JP2004315548A - Biomass derived hard polyurethane foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomass substance derived polyurethane foam which has strength properties of a foam by no means inferior to those of the conventional synthetic polyol derived foam, and makes the most of the characteristics of a biomass substance. <P>SOLUTION: The biomass substance derived polyurethane foam is obtained by reacting a polyol composition comprising ≥30 wt.% biomass-derived polyol with a polyisocyanate, and the polyurethane foam has a cell communicating ratio of ≥65% and an S<SB>I</SB>represented by formula (I): S<SB>I</SB>=y/x<SP>2</SP>[wherein y is a compression strength (Pa), and x is a density (kg/m<SP>3</SP>)] of ≥80. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２９】
なお、バイオマス物質反応率は、変性反応生成物中の未反応固形バイオマス物質を濾別、定量して、求められる。
【００３０】
バイオマス物質の脱水量は、好ましくは４〜１８％である。脱水量が３％以下であると、バイオマス物質の変性反応が不充分であると共に、バイオマス物質が本来含有する多量の水酸基がそのまま残るので、バイオマス由来ポリオールの極性が高く、他のポリオール系組成物および／またはポリイソシアネートと混合する際にバイオマス物質由来の成分が分離したり沈殿することがある。また、バイオマス由来ポリオールが分離するとともに、水酸基価が高すぎるために、脆い発泡体となる。一方、脱水量が２０％を超えると、バイオマス由来ポリオールの水酸基価が極端に低下し、硬質ポリウレタン発泡体の架橋密度が低く、所望の強度が得られない。
【００３１】
得られたバイオマス由来ポリオールの水酸基価は、たとえばフタル酸エステル化法により測定する。好適な水酸基価範囲は２５０〜５００ｍｇＫＯＨ／ｇ、さらに好ましくは３００〜４５０ｍｇＫＯＨ／ｇである。水酸基価が、２５０ｍｇＫＯＨ／ｇ未満の場合、得られた発泡体の架橋密度が低く、所望の強度が得られない傾向があり、５００ｍｇＫＯＨ／ｇを超えると、バイオマス由来ポリオールとポリイソシアネートとの反応における発熱量が大きく、発泡体に焦げ跡（スコーチ）などの欠陥が発生しやすくなる傾向がある。
【００３２】
本発明のポリオール系組成物は、液化工程で得られたバイオマス由来ポリオールのほかに、相溶化ポリオールなどを含み、発泡剤、整泡剤などの存在下でポリイソシアネートとの反応を経て、発泡体に調製される。
【００３３】
一般にバイオマス由来ポリオールは、発泡剤、整泡剤などの通常の硬質ポリウレタン発泡体の配合成分の存在下でポリイソシアネートと反応させると、親水性であるバイオマス由来ポリオールの成分と疎水性であるポリイソシアネート成分との間に相分離を起こし、均一性が悪く、かつ強度の弱い発泡体になる。また、バイオマス由来ポリオールの成分が全体的に親水性成分であるので、得られた発泡体の吸湿後（高湿度環境下）の寸法の変化が大きく、強度も大きく低下することがある。さらに、発泡体が独立気泡構造になった場合には、セル内外の圧力差により発泡体が変形する傾向がある。
【００３４】
従来の合成系ポリオールから得られる硬質ポリウレタン発泡体と同様な強度物性および形状安定性を得るためには、バイオマス由来ポリオールの発泡の際に発生する相分離を無くすか、または低減すると共に、ポリウレタン骨格に（ポリオール系組成物に）適切な疎水性成分を導入する必要がある。前記の変性反応の際にバイオマス物質の脱水量を３％以上にすることによりバイオマス由来ポリオールとポリイソシアネートとの相溶性を大きく改善できるが、さらに相溶化成分（極性がバイオマス由来ポリオールとポリイソシアネートの間）および発泡体の耐湿気性向上成分として、ポリオール配合成分に、炭素数が３以上のオキシアルキレン基を有するポリエーテルポリオールまたは炭素数が３以上のカルボキシアルキレン基を有するポリエステルポリオールを用いることが有効である。官能基数が３以上のものが強度物性への寄与が大きいので特に好ましい。これらの相溶化ポリオールはバイオマス由来ポリオールとポリイソシアネートとの相溶性を改善し、バイオマス由来ポリオールとポリイソシアネートとの均一な反応を可能にし、発泡体構造の均一性を高め、強度物性を大きく向上させる。また、これら炭素数が３以上のオキシアルキレン基を有するポリエーテルポリオールまたは炭素数が３以上のカルボキシアルキレン基を有するポリエステルポリオールは、親水性が低いので、吸湿後の発泡体の強度および形状を維持する効果がある。これらの相溶化ポリオールの平均分子量は２００〜１０００の範囲であることが好ましい。平均分子量が２００未満であると、水酸基価が高すぎて発泡体の物性バランスが悪くなり、１０００を超えると相溶化剤の効果が低い。
【００３５】
これらの相溶化ポリオールの配合量は、前記ポリオール系組成物において、バイオマス由来ポリオールを除く成分の３０重量％以上、好ましくは４０重量％以上、より好ましくは５０重量％以上であることが好ましい。配合量が、３０重量％未満であると上記の問題点を解決するのに不充分である。
【００３６】
前記相溶化ポリオールの種類は、前記要件を満たせばとくに制限がなく、２種以上混合して用いることもできる。たとえばポリオキシプロピレングリコール、（ポリオキシエチレン）（ポリオキシプロピレン）グリコール、ポリオキシブチレングリコール；グリセリン、トリメチロールプロパン、ペンタエリスリトールなどに、プロピレンオキシド、ε−ポリカプロラクトンなどを反応させたポリオキシプロピレンポリオール、ポリ（カプロラクトン）ポリオールなどが用いられる。具体的には、三洋化成工業（株）製サンニックスＨＤ４０２、ＧＰ１０００、ダイセル化学（株）製ＰＣＬ３０３、三井武田ケミカル（株）製アクトコールＰＥ４５０、ＭＮ１０００などがあげられる。
【００３７】
ポリオール系組成物には、前記相溶化ポリオールのほかに、所要の発泡体の物性、気泡連通化度などに応じて、従来から一般的にポリウレタン発泡体の製造に用いられている鎖延長剤などの低分子ポリオールが配合され得る。たとえばグリセリン、トリメチロールプロパン、トリエタノールアミン、エチレングリコール、ブチレングリコール、ジエチレングリコール、トリメチロールプロパン、ペンタエリスリトールなどがあげられる。さらに、発泡体の気泡連通性、脆性などを制御するために、上記相溶化ポリオール以外の活性水素化合物を添加してもよい。これらの活性水素化合物としては、エタノール、ブタノール、ポリオキシアルキレングリコールモノエーテルなどの１価アルコール；オキシエチレン基を５０重量％以上有するポリエーテルポリオール；分子量が１０００以上の高分子量ポリエーテルポリオールまたはポリエステルポリオール、各種の変性ポリエステルポリオールまたはポリエーテルポリオールなどをあげることができる。また、アクリルポリオール、ヒマシ油あるいはトール油誘導体を用いることもできる。これらのポリオール類の添加量は、バイオマス由来ポリオールを除く成分の０〜６５重量％、好ましくは５〜４０重量％である。添加量が６５重量％を超えるとバイオマス由来ポリオールとポリイソシアネートとの反応均一性が悪くなり、発泡体の強度が低下する傾向がある。
【００３８】
ついで所定量のポリオール系組成物を、適宜アルカリ性物質（中和剤）で中和した後、所定量の整泡剤、触媒および発泡剤を加え、よく混合し、前記水酸基価を考慮して、所定量のポリイソシアネートを加え、一定時間、強く撹拌し、発泡および樹脂化を行う。
【００３９】
また、前記中和剤としては、とくに制限はなく、アルカリ金属またはアルカリ土類金属の水酸化物、さらにはルイス塩基があげられる。詳細には、水酸化ナトリウム、水酸化カリウムなどの無機アルカリ性物質、アミン類などの有機アルカリ性物質があげられる。中和剤の添加量は、ポリオール系組成物のｐＨが４〜９の範囲になるようにすることが好ましい。ｐＨが９を超えると発泡のバランスが悪くなり、発泡体中に空洞などが発生する傾向があり、ｐＨが４未満では、反応速度が遅く、多量の反応触媒を使用しないとバイオマス由来ポリオールが分離し、弱い発泡体となる傾向がある。
【００４０】
発泡工程には、従来から使用されている方法および装置が適用可能であり、ポリオール系組成物とポリイソシアネートから、硬質ポリウレタン発泡体が製造される。スラブ方式、モールド方式、面材との一体成形のいずれの方式も採用され得る。面材との一体形成の場合、ダブルコンベヤー方式で連続パネル形成などの従来の硬質発泡体の成形方法もすべて使用できる。また、原料温度、金型温度、各配合成分の混合方式、混合速度などの発泡条件は、公知のポリウレタン発泡で用いられる条件を採用できる。
【００４１】
添加される整泡剤の種類と量の選択は、発泡体が６５％以上の気泡が連通することができれば特に限定がない。たとえば、（ポリジメチルシロキサン）（ポリオキシアルキレン）共重合ポリエーテルポリオール系の整泡剤が用いられる。整泡剤の添加量は、ポリオール系組成物１００重量部に対して、０．１〜５重量部、好ましくは０．２〜２重量部である。５重量部を超えると効果が変わらないので不必要であるが、０．１重量部未満では、整泡効果が不充分で発泡体が崩壊したり発泡体のセル荒れが発生したりする傾向がある。
【００４２】
反応触媒としては、Ｎ，Ｎ−ジメチルシクロヘキシルアミン、Ｎ−メチルモルフォリン、Ｎ，Ｎ’−ジメチルアミノエタノール、ピリジンなどのモノアミン；Ｎ，Ｎ，Ｎ’， Ｎ’−テトラメチルプロピレンジアミン、ビス（ジメチルアミノエチル）エーテル、トリエチレンジアミン、Ｎ， Ｎ’−ジメチルピペラジン、８−ジアザビシクロ（５，４，０）ウンデセン−７（ＤＢＵ）などのジアミン；Ｎ，Ｎ，Ｎ’，Ｎ”，Ｎ”−ペンタメチルジエチレントリアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラ（３−ジメチルアミノプロピル）メタンジアミンなどのポリアミン；ジブチルスズジアセテート、ジメチルスズメルカプタイド、酢酸カリウム、炭酸カルシウムなどの有機金属化合物や弱酸の塩などの塩基性物質をあげることができる。具体的には、花王（株）製のＫＬ３１、ＫＬ３、日東化成（株）ネオスタンＵ−１００などがあげられる。反応触媒は、１種のみを添加してもよいが、泡化反応と樹脂化反応のバランスおよび発泡体の気泡連通化度を調整するために２種以上を使用することが好ましい。反応触媒の添加量は、ポリオール系組成物１００重量部に対して、０．１〜５重量部である。５重量部を超えると反応が速すぎて発泡体が独立気泡になる傾向があり、０．１重量部未満では、反応速度は不充分で良好な発泡体が得られない傾向がある。
【００４３】
発泡剤としては、環境問題およびバイオマス由来ポリオールとの相溶性を考慮すると水が最も好ましいが、他に従来のポリウレタン発泡に使用されている揮発性有機化合物などを併用または単独で使用してもよい。水の配合量は一般のポリウレタンフォームを製造する場合の常用量でよく、通常、ポリオール系組成物１００重量部に対して１〜１０重量部、好ましくは２〜６重量部である。１０重量部を超えると発泡体の脆性、粉吹性、面材との接着性などの多くの物性が低下する傾向があり、１重量部未満では、ポリオール系組成物の粘度が高く、他の発泡剤を併用しないかぎり充分な発泡が得られない。
【００４４】
