【考案の詳細な説明】
本考案は、住宅等建築物の下地材、特に内装ク
ロス張り下地材として好適な積層板に関するもの
で、寸法安定性良好で反り現象を生じない建築用
下地材を提供せんとするものである。従来、合板
と木質繊維板を接着した積層板は軽量で加工性や
断熱性にすぐれた建築用下地材としてクロス張り
や化粧板の下地に用いられている。
しかし、上記の合板と木質繊維板は吸放湿性が
あり、吸放湿により伸縮するという性質を有し、
２者の吸湿速度と吸湿線膨脹率が異なるので２者
を接着積層すると保管中や長期間の使用に際し、
反りやねじれを生じるという欠点があつた。
即ち、上記２者の積層板を建築用下地材として
用いる場合、施工前に反つていると施工時に板同
士の突付部に目隙が生じやすく、又、施工時に反
りがなくても長期間使用すると、室内で発生した
蒸気や結露水による吸湿膨脹と乾燥収縮が繰返さ
れ波打ち現象や釘着部のゆるみが生じる。
特に布クロス張り仕上げの場合、湿気が下地材
に直接影響を及ぼし、波打ち現象が顕著になると
共に、釘着部のゆるみからサビが出て外観を著し
く低下させるという欠点があつた。そこで本考案
は斬かる欠点に鑑み、上記の建築用下地材を基板
とし、合板と木質繊維板を適切な厚さ構成で接着
積層し、且つ、木質繊維板裏面を防湿処理するこ
とにより、反り現象を生じない好適な建築用下地
材の提供を目的とするものである。
この目的を達成する為の本考案の構成は、合板
と該合板に接着された厚みが該合板の２〜６倍の
木質繊維板と該木質繊維板の裏面に貼着された透
湿係数0.07ｇ／m2ｈmmHg以下のシート状物の３
者からなる建築用下地材であつて、裏面からの吸
放湿を極めて少なくするとともに、該合板と該木
質繊維板の吸放湿にによる伸縮を追従させること
による反り現象を生じにくくせしめ、保管中や長
期間の使用に対しても反りやねじれを起さず、釘
着部にゆるみを生じないので美麗なクロス張り仕
上げを可能にしたものである。
以下、本考案を図面に示す実施例に基づいて詳
細に説明する。
図１は本考案の建築用下地材１であり、厚さ２
〜５mmの合板２の裏面に厚さ７〜15mmの木質繊維
板３が合板２と木質繊維板３を厚さ構成比１：２
〜６で接着積層され、木質繊維板３の裏面に防湿
性シート状物４が貼着されて一体化されたもので
ある。
尚、木質繊維板３は軽量で断熱性のあるインシ
ユレーシヨンボードと呼ばれる比重0.35以下のも
のが好ましい。
又、シート状物４はポリエチレンシートやポリ
塩化ビニルシート、ポリプロピレンシート等の合
成樹脂シートの他金属箔シートや塩化ビニルゾル
状物ペーストあるいは塩化ビニリデン樹脂エマル
ジヨンを木質繊維板３の裏面に塗着形成したもの
でもよく透湿係数が0.07ｇ／m2ｈmmHg以下であ
ればよい。即ち該防湿性シート状物は透湿係数
0.8〜1.2ｇ／m2ｈmmHgの合板や木質繊維板に比べ
吸湿が極めて少ないので、本考案の建築用下地材
１は裏面から吸放湿されず、建築用下地材１の表
裏に水蒸気圧差が生じても湿気の透過はほとんど
ない。
従つて、従来の合板と木質繊維板の積層板に比
べ、吸放湿速度が小さく関係湿度の影響を受けに
くいので、湿気による反りや狂いをほとんど生じ
ない。
又、木質繊維板３を合板２の厚さの２〜６倍と
したのは２倍未満や６倍をこえる厚さ構成比で接
着積層し、高湿度条件下に放置した場合、合板２
側の凸反り現象を生じるという実験結果（表１）
が得られたからである。
上述の如く合板２と木質繊維板３の厚さ構成比
を１：２〜６にすると反り現象を生じないという
現象の理由は明らかではないが、たぶん次の様に
考えられる。
本考案建築用下地材１は前述の様にシート状物
４が貼着されているので、吸収湿はほとんど表面
の合板側から行なわれる。
従つて、高湿条件下では該建築用下地材１の材
内の含水率分布は、合板２の表層が高く、木質繊
維板３の裏面シート状物４付近が低くなる。一
方、関係湿度が低いと合板２の表層から放湿しは
じめる。合板、木質繊維板ともに吸放湿により伸
縮するが、気乾状態付近での含水率１％当りの線
膨脹率は合板が0.017％木質繊維板が0.037％であ
り、合板は木質繊維板の約半分であることが知ら
