JPH09155813A - Compressed wood material and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a compressed state by providing a thin high specific gravity layer compressed by heating compression to the upper and rear surfaces of a wooden material of which the water content is adjusted to a fiber saturated point or less. SOLUTION: A wooden material of which both upper and rear surfaces are high in temp. is inserted into the gap between the upper and lower hot plates of a hot press device having a thickness prescribing jig attached thereto to be compressed under heating and pressure to form thin high specific gravity layers to both upper and rear surfaces of the wooden material by heating compression. Thin high specific gravity layers 2, 2 compressed by heating compression are provided to the upper and lower surfaces of the wooden material of which the water content is adjusted to a fiber saturated point or less. By this method, a compressed wooden material 1 is obtained. Since the thin high specific gravity layers are formed on the upper and rear surfaces of the wooden material, bending strength, surface smoothness and surface hardness are enhanced in spite of light wt. Since inside and outside balance is kept, the compressed wooden material generating no warpage or twist is obtained.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は木質材を加熱圧縮し
て得られる圧縮木質材に関する。TECHNICAL FIELD The present invention relates to a compressed wood material obtained by heating and compressing wood material.

【０００２】[0002]

【従来の技術】従来の圧縮木質材は、木質材を湿潤状態
で或いは水蒸気雰囲気中で加湿加温して高含水率・高温
状態とした後、加熱圧縮して製造されている。2. Description of the Related Art A conventional compressed wood material is manufactured by heating and compressing the wood material in a wet state or in a steam atmosphere to obtain a high water content and high temperature.

【０００３】上記従来技術は、木質材中に多量の水分が
存在する状態で高温の中で加熱圧縮して圧縮木質材を得
るものであり、セルロース、ヘミセルロース、リグニン
等の木材成分を軟化させ、特に非結晶成分であるヘミセ
ルロース及びリグニンに対しては水分が可塑剤として大
きく作用してそれらの軟化温度をそれぞれ約６０℃にま
で低下させ、木質材の可塑性を増大させつつ加熱圧縮を
行うものである。The above-mentioned prior art is to obtain a compressed wood material by heating and compressing it at a high temperature in the presence of a large amount of water in the wood material, and softening wood components such as cellulose, hemicellulose and lignin, Especially for hemicellulose and lignin, which are non-crystalline components, water acts as a plasticizer to lower the softening temperature of each to about 60 ° C, and heat compression is performed while increasing the plasticity of the wood material. is there.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、高含水
率状態で木質材の加熱圧縮を行う従来技術による場合、
木質材の内部に存在する水分の高蒸気圧力が圧締の解圧
時に圧縮状態を復元しようとする力として働き、更に解
圧によるスプリングバック現象と相まって、圧縮状態を
維持することが困難である。However, in the case of the prior art in which a wooden material is heated and compressed in a high water content state,
The high steam pressure of water present inside the wood material acts as a force to restore the compressed state when the pressure is released, and it is difficult to maintain the compressed state in combination with the springback phenomenon due to the pressure release. .

【０００５】また、特に比重の低い木質材においては、
圧縮が容易になされるものの、水分の高蒸気圧力が圧締
の解圧時に一瞬のうちに放出されることによりパンク
（層間剥離）が発生するおそれがある。[0005] Particularly, in the case of wood materials having a low specific gravity,
Although compression is easily performed, puncturing (delamination) may occur due to the instantaneous release of the high steam pressure of water when the compression is released.

【０００６】高蒸気圧力の影響を防止するために、圧締
圧縮状態を保持しつつ冷却することも考えられるが、生
産性がきわめて低く、コストを大幅に上昇させるので実
際的ではない。In order to prevent the effect of high steam pressure, cooling may be considered while maintaining the compression-compressed state, but it is not practical because productivity is extremely low and cost is greatly increased.

【０００７】更に、圧縮化状態を維持することができた
としても、高含水率状態にある木質材全体に亘って圧縮
化されることから、高比重の木質材となってしまう。こ
のことは、圧縮化状態の維持により材積が小さくなり、
製品歩留まりを低下させ、コストを大幅に上昇させるこ
とを意味している。[0007] Further, even if the compressed state can be maintained, the wood material is compressed over the entire wood material in a high water content state, so that the wood material has a high specific gravity. This means that the volume is reduced by maintaining the compressed state,
This means lower product yields and significantly higher costs.

【０００８】[0008]

【課題を解決するための手段】本発明は上記従来技術に
よる問題点を解決することのできる新規な圧縮木質材及
びその製造方法を提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel compressed wood material and a method for producing the same, which can solve the above problems of the prior art.

