c) may be more particularly chosen from:
- 2-acrylamino-2-methylpropane sulfonic acid (AMPS),
- vinylsulfonates, in particular sodium styrene sulfonate,
- amines,
- esters having a hydroxyl group, for example hydroxyethyl methacrylate (HEMA),
hydroxyethyl acrylate, hydroxypropyl methacrylate and hydroxypropyl acrylate,
- alkylene glycol acrylate or methacrylate phosphates, in particular ethylene glycol
methacrylate phosphate or again ethylene glycol acrylate phosphate,
- acrylamide or methacrylamide,
- phosphonic monomers, such as vinylphosphonates and alkyl phosphonates,
- macromonomers of following formula (VI):
Ra – [(EO)q – (PO)r – (BO)s] – Ra’ (VI)
in which:
[(EO)q – (PO)r – (BO)s] represents a polyalkoxylated chain constituted of alkoxylated
units, distributed in blocks, alternated or random, chosen from ethoxylated units EO,
propoxylated units PO and butoxylated units BO,
q, r and s represent, independently of one another, 0 or an integer varying between 1
and 250, the sum of m, n and p being comprised between 10 and 250,
Ra represents a radical chosen from the group consisting of acrylic esters, methacrylic
esters and a mixture of these esters and
Ra’ represents hydrogen or an alkyl group with from 1 to 4 carbon atoms,
- the hydrophobic monomers of following formula (VII):
Rb – [(EO)t – (PO)u – (BO)v] – Rb’ (VII)
in which:
15
[(EO)t – (PO)u – (BO)v] represents a polyalkoxylated chain constituted of alkoxylated
units, distributed in blocks, alternated or random, chosen from ethoxylated units EO,
propoxylated units PO and butoxylated units BO,
t, u and v represent, independently of one another, 0 or an integer varying between
1 and 250, the sum of m, n and p being comprised between 10 and 250,
Rb represents a radical chosen from the group consisting of acrylic esters, methacrylic
esters and a mixture of these esters and
Rb’ represents an alkyl group with from 8 to 40 carbon atoms and
- cross-linking monomers.
According to a specific embodiment, in the previously cited formula (VI), s equals 0 and q
and r represent an integer varying between 1 and 250, for example between 10 and 150 or
between 10 and 100.
According to a specific embodiment, in the previously cited formula (VII), v equals 0 and t
and u represent an integer varying between 1 and 250, for example between 10 and 150 or
between 10 and 100.
Said additional monomer(s) (c) may also be chosen from cross-linking monomers.
The copolymer according to the invention may, for example, include a single
cross-linking monomer. According to another embodiment, it includes two different crosslinking
monomers.
The cross-linking monomer may have hydrophilic, hydrophobic or amphiphilic character.
Examples of these compounds include di(meth)acrylate compounds such as
polyalkylene glycol di(meth)acrylate, notably polypropylene glycol di(meth)acrylate,
ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate,
triethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate,
1,6-butylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate,
neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, but also
2,2'-bis(4-(acryloxy-propyloxyphenyl)propane, 2,2'-bis(4-(acryloxydiethoxy-phenyl)propane
and zinc acrylate, tri(meth)acrylate compounds such as trimethylolpropane tri(meth)acrylate,
trimethylolethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate and
16
tetramethylolmethane tri(meth)acrylate, tetra(meth)acrylate compounds such as
ditrimethylolpropane tetra(meth)acrylate, tetramethylolmethane tetra(meth)acrylate and
pentaerythritol tetra(meth)acrylate, hexa(meth)acrylate compounds such as dipentaerythritol
hexa(meth)acrylate, penta(meth)acrylate compounds such as dipentaerythritol
penta(meth)acrylate, allyl compounds such as allyl (meth)acrylate, diallylphthalate,
diallyl itaconate, diallyl fumarate and diallyl maleate, polyallyl sucrose ethers with from 2 to
8 groups per molecule, polyallyl pentaerythritol ethers such as pentaerythritol diallyl ether,
pentaerythritol triallyl ether and pentaerythritol tetraallyl ether, polyallyl trimethylolpropane
ethers such as diallyl trimethylolpropane ether and triallyl trimethylolpropane ether. Other
polyunsaturated compounds include divinyl glycol, divinyl benzene, divinylcyclohexyl and
methylenebisacrylamide.
