Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B1/84—Sound-absorbing elements
  • E04B1/86—Sound-absorbing elements slab-shaped
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/162—Selection of materials
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
  • E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
  • E04C2/12—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of solid wood
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
  • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
  • E04C2/44—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the purpose
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B2001/742—Use of special materials; Materials having special structures or shape
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B1/84—Sound-absorbing elements
  • E04B2001/8457—Solid slabs or blocks

Definitions

• the present invention relates to a method of improving the sound-absorbing performance of wood as a sound-absorbing material , and more particularly to a method of improving the abi l ity of wood to absorb sound waves incident in the . fiber direction of the wood in a given frequency range by delignifying it .
• An object of the present invention is to provide a sound-absorbing board having sound-absorbing propert ies superior to that of unmodified wood by chemical ly treating wood.
• glass fiber , rock wool , gypsum board and the like which are used as internal or external sound-absorbing materials, are frequent ly used as bui lding materials, because they have excel lent sound-absorbing capacity and insulation properties .
• they wi l l have a harmful effect on human health due to dust , etc. , so that their use has gradual ly been restricted.
• these materials have low intrinsic strength, and so require a supporting frame.
• Wood with the potential to replace non-eco-friendly materials, is a recyclable natural material and has a beautiful appearance and good processabi l ity, as wel l as excel lent strength compared to other materials.
• wood resources in Korea mainly consist of smal l-diameter logs, curved logs and the l ike, and thus, there is a need to maximize the uti l ity of the smal l-diameter logs or curved logs, having low added value.
• the present inventor has del ignified wood materials, using smal l-diameter logs or curved , logs, by chem.i.ca .
• Wood is a sound reflective material having a sound absorpt ion of about 5% in a frequency range that human beings mainly use during their l i fe.
• 99-38842 (entitled “a sound-absorbing wood material and a preparation method thereof") fi led by the appl icant discloses a wood board having improved sound-absorbing performance and low density and, at the same time, requisite strength, which is prepared by a method comprising the steps of: adding a synthetic resin adhesive to wood particles in an amount of about 5-30% by weight and stirring the mixture; forming the stirred mixture into a mat ; placing the mat into a mold having a plural ity of discharge holes form in the circumferential surface thereof ; interposing the mold between upper and lower cowls each having a plurality of core pins, which have different diameters and are arranged on the same axis", and pressing the upper and lower cowls, in which the pressing step is performed at a temperature of about 140-240 °C and a pressure of about 20-40 kg/cm 2 for at least 5 minutes.
• Korean Patent Laid-Open Publ ication No. 2003-30645 discloses a wood floor structure comprising: a sound-absorbing elastic material having perforated adhesive holes to be fi lled with an elasticity-reinforcing adhesive; and a wood floor panel placed on the sound-absorbing > elastic material after being fi lled with the elasticity-reinforcing adhesive.
• the above-published wood materials comprise, in addition to wood, a separate material for improving sound-absorbing performance
• these materials are difficult to realize and do not meet the eco-friendly trend.
• the present inventor developed a method capable of improving the sound-absorbing performance of wood using wood anatomical approach and based on his through study of wood structure, thereby completing the present invent ion.
• the sound-absorbing performance wi l l now be described in order to ful ly understand the present invention.
• the absorption of sound is a process for removing or reducing the energy of sound.
• Sound absorpt ion is achieved by contact with a sound-absorbing material having many pores, or by the vibration of a thin plate disposed on the wall surface with an air layer interposed therebetween, or by a sound- absorbing device including a single resonator .
• the absorbance of sound by the porous material varies depending on the thickness of the porous material , it shows an excel lent effect in a wide frequency range, but the porous material needs structural support .
• the plate vibration shows good sound absorbance only in low frequency range.
• the absorbance of sound by the single resonator shows high sound-absorbing effects only in a narrow frequency range.
• glass wool or rock wool is frequently used in bui ldings, owing to the advantages of good insulation properties in addition to sound- absorbing effects, but when exposed to air, during use, it can have a harmful- effect on the human health due to dust . Also, this material has poor strength, and thus requires a supporting frame. Accordingly, the present inventor believes that there is a need to develop new materials, which have suitable levels of sound-absorbing and insulation properties and, at the same time, are not harmful to the humans, one of these materials being a wood material .
• the main objective of the present invention is to provide an eco-friendly, sound-absorbing material .
