JP3768300B2

JP3768300B2 - Decorative plate manufacturing method

Info

Publication number: JP3768300B2
Application number: JP21934496A
Authority: JP
Inventors: 寛杉本; 和雅吉田; 純三及川; 泰人寺田
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 1996-07-31
Filing date: 1996-07-31
Publication date: 2006-04-19
Anticipated expiration: 2016-07-31
Also published as: JPH1046796A

Description

【０００１】
【発明の属する技術分野】
本発明は、建築用床材等の建築内装材料や家具用材料として使用するのに好適な化粧板の製造方法に関するものである。
【０００２】
【従来の技術】
従来から、合板などの木質材からなる基板の表面または表裏両面に、突板や合成樹脂製の化粧シート又は印刷紙等の化粧シートを貼着したり、或いは塗装等を行って、表面化粧層を施してなる化粧板が、住宅等の建築物の床材や造作材或いは家具用材料として広く使用されている。しかしながら、例えば合板の表面に突板を貼着したのち、塗装仕上げしてなる一般的な化粧板を床材に使用した場合、湿気の吸収、放散に伴う合板の膨張、収縮によって表面の突板に細かい亀裂（干割れ）が生じたり、表面に重量の大きい家具の脚や落下物などによる局部的な荷重が加わると凹みが生じたりして外観を損なうという問題点がある。
【０００３】
このため、合板等の木質材料からなる基板の表面または表裏両面に中比重木質繊維板（ＭＤＦ）等の木質繊維板を接着して複合板を形成し、この複合板の木質繊維板の表面に突き板や合成樹脂製化粧シート又は印刷紙等の化粧シートを貼着したり、塗装等によって表面化粧層を形成してなる化粧板を床材等の建築材料などに使用する試みがなされている。
【０００４】
このような化粧板の構成部材として使用されている上記木質繊維板は、木質繊維に熱硬化性樹脂接着剤を添加し、加熱下で圧締成形することによって得られたものであるため、加熱面に直接接する表裏層部が高密度に形成され、内部は相対的に低密度に形成されることになる。従って、この木質繊維板を合板などの基板に積層接着して得られた複合板の表面に上記のような表面化粧層を施すと、表面が緻密で硬質且つ平滑であり、収縮の方向性が少ない木質繊維板によって表面化粧層に干割れ等の欠点が生じ難くなるものである。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記木質繊維板として通常用いられる中比重木質繊維板の厚さは2.5mm 以上であり、従ってこのような厚みを有する中比重木質繊維板を合板等の木質基板の片面に接着すると、基板と中比重木質繊維板との収縮率の差や方向性の相違によって化粧板に反りが発生しやすくなる。一方、木質基板の表裏両面に上記中比重木質繊維板を接着させると反りの問題は軽減されるが全体の厚みが厚くなり、製品が高価につくと共に生産効率も悪くなるという問題点が生じる。
【０００６】
さらに、上記のような厚みを有する中比重木質繊維板を使用すると、高密度の表裏層部に比べて内部の低密度層の厚みの割合が大きいために、このような中比重木質繊維板を備えた上記化粧板をダイニングルームの床材に適用した場合、キャスター付ワゴン等による動的荷重や家具の脚等による局部荷重によって中比重木質繊維板の低密度層に層間剥離が生じたり、中比重木質繊維板に凹みが発生して強度が低下すると共に表面の外観を損なうことがある。また、低密度層の厚みが大きいと反りや膨れも発生し易くなる。
【０００７】
このような問題は、中比重木質繊維板の厚みを薄くすれば改善し得るが、厚みが３mm未満の中比重木質繊維板を得るには、現状の製造方法では生産性がきわめて悪く且つ高価につくという問題点がある。本発明はこのような問題点を解消し得る化粧板の製造方法の提供を目的とするものである。
【０００８】
【課題を解決するための手段】
上記目的を達成するために本発明の化粧板は、一方の面側が高密度層で他方の面側が低密度層に形成された中比重木質繊維板の低密度層を研削することによって得られた上記高密度層からなる厚さが２mm以下で密度が0.75〜1.1g/cm³の木質繊維板を木質基板の少なくとも表面に接着してあり、さらに、この木質繊維板上に表面化粧層を設けた構造を有している。
【０００９】
請求項１に係る発明は上記化粧板の製造方法であって、表裏層部が高密度で芯層部が低密度の中比重木質繊維板を、その厚さ方向の中央部から表裏層部に水平な方向に２分割することにより、一方の面側が高密度層で他方の面側が低密度層に形成された傾斜密度を有する中比重木質繊維板を作製し、この中比重木質繊維板の高密度層側の面を木質基材の少なくとも表面に貼着したのち、低密度層を研削除去して厚さが２mm以下で密度が0.75〜1.1g/cm³の木質繊維板に形成し、しかるのち、この木質繊維板上に化粧層を設けることを特徴とするものである。