れている。
従つて、本考案建築用下地材１は、外気条件に
対し、合板２が木質繊維板３より早く反応して吸
放湿を始め伸縮しようとするのに対し、合板２と
比べ含水率変化が小さく線膨脹率の大きい木質繊
維板３の伸縮は合板２の伸縮に追従するものと思
われる。
ところが、表１の比較例に示される様に合板２
の木質繊維板３の厚さ構成比を１：1.2とした積
層板を高湿下中に放置すると合板２の割合が大な
ので木質繊維板３が合板２を通して吸放湿を始め
るのに時間を要し、強度の高い合板２が伸張する
のに対し木質繊維板３が追従できないから、合板
２側に凸反りするものと思われる。
一方、表１の比較例２に示される様に合板２と
木質繊維板３の厚さ構成比１：８とした積層板で
は、木質繊維板３が合板２を通して吸放湿する速
度が早くなり木質繊維板３の吸放湿変化が大きく
伸縮しやすい。しかも、強度の高い合板２の構成
比が小さいので木質繊維板３の伸縮に対する拘束
力が小さい。従つて、高湿下に放置すると、木質
繊維板３は合板側で高含水、裏面シート状物側で
低含水状態となり、木質繊維板３自体の合板側の
伸張が大きくなり反り現象を生じ、合板２がそれ
を拘束できないので建築用下地板１全体として合
板２側に凸反りが発生したと思われる。
以上の様に本考案の建築用下地板は合板と木質
繊維板とポリエチレンシート等のシート状物の各
材料の吸放湿特性を生かしてバランス良く接着積
層し、反りを防止したものである。次に、使用例
を図２に示すと、本考案の建築用下地板１を柱５
や間柱４等躯体に裏面シート状物４が当接する様
に釘着又は接着し、クロス６を合板２の表面に貼
着して仕上げるものである。
この時、室内湿度変化があるとクロスを通じて
合板２表面から吸放湿するが、前述の実験で示さ
れた様に、本考案の建築用下地材１は周縁が無拘
束状態でも反りにくい上、躯体に釘着又は接着さ
れているので更に反りは発生しにくくなり、長期
の使用でも良好な外観を保つことができる。
以上に述べた如く、本考案は合板と、該合板に
接着された厚みが該合板の２〜６倍の木質繊維板
と、該木質繊維板の裏面に貼着された透湿係数
0.07ｇ／m2ｈmmHg以下のシート状物の３者から
なる建築用下地材であるので、保管中や長期間の
使用に対しても反りやねじれ、釘着部のゆるみを
生じず美麗なクロス貼り仕上を可能にしたもので
ある。
【表】[Detailed description of the invention] The present invention relates to a laminate suitable as a base material for buildings such as houses, particularly as a base material for interior cloth lining, and provides a base material for construction that has good dimensional stability and does not cause warping. This is what I am trying to do. Conventionally, laminates made by bonding plywood and wood fiberboard have been used as the base material for cloth coverings and decorative laminates as a lightweight construction base material with excellent workability and heat insulation properties. However, the plywood and wood fiberboard mentioned above have moisture absorption and release properties, and have the property of expanding and contracting due to moisture absorption and release.
