WO2016146935A1

WO2016146935A1 - Use of copolymers for improving the early-age mechanical resistance of a hydraulic composition

Info

Publication number: WO2016146935A1
Application number: PCT/FR2016/050571
Authority: WO
Inventors: David Platel; Benoît MAGNY; Jean-Marc Suau; Clémentine CHAMPAGNE
Original assignee: Coatex
Priority date: 2015-03-16
Filing date: 2016-03-15
Publication date: 2016-09-22
Also published as: FR3033787B1; EP3271305A1; CN107406321A; MX2017011139A; FR3033787A1

Abstract

The invention concerns the use, for increasing the early-age mechanical resistance of a hydraulic composition, of at least one copolymer obtained by polymerisation from a mixture of monomers comprising: - at least one anionic monomer (a) comprising a polymerisable unsaturated function and a carboxylic group; and - at least one monomer (b) of following formula (I): H₂C=C(-R₁)-(CH₂)_p-O-[EO)_n-(PO)_m]-H (I) in which: R₁ represents a hydrogen atom or a CH₃group, p is equal to 1 or 2, [(EO)_n-(PO)_m] represents a polyalkoxylated chain consisting of ethoxylated units EO and propoxylated units PO, distributed into blocks, alternating or statistical, 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 less than 90 %.

Description

USE OF COPOLYMERS FOR IMPROVING MECHANICAL RESISTANCE TO YOUNG PEOPLE OF A HYDRAULIC COMPOSITION

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 mechanical strength properties at young ages of hydraulic compositions.

Such hydraulic compositions are intended for all construction markets.

The hydraulic compositions generally comprise various chemical additives for modulating their properties. Among these, the so-called "water-reducing agents", also known as "dispersing agents", "fluidizing agents", "plasticizing agents" or "superplasticizers", are well known and have been used for many years. These dispersants lead to a decrease in the water content of the hydraulic compositions, which makes it possible to improve the performance of these compositions and in particular their mechanical strength.

For example, comb-type carboxylic polymers have been developed as dispersants. In general, these polymers have a skeleton generally of (meth) acrylic nature and side chains terminated by hydrophilic groups, for example polyoxyalkylated side groups.

CN 1148329 C thus proposes, as dispersing agents for cements, copolymers obtained by polymerization from a monomer of the monocarboxylic acid type, such as (meth) acrylic acid and a monomer of the type polyalkylene glycol ether in which the proportion in ethoxylated units is at least 90 mol% of all the alkoxylated units, preferably a polyethylene glycol ether.

JP 2006/282414 relates to a high strength cement developer. It contains, as essential components, (a) glycerol or a glycerol derivative and (b) a polycarboxylic acid-based copolymer having a polyoxyalkylene-type compound on a side chain.

US 6,211,317 discloses emulsion copolymers of unsaturated carboxylic acid derivatives, oxyalkylene alkenyl glycol ethers, unsaturated dicarboximides or amides and vinyl monomers. They are described for use as additives for hydraulic binders, especially cement. On the other hand, the workability of the compositions, for example concrete compositions, increases with their water content. However, it is essential to have good maneuverability or initial fluidity of the hydraulic composition, for example concrete, insofar as this property conditions its implementation, for example for filling a formwork. The maneuverability can be evaluated by measuring the slump (or "slump" in English) according to EN 12350-2.

Therefore, it is generally sought, in the formulation of a hydraulic composition, to achieve a compromise between the mechanical properties and the workability of the hydraulic composition.

Better mechanical strength is one of the properties particularly sought after in the evaluation of hydraulic compositions. The measurement of the mechanical strength of the hydraulic compositions can be carried out at different times, for example at 1 day, 7 days or 28 days, the time TO corresponding to the preparation of the hydraulic composition. In the context of the present invention, particular attention is given to the mechanical strength at young ages. High mechanical strength at young ages is particularly desirable in the case of concreting to be carried out in cold weather or for quick stripping on site.

This property of "early age strength", also known as "1 day compressive strength", is defined as the evolution of the compressive strength as a function of the age of preparation of the hydraulic composition, in the zone TO at T = 1 day following the preparation of the hydraulic composition.

The present invention aims precisely to improve the resistance to young ages, including 1 day, hydraulic compositions without altering their fluidity or initial handling.

It thus relates, according to a first of its aspects, the use to increase the mechanical strength at young ages, particularly at 1 day, of a hydraulic composition of at least one copolymer obtained by polymerization from a monomer mixture comprising:

at least one anionic monomer (a) comprising a polymerizable unsaturated functional group and a carboxylic group and

at least one monomer (b) of formula (I) below:

H ₂ C = C (- R 1) - (CH ₂ ) _P - O - [(EO) - (PO) _m ] - H (I) in which:

Ri represents a hydrogen atom or a C¾ group, p is 1 or 2,

[(EO) n - (PO) m] represents a polyalkoxylated chain consisting of ethoxylated units EO and propoxylated units PO, divided into blocks, alternating or statistical 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 at 90%.

The copolymers used according to the invention, as defined above, comprising at least units derived from the anionic monomers (a) and units derived from the monomers (b) of formula (I), are more simply designated in the following the text under the name "copolymers according to the invention".

