AQUEOUS DISPERSION OF POLYMER MADE FROM MULTISTRUCTURED PARTICLES FOR AQUEOUS COATINGS HAVING IMPROVED BLOCKING AND FINGERPRINT RESISTANCE AND HARDNESS

• US 20160289489A1
• Filed: 11/12/2014
• Published: 10/06/2016
• Est. Priority Date: 11/15/2013
• Status: Active Grant

• Current Assignee: Arkema France (Arkema)
• Original Assignee: Arkema France (Arkema)
• Inventors: BETREMIEUX, Isabelle, BOONE, Alain, LOZE, Jean-Yves
• Granted Patent: US 10,035,923 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 285/00 Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• CPC Class Codes: C08L 51/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C08L51/04, C08L51/06 take precedence
• CPC Class Codes: C09D 151/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09D151/04, C09D151/06 take precedence

Abstract

The invention relates to a crosslinkable or non-crosslinkable aqueous dispersion of polymer, based on structured polymer particles, said particle comprising a core polymer phase, based on a polymer P1 with Tg1 ranging from 60 to 120° C., a second polymer phase enveloping said core, based on a polymer P2 with a Tg2 ranging from −60 to 40° C. and a third outer polymer phase (or shell based on a polymer P3, with a Tg3 greater than Tg2 not exceeding 120° C. and having a measured Mn of from 1000 to 150 000, with the weight contents of said polymers P1, P2 and P3 being relative to the total weight of polymer (P1+P2+P3): P1 from 5% to 60%, P2 from 40% to 85%, P3 from 5% to 25% with the sum of said weight contents being 100%.

Claims

1. An aqueous dispersion of polymer based on multi-structured polymer particles having at least 3 different polymer phases wherein said particle comprises:

a polymer phase as core, based on polymer P1 derived from the emulsion polymerization of a monomer composition M1, with P1 having a glass transition temperature Tg1, calculated according to Fox, from 60 to 120°

C.,

a second polymer phase enveloping said core, based on a polymer P2 derived from the emulsion polymerization of a monomer composition M2, with P2 having a glass transition temperature Tg2 calculated according to Fox from −

60 to 40°

C.,

a third outer polymer phase which shell enveloping said phase P2, based on a polymer P3 derived from the emulsion polymerization of a monomer composition M3, with P3 having a glass transition temperature Tg3, calculated according to Fox, higher than Tg2, more than 5°

C. higher and not exceeding 120°

C., and a number-average molecular mass Mn not exceeding 150,000,

with the weight contents relative to the total weight of polymer P1+P2+P3 being for;

P1 from 5% to 60%,

P2 from 40% to 85%,

P3 from 5% to 25%,

and the sum of said weight contents (P1+P2P3) being equal to 100%.

2. The dispersion as claimed in claim 1, that wherein said emulsion polymerization of said composition M1 is performed in the presence of three anionic surfactants, at least two of which are different, with the presence of an anionic surfactant in a seed monomer composition M0 and of two surfactants in a monomer composition M′

1 with the overall composition derived from M0 and M′

1 corresponding to said monomer composition M1 and in that said emulsion polymerization of said composition M2 is performed in the presence of at least two surfactants, one of which is nonionic, chosen from the group consisting of alkoxylated fatty alcohols, and the other being anionic and optionally being identical or different relative to one of the two surfactants defined for M1.

3. The dispersion as claimed in claim 2, wherein at least one of said anionic surfactants in M1 and M2 is a sulfosuccinate.

4. The dispersion as claimed in claim 1 wherein said composition M2 and consequently said polymer P2 derived from M2 comprises at least one water-soluble transfer agent.

5. The dispersion as claimed in claim 1 wherein said composition M3 and consequently said polymer P3 derived from M3 comprises at least two transfer agents, of which one is water-soluble and one is liposoluble.

6. The dispersion as claimed in claim 5, wherein the weight ratio of (pure) water-soluble transfer agent to (pure) liposoluble transfer agent for all the phases P2 and P3 (P2+P3) is less than 2.

