JP3554380B2 - Method for producing polyurethane foam - Google Patents

Description

【０００８】
しかしながら、ｏ−位にヒドロキシメチル基を有するフェノール樹脂であるノボラック系フェノール樹脂は、一般に固体で溶媒に不溶であることからポリオール成分としての使用は困難であり、又、同様のレゾール系フェノール樹脂は、通常２０％以上の水分を有しており、ポリオールとして使用すると多量の水がイソシアネートと反応してしまい、反応を制御することが困難となる。更に、含水率を低下させると樹脂粘度が上昇し、撹拌効率の低下などを引きおこす。そこで本発明の発明者らは、フェノール樹脂の中でも例えば含水率０．５％以下で粘度１０００〜２００００ｃｐのベンジリックエ−テル型フェノール樹脂に注目して実験を重ねた結果、このフェノール樹脂がポリウレタンフォーム製造おけるポリオール成分として使用できることを見い出した。
【０００９】
ところが、ベンジリックエーテル型フェノール樹脂のヒドロキシメチル基と有機イソシアネートとの反応から生ずる炭酸ガスだけでは発泡が不充分であり、所望する低密度（高発泡度）の発泡体を得ることができなかった。そこで、本発明の発明者らは、更に検討を行った結果、水を発泡助剤として加え、更に水とイソシアネートとの反応を促進させるために三級アミン系泡化触媒を加えることにより、上記反応式Ａに示される反応に加えて、下記反応式Ｂで示されるウレア結合形成に伴う炭酸ガス発生反応も利用でき、目的とする低密度のポリウレタン発泡体を製造しうることを見い出し、本発明を完成するに至ったものである。
【化２】

【００１０】
以下に本発明を詳細に説明する。
【００１１】
本発明は、ポリウレタン発泡体の製造に必須のポリオール成分の少なくとも一部として、ヒドロキシメチル基を有するベンジリックエーテル型フェノール樹脂を使用する点に特徴があり、ここで前記「ヒドロキシメチル基を有するベンジリックエーテル型フェノール樹脂」とは、フェノールとアルデヒドとを、例えば二価金属のナフテン酸塩、カルボン酸塩等からなる触媒を用いてｌ００〜ｌ３０℃の温度で反応させることによって得られるフェノール樹脂の一種であり、重合条件により粘調な液体から半固体、固体に至る範囲までその性状を変えることができるものをいい、例えば、特公昭４７−５０８７３号公報に記載された方法に準じて製造することができるものである。
【００１２】
そのようなヒドロキシメチル基を有するベンジリックエーテル型フェノール樹脂（以下、この明細書では単にベンジリックエーテル型フェノール樹脂と表すことがある）は、水酸基価に換算して例えば３００〜７００ｍｇＫＯＨ／ｇ、好ましくは４５０〜６００ｍｇＫＯＨ／ｇの範囲内でポリオ−ル成分の一部として含有することができる。
【００１３】
本発明において、上記ベンジリックエーテル型フェノール樹脂は、前記ポリオール成分として単独で使用することもできるが、単独で使用すると硬化速度が速くなりすぎ、形成される発泡体の内部に亀裂等が生じやすくなることもあるので、一般には他のポリオールと併用することが好ましい。併用しうる他のポリオールとしては、従来からポリウレタンの製造に際して使用されているものが本発明においても同様に使用可能であり、例えば、エチレングリコール、ジエチレングリコール、ネオペンチルグリコール、ｌ，４−ブタンジオール、ｌ，６−ヘキサンジオール、ｌ，４−シクロヘキサンジメタノール等の二価アルコール；グリセリン、トリメチロールプロパン、トリス（２−ヒドロキシエチル）イソシアヌレート、ペンタエリストール等の三価以上のアルコール；又はこれらから得られるポリエステルポリオール、ポリエーテルポリオール、エチレンジアミン系ポリオールやエーテル系マンニッヒポリオール等を挙げることができる。
【００１４】
ベンジリックエーテル型フェノール樹脂以外の上記他のポリオールは、単独で使用することができ、或いは２種類以上組み合わせて用いてもよく、特にエチレンジアミン系ポリオール、エーテル系マンニッヒポリオールが好適である。
