Patent Application
20190264019
The invention relates to a method for the preparation in water of a polymer, comprising the preparation of an emulsion comprising a copolymer of HASE type and a mixture of a monomer comprising at least one polymerizable olefinic unsaturation and of a radical-generating compound, followed by the polymerization of the emulsified monomer by heating at a temperature greater than the temperature required for the polymerization reaction. The invention also relates to the polymer prepared and to its use.
Although there exist methods for the preparation of polymers in water, the methods of the state of the art do not always make it possible to provide a satisfactory solution to the problems encountered.
In particular, the methods of the state of the art for the preparation of polymers in emulsion require the use of large amounts of surface-active compounds.
Furthermore, the known methods do not always make it possible to control the size of the emulsified monomer particles or the size of the particles of monomer which is prepared.
The methods for the preparation of polymers in an aqueous medium of the state of the art do not always make it possible to result in high levels of solids content.
There thus exists a need to have available improved methods for the preparation of polymers in water.
The method according to the invention makes it possible to provide a solution to all or some of the problems of the methods of the state of the art.
Thus, the invention provides a method for the preparation in water of a polymer (P1) comprising:
Advantageously, the method according to the invention can be used with reduced or very reduced amounts of surface-active compound (less than 5% by weight of monomer, preferably less than 3% by weight or less than 1% by weight of monomer), indeed even in the absence of surface-active compound.
During the implementation of steps (a) and (b) of the method according to the invention, droplets of monomer (b1) are dispersed by means of the copolymer (P2) of HASE type. During the polymerization (c), the droplets of polymer (P1) are also dispersed by means of the copolymer (P2).
Particularly advantageously, the droplets formed during the implementation of the method according to the invention have a controlled size. Preferably, the droplets of monomer (b1) or of polymer (P1) have a size ranging from 50 nm to 50 μm, more preferably from 50 nm to 500 nm or from 1 μm to 50 μm. The size of the droplets of monomer (b1) or of polymer (P1) can also range from 50 nm to 1 μm or from 500 nm to 50 μm.
For the method according to the invention, the emulsion of monomer (b1) or of polymer (P1) which is prepared by means of the copolymer (P2) of HASE type has a solids content which can vary fairly widely. Preferably, this solids content ranges from 10% by weight to 50% by weight, preferably from 15% by weight to 45% by weight or from 20% by weight to 40% by weight of emulsion.
The copolymer (P2) used by the method according to the invention may generally be known as such. This copolymer (P2) is a polymer of HASE (Hydrophobically modified Alkali-Soluble Emulsion) type which is rendered soluble by a basic treatment. It is a linear or cross-linked acrylic copolymer comprising acid groups and hydrophobic groups. Such a copolymer of HASE type results from the copolymerization of anionic monomers, such as acrylic or methacrylic acids, of hydrophobic non-ionic monomers and of hydrophobic associative macromonomers. At low pH, generally of less than 5, and without the addition of a base, the acrylic copolymer of HASE type is insoluble in water and is present in the form of a latex. During the addition of a base, the anionic groups are partially or completely neutralized and the copolymer dissolves in the water.
Preferably, for the method according to the invention, the polymer (P2) of HASE type is obtained by a polymerization reaction:
R1-(EO)m—(PO)n—R2 (I)
During the preparation of the polymer (P2), besides the comonomers (a1), (a2) and (a3), the polymerization reaction of the method according to the invention can use one or more other monomer(s).
Preferably, another monomer which can be used during the preparation of the polymer (P2) is a compound (a4) chosen from 2-acrylamido-2-methylpropanesulfonic acid, ethoxymethacrylate sulfonic acid, sodium methallylsulfonate, styrenesulfonate and their salts.
The amount of monomer (a4) can vary fairly widely. Preferably, the reaction for the preparation of the polymer (P2) uses from 0.1% by weight to 7% by weight, preferably from 0.5% by weight to 5% by weight, more preferably from 1% by weight to 3% by weight, of monomer (a4), based on the total amount by weight of monomer.
