KR100614601B1 - an wood particle sound-absorbing board and a manufacturing method therefor - Google Patents

Abstract

The present invention relates to a method for producing a wood sound absorbing material by recycling wood-based and non-wood-based waste, the step of adding about 5 to 30% by weight of a synthetic resin adhesive to the wood particles in a weight ratio, and stirring the adhesive and agitated wood particles The step of forming into a mat and putting the mat in a forming mold having a plurality of discharge holes on the main surface, interposing the upper and lower cowles each having a plurality of core pins of different diameters to be coaxial with each other, and then Pressing at the bottom, the pressing step being carried out at a pressure of about 20 to 40 kg / cm 2 at a temperature of about 140 to 240 ° C. for at least 5 minutes. The method of the present invention can provide a wood board having a low specific gravity thick plate and sufficient self-strength, as well as a remarkable sound absorption improvement by forming a resonator. Accordingly, it can be applied to environmentally friendly interior and exterior materials harmless to the human body by replacing the heat-insulating and sound-absorbing materials, such as conventional glass fiber or rock wool and gypsum board.

Particle Board, Wood Sound Absorbing Material, Resonance Hole, Sound Absorption Rate

Description

Wood sound absorbing material and manufacturing method therefor {an wood particle sound-absorbing board and a manufacturing method therefor}

1 is a cross-sectional view schematically showing the main part of a general wood board manufacturing method,

Figure 2 is a block diagram sequentially showing a sound absorbing material manufacturing process according to the present invention,

Figure 3a and Figure 3b is a cross-sectional view schematically showing the main portion of the sound absorbing material manufacturing method according to the present invention,

Figure 4 is a perspective view of the sound absorbing material produced by the method of the present invention,

5 is a cross-sectional view taken along the line VV of FIG. 4;

6A and 6B are cross-sectional views showing various forms of voids in the sound absorbing material of the present invention;

7 is a comparative graph showing the sound absorption performance of the wood sound absorbing material according to the present invention and the conventional material and the particle board,

8 is a comparison graph showing the prediction resonance frequency and the observation resonance frequency of the wood sound absorbing material of the present invention.

<Explanation of symbols for main parts of drawing>

1: Molding hole 2: Outlet hole (in mold)

3, 4: press 5, 7: cowl

6, 8: core pin (cow's) 9: wood mat

10: wood sound absorbing material 11: resonance hole (of wood sound absorbing material)

The present invention relates to a wood sound absorbing material and a method for manufacturing the same, and more particularly, to recycle wood waste and non-wood waste such as to recycle the waste resources to produce a wood sound absorbing material that can be applied to the building interior and exterior materials, etc. A method and a wood sound absorbing material produced thereby.

Wood is a renewable natural resource, which is beautiful in appearance and excellent in processability. Although it is somewhat different depending on the species, it has a relatively excellent strength compared to other materials, so it is widely used in various industrial fields such as building materials. However, wood has a high absorbency and hygroscopicity, which is not only poor in dimensional stability, but also has a sound absorption rate of about 5%. Accordingly, when the wood is pulverized into particles and then recombined using an adhesive, it is known to have excellent dimensional stability as well as to improve sound absorption due to the influence of voids formed at the time of manufacture.

On the other hand, the wood-related industry inevitably generates a large amount of waste ash as a by-product of processing. Among these waste wood wastes, low-weight wood waste is used as a raw material for particle board or fiber board, which is a wood plate material. It is only a part that is used as a livestock rug.

Conventional wood particleboard or fiberboard is a mixture of wood particles or wood fibers with a synthetic resin to form a mat (mat), as shown in Figure 1 and the cowl (caul: C) on the top and bottom of the mat (M) A board is manufactured by crimping | bonding with a press (P: P) through it. However, the conventional particle board or fiberboard manufactured by this method is a problem in the manufacturing method due to the high specific gravity of the board and inferior physical and mechanical properties, which are mostly used only as kitchen furniture or office furniture, and are extremely difficult to use as interior and exterior materials of construction. . In addition, it is virtually impossible to manufacture a board having a thickness of 35 mm or more, and even if manufactured, it does not have sufficient self-strength and thus cannot be used as various materials.