【００１５】
尚、これら他のポリオールをベンジリックエーテル型フェノール樹脂と併用する場合、ベンジリックエーテル型フェノール樹脂の使用量は、厳密に制限されるものではなく、形成される発泡体に望まれる物性、併用する他のポリオールの種類等に応じて広範にわたり変更することができるが、ポリオールの合計量を基準にして通常２０〜ｌ００重量％、特に３０〜８０重量％の節囲内で用いるのが好都合である。
【００１６】
一方、上記ポリオール成分と反応する有機ポリイソシアネート成分としては、従来からポリウレタンの製造に際し使用されている、イソシアネート基（−ＮＣＯ）をｌ分子中に２個以上含有する脂肪族系、脂環式系、芳香族系、芳香−脂肪族系等のポリイソシアネート化合物を挙げることができ、例えば２，４−トリレンジイソシアネート、２，６−トリレンジイソシアネート、２，４−トリレンジイソシアネートと２，６−トリレンジイソシアネートの混合物、粗トリレンジイソシアネート、メチレンジフェニルジイソシアネート（ＭＤＩ）、４，４’，４”−トリフェニルメチレントリイソシアネート、ポリメチレンポリフェニルイソシアネート（粗ＭＤＩ）等の芳香族ポリイソシアート；ヘキサメチレン−１，６−ジイソシアネート、水添ＭＤＩ等の脂肪族ポリイソシアネート等が挙げられ、これらの中でも特に粗ＭＤＩが好適である。
【００１７】
上記有機ポリイソシアネート成分の前記ポリオール成分に対する使用割合は、ＮＣＯ／ＯＨ当量でｌ．０〜ｌ．５という範囲を好適なものとして例示することができる。
【００１８】
本発明においては、前記ベンジリックエーテル型フェノール樹脂のヒドロキシメチル基と、有機ポリイソシアネート成分のイソシアネート基との反応を促進するために、有機錫系ウレタン化触媒を使用する。この有機錫系ウレタン化触媒としては、ウレタン化反応に一般に使用されているものが使用可能であり、例えば、ジブチル錫ジラウレート、ジブチル錫ジアセテート、ジブチル錫ジアルキルマレート、ステアリン酸錫、オクチル酸錫等が挙げられる。これら有機錫系ウレタン化触媒の使用量は特に制限されるものではないが、使用するベンジリックエーテル型フェノール樹脂の合計量を基準にして通常０．ｌ〜ｌ４重量％、特に０．４〜９重量％の範囲内で用いるのが適当である。
【００１９】
又、本発明においては、水−イソシアネートの反応を促進するために、三級アミン系泡化触媒を使用する。尚、泡化触媒とは、触媒を添加した時のトリレンジイソシアネート（ＴＤＩ）とジエチレングリコール（ＤＥＧ）との反応速度定数Ｋ_１（Ｌ／ｍｏｌｅ×ｈｒ）と、ＴＤＩと水との反応速度定数Ｋ_２（Ｌ／ｍｏｌｅ×ｈｒ）の比であるＫ_２／Ｋ_１×ｌ０^−１（Ｒｅａｃｔｉｏｎ Ｒａｔｅ Ｃｏｎｓｔａｎｔ Ｒａｔｉｏ）が、ｌ０以上のものを示し〔例えば、Ｊｏｕｒｎａｌ ｏｆ Ｃｅｌｌｕｌａｒ Ｐｌａｓｔｉｃｓ，２３，４６１（１９８７）参照〕、例えば、ビス−２−ジメチルアミノエチルエーテル、Ｎ，Ｎ’，Ｎ”−トリメチルアミン、エチルエタノールアミン、ペンタメチルジエチレントリアミンなどを挙げることができる。
【００２０】
上記三級アミン系泡化触媒の使用量は、使用する有機ポリイソシアネートを基準にして２〜ｌ０重量％の範囲内で用いるのが適当である。尚、上記反応速度の比Ｋ_２／Ｋ_１×ｌ０^−１（Ｒｅａｃｔｉｏｎ Ｒａｔｅ ｃｏｎｓｔａｎｔ Ｒａｔｉｏ）が１０以下の触媒を主触媒として使用すると、発泡体密度の上昇、冬期の反応性低下や発泡体の二段発泡等の不都合を生じる場合がある。
【００２１】
又、本発明においては、反応速度調節のため、必要に応じて他のウレタン化触媒を上記泡化触媒の５０重量％以下、好ましくは４０重量％以下の範囲内で併用することができる。併用し得る他のウレタン化触媒としては、例えばトリエチレンジアミン、２−メチルトリエチレンジアミン、Ｎ，Ｎ−ジメチルアミノエチルモルフォリン、１−イソブチル−２−メチルイミダゾール、１，８−ジアザビシクロ（５，４，０）ウンデセン−７、１，５−ジアザビシクロ（４，３，０）ノネン−５等の三級アミン系触媒及びこれらの誘導体；カルボン酸等の酸との塩であるナフテン酸コバルト、テトラ（２−エチルヘキシル）チタネート、第二２−エチルヘキソエート鉄、コバルト−２−エチルヘキソエート、ナフテン酸亜鉛等の有機金属塩系触媒等を挙げることができる。