ポリイソシアネートとしては、トルエンジイソシアネート（ＴＤＩ）、ジフェニルメタンジイソシアネート（ＭＤＩ）、１，６−ヘキサメチレンジイソシアネート（ＨＤＩ）、２，２，４（２，４，４）−トリメチルヘキサメチレンジイソシアネート（ＴＭＨＤＩ）、ｐ−フェニレンジイソシアネート（ＰＰＤＩ）などのジイソシアネート、ジメチレントリフェニルメタンテトライソシアネート、トリフェニルメタントリイソシアネートなどの多官能イソシアネートのほか、ウレタン変性ＴＤＩ、アロファネート変性ＴＤＩ、ビウレット変性ＴＤＩ、イソシアヌレート変性ＴＤＩなどの変性ＴＤＩ；ウレタン変性ＭＤＩ、カルボジイミド変性ＭＤＩ、ウトニミン変性ＭＤＩなどの変性ＭＤＩ；ＴＤＩ／ＭＤＩ混合物；ＨＤＩ変性物などの変性イソシアネートなどがあげられる。なかでも、硬質発泡体としての物性、コスト、作業環境などを考慮するとＭＤＩが特に好ましい。具体的には、日本ポリウレタン（株）製のミリオネートＭＲ−１００、三井化学（株）製のコスモネートＭ１００、ダウ・ポリウレタン日本（株）製ＰＡＰＩ１３５などがあげられる。ポリイソシアネートの配合量は、ポリオール系組成物の全活性水素基１００モルに対して、ポリイソシアネートのＮＣＯ基が５０〜１８０モル、好ましくは６０〜１５０モル、より好ましくは７０〜１３０モルである。１８０モルを超えると発泡体の連通化度が低下するとともに吸放湿性が極端に落ちる傾向があり、５０重量部未満では、発泡体の強度が不充分となる傾向がある。
【００４５】
本発明で得られる樹脂発泡体の性能をさらに改善するために、発泡および硬化を行う前に、各種の添加剤を添加することができる。たとえば、バイオマス由来ポリオールの粘性、作業性といった溶液物性を改善するための低分子化合物または乳化剤、使用する成分間の混合状態を改善するための乳化剤、ポリイソシアネートとの反応性を改善するための反応ブロック剤（ポリオールに溶解しない溶媒など）、発泡成形材料の着色のための着色剤、発泡成形材料を増量したり、物性を改善したりするための充填剤（フィラー）、発泡成形材料の難燃化を図るための難燃化剤などの添加を行うことができる。
【００４６】
本発明の硬質ポリウレタン発泡体の気泡連通化度は、６５％以上、好ましくは８５％以上、より好ましくは９０％以上である。気泡連通化度は、ＡＳＴＭＤ−２８５６に基づき測定した。
【００４７】
気泡連通化度が６５％未満の場合、発泡体の吸放湿速度、吸湿量、寸法安定性が低下する傾向がある。
【００４８】
本発明の硬質ポリウレタン発泡体の密度は、１０〜２００ｋｇ／ｍ^３、好ましくは２０〜１００ｋｇ／ｍ^３である。密度は、ＪＩＳ−Ａ−９５１１に基づき測定した。密度が２００ｋｇ／ｍ^３を超えると、強度が高くなるだけで特に使用上問題ないが、コスト高となる傾向があり、１０ｋｇ／ｍ^３未満であると、強度物性が低く実用上利用価値が低くなる傾向がある。
【００４９】
本発明の硬質ポリウレタン発泡体の圧縮強度は、２０〜２０００ｋＰａ、好ましくは４０〜１０００ｋＰａである。圧縮強度は、ＪＩＳ−Ａ−９５１１に基づき測定した。圧縮強度が２０００ｋＰａを超えても使用上問題ないが、汎用用途の発泡体はそれほどの強度を必要としない。２０ｋＰａ未満であると、強度が不充分で実用上問題を生じる傾向がある。
【００５０】
本発明の硬質ポリウレタン発泡体の圧縮弾性率は、１ＭＰａ以上、好ましくは２ＭＰａ以上である。圧縮弾性率は、ＪＩＳ−Ａ−９５１１に基づき測定した。圧縮弾性率が１ＭＰａ未満であると、剛性が低く取り扱いにくくなる傾向がある。
【００５１】
発泡体は発泡倍率または発泡体の密度によって強度物性が大きく変わる。すなわち、密度の増大に伴い強度、弾性率も増大するので、単独の強度物性値で発泡体の優劣を判断することができない。従来、非発泡材料の性能を比較するために比強度（強度を密度で除した値）が素材の特性値として使用されているが、発泡体では同一素材を用いても発泡倍率により密度を任意に調整でき、さらに、密度が変わると比強度も変わるので（比強度が密度の増大に伴い増大する）、比強度の値を特性値とすることができない。
【００５２】
本発明者らは、バイオマス由来ポリオールを用いた硬質ウレタン発泡体を中心に多くの硬質ウレタンの密度と圧縮特性との相関関係について検討した。その結果、同一の原料体系・発泡処方から調製した硬質発泡体において、発泡剤の量および密度を変化させても、広い範囲で、圧縮強度または圧縮弾性率を密度の２乗で除した値が定数に近いことを見出した。すなわち、圧縮強度または圧縮弾性率を密度の２乗で除した値が、異なる原料体系または異なる発泡処方で作られる発泡体の特性比較に有用であることを見出した。
【００５３】
便宜上以下のように定義する。
Ｓ_Ｉ＝ｙ／ｘ^２ （式Ｉ）
（ｙは圧縮強度（Ｐａ）、ｘは密度（ｋｇ／ｍ^３）を表す）
Ｓ_ＩＩ＝ｚ／ｘ^２ （式ＩＩ）
（ｚは圧縮弾性率（Ｐａ）、ｘは密度（ｋｇ／ｍ^３）を表す）
【００５４】
本発明の硬質ウレタン発泡体のＳ_Ｉ値は、８０以上、好ましくは１００以上、より好ましくは１２０以上である。Ｓ_Ｉ値が８０未満の場合、従来の石油系硬質ウレタン発泡体と同様に、硬質発泡体として各種の応用分野に要求される強度物性に対応することが困難である。もちろん用途によっては発泡体の密度を増大させて強度を満たすことが可能であるが、コスト高となると共に材料の重量が増加するので、商品価値が低下する。
【００５５】
また、本発明の硬質ウレタン発泡体のＳ_ＩＩ値は、２０００以上、好ましくは２５００以上、より好ましくは３０００以上である。Ｓ_ＩＩ値が２０００未満の場合、多くの用途に要求される物性に対応できないだけではなく、発泡体が柔らかくなり、取り扱いにくくなる傾向がある。
【００５６】
さらに、本発明の硬質ポリウレタン発泡体は、２５℃、相対湿度９０％の条件下での吸湿率が４〜２０％であることが望ましい。従来の石油系発泡体と異なり、環境中の水分を吸収または放出することにより、環境の湿度を調節することが可能となり、硬質ポリウレタン発泡体表面における結露現象を低減することが可能となる。吸湿率が４％未満であると吸湿の効果が小さくなり、吸湿率が２０％を超えると硬質ポリウレタン発泡体の物理的な特性が著しく低下する傾向がある。
【００５７】
さらには、硬質ポリウレタン発泡体が、２５℃、相対湿度３５〜９０％での吸放湿平衡時間Ｔ_１／２が６時間以下であることが、発泡体が通気性、速やかな吸放湿性を有するので好ましい。吸放湿平衡時間がこの範囲にあると、使用環境における温湿度調節が可能になり、硬質ポリウレタン発泡体の周囲の結露防止などが可能になる。
【００５８】
ここで、吸放湿平衡時間Ｔ_１／２を、以下のように定義する。発泡体を１５０×１５０×２５ｍｍのサンプルに裁断し、２５℃、相対湿度３５％の環境で一定重量になるまで放置し、吸・放湿を平衡にする。平衡になった時点での吸湿率を相対湿度３５％での吸湿率（Ｗ_３５％）とする。吸湿率は、発泡体が吸収した水蒸気の重量（吸湿した発泡体の重量と乾燥重量との差）を発泡体の乾燥重量で除した値で重量％として表す。その後、発泡体を２５℃、相対湿度９０％の環境に移し、発泡体の重量が一定になるまで経時変化を記録し（吸湿過程）、吸湿速度および相対湿度９０％での平衡吸湿率Ｗ_９０％を測定する。その後、発泡体を再び２５℃、相対湿度３５％の環境に移し、同様に発泡体重量の経時変化を測定する。Ｗ_９０％を発泡体の吸湿量とし、吸湿過程で発泡体がＷ_３５％から（Ｗ_９０％−Ｗ_３５％）／２の吸湿率に達した時の所要時間を吸湿速度（Ｔａ_１／２）とし、放湿過程で発泡体がＷ_９０％から（Ｗ_９０％−Ｗ_３５％）／２の吸湿率に達した時の所要時間を放湿速度（Ｔｒ_１／２）とする。
【００５９】
図１に本発明の発泡体の代表的な吸放湿の経時変化曲線（吸放湿曲線）を示す。
【００６０】
得られた硬質ポリウレタン発泡体は、断熱材、緩衝材、遮音材などとして、包装材、建材、家具、寝具、自動車部材などに使用され得る。この場合、発泡体の特徴である軽さを保ちながら、多くの用途に対応するために、硬質ポリウレタン発泡体の密度が２０〜１００ｋｇ／ｍ^３、圧縮強度が４０ｋＰａ以上であることが好ましい。畳の緩衝・断熱用芯材または住宅などの床用断熱材として使用する場合は、密度３５〜２００ｋｇ／ｍ^３、圧縮強度２００ｋＰａ以上にすることが望ましい。また、熱伝導率が低いので、断熱材として使用することが可能であり、このような場合は、密度１０〜５０ｋｇ／ｍ^３、圧縮強度５０〜５００ｋＰａであることが望ましい。加えて、本発明の硬質ポリウレタン発泡体からなる芯材を有するラミネートボードや本発明の硬質ポリウレタン発泡体と他の面材とを一体成形したパネルにも応用することができる。ラミネートボードまたはパネルは、天然素材などの通気性を有する材料を、面材として用いることができる。
【００６１】
本発明は、上記のようにバイオマス物質を出発原料として従来の液化手段と発泡手段を利用しつつ、硬質ポリウレタン発泡体を製造することができる。しかも、これを容易かつ安価に製造することができる。
【００６２】
以下、本発明を実施例に基づき説明するが、以下の実施例によって何ら制約を受けるものではない。
【００６３】
【実施例】
製造例１〜５
トウモロコシデンプン（含水率１３％）１１５ｇを、３重量％の硫酸を含むポリエチレングリコール（ＰＥＧ４００）／グリセリン（８０／２０）の混合液１５０ｇと共に、５００ｍｌ容ガラスフラスコに投入し、１５０℃で６０分間反応させた。この反応によりバイオマス由来ポリオール１を得た。また、同様の方法で反応をそれぞれ３０分、８０分、１００分、１２０分間行ない、バイオマス由来ポリオール２〜５を得た。
【００６４】
製造例６
トウモロコシデンプン（含水率１３％）１１５ｇを、２重量％の硫酸を含むε−カプロラクトン／グリセリン（７０／３０）の混合液１５０ｇを用い、製造例１と同様の方法で１００分間反応させた。この反応によりバイオマス由来ポリオール６を得た。
【００６５】
製造例７
トウモロコシデンプン（含水率１３％）１１５ｇを、２重量％の硫酸を含むポリエチレングリコール（ＰＥＧ４００）１５０ｇを用い、製造例１と同様の方法で８０分間反応させた。この反応によりバイオマス由来ポリオール７を得た。
【００６６】
製造例８、９
アカマツ木粉（含水率１５％）１１５ｇを、３重量％の硫酸を含むポリエチレングリコール（ＰＥＧ４００）／グリセリン（８０／２０）の混合液２００ｇを用い、製造例１と同様の方法で８０分間反応させた。この反応によりバイオマス由来ポリオール８を得た。また、反応時間を１２０分に延長し、バイオマス由来ポリオール９を得た。
【００６７】
製造例１０、１１
トウモロコシの皮（含水率６％）１０６．４ｇを、４重量％の硫酸を含むポリエチレングリコール（ＰＥＧ４００）／グリセリン（８０／２０）の混合液２００ｇを用い、製造例１と同様の方法で７０分間反応させた。この反応によりバイオマス由来ポリオール１０を得た。また、反応時間を１２０分に延長し、バイオマス由来ポリオール１１を得た。
【００６８】
製造例１２、１３
アカマツ木粉の代わりに新聞紙（含水率１０％）１１１ｇを使用した以外は製造例８の条件と同様にしてバイオマス由来ポリオール１２を得た。また、硫酸量を４重量％に増やして同反応を行ない、バイオマス由来ポリオール１３を得た。
【００６９】
製造例１４、１５
バガス（含水率４５．２％）１８２．５ｇを３重量％の硫酸を含むポリエチレングリコール（ＰＥＧ４００）／グリセリン（８０／２０）の混合液２００ｇと共に、５００ｍｌ容ガラスフラスコに投入し、１５０℃で８０分間反応させた。この反応によりバイオマス由来ポリオール１４を得た。また、硫酸量を４重量％に増やして同反応を行ない、バイオマス由来ポリオール１５を得た。
【００７０】
【表１】

【００７１】
実施例１〜９
発泡体の調製：バイオマス物質脱水率が３〜２０％であるバイオマス由来ポリオール１、３、４、６、７、８、１０、１２および１４のそれぞれに、水酸化ナトリウム水溶液を添加してｐＨを４〜７に調整した。ポリオールに含まれる水分は発泡剤となるので、その量は予定発泡密度に応じて調整し、発泡用バイオマス由来ポリオールとした。
【００７２】
