【発明の詳細な説明】[Detailed description of the invention]
本発明は、合成樹脂、ゴム等からなる防水層の
少くとも片面に目付80〜800ｇ/m2、透水係数が一
定値以上の緩衝層を接合したことを特徴とする複
合防水シートに関するものである。
合成樹脂、ゴム等の防水層のみからなる従来の
防水シートは、土木分野たとえば貯水池、廃水処
理池の防水膜に使用する際、下地地盤の凹凸のあ
る石類の突出した地表面と直接接触すると、防水
シートが開孔、裂け目等を生じ漏水の原因とな
り、防水機能が発揮できなくなる。特に汎用され
る塩化ビニル防水シートを用いた場合は、低温、
高温の機械特性が常温の機械特性に較べて大幅に
変動し、低温では剛性が高くなり、屈曲抵抗性が
低下する。高温では剛性が低くなり、機械特性の
低下をもたらす。また防水層の相互の接合方法と
して該防水層の端縁部を熱融着または接着剤によ
る方法を用いるが、熱融着法は地表面の凹凸に起
因する融着不完全、接着剤法は接着力が必ずしも
充分でない等により該接合部は剥離、フクレ現象
を生じ易くなる等の根本的欠陥を有していた。
本発明はこれらの問題点を解決し、防水性、熱
安定性、耐久性の優れた複合防水シートを提供す
ることを目的とするものである。
すなわち、本発明の複合防水シートは合成樹
脂、ゴム等からなる防水層の少くとも片面に目付
80／800ｇ/m2、透水係数10-3cm／秒以上の緩衝層
を接合したことを特徴とする複合防水シートであ
つて、凹凸のある地表面やシート上の粗い埋め戻
し土に直接接触しても、その構成要素の一つであ
る緩衝層は適度の強度を有し、柔軟性に優れ下地
地盤への順応性が良いため、本発明の複合防水シ
ートは緩衝層を地表面側又は必要に応じ同層を埋
め戻し土側に接触させることにより、従来の防水
シートの問題点である開孔、裂け目等は完全に解
消される。
また本発明の複合防水シートは、従来の如く防
水層単独に使用したときの欠点である低温、高温
による屈曲性、柔軟性、引張強度、引裂強度、伸
び率等の機械的特性の低下が、耐寒性、耐熱性の
優れた緩衝層が防水層と複合されて大幅に改善さ
れる。
さらに本発明の複合防水シートは、防水層と緩
衝層の複合効果により引張強度、引裂強度等の機
械的強度を従来の防水層単独シートと比較すると
同一強度水準を得る防水層厚は、本発明の複合防
水シートでは、従来品の厚みの２分の１から４分
の１程度に軽減する。このため本発明の複合防水
シートの単位面積当りの重量は、緩衝層を合計し
てもなお防水層単独シートの50％前後に軽減する
省資源効果を発揮する。
本発明の複合防水シートに用いる防水層は高分
子系不透水材料で、加硫型防水材料たとえば、ブ
チルゴム、ポリクロロプレンゴム、エチレンプロ
ピレンゴム、非加硫型防水材料たとえば、ポリイ
ソブチレン、クロロスルホン化ポリエチレン、ポ
リ塩化ビニルおよびその共重合体の防水材料及び
ポリエチレンおよびその共重合体の防水材料等が
用いられるが機能性、経済性等よりポリ塩化ビニ
ル、および酢酸ビニル、エチレン、プロピレンな
どを共重合した塩化ビニル系重合体が好ましい。
ポリ塩化ビニルおよびその共重合体の防水層は、
通常の軟質用樹脂、可塑剤、安定剤、充填剤、着
色剤等よりなる配合物から通常のカレンダー加工
法等により製造する。防水層の厚みは好ましくは
0.2〜５mm、更に好ましくは0.5〜４mm程度であ
る。防水層が５mm以上の厚みでは、格別の防水性
の向上もなく単位面積当りの重量が大きくなり、
取扱いに不便をきたすと同時に経済的に高くなり
好ましくない。また防水層が0.2mm以下の厚みで
は妨水性、耐久性等より好ましくない。
なお、片面のみに緩衝層を接合した防水層より
なる本発明の複合防水シートでは、防水層を上面
にして斜面に敷設する場合、防水層面が平滑であ
ると斜面の勾配が大きい場合、埋め戻し土が斜面
に沿つてすべり、埋め戻し土の維持が困難にな
る。このため、すべり抵抗を大きくするため、通
常は防水層表面に深さが好ましくは0.05〜４mm、
更に好ましくは0.2〜２mm、１cm当りの凹凸組数
が経緯平均0.1〜100組、好ましくは0.5〜50組の
凹凸模様を防水層の機械的強度、防水性が低下し
ない程度に付与するとよい。この模様はまたこの
シートの接着剤による端縁部接合時の接着力向上
の効果もある。
本発明の複合防水シートに用いる緩衝層は具体
的には不織布で、不織布の原料としては、一般に
高分子材料以外を素材としたもの、高分子短繊維
を素材としたもの、高分子長繊維を素材としたも
の等があるが、通常は高密度ポリエチレン、ポリ
プロピレン、ポリ塩化ビニル、ポリ塩化ビニリデ
ン、ポリスチレン、ポリビニルアルコール、ポリ
エステル及びこれらの各種共重合体などが使用で
きる。耐候性、耐水性、耐薬品性、耐微生物性、
耐久性等よりポリエステル、ポリプロピレン等が
好ましい。本発明の複合防水シートに用いる不織
布は、通常の製造方法により繊維状ウエブ、フイ
ラメント積層を組み合わせたもの等の繊維集合
体、すなわち不織布を製造する。
本発明の複合防水シートの緩衝層の目付は80〜
800ｇ/m2、特に100〜500ｇ/m2が好ましく、厚み
は好ましくは0.5〜４mm、更に好ましくは１〜３
mmである。不織布の目付が800ｇ/m2以上では、不
織布の層間剥離を生じ易く、且つ重量が大きくな
り、省資源、経済的にも好ましくない。また、80
ｇ／m2以下では防水層と不織布層の複合効果によ
る機械的強度の増加率は低くなると同時に下地地