Preferably again, another monomer which can be used during the preparation of the polymer (P2) is a cross-linking compound (a5).
Advantageously, according to the invention, the monomer (a5) is a compound comprising at least two reactive functional groups, in particular two polymerizable olefinic unsaturations. The monomer (a5) is preferably chosen from monomers comprising at least two olefinic unsaturations. More preferably, the monomer (a5) is a compound comprising at least two ethylenic unsaturations. Such monomers (a5) are known as such.
Mention may be made, as monomers (a5), of cross-linking unsaturated monomers, for example polyunsaturated aromatic monomers, such as divinylbenzene, divinylnaphthalene and trivinylbenzene, polyunsaturated alicyclic monomers, for example 1,2,4-trivinylcyclohexane, difunctional esters of phthalic acid, such as diallyl phthalate, polyalkenyl ethers, such as triallyl pentaerythritol, diallyl pentaerythritol, diallyl sucrose, octaallyl sucrose and trimethylolpropane diallyl ether, polyunsaturated esters of polyalcohols or of polyacids, such as 1,6-hexanediol di(meth)acrylate, tetramethylene tri(meth)acrylate, allyl acrylate, diallyl itaconate, diallyl fumarate, diallyl maleate, trimethylolpropane tri(meth)acrylate, trimethylolpropane di(meth)acrylate, poly(alkyleneoxy) glycol di(meth)acrylates and polyethylene glycol di(meth)acrylate, alkylenebisacrylamides, such as methylenebisacrylamide and propylenebisacrylamide, hydroxy or carboxy derivatives of methylenebisacrylamide, such as N,N′-bis(methylol)methylenebisacrylamide, polyalkylene glycol di(meth)acrylates, such as ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, allyl methacrylate, ethylene glycol dimethacrylate, butylene glycol dimethacrylate, pentaerythritol di-, tri- and tetraacrylates, poly(alkyleneoxy) glycol di(meth)acrylates, such as polyethylene glycol diacrylates, bisphenol A diacrylates, butanediol dimethacrylate, 2,2-dimethylpropanediol dimethacrylate, phenylene diacrylate and their mixtures.
Mention may also be made, as monomer (a5), of a compound of formula (II):
in which:
Mention may also be made, as other monomer (a5), of a compound of formula (III):
in which R4 represents —C(H)═CH2, —C(CH3)═CH2, —C(H)═C(H)C(O)OH, —C(H)═C(H)CH3, —C(═CH2)CH2C(O)OH, —CH2C(═CH2)C(O)OH.
Mention may again be made, as monomer (a5), of a compound of formula (IV):
H2C═C(R5)CH2—(OL2)q-O—C(═O)R6 (IV)
in which:
The amount of monomer (a5) can also vary fairly widely. Preferably, the reaction for the preparation of the polymer (P2) uses from 0.01% by weight to 5% by weight, preferably from 0.05% by weight to 3% by weight, more preferably from 0.05% by weight to 1% by weight, of monomer (a5), based on the total amount by weight of monomer.
Preferably, for the method according to the invention, the copolymer (P2) of HASE type is partially neutralized by means of a base, for example by means of an alkali metal derivative or of an alkaline earth metal derivative. The preferred bases are chosen from NaOH, KOH, NH4OH, Ca(OH)2, monoisopropylamine (AMP), triethylamine, diethylamine, monoethylamine.
The method according to the invention also comprises the addition, with stirring and at a temperature of less than 40° C., of at least one monomer (b1) comprising at least one polymerizable olefinic unsaturation and of at least one radical-generating compound (b2). Advantageously, according to the invention, the solubility in water of the monomer (b1) makes it possible to obtain an emulsion during the mixing with stirring in the copolymer (P2). Thus, a dispersion of nanometric droplets of monomer (b1) in water is formed. Preferably, for the method according to the invention, the monomer (b1) is a non-ionic monomer, preferably a non-ionic monomer comprising at least one polymerizable olefinic unsaturation, especially a polymerizable ethylenic unsaturation and in particular a polymerizable vinyl group.