ついで、これらの発泡用バイオマス由来ポリオールに、相溶化ポリオールとしてアクトコールＰＥ４５０（分子量５００、官能基数４、プロピレンオキシド付加のポリエーテルオール、三井武田ケミカル（株）製）およびアクトコールＭＮ１０００（分子量１０００、官能基数３、プロピレンオキシド付加のポリエーテルポリオール、三井武田ケミカル（株）製）、触媒としてジアミン系触媒（ＫＬ３１、花王（株）製）およびトリアミン系触媒（ＫＬ３、花王（株）製）、整泡剤としてポリオキシアルキレン／ポリジメチルシロキサン コポリマーとアルキルベンゼンとの混合物（ＳＺ１９３２、日本ユニカー（株）製）を、表２に示す処方で添加することにより、ポリオール系組成物を製造した。ポリオール系組成物の全活性水素基１００モルに対してＮＣＯ基１０５モル（イソシアネートインデックス）となるようにＰＡＰＩ１３５（ダウ・ポリウレタン日本（株）製）を混合したのち、攪拌し、発泡体を得た。
【００７３】
得られた発泡体のコア部からサンプリングをし、ＪＩＳ−Ａ−９５１１に基づいて物性を測定した。各バイオマス由来ポリオールの発泡処方および発泡体物性を表２に示す。
【００７４】
表２に示すように、実施例１〜９で得られた発泡体の密度は４０〜４５ｋｇ／ｍ^３であった。使用したバイオマス物質の原料に関わらず、すべての発泡体が優れた強度物性値を示し、密度の影響を加味した評価指標であるＳ_Ｉ値（圧縮強度／密度^２の値）、およびＳ_ＩＩ値（圧縮弾性率／密度^２の値）は実施例５を除いて、それぞれ１２０以上、５０００以上であった。実施例５において、Ｓ_Ｉ値およびＳ_ＩＩ値が少し低い値を示したのは、バイオマス物質の変性反応に用いられたアルコール類が、オキシエチレン基のみからなるＰＥＧ４００であったことが原因と考えられる。しかし、充分に実用的な値であった。また、デンプンポリオール由来発泡体の方が、ほかのバイオマス物質原料由来ポリオールの発泡体よりも高い強度値を示した。発泡体の気泡連通化度については、実施例４を除いて９０％以上の連通化度を有した。実施例４では、バイオマス物質の変性反応に主成分として疎水性であるε−カプロラクトンを用いたので、発泡の際にバイオマス由来ポリオールとポリイソシアネー卜との微小相分離が起こりにくく、独立気泡率の高い発泡体になったと考えられる。
【００７５】
さらに、得られた発泡体を使用して、吸放湿性に関する試験を行ない、発泡体の吸放湿性を評価した。結果を表２に示す。
【００７６】
実施例４の発泡体を除いたデンプン由来発泡体は、１０％前後の吸湿率および速やかな吸放湿速度を有する。実施例４に用いられたバイオマス由来ポリオールはオキシエチレンを含有しない変性溶媒（ε−カプロラクトン）を使用し、かつ、発泡体の気泡連通化度も低いので、吸湿量、吸湿速度とも低かった。
【００７７】
また、木粉・新聞紙由来ポリオールの発泡体は、デンプン由来ポリオールの発泡体より低い吸湿量を示した。
【００７８】
【表２】

【００７９】
実施例１０〜１３
バイオマス由来ポリオール３を用いて、水分量をバイオマス由来ポリオールに対して２．５重量％（実施例１０）、４．５重量％（実施例１１）、５．５重量％（実施例１２）、６．５重量％（実施例１３）に変更し、また、必要に応じてシリコーン整泡剤、ポリイソシアネート量を変更し、発泡体を得た。各バイオマス由来ポリオールの発泡処方および発泡体物性を表３に示す。
【００８０】
表３中、Ｌ５４２１は、整泡剤であるポリオキシアルキレン／ポリジメチルシロキサン コポリマー（日本ユニカー（株）製）を表す。
【００８１】
【表３】

【００８２】
密度の変化に伴って、発泡体の圧縮強度、圧縮弾性率も変化するが、すべての発泡体のＳ_Ｉ値は１２０以上、Ｓ_ＩＩ値は３０００以上であった。気泡連通化度も８５％以上であった。
【００８３】
比較例１〜６
バイオマス物質脱水率が３％未満および２０％以上のバイオマス由来ポリオール２、５、９、１１、１３および１５を使用し、実施例１〜９と同じ操作によりバイオマス由来ポリオールを用いてウレタン発泡体を調整した（比較例１〜６）。発泡処方および発泡体物性を表４に示す。
【００８４】
【表４】

【００８５】
比較例１で用いたバイオマス由来ポリオール２は、変性反応中のバイオマス物質脱水率が１．０６％であることから、バイオマス物質の変性度合いが低く、糖成分がまだ残っていた。そのために、相溶化ポリオールと混合した時点から、糖のような沈殿物が析出した。沈殿物をポリイソシアネートと混合発泡すると，発泡過程中、さらに相分離を起こし、不均一な発泡体になった。また、バイオマス由来ポリオールの水酸基価が高いので、発泡中の発熱量が多く、発泡体の内部に茶色の焼け跡が生じた。得られた発泡体の密度は４５ｋｇ／ｍ^３で実施例１と類似していたが圧縮強度が１８９ｋＰａ、Ｓ_Ｉ値が９３であり、実用的ではあるが実施例１の値と比べるとかなり劣っていた。
【００８６】
比較例２〜６において、得られた発泡体の密度は、脱水量の少ない実施例１〜９のものより低かった。全ての発泡体のＳ_Ｉ値が７０以下であり、実施例１〜９で得られた発泡体のＳ_Ｉの半分程度であった。また、発泡体の色は茶色であり、かなり深く着色した。発泡体の気泡連通化度は６０〜８０％であった。比較例２〜６に用いられたバイオマス由来ポリオールは、変性反応中に、バイオマス物質成分の２０％以上が脱水した。さらに、活性基である水酸基が大きく滅少すると共に、加溶媒分解したバイオマス物質成分が再び縮合し、高分子量のものへと変換した。そのため、ポリオールとしての反応性が大きく低下し、強度の弱い発泡体となったものと推察される。また、バイオマス物質の脱水により発色基が生成されたので、発泡体が大きく着色した。
【００８７】
比較例７〜９
１００重量部のバイオマス由来ポリオール３に対して、バイオマス由来ポリオール以外にほかのポリオールを添加しない条件（比較例７）、ほかのポリオール成分としてＰＥＧ４００（炭素数３以上のオキシアルキレン基を含有しないポリオール）を２０重量部添加する条件（比較例８）、および、ほかのポリオール成分としてＰＥＧ４００とジエチレングリコール（炭素数３以上のオキシアルキレン基を含有しないオキシエチレン系ポリオール）をそれぞれ１０重量部添加する条件（比較例９）で、添加ポリオールを変えた以外は実施例２と同じ方法により発泡体を得た。各バイオマス由来ポリオールの発泡処方および発泡体物性を表４に示す。比較例７では、相溶化ポリオールを添加してないので、発泡の際に相分離を起こし、良好な発泡体が得られなかった。発泡体のＳ_Ｉ値は５５、Ｓ_ＩＩ値は２３８１であり、相溶化ポリオールを添加したものに比べて、かなり悪かった。気泡連通化度も５４％と低かった。
【００８８】
比較例８および９では、バイオマス由来ポリオール以外のポリオールを、実施例１〜９と同じ量添加した。しかし、バイオマス由来ポリオール以外のポリオールがオキシエチレン系であったので、相溶化作用が不充分であり、相分離が起こり、強度物性も実施例の発泡体と比べると悪かった。
【００８９】
実施例１４
実施例１１の発泡処方で、ポリオール組成物を、底部に防水シートを予め引いている５００×５００ｍｍ角、厚さ５０ｍｍの木枠に投入したのち、上面に厚さ３ｍｍの通気性の植物性シートを引いて、プレスで固定し、発泡させ、表面に通気性素材を有するパネル（厚さ５０ｍｍ）を得た。パネルの芯密度が４１ｋｇ／ｍ^３であり、面材付での気泡連通化度が９７％、圧縮強度が３１４ｋＰａであった。面材付で吸湿率Ｗ_９０％が１２．４％、吸湿速度Ｔａ_１／２が５．７時間、放湿速度Ｔｒ_１／２が２．６時間であり、良好な吸放湿性を示した。
【００９０】
発泡体の吸湿性および放湿性を示す図１より、本発明の硬質ポリウレタン発泡体が、高い湿度での吸湿性および低い湿度での除湿性を有することが理解できる。このような性質を有する硬質ポリウレタン発泡体を畳の芯材として利用すると、室内の湿度を快適に調整する機能を有し、発泡体表面の結露を防ぐことができるので、カビの発生を防ぐことができる。
【００９１】
【発明の効果】
本発明によれば、発泡体の強度物性が従来の合成系ポリオール由来の発泡体の強度物性に遜色がなく、かつバイオマス物質の特徴を生かしたバイオマス物質由来のポリウレタン発泡体を提供することができる。
【図面の簡単な説明】
【図１】図１は、バイオマス由来ポリオール１から得られた発泡体の吸湿性および放湿性を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to useful rigid polyurethane foams derived from biomass materials such as wood flour, wood fiber, waste paper, rice hull, rice bran, starch, sugar and the like.
[0002]
[Prior art]
Polyurethane foam is widely used as a heat insulating material, a cushioning material, a sound insulating material, and the like in packaging materials, building materials, furniture, bedding, automobile members, and the like. Recently, interest in the effective use of resources and the global environment has increased, and new urethane raw materials using biomass materials that can reduce the use of fossil resources have been developed.
[0003]
As a raw material of the polyurethane foam, there is a method in which a biomass material such as a lignocellulosic material such as unused material, waste material, or scrap material or a saccharide material such as starch is used. Since most of these biomass materials are solids, a method of pulverizing the biomass material and directly adding it to a polyurethane foam raw material has been disclosed (for example, Patent Document 1, Patent Document 2 and Non-Patent Document 2). 1). However, in these methods, the biomass material basically acts as a simple filler, and has a low effect of reducing petroleum-based foaming raw materials or imparting new functions such as biodegradability to the foam.
[0004]
