WO2005110744A1

WO2005110744A1 - Manufacturing method of functional charcoal board laminate

Info

Publication number: WO2005110744A1
Application number: PCT/KR2005/001242
Authority: WO
Inventors: Hwa-Hyoung Lee; Youn-Mean Cho; Han-Sang Park
Original assignee: The Industry & Academic Cooperation In Chungnam National University(Iac)
Priority date: 2004-04-29
Filing date: 2005-04-28
Publication date: 2005-11-24
Also published as: JP2007537057A; JP4520501B2

Abstract

Disclosed herein is a method for preparing a functional charcoal board laminate comprising a thin paper with a printed pattern or a non-woven fabric of chemical fibers on a side of a charcoal board which has superior appearance while maintaining properties of charcoal such as dehumidification, moisturization, ventilation, adsorption and the like, thereby providing air purification effect by adsorbing offensive odor and harmful gas, emitting far-infrared rays and anions, preventing noise, blocking electromagnetic and harmful waves, promoting blood circulation and metabolism and stabilizing mental and physical conditions.

Description

MANUFACTURING METHOD OF FUNCTIONAL CHARCOAL BOARD LAMINATE

Technical Field The present invention relates to a method for preparing a functional charcoal board laminate by adhering a print thin paper or a non- woven fabric of chemical fibers on a side of a charcoal board maintaining properties of charcoal to provide aesthetic effect without deterioration of charcoal functions.

Background Art In general, charcoal has properties of moisturization, ventilation, adsorption, heat storage and can purify air by adsorbing offensive odor and toxic gases, emit far-infrared rays and anions, prevent noise and shielding electromagnetic waves and harmful waves. Also, it is used as a material to promote blood circulation and metabolism and to stabilize mental and physical conditions. Therefore, recently, many households use charcoal by placing several lumps of charcoal contained in a certain container next to computers and televisions or in wardrobes and at a corner of a living room, which is not favorable in the appearance. A method for filling in the ground for building with charcoal has been used in ancient toms since 2000 years ago and increases electric potential of residential environment, releases anions and makes optimum environment for human bodies and construction materials by anti-oxidation, air purification, gas adsorption, humidity adjustment, emission of far-infrared rays and the like. Recently, in application to the interior of buildings, charcoal is put in a bag of non- woven fabric to be placed under a floor of a living room or is contained in a sheet to be inserted in walls to induce pleasant and fresh conditions. The method for preparing a charcoal board by carbonization, that is, the wood ceramic method (Japanese Patent Laid-Open Publication No. Hei 4-164806) was developed to solve the problems generating upon carbonization of general wood charcoal, such as splitting and twisting. However, this method had disadvantages in that it comprises 4 steps, making it complicated and a large amount of phenol resins are consumed (60 to 100% of fiber board). Meanwhile, Korean Patent Registration No. 10-0480539, issued to the present applicant disclosed a method for preparing a clay-wood ceramic using clay as porous carbonaceous substance, thereby reducing the process into 2 steps. However, both the wood ceramic and the clay-wood ceramic should be carbonized into a plate of a large area to be used as construction materials and an apparatus for continuously carrying out such carbonization of a large area for a long period of time requires enormous equipment investment and accuracy. Therefore, Korean Patent Application No. 10-2005-0008255 disclosed a method for preparing a composite of a functional board and a charcoal board by introducing porous carbonaceous materials as human body-friendly materials for residential environments while properly processing particle sizes of charcoal or carbide chips prepared using a conventional carburizing furnace and a continuous carburizing furnace, or commercially available activated charcoal and preventing deterioration in functions of charcoal due to use of an adhesive, in which the board composite is free from VOC problems caused by formalin and volatile solvents, is readily formed and hot pressed and has sufficient strength and surface properties to be used as construction elements. However, it did not include surface decoration and laminate for various constructions and manufacture, and particularly, did not mention a laminate excellent in adsorption of volatile organic compounds and emission of far-infrared rays. In some advanced countries including Japan, due to sick house related problems, the revised Building Standards Acts has been applied since July 2003. As a result, formalin free interior finishing materials of E0 type having formalin release of nearly 0 are now used to solve the VOC problems. The housing industry and the wood industry make an effort to promptly cope with environmental response. According to the Ministry of Environment of Korea in 2000, the VOC level showing the indoor environment pollution was 600 ppb, more than 8 times of the standard value, in buildings which had been 3 months or more old from construction, due to wall