More preferably, the monomer (b1) is a non-ionic monomer chosen from the esters of an acid comprising at least one monocarboxylic acid group, especially an ester of an acid chosen from acrylic acid, methacrylic acid, an acrylic acid salt, a methacrylic acid salt and their mixtures.
Preference is given, as examples of monomer (b1), to a compound chosen from styrene, vinylcaprolactam, alkyl acrylate, especially C1-C10 alkyl acrylate, preferably C1-C4 alkyl acrylate, more preferably methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, n-butyl acrylate, alkyl methacrylate, especially C1-C10 alkyl methacrylate, preferably
C1-C4 alkyl methacrylate, more preferably methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, aryl acrylate, preferably benzyl acrylate, phenoxyethyl acrylate, aryl methacrylate, preferably phenyl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate. The monomers (b1) which are particularly preferred are methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isobutyl methacrylate and n-butyl methacrylate.
Step (b) according to the invention uses at least one radical-generating compound (b2). It can be soluble in water or else soluble in the organic phase, in particular in the monomer (b1).
Preferably, for the method according to the invention, the radical-generating compound (b2) of use as initiating compound for the polymerization reaction is an azo compound. More preferably, the radical-generating compound (b2) is a compound chosen from azobisisobutyronitrile (AZDN or AIBN), a peroxide compound, preferably benzoyl peroxide, benzoyl hydroperoxide and their mixtures. Mention may also be made of alkali metal persulfates, especially sodium persulfate and potassium persulfate, ammonium persulfate, partially water-soluble peroxides, especially persuccinic acid, t-butyl hydroperoxide, cumyl hydroperoxide, persulfates combined with a ferrous ion, with a sulfite ion or with a bisulfite ion, and their mixtures.
According to the invention, the radical-generating compound (b2) can be combined with at least one controlled radical polymerization transfer agent, in particular a transfer agent of RAFT (Reversible Addition-Fragmentation chain Transfer) type, for example a xanthate derivative, preferably dipropyl trithiocarbonate (DPTTC or disodium 2,2′-(thiocarbonylbisthio)dipropanoate—CAS No. 864970-33-2), n-dodecyl mercaptan. Preferably, during the implementation of the method according to the invention, the radical-generating compound (b2), preferably a hydrophobic radical-generating compound (b2), and the monomer (b1) are added in the form of a mixture.
Preferably again, during the implementation of the method according to the invention, the radical-generating compound (b2), preferably a hydrophilic radical-generating compound (b2), and the monomer (b1) are added separately or successively, preferably the radical-generating compound (b2) then being added after the monomer (b1).
During the polymerization reaction of the monomer (b1), besides the compounds (b1) and (b2), the polymerization reaction of the method according to the invention can use one or more other monomer(s).
Preferably, another monomer which can be used during the polymerization of the monomer (b1) is a monomer chosen from:
More preferably, according to the invention, the monomer (b3) is chosen from hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, N-isopropylacrylamide.
More preferably, according to the invention, the monomer (b4) is methacrylic acid.
According to the invention, the amount by weight of monomer (b4) used is less than the amount by weight of monomer (b1).
The amount of monomer (b5) can vary fairly widely. Preferably, the reaction for the polymerization of the monomer (b1) can use from 0.1% by weight to 7% by weight, preferably from 0.5% by weight to 5% by weight, more preferably from 1% by weight to 3% by weight, of monomer (b5), based on the total amount by weight of monomer.
Preferably again, another monomer which can be used during the polymerization of the monomer (b1) is generally a cross-linking compound (b6).
Advantageously, according to the invention, the monomer (b6) is a compound comprising at least two reactive functional groups, in particular two polymerizable olefinic unsaturations. The monomer (b6) is preferably chosen from monomers comprising at least two olefinic unsaturations. More preferably, the monomer (b6) is a compound comprising at least two ethylenic unsaturations. Such monomers (b6) are known as such.