【０００９】すなわち、本発明による圧縮木質材は、繊
維飽和点以下に含水率調整された木質材の表裏面に、加
熱圧縮により圧縮化された薄い高比重層が設けられて成
ることを特徴とする。That is, the compressed wood material according to the present invention is characterized in that a thin high specific gravity layer compressed by heat compression is provided on the front and back surfaces of the wood material whose water content is adjusted to a fiber saturation point or lower. To do.

【００１０】また、本発明による圧縮木質材の製造方法
は、繊維飽和点以下に含水率調整された木質材を、その
表裏面を予備加熱して表裏材温を高めると共に、材温が
高いうちに木質材の結晶成分であるセルロースの軟化点
以上の温度にて加熱圧縮し、その後解圧冷却することに
より、木質材の表裏面に圧縮化された薄い高比重層を形
成することを特徴とする。In the method for producing a compressed wood material according to the present invention, the wood material whose water content is adjusted to the fiber saturation point or lower is preheated to increase the front and back material temperatures, and It is characterized by forming a compressed thin high specific gravity layer on the front and back surfaces of wood by heating and compressing at a temperature above the softening point of cellulose, which is the crystalline component of wood, and then decompressing and cooling. To do.

【００１１】[0011]

【発明の実施の形態】木質材としては、木材の挽材或い
は集成材、単板積層材、合板、パーティクルボード、繊
維板等の加工材が用いられる。BEST MODE FOR CARRYING OUT THE INVENTION As the wood material, a processed material such as sawn wood or laminated wood, laminated veneer wood, plywood, particle board and fiber board is used.

【００１２】これら木質材には針葉樹材及び広葉樹材の
いずれもが使用可能であり、特に柔らかいもの、低比重
のものが好適に用いられる。As the wood materials, both softwood and hardwood can be used, and particularly soft wood and low specific gravity wood are preferably used.

【００１３】木質材は、その含水率を繊維飽和点以下、
好ましくは３５％以下に調整される。このため、木質材
として挽材が用いられる場合、木材を製材前に乾燥した
後挽材とするか、或いは乾燥せずに挽材とした後に乾燥
して得られる。加工材を用いる場合にはその製造過程で
繊維飽和点以下に含水率調整される。Wood materials have a water content below the fiber saturation point,
Preferably, it is adjusted to 35% or less. For this reason, when a sawn timber is used as the wood material, it is obtained by drying the wood before sawing it into a sawn sawn timber, or without drying it into a sawn timber and then drying. When a processed material is used, the water content is adjusted to a fiber saturation point or lower during the manufacturing process.

【００１４】繊維飽和点以下に含水率調整された木質材
に対し、その少なくとも表裏面を予備加熱して表裏材温
を高める。At least the front and back surfaces of a wood material whose water content has been adjusted to a temperature below the fiber saturation point are preheated to raise the temperature of the front and back materials.

【００１５】予備加熱は、木質材をドライヤーに投入し
たり、熱盤間に挟む等の任意の方法で行われ、その表裏
材温を高める。好ましくは表裏面における材温が８０℃
以上となるように予備加熱する。Preheating is performed by an arbitrary method such as putting a wood material in a dryer or sandwiching it between hot plates to raise the temperature of the front and back materials. Preferably the material temperature on the front and back is 80 ° C
Preheating is performed so as to become the above.

【００１６】次に、材温が高いうちに、上下の熱盤の間
隔を規制する厚さ規制治具（一般にディスタンスバーと
呼ばれる）が取り付けられたホットプレス装置の熱盤間
に、予備加熱した木質材を挿入する。Next, while the material temperature was high, preheating was performed between the hot plates of the hot press machine to which a thickness regulating jig (generally called a distance bar) for regulating the interval between the upper and lower hot plates was attached. Insert wood.

【００１７】熱盤間の厚さ規制治具は、木質材の厚さの
６０〜９５％、より好ましくは６５〜９２％の厚さを有
するものが好適に用いられる。換言すれば木質材の圧縮
率が５〜４０％、より好ましくは８〜３５％となるよう
に厚さ規制治具が取り付けられる。A jig having a thickness of 60 to 95% of the thickness of the wood material, more preferably 65 to 92%, is preferably used as the thickness control jig between the heating plates. In other words, the thickness regulating jig is attached so that the compressibility of the wood material is 5 to 40%, more preferably 8 to 35%.