盤順応性も低下し使用時防水層の開孔、引裂き等
を生じるようになる。本発明において不織布はま
た地盤上における本発明のシートのすべりを防止
する効果もある。
本発明の複合防水シートの不織布の透水係数
は、水平方向、垂直方向ともに10-3cm／秒以上を
必要とする。透水係数が10-3cm／秒以上であれ
ば、不織布層は垂直方向、水平方向に立体的に極
めて高い通水性、排水性を有し、水を容易に通す
が土粒子をほとんど捕集するため、本発明の複合
防水シートは通常の不織布層を地表面側に接する
ようにして敷設することにより他所の降雨等によ
り地表面に浸出した水のみを滞留させることなく
不織布層を通過排出せしめ、土粒子を移動させな
いため複合防水シート敷設下部の地盤は極めて安
定する。また水平方向に排水効果があるため軟弱
地盤、含水地盤に用いると圧密促進し、地盤の軟
弱性を改良する効果を有する。しかるに不織布の
透水係数が10-3cm／秒以下では通水性、排水性の
低下により不織布層下部の滞水量は増加し、被圧
水の増大により複合防水シートの浮き上りを生じ
好ましくない。透水係数が10-3cm／sec以上なら
また不織布層を上側にして用いた場合は、防水層
上の水を滞水を生じずにかつ土粒子の移動を伴な
わずに分散せしめる効果もある。不織布層は防水
層の少くとも片面に接合するが、前記の如く防水
層の片面に不織布を接合した複合防水シートは、
防水層を上面にして斜面に敷設する場合、埋め戻
し土のすべり抵抗を大きくするため、防水層表面
に凹凸模様を付与することが好ましいが、防水層
を下面とする場合や防水層の両面に不織布を接合
した複合防水シートの場合は、斜面に敷設する場
合、不織布の多孔性面の大きなすべり抵抗により
埋め戻し土を容易に捕促するためこの点では上面
側防水層面の凹凸模様の付与を必ずしも必要とし
ない。
本発明の複合防水シートに用いる防水層と緩衝
層の接合は熱融着法または接着剤を用いた接着法
がとられる。熱融着法による場合は、防水層の軟
化点または溶融温度は緩衝層すなわち不織布層の
軟化点または溶融温度より低いのが好ましく、た
とえば防水層にポリ塩化ビニルおよびその共重合
体、不織布層にポリエステル、ポリプロピレンを
用いるのが好ましい。接着法を使用する際、防水
層にポリ塩化ビニル、不織布層にポリエステル、
またはポリプロピレンの構成では、接着剤は一般
に塩化ビニル／酢酸ビニルの共重合体を用いると
よいが接着強度が本発明の複合防水シートの機能
を発揮に充分ならば接着剤の選択は任意である。
本発明の複合防水シートの相互の接続法は、通
常該複合防水シートの端縁ラツプ面に接着剤を用
いる接着法、または熱融着法がとられる。前記接
着法の接着剤の塗布面は複合防水シートの緩衝層
が好ましく、緩衝層に塗布された接着剤は、緩衝
層の空隙中に充分浸透し緩衝層に防水性を与え、
複合防水シートと強固に一体化する。該シートの
接続法としては、たとえば防水層の両面に不織布
を接合した複合防水シートの該シート端縁相互を
突き合せ、あらたに防水層の片面または両面に不
織布を接合した複合防水シートを20〜30cmの幅に
切断したラツプシートの緩衝層に接着剤を充分塗
布した後、該ラツプシートの長手方向の中心線を
前記突き合せ部の上においた後貼合せる。なお貼
合せ面は接着剤の接着効果を充分発揮させるため
と通水性、防水性より複合防水シートの緩衝層と
ラツプシートの充分な量の接着剤を塗布した緩衝
層を貼合せる方法が好ましい。
また複合防水シートの端縁において、防水層の
幅を緩衝層の幅より小さくすることにより、複合
防水シートの接続法として、端縁相互の緩衝層の
ラツプ面に接着剤を塗布して貼合せる方法または
互いに接続される両接続部の一方の端縁に突き出
た緩衝層を有する複合防水シートを用い該緩衝層
に接着剤を塗布し他方の複合防水シートの不織布
層と貼合せる方法もとられる。なお一般に前記の
接合された複合防水シートの緩衝層は通水性、防
水性よりいずれも地表面側におく。熱融着法とし
ては、例えば防水層の片面に緩衝層を接合した複
合防水シートにおいて、緩衝層を防水層の下面に
してシート端縁相互を突き合せ、あらたに20〜30
cm幅に切断した防水層単独のラツプシートを該複
合防水シートの上面の防水層側にして該ラツプシ
ートの長手方向の中心線を突き合せ部の上におい
た後、防水層を熱融着して一体化させ接続する方
法が好ましい。上記の接着法及び熱融着法を用い
た複合防水シートの接合部は引張強度及び防水性
は充分実用的であり、また従来の塩化ビニルシー
ト単独に較べて優れている。さらに上記した接着
法と熱融着法を併用することも差支えない。本発
明の複合防水シートの接続法は、本発明の複合防
水シートの機能をそこなわなければ、上記以外の
種々の組合せは任意にとつて差支えない。
上記接着法に用いる接着剤は通常のウレタン樹
脂、エポキシ樹脂、ポリサルフアイド、クロロプ
レンゴム、クロロスルホン化ポリエチレン、アク
リルエマルジヨン、スチレンブタジエンゴム、ポ
リ酢酸ビニル、ポリ塩化ビニル等が用いられる
が、長期耐久性、防水性、施工性よりウレタン樹
脂、エポキシ樹脂、ポリサルフアイドが好まし
い。
本発明の複合防水シートは土木、たとえば産業
廃棄物処理池防水、防波堤侵蝕防止、防潮堤護岸
工事、貯水池、潅漑、落石防止、植生、鉄道路盤
噴泥防止、養魚池等に好適に用いられるので産業
上利する所大なるものである。
次に実施例によりこの発明を具体的に説明す
る。なお透水係数はJIS A1218土の透水試験方法