【００２２】
更に、本発明においては水を発泡補助剤として使用するが、使用量があまり多いと脆さや接着性等の物性が低下する傾向があるので、有機ポリイソシアネートを基準にして４重量％以下、特に２重量％以下の量で使用することが好ましい。
【００２３】
本発明においては、発泡体の難撚性を高めるため、必要に応じて三量化触媒を加えてイソシアヌレート化することもできる。使用できる三量化触媒としては例えば、Ｎ，Ｎ’，Ｎ”一トリス（ジメチルアミノプロピル）ヘキサヒドロ−Ｓ−トリアジン、２，４，６−トリスジメチルアミノメチルフェノール等の三級アミン系触媒；酢酸カリウム、オクタン酸カリウム、２−エチルヘキサン酸カリウム、炭酸ソーダ、しゅう酸鉄等の有機金属塩系触媒等を挙げることができる。
【００２４】
本発明においては更に、ポリウレタン発泡体の製造において使用されることのある他の添加剤、例えば、ジメチルシリコンのエチレンオキシド、プロピレンオキシド付加物、カチオン系界面活性剤、アニオン系界面活性剤、非イオン系界面活性剤などの整泡剤；トリス（２，３−ジブロモプロピル）フォスフェート、トリス−２一クロロエチルフォスフェート、トリメチルフォスフェート、トリエチルフォスフェート、トリブチルフォスフェートなどの難燃剤；ジブチルフォスフェート、ジオクチルフォスフェート、ポリプロピレンカーボネートなどの減粘剤；三酸化アンチモン、ゼオライト、ハジライトなどの充填剤；顔科、染科などの着色剤；等を適宜配合してもよい。
【００２５】
以上に述べた各種成分を用いてポリウレタン発泡体を製造する方法としては、例えば、有機ポリイソシアネート成分以外の成分をすべて混合してポリオール組成物を予め調製し、このポリオール組成物に有機ポリイソシアネート成分を添加混合し、型枠内に流し込むか又は基材表面に吹き付けた（例えばスプレー発泡機により）後、発泡硬化させる方法を例示することができる。発泡硬化に要する時間は、通常、５〜３０秒程度である
【００２６】
次に、実施例により本発明をさらに具体的に説明する。
【００２７】
【実施例】
実施例ｌ
ヒドロキシメチル基を有するベンジリックエーテル型フェノール樹脂（水酸基価＝５９６ｍｇＫＯＨ／ｇ）ｌ０ｇと、エチレンジアミン系ポリオール（水酸基価＝３ｌ５ｍｇＫＯＨ／ｇ、旭ガラス（株）製、ＸＲ ＦＤ−５０８０）２７．２５ｇと、有機錫系ウレタン化触媒（ジブチル錫ジアルキルマレート、勝田化工（株）製、Ｔ−５２ＮＪ）０．２５ｇと、三級アミン系泡化触媒（ビス−２一ジメチルアミノエチルエーテル、三共エアプロダクツ（株）製、ＤＡＢＣＯ ＢＬ−ｌ９）２．７５ｇと、整泡剤（シリコン系のもの）０．７５ｇと、難燃剤（トリエチルフォスフェート、大八化学（株）製、ＴＥＰ）８ｇと、水ｌｇの各成分を７５０ｍｌの容器中に秤量し、予備攪拌を行った後、粗ポリメチレンポリフェニルイソシアネート（クルードＭＤＩ）（日本ポリウレタン（株）製、ミリオネートＭＲ−２００）５０ｇを加え、室温でカゴ型攪拌機を用いて２０００ｒＰｍで１〜２秒間激しく攪拌し、そのままカップフリーで発泡硬化させた。得られた発泡体のクリームタイム及びライズタイム並びに密度（自由発泡密度）を下記表ｌ及び２に示す。
【００２８】
上記の組成に従い、ガスマ−発泡機により発泡体を得た。得られた発泡体のスプレ−発泡性、発泡状態、接着強度及び独立気泡率を以下の表１及び表２に示す。
【００２９】
尚、表１及び２におけるスプレ−発泡性、発泡状態、接着強度及び独立気泡率は、以下の基準により評価した。
スプレ−発泡性
スプレ−発泡の施工性につき以下のように評価し、結果を３段階で示した。
◎ 施工性良好（発泡体の横延び、二段発泡やダレがなく、仕上がり状態がよい）
○ 施工可能（発泡体の横延び、二段発泡やダレが多少あるが、見かけ上問題がない）
× 施工性不良（発泡体の横延び、二段発泡やダレがあり、施工できない）