That is, in order to manufacture a wood board having a thickness of 35 mm or more due to the characteristics of the wood waste material, the height of the primary molded mat M is at least 600 mm, and is formed very high, and the mat M having such a height is pressed (P). ), The mat M is pushed or collapsed to the open side of the thermoforming machine and the shape of the mat M is destroyed. In particular, the upper and lower surface portions of the mat M, which are directly subjected to pressure, have a faster pressure transfer than the center layer, so that the added synthetic resin is cured quickly. However, the pressure is sufficiently transmitted in the center layer of the mat M. This prevents sufficient curing of the adhesive. As a result, the wood board manufactured according to the thickness direction of the density difference from the surface layer to the deep layer is severely generated and various physical and mechanical properties are degraded.

Accordingly, glass fiber, rock wool, and gypsum board are used as interior and exterior materials, especially sound absorbing materials, and they are mainly used in buildings because of their good sound absorption and heat insulating properties. However, these sound absorbing materials not only have a harmful effect on the human body by dust or the like when exposed to air, but due to its characteristics, the strength of the material itself is very weak, so that the sound absorbing materials have to be provided with a separate constant frame. In addition, due to its own weight, it may be driven to a lower portion as time passes, causing a decrease in sound absorption rate.

The present invention has been completed in view of the above-described conventional problems, and an object thereof is to provide a wooden sound absorbing material which has high sound absorption and proper thermal insulation and which is not harmful to the human body at all.

Another object of the present invention is to provide a wood sound absorbing material having a low specific gravity plate having a thickness of 35 mm or more and having sufficient self strength as a material, and which does not require a separate support frame.

Another object of the present invention is to provide a method for producing a wood sound absorbing material suitable for producing a wood sound absorbing material of the above-described object.

It is still another object of the present invention to provide a method for producing wood sound absorbing materials by recycling wood and non-wood waste materials.

In order to achieve the above objects, the wood sound absorbing material according to the present invention is manufactured by mixing wood particles with a suitable amount of a synthetic resin adhesive and then compressing them, characterized in that a plurality of stepped resonance holes are formed in the thickness direction.

In addition, the method for producing a wood sound absorbing material according to the present invention comprises the steps of adding about 5 to 30% of a synthetic resin adhesive by weight to wood particles and stirring; Molding the resin adhesive and the stirred wood particles into mats of the required thickness; And a mat placed in a forming mold in which a plurality of discharge holes are formed on the main surface, and interposing the upper and lower cowls each having a plurality of core pins of different diameters coaxially with each other. Pressing the press from the bottom; characterized in that consisting of.

According to one preferred feature of the manufacturing method of the present invention, the pressing step is performed at a pressure of about 20 to 40 kg / ㎠ at a temperature of about 140 to 240 ℃ at least 5 minutes or more, preferably at a pressure of 35 kg / ㎠ 10 5 minutes at a pressure of 30 kg / ㎠, a multi-step method is carried out sequentially for 5 minutes at a pressure of 20 kg / ㎠.

According to another preferred feature of the production method of the present invention, it further comprises a post-treatment step of applying at least one of a flame retardant, a water-resistant agent and a colorant to the surface of the compression-molded wood sound absorbing material.

Accordingly, the present invention can provide a new type of wood sound absorbing material that is harmless to the human body with sound absorption and heat insulation, as well as recycling the low cost wood-based waste resources, thereby increasing the usability of the wood waste material. It is possible to manufacture a low specific gravity thick plate with a thickness of 35 mm or more that could not be manufactured to have sufficient self-strength.

Specific features and other advantages of the present invention will become more apparent from the following description of the preferred embodiments with reference to the attached drawings.

First, a method of manufacturing a wooden sound absorbing plate according to the present invention will be described with reference to FIG. 2.

In step 110, the wood waste is pulverized into particles using a grinder such as a chipper. At this time, if the wood-based waste is waste particles in the form of particles generated during the processing of wood, such as sawdust, may be used as it is without additional grinding.

In step 120, the pulverized wood particles and the resin adhesive is added to the stirrer and mixed. At this time, the amount of the adhesive is suitably about 5 to 30% by weight relative to the wood particles, preferably 10 to 20% is mixed. As the synthetic resin adhesive, any one of an adhesive group consisting of urea resin, melamine resin, phenol resin, urethane resin, and isocyanate resin may be used, and isocyanate resin is preferably used.