【００１０】
【作用】
木質基板の表面又は表裏面に貼着した木質繊維板は、表裏層部が高密度で芯層部が低密度の通常の中比重木質繊維板を、その厚さ方向の中央部から２分割することにより、一方の面側が高密度層で他方の面側が低密度層に形成された傾斜密度を有する中比重木質繊維板を作製したのち、低密度層を研削除去することによって得られたものであるから、多量生産が可能となるばかりでなく、その低密度層の研削除去は、高密度層側を木質基材に貼着した状態にして行うものであるから、容易に且つ能率良く行え、厚さが２mm以下で密度が0.75〜1.1g/cm³の精度のよい木質繊維板を簡単に得ることができる。
【００１１】
この薄肉木質繊維板を木質基板に積層接着しているので、木質基板の収縮力や方向性に対して木質繊維板は殆ど影響せず、反りの発生を減少させることができると共に木質繊維板は密度が0.75〜1.1g/cm³の比較的高密度に形成されているので、ワゴンのキャスター等による動的荷重や家具の脚等からの局部荷重を受けても凹みや層間剥離現象が生じ難く、且つ反りや膨れも発生し難い耐久性に優れた化粧板を提供し得るものである。
【００１２】
【発明の実施の形態】
次に、本発明の実施例を図面に基づいて詳述すると、図１において、化粧板Ａは所望厚みを有する木質基板１と、この木質基板１の表面に積層接着することにより一体に貼着された厚さが２mm以下で密度が0.75〜1.1g/cm³の木質繊維板２と、この木質繊維板２の表面に層着された表面化粧層３とから構成されている。なお、木質繊維板２にはその表面又は裏面から他面に向かって貫通する又は半貫通の多数の微小孔（図示せず）を全面に亘って均一に設けておくことが望ましい。
【００１３】
上記木質基板１としてはパーティクルボード、ウエハーボード、ストランドボード等の木削片板や、合板、集成材、ＬＶＬ、木質繊維板等の木質板が使用される。一方、木質基板１に積層接着した木質繊維板２としては、通常の中比重木質繊維板の緻密な表裏層部を主に含む繊維板を使用している。この木質繊維板２の表面に層着する化粧層としては、突板やＷＰＣ単板、印刷紙、塩化ビニールシートであってもよく、塗料の塗布層であってもよい。
【００１４】
このような化粧板の製造方法の一例を述べると、まず、厚みが3.5mm 以下の中比重木質繊維板から上記木質繊維板２を作製する。一般に、中比重木質繊維板を製造するには熱硬化性樹脂等の接着剤を添加した木質繊維をマット状に成形したのち、このマット状物を上下に熱圧プレートを備えたバッチ式ホットプレスや無端状に巡回するベルト状の上下熱圧プレートを備えた連続プレス装置で板状に熱圧成形することによって製造されるものであるが、得られた中比重木質繊維板2Aは、図２に示すように、上下熱圧プレートに接する表裏面が平滑面で且つ緻密な高密度層2aに形成され、内部は低密度層2bとなっている。
【００１５】
この中比重木質繊維板2Aを、中間層である低密度層2bをその厚さ方向の中央部から上下に２分割して図３に示すように、一方の面が高密度層2aで他方の面が低密度層2bに形成された傾斜密度を有している厚みの薄い中比重木質繊維板2Bとする。なお、このような中比重木質繊維板2Bは次に列記するような方法によって得ることができる。すなわち、
▲１▼．上記常法によって中比重木質繊維板2Aを製造する際に、マット状物の中間層に網状物などの微小凹凸面を有するシート状物を介在させておき、成形後にこのシート状物を介して中間層から２分することにより、表裏にそれぞれ高密度層と低密度層を有する２枚の薄い中比重木質繊維板2B、2Bを得る。
▲２▼．上記常法によって中比重木質繊維板2Aを製造する際に、マット状物の中間層に接着剤を塗布しない層を設けておき、このマット状物を加熱、加圧した後、該い中間層で剥離を生じさせて２分することにより、表裏にそれぞれ高密度層と低密度層を有する２枚の薄い中比重木質繊維板2B、2Bを得る。
▲３▼．上記常法によって得られた厚みのある中比重木質繊維板2Aを、その厚み方向の中央部から割裂させて２分することにより、表裏にそれぞれ高密度層と低密度層を有する２枚の薄い中比重木質繊維板2B、2Bを得る。
【００１６】
このようにして得られた中比重木質繊維板2Bは、一方の面側は密度が0.8 〜1.1g/cm³程度の高密度層2aで他方の面側は密度が0.4 〜0.7g/cm³程度の低密度層2bであり、且つ一方の面から他方の面に向かって徐々に密度が小さくなった密度傾斜を有したものとなっている。なお、この中比重木質繊維板2Bに高密度層2aの表面側から低密度層2bに向かって貫通する又は半貫通の多数の微小孔を全面に亘って均一に穿設しておいてもよい。この微小孔の形状、大きさは後述する接着剤や塗料が浸透できる形状、大きさの細孔であればよい。
【００１７】
