Application of microcapsules as latent heat accumulators

• US 6,200,681 B1
• Filed: 05/11/2000
• Issued: 03/13/2001
• Est. Priority Date: 11/11/1997
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Jahns, Ekkehard, Reck, Bernd
• Primary Examiner(s): Acquah, Samuel A.
• Application Number:
  US09/554,076
• Time in Patent Office: 306 Days
• Field of Search: 428/402.21, 428/402.22, 428/40.24, 524/801, 524/802
• US Class Current: 428/402.24
• CPC Class Codes: B01J 13/14 Polymerisation; cross-linking
• CPC Class Codes: B01J 13/185 in an organic phase
• CPC Class Codes: C04B 16/08 porous, e.g. expanded polystyrene beads or microballoons
• CPC Class Codes: C04B 2103/0071 Phase-change materials, e.g. latent heat storage materials used in concrete compositions
• CPC Class Codes: C08K 9/10 Encapsulated ingredients
• CPC Class Codes: C08L 2207/53 Core-shell polymer
• CPC Class Codes: C09D 7/65 macromolecular C09D7/41-C09D7/48 take precedence
• CPC Class Codes: C09K 5/063 Materials absorbing or liberating heat during crystallisation; Heat storage materials
• CPC Class Codes: Y10T 428/2985 Solid-walled microcapsule from synthetic polymer
• CPC Class Codes: Y10T 428/2987 Addition polymer from unsaturated monomers only
• CPC Class Codes: Y10T 428/2989 Microcapsule with solid core [includes liposome]

Abstract

Used as latent heat storage media of microcapsules I comprising as core materials one or more lipophilic substances whose solid/liquid phase transition is within the range from −20 to 120° C. and as shell a polymer obtainable by free-radical polymerization of a monomer mixture comprising

from 30 to 100% by weight, based on the overall weight of the monomers, of one or more C₁-C₂₄-alkyl esters of acrylic and/or methacrylic acid (monomer I),

from 0 to 80% by weight, based on the overall weight of the monomers, of a bi- or polyfunctional monomer (monomers II) which is insoluble or of low solubility in water, and

from 0 to 40% by weight, based on the overall weight of the monomers, of other monomers (monomers III),

and also novel microcapsules Ia, spray-dried microcapsules Ia′, processes for their preparation and shaped articles and coating compositions comprising these microcapsules.

Claims

1. A method of using, as latent heat storage media, microcapsules I comprising as core materials one or more lipophilic substances whose solid/liquid phase transition is within the range from −

20 to 120°

C. and as shell a polymer obtainable by free-radical polymerization of a monomer mixture comprising

from 30 to 100% by weight, based on the overall weight of the monomers, of one or more C₁-C₂₄-alkyl esters of acrylic and/or methacrylic acid (monomer I), from 0 to 80% by weight, based on the overall weight of the monomers, of a bi- or polyfunctional monomer (monomer II) which is insoluble or of low solubility in water, and

from 0 to 40% by weight, based on the overall weight of the monomers, of other monomers (monomers III).

2. The method as claimed in claim 1 of using microcapsules I obtainable by heating an oil-in-water emulsion in which the monomers, a free-radical initiator and the lipophilic substance are present as disperse phase.

3. The method as claimed in claim 1 of using microcapsules I obtainable by continuous or stepwise heating.

4. The method as claimed in claim 1 of using microcapsules I obtainable by polymerizing the monomers, which together with the free-radical initiator, the lipophilic substance and an inorganic protective colloid are present as disperse phase of an oil-in-water emulsion.

5. The method as claimed in claim 1 of using microcapsules I as latent heat storage media in shaped mineral articles or coating compositions.

6. The method as claimed in claim 1 of using microcapsules I as latent heat storage media in polymeric shaped articles or coating compositions.

7. A shaped mineral article comprising microcapsules as set forth in claim 1 along with other customary additives to shaped mineral articles.

8. A mineral coating composition comprising microcapsules as set forth in claim 1 along with other customary additives to mineral coating compositions.

9. A polymeric shaded article comprising microcapsules as set forth in claim 1 along with other customary additives to polymeric shaped articles.

10. A polymeric coating composition comprising microcapsules as set forth in claim 1 along with other customary additives to polymeric coating compositions.

11. A process for preparing microcapsules Ia as set forth in claim 1 by converting from 30 to 100% by weight, based on the overall weight of the monomers, of one or more C₂-C₂₄-alkyl esters of acrylic and/or methacrylic acid (monomer I), from 0 to 80% by weight, based on the overall weight of the monomers, of a bi- or polyfunctional monomer (monomer II) which is insoluble or of low solubility in water, and

from 0 to 40% by weight, based on the overall weight of the monomers, of other monomers (monomers III),

a free-radical initiator and the lipophilic substance, together with an inorganic protective colloid, to an oil-in-water emulsion and polymerizing said emulsion by stepwise heating.

12. A process as claimed in claim 1, wherein the microcapsule dispersion is subsequently spray-dried.

13. A microcapsule Ia obtainable by a process as claimed in claim 11.