Nanoparticles

• US 20070154709A1
• Filed: 12/15/2004
• Published: 07/05/2007
• Est. Priority Date: 01/27/2004
• Status: Abandoned Application

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Muellen, Klaus, Koch, Matthias, Klapper, Markus, Khrenov, Victor
• Application Number:
  US10/587,299
• Publication Number:
  US 20070154709A1
• Time in Patent Office: Days
• US Class Current: 428/379
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/14 Methods for preparing oxides or hydroxides in general particular individual oxides or hydroxides, see the relevant groups of subclasses C01B - C01G or C25B, according to the element combined with the oxygen or hydroxy group
• CPC Class Codes: C01B 13/32 by oxidation or hydrolysis of elements or compounds in the liquid or solid state or in non-aqueous solution, e.g. sol-gel process
• CPC Class Codes: C01G 9/02 Oxides; Hydroxides
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C09C 1/043 Zinc oxide
• CPC Class Codes: C09C 3/10 Treatment with macromolecular organic compounds C09C3/006 takes precedence
• CPC Class Codes: Y10T 428/294 including metal or compound thereof [excluding glass, ceramic and asbestos]

Abstract

The invention relates to polymer-modified nanoparticles which are suitable as UV stabilisers in polymers, characterised in that they are obtainable by a process in which, in a step a), an inverse emulsion comprising one or more water-soluble precursors of the nanoparticles or a melt is prepared with the aid of a random copolymer of at least one monomer containing hydrophobic radicals and at least one monomer containing hydrophilic radicals, and, in a step b), particles are produced, and to the use thereof for UV protection in polymers.

Claims

1. Polymer-modified nanoparticles which are suitable as UV stabilisers in polymers, characterised in that they are obtainable by a process in which, in a step a), an inverse emulsion comprising one or more water-soluble precursors of the nanoparticles or a melt is prepared with the aid of a random copolymer of at least one monomer containing hydrophobic radicals and at least one monomer containing hydrophilic radicals, and, in a step b), particles are produced.

2. Nanoparticles according to claim 1, characterised in that the particles essentially consist of oxides or hydroxides of silicon, cerium, cobalt, chromium, nickel, zinc, titanium, iron, yttrium and/or zirconium.

3. Nanoparticles according to claim 1, characterised in that the particles have a mean particle size, determined by means of dynamic light scattering or transmission electron microscope, of from 3 to 200 nm, preferably from 20 to 80 nm, and very particularly preferably from 30 to 50 nm, and the particle-size distribution is preferably narrow.

4. Nanoparticles according to claim 1, characterised in that the absorption maximum is in the range 300-500 nm, preferably in the range up to 400 nm.

8. Process according to claim 1, characterised in that the droplet size in the emulsion is in the range from 5 to 500 nm, preferably in the range from 10 to 200 nm.

9. Process according to claim 1, characterised in that a second emulsion in which a reactant for the precursors is in emulsified form is mixed in step b) with the precursor emulsion from step a).

10. Process according to claim 9, characterised in that the two emulsions are mixed with one another by the action of ultrasound.

11. Process according to claim 1, characterised in that the one or more precursors are selected from water-soluble metal compounds, preferably silicon, cerium, cobalt, chromium, nickel, zinc, titanium, iron, yttrium or zirconium compounds, and the precursors are preferably reacted with an acid or lye.

12. Process according to claim 1, characterised in that a coemulsifier, preferably a nonionic surfactant, is employed.

13. Process according to claim 1, characterised in that the weight ratio of structural units containing hydrophobic radicals to structural units containing hydrophilic radicals in the random copolymers is in the range from 1:

2 to 500;

1, preferably in the range from 1;

1 to 100;

1 and particularly preferably in the range from 7;

3 to 10;

1, and the weight average molecular weight of the random copolymers is in the range from M_w=1000 to 1,000,000 g/mol, preferably in the range from 1500 to 100,000 g/mol and particularly preferably in the range from 2000 to 40,000 g/mol.

14. Process according to claim 1, characterised in that the copolymers conform to the formula I

15. Process according to claim 14, characterised in that X and Y, independently of one another, stand for —

O—

, —

C(═

O)—

O—

, —

C(═

O)—

NH—

, —

(CH₂)_n—

, phenylene or pyridyl.

16. Process according to claim 1, characterised in that at least one structural unit contains at least one quaternary nitrogen atom, where R² preferably stands for a —

(CH₂)_m—

(N⁺(CH₃)₂)—

(CH₂)_n—

SO₃⁻

side group or a —

(CH₂)_m—

(N⁺(CH₃)₂)—

(CH₂)_n—

PO₃²⁻

side group, where m stands for an integer from the range from 1 to 30, preferably from the range from 1 to 6, particularly preferably 2, and n stands for an integer from the range from 1 to 30, preferably from the range from 1 to 8, particularly preferably 3.

17. Process according to claim 1, characterised in that at least one structural unit is an oligomer or polymer, preferably a macromonomer, where polyethers, polyolefins and polyacrylates are particularly preferred as macromonomers.

18. Use of nanoparticles according to claim 1 for the UV stabilisation of polymers.

19. UV-stabilised polymer composition essentially consisting of at least one polymer, characterised in that the polymer comprises nanoparticles according to claim 1.

20. Polymer according to claim 19, characterised in that the polymer is polycarbonate (PC), polyethylene terephthalate (PETP), polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA) or a copolymer having at least a fraction of one of the said polymers.

21. Process for the preparation of UV-stabilised polymer compositions, characterised in that the polymer material is mixed with nanoparticles according to claim 1, preferably in an extruder or compounder.

5. Process for the production of polymer-modified nanoparticles, characterised in that, in a step a), an inverse emulsion comprising one or more water-soluble precursors of the nanoparticles or a melt is prepared with the aid of a random copolymer of at least one monomer containing hydrophobic radicals and at least one monomer containing hydrophilic radicals, and, in a step b), particles are produced.

6. Process according to claim 5, characterised in that particles are produced in step b) by reaction of the precursors or by cooling of the melt.

7. Process according to claim 6, characterised in that the precursors are reacted with an acid, a base, a reducing agent or an oxidant.