Since the moisture absorption rate and hygroscopic linear expansion rate of the two materials are different, when the two materials are laminated with adhesive, during storage or long-term use,
It had the disadvantage of warping and twisting. In other words, when using the above two laminates as a base material for construction, if the laminates are warped before construction, gaps are likely to occur at the butting parts of the boards during construction, and even if there is no warping during construction, the laminates will not warp for a long period of time. When used, hygroscopic expansion and drying contraction due to steam and condensed water generated indoors are repeated, resulting in waving and loosening of the nailed parts. Particularly in the case of cloth-covered finishes, moisture directly affects the underlying material, resulting in noticeable waving and rusting from loosened nails, which significantly deteriorates the appearance. Therefore, in view of these drawbacks, the present invention uses the above-mentioned architectural base material as a substrate, adhesively laminates plywood and wood fiberboard with an appropriate thickness configuration, and provides moisture-proof treatment to the back side of the wood fiberboard to prevent warping. The purpose of this invention is to provide a suitable base material for construction that does not cause this phenomenon. The structure of the present invention to achieve this purpose consists of plywood, a wood fiber board with a thickness 2 to 6 times that of the plywood, and a moisture permeability coefficient of 0.07 bonded to the back side of the wood fiber board. g/m 2 hmmHg or less sheet material 3
A construction base material consisting of a material that extremely reduces moisture absorption and release from the back side, and also prevents warping by following the expansion and contraction of the plywood and the wood fiberboard due to moisture absorption and release, and storage. Even after medium or long-term use, it does not warp or twist, and the nailed parts do not loosen, making it possible to create a beautiful cross-covered finish. Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. Figure 1 shows the construction base material 1 of the present invention, with a thickness of 2
A wood fiberboard 3 with a thickness of 7 to 15mm is placed on the back side of a plywood 2 of ~5mm. The plywood 2 and the wood fiberboard 3 are arranged in a thickness composition ratio of 1:2.
- 6 are adhesively laminated, and a moisture-proof sheet material 4 is adhered to the back surface of the wood fiber board 3 to be integrated. The wood fiber board 3 is preferably a lightweight insulation board with a specific gravity of 0.35 or less, which is called an insulation board. The sheet material 4 is formed by applying a synthetic resin sheet such as a polyethylene sheet, a polyvinyl chloride sheet, a polypropylene sheet, a metal foil sheet, a vinyl chloride sol paste, or a vinylidene chloride resin emulsion to the back surface of the wood fiber board 3. Any material may be used as long as the moisture permeability coefficient is 0.07 g/m 2 hmmHg or less. That is, the moisture-proof sheet material has a moisture permeability coefficient of
Since moisture absorption is extremely low compared to plywood or wood fiberboard with a rating of 0.8 to 1.2 g/m 2 hmmHg, the architectural base material 1 of the present invention does not absorb or release moisture from the back side, and there is no water vapor pressure difference between the front and back sides of the architectural base material 1. Even if moisture does occur, there is almost no penetration of moisture. Therefore, compared to conventional laminates of plywood and wood fiberboard, the rate of moisture absorption and release is low and it is less susceptible to the effects of relative humidity, so there is almost no warping or deformation due to moisture. In addition, if the wood fiberboard 3 is made 2 to 6 times the thickness of the plywood 2, if the thickness composition ratio is less than 2 times or more than 6 times, and the wood fiber board 3 is adhesively laminated and left under high humidity conditions, the plywood 2
Experimental results showing that the side convex warpage phenomenon occurs (Table 1)
