PROCESS FOR PREPARING AQUEOUS DISPERSIONS

• US 20110218291A1
• Filed: 05/18/2011
• Published: 09/08/2011
• Est. Priority Date: 12/19/2002
• Status: Abandoned Application

• Current Assignee: Evonik Rã¶Hm GmbH (Rag-Stiftung)
• Original Assignee: Evonik Rã¶Hm GmbH (Rag-Stiftung)
• Inventors: Schikowsky, Hartmut, Suefke, Thomas, Mueller, Reiner, SCHULTES, Klaus, Hoess, Werner
• Application Number:
  US13/110,074
• Publication Number:
  US 20110218291A1
• Time in Patent Office: Days
• US Class Current: 524/521
• CPC Class Codes: C08F 220/12 of monohydric alcohols or phenols
• CPC Class Codes: C08F 285/00 Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 33/10 Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: C08L 33/20 Homopolymers or copolymers of acrylonitrile C08L55/02 takes precedence
• CPC Class Codes: C08L 35/06 Copolymers with vinyl aromatic monomers
• 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: C08L 55/005 Homopolymers or copolymers obtained by polymerisation of macromolecular compounds terminated by a carbon-to-carbon double bond
• CPC Class Codes: C09D 133/10 Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer

Abstract

The present invention relates to a process for preparing aqueous dispersions. The invention also relates to the formation of core-shell particles in aqueous dispersions. The core-shell particles are useful as impact-modifiers for poly(meth)acrylate moulding compositions.

Claims

1. Core-shell particles obtained by a process comprising:

(1) preparing an aqueous polymer dispersion, and

(2) separating core-shell particles therefrom,

wherein (1) comprises;

a) preparing an initial charge of an aqueous emulsion of a long chain alkyl alcohol or a seed latex by polymerization of an alkyl (meth)acrylate in an aqueous medium comprising an emulsifier to a seed particle radius ranging from 3.0 to 20.0 nm

b) adding from 25.0 to 45.0 parts by weight of a first composition

comprising;

A) from 50.0 to 99.9 parts by weight of an alkyl (meth)acrylate having from 1 to 20 carbon atoms in the alkyl radical,

B) from 0.0 to 40.0 parts by weight of an alkyl acrylate having from 1 to 20 carbon atoms in the alkyl radical,

C) from 0.1 to 10.0 parts by weight of a crosslinking monomer, and

D) from 0.0 to 8.0 parts by weight of a styrenic monomer of the formula (I)

2. A moulding composition comprising, based in each case on its total weight, of

A) from 1.0 to 50.0% by weight of at least one core-shell particle according to claim 1,

B) from 1.0 to 99.0% by weight of at least one (meth)acrylic polymer,

C) from 0.0 to 45% by weight of at least one styrene-acrylonitrile polymer, and

D) from 0.0 to 10.0% by weight of other additives,

where the percentages by weight give 100.0% by weight in total.

3. The moulding composition according to claim 2, wherein the (meth)acrylic polymer encompasses, based in each case on its total weight, of

a) from 50.0 to 100.0% by weight of alkyl methacrylate repeat units having from 1 to 20 carbon atoms in the alkyl radical,

b) from 0.0 to 40.0% by weight of alkyl acrylate repeat units having from 1 to 20 carbon atoms in the alkyl radical and

c) from 0.0 to 8.0% by weight of styrenic repeat units of the formula (I),

where the percentages by weight give 100.0 W by weight in total.

4. The moulding composition according to claim 2, wherein the moulding composition comprises styrene/acrylonitrile copolymers, where the styrene/acrylonitrile copolymers are obtained by polymerizing any mixture which comprises

from 70 to 92 W by weight of styrene,

from 8 to 30% by weight of acrylonitrile, and

from 0 to 22% by weight of other comonomers, based in each case on the total weight of the monomers to be polymerized.

5. The moulding composition according to claim 2, wherein the moulding composition comprises, based on its total weight, from 0.1 to 10.0% by weight of another polymer whose weight-average molecular weight is higher by at least 10% than that of the (meth)acrylic polymer.

6. A moulding obtained from a moulding composition according to claim 2.

7. The moulding according to claim 6, wherein the moulding has a Vicat softening point ISO 306 (B50) of at least 85°

C., a notched impact strength NIS (Charpy179/1eA) to ISO 179 of at least 6.0 kJ/m² at 23°

C. and of at least 2.5 kJ/m² at −

10°

C., a modulus of elasticity to ISO 527-2 of at least 1500 Pa s, a haze to ASTM D 1003 (1997) of at most 2.5%, a transmittance (D) 65/10°

to DIN 5033/5036 of at least 88.5%.

8. The moulding according to claim 7, wherein the moulding has a Vicat softening point ISO 306 (B50) of at least 90°

C.

9. The moulding according to claim 8, wherein the moulding has a Vicat softening point ISO 306 (B50) of at least 93°

C.

10. The core-shell-particles according to claim 1, wherein a seed latex whose particle radius, measured by the Coulter method, is in the range from 5.0 to 20.0 nm is used to form the initial charge.

11. The core-shell-particles according to claim 1, wherein said initial charge is an aqueous emulsion of said long chain alkyl alcohol having from 12 to 20 carbon atoms in the alkyl radical.

12. The moulding composition according to claim 2, wherein the (meth)acrylic polymer has a number-average molar mass of from 1000 to 100,000,000 g/mol.

13. The moulding composition according to claim 12, wherein the number-average molar mass is from 10,000 to 1,000,000 g/mol.

14. The moulding composition according to claim 12, wherein the number-average molar mass is from 50,000 to 500,000 g/mol.

15. The moulding composition according to claim 3, wherein the (meth)acrylic polymer comprises from 85.0 to 100.0% by weight of alkyl methacrylate repeat units.

16. The moulding composition according to claim 5, wherein said weight-average molecular weight is higher by at least 50% than that of the (meth)acrylic polymer.

17. The moulding composition according to claim 5, wherein said weight-average molecular weight is higher by at least 100% than that of the (meth)acrylic polymer.

18. The moulding composition according to claim 2, wherein the (meth)acrylic polymer encompasses, based in each case on its total weight, of

a) from 85.0 to 99.5% by weight of alkyl methacrylate repeat units having from 1 to 4 carbon atoms in the alkyl radical,

b) from 0.1 to 15.0% by weight of alkyl acrylate repeat units having from 1 to 4 carbon atoms in the alkyl radical and

c) from 0.0 to 8.0% by weight of styrenic repeat units of the formula (I),

where the percentages by weight give 100.0% by weight in total.