Gas adsorption sheet and air-purifying filter

• US 20030207635A1
• Filed: 08/10/2001
• Published: 11/06/2003
• Est. Priority Date: 05/08/1998
• Status: Active Grant

• Current Assignee: Masayuki Imagawa, Shinichi Minemura
• Original Assignee: Masayuki Imagawa, Shinichi Minemura
• Inventors: Imagawa, Masayuki, Minemura, Shinichi
• Granted Patent: US 6,746,760 B2
• Time in Patent Office: Days
• US Class Current: 442/327
• CPC Class Codes: B01D 2239/0435 Electret apparatus incorporating such gas filtering material B01D46/0032
• CPC Class Codes: B01D 2239/045 Deodorising additives
• CPC Class Codes: B01D 2239/0613 Woven
• CPC Class Codes: B01D 2239/0618 Non-woven
• CPC Class Codes: B01D 2239/064 The fibres being mixed
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material apparatus incorporating such gas filtering material B01D2275/10
• CPC Class Codes: B01D 2239/086 Binders between particles or fibres
• CPC Class Codes: B01D 2239/10 Filtering material manufacturing
• CPC Class Codes: B01D 2239/1208 Porosity apparatus incorporating such gas filtering material B01D2275/30 - B01D2275/307
• CPC Class Codes: B01D 2239/1216 Pore size
• CPC Class Codes: B01D 2239/1225 Fibre length
• CPC Class Codes: B01D 2239/1241 Particle diameter
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: B01D 39/2017 the material being filamentary or fibrous
• CPC Class Codes: B01D 39/2055 Carbonaceous material solid sorbent compositions comprising free carbon B01J20/20
• CPC Class Codes: B01D 39/2058 the material being particulate
• CPC Class Codes: B01D 39/2062 Bonded, e.g. activated carbon blocks
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28011 : Other properties, e.g. density, crush strength
• CPC Class Codes: B01J 20/28028 : Particles immobilised within fibres or filaments
• CPC Class Codes: B01J 20/2803 : Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28033 : Membrane, sheet, cloth, pad, lamellar or mat
• CPC Class Codes: B01J 20/28057 : Surface area, e.g. B.E.T specific surface area
• CPC Class Codes: B01J 20/28069 : Pore volume, e.g. total pore volume, mesopore volume, micropore volume
• CPC Class Codes: D21H 13/08 : from regenerated cellulose
• CPC Class Codes: D21H 13/16 : Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters
• CPC Class Codes: D21H 13/24 : Polyesters
• CPC Class Codes: D21H 15/10 : Composite fibres
• CPC Class Codes: D21H 17/67 : Water-insoluble compounds, e.g. fillers, pigments
• CPC Class Codes: D21H 21/22 : Agents rendering paper porous, absorbent or bulky
• CPC Class Codes: D21H 21/52 : Additives of definite length or shape
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/25 : Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 442/10 : Scrim [e.g., open net or mesh, gauze, loose or open weave or knit, etc.]
• CPC Class Codes: Y10T 442/30 : Woven fabric [i.e., woven strand or strip material]
• CPC Class Codes: Y10T 442/60 : Nonwoven fabric [i.e., nonwoven strand or fiber material]
• CPC Class Codes: Y10T 442/614 : Strand or fiber material specified as having microdimensions [i.e., microfiber]
• CPC Class Codes: Y10T 442/615 : Strand or fiber material is blended with another chemically different microfiber in the same layer
• CPC Class Codes: Y10T 442/619 : Including other strand or fiber material in the same layer not specified as having microdimensions
• CPC Class Codes: Y10T 442/621 : Including other strand or fiber material in a different layer not specified as having microdimensions
• CPC Class Codes: Y10T 442/625 : Autogenously bonded
• CPC Class Codes: Y10T 442/659 : Including an additional nonwoven fabric
• CPC Class Codes: Y10T 442/668 : Separate nonwoven fabric layers comprise chemically different strand or fiber material
• CPC Class Codes: Y10T 442/674 : Nonwoven fabric with a preformed polymeric film or sheet
• CPC Class Codes: Y10T 442/696 : Including strand or fiber material which is stated to have specific attributes [e.g., heat or fire resistance, chemical or solvent resistance, high absorption for aqueous compositions, water solubility, heat shrinkability, etc.]
• CPC Class Codes: Y10T 442/697 : Containing at least two chemically different strand or fiber materials
• CPC Class Codes: Y10T 442/699 : Including particulate material other than strand or fiber material

Abstract

The gas adsorption sheet of the present invention has a granular activated carbon-containing sheet comprising a granular activated carbon having an average particle diameter of 60 to 600 μm, a supporting fiber for fixing the granular activated carbon in contact with it, and an adhesive fiber which mainly contributes to shape retention. An air-purifying filter of the present invention is obtained by forming the gas adsorption sheet into a shape of pleats or wave. A method for producing a gas adsorption sheet of the present invention comprises a step of forming a granular activated carbon-containing sheet by using an aqueous slurry containing a granular activated carbon, a supporting fiber and a water-swelling adhesive fiber.