In the context of the present invention, the "early age" mechanical resistance refers more particularly to the compressive strength at 24 hours (± 15 minutes) after the preparation of the hydraulic composition. Compressive strength at 1 day can be measured according to EN 12390-3.

By "improving" or "increasing" the mechanical strength at young ages, it is more particularly meant, in the context of the invention, to access by the implementation of the copolymer according to the invention as an adjuvant in a hydraulic composition. an increase in compressive strength to 1 day (measured according to EN 12390-3) of at least 4%, in particular by at least 4.5%, in particular by at least 10%, of preferably at least 15% and more preferably at least 20%, in comparison with the resistance value obtained with the use as adjuvant in the same hydraulic composition of a copolymer, not according to the invention, of similar composition except that the polyalkoxylated chain of monomeric units of type (b) is a polyethylene glycol chain (100 mol% in ethoxylated units EO).

The use of copolymers according to the invention allows the faster development of the mechanical strength at young ages of the hydraulic compositions that incorporate them. In other words, such copolymers make it possible to improve the short-term mechanical strength ("at young ages"), especially at 1 day, of the hydraulic compositions in which they are used. As illustrated in the examples which follow, the copolymers according to the invention advantageously make it possible to obtain strengths at young ages, particularly at 1 day, elevated.

More particularly, the use of a copolymer according to the invention in a hydraulic composition, for example a concrete composition, makes it possible to obtain a compressive strength at 1 day (measured according to the EN 12390-3 standard). the adjuvanted hydraulic composition according to the invention greater than or equal to 155% of the value of the resistance 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, in particular greater than or equal to 170, or even greater than or equal to 180% of the value of the resistance of the hydraulic composition without copolymer according to the invention .

The implementation of the copolymers according to the invention proves, for example, particularly advantageous for concreting. The increase in the short-term mechanical strengths of the hydraulic composition, for example concrete, also allows faster demolding and stripping.

Furthermore, advantageously, this increase in mechanical strength at young ages is not at the expense of other performance of the hydraulic composition, including its fluidity or initial handling.

Other characteristics, advantages and modes of application of the implementation of the copolymers according to the invention will emerge more clearly on reading the description and the example which will follow, given by way of illustration and not limitation.

In the remainder of the text, the expressions "between ... and ...", "ranging from ... to ..." and "varying from ... to ..." are equivalent and mean to mean that terminals are included unless otherwise stated.

Unless otherwise indicated, the expression "comprising / including a" shall be understood as "comprising / including at least one".

Copolymers according to the invention

As indicated above, the present invention uses copolymers obtained by polymerization from at least:

one or more anionic monomer (s) comprising a polymerizable unsaturated functional group and a carboxylic group, noted as "monomer (s) (a)" in the remainder of the text and one or more monomers of the following formula (I), denoted "monomers (b)" in the rest of the text,

H ₂ C = C (- R 1) - (CH ₂ ) _P - O - [(EO) - (PO) _m ] - H (I) in which:

Ri represents a hydrogen atom or a C¾ group,

p is 1 or 2,

The copolymers used according to the invention may optionally comprise other polymerizable monomers. The optional monomers optionally used in the composition of a copolymer according to the invention may be of various natures, as detailed 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 mol of monomers. constituents of the copolymer.

According to an alternative embodiment, the copolymer used according to the invention consists solely of units deriving from the monomers (a) and (b). In other words, the copolymer can be obtained by polymerization from a monomer mixture formed of one or more anionic monomer (s) (a) and one or more monomer (s) (b) of the formula (I). The distribution of the units deriving from the monomers (a) and those deriving from the monomers (b) in the copolymer according to the invention can be of block, alternating or statistical type. According to one embodiment, it is a statistical or alternating distribution. According to another embodiment, it is a block-type distribution.

The copolymer used according to the invention can be obtained by polymerization from a monomer mixture consisting of:

at least one monomer (b) of formula (I): H ₂ C = C (- R 1) - (CH ₂ ) _P - O - [(EO) - (PO) _m ] - H (I)

in which :

Ri represents a hydrogen atom or a C¾ group,

p is 1 or 2,

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 10; equal to

70% and strictly less than 90%.

The amounts of monomers (a) and (b) used then correspond to 100% by weight of the total amounts of monomers forming the copolymer used according to the invention.

Anionic monomer (a) having a polimerizable unsaturated functional group and a carboxylic group.

The anionic monomers (a) used 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 mixtures of these monomers.

The monomer or monomers (a) may be in acid form, for example carboxylic acid and / or salt form, for example carboxylate.

It is understood that a single or a mixture of several different monomers (a) can enter into the composition of the copolymer according to the invention. For example, it may be a mixture of acrylic acid monomers and methacrylic acid monomers or a mixture of monomers of maleic acid, acrylic acid and methacrylic acid.

According to a particular embodiment, the copolymer used according to the invention is formed from at least acrylic acid and / or methacrylic acid, in particular at least acrylic acid (AA).

According to an alternative embodiment, the at least one anionic monomer (s) (a) used in the composition of the copolymer used according to the invention are chosen from acrylic acid, methacrylic acid and their mixture. According to one particular embodiment, the anionic monomer (s) (s) (a) may represent from 50% to 99% by mole, in particular from 60% to 95% by mole, in particular from 70% to 95% by mole, and more particularly from 80% to 90% molar of the total number of moles of constituent monomers of the copolymer according to the invention.