Furthermore, a method of liquefying a biomass substance by a chemical reaction in the presence of an organic solvent having a hydroxyl group or a latent hydroxyl group such as alcohols or cyclic esters (for example, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 5) Reference 6), and a method of producing a polyurethane foam by reacting the liquefied product with a polyisocyanate as a polyol component has been proposed (for example, see Patent References 7 and 8). In these methods, the solvolyzed biomass material reacts with the isocyanate as a reaction active component (polyol) to form a polyurethane, thereby replacing the conventional petroleum-based polyol. However, liquefied biomass obtained by these techniques has strong hydrophilicity and high viscosity derived from the inherent hydrophilicity and rigid molecular structure of the biomass material. When producing a polyurethane foam from a biomass-derived polyol having high hydrophilicity and high viscosity, it is difficult to mix a basically hydrophobic polyisocyanate with a biomass-derived polyol. For this reason, components are often separated or foaming becomes unstable during reaction molding, and it is difficult to obtain good appearance and physical properties as a molded article. In the case of high foaming, since the physical strength of the foam is low, the foam after foaming shrinks and the shape stability is insufficient.
[0005]
In addition, these techniques aim at simply using biomass-derived polyols instead of petroleum-based polyols, and do not disclose ideas utilizing the features of biomass-derived polyols or such techniques. That is, it does not disclose a technique relating to the development of a function unique to a biomass-derived polyol other than the strength properties of the foam.
[0006]
[Patent Document 1]
JP-B-58-56605
[Patent Document 2]
JP-A-63-284232
[Patent Document 3]
JP-A-2-227434
[Patent Document 4]
JP-A-6-226711
[Patent Document 5]
JP 2000-103864 A
[Patent Document 6]
JP 2002-037867 A
[Patent Document 7]
JP-A-1-36628
[Patent Document 8]
JP-A-6-136168
[Non-patent document 1]
Journal of Applied Polymer Science, 1992, Vol. 144, p. 1477-1483
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of such technical background, and the strength physical properties of the foam are not inferior to the strength physical properties of the conventional synthetic polyol-derived foam, and make use of the characteristics of the biomass material. It is an object of the present invention to provide a polyurethane foam derived from a biomass material.
[0008]
[Means for Solving the Problems]
That is, the present invention relates to a polyurethane foam obtained by reacting a polyol composition containing at least 30% by weight of a biomass-derived polyol with a polyisocyanate, wherein the polyurethane foam has a degree of cell communication of 65%. % Or more and represented by the following formula (I):_I
S_I= Y / x²                                      (Formula I)
(Y is compressive strength (Pa), x is density (kg / m³)
Is 80 or more.
[0009]
The S_IIs preferably 100 or more.
[0010]
The biomass-derived polyol is a modified biomass material obtained by a denaturation reaction between an alcohol or a cyclic ester and a biomass material in the presence of an acid catalyst, and the dehydration rate of the biomass material in the denaturation reaction is 3 to 20. %.
[0011]
The alcohols preferably contain at least 50% by weight of a polyether polyol having an oxyethylene group.
[0012]
In the polyol composition, 30% by weight or more of the component excluding the biomass-derived polyol is a polyether polyol having an oxyalkylene group having 3 or more carbon atoms or a polyester polyol having a carboxyalkylene group having 3 or more carbon atoms. Is preferred.
[0013]
Preferably, the biomass material is a starch or a saccharide.
[0014]
Further, the present invention provides a tatami mat core material made of the rigid polyurethane foam, a heat insulating material, a laminate board having a core material made of the rigid polyurethane foam, and an integral molding of the rigid polyurethane foam and another face material. Related to the panel.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to a rigid polyurethane foam obtained by reacting a polyol-based composition with a polyisocyanate in the presence of a foaming agent, a foam stabilizer, and, if necessary, a catalyst and a filler. The polyol-based composition contains a biomass-derived polyol in an amount of 30% by weight or more, so that the biomass material, which is a recyclable resource, can be effectively used, and the foam has a hydrophilic, biodegradable biomass-derived material. To realize new functions that conventional petroleum-based polyurethane foam does not have. The method for producing the rigid polyurethane foam includes a liquefaction step of modifying a biomass substance into a biomass-derived polyol, and a foaming step of preparing a rigid polyurethane foam from a polyol-based composition containing at least 30% by weight of the biomass-derived polyol. It can be divided into two stages.
[0016]
The polyol composition contains a biomass-derived polyol in an amount of 30% by weight or more, preferably 50 to 90% by weight, more preferably 60 to 80% by weight. When the blending amount of the biomass-derived polyol is less than 30% by weight, the biomass material is not effectively used, and the hygroscopicity of the foam becomes insufficient. When the blending amount exceeds 90% by weight, the phase of the polyol-based composition and the polyisocyanate is not increased. It is difficult to obtain a foam having insufficient solubility and uniform and good physical properties.