According to another aspect, the cross-linking monomers may be prepared by an
esterification reaction of a polyol with an unsaturated anhydride such as maleic anhydride,
itaconic anhydride or (meth)acrylic anhydride or by an addition reaction with an isocyanate
such as 3-isopropenyl-dimethylbenzene isocyanate.
The following compounds may be used to obtain cross-linking monomers: polyhaloalkanols
such as 1,3-dichloroisopropanol and 1,3-dibromoisopropanol, haloepoxyalkanes such as
epichlorohydrin, epibromohydrin, 2-methyl epichlorohydrin and epiiodohydrin, polyglycidyl
ethers such as 1,4-butanediol diglycidyl ether, glycerin-1,3-diglycidyl ether, ethylene glycol
diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether,
neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, bisphenol
A-epichlorohydrin epoxy resin and mixtures.
According to a specific embodiment, the cross-linking monomer is chosen from
(meth)acrylates with at least two double bonds with polymerizable ethylenic unsaturation (for
example prepared by esterification of (meth)acrylic acid with a linear or branched polyol with
from 2 to 12 carbon atoms and at least two hydroxyl groups), polyalkenyl-polyethers with at
least two double bonds with polymerizable ethylenic unsaturation (for example prepared by
etherification of alkenyl halides with a linear or branched polyol with from 2 to 12 carbon
atoms and at least two hydroxyl groups) and the mixtures of these cross-linking monomers.
17
According to an embodiment of the present invention, the copolymer includes two
cross-linking monomers:
- said first cross-linking monomer being a (meth)acrylate with at least two double
bonds with polymerizable ethylenic unsaturation (for example prepared by
esterification of (meth)acrylic acid with a linear or branched polyol with from 2 to 12
carbon atoms and at least two hydroxyl groups) and
- said second cross-linking monomer being a polyalkenyl-polyether with at least two
double bonds with polymerizable ethylenic unsaturation (for example prepared by
etherification of alkenyl halides with a linear or branched polyol with from 2 to 12
carbon atoms and at least two hydroxyl groups).
According to another embodiment, the copolymer includes two cross-linking monomers with
different natures, for example trimethylolpropane tri(meth)acrylate (TMPTA or TMPTMA)
and trimethylolpropane diallyl ether (TMPDAE).
It is understood that the content of additional monomer(s) used, for example of
cross-linking monomer(s), is adjusted so as not to alter the desired properties of the
copolymer.
In a general manner, said additional monomer(s) (c) may represent less than 20 mol.%, in
particular less than 15 mol.%, notably less than 10 mol.% and more particularly less than
5 mol.% of the total number of moles of monomers that constitute the copolymer according
to the invention.
The different embodiments described for each of the monomers entering in the composition
of the copolymer used according to the invention may be combined.
According to a specific embodiment, the copolymer used according to the invention may thus
be obtained by polymerization from a mixture of monomers comprising, or even formed by:
- one or more anionic monomer(s) (a) chosen from acrylic acid, methacrylic acid and
their mixtures, in particular acrylic acid and
18
- one or more monomer(s) (b) of previously cited formula (I’), in particular of
previously cited formula (II), in which the ethoxylated and propoxylated units are
more particularly distributed in blocks.
According to a specific embodiment, the copolymer according to the invention comprises at
least units deriving from acrylic acid and units deriving from a monomer of formula (II), in
particular of formula (III) as described previously.