このような微小孔を設けた中比重木質繊維板2Bは、次に列記するような手段によって得ることができる。即ち、
▲１▼．周面に多数の微小突起を設けた回転ロールやプレートを中比重木質繊維板2Bの高密度層2aの表面に押圧することによって形成する。
▲２▼．中比重木質繊維板2Aを製造する際の熱圧成形時に、対向する熱圧プレート面に多数の微小突起を突設した型材を装着しておき、熱圧成形と同時に形成する。
▲３▼．中比重木質繊維板2Aを製造する際に、その中間層に剥離層や割裂層を設けておき、この中比重木質繊維板2Aの高密度層である表裏面を周面に多数の微小突起を突設してなる上下一対の回転ロールによって挟圧したのち剥離層や割裂層を介して２分させる。
【００１８】
次いで、中比重木質繊維板2Bの高密度層2a側を図４に示すように、上記木質基板１の表面又は表裏両面に接して接着剤４を介して重ね合わせ、一体に接着する（図４は表面に重ね合わせた場合だけを例示する）。接着手段としてはコールドプレス、或いはホットプレスのいずれであってもよい。
【００１９】
木質基板１と中比重木質繊維板2Bの高密度層2aとを接着する接着剤４としては通常は、尿素−ホルマリン樹脂、尿素−メラミン−ホルマリン樹脂、メラミン−フェノール−ホルマリン樹脂、アルキルフェノールホルマリン樹脂、ウレタン樹脂、エポキシ樹脂、水性ビニルウレタン樹脂エマルジョン、酢ビ−尿素系水性樹脂、アクリル−メラミン系水性エマルジョン、ポバール−イソシアネート水性エマルジョンなど、酢酸ビニル系、尿素樹脂系、メラミン樹脂系、フェノール系、ウレタン系、エポキシ系の接着剤を使用する。
【００２０】
上記接着剤４を木質基板１と中比重木質繊維板2Bの高密度層2aとの対向面のいずれか一方に塗布したのち加圧すると、接着剤４が木質基板１と高密度層2aとの接合面全面の繊維層内に浸透して木質基板１と中比重木質繊維板2Bとが接着一体化する。この際、上記のように中比重木質繊維板2Bの高密度層2aに微小孔を設けておくことによって一部の接着剤４がこの微小孔内に浸入して固化し、さらに、該微小孔内から高密度層2aの繊維層内に浸透して該高密度層2aを強化し、木質基板１と中比重木質繊維板2Bの高密度層2aが強固に接着一体化する。
【００２１】
このように木質基板１の表面に接着剤４によって中比重木質繊維板2Bの高密度層2aを貼着したのち、表面に露呈している該中比重木質繊維板2Bの低密度層2bをサンディングやブラッシング等の研削手段によって研削除去することにより図５に示すように、厚さが２mm以下で密度が0.75〜1.1g/cm³の木質繊維板２に形成するものである。なお、中比重木質繊維板2Bは高密度層2aの露出面から低密度層2bの露出面に向かって上述したように密度傾斜を有しているので、低密度層2bを全て研削除去することなく多少残存させておいてもよい。
【００２２】
次いで、中比重木質繊維板2Aの低密度層2bの研削除去によって露出した木質繊維板２の高密度層2aの露出面に図６に示すように、表面化粧層３を層着することによって化粧板Ａを作製する。このような化粧層３を施すには▲１▼．木質繊維板２に突板やＷＰＣ単板、或いは印刷紙、塩化ビニル樹脂シート等の化粧シートを接着剤５により貼着する、▲２▼．木質繊維板２に塗装したり直接印刷する、▲３▼．下地塗りを行ったのち塗装仕上げを行う、などの方法があり、さらに、これらの方法を組み合わせてもよい。木質繊維板２に化粧単板又は化粧シートを接着して化粧層３を形成するには、木質繊維板２と化粧単板又は化粧シートとの対向面に接着剤５を塗布したのちコールドプレス或いはホットプレスによって一体化させる。
【００２３】
この際、上記のように木質繊維板２に表裏面間に亘って貫通する多数の微小孔を設けておくと、加圧時に接着剤５の一部が木質繊維板２の表面に開口している上記多数の微小孔に浸入して固化することによりアンカー作用を奏すると共に微小孔から木質繊維板２の高密度層2a内に浸透して木質繊維板２に化粧層３を強固に層着一体化させることができ、使用条件が厳しい環境下においても剥離現象が生じ難くなると共に局部荷重に対しても充分に耐えることができる化粧板Ａが得られる。木質繊維板２の表面に塗料を塗布する場合も同様であり、塗料の一部が微小孔内に浸入して塗料の層着が強固に行われて密着性が良好となる。
【００２４】
また、木質繊維板２にダイレクト印刷や極薄の化粧材を層着して化粧層３を形成した場合、木質繊維板２側の欠点が表面に現出する等の好ましくない現象が生じる虞れがあるので、この場合には、下地塗装等を施したのち化粧仕上げを行うものである。次に、本発明の具体的な実施例を示す。
【００２５】
〔実施例１〕