• Another objective is to provide a method for improving the sound-absorbing properties of wood by removing substances from wood cell wal ls through a wood anatomical approach.
• the present invention provides a method for improving the sound-absorbing performance of wood, comprising the steps of : processing normal wood into a wood disc; removing l ignin from the wood disc! and drying the del igni fied wood disc under reduced pressure.
• the kind of tree from which the wood used in the present invent ion is to be obtained is not specifical ly l imited.
• Wood mainly consists of cel lulose, hemicel lulose and lignin, in which the lignin to be removed according to the present invention is a polymer having a molecular weight of more than 50,000 and including a phenylpropane-type carbon framework deposited between the cellulose microfibrillar structures of wood. Lignin accounts for 20-30% of the dry weight of wood.
• the del ignification step can be performed using a known method, such as the chlorine-monoethanolamine method, comprising chlorinating the wood discs, which renders wood discs brighter , or the peracetic acid method. It is preferable in the present invention to use the sodium chlorite method for oxidizing, degrading and dissolving out the lignin.
• the delignified wood discs are dried under reduced pressure conditions (pressure: 70-90 cmHg; and temperature: 30- 50 "C) to a water content of 10-15%, which results in fine cracks on the surface of the wood discs.
• pressure 70-90 cmHg
• temperature 30- 50 "C
• the present invention is described with respect to the improvement of sound-absorbing performance only for the wood discs, the inventive idea of improving sound absorbance by increasing the wood pores can likewise be applied to plywood, particle board and fiber board.
• the present invention wi l l be described in detai l with examples, but it is to be noted that these examples are for illustrative purpose only and are not construed to l imit the scope of the present invention.
• a sound reflective wood material having a sound absorbance of about 5% can be significantly improved with respect to sound-absorbing performance in a frequency of 2 KHz-4 KHz, in which the human hearing sense is general ly most sensitive.
• rock wool , glass fiber and . the l ike which have been, used as sound-absorbing internal materials , can be substituted with inexpensive wood.
• the sound-absorbing wood material according to the present invent ion is eco-friendly, and so can be used without fear of health hazard or damage to environment .
• the inventive material is recyclable so that it is superior to other materials in the efficiency of resource uti l ization, whereby it can contribute to the efficient uti l izat ion of resources and to an increase in the value of wood products .
• FIG. 1 is a photograph showing the result of visual observation for a wood disc treated with the inventive method of improving sound-absorbing properties.
• FIG. 2 is an electron micrograph showing a portion of the cross section of the wood disc shown in FIG. 1.
• FIG. 3 shows the sound-absorbing properties of a wood disc treated with the inventive method and an untreated wood disc.
• specimen 1 is a result for the wood disc treated with the inventive method
• specimen 2 is a result for the untreated wood disc .
• Larch wood was processed in the transverse direction (to a 100-mm diameter for a middle and low frequency specimen and a 29.9-mm diameter for a high frequency range specimen, and a 30-mm thickness) , to prepare wood discs .
• Each of the wood discs was degreased with a mixture of alcohol and benzene and kept in a water bath with 1.21 of water containing 8 g of sodium chlorite and 1.6 ml of glacial acetic acid at 80 ° C for 120 hours.
• Each of the del ignified wood discs was dried to a moisture content of 12% in a vacuum dryer at a pressure of 76 cmHg and a temperature of 40 °C .
• FIG. 1 is a photograph showing the result of visual observat ion for a wood disc treated with the invent ive method for improving sound-absorbing propert ies
• FIG. 2 is an electron micrograph showing a port ion of the cross section of the wood disc shown in FIG. 1.
• the wood cel l wal ls which has a high content of lignin, showing an elastic behavior in wood, was removed, the wood has an increased porosity leading to a reduced reflectivity to sound waves, thus showing improved sound-absorbing properties.
• FIG. 3 shows the sound-absorbing properties of a wood disc treated with the inventive method and an untreated wood disc.
• the wood disc according to the present invention showed improved sound-absorbing performance over the entire measured frequency range, compared to the untreated wood disc.
• the inventive wood disc showed a 30% higher sound absorbance than that of the untreated wood disc.
• the inventive wood disc was almost twice as high in sound absorbance as the untreated disc.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Architecture (AREA)
• Acoustics & Sound (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Electromagnetism (AREA)
• Multimedia (AREA)
• Chemical And Physical Treatments For Wood And The Like (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=36740701

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (1)

Citations (6)

Family Cites Families (3)

• 2004
  • 2004-10-20 KR KR1020040083840A patent/KR100692509B1/ko not_active IP Right Cessation
• 2005
  • 2005-10-08 EP EP05856497A patent/EP1809825B1/en not_active Expired - Fee Related
  • 2005-10-08 WO PCT/KR2005/003350 patent/WO2006080731A1/en active Application Filing
  • 2005-10-08 DE DE602005015744T patent/DE602005015744D1/de not_active Expired - Fee Related

Patent Citations (6)

Non-Patent Citations (1)

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