paper (3833 /tg/π h), various paints, formalin based adhesives used in wooden materials and the

like. Therefore, if a construction element using charcoal may realize the properties of charcoal such as air purification, emission of far-infrared rays and anions, sound proof, shielding of electromagnetic wave and harmful waves through purification of volatile organic compounds, removal of offensive odor, and moisturization, ventilation, adsorption and heat storage, it would be a superior human body-friendly material. However, in the construction industry largely using concrete and cement, since the charcoal products usually shows the surface color of black, they have a limit in application as residential environment elements and thus, it is desired to have a composite material to supplement the decorative aspect. So far, the present applicant has been developed composites of charcoal board overlaid with a thin veneer or combined with a perforated wood fiber tile to have good surface properties for use as interior finishing materials. However, there is a demand to have a method for realizing functions of the charcoal board while providing good surface properties by overlaying a thin paper with a printed pattern or a non-woven fabric of chemical fibers to satisfy various consumer requirements.

Disclosure of Invention Therefore, it is an object of the present invention to provide a method for preparing a functional charcoal board laminate which can be used as an interior finishing material for construction while maintaining properties and functions of charcoal such as adsorption of a charcoal board by applying a thin paper with a wooden pattern printed to show an elegant appearance or a non-woven fabric of chemical fibers using an water based vinyl adhesive, whereby the produced laminate has excellent decorativeness and processability, and easiness in construction as well as properties of the charcoal board per se. It is another object of the present invention to provide a method for preparing a functional charcoal board laminate having an elegant appearance while maintaining functions of far-infrared emission and gas adsorption by using a water based adhesive without releasing toxic materials and carrying out the process under a specific condition. In order to achieve the above objects, according to the present invention, there is provided a method for preparing a functional charcoal board laminate by applying a thin paper with a printed pattern or a non-woven fabric of chemical fibers on a side of a charcoal board using a water based adhesive under a specific condition so that the laminate has an elegant appearance while maintaining properties of the charcoal board. The charcoal board, which can be used according to the present invention, is prepared by the following method. The charcoal board may be prepared by two types of methods. Firstly, charcoal particles having a particle size of 40 to 60 mesh were mixed with an adhesive mixture of polyvinyl acetate resin emulsion and an isocyanate resin. For example, the adhesive mixture comprises 15 % by weight of polyvinyl acetate resin emulsion and 5 % by weight of an isocyanate resin. The charcoal board is prepared by subjecting the adhesive and the charcoal particles to the hot press process. Preferably, the hot press process is carried out by 3 steps with different hot press conditions, which comprises a primary press step at a pressure, a secondary press step at a pressure which is lower than the pressure used in the primary press step and a tertiary press step at a pressure which is higher than the pressure used in the secondary press step. According to the present invention, the press steps are carried out at a pressure in the range of 5

to 40kgf/cnf in order to prevent destruction of structure of charcoal particles. For example, the

primary press step is carried out at a pressure of 30kgf/cπf for 1 minute, the secondary press step is carried out at a pressure of lOkgf/cn for 1 minute and 30 seconds and the tertiary press step is

carried out at a pressure of 30kgf/cπ for 6 minutes. Here, the press temperature is 150 to

200 °C . The isocyanate resin, which can be used according to the present invention, is not particularly limited and commonly used isocyanate resins may be used. Alternatively, a mixture of charcoal particles comprising 7 % by weight of charcoal particles having a particle size of 6 to 12 mesh, 14 % by weight of charcoal particles having a particle size of 12 to 18 mesh, 43% by weight of charcoal particles having a particle size of 18 to 40 mesh, 23% by weight of charcoal particles having a particle size of 40 to 60 mesh, 9% by weight of charcoal particles having a particle size of 60 to 100 mesh and 4% by weight of charcoal particle having a particle size of 100 mesh or less is mixed with an adhesive comprising 15 % by weight of polyvinyl acetate resin emulsion and 5 % by weight of an isocyanate resin.

