【発明の詳細な説明】[Detailed description of the invention]
本発明は表面硬化化粧板の製造において、表層
部の表面硬度が大きく、かつ耐クラツク性にすぐ
れる化粧板の製造方法に関する。
従来、化粧板の表面硬度や耐摩耗性、寸法安定
性などを向上させるため、化粧用スライス単板に
熱硬化性樹脂を減圧又は加圧下で含浸させ、加熱
して硬化させる、いわゆるWPC（Wood Plastic
Combination）処理が施される。化粧用単板とし
て松や栂を使用する場合はこのWPC処理によつ
て、より美麗な木目を形成することができる。と
ころが化粧用転板として檜や杉のように白色系の
木肌を有する木材の場合には、このWPC処理に
より木肌の黄色味が強くなつたり、黄褐色の濡れ
色を呈すようになり、商品価値を著しく低下させ
るという欠点がある。
また一方、化粧単板上に熱硬化性樹脂含浸紙を
オーバレイする方法もある。この方法では意匠的
には満足するものが得られるものの、表面硬度は
WPC処理によるものより劣り、また耐クラツク
性も不充分である。一般に耐クラツク性と表面硬
度とは相反する性質であるため、単に一枚の樹脂
含浸紙を化粧単板上に熱圧成型する従来のオーバ
レイ法では耐クラツク性と表面硬度の両性能を同
時に満足する化粧板を製造することは困難であ
る。
本発明は上記オーバレイによる化粧板の製造方
法において、硬化後の性状の異なる複数の含浸紙
を化粧単板上に積層圧着することにより、耐クラ
ツク性および表面硬度を同時に高めた化粧板を製
造するものであつて、その構成は、基板上に接着
剤を介して貼着した化粧単板上に、クロス方向の
伸びが樹脂硬化後20％以上ある熱硬化性樹脂含浸
紙を重ね、更にこの上に同様の伸びが10％以下で
ある熱硬化性樹脂含浸紙を重ね、これらを同時に
熱圧成型することを特徴とする。
以下に本発明を実施例と共に詳細に説明する。
先ず本発明に用いられる化粧単板としては特に
杉、檜等白色系木肌を有する化粧単板の他に、木
材中に樹脂硬化阻害物質等が存在するためWPC
処理を行えない樹種例えばサワラ、杉のような針
葉樹又は欅のような広葉樹の化粧単板が使用され
る。これ等の化粧単板は常法により基板合板上へ
接着される。接着剤としては熱硬化性樹脂接着剤
および熱可塑性樹脂接着剤から成る混合接着剤例
えば変性合成ゴムラテツクスとアミノ樹脂の混合
物、又は変性ゴムラテツクス等が好適である。化
粧単板上に熱圧接着される熱硬化性樹脂含浸紙は
薄葉紙、不織布、化繊紙等にメラミン樹脂、不飽
和ポリエステル樹脂、アクリル樹脂、ジアリルフ
タレート樹脂等を含浸半硬化させたものが用いら
れる。ここで下層用の含浸紙としては樹脂硬化後
のクロス方向の伸び率が20％以上のものを用い、
また上層用の含浸紙としては樹脂硬化後のクロス
方向の伸び率が10％以下のものを用いる。ここで
クロス方向の伸びとは含浸紙の繊維が配列される
方向において、その繊維の長手方向に対して直角
方向の伸びを云う。一般に含浸紙を化粧単板に熱
圧着する場合、含浸紙のクロス方向を板幅の方向
に一致させて成型する。従つて板幅精度を高める
ためにはこの含浸紙の伸び率についてそのクロス
方向の伸びが影響する。
以上のことから本発明においては含浸紙のクロ
ス方向の伸び率を規制する。次に含浸紙について
その硬化後の伸び率は、含浸紙単体を温度130℃
圧締圧力10Kg／cm2、圧締時間10分の硬化条件にて
硬化させた後、クロス方向を長軸方向として巾15
mm、長さ150mmの試験片を用い毎分10mmの引張速
度で引張り試験を行い、破断時の伸びを測定した
とき、試験前の長さに対する破断時の長さの比率
で与えられる。含浸用基材として使用される薄葉
材、不織布、化繊紙等の坪量としては25〜40ｇ／
m2程度のものを用いる。ここで含浸用基材の坪量
が25ｇ／m2以下の場合は基材に含浸して保持され
るべき樹脂量が不足して所期の性能を付与するこ
とが出来ず、また40ｇ／m2以上の場合は樹脂の含
浸量が過剰となり化粧単板の有する天然物特有の
外観を大幅に損うことになる。一般に表面硬度お
よび耐クラツク性は共に樹脂の含浸量に比例する
が含浸紙コスト、作業性の点からして床材として
の使用目的においては上記含浸基材に対する熱硬
化性樹脂の含浸量は従来一般的に使用されている
合板、化粧単板と同様の範囲、即ち200〜300ｇ／
m2の範囲で充分である。
以上説明した本発明の製造方法においては、硬
化後のクロス方向伸び率が20％以上である熱硬化
性樹脂含浸紙を下層用含浸紙として化粧単板上に
熱圧成型するので比較的大きな収縮膨張の寸法変
化に対しても化粧板表面に保持されてこの寸法変
化を阻止するように作用する一方、外部からの応
力に対しては化粧単板への応力伝達を緩和する。
更に硬化後の伸び率が10％以下である熱硬化性樹
脂含浸紙を上層用含浸紙として下層用含浸紙の上
に積層して熱圧成型することにより大きな表面硬
度が確保され全体として耐クラツク性おび表面硬
度にすぐれる化粧板を製造することができる。ま
た更に本発明の製造方法は、従来の単一含浸紙を
オーバレイする方法に比べて、作業性の点で遜色
がなく、しかも品質性能の点では格段にすぐれた
化粧板を得ることができるので実用上極めて大き
な利点を有する。
次に本発明の実施例を示す。
実施例
(イ) 熱硬化性樹脂含浸紙の製造
坪量24ｇ／m2を有する不織布にジアリルフタレ
ート樹脂を250％含浸し、温度130℃、圧力10Kg／
cm2、時間10分の熱圧硬化条件で硬化させた場合、
それぞれ硬化後のクロス方向伸び率が異なる樹脂
含浸紙を調製した。これらの含浸紙の性質を第１
表に示す。
The present invention relates to a method for manufacturing a surface-hardened decorative board that has a high surface hardness and excellent crack resistance. Conventionally, in order to improve the surface hardness, abrasion resistance, and dimensional stability of decorative laminates, so-called WPC (Wood Plastic
Combination) processing is performed. When using pine or toga wood as a decorative veneer, this WPC treatment can create a more beautiful wood grain. However, in the case of wood with white skin, such as cypress and cedar, used as a decorative turning board, this WPC treatment causes the skin to become more yellowish or take on a yellowish-brown wet color, reducing its commercial value. The disadvantage is that it significantly reduces the On the other hand, there is also a method of overlaying a paper impregnated with a thermosetting resin on the decorative veneer. Although this method provides a satisfactory design, the surface hardness is