【００１８】木質材の圧縮率が５％未満であると、表裏
両面に対する圧縮化が不十分となり、高比重層として必
要な強度を得ることができない。逆に、圧縮率が４０％
を超えると、表裏両面の圧縮化は十分に行われて高比重
層としての必要強度が得られるものの、全体比重が高く
なって重量増を招き、また過大な圧縮率を与えることに
よる材積の減少、すなわち原材料のロスが大きくなるた
めに歩留まりが低下し、コストアップの原因となるので
好ましくない。If the compressibility of the wood material is less than 5%, the compression on both the front and back surfaces becomes insufficient, and the strength required for the high specific gravity layer cannot be obtained. Conversely, the compression rate is 40%
If it exceeds the above, the front and back surfaces will be sufficiently compressed to obtain the required strength as a high specific gravity layer, but the overall specific gravity will increase, leading to an increase in weight, and a decrease in volume due to an excessive compression ratio. That is, since the loss of raw materials increases, the yield decreases, which causes an increase in cost, which is not preferable.

【００１９】木質材の圧縮率は、上記範囲内において、
使用する木質材の樹種、比重、得ようとする表裏面の硬
度等に応じて任意に選択することができ、その選択され
た圧縮率に対応して厚さ規制治具をセットする。The compressibility of the wood material is within the above range.
It can be arbitrarily selected according to the tree species of the wood material to be used, the specific gravity, the hardness of the front and back surfaces to be obtained, etc., and the thickness regulating jig is set according to the selected compression rate.

【００２０】表裏両面の材温が高い木質材を、上記厚さ
規制治具が取り付けられたホットプレス装置の上下熱盤
間に挿入して熱圧圧締することにより、表裏両面に加熱
圧縮による薄い高比重層が形成される。By inserting a wood material having a high material temperature on both the front and back sides into the upper and lower hot plates of a hot press equipped with the above-mentioned thickness regulating jig and hot-pressing it, the front and back surfaces are thinned by heating and compression. A high specific gravity layer is formed.

【００２１】木質材の予備加熱を熱盤により行う場合に
は、木質材をホットプレス装置の熱盤間に挿入し、熱盤
に圧力をかけずに或いは木質材が変形しない程度の軽微
な圧力をかけて木質材に接触させ、この接触状態を保持
して予備加熱を行い、次いで、木質材に所定の圧縮率を
与えるために必要な圧力を該熱盤に加えて熱圧圧締し
て、表裏両面に圧縮化された高比重層を形成することが
できる。When the wood material is preheated by the hot platen, the wood material is inserted between the hot plates of the hot press machine, and a slight pressure is applied without applying pressure to the hot plate or the wood material is not deformed. To contact the wood material, preheat while maintaining this contact state, then apply the pressure necessary to give a predetermined compressibility to the wood material to the hot platen and hot press it, A compressed high specific gravity layer can be formed on both front and back surfaces.

【００２２】このようにホットプレス装置による予備加
熱及び加熱圧縮を１サイクルで行う圧縮方法によれば、
木質材を搬送する必要がなく、ホットプレス装置のプレ
ススケジュールの設定だけで容易に実施可能である。こ
のため、木質材を損傷させることがなく、熱効率が良
く、設備が簡略化され、プレススケジュールの設定が容
易に変更可能であって種々の木質材に対応することがで
き、圧縮率等の製品仕様の変更も容易であり、生産効率
に優れ、歩留まりが良好である等の利点が発揮される。As described above, according to the compression method in which the preheating and the heat compression by the hot press device are performed in one cycle,
It is not necessary to convey a wood material, and it can be easily performed only by setting the press schedule of the hot press device. Therefore, the wood material is not damaged, the thermal efficiency is good, the equipment is simplified, the setting of the press schedule can be easily changed, and it can be applied to various wood materials. The specifications can be easily changed, and the advantages such as excellent production efficiency and good yield are exhibited.

【００２３】木質材の熱圧圧締は、その熱圧温度を、木
質材の結晶成分であるセルロースの軟化点以上の温度と
して行われる。The hot-pressing of the wood material is carried out at a hot-pressing temperature which is equal to or higher than the softening point of cellulose which is a crystalline component of the wood material.

【００２４】木質材中の結晶成分であるセルロースの軟
化点温度は、樹種によって若干異なるものの、概ね２０
０〜２５０℃であり、しかも木質材の含水率にかかわら
ずほぼ一定している。従って、本発明では熱圧温度を２
００℃以上として圧締する必要がある。The softening point temperature of cellulose, which is a crystalline component in wood, is about 20 although it varies slightly depending on the tree species.
The temperature is 0 to 250 ° C. and is almost constant regardless of the water content of the wood material. Therefore, in the present invention, the hot pressing temperature is set to 2
It is necessary to clamp at a temperature of 00 ° C or higher.