に準じて測定した。
実施例 １
ポリエステルの長繊維からなる不織布層（厚さ
1.5mm、目付160ｇ/m2、透水係数５×10-2cm／
sec）を両面に深さ0.1mmの凹凸模様を平均１cm当
り20組付与した厚さ１mmのポリ塩化ビニルシート
の片面に、また同様の模様を付した厚さ0.5mmの
ポリ塩化ビニルシートの両面に、各々塩化ビニ
ル／酢酸ビニル共重合体の接着剤を用いて接合し
て複合防水シートを得た。
該シートの物性として引張強さ、伸び率、引裂
強さをJIS A6009基布その他を積層した合成高分
子ルーフイングに準じて求め表１に示した。表１
より明らかなごとく、単位面積当りの重量では、
本発明の複合防水シートは、従来の塩ビシート
（ポリ塩化ビニルシート）の37％、56％に重量は
軽減し、しかも引張強さ、引裂強さの20℃の値は
塩ビシートを上まわる。また低温測定値は、引張
試験では、複合防水シートは常温数値の145〜154
％におさまるが、塩ビシートは、260〜270％と大
幅に上昇している。
さらに引裂試験では、複合防水シートは常温数
値の125〜176％におさまるが、塩ビシートは、
285〜274％と変化し、伸び率も複合防水シートは
常温数値の27〜44％の範囲に対して、塩ビシート
は６〜８％と極端に低下する。高温測定値でも引
裂試験では、複合防水シートは常温数値とほぼ同
水準にあるが、塩ビシートは常温数値の50％も低
下し、引張試験でも複合防水シートと塩ビシート
の差は明らかである。
以上により本発明の複合防水シートは、従来の
塩ビシートに較べて優れた熱安定性を有すること
は明らかである。
実施例 ２
ポリプロピレンの長繊維からなる不織布（厚さ
３mm、目付300ｇ/m2、透水係数２×10-3cm／sec）
を、実施例１と同様の模様を付した厚さ1.5mmの
ポリ塩化ビニルシートの片面に塩化ビニル／酢酸
ビニル共重合体の接着剤を用いて接続して複合防
水シートを得る際、該複合防水シートの端縁は不
織布層のみ100mm出しておき、このシート２枚の
一方の端縁につき該不織布層にウレタンエラスト
マー（パラツクスＥ―三井東圧化学製）を約200
ｇ／cm2塗布し、両シートの防水層が同じ側となる
様端縁相互を貼合せてから、温度20℃で７日間養
生し、接合部の引張強度を測定した(1)。また２枚
の複合防水シートの端縁相互を両シートの防水層
が同じ側になる様突き合せ、該突き合せ部にあら
たに20cm幅に切断した複合防水シート（ラツプシ
ート）の不織布層に上記ウレタンエラストマー
（パラツクスＥ）を同様に塗布して、該ラツプシ
ートの長手方向の中心線を上記突き合せ部の緩衝
層の上に防水層／緩衝層の位置関係が両シートと
同じくなるようおいて貼合せ、20℃で７日間養生
した後、接合部の温度20℃の引張強度を測定した
(2)。
また上記とは逆に端縁部で防水層が10cm出てい
る本発明の防水シートを作り、上記(1)又は(2)に準
じる接合を行い同様の試験を行つた〔夫々(3)又は
(4)〕。但し(4)ではラツプシートの防水層側にウレ
タンエラストマーを塗布した。
更に、上記と同様にして今度は片側の端縁では
不織布層が100mm長く、他の端縁では防水層が100
mm長い防水シート２枚を用い防水層が同じ側にな
るようにした両者の、突出した防水層と不織布層
が丁度重なり合うような配置で、不織布側にエラ
ストマーを塗布して同様に接合を行い試験に供し
た(5)。
〔これらの方法及び下記(7)の方法に於ては、接
着剤が不織布層に浸透硬化して防水層となるので
両シートの防水性は接合部に於ても充分確保され
る。(5)の方法の場合一方のシートは端縁で不織布
層が突出し、他のシートでは防水層が突出したも
のでも同様の接合が出来るが、１形状ですむ上記
(5)の方法がすぐれている。なお(3)の方法は、実用
上一般に接合部に別途保護を要することがあるの
で余り採用されない。また不織布層を両面に有す
る本発明の防水シートでは、同様にして３層のな
す端縁が２段状、３段状、凹状、凸状となつたも
のを一般には雌雄かん合状に適宜組合せ、ラツプ
シートを用いず又は用いて接着剤法により接合す
ることができる。〕
次に、上記同様に防水層の片側に不織布層を接
合した防水シートで端縁に於ても両層を有するも
の２枚の端縁を両防水層が同じ側となるよう突き
合せ、(2)と同様のラツプシートの防水層側に同様
に接着剤を塗布して、突き合せ部の防水層側に同
様に接着した(6)。
また、上記(6)に用いたと同様のシート２枚の端
縁が防水層を同じ側として10cmの幅で重なり合う
ように、他のシートの防水層と接して重なる方の
不織布層部分に同様に接着剤を塗布して接着した
(7)。
比較例として従来の両面平滑な厚さ２mmのポリ
塩化ビニルシートを、同様の接着方法により端縁
を重ね合せた接合（）及び同シートを切断して
得たラツプシートを用いた接合（）を行い同様
の試験を行つた。この結果、従来の両面平滑なポ
リ塩化ビニルシートを接合した、に較べて、
本発明の複合防水シートを防水層で接合させた引
張強度は、防水層の凹凸部に接着剤が充填され、
投錨効果を発揮するため、はるかに大きくなる。
また参考の為本発明のシート及び比較例のシー
トの接合部なしの強度も測定した〔夫々（０）及
び（）〕。
各測定結果は表２に示した。
実施例 ３
実施例１の片面不織布複合防水シートの不織布
層の透水係数を表３に示すように変えた複合防水
シートにおいて、防水層を上面（不織布層下面）
にして直径50cmのシートに裁断した。