According to a first specific embodiment, the copolymer used according to the invention is
obtained by the polymerization of at least:
- 50 to 99 mol.% of at least one anionic monomer (a), in particular as defined
previously and
- 1 to 50 mol.% of at least one monomer (b) of formula (I), in particular as defined
previously,
the molar percentages of each monomer being expressed with respect to the total number of
moles of monomers that constitute the copolymer.
According to a second specific embodiment, the copolymer used according to the invention is
obtained by the polymerization of at least:
- 70 to 95 mol.% of at least one anionic monomer (a), in particular as defined
previously and
- 5 to 30 mol.% of at least one monomer (b) of formula (I), in particular as defined
previously,
the molar percentages of each monomer being expressed with respect to the total number of
moles of monomers that constitute the copolymer.
According to a third specific embodiment, the copolymer used according to the invention is
obtained by the polymerization of at least:
- 80 to 90 mol.% of at least one anionic monomer (a), in particular as defined
previously and
- 10 to 20 mol.% of at least one monomer (b) of formula (I), in particular as defined
previously,
19
the molar percentages of each monomer being expressed with respect to the total number of
moles of monomers that constitute the copolymer.
According to these three specific embodiments, the sum of molar percentages of monomers
(a) and monomers (b) is equal to 100%. In other words, the copolymer is, according to these
three embodiments of the invention, formed only of units deriving from monomers (a) and
(b) in the molar proportions indicated.
The copolymer according to the invention may present a weight-average molecular
mass Mw comprised between 15,000 g/mol and 250,000 g/mol, in particular
between 20,000 g/mol and 200,000 g/mol and more particularly between 25,000 g/mol and
175,000 g/mol.
The weight-average molecular mass or Mw may be determined by Steric Exclusion
Chromatography (SEC), as described more precisely in the example that follows.
The copolymer used according to the invention may be presented in the form of salts,
stoichiometric or not, mixed or not, and constituted with alkali metals, alkline earth metals,
amines or quaternary ammoniums.
According to a specific embodiment, the copolymer according to the invention is found in
acidic form.
According to another embodiment, the copolymer according to the invention is found in
neutralized form.
According to yet another embodiment, the copolymer according to the invention is found in
partially or totally neutralized form.
According to a specific embodiment, the copolymer is neutralized by an ion chosen in the
group consisting of potassium ion, sodium ion, lithium ion, calcium ion, magnesium ion,
ammonium ion, diethanolammonium ion and a mixture of these ions.
20
The copolymer according to the invention may be prepared by conventional polymerization
techniques from monomers (a), (b) and optionally (c).
According to one variant of embodiment, the copolymer according to the invention may be
obtained by free radical polymerization, notably by controlled free radical polymerization.
According to another of its aspects, the invention relates to a copolymer as defined
previously, in particular obtained by polymerization from a mixture of monomers
comprising:
- at least one anionic monomer (a) as described above and
- at least one monomer (b) of formula (I) as described above, for which the
polyalkoxylated chain has a molar proportion of ethoxylated units greater than or
equal to 70% and strictly lower than 90%.
Use for increasing the early strength of hydraulic compositions
As mentioned previously, the copolymers according to the invention prove to be particularly
effective for increasing the early mechanical strength of hydraulic compositions.
Accordingly, the invention relates to a method for increasing the early mechanical strength,
and notably at 1 day, of a hydraulic composition comprising the addition to said hydraulic
composition of at least one copolymer as described previously.
The admixed hydraulic composition according to the invention has faster development of
early mechanical strength, notably at 1 day.
Advantageously, the strength at 1 day (measured according to EN 12390-3 standard) of the
hydraulic composition admixed according to the invention may be greater than or equal to
155% of the value of the strength of the hydraulic composition devoid of copolymer
according to the invention. In particular, it may be greater than or equal to 160%, notably
greater than or equal to 170%, and more particularly greater than or equal to 180% of the
value of the strength of the hydraulic composition devoid of copolymer according to the
invention.