【００２５】なお、木質材の非結晶成分であるヘミセル
ロース、リグニンの軟化点温度は木質材の含水率によっ
て大きく変化し、絶乾状態におけるヘミセルロース及び
リグニンの軟化点温度はそれぞれ約１８０℃、約１５０
℃であるが、木質材の繊維飽和点である３５％の含水率
においては共に軟化点温度が６０℃付近にまで低下す
る。従って、繊維飽和点以下に含水率調整された木質材
を用いる本発明において、セルロースの軟化点以上の温
度で熱圧圧締することにより、結晶成分であるセルロー
スが熱軟化すると同時に、非結晶成分であるヘミセルロ
ース及びリグニンも軟化溶融する。The softening point temperatures of hemicellulose and lignin, which are non-crystalline components of wood, vary greatly depending on the water content of the wood, and the softening temperatures of hemicellulose and lignin in an absolutely dry state are about 180 ° C. and about 150 ° C., respectively.
However, at a water content of 35%, which is the fiber saturation point of the wood material, the softening point temperature decreases to around 60 ° C. Therefore, in the present invention using a wood material whose water content is adjusted to a fiber saturation point or lower, by hot pressing at a temperature equal to or higher than the softening point of cellulose, the cellulose that is a crystalline component is thermally softened, and at the same time, an amorphous component is used. Certain hemicelluloses and lignin also soften and melt.

【００２６】圧締時間及び圧締圧力は、使用する木質材
の種類、樹種、材自体の比重、柔らかさ等に応じて任意
に設定されるが、圧締の際に前記厚さ規制治具による必
要圧縮率を得るためには一般に圧締時間１〜７分、圧締
圧力５〜２５ｋｇ／ｃｍ２とすることが好ましい。The pressing time and the pressing pressure are arbitrarily set according to the type of wood material to be used, the type of wood, the specific gravity of the material itself, the softness, etc. In order to obtain the required compression rate according to (1), it is generally preferable to set a pressing time of 1 to 7 minutes and a pressing pressure of 5 to 25 kg / cm 2.

【００２７】ホットプレス装置の上下熱盤間にて加熱圧
縮された木質材は、予めその表裏両面を予備加熱されて
表裏材温が高いものとされているため、熱盤の熱が直ち
に表裏部分に伝わり、該表裏部分において熱軟化及び圧
縮力による圧縮化が進行するが、繊維飽和点以下の含水
率に調整されていることから、熱伝達は比較的緩慢に行
われ、従って木質材の表裏部分のみが圧縮化される。The wood material which is heated and compressed between the upper and lower hot plates of the hot press machine is preheated on both the front and back sides in advance so that the front and back material temperatures are high. However, since heat softening and compression by the compression force proceed in the front and back parts, the heat transfer is relatively slow because the water content is adjusted to the fiber saturation point or lower, and therefore the front and back surfaces of the wood material are Only the part is compressed.

【００２８】このように、熱圧時においても木質材全体
の温度が高くなることがないため、その後の解圧により
容易に冷却される。In this way, the temperature of the entire wood material does not rise even during hot pressing, so it is easily cooled by subsequent decompression.

【００２９】しかも、木質材組織中の結晶成分であるセ
ルロースの軟化点以上の温度で熱圧圧縮されるため、熱
圧時に軟化した繊維質のセルロースが解圧後の冷却によ
り変形した状態で固定される。更に、非結晶成分である
ヘミセルロース、リグニンも熱圧により軟化溶融してセ
ルロースに対して接着剤として作用するため、熱圧圧締
後の解圧に伴う木質材のスプリングバックが最小限に抑
えられ、表裏両面に圧縮化された薄い高比重層が形成さ
れる。Moreover, since it is hot-pressed at a temperature equal to or higher than the softening point of cellulose, which is a crystalline component in the woody tissue, the fibrous cellulose softened during hot pressing is fixed in a deformed state by cooling after decompression. To be done. Furthermore, since hemicellulose, which is an amorphous component, lignin also softens and melts by heat pressure and acts as an adhesive to cellulose, springback of the wood material due to decompression after hot pressing is suppressed to a minimum, A compressed thin high specific gravity layer is formed on both front and back surfaces.