表裏面から内部に向かって0.1 〜0.6mm の厚み部分の平均密度が0.87g/cm³ で且つ厚さ方向の中央から表裏面に向かってそれぞれ0.5mm の厚み部分、即ち、中央の厚さ1.0mm 部分の平均密度が0.65g/cm³ に形成されている平均比重0.74、厚さ３mmの中比重木質繊維板を、その厚さ方向の略中央から２分割して厚さが約1.5mm の表層側が高密度層で裏層側が低密度層の２枚の中比重木質繊維板を得た。この分割した中比重木質繊維板の１枚を、厚さ９mmの合板からなる木質基板の表面に中比重木質繊維板の高密度層側を水性ビニルウレタン接着剤にて接着して複合板に形成した。次いで、この複合板の表面の中比重木質繊維板の低密度層をサンディングして約0.5mm を除去し、木質基板の表面に厚さが1.0mm 、密度が約0.8g/cm³の高密度層を主に含む木質繊維板層を形成した。次いでこの木質繊維板層の表面に厚さ0.4mm の合成樹脂含浸化粧突板をビニルウレタン樹脂接着剤にて接着して化粧板を得た。このようにして得られた化粧板は、木質繊維板層が1.0mm と薄く且つ密度の高い層から形成されているので、反り等の発生や木質繊維板層の層間剥離の発生が殆ど生じないものであった。
【００２６】
〔実施例２〕
実施例１で得た厚さが約1.5mm の表層側が高密度層で裏層側が低密度層の中比重木質繊維板の高密度層側の表面に、周囲に多数の微小突起を設けた回転ロールを押し付けることにより深さが約0.9mm 、長さ３mm、幅0.15mmの多数の微小孔を形成した。この中比重木質繊維板を実施例１と同様にして木質基板の表面に接着して複合板に形成した。次いで、この複合板の表面の中比重木質繊維板の低密度層をサンディングして約0.5mm を除去し、木質基板の表面に厚さが1.0mm 、密度が約0.8g/cm³の高密度層を主に含む木質繊維板層を形成した。次いでこの木質繊維板層の表面に厚さ0.4mm の突板をビニルウレタン樹脂接着剤にて接着して化粧板を得た。この化粧板は、上記実施例１の効果に加えて、中比重木質繊維板と木質基板との接着が、中比重木質繊維板の微小孔内に接着剤が浸透するために、木質繊維板層が浸透した接着剤により強化されて耐層間剥離性がさらに向上していた。また、中比重木質繊維板の低密度層をサンディングすることにより、微小孔が複合板の表面に露出するので、突板との接着も同様に強固になっていた。
【００２７】
【発明の効果】
以上のように本発明によれば、木質基板の表面又は表裏面に貼着した木質繊維板は、厚さが２mm以下の薄肉であって密度が0.75〜1.1g/cm³に形成されているので、木質基板の収縮力や方向性に対して木質繊維板は殆ど影響せず、反りの発生を減少させることができると共に木質繊維板は密度が0.75〜1.1g/cm³の比較的高密度に形成されているので、ワゴンのキャスターによる動的荷重や家具の脚等からの局部荷重を受けても層間剥離や凹み現象が生じ難い耐久性に優れた化粧板を提供し得るものである。
【００２８】
さらに、この化粧板の製造方法によれば、まず、表裏層部が高密度で芯層部が低密度の中比重木質繊維板を、その厚さ方向の中央部から表裏層部に水平な方向に２分割することにより、一方の面側が高密度層で他方の面側が低密度層に形成された傾斜密度を有する中比重木質繊維板を作製したのち、低密度層を研削除去するものであるから、表裏層がそれぞれ高密度層と低密度層である薄肉の中比重木質繊維板を生産性よく且つ安価に得ることができると共にその低密度層の研削除去は、高密度層側を木質基材に貼着した状態にして行うものであるから、容易に且つ能率良く行え、厚さが２mm以下で密度が0.75〜1.1g/cm³の精度のよい木質繊維板を簡単に得ることができる。
【００２９】
また、木質基板に積層接着した上記中比重木質繊維板の高密度層からなる木質繊維板に、表裏面間に亘って貫通した多数の微小孔を全面に亘って穿設しておくことによって、この木質繊維板を木質基板に接着剤を介して接着した時や該木質繊維板の表面に接着剤によって突板や化粧シート等の化粧板を貼着する場合に、接着剤の一部が上記微小孔に食い込んでアンカー作用を発揮し、表面が緻密な該木質繊維板表面に対する密着性や接着性が強固となると共に微小孔に通じて木質繊維板の高密度層内に接着剤を浸透させて硬化層を形成することができ、従って、耐水、耐膨張性及び耐圧強度が向上し、且つ表面硬度も大きくて局部荷重や繰り返し荷重に対する充分な抵抗力を有する化粧板が得られる。
【図面の簡単な説明】
【図１】化粧板の簡略斜視図、
【図２】木質繊維板の得るための中比重木質繊維板の簡略断面図、
【図３】高密度層と低密度層との２層から中比重木質繊維板の簡略断面図、
【図４】木質基板の表裏面に上記２層を有する中比重木質繊維板を貼着した状態の簡略断面図、
【図５】低密度層を研削除去して高密度層からなる木質繊維板に形成した状態の簡略断面図、
【図６】木質繊維板表面に化粧層を設けた状態の簡略断面図。
【符号の説明】
１木質基板
２木質繊維板
2a 高密度層
2b 低密度層
３表面化粧層
４、５接着剤
Ａ化粧板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method of the preferred veneer for use as building interior materials and furniture materials, such as building flooring.