Claims

1. A gas adsorption sheet having a granular activated carbon-containing sheet, said granular activated carbon-containing sheet comprising:

a granular activated carbon having an average particle diameter of 60 to 600 μ

m,

a supporting fiber for fixing the granular activated carbon in contact with it, and

an adhesive fiber which mainly contributes to shape retention.

2. The gas adsorption sheet according to claim 1, wherein the granular activated carbon-containing sheet comprises a surface layer and a back layer formed on the back of the surface layer, the surface layer containing less granular activated carbon than the back layer.

3. The gas adsorption sheet according to claim 2, wherein the granular activated carbon-containing sheet is integrally formed by wet bonding using a water-swelling fiber as the adhesive fiber.

4. The gas adsorption sheet according to claim 1, wherein an outer surface area of the supporting fiber is not more than 1 m²/g, a fiber length thereof is from 3 to 20 mm and a density thereof is from 0.8 to 1.7 g/cc.

5. The gas adsorption sheet according to claim 1, wherein the granular activated carbon-containing sheet contains the granular activated carbon in an amount of 30 to 80% by weight based on the total weight thereof.

6. The gas adsorption sheet according to claim 1, wherein the granular activated carbon-containing sheet is provided with small pores capable of substantially permeating an air in a thickness direction.

7. The gas adsorption sheet according to claim 6, wherein an average open area per one pore of the small pores is from 0.5 to 3 mm².

8. The gas adsorption sheet according to claim 6, wherein the number of the small pores is from 1 to 20 per 1 cm² of the granular activated carbon-containing sheet.

9. The gas adsorption sheet according to claim 6, wherein a porosity of the small pores is from 3 to 10%.

10. The gas adsorption sheet according to claim 1, which further comprises an air-permeable sheet in addition to the granular activated carbon-containing sheet.

11. The gas adsorption sheet according to claim 10, wherein the air-permeable sheet is laminated on the back layer of the granular activated carbon-containing sheet.

12. The gas adsorption sheet according to claim 10, wherein the air-permeable sheet comprises a non-woven fabric made of a film split type electret fiber as a main component.

13. The gas adsorption sheet according to claim 12, wherein the air-permeable sheet is further provided with a cover sheet in the form of a non-woven fabric, woven fabric or net.

14. The gas adsorption sheet according to claim 12, wherein a packing density of the air-permeable sheet is from 0.01 to 0.20 g/cc.

15. An air-purifying filter obtained by forming a gas adsorption sheet having a granular activated carbon-containing sheet into a shape of pleats or wave, said granular activated carbon-containing sheet comprising:

a granular activated carbon having an average particle diameter of 60 to 600 μ

m,

a supporting fiber for fixing the granular activated carbon in contact with it, and

an adhesive fiber which mainly contributes to shape retention.

19. The air-purifying filter according to claim 15, wherein a thickness of the filter formed is from 10 to 400 mm and a distance between crests is from 2 to 30 mm.

16. An air-purifying filter obtained by forming a gas adsorption sheet having a granular activated carbon-containing sheet into a shape of pleats or wave, said granular activated carbon-containing sheet having small pores capable of substantially permeating an air in a thickness direction and comprising:

a granular activated carbon having an average particle diameter of 60 to 600 μ

m,

a supporting fiber for fixing the granular activated carbon in contact with it, and

an adhesive fiber which mainly contributes to shape retention.

17. An air-purifying filter obtained by forming a gas adsorption sheet having a granular activated carbon-containing sheet and an air-permeable sheet into a shape of pleats or wave, said granular activated carbon-containing sheet comprising:

a granular activated carbon having an average particle diameter of 60 to 600 μ

m,

a supporting fiber for fixing the granular activated carbon in contact with it, and

an adhesive fiber which mainly contributes to shape retention.

18. An air-purifying filter obtained by forming a gas adsorption sheet having a granular activated carbon-containing sheet and an air-permeable sheet into a shape of pleats or wave, said granular activated carbon-containing sheet comprising:

a granular activated carbon having an average particle diameter of 60 to 600 μ

m,

a supporting fiber for fixing the granular activated carbon in contact with it, and

an adhesive fiber which mainly contributes to shape retention,

and said air-permeable sheet being further provided with a cover sheet in the form of a non-woven fabric, woven fabric or net.

20. A method for producing a gas adsorption sheet, which comprises a step of forming a granular activated carbon-containing sheet, said step of forming a granular activated carbon-containing sheet comprising the steps of:

preparing an aqueous slurry containing a granular activated carbon having an average particle diameter of 60 to 600 μ

m, a supporting fiber and a water-swelling adhesive fiber,

spreading the aqueous slurry in a sheet-like form, and

mechanically dewatering and drying the aqueous slurry spread.