WATER-SOLUBLE COPOLYMER COMPOSITION

Abstract

The present invention relates to the field of water-soluble or water-dispersible copolymers comprising at least one random copolymer comprising styrene, methacrylic acid, acrylic acid and butyl acrylate.

Claims

1. A composition comprising a random copolymer comprising the following monomers: styrene, from 28% to 45% by weight, limits included; methacrylic acid, from 10% to 40% by weight, limits included; acrylic acid, from 0.5% to 5% by weight, limits included; butyl acrylate, from 18% to 35% by weight, limits included.

2. The composition as claimed in claim 1, wherein the random copolymer is prepared by controlled radical polymerization.

3. The composition as claimed in claim 1, wherein the weight-average molecular weight of the copolymer(s) is between 30 000 and 300 000 g/mol.

4. The composition as claimed in claim 1, wherein the glass transition temperature, measured by DMA, is greater than 60° C.

5. The composition as claimed in claim 2, wherein the polymerization is carried out by controlled radical polymerization of RAFT type.

6. The composition as claimed in claim 2, wherein the polymerization is carried out by controlled radical polymerization of ATRP type.

7. The composition as claimed in claim 2, wherein the polymerization is carried out by controlled radical polymerization of NMP type.

8. The composition as claimed in claim 7, wherein the nitroxide results from the alkoxyamines derived from the stable radical (1): ##STR00003## wherein the radical R.sub.L exhibits a molar mass of greater than 15.0342 g/mol.

9. The composition as claimed in claim 8, wherein the alkoxyamines are derived from the following stable radicals: N-(tert-butyl)-1-phenyl-2-methylpropyl nitroxide, N-(tert-butyl)-1-(2-naphthyl)-2-methylpropyl nitroxide, N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide, N-(tert-butyl)-1-dibenzylphosphono-2,2-dimethylpropyl nitroxide, N-phenyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide, N-phenyl-1-diethylphosphono-1-methylethyl nitroxide, N-(1-phenyl-2-methylpropyl)-1-diethylphosphono-1-methylethyl nitroxide, 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy, 2,4,6-tert-butyl)phenoxy nitroxide, N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide.

10. The composition as claimed in claim 9, wherein the alkoxyamines are derived from N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide.

11. The use of a composition as claimed in claim 1 as dispersing agents for pigments, as rheology modifiers in drilling muds, textile printing pastes, the cosmetics industry, the detergents industry, and other coating compositions, as anti-settling and/or suspending agents for coarse inorganic or organic fillers, three-dimensional printing (or 3D printing) of an object of the FDM (fused deposition modeling) type as sacrificial polymer.

12. A filament extruded from a composition of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 illustrates the dissolution of a control copolymer and the test 1, test 2 and test 3 copolymers of the invention at pH=12 and 60° C.

DETAILED DESCRIPTION OF THE INVENTION

[0018] Dissolution or dispersibility in water is understood to mean a dissolution or a dispersibility in an aqueous phase, the pH of which is between 5.5 and 14, limits included, preferably between 8 and 12 and more particularly between 8 and 10, limits included, in a temperature range of between 40° C. and 70° C.

[0019] A copolymer is said to be “dispersible” if it forms, at a concentration of 5% by weight in a solvent, at 25° C., a stable suspension of fine, generally spherical, particles. The mean size of the particles constituting said dispersion is less than 1 μm and, more generally, varies between 5 and 400 nm, preferably from 10 to 250 nm, by weight. These particle sizes are measured by light scattering.

[0020] When the solvent is water, the term used is “water-dispersible” copolymer.

[0021] The copolymers of the invention can be prepared by radical polymerization or by controlled radical polymerization. When it is a question of obtaining a water-soluble or water-dispersible copolymer, the applicant company observes, however, that it is preferable to use controlled radical polymerization and that the copolymer thus prepared is more rapidly dissolved or dispersed in aqueous solution.

[0022] To this effect, use may be made of any type of controlled radical polymerization in the context of the invention, such as NMP (“Nitroxide Mediated Polymerization”), RAFT (“Reversible Addition and Fragmentation Transfer”), ATRP (“Atom Transfer Radical Polymerization”), INIFERTER (“Initiator-Transfer-Termination”), RITP (“Reverse Iodine Transfer Polymerization”) or ITP (“Iodine Transfer Polymerization”).

[0023] According to a preferred form of the invention, the copolymers are prepared by nitroxide mediated polymerization (NMP).

[0024] More particularly, the nitroxides resulting from the alkoxyamines derived from the stable free radical (1) are preferred.