7. The dispersion as claimed in claim 1 wherein said composition M3 from which P3 is derived and optionally said composition M2 from which P2 is derived comprise at least one ethylenically unsaturated monomer bearing, in addition to its ethylenic unsaturation, at least one functional group X selected from the group consisting of:

acetoacetoxy, diacetone, methylolsilane, alkoxysilane, carboxy/anhydride, hydroxy, amine, epoxy (or oxirane), phosphate, phosphonate, phosphinate, sulfate, sulforiate, amide, imide, aziridine, oxazoline, imidazole, cyclic carbonate, benzophenone, ureido, provided that, in the case of the presence of more than one monomer bearing a functional group X, said groups X cannot react together during the preparation of said dispersion or during storage.

8. The dispersion as claimed in claim 7, wherein monomer bearing a group X is chosen as follows per group X:

for carboxy/anhydride;

(meth)acrylic acid, itaconic acid/anhydride, fumaric acid, maleic anhydride, tetrahydrophthalic (TIP) acid/anhydride

for hydroxy;

hydroxyalkyl(meth)acrylates, with C₂ to C₄ alkyl, which are optionally alkoxylated, in particular alkoxylated or non-alkoxylated hydroxyethyl(meth)acrylate (HE(M)A), hydroxypropyl(meth)acrylate (HP(M)A), hydroxybutyl(meth)acrylate HB(M)A

for epoxy;

GLYMA glycidyl(meth)acrylate, (meth)acrylate hearing an epoxidized cycloaliphatic group from among epoxidized dicyclopentenyl, epoxidized cyclohexenyl, epoxidized tetrahydrophthalic and epoxidized norbornenyl

for amine;

aminoalkyl(meth)acrylates or aminoalkyl(meth)acrylamides with C₂ to C₄ alkyl, DMAEMA (dimethyl aminoethyl methacrylate), and TBAEMA (t-butylaminoeth ylmethacrylate)

for amide;

(meth)acrylamide

for imide;

maleimide

for cyclic carbonate;

glyceryl(meth)acrylate carbonate

for phosphate;

optionally alkoxylated phosphate mono- and/or diesters of hydroxyalkyl(meth)acrylates

for phosphonate;

optionally alkoxylated phosphonate esters of hydroxyalkyl(meth)acrylates

for phosphinate;

optionally alkoxylated esters of hydroxyalkyl(meth)acrylates with phosphinic acid

for sulfate;

hydroxyalkyl(meth)acrylate esters, optionally with alkoxylated alkyl

for sulfonate;

optionally alkoxylated sulfonate esters of hydroxyalkyl(meth)acrylates or of hydroxyalkyl(meth)aerylamides, sulfonates such as hydroxyethyl(meth)acrylate sulfonate or acrylamide propane sulfonate (in acid or salt form)

for imidazole;

2-ethyl-(2-oxoimidazolidin-1-yl) methacrylate

for ureido;

N-(2-methacryloyloxyethyl)ethyleneurea

for oxazoline;

hydroxyalkyl 2-oxazoline(meth)acrylates

for benzophenone;

benzophenone(meth)acrylate

for aziridine;

1-(2-hydroxyethyl)aziridine methacrylate

for acetoacetoxy;

acetoacetoxyethyl(meth)acrylate (AAEM)

for diacetone;

diacetoneacrylamide (DAAM)

for methylol;

N-methylolacrylamide (NMA)

for alkoxysilane;

alkoxysilane(meth)acrylates.

9. The dispersion as claimed in claim 7 wherein said group X is a reactive group chosen from the group consisting of:

acetoacetoxy, diacetone, N-methylol, and alkoxysilane, with the preferred monomers bearing said group X being chosen from the group consisting of acetoacetoxyethyl(meth)acrylate (AAEM), diacetonediacrylainide (DAAM), N-methylolacrylamide and alkoxysilane(meth)acrylates.

10. The dispersion as claimed in claim 7 wherein said group X is chosen from the group consisting of:

carboxy/anhydride, hydroxy, amine, epoxy (or oxirane), imide, aziridine, oxazoline, imidazole and cyclic carbonate.