The mixture is subjected to a primary hot press step at a pressure of 30kgf/cm² for 1 minute, a

secondary hot press step at a pressure of lOkgf/cnf for 1 minute and 30 seconds and a tertiary hot

press step at a pressure of 30kgf/cm² for 6 minutes. Here, the hot press temperature is 150 to

200 ^°C . The charcoal board thus obtained has preferably a strength of 4.0N/mnf or more and a

final mat moisture content of 26 to 50%. According to the present invention, the thin paper with a print has preferably a basis

weight of 15 to 35 g/n and a thickness of 0.02 to 0.08 mm. If the paper is out of the foregoing

ranges, gas adsorption property or strength may be deteriorated. According to the present invention, the non-woven fabric of chemical fibers has

preferably a basis weight of 20 to 40g/m², a thickness of 0.05 to 0.30 mm, and a porosity of 30 to

50% for optimum far-infrared ray emission and gas adsorption properties. More preferably, a non- woven fabric of polypropylene may be used to increase durability of the board, since it has a high strength. The adhesive, which is used to adhere the charcoal board and the thin paper with a printed pattern or the non-woven fabric of chemical fibers according to present invention, is preferably a water-based vinyl adhesive. The water-based vinyl adhesive is environment- friendly and does not release VOC (Volatile Organic Chemicals), which is harmful to human bodies. Thus, the charcoal board laminate can maintain the intrinsic properties of charcoal and show effects of gas adsorption and far-infrared ray emission, which is equal or superior to those of the charcoal board. According to the present invention, polyvinyl acetate resin emulsion (non- volatile: 42%) shows excellent properties.

The adhesive is preferably applied in an amount of 100 to 300g/m\ The adhesive is

applied on a side of the charcoal board and the thin paper with a print or the non- woven fabric of chemical fibers is adhered thereto at a heating temperature of 100 to 150^°C, and a pressure of 5

to 15 kg/cm², for a hot press time of 1 to 5 minutes. The foregoing conditions affect adhesion

efficiency, moisture evaporation and charcoal density, improving gas adsorption and far-infrared ray emission properties of the final product. Thus, under the foregoing conditions, the moisture evaporation and the properties of the adhesive work together to accomplish sufficient gas adsorption and far-infrared ray emission effects claimed by the present invention. The present invention can provide a charcoal board having superior appearance while maintaining properties of charcoal such as dehumidification, moisturization, ventilation, adsorption and the like, thereby providing air purification effect by adsorbing offensive odor and harmful gas, emitting far-infrared rays and anions, preventing noise, blocking electromagnetic and harmful waves, promoting blood circulation and metabolism and stabilizing mental and physical conditions. According to the present invention, it is possible to prepare a charcoal board laminate by laminating a print thin paper or a non-woven fabric of chemical fibers on the surface of a charcoal board to provide superior appearance, excellent gas adsorption, far-infrared ray emission and electromagnetic shielding effect. The charcoal board laminate can be used as excellent human body-friendly materials of interior finishing elements in residential environments.

Brief Description of Drawings Further objects and advantages of the present invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings in which: Fig. 1 shows a photograph of the charcoal board laminate having a print thin paper attached thereon according to the present invention; Fig. 2 is a photograph of the charcoal board laminate having a non- woven fabric attached thereon according to the present invention; and Fig. 3 is a photograph of the charcoal board formed of fine charcoal according to the present invention.

Best Mode for Carrying Out the Invention

Now, the present invention will be explained through the following examples. However, it should be understood that the present invention is not limited thereto.