[0017]
A conventional method and apparatus for converting a biomass substance into a liquefied substance can be applied to the liquefaction step of preparing a biomass-derived polyol. For example, the methods and apparatuses described in JP-A-4-106128, JP-A-8-225653, and JP-A-11-130873 can be applied. A denaturation reaction of a biomass substance such as lignocellulose or saccharide is performed in the presence of a hydroxyl group or a potential hydroxyl group-containing compound such as a polyol or a cyclic ester, and an acid catalyst to obtain a modified biomass substance. For this reaction, for example, a continuous extrusion liquefaction apparatus or a batch liquefaction apparatus using a single screw extruder or a twin screw extruder can be used.
[0018]
Examples of the biomass substance that can be handled in the present invention include an organic substance based on a living organism that can be converted into an organic material that can be effectively used by humans by any technique. In the present invention, the target biomass material is not particularly limited, but, for example, wood flour, wood fiber, wood chips or crushed wood such as veneer waste, bagasse, plant fiber such as straw and peach, ground pulp (GP), thermomechanical pulp (TMP), paper such as waste paper, lignocellulosic substances such as pulp; cereals such as rice, wheat, corn, potatoes such as potato, sweet potato, and starches as processed products thereof; Further, sugars such as sucrose, glucose and the like can be mentioned. Above all, carbohydrates other than cellulose, such as starch and sugars, have more hydroxyl groups than lignin-containing biomass substances such as wood, have a single component, and are liable to undergo a denaturing reaction. Therefore, a foam having higher strength is obtained, and the obtained foam is particularly preferable because it has less coloring and excellent hygroscopicity. The particle size of the biomass material used as a starting material is not particularly limited, but an arbitrary particle size can be appropriately selected within a range in which the material can be sufficiently liquefied and dissolved in consideration of a liquefaction method, an apparatus, equipment, and the like.
[0019]
In the present invention, the alcohols or cyclic esters used for producing the biomass-derived polyol are not particularly limited, but those having a boiling point of 100 ° C. or more are used in consideration of the convenience of the heating reaction. Is preferred.
[0020]
Examples of the alcohols include aliphatic monohydric alcohols such as pentanol, hexanol, and decanol, ethylene glycol, diethylene glycol, polyoxyethylene glycol (generally, polyethylene glycol, PEG), propylene glycol, and polyoxypropylene glycol (generally, polypropylene glycol, PPG), (polyoxyethylene) (polyoxypropylene) glycol, trimethylene glycol, butylene glycol (alias: 1,4-butanediol), pentamethylene glycol (alias: 1,5-pentanediol), hexamethylene glycol ( Synonyms: 1,6-hexanediol), heptamethylene glycol (alias: 1,7-heptanediol), octamethylene glycol (alias: 1,8-octane) Diol), nonamethylene glycol (alias: 1,9-nonanediol), decamethylene glycol (alias: 1,10-decanediol), dihydric alcohols such as tetramethylethylene glycol (generally pinacol), glycerin, trimethylolpropane , Triethanolamine, 1,2,6-hexanetriol, pentaerythritol, methylglucoside, sorbitol, mannitol, sucrose, etc., or polyols having three or more functional groups such as polyether polyols or polyester polyols starting from these. Is raised. Among them, glycerin, ethylene glycol, polyoxyethylene glycol, polyoxypropylene glycol and the like which are inexpensive and easily available industrially are preferably used.
[0021]
The cyclic esters are not particularly limited, but those which can be polymerized by a ring-opening reaction are preferable. For example, β-propiolactone, β-butyrolactone, α, α′-dimethyl-β- Propiolactone, δ-valerolactone, 1,4-dioxan-2-one, glycolide, ethylene oxalate, propionoxalate, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, γ -Methyl-ε-caprolactone, 4-methyl-7-isopropyl-ε-caprolactone, 3,3,5-trimethyl-ε-caprolactone, lactide and the like. Among them, ε-caprolactone, which is inexpensive, easily available industrially, and easy to liquefy biomass substances, is preferably used.
[0022]
In the denaturation reaction of the biomass substance, the above alcohol or cyclic ester may be used alone, or two or more of them may be used in combination. The use of a mixture is effective in improving the reaction rate or obtaining a biomass-derived polyol having more excellent foaming suitability. In order to impart hydrophilicity to the obtained rigid polyurethane foam, and to facilitate cell communication at the time of foaming, at least 50% by weight or more, preferably 60 to 90% by weight of the total alcohols is used. And a polyether polyol having an oxyethylene group. When the content of the polyether polyol having an oxyethylene group is less than 50% by weight, sufficient moisture absorbing ability cannot be obtained in the foam, and it is difficult to achieve sufficient cell communication. This is presumably because, during the foaming process, microphase separation occurs between the polyoxyethylene chain of the hydrophilic component and the other hydrophobic component, thereby promoting the communication of bubbles. On the other hand, if it exceeds 90% by weight, the biomass-derived polyol has too high hydrophilicity, and the resulting foam has poor moisture resistance and shape stability.
[0023]
The production method and structure of the polyether polyol having an oxyethylene group are not particularly limited, and those obtained by conventional methods can be widely applied, but the molecular weight is preferably in the range of 200 to 1,000. For example, polyoxyethylene glycol having the above-mentioned molecular weight, (polyoxyethylene) (polyoxypropylene) glycol containing 60% or more of oxyethylene units and the like can be mentioned. In this case, for example, those having a molecular weight of less than 200, such as diethylene glycol and triethylene glycol, have insufficient hygroscopicity due to a small amount of ether oxygen capable of forming a hydrogen bond with water. Lack of ability to liquefy substances.
[0024]
In the modification reaction of the biomass material in the present invention, a modifier such as an alcohol or a cyclic ester is added at a ratio of 20 to 1000 parts by weight, preferably 50 to 500 parts by weight, based on 100 parts by weight of the biomass material. If the amount is less than 20 parts by weight, the modification reaction proceeds, but the uniformity of the reaction system is poor and the viscosity of the reaction product is high, so that quality control of the reaction product is difficult. On the other hand, even if the amount exceeds 1000 parts by weight, the denaturation reaction is not hindered, but the efficiency of the process is poor because an excessive amount of the reaction reagent is used.
[0025]
In addition, the biomass-derived polyol referred to in the present invention refers to a reaction product containing a hydroxyl group obtained by a modification reaction between a biomass substance and an alcohol or a cyclic ester. An unreacted alcohol or cyclic ester which does not participate in the biomass material denaturation reaction and coexists with the biomass denatured product after the reaction may be contained. However, in order to increase the content of the component derived from the biomass substance, the excess unreacted alcohol or cyclic ester may be removed by a method such as distillation under reduced pressure.
[0026]
The denaturation reaction (liquefaction reaction) conditions include a reaction temperature of 80 to 200 ° C., preferably 100 to 180 ° C., and a denaturation reaction time of 3 to 60 minutes when using a continuous extrusion type liquefaction apparatus and 10 when using a batch type liquefaction apparatus. To 300 minutes, and can be appropriately selected from them. It is preferable to perform appropriate stirring during the denaturation reaction. By this agitation, torque can be applied to the biomass material to increase the efficiency of the denaturation reaction.
[0027]
The modification reaction in the present invention is preferably performed at normal pressure in the presence of an acid catalyst. Examples of the acid catalyst include inorganic acids, organic acids, and Lewis acids. Among them, for example, sulfuric acid, phosphoric acid, hydrochloric acid, toluenesulfonic acid, phenolsulfonic acid, aluminum chloride, zinc chloride, boron trifluoride, and the like. Is preferred. The amount of the acid catalyst added is 0.05 to 30% by weight, preferably 0.1 to 20% by weight, based on the biomass substance. If the amount exceeds 30% by weight, the biomass substance tends to undergo an excessive reaction such as severe dehydration. If the amount is less than 0.05% by weight, the denaturation reaction is insufficient and tends to remain as a solid. There is.
[0028]
The denaturation reaction is mainly solvolysis of the biomass material, but at the same time, the dehydration and oxidation reaction of the biomass material also occurs. These reactions reduce the hydroxyl groups of the biomass material and reduce the number of reactive groups that react with the polyisocyanate as a polyol. When the dehydration reaction occurs to an appropriate hydroxyl group amount or less, the reactivity of the biomass-derived polyol becomes insufficient, and it becomes difficult to produce a good polyurethane foam. In order to obtain the rigid polyurethane foam of the present invention, it is necessary that the biomass material has a dehydration amount of 3 to 20%. The dehydration rate is calculated by the following equation.

[0029]
The biomass substance reaction rate is determined by filtering and quantifying the unreacted solid biomass substance in the denatured reaction product.
[0030]
The amount of dehydration of the biomass material is preferably 4 to 18%. If the amount of dehydration is 3% or less, the denaturation reaction of the biomass material is insufficient, and a large amount of hydroxyl groups originally contained in the biomass material remains as it is, so that the biomass-derived polyol has a high polarity and other polyol-based compositions. And / or when mixed with a polyisocyanate, components derived from the biomass material may separate or precipitate. In addition, the biomass-derived polyol is separated, and the hydroxyl value is too high, resulting in a brittle foam. On the other hand, when the amount of dehydration exceeds 20%, the hydroxyl value of the biomass-derived polyol is extremely reduced, and the crosslink density of the rigid polyurethane foam is low, so that desired strength cannot be obtained.
[0031]
The hydroxyl value of the obtained biomass-derived polyol is measured by, for example, a phthalic esterification method. A preferred hydroxyl value range is from 250 to 500 mg KOH / g, more preferably from 300 to 450 mg KOH / g. When the hydroxyl value is less than 250 mgKOH / g, the obtained foam has a low crosslinking density and the desired strength tends not to be obtained. When the hydroxyl value exceeds 500 mgKOH / g, the reaction between the biomass-derived polyol and the polyisocyanate tends to fail. The calorific value is large, and defects such as burn marks (scorch) tend to easily occur in the foam.
[0032]
The polyol composition of the present invention contains, in addition to the biomass-derived polyol obtained in the liquefaction step, a compatibilized polyol and the like, a foaming agent, a reaction with a polyisocyanate in the presence of a foam stabilizer, and the like. Is prepared.
[0033]
In general, when a biomass-derived polyol is reacted with a polyisocyanate in the presence of a compounding component of a normal rigid polyurethane foam such as a foaming agent and a foam stabilizer, the component of the biomass-derived polyol that is hydrophilic and the polyisocyanate that is hydrophobic Phase separation occurs with the components, resulting in a foam having poor uniformity and low strength. In addition, since the components of the biomass-derived polyol are hydrophilic components as a whole, the resulting foam has a large change in dimensions after moisture absorption (in a high-humidity environment), and the strength may be greatly reduced. Further, when the foam has a closed cell structure, the foam tends to be deformed due to a pressure difference between the inside and outside of the cell.