21
Accordingly, the invention relates to the use of at least one copolymer as described
previously as an admixture in a hydraulic composition, for example a concrete composition,
for increasing the rate of development of the early mechanical strength, notably at 1 day.
The admixture according to the invention may be used in different forms, in particular in
liquid form. It may notably be presented in the form of an aqueous solution of one or more
copolymer(s) according to the invention, of which the solids content may be more
particularly comprised between 25% and 65%, for example between 30% and 60%.
According to another of its aspects, the invention relates to the use of a copolymer as defined
previously as a water reducing agent in a hydraulic composition.
It also relates to a water reducing agent for hydraulic compositions comprising, or even
consisting of, one or more copolymer(s) as defined previously.
The water reducing agent according to the invention, as well as allowing a reduction of the
amount of water in the hydraulic composition in which it is used, advantageously allows the
faster development of early mechanical strength, notably at 1 day.
According to yet another of its aspects, the invention relates to a hydraulic composition
comprising at least one copolymer as described hereinabove.
The hydraulic compositions may be of diverse natures. They may be intended for
manufacturing a grout, a coating, an adhesive, a concrete or a mortar. They may comprise
impurities, for example clays. These compositions may notably comprise latexes, fibers,
organic granulates, inorganic granulates, fillers or charges and/or CaCO3.
The hydraulic compositions, for example concrete and mortar compositions, may comprise as
hydraulic binder different types of cement, such as for example the cements CEM I, CEM II,
CEM III, CEM IV and CEM V as described in EN 197-1 standard. Among these, cements
CEM I do not include additives. It is nevertheless possible to add to these cements slags, fly
ashes, lime fillers or charges, silica fillers or charges. The concrete compositions may be
concretes with different classes of resistances, such as C20/25 to C100/115.
22
The hydraulic composition may more particularly be an aqueous formulation comprising, in
addition to said copolymer(s) according to the invention, water and at least one hydraulic
binder. It may, in addition, optionally comprise one or more extra additive(s).
The hydraulic binder may comprises at least one cement, for example a Portland cement. As
examples, mention may also be made of aluminous cement and calcium sulfoaluminate
cement hydraulic binders.
The hydraulic composition according to the invention may, for example, comprise from 8%
to 75%, for example from 10% to 50% or from 10% to 40% by weight of hydraulic binder
relative to the total weight of the hydraulic composition.
Said copolymer(s) according to the invention may be added to the other constituents of the
hydraulic composition when it is manufactured.
Said copolymer(s) may be used according to the invention at 0.05% to 3% by weight, in
particular from 0.25% to 2.5% by weight relative to the total weight of the hydraulic
composition.
According to a specific embodiment, the hydraulic composition according to the invention
accordingly comprises, relative to the total weight of the composition:
- from 2% to 15% by weight of water,
- from 10% to 30% by weight of hydraulic binder comprising a cement and
- from 0.05% to 3% by weight of one or more copolymer(s) according to the
invention.
According to the embodiment, the hydraulic composition according to the invention may also
comprise, in addition, from 10% to 60% by weight of sand.
According to a specific embodiment, the hydraulic composition according to the invention
may comprise, relative to the total weight of the composition:
- from 2% to 15% by weight of water,
- from 10% to 30% by weight of hydraulic binder comprising a cement,
23
- from 0.05% to 3% by weight of one or more copolymer(s) according to the
invention,
- from 10% to 60% by weight of sand and
- from 10% to 60% by weight of one or more gravel(s).
Of course, the invention is in no way limited to these specific embodiments.
A hydraulic composition according to the invention may comprise different ingredients,
classically used in the field of hydraulic compositions, in particular chosen from sand,
gravels, granulates, fine or ultra-fine fillers or charges, for example calcium carbonate or
silica, anti-foaming agents, thickeners, stabilizers, biocide or anti-bacterial agents and setting
accelerators or retarders.