It is inferior to that obtained by WPC treatment, and its crack resistance is also insufficient. In general, crack resistance and surface hardness are contradictory properties, so the conventional overlay method, which simply hot-presses a sheet of resin-impregnated paper onto a decorative veneer, satisfies both properties of crack resistance and surface hardness at the same time. It is difficult to manufacture decorative laminates that The present invention uses the method for manufacturing decorative laminates using overlay described above, in which a plurality of impregnated papers with different properties after curing are laminated and pressed onto a decorative veneer, thereby manufacturing a decorative laminate that simultaneously increases crack resistance and surface hardness. Its composition is that a thermosetting resin-impregnated paper with an elongation in the cross direction of 20% or more after the resin cures is layered on a decorative veneer that is adhered to the substrate via an adhesive, and then A thermosetting resin-impregnated paper with a similar elongation of 10% or less is layered on top of the paper, and these are simultaneously hot-press molded. The present invention will be explained in detail below along with examples.
First of all, the decorative veneers used in the present invention include decorative veneers with white wood skin such as cedar and cypress, as well as WPC because resin hardening inhibitors are present in the wood.
A decorative veneer of a tree species that cannot be treated, such as a softwood such as Spanish mackerel or Japanese cedar, or a hardwood such as Japanese zelkova, is used. These decorative veneers are bonded onto the plywood substrate by conventional methods. As the adhesive, a mixed adhesive consisting of a thermosetting resin adhesive and a thermoplastic resin adhesive, such as a mixture of a modified synthetic rubber latex and an amino resin, or a modified rubber latex is suitable. The thermosetting resin-impregnated paper that is bonded by heat and pressure onto the decorative veneer is semi-cured tissue paper, nonwoven fabric, synthetic paper, etc. impregnated with melamine resin, unsaturated polyester resin, acrylic resin, diallyl phthalate resin, etc. . Here, as the impregnated paper for the lower layer, one with an elongation rate in the cross direction after resin curing of 20% or more is used.
The impregnated paper for the upper layer should have an elongation rate of 10% or less in the cross direction after the resin is cured. Here, the elongation in the cross direction refers to the elongation in the direction perpendicular to the longitudinal direction of the fibers in the direction in which the fibers of the impregnated paper are arranged. Generally, when impregnated paper is thermocompression bonded to a decorative veneer, the cross direction of the impregnated paper is aligned with the width direction of the board. Therefore, in order to improve the board width accuracy, the elongation rate of this impregnated paper is influenced by its elongation in the cross direction. From the above, in the present invention, the elongation rate of the impregnated paper in the cross direction is regulated. Next, regarding the impregnated paper, its elongation rate after curing is determined when the impregnated paper itself is heated to 130°C.