[0034]
In order to obtain the same strength physical properties and shape stability as rigid polyurethane foams obtained from conventional synthetic polyols, it is necessary to eliminate or reduce the phase separation that occurs when foaming biomass-derived polyols, and to use a polyurethane skeleton. It is necessary to introduce an appropriate hydrophobic component (to the polyol composition). By making the dehydration amount of the biomass material 3% or more during the above-mentioned modification reaction, the compatibility between the biomass-derived polyol and the polyisocyanate can be greatly improved. As a component for improving the moisture resistance of the foam and the foam, a polyether polyol having an oxyalkylene group having 3 or more carbon atoms or a polyester polyol having a carboxyalkylene group having 3 or more carbon atoms may be used as a polyol compounding component. It is valid. Those having 3 or more functional groups are particularly preferred because they greatly contribute to strength properties. These compatibilized polyols improve the compatibility between the biomass-derived polyol and the polyisocyanate, enable a uniform reaction between the biomass-derived polyol and the polyisocyanate, increase the uniformity of the foam structure, and greatly improve the strength physical properties. . Further, these polyether polyols having an oxyalkylene group having 3 or more carbon atoms or polyester polyols having a carboxyalkylene group having 3 or more carbon atoms have low hydrophilicity, so that the strength and shape of the foam after moisture absorption are maintained. Has the effect of doing The average molecular weight of these compatibilized polyols is preferably in the range of 200 to 1,000. If the average molecular weight is less than 200, the hydroxyl value is too high, and the physical property balance of the foam is deteriorated. If it exceeds 1,000, the effect of the compatibilizer is low.
[0035]
The amount of these compatibilized polyols is preferably at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight of the components other than the biomass-derived polyol in the polyol composition. If the amount is less than 30% by weight, it is insufficient to solve the above problems.
[0036]
The kind of the compatibilized polyol is not particularly limited as long as the requirements are satisfied, and two or more kinds can be used as a mixture. For example, polyoxypropylene glycol, (polyoxyethylene) (polyoxypropylene) glycol, polyoxybutylene glycol; polyoxypropylene polyol obtained by reacting glycerin, trimethylolpropane, pentaerythritol, etc. with propylene oxide, ε-polycaprolactone, etc. And poly (caprolactone) polyol. Specific examples include Sannics HD402 and GP1000 manufactured by Sanyo Kasei Kogyo Co., Ltd., PCL303 manufactured by Daicel Chemical Co., Ltd., and Actcall PE450 and MN1000 manufactured by Mitsui Takeda Chemical Co., Ltd.
[0037]
In addition to the compatibilized polyol, the polyol-based composition may further include a chain extender conventionally used generally in the production of polyurethane foams, depending on the required properties of the foam, the degree of cell communication, and the like. Of low molecular polyols. For example, glycerin, trimethylolpropane, triethanolamine, ethylene glycol, butylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol and the like can be mentioned. Further, an active hydrogen compound other than the above-mentioned compatibilized polyol may be added in order to control the cell openness and brittleness of the foam. Examples of these active hydrogen compounds include monohydric alcohols such as ethanol, butanol and polyoxyalkylene glycol monoether; polyether polyols having 50% by weight or more of oxyethylene groups; high molecular weight polyether polyols or polyester polyols having a molecular weight of 1000 or more. And various modified polyester polyols or polyether polyols. Also, acrylic polyol, castor oil or tall oil derivative can be used. The addition amount of these polyols is 0 to 65% by weight, preferably 5 to 40% by weight of the components excluding the biomass-derived polyol. When the addition amount exceeds 65% by weight, the uniformity of the reaction between the biomass-derived polyol and the polyisocyanate is deteriorated, and the strength of the foam tends to decrease.
[0038]
Next, after a predetermined amount of the polyol composition is appropriately neutralized with an alkaline substance (neutralizing agent), a predetermined amount of a foam stabilizer, a catalyst and a foaming agent are added, mixed well, and in consideration of the hydroxyl value, A predetermined amount of polyisocyanate is added, and the mixture is vigorously stirred for a certain period of time to perform foaming and resinification.
[0039]
The neutralizing agent is not particularly limited, and examples thereof include an alkali metal or alkaline earth metal hydroxide, and a Lewis base. Specifically, inorganic alkaline substances such as sodium hydroxide and potassium hydroxide, and organic alkaline substances such as amines can be mentioned. It is preferable that the amount of the neutralizing agent added is such that the pH of the polyol composition is in the range of 4 to 9. If the pH exceeds 9, the balance of foaming becomes poor, and cavities and the like tend to occur in the foam. If the pH is less than 4, the reaction rate is slow, and if a large amount of reaction catalyst is not used, the polyol derived from biomass is separated. And tend to be a weak foam.
[0040]
A conventionally used method and apparatus can be applied to the foaming step, and a rigid polyurethane foam is produced from the polyol composition and the polyisocyanate. Any of the slab method, the molding method, and the integral molding with the face material can be adopted. In the case of integral formation with the face material, any conventional rigid foam molding method such as continuous panel formation by a double conveyor system can be used. In addition, foaming conditions such as a raw material temperature, a mold temperature, a mixing method of each compounding component, and a mixing speed may be the same as those used for known polyurethane foaming.
[0041]
The type and amount of the foam stabilizer to be added are not particularly limited as long as bubbles of 65% or more can be communicated with the foam. For example, a (polydimethylsiloxane) (polyoxyalkylene) copolymerized polyether polyol-based foam stabilizer is used. The addition amount of the foam stabilizer is 0.1 to 5 parts by weight, preferably 0.2 to 2 parts by weight, based on 100 parts by weight of the polyol composition. If the amount is more than 5 parts by weight, the effect is not changed, and the effect is not changed. However, if the amount is less than 0.1 part by weight, the foam-regulating effect is insufficient and the foam is liable to collapse or the cell of the foam tends to be roughened. is there.
[0042]
Examples of the reaction catalyst include monoamines such as N, N-dimethylcyclohexylamine, N-methylmorpholine, N, N′-dimethylaminoethanol and pyridine; N, N, N ′, N′-tetramethylpropylenediamine, bis ( Dimethylaminoethyl) ether, triethylenediamine, N, N'-dimethylpiperazine, diamine such as 8-diazabicyclo (5,4,0) undecene-7 (DBU); N, N, N ', N ", N"- Polyamines such as pentamethyldiethylenetriamine and N, N, N ', N'-tetra (3-dimethylaminopropyl) methanediamine; organometallic compounds such as dibutyltin diacetate, dimethyltin mercaptide, potassium acetate and calcium carbonate; and weak acids And basic substances such as salts thereof. Specific examples include KL31 and KL3 manufactured by Kao Corporation, and Neostan U-100 by Nitto Kasei Corporation. Although only one type of reaction catalyst may be added, it is preferable to use two or more types in order to adjust the balance between the foaming reaction and the resinification reaction and to adjust the degree of cell communication of the foam. The addition amount of the reaction catalyst is 0.1 to 5 parts by weight based on 100 parts by weight of the polyol composition. If the amount is more than 5 parts by weight, the reaction is too fast and the foam tends to be closed cells. If the amount is less than 0.1 part by weight, the reaction rate is insufficient and a good foam tends not to be obtained.
[0043]
As the foaming agent, water is most preferable in consideration of environmental problems and compatibility with the biomass-derived polyol, but volatile organic compounds and the like used in conventional polyurethane foaming may be used in combination or alone. . The mixing amount of water may be a usual amount when a general polyurethane foam is produced, and is usually 1 to 10 parts by weight, preferably 2 to 6 parts by weight based on 100 parts by weight of the polyol composition. When the amount exceeds 10 parts by weight, many physical properties such as brittleness of the foam, powder blowing property, and adhesion to the face material tend to decrease. When the amount is less than 1 part by weight, the viscosity of the polyol composition is high, and Unless a foaming agent is used in combination, sufficient foaming cannot be obtained.
[0044]
Examples of the polyisocyanate include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), 2,2,4 (2,4,4) -trimethylhexamethylene diisocyanate (TMHDI), p -In addition to diisocyanates such as phenylene diisocyanate (PPDI), polyfunctional isocyanates such as dimethylenetriphenylmethanetetraisocyanate and triphenylmethanetriisocyanate, and modifications such as urethane-modified TDI, allophanate-modified TDI, biuret-modified TDI, and isocyanurate-modified TDI. TDI; Modified MDI such as urethane-modified MDI, carbodiimide-modified MDI, and urtonimine-modified MDI; TDI / MDI mixture; Modification such as HDI-modified Such as isocyanate, and the like. Among them, MDI is particularly preferable in consideration of physical properties, cost, working environment, and the like as a rigid foam. Specific examples include Millionate MR-100 manufactured by Nippon Polyurethane Co., Ltd., Cosmonate M100 manufactured by Mitsui Chemicals, Inc., and PAPI135 manufactured by Dow Polyurethane Japan Co., Ltd. The compounding amount of the polyisocyanate is such that the NCO group of the polyisocyanate is 50 to 180 mol, preferably 60 to 150 mol, more preferably 70 to 130 mol, based on 100 mol of all active hydrogen groups of the polyol composition. If the amount exceeds 180 mol, the degree of communication of the foam tends to decrease, and the moisture absorption / desorption tends to decrease extremely. If the amount is less than 50 parts by weight, the strength of the foam tends to be insufficient.
[0045]
In order to further improve the performance of the resin foam obtained in the present invention, various additives can be added before foaming and curing. For example, a low molecular compound or an emulsifier for improving the solution physical properties such as viscosity and workability of a biomass-derived polyol, an emulsifier for improving a mixing state between components used, and a reaction for improving reactivity with a polyisocyanate. Blocking agents (solvents that do not dissolve in polyols), coloring agents for coloring foam molding materials, fillers for increasing the amount of foam molding materials and improving physical properties, flame retardancy of foam molding materials For example, a flame retardant or the like can be added for the purpose of attaining the effect.