On the other hand, in the stirring step, non-wood particles, for example, particles made of non-wood waste materials such as polypropylene or polyethylene may be mixed together, in this case, further increase the dimensional stability and bonding strength of the finished wood sound absorbing material. These non-woody particles are also prepared by grinding with a chipper in step 110 described above.

In step 130, the wood particles mixed with the resinous adhesive are molded into mats with the required thickness on the cowl. At this time, the thickness of the wood mat is determined according to the specific gravity of the wood sound absorbing material which is the final product to be manufactured.

In step 140, first, as shown in Fig. 3A, the molded wood mat 9 is placed in the mold 1 having the upper and lower surfaces open, and then stainless steel or the like is placed on the upper and lower parts of the wood mat 9; Each of the plate-shaped cowls 5 and 7 made of metal is placed. On the opposite surface of each cowl 5, 7 a plurality of core pins 6, 8 having different diameters are arranged to be appropriately arranged and projected, with corresponding core pins of both cowls 5, 7 (6) (8) are positioned coaxially with each other.

The diameters and lengths of the core pins 6 and 8 are set to be suitable for the respective noise frequency characteristics of the place where the wood sound absorbing material is used, that is, the office, the conference room, the music room or the roadside.

In addition, a plurality of discharge holes 2 are formed in the main surface of the mold 1 so that, when the wood mat 9 is compressed, hardening of the synthetic resin adhesive and water vapor generated from wood particles can be easily discharged to the outside. It is.

Next, as shown in Fig. 3B, the wood mat 9 accommodated in the molding die is compressed to the presses 3 and 4 on the outside of the two cowls 5 and 7. Then, as the distance between the two cowls (5) (7) is narrowed, the wood mats (9) located between the two are compressed and formed into a wood sound absorbing material of required thickness, which is coaxially opposed to each cowl (5) (7). The core pins 6 and 8 provided as a plurality of resonance holes generated by digging into the wood mat 9 are formed to penetrate in the thickness direction thereof. At this time, the water vapor generated while the synthetic resin adhesive or the like is cured by pressure is easily discharged to the outside through the discharge holes 2 formed in the main surface of the molding die 1 to prevent the generation of steam pressure inside the board.

On the other hand, such pressing is carried out at least 5 minutes at a pressure of 20 to 40 kg / ㎠ at a temperature of about 140 to 240 ℃, 10 minutes, 30 kg / at a pressure of 35 kg / ㎠ for structural stability of wood sound absorbing material It is preferably made of a multi-step method of sequentially performing for 5 minutes at a pressure of 2 cm, 5 minutes at a pressure of 20 kg / cm 2.

As described above, according to the present invention, the wood mat 9 is pressurized in a predetermined mold 1, so that the collapse of the wood mat 0 as in the prior art does not occur at all regardless of the thickness of the wood mat 9. The height rise is made, and the same effect as pressurization can be obtained not only on the upper and lower surfaces of the mat 9 but also on each side. Therefore, the pressure by the presses (3) and (4) is rapidly and relatively evenly transmitted to the depths of the wood mat (9) so that the density gradient between the surface and the depths is formed to a uniform density, and the hardening of the synthetic resin adhesive is performed. Cohesion between particles is greatly improved to be able to produce a wood sound absorbing material having a low specific gravity thick plate and sufficient strength. According to the measurement of the present inventors, while the specific gravity of the conventional wood particle board is 0.7, the wooden sound absorbing material according to the present invention can lower the specific gravity to about 0.3.

As shown in FIGS. 4 and 5, the wood-based sound absorbing material 10 in which the pressing process is completed has a plurality of stepped resonance resonance holes 11 formed in the thickness direction thereof. When the larger diameter is installed in such a resonance hole 11 so as to be in close contact with the wall surface, the sound incident to the smaller diameter is lost due to resonance with air in the space where the large diameter resonance hole 11 forms the wall surface. Accordingly, the wood sound absorbing material 10 is to perform a greatly enhanced sound absorption with its pores. Therefore, by appropriately adjusting the diameter, length, and surface area of the large diameter portion of the resonance hole 11 which substantially performs sound absorption, it is possible to freely manufacture the wood sound absorbing material 10 corresponding to a specific noise frequency band.