[0002]
[Prior art]
Conventionally, a decorative sheet such as a veneer or a synthetic resin decorative sheet or printing paper is applied to the surface or both front and back surfaces of a substrate made of a wood material such as plywood, or the surface decorative layer is formed by painting or the like. An applied decorative board is widely used as a flooring material, a building material or a furniture material of a building such as a house. However, for example, when a veneer is applied to the surface of a plywood and then used as a flooring material, the surface veneer is fine due to the absorption and absorption of moisture, and the expansion and contraction of the plywood. There is a problem that cracks (dry cracks) occur, and when a local load such as heavy furniture legs or falling objects is applied to the surface, dents are formed and the appearance is impaired.
[0003]
For this reason, a wood fiber board such as medium specific gravity wood fiber board (MDF) is bonded to the surface or both sides of the board made of wood material such as plywood to form a composite board, and the surface of the wood fiber board of this composite board Attempts have been made to use veneers, synthetic resin decorative sheets or decorative sheets such as printing paper, or decorative sheets formed with a surface decorative layer by painting or the like for building materials such as flooring. .
[0004]
The wood fiber board used as a component of such a decorative board is obtained by adding a thermosetting resin adhesive to the wood fiber and press-molding under heating. The front and back layer portions that are in direct contact with the surface are formed with a high density, and the inside is formed with a relatively low density. Therefore, when the above-mentioned surface decorative layer is applied to the surface of the composite board obtained by laminating and bonding this wood fiber board to a substrate such as plywood, the surface is dense, hard and smooth, and the direction of shrinkage is A small amount of wood fiber board makes it difficult for defects such as dry cracks to occur in the surface decorative layer.
[0005]
[Problems to be solved by the invention]
However, the thickness of the medium specific gravity wood fiber board normally used as the above wood fiber board is 2.5 mm or more. Therefore, when the medium specific gravity wood fiber board having such a thickness is bonded to one surface of a wooden board such as plywood, And the decorative board are likely to warp due to the difference in shrinkage and the directionality between the medium specific gravity wood fiber board. On the other hand, when the medium specific gravity wood fiber board is bonded to both the front and back surfaces of the wood substrate, the problem of warpage is reduced, but the overall thickness increases, resulting in a problem that the product is expensive and the production efficiency is deteriorated.
[0006]
Furthermore, when the medium specific gravity wood fiber board having the above thickness is used, the ratio of the thickness of the internal low density layer is larger than that of the high density front and back layer parts. When the above decorative board is applied to the flooring of a dining room, delamination may occur in the low density layer of the medium specific gravity wood fiber board due to dynamic loads such as wagons on casters and local loads such as furniture legs. A dent may be generated in the specific gravity wood fiber board to reduce the strength and damage the appearance of the surface. Further, when the thickness of the low density layer is large, warping and swelling are likely to occur.
[0007]
Such a problem can be improved by reducing the thickness of the medium specific gravity wood fiber board. However, in order to obtain a medium specific gravity wood fiber board having a thickness of less than 3 mm, the current manufacturing method is extremely inefficient and expensive. There is a problem of sticking. The present invention is intended to provide a method for manufacturing a decorative plate that can overcome the above problems.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the decorative board of the present invention was obtained by grinding a low density layer of a medium specific gravity wood fiber board in which one surface side was formed as a high density layer and the other surface side was formed as a low density layer. A wood fiber board having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ composed of the above high-density layer is adhered to at least the surface of the wood board, and a surface decorative layer is provided on the wood fiber board. Have a structure.
[0009]
The invention according to claim 1 is a method of manufacturing the decorative board, wherein the medium specific gravity wood fiber board having a high density in the front and back layers and a low density in the core layer is formed from the center in the thickness direction to the front and back layers. By dividing into two in the horizontal direction, a medium specific gravity wood fiber board having a gradient density in which one surface side is formed in a high density layer and the other surface side is formed in a low density layer is produced. After the surface of the density layer is attached to at least the surface of the wood substrate, the low density layer is ground and removed to form a wood fiber board having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ^3. Thereafter, a decorative layer is provided on the wood fiber board.
[0010]
[Action]
The wood fiber board adhered to the front or back surface of the wood substrate is divided into two from the center in the thickness direction of a normal medium specific gravity wood fiber board having a high density in the front and back layers and a low density in the core layer. This was obtained by grinding and removing the low density layer after producing a medium specific gravity wood fiber board having a gradient density in which one surface side was formed into a high density layer and the other surface side was formed into a low density layer. Therefore, not only mass production is possible, but the grinding and removal of the low-density layer is performed with the high-density layer side stuck to the wooden substrate, so it can be easily and efficiently performed, An accurate wood fiber board having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ can be easily obtained.
[0011]
Since this thin wooden fiberboard is laminated and bonded to the wooden substrate, the wooden fiberboard has little effect on the shrinkage force and directionality of the wooden substrate, it can reduce the occurrence of warping and the wooden fiberboard Since it is formed at a relatively high density of 0.75 to 1.1 g / cm ³ , dents and delamination phenomena are unlikely to occur even when receiving dynamic loads from wagon casters or local loads from furniture legs. In addition, it is possible to provide a decorative plate excellent in durability that hardly warps or bulges.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, a decorative board A is adhered to a wooden substrate 1 having a desired thickness by laminating and adhering to the surface of the wooden substrate 1. The wood fiber board 2 has a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ , and a surface decorative layer 3 layered on the surface of the wood fiber board 2. The wood fiber board 2 is desirably provided with a large number of fine holes (not shown) penetrating from the front surface or the back surface toward the other surface or semi-penetrating over the entire surface.