Mention may be made, as monomer (b6), of the monomers defined as specific monomers (a5) according to the invention.
The amount of monomer (b6) can also vary fairly widely. Preferably, the reaction for the polymerization of the monomer (b1) can use from 0.01% by weight to 5% by weight, preferably from 0.05% by weight to 3% by weight, more preferably from 0.05% by weight to 1% by weight, of monomer (b6), based on the total amount by weight of monomer.
For the method according to the invention, the temperature of steps (a) and (b) is less than 40° C. in order to prevent the polymerization of the monomer (b1). Advantageously, the temperature of steps (a) and (b), which is identical or different, can be less than 35° C. or be less than 25° C.
During the implementation of the method according to the invention, the heating of step (c) makes it possible to carry out the polymerization of the monomer (b1). Preferably, for the method according to the invention, the temperature of step (c) is greater than 60° C., preferably greater than 70° C.
When several monomers (b1) are used, this heating makes it possible to carry out the copolymerization of these monomers (b1). In the same way, when several monomers (b1) and (b3) to (b6) are used, this heating makes it possible to carry out the copolymerization of these monomers (b1) and (b3) to (b6).
The invention also relates to the polymer (P1) capable of being prepared according to the invention.
Advantageously, the method according to the invention can make it possible to prepare an emulsion within which the monomer (b1) is surrounded by the copolymer (P2) of HASE type. The droplets of monomer (b1) then constitute as many polymerization nanoreactors or microreactors. During the polymerization of the monomer (b1) emulsified in the form of droplets surrounded by copolymer (P2), the polymer (P1) formed can then also be in the form of droplets surrounded by copolymer (P2). A core/shell composite can thus be prepared during the implementation of the method according to the invention.
The invention thus also relates to a composite comprising at least one polymer (P1) prepared according to the invention surrounded by copolymer (P2) of HASE type used according to the invention. The specific, advantageous or preferred characteristics of the method according to the invention or of the polymer (P1) according to the invention define as many composites according to the invention which are specific, advantageous or preferred.
The examples which follow make it possible to illustrate the different aspects of the invention.
A mixture of water, of copolymer (P2) of HASE type, of a base (95% by weight monoisopropylamine) and, if appropriate, of an amphiphilic compound (Disponil G625, Cognis) is prepared in a stirred reactor at a temperature of 25° C. The copolymers (P2) of HASE type used are:
A mixture of monomer (b1) and of radical-generating compound (b2) is added with stirring at a temperature of 25° C. in order to prepare an emulsion of monomer (b1) by means of the copolymer (P2). An aqueous solution of gluconolactonic acid is then added with stirring and at a temperature of 25° C.
Finally, heating is carried out with stirring at a temperature of 70° C. for 2 hours. The medium is then cooled and the polymer (P1) according to the invention is obtained. The reactants and the proportions (g) used and also the properties of the polymers according to the invention obtained are presented in Table 1.
A mixture of water, of copolymer (P2) of HASE type, of a base (95% by weight monoisopropylamine) and, if appropriate, of an amphiphilic compound (Disponil G625, Cognis) is prepared in a stirred reactor at a temperature of 25° C. The copolymer (P2) of HASE type used is the copolymer (P2-1).
The monomers (b1) and then the radical-generating compound (b2) are added with stirring at a temperature of 25° C. in order to prepare an emulsion of monomer (b1) by means of the copolymer (P2).
An aqueous solution of gluconolactonic acid is then added with stirring and at a temperature of 25° C.
Finally, heating is carried out with stirring at a temperature of 70° C. for 2 hours. The medium is then cooled and the copolymer (P1) according to the invention is obtained.
The reactants and the proportions used and also the properties of the copolymers according to the invention are presented in Table 2.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1660345 | Oct 2016 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2017/052883 | 10/20/2017 | WO | 00 |