The present invention also relates to the use of one or more copolymer(s) as described
previously for the preparation of a hydraulic composition advantageously presenting high
early mechanical strength, notably at 1 day.
The invention will now be described by the means of the following example, given as a nonlimiting
illustration of the invention.
EXAMPLE
1. Preparation of the hydraulic compositions
1.1. Preparation of the copolymers
Measurement of the molecular mass of the copolymers
The molecular mass of the copolymers is determined by Steric Exclusion Chromatography
(SEC).
Such a technique uses a WATERSTM brand liquid chromatography device with two detectors.
One of these detectors combines the dynamic static diffusion of light at an angle of 90° with
the viscosimetry measured by a VISCOTEKTM MALVERNTM viscosimetry detector. The
other of these detectors is a WATERSTM brand refractometric concentration detector.
24
The liquid chromatography device has steric exclusion columns chosen suitably by the person
skilled in the art to separate the different molecular weights of the polymers studied. The
elution liquid phase is an aqueous phase containing 1% KNO3.
In a detailed manner, according to a first step, the polymerization solution is diluted to 0.9%
dry in the SEC eluent, which is a 1% KNO3 solution. Then filtration on 0.2 μm. 100 μL are
then injected into the chromatography device (eluent: a 1% KNO3 solution).
The liquid chromatography device contains an isocratic pump (WATERSTM 515) whose flow
rate is set to 0.8 mL/min. The chromatography device also comprises an oven that itself
comprises in series the following system of columns: a GUARD COLUMN
ULTRAHYDROGEL WATERSTM precolumn 6 cm long and 40 mm interior diameter, a
linear ULTRAHYDROGEL WATERSTM column 30 cm long and 7.8 mm interior diameter
and two ULTRAHYDROGEL 120 ANGSTROM WATERSTM columns 30 cm long and
7.8 mm interior diameter.
The detection system is composed first of a RI WATERSTM 410 refractometry detector and
on the other side a 270 DUAL DETECTOR MALVERNTM double viscosimeter detector and
light distribution at an angle of 90°. The oven is taken to the temperature of 55°C and the
refractometer is taken to the temperature of 45°C.
The chromatography device is calibrated by a single PEO 19k PolyCALTM MALVERNTM
calibration standard.
• Copolymer A (not in accordance with the invention)
Copolymer A is obtained by polymerization from a mixture of monomers formed of:
- 85.9 mol.% of acrylic acid and
- 14.1 mol.% of methallyl polyethylene glycol (Mw = 2,400 g/mol).
Synthesis protocol for copolymer A:
The chemical products used are:
- 0.11 g iron sulfate (FeSO4.7H2O),
- 2.0 g of DMDO (1,8-dimercapto-3,6-dioxaoctane, CAS No.: 14970-87-7),
25
- 297 g of methallyl polyethylene glycol at 60% (Mw = 2,400 g/mol),
- 32.5 g of acrylic acid,
- 5.6 g of 35% hydrogen peroxide and
- 5.6 g of 40% sodium bisulfite.
To the reactor containing 50 g of water, the iron sulfate, 20% of the DMDO and 90% of the
60% methallyl polyethylene glycol are introduced. The reactor is heated to 55-60°C. In
parallel, in the reactor, acrylic acid, a solution containing the rest of the DMDO and the 60%
methallyl polyethylene glycol, the hydrogen peroxide and a solution of sodium bisulfite are
injected for 1 h 40 min. The injection hoses are rinsed with 120 g of water and the reactor is
maintained at a temperature of 58-62°C for 1 h 30 min.
The product is cooled then neutralized by adding 34.1 g of 50% NaOH.
The copolymer A obtained has a molecular mass, measured as described previously, of
128,200 g/mol.