[0013]
As the wood substrate 1, a wood board such as a particle board, a wafer board or a strand board, or a wood board such as a plywood, a laminated wood, an LVL or a wood fiber board is used. On the other hand, as the wood fiber board 2 laminated and bonded to the wood substrate 1, a fiber board mainly including dense front and back layer portions of a normal medium specific gravity wood fiber board is used. The decorative layer to be layered on the surface of the wood fiber board 2 may be a veneer, a WPC single board, printing paper, a vinyl chloride sheet, or a coating layer of paint.
[0014]
An example of a method for producing such a decorative board will be described. First, the wood fiber board 2 is produced from a medium specific gravity wood fiber board having a thickness of 3.5 mm or less. In general, in order to produce a medium specific gravity wood fiberboard, a wood fiber fiber to which an adhesive such as a thermosetting resin is added is formed into a mat shape, and then the mat-like material is batch-type hot press equipped with a hot press plate up and down. 2A, the medium specific gravity wood fiber board 2A obtained is produced by hot-pressing into a plate shape with a continuous press device having belt-like upper and lower hot-pressing plates that circulate endlessly. As shown in the figure, the front and back surfaces in contact with the upper and lower hot-pressing plates are formed into a smooth and dense high-density layer 2a, and the inside is a low-density layer 2b.
[0015]
The medium specific gravity wood fiber board 2A is divided into a low-density layer 2b, which is an intermediate layer, vertically divided from the center in the thickness direction, and as shown in FIG. 3, one surface is a high-density layer 2a and the other is A thin medium specific gravity wood fiber board 2B having a gradient density formed on the low density layer 2b is used. Such a medium specific gravity wood fiber board 2B can be obtained by the following method. That is,
(1). When the medium specific gravity wood fiber board 2A is manufactured by the above-described conventional method, a sheet-like material having a fine uneven surface such as a net-like material is interposed in the intermediate layer of the mat-like material, and after the molding, Two thin medium specific gravity wood fiber boards 2B and 2B each having a high density layer and a low density layer on the front and back are obtained by dividing into two from the intermediate layer.
(2). When the medium specific gravity wood fiber board 2A is manufactured by the above-mentioned conventional method, a layer not coated with an adhesive is provided on the intermediate layer of the mat-like material, and after heating and pressurizing the mat-like material, the intermediate layer The two thin medium-density wood fiber boards 2B and 2B each having a high-density layer and a low-density layer on the front and back are obtained by causing separation at 2 for 2 minutes.
(3). By splitting the thick medium specific gravity wood fiber board 2A obtained by the above-mentioned conventional method from the center in the thickness direction and dividing it into two, two thin sheets having a high density layer and a low density layer on the front and back sides respectively. Medium specific gravity wood fiber boards 2B and 2B are obtained.
[0016]
The medium specific gravity wood fiber board 2B thus obtained has a high density layer 2a having a density of about 0.8 to 1.1 g / cm ³ on one side and a density of 0.4 to 0.7 g / cm ³ on the other side. The low-density layer 2b has a density gradient in which the density gradually decreases from one surface to the other surface. In addition, a large number of micro-holes penetrating from the surface side of the high-density layer 2a toward the low-density layer 2b or semi-penetrating may be uniformly formed in the medium specific gravity wood fiber board 2B over the entire surface. . The shape and size of the micropores may be any shape and size that can be penetrated by an adhesive or paint described later.
[0017]
The medium specific gravity wood fiber board 2B provided with such fine holes can be obtained by the means listed below. That is,
(1). It is formed by pressing a rotating roll or plate having a large number of minute protrusions on the peripheral surface against the surface of the high density layer 2a of the medium specific gravity wood fiber board 2B.
(2). At the time of hot-pressure forming when manufacturing the medium specific gravity wood fiber board 2A, a mold member having a large number of minute protrusions is mounted on the opposing hot-pressure plate surface, and is formed simultaneously with the hot-pressure forming.
(3). When manufacturing the medium specific gravity wood fiber board 2A, an intermediate layer is provided with a release layer and a splitting layer, and a large number of microprojections are formed on the front and back surfaces, which are the high density layers of the medium specific gravity wood fiber board 2A. After being pinched by a pair of upper and lower rotating rolls formed in a projecting manner, it is divided into two minutes via a release layer or a split layer.
[0018]
Next, as shown in FIG. 4, the high density layer 2a side of the medium specific gravity wood fiber board 2B is in contact with the front surface or both front and back surfaces of the wood substrate 1, and is overlapped with the adhesive 4 and bonded together (FIG. 4). Shows only the case where it is superimposed on the surface ). The bonding means may be either a cold press or a hot press.