##STR00001##

in which the radical R.sub.L exhibits a molar mass of greater than 15.0342 g/mol. The radical R.sub.L can be a halogen atom, such as chlorine, bromine or iodine, a saturated or unsaturated and linear, branched or cyclic hydrocarbon group, such as an alkyl or phenyl radical, or an ester —COOR group or an alkoxyl —OR group or a phosphonate —PO(OR).sub.2 group, provided that it exhibits a molar mass of greater than 15.0342. The radical R.sub.L, which is monovalent, is said to be in the β position with respect to the nitrogen atom of the nitroxide radical. The remaining valencies of the carbon atom and of the nitrogen atom in the formula (1) can be bonded to various radicals, such as a hydrogen atom or a hydrocarbon radical, such as an alkyl, aryl or arylalkyl radical, comprising from 1 to 10 carbon atoms. It is not excluded for the carbon atom and the nitrogen atom in the formula (1) to be connected together via a divalent radical, so as to form a ring. Preferably, however, the remaining valencies of the carbon atom and of the nitrogen atom of the formula (1) are bonded to monovalent radicals. Preferably, the radical R.sub.L exhibits a molar mass of greater than 30 g/mol. The radical R.sub.L can, for example, have a molar mass of between 40 and 450 g/mol. By way of example, the radical R.sub.L can be a radical comprising a phosphoryl group, it being possible for said radical R.sub.L to be represented by the formula:

##STR00002##

in which R.sup.1 and R.sup.2, which can be identical or different, can be chosen from alkyl, cycloalkyl, alkoxyl, aryloxyl, aryl, aralkyloxyl, perfluoroalkyl or aralkyl radicals and can comprise from 1 to 20 carbon atoms. R.sup.1 and/or R.sup.2 can also be a halogen atom, such as a chlorine or bromine or fluorine or iodine atom. The radical R.sub.L can also comprise at least one aromatic ring, such the phenyl radical or the naphthyl radical, it being possible for said ring to be substituted, for example by an alkyl radical comprising from 1 to 4 carbon atoms.

[0025] More particularly, the alkoxyamines derived from the following stable radicals are preferred: [0026] N-(tert-butyl)-1-phenyl-2-methylpropyl nitroxide, [0027] N-(tert-butyl)-1-(2-naphthyl)-2-methylpropyl nitroxide, [0028] N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide, [0029] N-(tert-butyl)-1-dibenzylphosphono-2,2-dimethylpropyl nitroxide, [0030] N-phenyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide, [0031] N-phenyl-1-diethylphosphono-1-methylethyl nitroxide, [0032] N-(1-phenyl-2-methylpropyl)-1-diethylphosphono-1-methylethyl nitroxide, [0033] 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy, [0034] 2,4,6-tert-butyl-phenoxy nitroxide, [0035] N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide.

[0036] The alkoxyamines used in controlled radical polymerization must allow good control of the linking of the monomers. Thus, they do not all allow good control of certain monomers. For example, the alkoxyamines derived from TEMPO make it possible to control only a limited number of monomers; the same is true for the alkoxyamines derived from 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO). On the other hand, other alkoxyamines derived from the nitroxides corresponding to the formula (1), particularly those derived from the nitroxides corresponding to the formula (2) and more particularly still those derived from N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide, make it possible to broaden, to a large number of monomers, the controlled radical polymerization of these monomers.

[0037] In addition, the opening temperature of the alkoxyamines also influences the economic factor. The use of low temperatures will be preferred in order to minimize the industrial difficulties. The alkoxyamines derived from the nitroxides corresponding to the formula (1), particularly those derived from the nitroxides corresponding to the formula (2) and more particularly still those derived from N-(tert-butyl)-1-diethylphosphono-2,2-dimethylpropyl nitroxide will thus be preferred to those derived from TEMPO or 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO).

[0038] The constituent monomers of the copolymers will be chosen from styrene, methacrylic acid, acrylic acid and butyl acrylate.

[0039] The proportion by weight of the monomers is chosen in the following ranges: [0040] styrene, from 28% to 45% by weight, preferably from 28% to 40%, limits included; [0041] methacrylic acid, from 10% to 40% by weight, preferably between 15% and 36%, limits included; [0042] acrylic acid, from 0.5% to 15% by weight, preferably between 1% and 5%, limits included; [0043] butyl acrylate, from 18% to 35% by weight, preferably from 20% to 30%, limits included.

[0044] The weight-average molecular weight of the water-soluble or water-dispersible copolymers which are a subject matter of the invention is between 30 000 g/mol and 300 000 g/mol, preferably between 70 000 and 170 000 g/mol and more preferably between 80 000 and 130 000 g/mol.

