# US 8,540,957 B2 · Method for preparing microtubular halloysite nanopowders

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- Number: US 8,540,957 B2
- Document ID: US8540957B2
- Status: Granted
- Kind: B2
- Application number: 12/954,878
- Filed: 2010-11-28
- Published: 2012-05-03
- Granted: 2013-09-24
- Earliest claimed: 2010-10-28
- Assignees: Korea Institute of Geoscience and Mineral Resources
- Applicants: Yong Jae Suh; Young Mi Heo; Dae Sup Kil; Sung Wook Cho
- Inventors: Yong Jae Suh; Young Mi Heo; Dae Sup Kil; Sung Wook Cho
- Web page: https://patentgrep.com/patent/US8540957B2

## CPC

- C01B 33/26: Aluminium-containing silicates {, i.e. silico-aluminates}
- A61K 8/0245: {Specific shapes or structures not provided for by any of the groups of A61K8/0241}
- A61K 8/26: Aluminium; Compounds thereof
- A61Q 19/00: Preparations for care of the skin
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- A61K 2800/10: General cosmetic use
- A61K 2800/413: Nanosized, i.e. having sizes below 100 nm
- C01P 2004/13: Nanotubes
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61Q: SPECIFIC USE OF COSMETICS OR SIMILAR TOILETRY PREPARATIONS
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

The present invention provides a method for preparing microtubular halloysite nanopowders by cutting halloysite nanotubes at a high pressure, microtubular halloysite nanopowders prepared by the method, and a cosmetic composition comprising the microtubular halloysite nanopowders. According to the method of the present invention, it is possible to prepare the halloysite nanopowders with a tubular shape using natural halloysite and effectively select a halloysite nanopowder having a desired shape. The microtubular halloysite nanopowders can be used in many industrial fields and used as a container or a carrier for nanoparticles or organic materials such as drugs, air fresheners, cosmetics, agricultural chemical materials, etc.

## Claims

### Claim 1

A method for preparing a microtubular halloysite nanopowder, comprising cutting a halloysite nanotube at 15,000 to 25,000 psi pressure.

### Claim 2 (depends on 1)

The method of claim 1, wherein the cutting of the halloysite nanotube comprises continuously grinding the halloysite nanotube 3 to 9 times.

### Claim 3 (depends on 1)

The method of claim 1, wherein the microtubular halloysite nanopowder has a length of 1 to 10 μm with a tubular shape.

### Claim 4 (depends on 1)

The method of claim 1, wherein the microtubular halloysite nanopowder has a length of 1 to 5 μm with a tubular shape.

### Claim 5 (depends on 1)

The method of claim 1, wherein the halloysite nanotube cut at a high pressure is in the form of a 3 to 10 wt % colloidal solution.

### Claim 6 (depends on 1)

The method of claim 1, further comprising selecting a halloysite nanopowder having a desired shape from the cut halloysite nanotubes using a continuous centrifuge.

### Claim 7 (depends on 6)

The method of claim 6, wherein the microtubular halloysite nanopowder has a length of 1 to 5 μm with a tubular shape.

### Claim 8 (depends on 6)

The method of claim 6, wherein the selecting of the halloysite nanopowder comprises lining a centrifuge tube with a PTFE (Polytetrafluoroethylene) sheet and operating the centrifuge.