該各シートを不織布層を下にして透水係数10-7
cm／秒の不透水性粘土地盤の上に設置した後、該
複合防水シートの上面のポリ塩化ビニルシート層
上面から下面まで貫通して、外径12mmの孔を開
け、該孔にガラス管（内径10mm、外径12mm、高さ
105cm）を挿入し、挿入ガラス管とポリ塩化ビニ
ルシートを接着剤で完全水密接合してからガラス
管中に水を満たし水頭差100cmを維持するようガ
ラス管先端より注入し、30分後の複合防水シート
の透水性と浮き上りを観察した。
実施例 ４
実施例１の片面不織布複合防水シートの不織布
層の目付を表―４に示すように変えた複合防水シ
ートにおいて、防水層を上面（不織布層を下面）
にして、直径22cmのシートに裁断した。
直径20cm、高さ20cmの下部が円筒形状、上部が
円錐形状の耐圧容器で容器底面より高さ10cmで上
下が分割され、分割部がフランジ締結装置を備え
た容器の円筒部に小石（20〜40mm径）を充填した
後、上記シートを防水層を上にして小石の上に設
置し容器上部を締結してから、容器上部中央の直
径10mmの孔より容器中のシート面に、圧力13Kg／
cm2の圧縮空気による圧力を８日間かけ、シートの
開孔、裂け目等を観察した（小石パンチングテス
ト）。
また、上記不織布層の目付を調整した複合防水
シートを、幅30mm、長さ100mmの長方形に切り取
り、得た試験片の長さ30mmの方の１辺で両層間に
ナイフを入れ長さ方向に10mm切開し、切開された
不織布層端に２Kgの荷重をかけて180゜ピーリング
テストを施した。結果を表４に示す。
The present invention relates to a composite waterproof sheet characterized by having a waterproof layer made of synthetic resin, rubber, etc., and a buffer layer having a basis weight of 80 to 800 g/m 2 and a water permeability above a certain value bonded to at least one side of the waterproof layer. . Conventional waterproof sheets consisting only of waterproof layers made of synthetic resin, rubber, etc., when used in the civil engineering field, for example, as waterproof membranes for reservoirs and wastewater treatment ponds, do not come into direct contact with the protruding ground surface of uneven stones on the underlying ground. , the waterproof sheet may develop holes, tears, etc., causing water leakage, making it unable to perform its waterproof function. In particular, when using a commonly used PVC waterproof sheet, low temperatures,
Mechanical properties at high temperatures vary significantly compared to those at room temperature, and at low temperatures stiffness increases and bending resistance decreases. At high temperatures, the stiffness decreases, resulting in a decrease in mechanical properties. In addition, as a method of joining waterproof layers together, the edges of the waterproof layers are bonded by heat or adhesive. Due to insufficient adhesive strength, the bonded portion has fundamental defects such as peeling and blistering. The object of the present invention is to solve these problems and provide a composite waterproof sheet with excellent waterproof properties, thermal stability, and durability. That is, the composite waterproof sheet of the present invention has a waterproof layer made of synthetic resin, rubber, etc. on at least one side.