[0019]
As the adhesive 4 for bonding the wood substrate 1 and the high density layer 2a of the medium specific gravity wood fiber board 2B, usually, urea-formalin resin, urea-melamine-formalin resin, melamine-phenol-formalin resin, alkylphenol formalin resin, Urethane resin, epoxy resin, aqueous vinyl urethane resin emulsion, vinyl acetate-urea aqueous resin, acrylic-melamine aqueous emulsion, poval-isocyanate aqueous emulsion, vinyl acetate, urea resin, melamine resin, phenol, urethane Use epoxy or epoxy adhesives.
[0020]
When the adhesive 4 is applied to one of the opposing surfaces of the wood substrate 1 and the high density layer 2a of the medium specific gravity wood fiber board 2B and then pressed, the adhesive 4 is applied between the wood substrate 1 and the high density layer 2a. The wood substrate 1 and the medium specific gravity wood fiber board 2B are bonded and integrated by penetrating into the fiber layer on the entire joint surface. At this time, by providing micropores in the high-density layer 2a of the medium specific gravity wood fiber board 2B as described above, a part of the adhesive 4 enters and solidifies into the micropores. The high density layer 2a penetrates into the fiber layer of the high density layer 2a from the inside to reinforce the high density layer 2a, and the high density layer 2a of the wood substrate 1 and the medium specific gravity wood fiber board 2B is firmly bonded and integrated.
[0021]
After the high density layer 2a of the medium specific gravity wood fiber board 2B is adhered to the surface of the wood substrate 1 with the adhesive 4, the low density layer 2b of the medium specific gravity wood fiber board 2B exposed on the surface is sanded. As shown in FIG. 5, it is formed on a wood fiber board 2 having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ by grinding and removing by grinding means such as brushing or the like. The medium specific gravity wood fiber board 2B has a density gradient as described above from the exposed surface of the high-density layer 2a to the exposed surface of the low-density layer 2b, so that all the low-density layer 2b is ground and removed. It may be left to some extent.
[0022]
Next, as shown in FIG. 6, makeup is applied by applying a surface decorative layer 3 on the exposed surface of the high density layer 2a of the wood fiber board 2 exposed by grinding and removing the low density layer 2b of the medium specific gravity wood fiber board 2A. Plate A is prepared. To apply such a decorative layer 3, (1). A decorative sheet such as a veneer, a WPC veneer, printing paper, or a vinyl chloride resin sheet is adhered to the wood fiber board 2 with an adhesive 5. (2). Paint or print directly on the wood fiberboard (3). There is a method of performing a paint finish after applying a base coat, and these methods may be combined. In order to bond the decorative veneer or the decorative sheet to the wooden fiber board 2 to form the decorative layer 3, the adhesive 5 is applied to the opposing surface of the wooden fiber board 2 and the decorative veneer or decorative sheet, and then cold press or Integrate by hot pressing.
[0023]
At this time, if the wood fiber board 2 is provided with a large number of minute holes penetrating between the front and back surfaces as described above, a part of the adhesive 5 opens on the surface of the wood fiber board 2 during pressurization. It penetrates into the above-mentioned many micropores and solidifies to exert an anchoring action and penetrates from the micropores into the high density layer 2a of the wood fiber board 2 to firmly attach the decorative layer 3 to the wood fiber board 2 The decorative board A can be obtained, which is less likely to cause a peeling phenomenon even under severe conditions of use and can sufficiently withstand a local load. The same applies to the case where the paint is applied to the surface of the wood fiber board 2, and a part of the paint enters into the micropores so that the coating is firmly applied and the adhesion is improved.
[0024]
Further, when the decorative layer 3 is formed by layering a direct printing or ultra-thin cosmetic material on the wood fiber board 2, an undesirable phenomenon such as a defect on the wood fiber board 2 appearing on the surface may occur. Therefore, in this case, a makeup finish is performed after applying a base coating or the like. Next, specific examples of the present invention will be described.
[0025]
[Example 1]
The average density of the thickness portion of 0.1 to 0.6 mm from the front and back surfaces to the inside is 0.87 g / cm ³ and the thickness portion is 0.5 mm from the center in the thickness direction to the front and back surfaces, that is, the thickness of the center is 1.0. An average specific gravity of 0.74 and an average specific gravity of 0.74, with a thickness of 3 mm, formed into an average density of 0.65 g / cm ³ are divided into two from the approximate center in the thickness direction, and the thickness is about 1.5 mm. Two medium specific gravity wood fiber boards having a high density layer on the surface side and a low density layer on the back layer side were obtained. One of these divided medium specific gravity wood fiberboards is bonded to the surface of a wood substrate made of 9mm thick plywood, and the high density layer side of the medium specific gravity wood fiberboard is bonded with an aqueous vinyl urethane adhesive to form a composite board. did. Next, sanding the low density layer of the medium specific gravity wood fiber board on the surface of this composite board removes about 0.5 mm, and the thickness of the wood board surface is 1.0 mm and the density is about 0.8 g / cm ³ A wood fiberboard layer mainly containing the layer was formed. Next, a synthetic resin-impregnated decorative veneer having a thickness of 0.4 mm was adhered to the surface of the wood fiber board layer with a vinyl urethane resin adhesive to obtain a decorative board. The decorative board obtained in this way has a thin wood fiber board layer as thin as 1.0 mm and is formed from a high density layer, so there is almost no occurrence of warpage or delamination of the wood fiber board layer. It was a thing.