発泡状態
発泡の状態につき以下のように評価し、結果を３段階で示した。
◎ 発泡状態良好（収縮及び割れなし）
○ 発泡状態に多少欠点あり（収縮等が一部みられる）
× 発泡状態不良（収縮及び割れがある）
接着強度
石膏ボ−ド上にスプレ−施工し、石膏ボ−ドとの接着強度につき引張り強度試験（ＪＩＳ−Ａ−９５２６）により評価し、結果を３段階で示した。
◎ 接着状態良好（接着強度が２Ｋｇｆ／ｃｍ^２以上）
○ 接着状態に多少欠点あり（剥がれ等が一部あり、接着強度が１〜２Ｋｇｆ／ｃｍ^２以上）
× 接着状態不良（接着強度が１Ｋｇｆ／ｃｍ^２以下）
独立気泡率
発泡後の発泡体の気泡の状態について評価し、結果を３段階で示した。この値が低いほど、熱伝導率が高くなり、断熱効果が劣る。
◎ 気泡の状態がほぼ独立気泡（独立気泡率が７０％以上）
○ 独立気泡が少ない（独立気泡率が４０〜７０％以上）
× 連続気泡が多い（独立気泡率が４０％以下）
【００３０】
実施例２乃至１８
表ｌに示す組成、配合割合で実施例１と同様の操作を行い、ポリウレタン発泡体を製造した。得られた発泡体のカップフリ−状態でのクリームタイム及びライズタイム、密度（自由発泡度）、スプレ−発泡性、発泡状態、接着強度及び独立気泡率を表ｌ及び２に示す。
【表１】

【表２】

【００３１】
比較例１乃至６
表３に示す組成、配合割合で実施例１と同様の操作を行い、ポリウレタン発泡体を製造した。得られた発泡体のカップフリ−状態でのクリームタイム及びライズタイム、密度（自由発泡度）、スプレ−発泡性、発泡状態、接着強度及び独立気泡率を表３に示す。但し、表３における◎、○及び×は、表１及び２における判断基準に従った。
【表３】

【００３２】
上記表１乃至３に明らかなように、本発明による発泡体は、比較例による発泡体よりも優れた物性を示し、特に接着強度において優れていた。
【００３３】
本発明の方法によれば、ベンジリックエーテル型フェノール樹脂、有機錫系ウレタン化触媒、三級アミン系泡化触媒、水等をコントロールすることにより、形成される発泡体の発泡倍率を自由に調節することができ、例えば、自由発泡密度が４０ｋｇ／ｍ^３以下、特に３０ｋｇ／ｍ^３以下という発泡倍率の大きい発泡体を製造することも可能である。
【００３４】
本発明の方法によって製造されるポリウレタン発泡体は、従来の水発泡による発泡体において問題となっていた接着性の低さ、脆さ等の物性を改艮することができる。又、例えばスプレー発泡に使用する際、液比（ＮＣＯ成分とＯＨ成分の比）を１：１に固定したまま従来の水発泡で発泡倍率を上げようとするとＯＨ成分中の水の比率を高くする必要が生じ、大量の水を使用しなければならず、その結果、その他のＯＨ成分には、ＯＨ価の大きい、即ち、分子量の高いポリオールを使用しなければならず、粘度を下げることを目的として難燃剤等の減粘剤を多量に添加する必要が生じ、そのため、フォームの強度が低下したり、接着性が低下するなどの欠点が生ずるが、本発明の方法によれば、減粘剤として難燃剤をｌ０％程度混合するだけで、容易にｌ００〜５００ｃｐの原液を調製し、発泡度の大きな発泡体を製造することができる。[0001]
[Industrial applications]
The present invention relates to a method for producing a polyurethane foam. More specifically, for example, there is no need to use a fluorine-containing halogenated hydrocarbon or other physical foaming agent, and foaming in place by a spray foaming machine or the like is possible. The present invention relates to a method for producing a polyurethane foam.