A composite waterproof sheet characterized by bonding a buffer layer of 80/800 g/m 2 and a permeability coefficient of 10 -3 cm/sec or more, and is in direct contact with uneven ground surfaces or coarse backfill soil on the sheet. However, the buffer layer, which is one of its constituent elements, has moderate strength, excellent flexibility, and good adaptability to the underlying ground. By bringing the same layer into contact with backfilling soil as necessary, problems with conventional waterproof sheets, such as holes and tears, can be completely eliminated. In addition, the composite waterproof sheet of the present invention does not suffer from the deterioration of mechanical properties such as flexibility, flexibility, tensile strength, tear strength, and elongation due to low and high temperatures, which is a disadvantage when used as a waterproof layer alone as in the past. A buffer layer with excellent cold and heat resistance is combined with a waterproof layer, resulting in significant improvements. Furthermore, when the composite waterproof sheet of the present invention has mechanical strengths such as tensile strength and tear strength due to the combined effect of the waterproof layer and the buffer layer, when compared with a conventional waterproof layer single sheet, the waterproof layer thickness that achieves the same strength level is determined by the present invention. With this composite waterproof sheet, the thickness is reduced to about 1/2 to 1/4 of the thickness of conventional products. Therefore, the weight per unit area of the composite waterproof sheet of the present invention is reduced to about 50% of that of a sheet with only a waterproof layer, even when the buffer layers are added together, so it exhibits a resource-saving effect. The waterproof layer used in the composite waterproof sheet of the present invention is made of a polymer-based water-impermeable material, such as vulcanized waterproof materials such as butyl rubber, polychloroprene rubber, ethylene propylene rubber, non-vulcanized waterproof materials such as polyisobutylene, chlorosulfonated Waterproof materials made of polyethylene, polyvinyl chloride, and their copolymers, and waterproof materials made of polyethylene and their copolymers are used, but due to functionality, economy, etc., polyvinyl chloride, vinyl acetate, ethylene, propylene, etc. are copolymerized. Polyvinyl chloride polymers are preferred.
The waterproof layer of polyvinyl chloride and its copolymers is
It is manufactured by a conventional calendering method from a compound consisting of a conventional softening resin, a plasticizer, a stabilizer, a filler, a coloring agent, etc. The thickness of the waterproof layer is preferably
It is about 0.2 to 5 mm, more preferably about 0.5 to 4 mm. If the thickness of the waterproof layer is 5mm or more, the weight per unit area will increase without any particular improvement in waterproofness.
This is not desirable as it is inconvenient to handle and is also economically expensive. Further, a waterproof layer having a thickness of 0.2 mm or less is not preferable due to water repellency, durability, etc. In addition, when the composite waterproof sheet of the present invention consisting of a waterproof layer with a buffer layer bonded to only one side is laid on a slope with the waterproof layer on the top side, if the waterproof layer surface is smooth and the slope slope is large, backfilling is required. The soil slides along the slope, making it difficult to maintain backfill soil. Therefore, in order to increase the slip resistance, the surface of the waterproof layer usually has a depth of preferably 0.05 to 4 mm.
More preferably, the uneven pattern is 0.2 to 2 mm, and the number of uneven patterns per cm is 0.1 to 100, preferably 0.5 to 50, to an extent that does not reduce the mechanical strength and waterproof property of the waterproof layer. This pattern also has the effect of improving the adhesive force when joining the edges of this sheet with an adhesive. The buffer layer used in the composite waterproof sheet of the present invention is specifically a nonwoven fabric, and the raw materials for the nonwoven fabric are generally those made of materials other than polymeric materials, those made of short polymeric fibers, and those made of long polymeric fibers. There are various materials that can be used, but usually high-density polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyester, and various copolymers thereof can be used. Weather resistance, water resistance, chemical resistance, microbial resistance,
Polyester, polypropylene, etc. are preferable in terms of durability and the like. The nonwoven fabric used in the composite waterproof sheet of the present invention is a fiber aggregate such as a combination of a fibrous web and filament lamination, that is, a nonwoven fabric, by a conventional manufacturing method. The basis weight of the buffer layer of the composite waterproof sheet of the present invention is 80~
800 g/m 2 , especially 100 to 500 g/m 2 is preferable, and the thickness is preferably 0.5 to 4 mm, more preferably 1 to 3 mm.