[0046]
The rigid polyurethane foam of the present invention has a cell opening degree of 65% or more, preferably 85% or more, more preferably 90% or more. The bubble communication degree was measured based on ASTM D-2856.
[0047]
If the degree of cell communication is less than 65%, the moisture absorption / desorption rate, moisture absorption, and dimensional stability of the foam tend to decrease.
[0048]
The rigid polyurethane foam of the present invention has a density of 10 to 200 kg / m.³, Preferably 20 to 100 kg / m³It is. The density was measured based on JIS-A-9511. 200kg / m density³When it is more than 10 kg / m, the strength tends to be high and there is no problem in use, but the cost tends to be high.³If it is less than 3, strength physical properties tend to be low and practical use value tends to be low.
[0049]
The compressive strength of the rigid polyurethane foam of the present invention is 20 to 2000 kPa, preferably 40 to 1000 kPa. The compressive strength was measured based on JIS-A-9511. Even if the compressive strength exceeds 2000 kPa, there is no problem in use, but the foam for general use does not require such a high strength. If it is less than 20 kPa, the strength tends to be insufficient, and there is a tendency to cause problems in practical use.
[0050]
The compression elastic modulus of the rigid polyurethane foam of the present invention is 1 MPa or more, preferably 2 MPa or more. The compression modulus was measured based on JIS-A-9511. If the compression modulus is less than 1 MPa, the rigidity tends to be low, making it difficult to handle.
[0051]
The strength properties of the foam vary greatly depending on the expansion ratio or the density of the foam. That is, since the strength and the elastic modulus also increase with the increase in the density, it is not possible to judge the superiority or the inferiority of the foam from a single strength physical property value. Conventionally, specific strength (value obtained by dividing strength by density) has been used as a characteristic value of a material in order to compare the performance of non-foamed materials. In addition, the specific intensity changes when the density changes (the specific intensity increases with the increase in the density), so that the value of the specific intensity cannot be used as the characteristic value.
[0052]
The present inventors have studied the correlation between the density and compression characteristics of many hard urethanes, mainly on hard urethane foams using biomass-derived polyols. As a result, in a rigid foam prepared from the same raw material system and foaming formula, even when the amount and density of the blowing agent are changed, the value obtained by dividing the compressive strength or compressive modulus by the square of the density over a wide range is obtained. We found that it was close to a constant. That is, it has been found that a value obtained by dividing the compressive strength or compressive modulus by the square of the density is useful for comparing the properties of foams made with different raw material systems or different foaming formulations.
[0053]
For convenience, it is defined as follows.
S_I= Y / x²                                      (Formula I)
(Y is compressive strength (Pa), x is density (kg / m³)
S_II= Z / x²                                      (Formula II)
(Z is the compression modulus (Pa), x is the density (kg / m³)
[0054]
S of the rigid urethane foam of the present invention_IThe value is at least 80, preferably at least 100, more preferably at least 120. S_IWhen the value is less than 80, it is difficult to cope with the strength physical properties required for various application fields as a rigid foam, similarly to a conventional petroleum-based rigid urethane foam. Of course, depending on the application, it is possible to satisfy the strength by increasing the density of the foam, but the cost increases and the weight of the material increases, so that the commercial value decreases.
[0055]
In addition, the rigid urethane foam of the present invention has an S_IIThe value is at least 2,000, preferably at least 2,500, more preferably at least 3,000. S_IIIf the value is less than 2,000, not only physical properties required for many applications cannot be met, but also the foam tends to be soft and difficult to handle.
[0056]
Furthermore, the rigid polyurethane foam of the present invention desirably has a moisture absorption of 4 to 20% under the conditions of 25 ° C. and a relative humidity of 90%. Unlike conventional petroleum-based foams, by absorbing or releasing moisture in the environment, it is possible to adjust the humidity of the environment and reduce the condensation phenomenon on the surface of the rigid polyurethane foam. If the moisture absorption is less than 4%, the effect of moisture absorption is reduced, and if the moisture absorption is more than 20%, the physical properties of the rigid polyurethane foam tend to be significantly reduced.
[0057]
In addition, the rigid polyurethane foam has a moisture absorption / release equilibrium time T at 25 ° C. and a relative humidity of 35 to 90%._1/2Is preferably 6 hours or less, since the foam has air permeability and rapid moisture absorption / release properties. When the moisture absorption / release equilibrium time is within this range, temperature and humidity can be adjusted in the use environment, and dew condensation around the rigid polyurethane foam can be prevented.
[0058]
Here, the moisture absorption / desorption equilibrium time T_1/2Is defined as follows. The foam is cut into a sample of 150 × 150 × 25 mm and left to stand at a constant weight in an environment of 25 ° C. and 35% relative humidity to equilibrate absorption and desorption. When the equilibrium is reached, the moisture absorption at the relative humidity of 35% (W_35%). The moisture absorption is expressed as a weight% as a value obtained by dividing the weight of the water vapor absorbed by the foam (the difference between the weight of the moisture absorbed foam and the dry weight) by the dry weight of the foam. Thereafter, the foam was transferred to an environment at 25 ° C. and a relative humidity of 90%, and a change with time was recorded until the weight of the foam became constant (moisture absorption process)._90%Is measured. Thereafter, the foam is again transferred to an environment at 25 ° C. and a relative humidity of 35%, and the change over time in the weight of the foam is similarly measured. W_90%Is the moisture absorption of the foam, and the foam absorbs W during the moisture absorption process._35%From (W_90%-W_35%) / 2, the required time when the moisture absorption rate is reached is determined by the moisture absorption rate (Ta_1/2), And the foam becomes W_90%From (W_90%-W_35%) / 2 when the moisture absorption rate is reached,_1/2).
[0059]
FIG. 1 shows a typical time-dependent change curve of moisture absorption / desorption (moisture absorption / desorption curve) of the foam of the present invention.
[0060]
The obtained rigid polyurethane foam can be used as a heat insulating material, a cushioning material, a sound insulating material and the like for packaging materials, building materials, furniture, bedding, automobile members and the like. In this case, the rigid polyurethane foam has a density of 20 to 100 kg / m2 in order to cope with many applications while maintaining the lightness which is a characteristic of the foam.³The compressive strength is preferably 40 kPa or more. When used as cushioning / insulation core material for tatami mats or as floor insulation material for houses, the density is 35 to 200 kg / m.³The compression strength is desirably 200 kPa or more. Further, since the thermal conductivity is low, it can be used as a heat insulating material. In such a case, the density is 10 to 50 kg / m.³The compression strength is desirably 50 to 500 kPa. In addition, the present invention can be applied to a laminate board having a core made of the rigid polyurethane foam of the present invention, and a panel in which the rigid polyurethane foam of the present invention and another face material are integrally formed. For the laminate board or panel, a material having air permeability such as a natural material can be used as a face material.
[0061]
According to the present invention, a rigid polyurethane foam can be produced using a biomass material as a starting material and utilizing conventional liquefaction means and foaming means as described above. Moreover, it can be manufactured easily and inexpensively.
[0062]
Hereinafter, the present invention will be described based on examples, but the present invention is not limited by the following examples.
[0063]
【Example】
Production Examples 1 to 5
115 g of corn starch (water content: 13%) was put into a 500 ml glass flask together with 150 g of a mixed solution of polyethylene glycol (PEG400) / glycerin (80/20) containing 3% by weight of sulfuric acid, and reacted at 150 ° C. for 60 minutes. I let it. The biomass-derived polyol 1 was obtained by this reaction. Further, the reaction was carried out in the same manner for 30 minutes, 80 minutes, 100 minutes, and 120 minutes, respectively, to obtain biomass-derived polyols 2 to 5.
[0064]
Production Example 6
115 g of corn starch (water content: 13%) was reacted for 100 minutes in the same manner as in Production Example 1, using 150 g of a mixed solution of ε-caprolactone / glycerin (70/30) containing 2% by weight of sulfuric acid. By this reaction, biomass-derived polyol 6 was obtained.
[0065]
Production Example 7
115 g of corn starch (water content: 13%) was reacted with 150 g of polyethylene glycol (PEG400) containing 2% by weight of sulfuric acid for 80 minutes in the same manner as in Production Example 1. By this reaction, biomass-derived polyol 7 was obtained.
[0066]
Production Examples 8 and 9
115 g of Japanese red pine wood flour (water content 15%) was reacted for 80 minutes in the same manner as in Production Example 1 using 200 g of a mixed solution of polyethylene glycol (PEG400) / glycerin (80/20) containing 3% by weight of sulfuric acid. Was. By this reaction, biomass-derived polyol 8 was obtained. In addition, the reaction time was extended to 120 minutes to obtain biomass-derived polyol 9.
[0067]
Production Examples 10 and 11
Using 106.4 g of corn hull (water content: 6%) and 200 g of a mixed solution of polyethylene glycol (PEG400) / glycerin (80/20) containing 4% by weight of sulfuric acid for 70 minutes in the same manner as in Production Example 1 Reacted. The biomass-derived polyol 10 was obtained by this reaction. In addition, the reaction time was extended to 120 minutes to obtain biomass-derived polyol 11.
[0068]
Production Examples 12 and 13
Biomass-derived polyol 12 was obtained in the same manner as in Production Example 8, except that 111 g of newsprint (water content: 10%) was used instead of red pine wood flour. The same reaction was carried out by increasing the amount of sulfuric acid to 4% by weight to obtain a biomass-derived polyol 13.
[0069]
Production Examples 14 and 15
182.5 g of bagasse (water content: 45.2%) was put into a 500 ml glass flask together with 200 g of a mixed solution of polyethylene glycol (PEG400) / glycerin (80/20) containing 3% by weight of sulfuric acid, and charged at 150 ° C. Allowed to react for minutes. The biomass-derived polyol 14 was obtained by this reaction. The same reaction was carried out by increasing the amount of sulfuric acid to 4% by weight to obtain a biomass-derived polyol 15.
[0070]
[Table 1]

[0071]
Examples 1 to 9
Preparation of foam: A biomass-derived polyol having a biomass material dehydration rate of 3 to 20% is added to each of the biomass-derived polyols 1, 3, 4, 6, 7, 8, 10, 12, and 14 by adding an aqueous sodium hydroxide solution to adjust the pH. Adjusted to 4-7. Since the water contained in the polyol serves as a foaming agent, the amount was adjusted according to the expected foaming density to obtain a biomass-derived polyol for foaming.