[0045] The dispersity of the water-soluble or water-dispersible copolymers is less than 2.2 and preferably less than 2.

[0046] The glass transition temperature (Tg), measured by DMA (dynamic mechanical analysis), of the random copolymer present in the composition which is a subject matter of the invention is greater than 60° C. and preferably greater than 110° C.

[0047] The water-soluble or water-dispersible compositions which are a subject matter of the invention can contain impact modifiers, whether they are of the random or block copolymer type, or also core-shell particles, alone or in combination.

[0048] The compositions of the invention can be used as dispersing agents for pigments, or also as rheology modifiers in applications as diverse as drilling muds, textile printing pastes, the cosmetics industry, or also the detergents industry, and other coating compositions, such as paint, and as anti-settling and/or suspending agent for coarse inorganic or organic fillers in various fields, such as, for example, the phytosanitary field, but also the field of three-dimensional printing (or 3D printing) of an object of the FDM (fused deposition modeling) type as sacrificial polymer. As such, the compositions of the invention can be formed in the form of an extruded filament, with or without impact modifiers, these extruded filaments also being a subject matter of the invention.

[0049] The invention also relates to the objects obtained by means of the compositions of the invention.

Examples

[0050] The mixture of reactants is as follows: [0051] Initiator: BlocBuilder® (from Arkema); controlled radical polymerization initiator [0052] Styrene (St) (from Aldrich) [0053] Methacrylic acid (MAA) (from Aldrich) [0054] Acrylic acid (AA) (from Aldrich) [0055] Butyl acrylate (BuA) (from Aldrich) [0056] Ethanol (from Aldrich) [0057] Toluene (from Aldrich) [0058] The charging of the reactors is given in table 1

TABLE-US-00001 TABLE 1 Test 1 Test 2 Test 3 Control invention invention invention Initiator 1.7 g 2.1 g 2.1 g 1.5 g Styrene 149.3 187 g 187.9 g 130 g Methacrylic acid 200 g 238.4 g 218.5 g 120 Acrylic acid 0 11.2 g 31.1 g 55.1 g Butyl acrylate 153 g 187 g 188 g 132 g Ethanol 179 g 224 g 224.3 g 160 g Toluene 119 g 150 g 150 g 110 Reactor 110-118° C. 110-118° C. 110-118° C. 110-118° C. temperature

[0059] All of the reagents and solvents are introduced into a closed 2 l stainless steel reactor, under a nitrogen atmosphere. The mixture is heated for 180 minutes, with stirring of 200 rpm.

[0060] The final conversion is 71%.

[0061] The solvents and residual monomers are removed in a vacuum oven at 100° C. The residue obtained is ground in a mortar to be used in the powder form.

GPC Measurements

[0062] The measurement of the masses by size exclusion chromatography (polystyrene standards) leads to the following results (table 2):

TABLE-US-00002 TABLE 2 Test 1 Test 2 Test 3 Control invention invention invention Mn  58 000  59 000  62 000  55 000 Mw 110 000 113 000 110 000 105 000 Mp 108 000 113 000 114 000 105 000 PI   1.9   1.9   1.8   1.9

[0063] The composition of the three copolymers is analyzed by .sup.1H NMR and gives the following results as % by weight, table 3:

TABLE-US-00003 TABLE 3 Test 1 Test 2 Test 3 Control invention invention invention Styrene 37 38.2 38 39 Methacrylic acid 40 34 35 16 Acrylic acid 1.8 3 15 Butyl acrylate 23 26 24 30

Dissolution Tests

[0064] The copolymers obtained are heated to a temperature of 160° C. under a compression molding press to form a pellet with a diameter of 2.5 cm and a thickness of 1 mm. The pellets are subsequently placed in a beaker, with stirring, in an alkaline medium (buffer solution) at a temperature of 60° C.

[0065] The samples are periodically removed and weighed in order to evaluate the weight loss as % linked to the dissolution of the copolymer. The tests are carried out at a pH of 12 at 60° C.

TABLE-US-00004 TABLE 4 Weight loss % Time Test 1 Test 2 Test 3 (min) Control invention invention invention 0 0 0 0 0 10 18 34 34 32 20 30 56 62 94 30 61 82 87 100 40 83 100 100 100

[0066] The dissolution of the control copolymers the copolymers of the control, the invention test 1, 2 and 3 at pH=12 and 60° C. is displayed in FIG. 1.

[0067] It is observed that the copolymers prepared using the four monomers St/MAA/AA/BuA (invention) dissolve more quickly than those prepared without acrylic acid while having a proportion of hydrophilic monomers (MAA+AA) which is slightly lower in molar proportion.