mm. If the basis weight of the nonwoven fabric is 800 g/m 2 or more, delamination of the nonwoven fabric tends to occur, and the weight becomes large, which is not preferable in terms of resource saving or economy. Also, 80
If it is less than g/m 2 , the rate of increase in mechanical strength due to the combined effect of the waterproof layer and the non-woven fabric layer will be low, and at the same time, the conformability to the underlying ground will also decrease, resulting in holes and tears in the waterproof layer during use. In the present invention, the nonwoven fabric also has the effect of preventing the sheet of the present invention from slipping on the ground. The water permeability coefficient of the nonwoven fabric of the composite waterproof sheet of the present invention needs to be 10 -3 cm/sec or more in both the horizontal and vertical directions. If the permeability coefficient is 10 -3 cm/sec or higher, the nonwoven fabric layer has extremely high water permeability and drainage in both the vertical and horizontal directions, allowing water to pass through easily but capturing most of the soil particles. Therefore, in the composite waterproof sheet of the present invention, by laying a normal non-woven fabric layer in contact with the ground surface, only water that has seeped onto the ground surface due to rainfall in other places can be discharged through the non-woven fabric layer without being retained. Since soil particles are not moved, the ground beneath the composite tarpaulin sheet is extremely stable. Also, since it has a drainage effect in the horizontal direction, when used on soft or water-containing ground, it promotes consolidation and has the effect of improving the softness of the ground. However, if the water permeability coefficient of the nonwoven fabric is less than 10 -3 cm/sec, the water permeability and drainage performance will decrease, resulting in an increase in the amount of water stagnant at the bottom of the nonwoven fabric layer, which is undesirable because the increased pressurized water will cause the composite waterproof sheet to rise. If the water permeability coefficient is 10 -3 cm/sec or more, and if the nonwoven fabric layer is used on the upper side, it has the effect of dispersing water on the waterproof layer without causing water stagnation or movement of soil particles. . The nonwoven fabric layer is bonded to at least one side of the waterproof layer, but the composite waterproof sheet in which the nonwoven fabric is bonded to one side of the waterproof layer as described above is
When laying the waterproof layer on a slope with the waterproof layer facing up, it is preferable to add an uneven pattern to the surface of the waterproof layer in order to increase the sliding resistance of the backfill soil. In the case of a composite waterproof sheet made of bonded non-woven fabric, when it is laid on a slope, the porous surface of the non-woven fabric can easily catch backfilling soil due to its large slip resistance. Not necessarily necessary. The waterproof layer and the buffer layer used in the composite waterproof sheet of the present invention are bonded by a heat fusion method or an adhesive method using an adhesive. When using the heat fusion method, it is preferable that the softening point or melting temperature of the waterproof layer is lower than that of the buffer layer, that is, the nonwoven fabric layer. It is preferable to use polyester or polypropylene. When using the adhesive method, the waterproof layer is made of polyvinyl chloride, the non-woven layer is made of polyester,
Alternatively, in the case of a polypropylene composition, it is generally preferable to use a copolymer of vinyl chloride/vinyl acetate as the adhesive, but the adhesive can be selected arbitrarily as long as the adhesive strength is sufficient for the composite waterproof sheet of the present invention to perform its functions. The method of interconnecting the composite waterproof sheets of the present invention is usually an adhesive method using an adhesive on the edge lap surface of the composite waterproof sheet, or a heat fusion method. The surface on which the adhesive of the adhesive method is applied is preferably a buffer layer of a composite waterproof sheet, and the adhesive applied to the buffer layer sufficiently penetrates into the voids of the buffer layer and imparts waterproof properties to the buffer layer.