• Copolymer B (in accordance with the invention)
Copolymer B is obtained by polymerization from a mixture of monomers formed of:
- 83.4 mol.% of acrylic acid and
- 16.6 mol.% of monomers (b) of formula (I’) in which R1 represents CH3 and having
a polyalkoxylated chain of average molar mass of 1,990 g/mol, formed at 75 mol.% of
ethoxylated units and 25 mol.% of propoxylated units, where the ethoxylated and
propoxylated units are distributed in blocks.
Synthesis protocol for copolymer B:
The chemical products used are:
- 0.11 g of iron sulfate (FeSO4.7H2O),
- 2.3 g of DMDO,
- 297.3 g of monomers (b),
- 32.5 g of acrylic acid,
- 5.6 g of 35% hydrogen peroxide and
- 5.6 g of 40% sodium bisulfite.
26
To the reactor containing 50 g of water, the iron sulfate, 15% of the DMDO and 89% of the
60% methallyl polyoxyalkylene glycol are introduced. The reactor is heated to
55-60°C. In parallel, in the reactor, acrylic acid a solution containing the rest of the DMDO
and the 60% methallyl polyoxyalkylene glycol, the hydrogen peroxide and a solution of
sodium bisulfite are injected for 1 h 40 min. The injection hoses are rinsed with 120 g of
water and the reactor is maintained at a temperature of 58-62°C for
1 h 30 min.
The product is cooled then neutralized by adding 35.8 g of 50% NaOH.
The copolymer B obtained has a molecular mass, measured as described previously, of
86,100 g/mol.
• Copolymer C (in accordance with the invention)
Copolymer C is obtained by polymerization from a mixture of monomers formed of:
- 87.2 mol.% of acrylic and
- 12.8 mol.% of monomers (b) of formula (I’) in which R1 represents CH3 and having
a polyalkoxylated chain with average molar mass of
2,700 g/mol, formed at 88 mol.% of ethoxylated units and 12 mol.% of propoxylated
units, where the ethoxylated and propoxylated units are distributed into blocks.
Synthesis protocol for copolymer C:
Copolymer C is prepared according to a similar procedure to that described previously for
copolymer B.
The copolymer C obtained has a molecular mass, measured as described previously, of
147,200 g/mol.
1.2. Preparation of the hydraulic compositions
In each of the tests, a concrete (660 kg/m3) is prepared according to EN 480-1 standard by
mixing with stirring standardized sand (0/4), cement (CEM I 52.5N Holcim), gravel 4/11,
water and an anti-foaming agent.
No admixture is added to the composition 1 (control).
27
Concrete formulations 2 to 4 are supplemented respectively by the copolymer solutions A, B
and C prepared as described previously.
For the preparation of concrete formulations 2 to 4 incorporating respectively copolymers A,
B and C, the amount of water added is set so that the three hydraulic admixed compositions
have the same water reduction (30%) as the control concrete.
The proportions of each of the constituants of the hydraulic compositions prepared in this
way are indicated in Table 1 hereinbelow.
2. Evaluation of the hydraulic compositions
The compositions are evaluated for their properties of initial fluidity (workability at T0), air
capture, water reduction and compressive strength at 1 day, according to the following
protocols.
Measurement of the workability at T0
The measurement of the initial fluidity (or workability at T0) is carried out, at ambient
temperature, using a bottomless truncated cone made of galvanized steel called an Abrams
cone, according to EN 12350-2 standard. This cone has the following characteristics:
Upper diameter: 100 ± 2 mm,
Lower diameter: 200 ± 2 mm and
Height: 300 ± 2 mm.
The cone is placed on a moistened plate using a sponge.
The cone is filled with a determined amount of each of the preparations. The filling lasts
2 minutes. The contents of the cone is tapped using a metal rod.
As soon as filling is over, the cone is raised vertically, which leads to its contents slumping
onto the plate.
The diameter of the resulting cake is measured after 30 seconds.
Concretes may be classified as a function of their workability according to EN 206-1
standard. In particular, it can be considered that concretes having a difference less than or
equal to 60 mm with spreading have equivalent consistencies.