Monomer (b) of formula (I)

As indicated above, the monomers (b) used in the composition of the copolymer used according to the invention correspond to the following formula (I):

H ₂ C = C (- R 1) - (CH ₂ ) _P - O - [(EO) - (PO) _m ] - H (I) in which:

R 1 represents a hydrogen atom or a CH ₃ group,

p is 1 or 2,

[(EO) n - (PO) m] represents a polyalkoxylated chain consisting of ethoxylated units EO and propoxylated units PO and

By "polyalkoxylated" chain is meant a chain of poly (alkylene glycol) type. By "poly (alkylene glycol)" is meant a polymer of an alkylene glycol derived from an olefinic oxide.

The poly (alkylene glycol) chain of the monomer (b) is formed of ethoxylated units (or "ethylene-oxy"), denoted "EO", of formula -CH ₂ -CH ₂ -O- and propoxylated units (or "Propyleneoxy"), denoted "PO", of formula -CH ₂ -CH (CH ₃ ) -O-.

The schematic representation "[(EO) _n - (PO) _m ]" does not presuppose the order of the ethoxylated and propoxylated units of the polyalkoxylated chain. In fact, the polyalkoxylated chain may have a distribution of units EO and PO block type, statistical or alternating.

According to a particular embodiment, the units EO and PO are divided into blocks. In particular, the polyalkoxylated chain of the monomer (b) may be of diblock type and be formed of a polyoxyethylene block and a polyoxypropylene block.

According to an alternative embodiment, p in formula (I) above is 1. In other words, according to this variant embodiment, the monomer (s) (b) used in the composition of the copolymer according to the invention have the following formula (Γ):

H ₂ C = C (-Ri) -CH ₂ -O- [(EO) "- (PO) _m ] -H (Γ) in which R 1, n and m are as defined above.

According to a particular embodiment, the copolymer used according to the invention is formed from at least one monomer (b) of formula (I) or (Γ) above, in which R 1 represents a methyl group.

In particular, according to a particular embodiment, the copolymer used according to the invention is obtained from at least one monomer (b) of formula (II) below:

H ₂ C = C (-CH ₃ ) -CH ₂ -O- [(EO) "- (PO) _m ] -H (II) wherein n and m are as defined above.

As indicated above, the schematic representation "[(EO) _n - (PO) _m ]" does not presuppose the order of the ethoxylated and propoxylated units of the polyalkoxylated chain. The polyalkoxylated chain may have a distribution of units EO and PO block type, statistical or alternating, in particular blocks.

According to a particular embodiment, the copolymer used according to the invention is obtained from at least one monomer (b) of formula (III) below:

m and n being as defined above.

In the aforementioned formula (III), the polyalkoxylated chain is formed of a first polyoxyethylene block and a second polyoxypropylene block.

According to another embodiment variant, p in formula (I) above is 2.

In other words, according to this variant embodiment, the monomer (s) (b) used in the composition of the copolymer according to the invention have the following formula (I "):

H ₂ C = C (-Ri) -CH ₂ -CH ₂ -O- [(EO) "- (PO) _m ] -H (I") in which R 1, n and m are as defined above. According to a particular embodiment, the copolymer used according to the invention is formed from at least one monomer (b) of formula (I ") above, in which R 1 represents a methyl group.

In particular, according to a particular embodiment, the copolymer used according to the invention is formed from at least one monomer (b) of formula (IV) below:

H ₂ C = C (-CH ₃ ) -CH ₂ -CH ₂ -O- [(EO) _n - (PO) _m ] -H (IV) in which n and m are as defined above.

According to a particular embodiment, the copolymer used according to the invention is obtained from at least one monomer (b) of formula (V) below:

H ₂ C = C (-CH ₃ ) -CH ₂ -CH ₂ -O- (EO) _n - (PO) _m - H (V) m and n being as defined above.

In the aforementioned formula (V), the polyalkoxylated chain is formed of a first polyoxyethylene block and a second polyoxypropylene block.

As for the anionic monomers (a), it is understood that a single or a mixture of several different monomers (b) can enter into the composition of the copolymer used according to the invention.

Thus, according to a particular embodiment, the copolymer according to the invention is obtained from at least one mixture of at least one monomer (bi) of formula (I) in which R 1 represents a hydrogen atom and a at least one monomer (b ₂ ) of formula (I) in which R 1 represents a methyl group.

In particular, the copolymer according to the invention can be obtained from at least one mixture of at least one monomer (bi ') of formula (Γ) above, in which R 1 represents a hydrogen atom and from minus one monomer (b ₂ ') of formula (Γ) above, in which R 1 represents a methyl group (in other words, a monomer (b ₂ ') of formula (II) above).

In the context of this particular embodiment, the monomer (s) (bi ') and the monomer (s) (b ₂ ') used in the composition of the copolymer according to the invention can be used in a molar monomer (s) (bi ') / monomer (s) (b ₂ ') ratio ranging from 10 to 0.01, in particular from 1 to 0.1. According to yet another particular embodiment, the copolymer according to the invention can be obtained from at least one mixture of at least one monomer (bi ') of formula (Γ) mentioned above and at least one monomer ( b ₂ ") of formula (I") above. In particular, the copolymer according to the invention can be obtained from at least one mixture of at least one monomer (bi ') of formula (Γ) above in which R 1 represents a methyl group (in other words, a monomer ( bi ') of formula (II) above) and at least one monomer (b ₂ ") of formula (I") above wherein R 1 represents a methyl group (in other words, a monomer (b ₂ ") of formula ( IV) above).