11. The dispersion as claimed in claim 7 wherein the index of groups X expressed in mmol/g of polymer (polymer:

P1+P2+P3) ranges from 0.002 to 0.5.

12. The dispersion as claimed in claim 1 wherein said polymers P1, P2 and P3 are derived, respectively, from said monomer compositions M1, M2 and M3, consisting of (meth)acrylic monomers or of mixtures of (meth)acrylic monomers with at least one vinyl aromatic monomer.

13. The dispersion as claimed in claim 1 wherein said polymer P1 is derived from a monomer composition M1 comprising at least one monomer as internal crosslinking agent.

14. A process for preparing a dispersion according to claim 1 comprising emulsion polymerization steps:

i) a seeding step comprising emulsion prepolymerization of a seed monomer composition M0, with the seed particles having a size of less than or equal to 40 nm and representing a weight content ranging from 2% to 25% of the weight of said polymer phase P1,

ii) a step of emulsion polymerization of a monomer composition M′

1 giving a polymer P′

1 thus constituting with the seed polymer P0 obtained in step i) said polymer phase P1 of said particle core, said monomer composition M1 being identical to or different from said seed composition M0 (if identical to M0, it corresponds to that of said monomers M1) and their overall weight-average composition (M0 +M′

1) corresponding to that of said monomers M1, the product of this step ii) (dispersion) optionally being able to be stored and used at a later time, as starting material for the following step iii),

iii) a step of emulsion polymerization of a monomer composition M2 giving rise to said polymer phase P2, said step iii) comprising at the start a seeding and optionally in the presence of a water-soluble transfer agent,

iv) a step of emulsion polymerization of a monomer composition M3 giving rise to said polymer phase P3, optionally in the presence of two transfer agents, one water-soluble and the other liposoluble, so as to obtain said polymer P3 as an outer layer.

15. The process as claimed in claim 14, characterized in that:

the seeding step i) is performed in the presence of from 0.01% to 0.5% by weight of an anionic surfactant relative to the total weight of P1+P2+P3

the step of emulsion polymerization ii) of the monomer composition M′

1 is performed in the presence of from 0.1% to 3% by weight, relative to the total weight of P1+P2+P3, of a first anionic surfactant which is identical to or different from that of the seed M0, and of a second anionic surfactant different from the first of this step ii), with the weight content of these two anionic surfactants of phase P1 being from 0.1% to 3% relative to the total weight of P1P2+P3

the step of emulsion polymerization iii) of the monomer composition M2 is performed in the presence of from 0.1% to 3% by weight, relative to the total weight of P1+P2+P3, of at least two surfactants a) and b) with a) being a first nonionic surfactant chosen from alkoxylated fatty alcohols, and b) being an anionic surfactant which may be identical to or different from those of step ii), with said step iii) comprising at the start a seeding and optionally (for said step iii)) in the presence of at least one water-soluble transfer agent,

the step of polymerization iv) of said composition M3 is performed in the presence or absence of surfactants and if in the presence of surfactants, under the same conditions as those of step iii) and optionally in the presence of at least two transfer agents, of which one is water-soluble and one is liposoluble.

16. The process as claimed in claim 14 wherein:

steps i) and ii) are performed at a temperature of from 75 to 90°

C.

the step of polymerization iii) of said monomer composition M2, like the step of polymerization iv) of said monomer composition M3, is performed at a temperature below Tg1, when said process is performed at atmospheric pressure.

17. The process as claimed in claim 14 wherein step ii) of emulsion polymerization of the overall composition M1, giving the polymer P1, and step iii) of emulsion polymerization of said composition M2 giving the polymer P2 are continued to a degree of conversion of at least 95% before addition of said monomer composition M3.

22. A coating composition comprising at least one aqueous dispersion as defined in claim 1.

24. The composition as claimed in claim 16 comprising in addition to said dispersion, at least one crosslinking agent bearing at least two groups that are reactive with said groups X of said polymer of said dispersion.

25. The composition as claimed in claim 22 which does not comprise coalescer.

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