Strongly integrated with the composite tarpaulin sheet. The sheet can be connected, for example, by butting the sheet edges of a composite waterproof sheet in which nonwoven fabric is bonded to both sides of the waterproof layer, and then attaching a new composite waterproof sheet in which nonwoven fabric is bonded to one or both sides of the waterproof layer. After sufficiently applying adhesive to the buffer layer of a wrap sheet cut into a width of 30 cm, the longitudinal center line of the wrap sheet is placed on the abutting portion and then laminated. In order to fully exhibit the adhesion effect of the adhesive and to ensure water permeability and waterproof properties, it is preferable that the bonding surface be bonded with the buffer layer of the composite waterproof sheet and the buffer layer coated with a sufficient amount of adhesive of the wrap sheet. In addition, by making the width of the waterproof layer smaller than the width of the buffer layer at the edges of the composite tarpaulin sheet, a method of connecting the composite tarpaulin sheet is to apply adhesive to the lap surfaces of the buffer layer between the edges and stick them together. Another method is to use a composite waterproof sheet that has a buffer layer protruding from one edge of both joints that are connected to each other, apply an adhesive to the buffer layer, and bond it to the nonwoven fabric layer of the other composite waterproof sheet. . Generally, the buffer layer of the bonded composite waterproof sheet is placed on the ground surface side for reasons of water permeability and waterproof properties. As a heat fusion method, for example, in a composite waterproof sheet in which a buffer layer is bonded to one side of a waterproof layer, the buffer layer is placed on the bottom side of the waterproof layer, and the edges of the sheet are butted against each other, and a new 20 to 30
A lap sheet with a single waterproof layer cut into cm width is placed on the waterproof layer side of the upper surface of the composite waterproof sheet, and the longitudinal center line of the wrap sheet is placed on the butt part, and then the waterproof layer is heat fused and integrated. It is preferable to connect the The joints of composite waterproof sheets made using the above-mentioned adhesion method and heat fusion method have sufficient tensile strength and waterproof properties for practical use, and are superior to conventional vinyl chloride sheets alone. Furthermore, there is no problem in using the above-described adhesion method and heat fusion method together. The method for connecting the composite waterproof sheet of the present invention may be any combination other than the above, as long as the function of the composite waterproof sheet of the present invention is not impaired. The adhesive used in the above bonding method is usually urethane resin, epoxy resin, polysulfide, chloroprene rubber, chlorosulfonated polyethylene, acrylic emulsion, styrene-butadiene rubber, polyvinyl acetate, polyvinyl chloride, etc., but they have long-term durability. , urethane resin, epoxy resin, and polysulfide are preferable in terms of waterproofness and workability. The composite waterproof sheet of the present invention can be suitably used in civil engineering, such as industrial waste treatment pond waterproofing, breakwater erosion prevention, seawall protection work, reservoirs, irrigation, rockfall prevention, vegetation, railway deck mud prevention, fish ponds, etc. This is of great industrial benefit. Next, the present invention will be specifically explained with reference to Examples. The permeability coefficient was measured according to JIS A1218 soil permeability test method. Example 1 A nonwoven fabric layer (thickness:
1.5mm, weight 160g/m 2 , coefficient of permeability 5×10 -2 cm/
sec) on one side of a 1 mm thick polyvinyl chloride sheet with an uneven pattern of 0.1 mm depth on both sides, 20 pairs per 1 cm on average, and on both sides of a 0.5 mm thick polyvinyl chloride sheet with the same pattern. Then, a composite waterproof sheet was obtained by bonding them together using a vinyl chloride/vinyl acetate copolymer adhesive. The physical properties of the sheet, such as tensile strength, elongation, and tear strength, were determined in accordance with JIS A6009 for synthetic polymer roofing laminated with base fabric and others, and are shown in Table 1. Table 1
As is clearer, the weight per unit area is
The composite waterproof sheet of the present invention has a weight reduction of 37% and 56% compared to conventional PVC sheets (polyvinyl chloride sheets), and its tensile strength and tear strength at 20°C exceed those of PVC sheets. In addition, the low temperature measurement value in the tensile test was 145 to 154 of the normal temperature value for the composite waterproof sheet.
%, but that of PVC sheets has increased significantly to 260-270%. Furthermore, in the tear test, the composite waterproof sheet was 125 to 176% of the normal temperature value, but the PVC sheet was
The elongation rate varies from 285 to 274%, and the elongation rate for the composite waterproof sheet is in the range of 27 to 44% at room temperature, whereas the elongation rate for the PVC sheet is extremely low at 6 to 8%. Even in the high-temperature tear test, the composite tarpaulin sheet's value is almost at the same level as the room temperature value, but the PVC sheet's value is 50% lower than the room temperature value, and the difference between the composite tarpaulin sheet and the PVC sheet is clear even in the tensile test. From the above, it is clear that the composite waterproof sheet of the present invention has superior thermal stability compared to conventional PVC sheets. Example 2 Non-woven fabric made of polypropylene long fibers (thickness 3 mm, basis weight 300 g/m 2 , water permeability coefficient 2×10 -3 cm/sec)
was attached to one side of a 1.5 mm thick polyvinyl chloride sheet with the same pattern as in Example 1 using a vinyl chloride/vinyl acetate copolymer adhesive to obtain a composite waterproof sheet. Leave 100 mm of the non-woven fabric layer at the edge of the waterproof sheet, and apply approximately 200 mm of urethane elastomer (Parax E - manufactured by Mitsui Toatsu Chemicals) to the non-woven fabric layer on one edge of the two sheets.
g/cm 2 was applied, and the edges of both sheets were pasted together so that the waterproof layers were on the same side. After curing at a temperature of 20°C for 7 days, the tensile strength of the joint was measured (1). In addition, the edges of the two composite waterproof sheets are butted together so that the waterproof layers of both sheets are on the same side, and the above-mentioned urethane is added to the nonwoven fabric layer of the composite waterproof sheet (lap sheet) cut into a new 20 cm width at the butt part. Apply elastomer (Parax E) in the same way, and laminate the wrap sheet with the longitudinal center line on top of the buffer layer at the abutting part so that the positional relationship of the waterproof layer/buffer layer is the same as that of both sheets. After curing at 20℃ for 7 days, the tensile strength of the joint at a temperature of 20℃ was measured.
(2). In addition, contrary to the above, a waterproof sheet of the present invention with a waterproof layer protruding by 10 cm at the edge was made, and the same tests were conducted by joining according to (1) or (2) above [(3) or (2), respectively.