[0002]
[Prior art]
Conventionally, rigid polyurethane foam has been applied by spray foaming at construction sites for the purpose of preventing dew condensation and heat insulation of buildings, but the stock solution for polyurethane foam used in the conventional method includes foaming. As the agent, a fluorine-containing halogenated hydrocarbon is used in a proportion of about 15 to 40% by weight of the total stock solution. However, it is said that the use of the fluorine-containing halogenated hydrocarbon will be completely banned in the near future due to the problem of depletion of the ozone layer.
[0003]
[Problems to be solved by the invention]
Therefore, water and the like are being studied as a foaming agent in place of the fluorine-containing halogenated hydrocarbon. However, if an attempt is made to achieve a free foaming density equivalent to that of a conventional product (for example, 20 kg / m ³ ), the water is used together with a polyol component. Since about 40% of the entire isocyanate component to be used is used for urea bond generation, physical properties such as a decrease in adhesiveness of the foam and a manifestation of brittleness are caused.
[0004]
When water is used as the foam, two-stage foaming occurs due to the difference between the reaction rate between the isocyanate component and the polyol component and the reaction rate between the isocyanate component and water, and the foam is bonded. A gap between the surface of the object and the foam is apt to be formed. Naturally, in winter when the reaction between the isocyanate component and water does not proceed, a required low-density foam cannot be obtained. . Further, unfavorable problems arise in controlling foaming in spray foaming, such as an increase in the liquid ratio [the ratio of the NCO component to the OH component] and an increase in the stock solution viscosity.
[0005]
[Means for Solving the Problems]
An object of the present invention is to solve the above-mentioned drawbacks of the prior art and eliminate the need to use fluorine-containing hydrogen halide as a foaming agent, and furthermore, to use a spray foaming machine in summer and winter to form a polyurethane that can be foamed at a construction site. It is to provide a method for producing a foam.
[0006]
In order to achieve the above object, a configuration adopted by the present invention is a polyol component containing a benzylic ether type phenol resin having a hydroxymethyl group, and a benzylic ether having a hydroxymethyl group contained in the polyol component. A phenolic resin having a proportion of 20 to 100% by weight, based on the total amount of the polyol component, and an organic polyisocyanate component, an organotin-based urethanization catalyst and a tertiary amine-based foaming catalyst; The ratio K ₂ / K ₁ × of the reaction rate constant K ₁ of the reaction rate constant between tolylene diisocyanate and diethylene glycol and the reaction rate K ₂ of tolylene diisocyanate and water when the tertiary amine foaming catalyst is added. those values of l0 ^-1 is l0.0 above and in the presence of water, have a ratio of tertiary amine blowing catalysts It is characterized in that reacting a 2~l0 percent by weight based on the polyisocyanate.
[0007]
That is, as shown in the following reaction formula A, the inventors of the present invention convert a phenol (1) having a hydroxymethyl group at the o-position with an organic isocyanate (2) in the presence of an organotin-based urethanization catalyst. Reacts to generate carbon dioxide gas (see, for example, Hybrid Phenolic / Urethane Foams, Anthony J. PaPa and Frank E. Crickfield, Journalof Cellular Plastics, 258, September, and 19-79 to Septober). An attempt was made to use a phenolic resin having a hydroxymethyl group at the position as a polyol component for forming a polyurethane foam, and to use the generated carbon dioxide gas as a blowing agent for forming the foam.
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[0008]
However, a novolak phenol resin which is a phenol resin having a hydroxymethyl group at the o-position is generally difficult to use as a polyol component because it is solid and insoluble in a solvent. When used as a polyol, a large amount of water reacts with the isocyanate, making it difficult to control the reaction. Further, when the water content is reduced, the viscosity of the resin is increased, and the stirring efficiency is reduced. The inventors of the present invention have repeatedly conducted experiments focusing on a benzylic ether-type phenol resin having a water content of 0.5% or less and a viscosity of 1,000 to 20,000 cp. It has been found that it can be used as a polyol component.
[0009]
However, foaming was insufficient with only carbon dioxide gas generated from the reaction between the hydroxymethyl group of the benzylic ether type phenol resin and the organic isocyanate, and the desired low-density (high foaming degree) foam could not be obtained. . Therefore, the inventors of the present invention further studied, as a result, by adding water as a foaming aid, and further adding a tertiary amine-based foaming catalyst to promote the reaction between water and isocyanate, the above-mentioned In addition to the reaction represented by the reaction formula A, a carbon dioxide gas generation reaction accompanying the formation of a urea bond represented by the following reaction formula B can also be used, and it has been found that a desired low-density polyurethane foam can be produced. Is completed.
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[0010]
Hereinafter, the present invention will be described in detail.