After curing under the conditions of a pressing pressure of 10 Kg/cm 2 and a pressing time of 10 minutes, the width is 15 mm with the cross direction as the long axis direction.
When a tensile test is performed using a test piece with a length of 150 mm and a tensile speed of 10 mm per minute, and the elongation at break is measured, it is given as the ratio of the length at break to the length before the test. The basis weight of thin materials, nonwoven fabrics, synthetic paper, etc. used as base materials for impregnation is 25 to 40 g/
Use something about m 2 . If the basis weight of the base material for impregnation is less than 25g/ m2 , the amount of resin to be impregnated and retained in the base material will be insufficient and the desired performance cannot be imparted; If it is 2 or more, the amount of resin impregnated will be excessive and the appearance, which is unique to the natural product of the decorative veneer, will be significantly impaired. In general, both surface hardness and crack resistance are proportional to the amount of resin impregnated, but from the viewpoint of impregnated paper cost and workability, when used as flooring material, the amount of thermosetting resin impregnated into the impregnated base material is conventional. Same range as commonly used plywood and decorative veneer, i.e. 200-300g/
A range of m 2 is sufficient. In the manufacturing method of the present invention described above, thermosetting resin-impregnated paper with a cross-direction elongation rate of 20% or more after curing is used as the lower layer impregnated paper and is hot-press molded on the decorative veneer, so there is relatively large shrinkage. It is held on the surface of the decorative veneer and acts to prevent dimensional changes due to expansion, while also relaxing the transmission of stress to the decorative veneer in response to external stress.
Furthermore, a thermosetting resin-impregnated paper with an elongation rate of 10% or less after curing is used as the upper-layer impregnated paper, and is laminated on top of the lower-layer impregnated paper and hot-press molded to ensure high surface hardness and overall crack resistance. It is possible to produce a decorative board with excellent properties and surface hardness. Furthermore, the manufacturing method of the present invention is comparable in workability to the conventional method of overlaying a single impregnated paper, and it is possible to obtain a decorative board with significantly superior quality performance. It has extremely great practical advantages. Next, examples of the present invention will be shown. Example (a) Production of thermosetting resin-impregnated paper A nonwoven fabric having a basis weight of 24 g/m 2 was impregnated with 250% diallyl phthalate resin, and the temperature was 130°C and the pressure was 10 kg/m2.
cm 2 , when cured under heat-pressure curing conditions for 10 minutes,
Resin-impregnated papers with different cross-direction elongation percentages after curing were prepared. The properties of these impregnated papers are
Shown in the table.
【表】【table】
【表】
(ロ) 化粧板の製造および性能試験
厚さ0.4ｍ／ｍを有する檜スライス単板を酢酸
ビニル系接着剤30％および尿素メラミン系接着剤
70％から成る混合接着剤で基板に貼着後含浸紙Ａ
〜Ｅを温度130℃、圧力10Kg／cm2、時間10分の熱
圧条件で接着し得られた化粧板の表面硬度、耐ク
ラツク性能について試験を行ない次表の結果を得
た。[Table] (B) Manufacture and performance test of decorative board A sliced Japanese cypress veneer with a thickness of 0.4 m/m was coated with a 30% vinyl acetate adhesive and a urea-melamine adhesive.
Impregnated paper A after pasting on the substrate with a mixed adhesive consisting of 70%
- E were bonded together under heat and pressure conditions of 130 DEG C., 10 Kg/cm 2 pressure, and 10 minutes, and tests were conducted on the surface hardness and crack resistance of the decorative laminates, and the results shown in the following table were obtained.
【表】
以上の性能試験から明らかなように、本発明に
係る製造例Ｄ／Ｆは他のものに比べ表面強度およ
び耐クラツク性ともすぐれた性能を有している。
一方、含浸紙が単層のものやＡ／Ｂ，Ａ／Ａ，
Ｄ／Ｂ，Ｂ／Ｆの例は表面硬度または耐クラツク
性のいずれか一方が不充分であり、これに比べ本
発明の製造例に係るものがすぐれていることが判
る。[Table] As is clear from the above performance tests, Production Example D/F according to the present invention has superior performance in surface strength and crack resistance compared to other products.
On the other hand, there are cases where the impregnated paper is a single layer, A/B, A/A,
It can be seen that the examples D/B and B/F were insufficient in either surface hardness or crack resistance, and in comparison, the examples produced according to the present invention were superior.