28
Measurement of air capture
Air capture is measured according to EN 12350-7 standard, paragraph 3.3.
Water reduction measurement
This is measured according to the ADMIXTURE NF EN 934-2 standard.
Measurement of compressive strength
The compressive strength measurements at 1 day are carried out according to
EN 12390-3 standard, paragraph 3. The compressive strength is expressed in MPa.
The tests were carried out on a Class 1 test machine according to the EN 12390-4 standard.
The results obtained for the different hydraulic compositions are indicated in Table 1 below.
Test
Composition 1
(Negative
control)
Composition 2
(Non-compliant)
Composition 3
(Compliant)
Composition 4
(Compliant)
Sand (kg) 24.4 24.4 24.4 24.4
Gravel 4/11 (kg) 35.6 35.6 35.6 35.6
Cement (kg) 25 25 25 25
Water (g) 12,411 8,687 8,687 8,687
Water/cement ratio by
weight 0.50 0.34 0.34 0.34
Water reduction 0% 30% 30% 30%
Admixture (g) -
Copolymer A
(189)
Copolymer B
(187)
Copolymer C
(189)
Dry solids content of
the admixture - 39.7% 40.1% 39.7%
% dry
admixture/cement
admixture
- 0.3 0.3 0.3
Anti-foaming agent
(%/admixture) - 0.5 0.5 0.5
Workability T0 (mm) 580 580 520 560
Air capture at T0 1.0% 3.2% 2.9% 2.9%
Sample weight 4.82 4.92 4.92 4.96
Compressive strength
at 1 day (MPa) 16.0 24.4 25.5 30.3
% of the control
strength value
100% ~ 153% ~ 159% ~ 189%
Table 1
29
All of the hydraulic compositions present an homogeneous appearance, without segregation
of constituents.
Using copolymers B and C according to the invention produces high compressive resistances
at 1 day, while maintaining a satisfactory initial consistency (workability T0).
It is demonstrated in particular that copolymers B and C according to the invention produce,
for the same water reduction for the hydraulic composition, improved resistances at 1 day
(respectively of about 5% and 24%), in comparison with use of copolymer A not in
accordance with the invention, while conserving good workability of the hydraulic
composition.
30
WE CLAIM :
1. A use for increasing the early mechanical strength of a hydraulic composition of at
least one copolymer obtained by polymerization from a mixture of monomers
comprising:
- at least one anionic monomer (a) comprising a polymerisable unsaturated group and a
carboxylic group and
- at least one monomer (b) of the following formula (I):
H2C = C (– R1) – (CH2)p – O – [ (EO)n – (PO)m ] – H (I)
in which:
R1 represents a hydrogen atom or a CH3 group,
p is equal to 1 or 2,
[ (EO)n – (PO)m ] represents a polyalkoxylated chain constituted of ethoxylated units
EO and propoxylated units PO, distributed in blocks, alternating or random and
m and n represent integers varying between 1 and 250, the sum of m and n being
greater than or equal to 10, provided that the molar proportion of the ethoxylated units
in the polyalkoxylated chain (n)/(m+n) is strictly lower than 90%.
2. The use according to claim 1, to obtain a compressive strength of the hydraulic
composition at 1 day, measured according to EN 12390-3 standard, that is greater than
or equal to 155%, in particular greater than or equal to 160%, notably greater than or
equal to 170% and more particularly greater than or equal to 180% of the value of the
strength of the hydraulic composition devoid of said copolymer(s).
3. The use according to any one of the preceding claims, said copolymer(s) being used in
a proportion from 0.05% to 3% by weight, in particular from 0.25% to 2.5% by
weight, based on the total weight of the hydraulic composition.
4. The use according to any one of the preceding claims, characterized in that said
monomer(s) (b) are of the following formula (I’):
H2C = C (– R1) – CH2 – O – [ (EO)n – (PO)m ] – H (I’)
in which R1, n and m are as defined in claim 1.
