JP3520962B2 - Method for modifying wood and modified wood obtained thereby - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for modifying wood and modified wood, and more particularly to a method for reducing the vibration damping ratio (tan δ) of wood to obtain modified wood suitable as a musical instrument member.

[0002]

2. Description of the Related Art Conventionally, research has been conducted on modifying wood by various chemical treatments. For example, in the Journal of Wood Science Vol.38, No.12 p.1119-1125 (1992, Hiroyuki Yano, etc.), wood was soaked in an aqueous resorcin solution, air-dried, and then heated in formaldehyde vapor. , Reduction of tan δ, improvement of strength, reduction of hygroscopicity, improvement of dimensional stability, etc. are achieved.

[0003]

However, such a modification treatment using resorcin and formaldehyde is complicated in processing work, and the modified wood has a formaldehyde odor and an increase in weight. Was relatively large, and the treatment made it brittle in terms of material quality.

The present invention has been made in view of the above circumstances, and a method for modifying wood, which can reduce the vibration damping ratio (tan δ) of wood without using the conventional method using resorcin and formaldehyde, and The object is to provide a modified wood obtained by this.

[0005]

Means for Solving the Problems The present inventors have used Pernambuco (Pe
rnambuco; a broad-leaved tree of the leguminous family) has an extremely low vibration damping rate (tan δ) compared to other hardwoods. The present invention has been completed by discovering that a compound having γ greatly contributes to the reduction of tan δ. That is, in order to solve the above-mentioned problems, the method for modifying wood according to the present invention comprises the steps of impregnating or applying wood with a solution containing hematoxylin and / or a derivative thereof, and then drying until the desired water content is reached. And a process. The modified wood of the present invention,
It is permeated with a solution containing hematoxylin and / or a derivative thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The hematoxylin used in the present invention has a molecular structure represented by the following chemical formula (I).
It is known to exist in the wood of Haematoxylon campechianum. Further, in the present invention, this hematoxylin derivative can be used in the same manner, and hematoxylin and its derivative may be mixed and used.

[Chemical 1]

In the present invention, hematoxylin and / or
Alternatively, the derivative is used by dissolving it in an appropriate solvent. Any solvent can be used as long as it can dissolve hematoxylin and its derivatives, but water or alcohol solvents are preferably used because they are easy to handle. If the concentration of hematoxylin and its derivatives in the solution is too low, the effect of lowering tan δ will not be sufficiently obtained, and if it is too high, the specific gravity of the wood to be modified may be greatly increased. % Range is preferred,
It is set according to the characteristics of the wood used as the material and the intended use and characteristics of the modified wood to be obtained.

As the wood used as a material, suitable wood can be used depending on the intended use of the modified wood to be obtained, etc., but if necessary, even if the extraction component in the wood is extracted and removed beforehand. Good. This extraction component can be removed by a known extraction method using an appropriate solvent such as a mixed solution of benzene and ethanol.

In the method for modifying wood according to the present invention, first, a hematoxylin solution is prepared and the wood material is impregnated with the hematoxylin solution.
As a method of impregnation, wood may be dipped in the solution, but at the same time, a technique advantageous for impregnation such as depressurization, pressurization, or depressurization and pressurization can be appropriately used. Alternatively, the hematoxylin solution may be applied to the wood. At this time, the amount of the hematoxylin solution impregnated and the amount applied is 10 to 10.
500 g / m ² is suitable.

Then, the modified wood is obtained by drying the wood that has been infiltrated with the hematoxylin solution until the desired water content is obtained. Drying can be performed using a well-known method for drying wood, such as air drying, heat drying, heat drying under reduced pressure, or a combination thereof. The desired water content is set according to the intended use of the modified wood, etc., but is preferably set in the range of, for example, 5 to 15%.

The modified wood thus obtained has a greatly reduced tan δ as compared with the material wood, the weight increase due to the penetration of the hematoxylin solution is relatively small, and the strength does not decrease. Such modified wood is suitable as a soundboard for wooden musical instruments such as piano, guitar, violin, and percussion. In particular, an increase in specific gravity is an index when converting the vibration of a string into a sound, and a small increase in weight is preferable as a material for a soundboard. Further, the method for modifying wood according to the present invention uses a natural component called hematoxylin and can be treated without using a chemical agent having an offensive odor such as formaldehyde. Further, there is an advantage that the treatment can be carried out by a simple step of drying after impregnating or applying the hematoxylin solution to the wood and no special equipment is required.