[0011]
The present invention is characterized in that a benzylic ether-type phenol resin having a hydroxymethyl group is used as at least a part of a polyol component essential for producing a polyurethane foam, wherein the benzyl resin having a hydroxymethyl group is used. "Rick ether type phenolic resin" refers to a phenolic resin obtained by reacting a phenol with an aldehyde at a temperature of 100 to 130 ° C using a catalyst composed of, for example, a naphthenate of a divalent metal, a carboxylate, or the like. It is a kind of material whose properties can be changed from a viscous liquid to a semi-solid or solid depending on polymerization conditions. For example, it is produced according to the method described in JP-B-47-50873. Is what you can do.
[0012]
Such a benzylic ether-type phenol resin having a hydroxymethyl group (hereinafter, may be simply referred to as a benzylic ether-type phenol resin in this specification) is, for example, 300 to 700 mgKOH / g, preferably in terms of a hydroxyl value. Can be contained as a part of the polyol component in the range of 450 to 600 mgKOH / g.
[0013]
In the present invention, the benzylic ether type phenol resin can be used alone as the polyol component, but when used alone, the curing speed is too fast, and cracks and the like are easily generated inside the foam to be formed. In general, it is preferable to use the polyol in combination with another polyol. As other polyols that can be used in combination, those conventionally used in the production of polyurethane can be used in the present invention as well. For example, ethylene glycol, diethylene glycol, neopentyl glycol, 1,4-butanediol, dihydric alcohols such as 1,6-hexanediol and 1,4-cyclohexanedimethanol; trihydric or higher alcohols such as glycerin, trimethylolpropane, tris (2-hydroxyethyl) isocyanurate and pentaerythrol; The resulting polyester polyol, polyether polyol, ethylenediamine-based polyol, ether-based Mannich polyol, and the like can be given.
[0014]
The above-mentioned other polyols other than the benzylic ether type phenol resin can be used alone or in combination of two or more kinds, and ethylenediamine-based polyols and ether-based Mannich polyols are particularly preferable.
[0015]
When these other polyols are used in combination with the benzylic ether-type phenol resin, the amount of the benzylic ether-type phenol resin used is not strictly limited, and the physical properties desired for the foam to be formed are used in combination. Although it can be varied widely depending on the type of other polyols, it is convenient to use within the range of usually 20 to 100% by weight, particularly 30 to 80% by weight, based on the total amount of polyols.
[0016]
On the other hand, examples of the organic polyisocyanate component that reacts with the polyol component include aliphatic and alicyclic compounds containing two or more isocyanate groups (—NCO) in one molecule, which are conventionally used in the production of polyurethane. And aromatic and aromatic-aliphatic polyisocyanate compounds, such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate. A mixture of tolylene diisocyanate, crude tolylene diisocyanate, methylene diphenyl diisocyanate (MDI), aromatic polyisocyanate such as 4,4 ', 4 "-triphenylmethylene triisocyanate, polymethylene polyphenyl isocyanate (crude MDI); hexamethylene- 1,6-diisocyanate, water Examples thereof include aliphatic polyisocyanates such as added MDI, and among them, crude MDI is particularly preferable.
[0017]
The use ratio of the organic polyisocyanate component to the polyol component was 1 lNCO / OH equivalent. 0 to l. The range of 5 can be exemplified as a preferable example.
[0018]
In the present invention, an organotin-based urethanization catalyst is used to promote the reaction between the hydroxymethyl group of the benzylic ether type phenol resin and the isocyanate group of the organic polyisocyanate component. As the organotin-based urethanization catalyst, those generally used in a urethanization reaction can be used.For example, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dialkylmalate, tin stearate, tin octylate And the like. The amount of the organotin-based urethanization catalyst used is not particularly limited, but is usually 0.1% based on the total amount of the benzylic ether type phenol resin used. It is suitable to use in the range of 1 to 14% by weight, especially 0.4 to 9% by weight.
[0019]
In the present invention, a tertiary amine foaming catalyst is used in order to promote the water-isocyanate reaction. The foaming catalyst is defined as a reaction rate constant K ₁ (L / mole × hr) between tolylene diisocyanate (TDI) and diethylene glycol (DEG) when the catalyst is added, and a reaction rate constant K between TDI and water. K ₂ / K ₁ × 10 ⁻¹ (Reaction Rate Constant Ratio), which is a ratio of ₂ (L / mole × hr), indicates a value of 10 or more [see, for example, Journal of Cellular Plastics, 23, 461 (1987)]. ], For example, bis-2-dimethylaminoethyl ether, N, N ', N "-trimethylamine, ethylethanolamine, pentamethyldiethylenetriamine and the like.