Here, the resonance holes 11, 11 ', 11 &quot; are preferably configured in as many stages as possible as shown in Fig. 6A in consideration of the characteristics of sound absorption by resonance, and the diameter is as shown in Fig. 6B. It is more preferable to configure a substantially trapezoidal cross-sectional shape gradually increasing toward the back side.

In step 150, after the surface grinding and humidity control treatment is performed on the compressed wood sound absorbing material 10, in step 160, a post-treatment of selectively applying a flame retardant, a water repellent, a colorant, or the like, or applying all of them. The process is completed to complete the manufacture of the wood sound absorbing material (10).

Next, the sound absorption rate of the wood sound absorbing material 10 of the present invention prepared as described above will be compared with conventional wood boards.

Comparative Example 1

A wooden sound absorbing material having a resonance hole of diameter 9 mm produced by the present invention, a single resonance board in which a resonance hole having a diameter of 18 mm is secondary to a general wooden board produced by the present invention, and a conventional wooden particle board and a white Wood materials were measured and compared by measuring standing wave ratios of frequencies in the frequency range from 125 kHz to 2 kHz according to the Korean Industrial Standard "KS F 2814, Measurement Method of Vertical Incidence Sound Absorption Rate of Building Materials by the In-Place Method." The result is shown in FIG.

In Figure 7, the cypress showed about 5% sound absorption rate, while on the wooden particleboard showed a sound absorption rate of 20% or more in the frequency range of 1 ㎑ or less, the wood sound absorbing material and the single resonance board manufactured by the present invention In this case, the overall sound absorption rate is significantly improved. In particular, in the frequency band around 300 ~ 500 kHz, the sound absorption rate of the test piece of the present invention having a resonance hole was about 20 to 30% higher than that of the conventional particle board.

Comparative Example 2

The prediction resonance frequency predicted by calculating the resonance frequency representing the sound absorption effect peak of the resonance hole and the measured frequency-absorption rate relationship were compared through three test pieces, and the results are shown in FIG. 8.

As can be seen in Figure 8, it can be seen that the theoretical predicted value and the measured value of the test piece closely match, the degree is more accurate than the low frequency region can be seen that.

In view of this result, by providing a resonance hole having a size that can enhance the sound absorption effect in a specific frequency band, it is possible to achieve a high sound absorption effect even in a specific frequency band according to the conditions of use.

On the other hand, the present invention has been described as using only the wood-based waste material or by adding an appropriate amount of non-wood waste to the wood-based waste material to manufacture the suction-up material, but the present invention is not limited to this, but in some cases only the non-wood waste Naturally, the sound absorbing material can be produced in the same manner.

As described above, according to the present invention, the wooden sound absorbing material of the thick plate that can significantly reduce the weight of the conventional particleboard while maintaining sufficient self-strength while compressing the wood mat formed by recycling the wood-based waste in a predetermined molding frame It can be prepared. In particular, the resonant holes formed at the same time as the thermo-pressure molding has a very good sound absorption effect compared to the conventional particle board in a certain frequency band, and thus harmful materials such as glass fiber, rock wool and gypsum board, which were used as insulation and sound absorbing material, Alternatively, it can be applied to environmentally friendly interior and exterior materials harmless to the human body.

In addition, the sound absorbing effect by the resonance hole agrees well with the theoretical predicted value of the resonance frequency, so that it is possible to design various sound absorbing materials suitable for use by forming resonance holes of various sizes that can enhance the sound absorbing effect in a specific frequency band. Become.

Claims (8)

It is manufactured by mixing 5-30% synthetic resin adhesive in wood particles and then compressing them. A large number of stepped resonance holes are formed in the thickness direction, but the diameter of the resonance holes is gradually enlarged toward the rear side, and is formed on the wall surface. The wood sound absorbing material is installed to be in close contact, the resonance space portion is formed in the sound absorbing material itself, the sound absorption characteristics are improved over the entire low frequency and high frequency. delete delete delete delete delete delete delete

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