This is because it was obtained. The reason why no warpage occurs when the thickness composition ratio of the plywood 2 and the wood fiber board 3 is set to 1:2 to 6 as described above is not clear, but it is probably as follows. Since the building material 1 of the present invention has the sheet-like material 4 attached thereto as described above, most of the moisture absorption takes place from the plywood surface side. Therefore, under high humidity conditions, the moisture content distribution within the building material 1 is high in the surface layer of the plywood 2 and low near the back sheet material 4 of the wood fiberboard 3. On the other hand, when the relative humidity is low, moisture begins to radiate from the surface layer of the plywood 2. Both plywood and wood fiberboard expand and contract due to moisture absorption and release, but the linear expansion rate per 1% moisture content in an air-dried state is 0.017% for plywood and 0.037% for wood fiberboard, and plywood is about the same as wood fiberboard. It is known that half Therefore, in the construction base material 1 of the present invention, the plywood 2 reacts to outside air conditions faster than the wood fiberboard 3 and starts absorbing and desorbing moisture and tries to expand and contract, but compared to the plywood 2, the moisture content changes less. It is thought that the expansion and contraction of the wood fiberboard 3, which has a small linear expansion coefficient and a large coefficient of linear expansion, follows the expansion and contraction of the plywood 2. However, as shown in the comparative example in Table 1, plywood 2
When a laminate with a thickness composition ratio of wood fiberboard 3 of 1:1.2 is left in a high humidity environment, since the ratio of plywood 2 is large, it takes time for the wood fiberboard 3 to start absorbing and desorbing moisture through the plywood 2. In short, since the wood fiber board 3 cannot follow the elongation of the high-strength plywood 2, it seems that the plywood 2 is warped in a convex manner. On the other hand, as shown in Comparative Example 2 in Table 1, in the case of a laminate in which the thickness composition ratio of plywood 2 and wood fiberboard 3 is 1:8, the speed at which wood fiberboard 3 absorbs and releases moisture through plywood 2 becomes faster. The moisture absorption and release of the wood fiber board 3 is large and it is easy to expand and contract. Moreover, since the composition ratio of the high-strength plywood 2 is small, the restraining force against expansion and contraction of the wood fiber board 3 is small. Therefore, if left under high humidity, the wood fiberboard 3 will have a high water content on the plywood side and a low water content on the back sheet side, and the elongation of the plywood side of the wood fiberboard 3 itself will increase, causing a warping phenomenon. It is thought that convex warping occurred on the plywood 2 side of the architectural base board 1 as a whole because the plywood 2 could not restrain it. As described above, the architectural baseboard of the present invention takes advantage of the moisture absorbing and desorbing properties of sheet materials such as plywood, wood fiberboard, and polyethylene sheets, and is laminated with adhesive in a well-balanced manner to prevent warping. Next, an example of use is shown in FIG. 2.
The back sheet-like material 4 is nailed or glued so as to be in contact with the frame, studs 4, etc., and the cloth 6 is pasted on the surface of the plywood 2 to finish. At this time, if there is a change in indoor humidity, moisture will be absorbed and released from the surface of the plywood 2 through the cloth, but as shown in the above experiment, the construction base material 1 of the present invention does not warp easily even when the periphery is not constrained, and Since it is nailed or glued to the building frame, warping is less likely to occur, and a good appearance can be maintained even after long-term use. As mentioned above, the present invention consists of plywood, a wood fiber board with a thickness 2 to 6 times that of the plywood, and a moisture permeability coefficient bonded to the back side of the wood fiber board.
Since it is a construction base material consisting of three sheet-like materials with a density of 0.07g/ m2 hmmHg or less, it does not warp, twist, or loosen the nailed parts even during storage or long-term use, making it a beautiful cloth. This allows for a pasted finish. 【table】
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は本考案の建築用下地材を示す斜視図で
あり、第２図は本考案の建築用下地材の施工例を
示す斜視図である。
１……建築用下地材、２……合板、３……木質
繊維板、４……シート状物、５……柱、５′……
間柱、６……クロス、７……外壁構成材。
FIG. 1 is a perspective view showing a construction base material of the present invention, and FIG. 2 is a perspective view showing an example of construction of the construction base material of the present invention. 1... Building material, 2... Plywood, 3... Wood fiberboard, 4... Sheet material, 5... Pillar, 5'...
Stud, 6...Cross, 7...Exterior wall construction material.