[0072]
Next, Actcoal PE450 (molecular weight: 500, functional group: 4, polyetherol with propylene oxide added, manufactured by Mitsui Takeda Chemical Co., Ltd.) and Actokol MN1000 (molecular weight: 1,000, A polyether polyol having 3 functional groups and propylene oxide added, manufactured by Mitsui Takeda Chemical Co., Ltd .; diamine-based catalysts (KL31, manufactured by Kao Corporation) and triamine-based catalysts (KL3, manufactured by Kao Corporation) as catalysts; As a foaming agent, a mixture of a polyoxyalkylene / polydimethylsiloxane copolymer and an alkylbenzene (SZ1932, manufactured by Nippon Unicar Co., Ltd.) was added according to the formulation shown in Table 2, thereby producing a polyol composition. After mixing PAPI135 (manufactured by Dow Polyurethane Nippon Co., Ltd.) such that the NCO group becomes 105 mol (isocyanate index) with respect to 100 mol of all active hydrogen groups of the polyol composition, the mixture was stirred to obtain a foam. .
[0073]
Sampling was performed from the core of the obtained foam, and physical properties were measured based on JIS-A-9511. Table 2 shows the foaming formulation and foam properties of each biomass-derived polyol.
[0074]
As shown in Table 2, the density of the foam obtained in Examples 1 to 9 was 40 to 45 kg / m.³Met. Regardless of the raw material of the biomass material used, all the foams show excellent strength physical property values, and are evaluation indices taking into account the influence of density._IValue (compression strength / density²), And S_IIValue (compression modulus / density²) Were 120 or more and 5000 or more, respectively, except for Example 5. In Example 5, S_IValue and S_IIIt is considered that the reason why the value was slightly lower is that the alcohol used for the denaturation reaction of the biomass substance was PEG400 consisting of only oxyethylene groups. However, it was a sufficiently practical value. Further, the foam derived from starch polyol showed higher strength value than the foam derived from polyol derived from other biomass material raw materials. Except for Example 4, the foam had a degree of communication of 90% or more, except for Example 4. In Example 4, since ε-caprolactone, which is hydrophobic, was used as a main component in the denaturation reaction of the biomass material, microphase separation between the biomass-derived polyol and the polyisocyanate hardly occurred during foaming, and the closed cell rate was low. It is considered that the foam had a high density.
[0075]
Further, using the obtained foam, a test on moisture absorption / release properties was performed to evaluate the moisture absorption / release properties of the foam. Table 2 shows the results.
[0076]
The starch-derived foam excluding the foam of Example 4 has a moisture absorption rate of about 10% and a rapid moisture absorption / release rate. The biomass-derived polyol used in Example 4 used a modified solvent (ε-caprolactone) containing no oxyethylene and had a low degree of cell communication of the foam, so that both the moisture absorption rate and the moisture absorption rate were low.
[0077]
Further, the foam of the polyol derived from wood flour / newspaper showed a lower moisture absorption than the foam of the polyol derived from starch.
[0078]
[Table 2]

[0079]
Examples 10 to 13
Using the biomass-derived polyol 3, the water content was 2.5% by weight (Example 10), 4.5% by weight (Example 11), 5.5% by weight (Example 12), based on the biomass-derived polyol. The amount was changed to 6.5% by weight (Example 13), and if necessary, the amounts of the silicone foam stabilizer and the polyisocyanate were changed to obtain a foam. Table 3 shows the foaming formulation and foam properties of each biomass-derived polyol.
[0080]
In Table 3, L5421 represents a polyoxyalkylene / polydimethylsiloxane copolymer (manufactured by Nippon Unicar Co., Ltd.) as a foam stabilizer.
[0081]
[Table 3]

[0082]
As the density changes, the compressive strength and compressive modulus of the foam also change._IValue is 120 or more, S_IIThe value was 3000 or more. The bubble communication degree was also 85% or more.
[0083]
Comparative Examples 1 to 6
Using biomass-derived polyols 2, 5, 9, 11, 13 and 15 having a biomass material dehydration rate of less than 3% and 20% or more, a urethane foam is produced using the biomass-derived polyol by the same operation as in Examples 1 to 9. It was adjusted (Comparative Examples 1 to 6). Table 4 shows the foaming formulation and foam properties.
[0084]
[Table 4]

[0085]
Since the biomass-derived polyol 2 used in Comparative Example 1 had a biomass substance dehydration rate of 1.06% during the modification reaction, the degree of denaturation of the biomass substance was low, and the sugar component still remained. For this reason, a precipitate such as sugar was precipitated from the time of mixing with the compatibilized polyol. When the precipitate was mixed and foamed with the polyisocyanate, further phase separation occurred during the foaming process, resulting in an uneven foam. In addition, since the hydroxyl value of the biomass-derived polyol was high, the calorific value during foaming was large, and brown burn marks occurred inside the foam. The density of the obtained foam is 45 kg / m³And the compression strength was 189 kPa,_IThe value was 93, which was practical but considerably inferior to the value of Example 1.
[0086]
In Comparative Examples 2 to 6, the densities of the obtained foams were lower than those of Examples 1 to 9 having a small amount of dehydration. S for all foams_IValue is 70 or less, and S of the foam obtained in Examples 1 to 9_IWas about half of Also, the color of the foam was brown, and it was considerably deeply colored. The degree of cell communication of the foam was 60 to 80%. In the biomass-derived polyol used in Comparative Examples 2 to 6, 20% or more of the biomass substance component was dehydrated during the modification reaction. Further, the hydroxyl group, which is an active group, was greatly reduced, and the solvolyzed biomass substance component was condensed again and converted to a high molecular weight substance. Therefore, it is presumed that the reactivity as the polyol was greatly reduced, and the foam had low strength. In addition, since the coloring group was generated by dehydration of the biomass substance, the foam was greatly colored.
[0087]
Comparative Examples 7 to 9
Conditions for 100 parts by weight of biomass-derived polyol 3 in which no other polyol was added other than the biomass-derived polyol (Comparative Example 7), PEG400 (polyol containing no oxyalkylene group having 3 or more carbon atoms) as another polyol component (Comparative Example 8) and 10 parts by weight of PEG400 and diethylene glycol (an oxyethylene-based polyol containing no oxyalkylene group having 3 or more carbon atoms) as other polyol components (Comparative Example 8). A foam was obtained in the same manner as in Example 2 except that the added polyol was changed in Example 9). Table 4 shows the foaming formulation and foam properties of each biomass-derived polyol. In Comparative Example 7, since no compatibilizing polyol was added, phase separation occurred during foaming, and a good foam was not obtained. Foam S_IValue is 55, S_IIThe value was 2381, which was considerably worse than that in which the compatibilizing polyol was added. The degree of bubble communication was as low as 54%.
[0088]
In Comparative Examples 8 and 9, polyols other than the biomass-derived polyol were added in the same amounts as in Examples 1 to 9. However, since the polyols other than the biomass-derived polyol were oxyethylene-based, the compatibilizing action was insufficient, phase separation occurred, and the strength properties were poorer than those of the foams of Examples.
[0089]
Example 14
In the foaming formulation of Example 11, the polyol composition was put into a wooden frame of 500 × 500 mm square and 50 mm thick with a waterproof sheet previously drawn on the bottom, and then a 3 mm thick breathable vegetable sheet on the top. Was pulled, fixed with a press, and foamed to obtain a panel (thickness: 50 mm) having a breathable material on the surface. Panel core density 41kg / m³The degree of bubble communication with the face material was 97%, and the compressive strength was 314 kPa. With surface material, moisture absorption W_90%Is 12.4%, moisture absorption rate Ta_1/2Is 5.7 hours, moisture release rate Tr_1/2Was 2.6 hours, indicating good moisture absorption / release properties.
[0090]
From FIG. 1 showing the hygroscopicity and moisture release of the foam, it can be understood that the rigid polyurethane foam of the present invention has hygroscopicity at high humidity and dehumidification at low humidity. When a rigid polyurethane foam having such properties is used as a core material of a tatami mat, it has a function of adjusting indoor humidity comfortably and can prevent dew condensation on the foam body surface. Can be.
[0091]
【The invention's effect】
According to the present invention, it is possible to provide a polyurethane foam derived from a biomass material that has the same strength physical properties as a conventional synthetic polyol-derived foam, and that makes use of the characteristics of a biomass material. .
[Brief description of the drawings]
FIG. 1 shows the hygroscopicity and the moisture release of a foam obtained from a biomass-derived polyol 1.

Claims (10)

A polyurethane-based foam obtained by reacting a polyol-based composition containing at least 30% by weight of a biomass-derived polyol with a polyisocyanate, wherein the polyurethane-based foam has a cell communication degree of 65% or more, and _{S I} represented by the following (formula I)
S _I = y / x ² (formula I)
(Y represents compressive strength (Pa), x represents density (kg / m ³ ))
Is 80 or more. Rigid polyurethane foam of claim 1 wherein S _I is 100 or more. The biomass-derived polyol is a modified biomass material obtained by a denaturation reaction between an alcohol or a cyclic ester and a biomass material in the presence of an acid catalyst, and the dehydration rate of the biomass material in the denaturation reaction is 3 to 20. % Of the rigid polyurethane foam according to claim 1. The rigid polyurethane foam according to claim 3, wherein the alcohol contains at least 50% by weight of a polyether polyol having an oxyethylene group. In the polyol composition, 30% by weight or more of the component excluding the biomass-derived polyol is a polyether polyol having an oxyalkylene group having 3 or more carbon atoms or a polyester polyol having a carboxyalkylene group having 3 or more carbon atoms. The rigid polyurethane foam according to claim 1, 2, 3, or 4. The rigid polyurethane foam according to claim 3, wherein the biomass substance is a starch or a saccharide. A tatami core comprising the rigid polyurethane foam according to claim 1, 2, 3, 4, 5 or 6. A heat insulating material comprising the rigid polyurethane foam according to claim 1, 2, 3, 4, 5, or 6. A laminate board having a core material comprising the rigid polyurethane foam according to claim 1, 2, 3, 4, 5, or 6. A panel in which the rigid polyurethane foam according to claim 1, 2, 3, 4, 5, or 6 and another face material are integrally formed.

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