[0026]
[Example 2]
The rotation obtained by providing a large number of microprojections around the surface of the high-density layer side of the medium specific gravity wood fiberboard having a thickness of about 1.5 mm obtained in Example 1 and having a high-density layer on the surface side and a low-density layer on the back layer side By pressing the roll, a large number of micropores having a depth of about 0.9 mm, a length of 3 mm, and a width of 0.15 mm were formed. This medium specific gravity wood fiber board was bonded to the surface of the wood substrate in the same manner as in Example 1 to form a composite board. Next, sanding the low density layer of the medium specific gravity wood fiber board on the surface of this composite board removes about 0.5 mm, and the thickness of the wood board surface is 1.0 mm and the density is about 0.8 g / cm ³ A wood fiberboard layer mainly containing the layer was formed. Next, a veneer having a thickness of 0.4 mm was adhered to the surface of the wood fiber board layer with a vinyl urethane resin adhesive to obtain a decorative board. In addition to the effects of the first embodiment, this decorative board has a wood fiber board layer because the adhesive between the medium specific gravity wood fiber board and the wood substrate penetrates into the micropores of the medium specific gravity wood fiber board. The delamination resistance was further improved by being reinforced by the adhesive penetrated by. Moreover, since the micropores are exposed on the surface of the composite board by sanding the low density layer of the medium specific gravity wood fiber board, the adhesion to the projecting board is similarly strong.
[0027]
【The invention's effect】
As described above, according to the present invention, the wood fiber board adhered to the front surface or the front and back surfaces of the wood substrate has a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ . Therefore, the wood fiber board has little influence on the shrinkage force and directionality of the wood substrate, can reduce the occurrence of warping, and the wood fiber board has a relatively high density of 0.75 to 1.1 g / cm ³ . Therefore, it is possible to provide a decorative plate excellent in durability, which does not easily cause delamination or dent even when subjected to a dynamic load by a wagon caster or a local load from a furniture leg or the like.
[0028]
Furthermore, according to this method for producing a decorative board, first, a medium specific gravity wood fiber board having a high density in the front and back layers and a low density in the core layer is arranged in a horizontal direction from the center in the thickness direction to the front and back layers. By dividing into two, a medium specific gravity wood fiberboard having a gradient density in which one surface side is formed into a high density layer and the other surface side is formed into a low density layer is manufactured, and then the low density layer is ground and removed. Therefore, a thin-walled medium specific gravity wood fiberboard whose front and back layers are a high-density layer and a low-density layer, respectively, can be obtained with good productivity and at a low cost, and the low-density layer is ground and removed. Since it is performed in a state where it is adhered to the material, it can be easily and efficiently performed, and it is possible to easily obtain an accurate wood fiber board having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ^3. .
[0029]
In addition, by boring a large number of fine holes penetrating between the front and back surfaces over the entire surface of the wood fiber board consisting of the high density layer of the medium specific gravity wood fiber board laminated and adhered to the wood substrate, When this wood fiber board is bonded to a wood substrate with an adhesive or when a decorative board such as a veneer or a decorative sheet is attached to the surface of the wood fiber board with an adhesive, a part of the adhesive is the above-mentioned minute It penetrates into the hole and exerts an anchoring action, and the adhesion and adhesion to the surface of the wood fiber board having a dense surface are strengthened, and the adhesive penetrates into the high density layer of the wood fiber board through the micro holes. A hardened layer can be formed, and thus a decorative board having improved water resistance, expansion resistance and pressure strength, and having a large surface hardness and sufficient resistance to local loads and repeated loads can be obtained.
[Brief description of the drawings]
FIG. 1 is a simplified perspective view of a decorative board,
FIG. 2 is a simplified cross-sectional view of a medium specific gravity wood fiber board for obtaining a wood fiber board,
FIG. 3 is a simplified cross-sectional view of a medium specific gravity wood fiber board from two layers of a high density layer and a low density layer,
FIG. 4 is a simplified cross-sectional view of a state in which a medium specific gravity wood fiber board having the above two layers is attached to the front and back surfaces of a wood substrate;
FIG. 5 is a simplified cross-sectional view showing a state in which a low-density layer is ground and removed to form a wood fiber board composed of a high-density layer;
FIG. 6 is a simplified cross-sectional view showing a state in which a decorative layer is provided on the surface of a wood fiber board.
[Explanation of symbols]
1 Wood substrate 2 Wood fiber board
2a High density layer
2b Low density layer 3 Surface decorative layer 4, 5 Adhesive A Decorative plate

Claims

By dividing the medium specific gravity wood fiberboard with a high density in the front and back layers and a low density in the core layer into two in the horizontal direction from the center in the thickness direction to the front and back layers, one side is the high density layer Then, the medium specific gravity wood fiberboard having the gradient density formed on the other surface side in the low density layer is prepared, and the surface on the high density layer side of this medium specific gravity wood fiberboard is adhered to at least the surface of the wood substrate. The low density layer is ground and removed to form a wood fiber board having a thickness of 2 mm or less and a density of 0.75 to 1.1 g / cm ³ , and then a decorative layer is provided on the wood fiber board. A method for producing a decorative board.