Example 1 Preparation of charcoal board Fine charcoal of Oriental oak (Quercus variabilis BL) from Wonju-shi, Kangwon-do (Korea) was used to prepare a charcoal board of porous carbonaceous material. A mixture of fine charcoal particles comprising 7 % by weight of charcoal particles having a particle size of 6 to 12 mesh, 14 % by weight of charcoal particles having a particle size of 12 to 18 mesh, 43% by weight of charcoal particles having a particle size of 18 to 40 mesh, 23% by weight of charcoal particles having a particle size of 40 to 60 mesh, 9% by weight of charcoal particles having a particle size of 60 to 100 mesh and 4% by weight of charcoal particle having a particle size of 100 mesh or less was mixed with an adhesive comprising 15 % by weight of polyvinyl acetate resin emulsion (non- volatile: 42%) and 5 % by weight of an isocyanate resin. The mixture was subjected to a primary hot press step at a pressure of 30kgf/

cm² for 1 minute, a secondary hot press step at a pressure of 10kgf/cm² for 1 minute and 30

seconds and a tertiary hot press step at a pressure of 30kgf/cn for 6 minutes to form a mixed

charcoal board. Here, the hot press temperature was 170 ^°C and the mat moisture content before the hot press process was 36%. Preparation of charcoal board laminate with print thin paper To the charcoal board, a thin paper with a printed pattern was attached. The pattern thin

paper had a basis weight of 35 g/π and a thickness of 0.04mm. The adhesive was polyvinyl

acetate resin emulsion (non- volatile: 42%) and was applied in an amount of 160g/rr . The

laminate of the charcoal board and the thin paper was prepared by the hot-press process at a

heating temperature of 130 ^°C and a pressure of 10 kg/cm² for 2 minutes. The product is shown

in Fig. 1.

Example 2 Preparation of charcoal board laminate with non- woven fabric of chemical fibers Following the method of Example 1, a mixed charcoal board (fine charcoal board) was prepared and a polypropylene non- woven fabric was adhered thereto. The non- woven fabric had a basis weight of 30 g/m², a thickness of 0.12mm and a porosity of 39.3%. The adhesive was polyvinyl acetate resin emulsion (non- volatile: 42%) and was applied in an amount of 80g/ m². The laminate was prepared by the hot-press process at a heating temperature of 100^°C and a pressure of 10 kg/cπf for 2 minutes. The product is shown in Fig. 2.

Comparative Examples Comparative Example 1 used charcoal (fine charcoal) of the same composition as that of Example 1 according to the present invention. Comparative Example 2 was the charcoal board prepared by the same methods as those of Example 1 and Example 2 without having a print thin paper or non- woven fabric laminated thereon.

Experimental Example 1 The charcoal boards of Examples 1 and 2 and Comparative Examples 1 and 2 were placed in a test chamber to examine adsorption of ethylene gas. The result is shown in Table 1.

Table 1

*2. The charcoal board (dimension: 5cm X 5cm X 0.35cm) was loaded in the test chamber so that the gas was adsorbed only onto the surface. Change in concentration of remaining ethylene gas in the chamber according to time, in ppm. The lower number means that the more gas was adsorbed. ³: Charcoal board prepared according to Example 1

As seen from Table 1, the boards made of charcoal showed higher gas adsorption than charcoal itself. It was believed that this was because fine charcoal is pulverized properly into fine particles. Also, it was noted that the fine charcoal board overlaid with a pattern-printed thin paper showed higher gas adsorption than fine charcoal itself but showed little difference from the fine charcoal board without an overlaid thin paper.

Experimental Example 2 The charcoal boards of Examples 1 and 2 and Comparative Example 2 were used to examine physical and mechanical properties following the adhesion and the result is shown in Table 2. In Table 2, the charcoal boards and charcoal board laminates have a thickness of 3.5mm.

Table 2

As can be seen from Table 2, the fine charcoal board overlaid with a print thin paper showed a strength higher than that of fine charcoal board itself. Therefore, as shown in Example 1 and Example 2, it was proved that if the interior of a room was finished with a fine charcoal board overlaid with a non- woven fabric, the functions of charcoal could be sufficiently provided along with decorative effects, as compared to putting fine charcoal in the room.