Hereinafter, the effects of the present invention will be clarified by showing concrete examples. The present invention is not limited to the following specific examples. In the following specific examples and comparative examples, as a wood sample, Sitka spruce (Picea sitchensis) selected for piano soundboard was used. 2 mm for measurement
(Tangential direction: T) x 12 mm (radial direction: R) x 150
A fiber direction sample of mm (fiber direction: L) was used. This wood sample had ethanol and benzene in a weight ratio of 1: beforehand.
After performing extraction treatment using the mixed liquid mixed in 2, dried at 60 ° C. under reduced pressure for 24 hours, the weight was measured, and this was taken as the weight before the modification treatment. Further, after performing humidity control treatment for 2 weeks in an atmosphere of 20 ° C. and 65% RH, the vibration characteristic was measured and set as the vibration characteristic value before the modification treatment. Vibration characteristics are measured by the flexural vibration method with free ends (Yano et al .: Mokuzai Gakkaishi, 32, 984-989 (19)
86)) was used to determine the specific Young's modulus from the resonance frequency by the Euller-Bernoulli equation. The logarithmic decay rate was obtained from the free decay curve, divided by π and converted to tan δ.

(Specific Example 1) First, a 1 to 2 wt% aqueous solution of a hematoxylin powder sample was prepared. The above wood sample was immersed in this aqueous solution at room temperature and atmospheric pressure for 1 week for impregnation.
After the immersion, air-drying was carried out for 2 to 3 days, followed by drying at 60 ° C. under reduced pressure for 24 hours to obtain modified wood. The weight of the obtained modified wood was measured and used as the weight after the modification treatment. 20 more
After conditioning for 2 weeks at 65 ° C and 65% RH,
The vibration characteristic was measured and used as the vibration characteristic value after the modification treatment. (Comparative Examples 1 to 5) The modification treatment was performed under the same conditions except that the following polyfunctional aromatic compounds were used in place of hematoxylin in the above-mentioned Specific Example 1. The compounds used were pyrogallol (Comparative Example 1), catechol (Comparative Example 2), resorcin (Comparative Example 3), saligenin (Comparative Example 4), and salicin (Comparative Example 5). Further, the weight and the vibration characteristic value after the modification treatment were measured in the same manner as in Example 1.

For each of the above-mentioned specific examples and comparative examples, the weight increase rate (%) after the reforming treatment with respect to before the reforming treatment
I asked. Further, the rate of change of the specific dynamic Young's modulus and the rate of change of tan δ after the modification treatment with respect to before the modification treatment were obtained. The results are shown in Table 1 below. In addition, Table 1 shows the measured values of two sample pieces treated under the same conditions.

[0015]

[Table 1]

From the results shown in Table 1, the modified wood impregnated with hematoxylin has a vibration damping ratio tan δ of about 3% as compared with that before the modification treatment, although the weight increase rate is small at about 3%. It can be seen that it is reduced by 40%. On the other hand, in the case of impregnation with other polyfunctional aromatic compounds, ta
No decrease in nδ was observed. Also, focusing on two sample pieces impregnated with hematoxylin under the same conditions and dried,
Although there is a difference in the rate of change in weight, almost the same reduction in tan δ of 40% or more has been achieved. From this,
The higher the amount of hematoxylin solution impregnated into wood, the more tan δ
It can be seen that a lower tan δ is obtained with a small amount of impregnation (weight increase rate) rather than a more significant reduction in

[0017]

As described above, according to the present invention, a solution containing hematoxylin and / or a derivative thereof is impregnated into or applied to wood and then dried to a desired water content by a simple process. A modification process can be performed. Therefore, since complicated processing and special equipment are not required, it can be carried out easily and at low cost. Further, the method for modifying wood according to the present invention uses a natural component called hematoxylin, and has an advantage that it can be treated without using a chemical agent having an offensive odor such as formaldehyde. The modified wood of the present invention is impregnated with a solution containing hematoxylin and / or a derivative thereof, and the vibration damping ratio (ta
A large decrease in nδ) is achieved and no decrease in strength occurs. Such modified wood is particularly suitable as a soundboard for wooden musical instruments.

Front Page Continuation (73) Patent Holder 598163949 Masahiro Matsunaga 41 Jodoji Temple, Shimodantacho, Sakyo-ku, Kyoto City, Kyoto 101 Corp. Jodoji Temple (73) Patent Holder 598163950 Fumiaki Nakatsubo 25-58 (72) Gokashoichirizuka, Uji City, Kyoto Prefecture ) Inventor Kazuya Minato 6-13-4 Oedashinishibayashi, Nishikyo-ku, Kyoto-shi, Kyoto Prefecture (72) Inventor Keiko Sakai 2-3, Ichijoji Higashisuginomiya-cho, Sakyo-ku, Kyoto-shi, Kyoto Prefecture (72) Masahiro Matsunaga 41 Shimonanta-cho, Sakyo-ku, Kyoto-shi, Kyoto Prefecture 101 Kopo Jodo-ji 101 (72) Inventor Fumiaki Nakatsubo 25-58 Gokashoichirizuka, Uji-shi, Kyoto Prefecture 58-58 (58) Fields investigated (Int.Cl. ⁷ , DB name) B27K 3 / 38

Claims (2)

(57) [Claims] 1. A method for modifying wood, comprising the steps of impregnating or coating wood with a solution containing hematoxylin and / or a derivative thereof, and then drying the wood to a desired water content. . 2. Modified wood impregnated with a solution containing hematoxylin and / or its derivatives.