(Four)〕. However, in (4), urethane elastomer was applied to the waterproof layer side of the lap sheet. Furthermore, in the same way as above, the nonwoven fabric layer is 100 mm longer on one edge, and the waterproof layer is 100 mm longer on the other edge.
Using two mm long waterproof sheets, the waterproof layers are on the same side, and the protruding waterproof layer and non-woven fabric layer are exactly overlapped, and the non-woven fabric side is coated with elastomer and bonded in the same way. (5). [In these methods and the method (7) below, the adhesive penetrates into the nonwoven fabric layer and hardens to form a waterproof layer, so the waterproofness of both sheets is sufficiently ensured even at the joint. In the case of method (5), the nonwoven fabric layer protrudes from the edge of one sheet, and the waterproof layer protrudes from the other sheet, and the same bonding can be achieved, but the above method requires only one shape.
Method (5) is superior. Note that method (3) is not often adopted in practice because it may require additional protection for the joint. In addition, in the waterproof sheet of the present invention having non-woven fabric layers on both sides, the edge edges of the three layers are generally two-tiered, three-tiered, concave, and convex, and are generally combined as appropriate in a male-female interlocking pattern. , and can be joined by an adhesive method with or without a wrap sheet. ] Next, in the same way as above, a waterproof sheet with a non-woven fabric layer bonded to one side of the waterproof layer, which also has both layers on the edge, butt the edges of two sheets so that both waterproof layers are on the same side, ( Adhesive was similarly applied to the waterproof layer side of the lap sheet similar to 2), and it was adhered to the waterproof layer side of the abutted portion in the same manner (6). In addition, apply the same method to the nonwoven fabric layer of the other sheet that contacts and overlaps the waterproof layer so that the edges of the two sheets similar to those used in (6) above overlap with a width of 10 cm with the waterproof layer on the same side. applied adhesive and adhered
(7). As comparative examples, conventional polyvinyl chloride sheets with a thickness of 2 mm and smooth on both sides were bonded by overlapping their edges using the same bonding method (), and bonding was performed using a wrap sheet obtained by cutting the same sheets (). A similar test was conducted. As a result, compared to the conventional method of joining smooth double-sided polyvinyl chloride sheets,
The tensile strength of the composite waterproof sheet of the present invention bonded with a waterproof layer is determined by filling the uneven parts of the waterproof layer with adhesive.
It becomes much larger because it exerts an anchoring effect. For reference, the strengths of the sheets of the present invention and the sheets of comparative examples without joints were also measured [(0) and (), respectively]. The measurement results are shown in Table 2. Example 3 In the composite waterproof sheet in which the water permeability coefficient of the nonwoven fabric layer of the single-sided nonwoven fabric composite waterproof sheet of Example 1 was changed as shown in Table 3, the waterproof layer was placed on the upper surface (lower surface of the nonwoven fabric layer).
It was then cut into sheets with a diameter of 50 cm. Each sheet is placed with the nonwoven fabric layer facing down and has a water permeability coefficient of 10 -7.
cm/sec. After installation on impermeable clay ground, a hole with an outer diameter of 12 mm is drilled through the polyvinyl chloride sheet layer on the top surface of the composite waterproof sheet from the top surface to the bottom surface, and a glass tube ( Inner diameter 10mm, outer diameter 12mm, height
105cm), completely water-tightly bond the inserted glass tube and the polyvinyl chloride sheet with adhesive, then fill the glass tube with water and inject it from the tip of the glass tube to maintain a water head difference of 100cm. After 30 minutes, the composite The water permeability and lifting of the waterproof sheet were observed. Example 4 In a composite waterproof sheet in which the fabric weight of the nonwoven fabric layer of the single-sided nonwoven fabric composite waterproof sheet of Example 1 was changed as shown in Table 4, the waterproof layer was placed on the top surface (the nonwoven fabric layer was placed on the bottom surface).
and cut it into sheets with a diameter of 22 cm. It is a pressure-resistant container with a diameter of 20 cm and a height of 20 cm, with a cylindrical lower part and a conical upper part.It is divided into upper and lower parts at a height of 10 cm from the bottom of the container. 40mm diameter), place the sheet on top of the pebbles with the waterproof layer facing up, fasten the top of the container, and then apply a pressure of 13kg/kg to the sheet surface in the container through a 10mm diameter hole in the center of the top of the container.
Compressed air pressure of cm 2 was applied for 8 days, and the sheet was observed for holes, tears, etc. (pebble punching test). In addition, the composite waterproof sheet with the adjusted nonwoven fabric layer weight was cut into a rectangle with a width of 30 mm and a length of 100 mm, and a knife was inserted between both layers on one side of the 30 mm length of the obtained test piece in the length direction. A 10 mm incision was made, and a 180° peeling test was performed by applying a load of 2 kg to the edge of the incised nonwoven fabric layer. The results are shown in Table 4.
【表】【table】
【表】
(注) 無処理；加熱しない試料で測定
〓内数値；20℃測定値100を基準とする
[Table] (Note) Untreated: Measured with a sample that is not heated. Values in 〓: Based on the measured value of 100 at 20℃
【表】【table】
【表】【table】
【表】【table】
【表】【table】