Experimental Example 3 The charcoal boards of Examples 1 and 2 and Comparative Example 2 were used to examine far-infrared ray emission following the adhesion and the result is shown in Table 3.

Table 3

As shown in Table 3, the laminate according to the present invention showed inferior far- infrared ray emission to the fine charcoal board. However, the laminate showed 90% or more of emission at room temperature, indicating that it was excellent far-infrared ray emitting substance.

Experimental Example 4 The charcoal boards of Example 1 and Comparative Example 2 were used to examine electromagnetic shielding effect by plane wave of the plane material following the adhesion according to the following conditions and the result is shown in Table 4. 1) Test conditions: 24± 2 ^°C , 43± 5% R.H 2) Test method: ASTM D4935-89

Table 4

As shown in Table 4, the electromagnetic shielding effect could be accomplished whether a pattern print thin paper or a non-woven fabric was attached. In practice, mobile phones have a function to check them ringing when they were placed in a box made of the charcoal board. Therefore, it was proved that the effects when the interior of a room was finished with a charcoal board overlaid with a print thin paper were greater than when fine charcoal was placed in the room and the laminate according to present invention could provide sufficiently functions of charcoal along with decorativeness. Industrial Applicability As described above, the present invention can provide a charcoal board having superior appearance while maintaining properties of charcoal such as dehumidification, moisturization, ventilation, adsorption and the like, thereby providing air purification effect by adsorbing offensive odor and harmful gas, emitting far-infrared rays and anions, preventing noise, blocking electromagnetic and harmful waves, promoting blood circulation and metabolism and stabilizing mental and physical conditions. According to the present invention, it is possible to prepare a charcoal board laminate by laminating a print thin paper or a non-woven fabric of chemical fibers on the surface of a charcoal board to provide superior appearance, excellent gas adsorption, far-infrared ray emission and electromagnetic shielding effect. The charcoal board laminate can be used as excellent human body-friendly materials of interior finishing elements in residential environments.

Claims

What Is Claimed Is:

1. A method for preparing a charcoal board laminate having excellent gas adsorption effect, decorativeness and functions while maintaining properties of charcoal, the method comprising the steps of: mixing charcoal particles and an adhesive and pressing the mixture 3 or

more times at a temperature of 150 to 200 ^°C and a pressure of 5 to 40kgf/cm² to form a charcoal

board; applying a water based vinyl adhesive on the charcoal board in an amount of 100 to 300g/

m²; laminating a thin paper with a print having a basis weight of 15 to 35 g/m² and a thickness of

0.02 to 0.08 mm on the adhesive layer; and subjecting the laminate to a hot press process at a

temperature of 100 to 150 ^°C and a pressure of 5 to 15kgf/cm².

2. The method according to claim 1, in which the water based vinyl adhesive is polyvinyl acetate emulsion adhesive.

3. A charcoal board laminate comprising a charcoal board layer, an adhesive layer and a print thin paper layer prepared by the method of claim 1.

4. A method for preparing a charcoal board laminate having excellent gas adsorption effect, decorativeness and functions while maintaining properties of charcoal comprising the steps of: mixing charcoal particles and an adhesive and pressing the mixture 3 or more times at a

temperature of 150 to 200 ^°C and a pressure of 5 to 40kgf/cm² to form a charcoal board; applying

a water based vinyl adhesive on the charcoal board in an amount of 100 to 300g/m²; laminating a

non-woven fabric of chemical fibers having a basis weight of 20 to 40g/m², a thickness of 0.05 to

0.30 mm and porosity of 30 to 50% on the adhesive layer; and subjecting the laminate to a hot press process at a temperature of 100 to 150^°C and a pressure of 5 to 15kgf/cm².

5. The method according to claim 4, in which the water based vinyl adhesive is polyvinyl acetate emulsion adhesive.

6. A charcoal board laminate comprising a charcoal board layer, an adhesive layer and a non- woven fabric layer of chemical fibers prepared by the method of claim 4.