According to an essential characteristic of the monomer (s) (b) used in the composition of the copolymer according to the invention, the molar proportion of ethoxylated units EO in the polyalkoxylated chain (that is to say (n) / (m) + n) in formula (I), (Γ), (II) or (III) above) is strictly less than 90%.

According to a particular 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 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 particular embodiment, the molar proportion of ethoxylated units EO in the polyalkoxylated chain may be less than or equal to 85, in particular less than or equal to 80%.

According to another particular 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 can be for example about 88%.

The molar ratio between the ethoxylated units and the propoxylated units of the polyalkoxylated chain may more particularly be between 2.5 and 8, in particular between 2.8 and 7.5, in particular between 6 and 7.5.

As indicated above, the total number of ethoxylated and propoxylated units of the polyalkoxylated chain (that is, the sum of m and n) of the monomer (b) is greater than or equal to 10.

According to a particular embodiment, it may be between 10 and 150, in particular between 18 and 110 and more particularly between 20 and 70.

The polyalkoxylated chain of the monomer (b) according to the invention can thus have a number-average molar mass of between 450 g / mol and 7,500 g / mol, in especially between 900 g / mol and 500 g / mol and more particularly between 1000 g / mol and 3500 g / mol.

It is understood that the various variants and particular embodiments given above can be combined, as far as possible, to define other particular variants or embodiments.

The monomers (b) can be prepared by techniques known to those skilled in the art, by growing the desired polyalkoxylated chain by polymerization from ethylene oxide and propylene oxide monomers to an allyl or methallyl alcohol .

According to a particular embodiment, the monomer (s) (b) may represent from 1% to 50% by mole, in particular from 5% to 40% by mole, in particular from 5% to 30% by mole and more particularly from 10% to 30% by mole. at 20 mol% of the total number of moles of constituent monomers of the copolymer used according to the invention.

The monomer (s) (b) may be in various forms, in particular in solid form, in particular in the form of powder or flakes, or in liquid form (liquid formed by monomers (b) or aqueous monomer solution ( b)).

In particular, the monomers (b) are water-soluble.

Preferably, the monomer (s) (b) are used in liquid form, in particular in aqueous solution, this form being particularly suitable for the synthesis of the copolymer used according to the invention.

The molar ratio between the anionic monomer (s) (s) (a) and the monomer (s) (b) used in the composition of the copolymer according to the invention may be more particularly between 1 and 99, in particularly between 2.3 and 19 and more particularly between 4 and 9.

Optional monomers

As indicated above, the copolymer used according to the invention can be obtained by polymerization from a monomer mixture comprising, besides said monomer (s) (a) and said monomer (s) (b). , one or more additional monomer (s), different from the monomers (a) and (b) noted (s) "monomer (s) (c)" in the following text.

The additional monomers (c) may be more particularly chosen from:

2-acrylamino-2-methylpropanesulphonic acid (AMPS),

vinylsulphonates, in particular sodium styrene sulphonate, - the 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 ethylene glycol acrylate phosphate,

acrylamide or methacrylamide,

phosphonic monomers, such as vinylphosphonates and alkyl phosphonates,

the macromonomers of formula (VI) below:

Ra - [(EO) _q - (PO) r - (BO) s] - Ra '(VI)

in which :

[(EO) _q - (PO) r - (BO) _s ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from ethoxylated units EO, propoxylated units PO and butoxylated units B , q, r and s represent, independently of each other, 0 or an integer ranging between 1 and 250, the sum of m, n and p being between 10 and 250,

R _a represents a radical selected from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters and

R _a 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

the hydrophobic monomers of formula (VII) below:

R _b - [(EO) _t - (PO) u - (BO),] - R _b '(VII)

in which :

[(EO) t - (PO) u - (BO) v] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from the ethoxylated units EO, the propoxylated units PO and the butoxylated units B , t, u and v represent, independently of one another, 0 or an integer ranging between 1 and 250, the sum of m, n and p being between 10 and 250,

Rb represents a radical selected from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters and

Rb 'represents an alkyl group having from 8 to 40 carbon atoms and

crosslinking monomers. According to a particular embodiment, in formula (VI) above, s is equal to 0 and q and r represent an integer ranging between 1 and 250, for example between 10 and 150 or between 10 and 100.

According to a particular embodiment, in the aforementioned formula (VII), v is equal to 0 and t and u represent an integer ranging between 1 and 250, for example between 10 and 150 or between 10 and 100.

The additional monomer (s) (s) (c) may also be chosen from crosslinking monomers.

The copolymer according to the invention may, for example, comprise a single crosslinking monomer. According to another embodiment, it comprises two different crosslinking monomers.