【００３０】木質材の表裏両面に圧縮化により形成され
る薄い高比重層は、好ましくは０．７以上の比重を有す
る。The thin high specific gravity layers formed by compression on both front and back surfaces of the wood material preferably have a specific gravity of 0.7 or more.

【００３１】また、該高比重層の硬さは，ＪＩＳ Ｚ−
２００７による木材の硬さ試験法において１．５ｋｇｆ
／ｍｍ２以上であることが好ましく、これにより表面の
耐衝撃性が十分なものとなって傷がつきにくくなり、材
自体の曲げ強度を向上させると共に、疎水性、膨潤率、
吸水率の減少により木質材としての寸法安定性を向上さ
せる。The hardness of the high specific gravity layer is JIS Z-
1.5 kgf in the hardness test method of wood according to 2007
/ Mm2 or more is preferable, whereby the impact resistance of the surface is sufficient, scratches are less likely to occur, the bending strength of the material itself is improved, and the hydrophobicity, swelling ratio,
Improves dimensional stability as a wood material by reducing water absorption.

【００３２】以上のようにして、繊維飽和点以下に含水
率調整された木質材の表裏面に、加熱圧縮により圧縮化
された薄い高比重層２、２が設けられて成ることを特徴
とする本発明の圧縮木質材１が得られる（図１）。As described above, the thin high specific gravity layers 2 and 2 which are compressed by heat compression are provided on the front and back surfaces of the wood material whose water content is adjusted to the fiber saturation point or lower. The compressed wood material 1 of the present invention is obtained (FIG. 1).

【００３３】[0033]

【発明の効果】本発明によれば、全体比重を高めること
なく、木質材の表裏面に薄い高比重層が形成されるた
め、軽量でありながら曲げ強度、表面平滑性、表面硬度
の向上がなされ、また表裏のバランスが保たれることか
ら反りやねじれを発生させることのない圧縮木質材が得
られる。According to the present invention, thin high specific gravity layers are formed on the front and back surfaces of a wood material without increasing the overall specific gravity. Therefore, the bending strength, surface smoothness, and surface hardness are improved while being lightweight. Moreover, since the front and back surfaces are kept in balance, a compressed wood material that does not warp or twist can be obtained.

【００３４】表裏両面の高比重層は、木質材の結晶成分
であるセルロースが軟化され、また非結晶成分であるヘ
ミセルロース、リグニンが軟化溶融された後に圧縮され
て高比重に硬化して形成されるものであるため、疎水性
の被膜となり、圧縮化による親水性の低減と相まって、
膨潤率及び吸水率を減少させることができ、木質材の寸
法安定性を大幅に向上させる。The high specific gravity layers on both the front and back sides are formed by softening cellulose, which is a crystalline component of wood, and softening and melting non-crystalline components, hemicellulose and lignin, and then compressing and hardening them to a high specific gravity. Since it is a material, it becomes a hydrophobic film, and coupled with the reduction of hydrophilicity due to compression,
The swelling rate and the water absorption rate can be reduced, and the dimensional stability of the wood material is significantly improved.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明による圧縮木質材の概略構成を示す断面
図である。FIG. 1 is a sectional view showing a schematic configuration of a compressed wood material according to the present invention.

【符号の説明】[Explanation of symbols]

１ 圧縮木質材 ２ 高比重層 1 Compressed wood 2 High specific gravity layer

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 繊維飽和点以下に含水率調整された木質
材の表裏面に、加熱圧縮により圧縮化された薄い高比重
層が設けられて成ることを特徴とする圧縮木質材。1. A compressed wood material, characterized in that a thin high specific gravity layer compressed by heat compression is provided on the front and back surfaces of the wood material whose water content is adjusted to a fiber saturation point or lower. 【請求項２】 繊維飽和点以下に含水率調整された木質
材を、その表裏面を予備加熱して表裏材温を高めると共
に、材温が高いうちに木質材の結晶成分であるセルロー
スの軟化点以上の温度にて加熱圧縮し、その後解圧冷却
することにより、木質材の表裏面に圧縮化された薄い高
比重層を形成することを特徴とする圧縮木質材の製造方
法。2. A wood material whose water content is adjusted to a fiber saturation point or lower to preheat the front and back surfaces of the wood material to raise the temperature of the front and back materials, and soften cellulose which is a crystalline component of the wood material while the wood temperature is high. A method for producing a compressed wood material, which comprises forming a compressed thin high specific gravity layer on the front and back surfaces of the wood material by heating and compressing at a temperature above a point and then decompressing and cooling.