[0020]
The use amount of the tertiary amine foaming catalyst is suitably in the range of 2 to 10% by weight based on the organic polyisocyanate used. When a catalyst having a reaction rate ratio K ₂ / K ₁ × 10 ^-1 (Reaction Rate constant Ratio) of 10 or less is used as a main catalyst, the foam density increases, the reactivity in winter decreases, and the foam Problems such as step foaming may occur.
[0021]
In the present invention, for the purpose of controlling the reaction rate, another urethane-forming catalyst can be used in combination within a range of 50% by weight or less, preferably 40% by weight or less of the foaming catalyst, if necessary. Other urethanization catalysts that may be used in combination include, for example, triethylenediamine, 2-methyltriethylenediamine, N, N-dimethylaminoethylmorpholine, 1-isobutyl-2-methylimidazole, 1,8-diazabicyclo (5,4, 0) tertiary amine catalysts such as undecene-7, 1,5-diazabicyclo (4,3,0) nonene-5 and derivatives thereof; cobalt naphthenate and tetra (2 -Ethylhexyl) titanate, ferric 2-ethylhexoate iron, cobalt-2-ethylhexoate, zinc naphthenate, and other organic metal salt catalysts.
[0022]
Further, in the present invention, water is used as a foaming aid, but if the amount is too large, physical properties such as brittleness and adhesiveness tend to decrease, so that 4% by weight or less based on the organic polyisocyanate, particularly It is preferred to use it in an amount of up to 2% by weight.
[0023]
In the present invention, in order to enhance the resistance to twisting of the foam, if necessary, a trimerization catalyst may be added for isocyanuration. Examples of the usable trimerization catalyst include tertiary amine catalysts such as N, N ', N "-tris (dimethylaminopropyl) hexahydro-S-triazine and 2,4,6-trisdimethylaminomethylphenol; potassium acetate And organic metal salt catalysts such as potassium octanoate, potassium 2-ethylhexanoate, sodium carbonate and iron oxalate.
[0024]
The present invention further provides other additives that may be used in the production of polyurethane foams, such as ethylene oxide and propylene oxide adducts of dimethyl silicon, cationic surfactants, anionic surfactants, nonionic surfactants. Foam stabilizers such as surfactants; flame retardants such as tris (2,3-dibromopropyl) phosphate, tris- 21-chloroethyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl phosphate; dibutyl phosphate; Thickeners such as dioctyl phosphate and polypropylene carbonate; fillers such as antimony trioxide, zeolite and hajilite; coloring agents such as facial and dyeing may be appropriately added.
[0025]
As a method for producing a polyurethane foam using the various components described above, for example, a polyol composition is prepared in advance by mixing all components other than the organic polyisocyanate component, and the organic polyisocyanate component is added to the polyol composition. Can be added and mixed, poured into a mold or sprayed on the surface of a substrate (for example, by a spray foaming machine), and then foam-hardened. The time required for foam hardening is usually about 5 to 30 seconds.
Next, the present invention will be described more specifically with reference to examples.
[0027]
【Example】
Example l
10 g of a benzylic ether type phenol resin having a hydroxymethyl group (hydroxyl value = 596 mg KOH / g) and 27.25 g of an ethylenediamine-based polyol (hydroxyl value = 315 mgKOH / g, XR FD-5080 manufactured by Asahi Glass Co., Ltd.) 0.25 g of an organotin-based urethanization catalyst (dibutyltin dialkyl malate, manufactured by Katsuta Kako Co., Ltd., T-52NJ) and a tertiary amine-based foaming catalyst (bis-21-dimethylaminoethyl ether, Sankyo Air Products ( 2.75 g of DABCO BL-19), 0.75 g of a foam stabilizer (silicone-based), 8 g of a flame retardant (triethyl phosphate, TEP manufactured by Daihachi Chemical Co., Ltd.), and 1 g of water After weighing each component in a 750 ml container and performing preliminary stirring, crude polymethylene polyphenyl isocyanate (C Over de MDI) (Nippon Polyurethane Co., Ltd., Millionate MR-200) 50 g was added and stirred for 1-2 seconds 2000rPm vigorously with a cage stirrer at room temperature to as foamed and cured in a cup-free. The cream time, rise time and density (free foam density) of the obtained foam are shown in Tables 1 and 2 below.
[0028]
According to the above composition, a foam was obtained by a gas foaming machine. Table 1 and Table 2 below show the spray-foamability, foaming state, adhesive strength and closed cell ratio of the obtained foam.