The crosslinking monomer may have a hydrophilic, hydrophobic or amphiphilic character. Examples of these compounds include di (meth) acrylate compounds such as polyalkylene glycol di (meth) acrylate, especially polypropylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, di (meth) ) polyethylene glycol acrylate, triethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,6-butylene glycol di (meth) acrylate, di (meth) acrylate 1,6-hexanediol, neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, but also 2,2'-bis (4- (acryloxypropyloxyphenyl) propane, 2,2'-bis (4- (acryloxydiethoxyphenyl) propane and zinc acrylate, tri (meth) acrylate compounds such as trimethylolpropane tri (meth) acrylate, tri (meth) acrylate trimethylolethane, tri (meth) acrylate pentaerythritol and tetramethylolmethane tri (meth) acrylate, tetra (meth) acrylate compounds such as ditrimethylolpropane tetra (meth) acrylate, tetra (meth) ) tetramethylolmethane 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 having 2 to 8 groups per molecule, polyallyl ethers pentaerythritol such as pentaerythritol diallyl ether, pentaerythritol triallyl ether and pentaerythritol tetraallyl ether, polyallyl ethers of trimethylolpropane such as diallyl trimethylolpropane ether and triallyl trimethylolpropane ether. Other polyunsaturated compounds include divinyl glycol, divinyl benzene, divinylcyclohexyl and methylenebisacrylamide. In another aspect, the crosslinking 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 a reaction of addition with an isocyanate such as 3-isopropenyl-dimethylbenzene isocyanate.

The following compounds can also be used to obtain crosslinking 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 particular embodiment, the crosslinking monomer is chosen from (meth) acrylates having at least two polymerizable ethylenically unsaturated double bonds (for example prepared by esterification of (meth) acrylic acid with a linear or branched polyol having 2 at 12 carbon atoms and at least two hydroxyl groups), polyalkenyl polyethers having at least two polymerizable ethylenically unsaturated double bonds (for example prepared by etherification of alkenyl halide with a linear or branched polyol having from 2 to 12 carbon atoms and at least two hydroxyl groups) and mixtures of these crosslinking monomers.

According to one embodiment of the present invention, the copolymer comprises two crosslinking monomers:

said first crosslinking monomer being a (meth) acrylate having at least two polymerizable ethylenically unsaturated double bonds (for example prepared by esterification of (meth) acrylic acid with a linear or branched polyol having from 2 to 12 carbon atoms and at least one minus two hydroxyl groups) and

said second crosslinking monomer being a polyalkenyl polyether having at least two polymerizable ethylenically unsaturated double bonds (for example prepared by etherification of alkenyl halide with a linear or branched polyol having from 2 to 12 carbon atoms and at least two hydroxyl groups). According to another embodiment, the copolymer comprises two crosslinking monomers of different natures, for example trimethylolpropane tri (meth) acrylate (TMPTA or TMPTMA) and trimethylolpropane diallyl ether (TMPDAE).

It is understood that the additional monomer content (s) used, for example monomer (s) crosslinking (s), is adjusted not to alter the desired properties of the copolymer.

In general, the additional monomer (s) (s) (c) may represent less than 20 mol%, in particular less than 15 mol%, especially less than 10 mol% and more particularly less than 5 mol%. of the total number of moles of constituent monomers of the copolymer according to the invention.

The various particular modes described for each of the monomers used in the composition of the copolymer used according to the invention can be combined.

According to a particular embodiment, the copolymer used according to the invention can thus be obtained by polymerization from a monomer mixture comprising or even consisting of:

one or more anionic monomer (s) (a) chosen from acrylic acid, methacrylic acid and mixtures thereof, in particular acrylic acid and

- One or more monomer (s) (b) of formula (Γ) above, in particular of formula (II) above, wherein the ethoxylated and propoxylated units are more particularly divided into blocks.

According to a particular embodiment, the copolymer according to the invention comprises at least units derived from acrylic acid and units derived from a monomer of formula (II), in particular of formula (III) as described above.

According to a first particular embodiment, the copolymer used according to the invention is obtained by polymerization of at least:

- 50% to 99% molar of at least one anionic monomer (a), in particular as defined above and

1% to 50% molar of at least one monomer (b) of formula (I), in particular as defined above,

the molar percentages of each monomer being expressed relative to the total number of moles of constituent monomers of the copolymer.

According to a second particular embodiment, the copolymer used according to the invention is obtained by polymerization of at least: - 70% to 95% molar of at least one anionic monomer (a), in particular as defined above and

- 5% to 30% molar of at least one monomer (b) of formula (I), in particular as defined above,

According to a third particular embodiment, the copolymer used according to the invention is obtained by polymerization of at least:

- 80% to 90% molar of at least one anionic monomer (a), in particular as defined above and

- 10% to 20% molar of at least one monomer (b) of formula (I), in particular as defined above,

According to these three particular embodiments, the sum of the molar percentages of the monomers (a) and of the monomers (b) is equal to 100%. In other words, according to these three embodiments of the invention, the copolymer consists solely of units derived from the monomers (a) and (b) in the molar proportions indicated.

The copolymer according to the invention may have a weight average molecular weight Mw of 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 weight or Mw can be determined by

Steric Exclusion Chromatography (CES), as described more specifically in the following example.

The copolymer used according to the invention may be in the form of salts, stoichiometric or otherwise, mixed or not, and consisting of alkali metals, alkaline earth metals, amines or quaternary ammoniums.

According to a particular embodiment, the copolymer according to the invention is in acid form.