31
5. The use according to any one of the preceding claims, characterized in that said
copolymer is obtained from at least one monomer (b) of the following formula (II):
H2C = C (– CH3) – CH2 – O – [ (EO)n – (PO)m ] – H (II)
in which n and m are as defined in claim 1.
6. The use according to any one of the preceding claims, characterized in that said
copolymer is obtained from at least one monomer (b) of the following formula (III):
(III)
m and n being as defined in claim 1.
7. The use according to any one of the preceding claims, characterized in that the molar
proportion of the ethoxylated units EO in the polyalkoxylated chain of said
monomer(s) (b) is greater than or equal to 70%, in particular between 70% and 88%,
preferably greater than or equal to 75%.
8. The use according to any one of the preceding claims, characterized in that the total
number of ethoxylated and propoxylated units (m+n) of the polyalkoxylated chain of
the monomer (b) is between 10 and 150, in particular between 18 and 110 and more
particularly between 20 and 70.
9. The use according to any one of the preceding claims, characterized in that said
monomer(s) (b) represent from 1 mol.% to 50 mol.%, in particular from 5 mol.% to
40 mol.%, notably from 5 mol.% to 30 mol.% and more particularly from 10 mol.% to
20 mol.% of the total mole number of monomers that constitute said copolymer.
10. The use according to any one of the preceding claims, characterized in that said
anionic monomer(s) (a) are chosen in the group consisting of acrylic acid, methacrylic
acid, maleic acid, itaconic acid, crotonic acid and mixtures of these monomers, in
particular they are chosen from among acrylic acid, methacrylic acid and their
mixtures.
32
11. The use according to any one of the preceding claims, characterized in that said
copolymer is obtained by polymerization from a mixture of monomers comprising, in
addition to said anionic monomer(s) (a) and said monomer(s) (b) of formula (I), one
or several monomer(s) (c) chosen from among:
- 2-acrylamido-2-methylpropane sulfonic acid (AMPS),
- vinylsufonates, in particular sodium styrene sulfonate,
- amines,
- the esters having a hydroxyl group, for example methacrylate hydroxyethyl (HEMA),
acrylate hydroxyethyl, methacrylate hydroxypropyl and acrylate hydroxypropyl,
- alkylene glycol methacrylate or acrylate phosphates, in particular ethylene glycol
methacrylate phosphate or again ethylene glycol acrylate phosphate,
- acrylamide or methacrylamide,
- phosphonic monomers such as vinylphosphonates and alkyl phosphonates,
- the macromonomers of the following formula (VI):
Ra – [(EO)q – (PO)r – (BO)s] – Ra’ (VI)
in which:
[(EO)q – (PO)r – (BO)s] represents a polyalkoxylated chain constituted of alkoxylated
units, distributed in blocks, alternating or random, chosen from among the ethoxylated
units EO, the propoxylated units PO and the butoxylated units BO,
q, r and s represent, independently of one another, 0 or an integer varying between 1
and 250, the sum of m, n and p being between 10 and 250,
Ra represents a radical chosen in the group consisting of acrylic esters, methacrylic
esters and a mixture of these esters and
Ra’ represents hydrogen or an alkyl group with from 1 to 4 carbon atoms,
- the hydrophobic monomers of the following formula (VII):
Rb – [(EO)t – (PO)u – (BO)v] – Rb’ (VII)
in which:
[(EO)t – (PO)u – (BO)v] represents a polyalkoxylated chain constituted of alkoxylated
units, distributed in blocks, alternating or random, chosen from among the ethoxylated
units EO, the propoxylated units PO and the butoxylated units BO,
t, u and v represent, independently of one another, 0 or an integer varying between 1
and 250, the sum of m, n and p being between 10 and 250,
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Rb represents a radical chosen in the group consisting of acrylic esters, methacrylic
esters and a mixture of these esters and
Rb’ represents an alkyl group with from 8 to 40 carbon atoms and
- the cross-linking monomers.