According to another embodiment, the copolymer according to the invention is in neutralized form.

According to yet another embodiment, the copolymer according to the invention is in partially or totally neutralized form. According to a particular embodiment, the copolymer is neutralized with an ion selected from the group consisting of potassium ion, sodium ion, lithium ion, calcium ion, magnesium ion, ammonium ion, the diethanolammonium ion and a mixture of these ions. The copolymer according to the invention can be prepared by conventional polymerization techniques from monomers (a), (b) and optionally (c).

According to an alternative embodiment, the copolymer according to the invention can be obtained by radical polymerization, in particular by controlled radical polymerization.

According to another of its aspects, the invention relates to a copolymer as defined above, in particular obtained by polymerization from a monomer mixture 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 in ethoxylated units greater than or equal to 70% and strictly less than 90%.

Use to increase the resistance at young ages of the hydraulic compositions As mentioned above, the copolymers according to the invention are particularly effective in increasing the mechanical strength at young ages of hydraulic compositions.

The invention thus relates to a method for increasing the mechanical strength at young ages, and particularly at 1 day, of a hydraulic composition comprising adding to said hydraulic composition at least one copolymer as described above. The adjuvanted hydraulic composition according to the invention has a faster development of mechanical strength at young ages, especially at 1 day.

Advantageously, the resistance at 1 day (measured according to EN 12390-3) of the hydraulic composition added according to the invention may be greater than or equal to 155% of the value of the strength of the hydraulic composition without copolymer according to the invention. In particular, it may be greater than or equal to 160, in particular 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.

The invention thus relates to the use of at least one copolymer as described above as an adjuvant in a hydraulic composition, for example a concrete composition, to increase the rate of development of mechanical strength at young ages, especially at 1 day.

The adjuvant according to the invention can be used in various forms, in particular in liquid form. It can in particular be in the form of an aqueous solution of one or more copolymer (s) according to the invention, the dry extract of which can be more particularly 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 above 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 (s) as defined previously.

The water-reducing agent according to the invention, in addition to allowing a reduction in the quantity of water of the hydraulic composition in which it is used, advantageously allows a faster development of the mechanical strength at young ages, especially at 1 day.

According to yet another of its aspects, the invention relates to a hydraulic composition comprising at least one copolymer as described above.

The hydraulic compositions can be of various kinds. They can be used for the manufacture of a grout, a coating, an adhesive, a concrete or a mortar. They may include impurities, for example clays. These compositions may in particular comprise latexes, fibers, organic granulates, inorganic granulates, fillers or fillers and / or CaCO ₃ .

Hydraulic compositions, for example concrete and mortar compositions, may comprise as hydraulic binder various types of cements, such as, for example, cements CEM I, CEM II, CEM III, CEM IV and CEM V as described in the standard EN 197-1. Of these, CEM I cements do not have additions. It is nonetheless possible to add to these cements slags, fly ash, fillers or calcareous fillers, fillers or siliceous fillers. The concrete compositions may be concrete of classes of different strengths, such as C20 / 25 to C100 / 115.

The hydraulic composition may more particularly be an aqueous formulation comprising, in addition to the copolymer (s) according to the invention, water and at least one hydraulic binder. It may, in addition, possibly include one or more additive (s) annex (s). The hydraulic binder may comprise at least one cement, for example a Portland cement. Mention may also be made, by way of examples, of hydraulic binders of aluminous cement type and sulpho-alumino-calcium cement.

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 with respect to the total weight of the hydraulic composition.

The at least one copolymer (s) according to the invention may be added to the other constituents of the hydraulic composition during its manufacture.

The at least one copolymer (s) may be used according to the invention in a proportion of from 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 particular embodiment, the hydraulic composition according to the invention thus 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 this embodiment, the hydraulic composition according to the invention can also comprise, in addition, from 10% to 60% by weight of sand.

According to a particular 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,

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 particular embodiments.

A hydraulic composition according to the invention may comprise various ingredients, conventionally used in the field of hydraulic compositions, in particular chosen from sand, gravel, aggregates, fillers or fine or ultra-fine fillers, for example carbonate calcium or silica, defoamers, thickeners, stabilizers, biocides or anti-bacterials, and accelerators or set retarders. The present invention also relates to the use of one or more copolymer (s) such (s) as described above for the preparation of a hydraulic composition advantageously having a mechanical strength at young ages, especially 1 day, high .

The invention will now be described by means of the following example, given by way of illustration and not limitation of the invention.

EXAMPLE 1. Preparation of Hydraulic Compositions

1.1. Preparation of copolymers

Measurement of the molecular mass of copolymers

The molecular weight of the copolymers is determined by Steric Exclusion Chromatography (CES).

Such a technique implements a WATERS ™ brand liquid chromatography apparatus with two detectors. One of these detectors combines the static dynamic scattering of light at a 90 ° angle with viscometry measured by a VISCOTEK ™ MALVERN ™ viscometer. The other detector is a WATERS ™ refractometric concentration detector.

This liquid chromatography apparatus is provided with steric exclusion columns appropriately chosen by those skilled in the art in order to separate the different molecular weights of the polymers studied. The liquid phase of elution is an aqueous phase containing 1% of KN0 ₃ .

In a detailed manner, in a first step, the polymerization solution in the eluent of the CES, which is a 1% solution of KNO3, is diluted to 0.9% dry. Then, it is filtered at 0.2 μιη. 100 μΐ _^ are then injected into the chromatograph (eluent: a 1% solution of KNO3).

The liquid chromatography apparatus contains an isocratic pump (WATERS ™ 515) with a flow rate of 0.8 mL / min. The chromatography apparatus also comprises an oven which itself comprises in series the following column system: a precolumn GUARD COLUMN type ULTRAHYDROGEL WATERS ™ 6 cm long and 40 mm internal diameter, a linear column type ULTRAHYDROGEL WATERS ™ 30 cm long and 7.8 mm inside diameter and two columns ULTRAHYDROGEL 120 ANGSTROM WATERS 30 cm long and 7.8 mm inside diameter.

The detection system, on the other hand, consists of a RI WATERS ™ 410 type refractometric detector and the other side of a dual viscometer detector and light scattering at a 90 ° angle. type 270 DUAL DETECTOR MALVERN ™. The oven is heated to 55 ° C and the refractometer is heated to 45 ° C.

The chromato graphie instrument is calibrated by a single standard of PEO 19k type PolyCAL ™ MALVERN ™.

• Copolymer A (not according to the invention)

The copolymer A is obtained by polymerization from a monomer mixture formed of:

- 85.9 mol% of acrylic acid and

14.1 mol% of methallyl polyethylene glycol (Mw = 2400 g / mol).

Copolymer A synthesis protocol:

The chemicals used are:

0.11 g of iron sulphate (FeSO ₄ .7H ₂ O),

2.0 g of DMDO (1,8-dimercapto-3,6-dioxaoctane, CAS No. 14970-87-7),

297 g of 60% methallyl polyethylene glycol (Mw = 2400 g / mol),

32.5 g of acrylic acid,

- 5.6 g of hydrogen peroxide at 35% and

5.6 g of 40% sodium bisulphite.

In the reactor containing 50 g of water, iron sulphate, 20% of the DMDO and

90% of the methallyl polyethylene glycol at 60%. The reactor is heated to 55-60 ° C. Acrylic acid is injected in parallel into the reactor, a solution containing the remainder of the

DMDO and methalyl polyethylene glycol at 60, hydrogen peroxide and a solution of sodium bisulfite during lh40. The injection pipes are rinsed with 120 g of water and the reactor is maintained at a temperature of 58-62 ° C. for 1h30.

The product is cooled and then neutralized by adding 34.1 g of 50% NaOH.

The copolymer A obtained has a molecular mass, measured as described above, of 128,200 g / mol. Copolymer B (in accordance with the invention)

The copolymer B is obtained by polymerization from a monomer mixture formed of:

- 83.4 mol% of acrylic acid and

16.6 mol% of monomers (b) of formula (Γ) in which R 1 represents C¾ and having a polyalkoxylated chain of average molar mass of 1990 g / mol, formed at 75 mol% of ethoxylated units and 25 mol% of propoxylated units, the ethoxylated and propoxylated units being divided into blocks.

Copolymer B synthesis protocol:

The chemicals used are:

0.1 g of iron sulphate (FeSO ₄ .7H ₂ O),

2.3 g of DMDO,

297.3 g of the monomers (b),

32.5 g of acrylic acid,

- 5.6 g of hydrogen peroxide at 35% and

5.6 g of 40% sodium bisulphite.

In the reactor containing 50 g of water, iron sulphate, 15% DMDO and

89% of the methallyl polyoxyalkylene glycol at 60%. The reactor is heated to 55-60 ° C. Acrylic acid is injected in parallel into the reactor, a solution containing the remainder of the

DMDO and methallyl polyoxyalkylene glycol at 60, hydrogen peroxide and a solution of sodium bisulfite during lh40. The injection pipes are rinsed with 120 g of water and the reactor is maintained at a temperature of 58-62 ° C. for 1h30.

The product is cooled and then neutralized by adding 35.8 g of 50% NaOH.

The copolymer B obtained has a molecular mass, measured as described above, of 86 100 g / mol.

• Copolymer C (according to the invention)

The copolymer C is obtained by polymerization from a mixture formed of:

- 87.2 mol% of acrylic acid and

12.8 mol% of monomers (b) of formula (Γ) in which R 1 represents C¾ and having a polyalkoxylated chain of average molar mass of 2700 g / mol, formed at 88 mol% of ethoxylated units and 12 mol% of propoxylated units, the ethoxylated and propoxylated units being divided into blocks. Synthetic protocol of the copolymer C:

The copolymer C is prepared according to a procedure similar to that described above for the copolymer B.

The copolymer C obtained has a molecular mass, measured as described above, of 147,200 g / mol.

1.2. Preparation of hydraulic compositions

In each test, a concrete (660 kg / m ³ ) according to EN 480-1 is prepared by stirring with standardized sand (0/4), cement (CEM I 52.5N Holcim), gravel 4 / 11, water and an antifoaming agent.

No adjuvant is added to composition 1 (control).

Formulations 2 to 4 of concrete are supplemented respectively by the solutions of copolymers A, B and C prepared as described above.

For the preparation of the concrete formulations 2 to 4 respectively incorporating the copolymers A, B and C, the amount of water added is imposed so that the three hydraulic compositions adjuvanted have the same reduction in water (30%) compared to control concrete.

The proportions of each of the constituents of the hydraulic compositions thus prepared are shown in Table 1 below.

2. Evaluation of hydraulic compositions

The compositions are evaluated for their properties of initial fluidity (T0 maneuverability), air capture, water reduction and compressive strength at 1 day, according to the following protocols.

Measurement of maneuverability at T0

The measurement of the initial fluidity (or maneuverability at T0) is carried out, at ambient temperature, by means of a tapered frustoconical cone made of galvanized steel, called the Abrams cone, according to the 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 plate moistened with a sponge.

The cone is then filled with a determined quantity of each of the preparations. The filling lasts 2 minutes. The contents of the cone are packed with a metal rod. As soon as the filling is completed, the cone is lifted vertically, which leads to the collapse of its contents on the plate.

The diameter of the slab thus formed is measured after 30 seconds.

Concretes can be classified according to their maneuverability according to EN 206-1. In particular, it may be considered that concretes having a spread of less than or equal to 60 mm have equivalent consistencies.

Measuring air capture

The measurement of air capture is in accordance with EN 12350-7, paragraph 3.3.

Measuring water reduction

It is measured according to the standard ADJUVANT NF EN 934-2.

Measurement of compressive strength

The 1-day compressive strength measurements are carried out according to EN 12390-3, paragraph 3. The compressive strength is expressed in MPa.

The tests were performed on a Class 1 test machine according to EN 12390-4.

The results obtained for the various hydraulic compositions are indicated in the following Table 1.

Table 1

The set of hydraulic compositions has a homogeneous appearance, without segregation of the constituents.

The implementation of copolymers B and C according to the invention provides access to high compressive strengths 1 day, while maintaining an initial consistency (maneuverability T0) satisfactory.

In particular, it is demonstrated that the copolymers B and C according to the invention make it possible, for the same water reduction of the hydraulic composition, to obtain improved 1-day strengths (respectively about 5% and 24%), compared with to the implementation of the copolymer A not according to the invention, while maintaining a good maneuverability of the hydraulic composition.

Claims

Use for increasing the mechanical strength at young ages of a hydraulic composition of at least one copolymer obtained by polymerization from a monomer mixture comprising:

at least one monomer (b) of formula (I) below:

H ₂ C = C (- R 1) - (CH ₂ ) _P - O - [(EO) - (PO) _m ] - H (I) in which:

R 1 represents a hydrogen atom or a CH _{3j group}

p is 1 or 2,

2. Use according to claim 1, to obtain a resistance of the hydraulic compression composition to 1 day, measured according to the EN 12390-3 standard, greater than or equal to 155%, in particular greater than or equal to 160%, especially greater or equal to 170% and more particularly greater than or equal to 180% of the value of the strength of the hydraulic composition free of said copolymer (s).

3. Use according to any one of the preceding claims, wherein said copolymer (s) being used in a proportion of from 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.

4. Use according to any one of the preceding claims, characterized in that the monomer (s) (s) (b) have the following formula (Γ):

H ₂ C = C (- Ri) - CH ₂ - O - [(EO) "- (PO) _m] - H (Γ) wherein Ri, n and m are as defined in claim 1.

5. Use according to any one of the preceding claims, characterized in that said copolymer is obtained from at least one monomer (b) of formula (II) below:

H ₂ C = C (CH ₃₎ - CH ₂ - O - [(EO) "- (PO) _m] - H (II) wherein n and m are as defined in claim 1.

6. Use according to any one of the preceding claims, characterized in that said copolymer is obtained from at least one monomer (b) of formula (III) below:

m and n being as defined in claim 1.

7. Use according to any one of the preceding claims, characterized in that the molar proportion of 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. 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 150. and 110 and more particularly between 20 and 70.

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

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

11. Use according to any one of the preceding claims, characterized in that said copolymer is obtained by polymerization from a monomer mixture comprising, besides the said anionic monomer (s) (a) and the or said monomer (s) (b) of formula (I), one or more monomers (s) (c) chosen from:

2-acrylamino-2-methylpropanesulphonic acid (AMPS),

vinylsulphonates, in particular sodium styrene sulphonate,

- the amines,

acrylamide or methacrylamide,

phosphonic monomers, such as vinylphosphonates and alkyl phosphonates,

the macromonomers of formula (VI) below:

Ra - [(EO) _q - (PO) r - (BO) s] - Ra '(VI)

in which :

[(EO) _q - (PO) r - (BO) _s ] represents a polyalkoxylated chain consisting of alkoxylated units, divided into blocks, alternating or random, chosen from ethoxylated units EO, propoxylated units PO and butoxylated units B , q, r and s represent, independently of one another, 0 or an integer ranging between 1 and 250, the sum of m, n and p being between 10 and 250, R _a represents a radical selected from the group consisting of acrylic esters, methacrylic esters and a mixture of these esters and

R _a 'represents hydrogen or an alkyl group having from 1 to 4 carbon atoms,

the hydrophobic monomers of formula (VII) below:

R _b - [(EO) _t - (PO) u - (BO),] - R _b '(VII) in which :

Rb 'represents an alkyl group having from 8 to 40 carbon atoms and

crosslinking monomers.