[0029]
The spray-foamability, foamed state, adhesive strength and closed cell rate in Tables 1 and 2 were evaluated according to the following criteria.
Spray-foamability The workability of spray-foam was evaluated as follows, and the results were shown in three stages.
◎ Good workability (no expansion of foam, no two-stage foaming or sagging, good finish)
○ Can be applied (the foam expands horizontally, there are some two-stage foaming and sagging, but there is no apparent problem)
× Poor workability (can not be applied due to lateral expansion of foam, two-stage foaming or sagging)
The state of foaming was evaluated as follows, and the results were shown in three stages.
◎ Good foaming state (no shrinkage and cracking)
○ Some defects in the foaming state (some shrinkage is seen)
× Bad foaming (shrinkage and cracking)
The adhesive strength was sprayed on the gypsum board, and the adhesive strength with the gypsum board was evaluated by a tensile strength test (JIS-A-9526), and the results were shown in three stages.
◎ Good adhesion state (adhesion strength is ² kgf / cm ² or more)
○ Some defects in the bonding state (partial peeling, etc., bonding strength is 1 to ² kgf / cm ² or more)
× Bad adhesion condition (adhesion strength is 1 kgf / cm ² or less)
The foam state of the foam after the closed cell rate foaming was evaluated, and the results were shown in three stages. The lower the value, the higher the thermal conductivity and the lower the heat insulating effect.
◎ Bubbles are almost closed cells (closed cell rate is 70% or more)
○ Less closed cells (closed cell rate is 40-70% or more)
× Many open cells (closed cell rate is 40% or less)
[0030]
Examples 2 to 18
The same operation as in Example 1 was performed using the composition and the mixing ratio shown in Table 1 to produce a polyurethane foam. Tables 1 and 2 show the cream time and rise time, density (free foaming degree), spray-foaming property, foaming state, adhesive strength and closed cell rate of the obtained foam in a cup-free state.
[Table 1]

[Table 2]

[0031]
Comparative Examples 1 to 6
The same operation as in Example 1 was performed using the composition and the mixing ratio shown in Table 3 to produce a polyurethane foam. Table 3 shows the cream time and rise time, density (free foaming degree), spray-foaming property, foaming state, adhesive strength and closed cell rate of the obtained foam in a cup-free state. However, ◎, 及 び, and × in Table 3 conformed to the criteria in Tables 1 and 2.
[Table 3]

[0032]
As is clear from Tables 1 to 3, the foam according to the present invention exhibited better physical properties than the foam according to the comparative example, and was particularly excellent in adhesive strength.
[0033]
According to the method of the present invention, by controlling the benzylic ether type phenol resin, the organotin-based urethanization catalyst, the tertiary amine-based foaming catalyst, water and the like, the expansion ratio of the foam to be formed can be freely adjusted. For example, it is also possible to produce a foam having a large expansion ratio, for example, a free foam density of 40 kg / m ³ or less, particularly 30 kg / m ³ or less.
[0034]
The polyurethane foam produced by the method of the present invention can improve physical properties such as low adhesiveness and brittleness, which have been problems in the conventional foam by water foaming. Also, for example, when using for spray foaming, if the ratio of water in the OH component is increased by the conventional water foaming while the liquid ratio (the ratio between the NCO component and the OH component) is fixed to 1: 1, the ratio of water in the OH component is increased. Therefore, a large amount of water must be used, and as a result, for other OH components, a polyol having a large OH value, that is, a polyol having a high molecular weight must be used, and it is necessary to reduce the viscosity. For the purpose, it is necessary to add a large amount of a viscosity reducing agent such as a flame retardant, so that there are disadvantages such as a decrease in the strength of the foam and a decrease in the adhesiveness. By simply mixing a flame retardant of about 10% as an agent, a stock solution of 100 to 500 cp can be easily prepared, and a foam having a high degree of foaming can be produced.

Claims (6)

A polyol component containing a benzylic ether type phenol resin having a hydroxymethyl group, the ratio of the benzylic ether type phenol resin having a hydroxymethyl group contained in the polyol component is based on the total amount of the polyol component. 20 to 100% by weight and an organic polyisocyanate component, an organotin-based urethanization catalyst and a tertiary amine-based foaming catalyst, which are added when the tertiary amine-based foaming catalyst is added. Water having a ratio K ₂ / K ₁ × 10 ^-1 of a reaction rate constant represented by a reaction rate constant K ₁ of diisocyanate and diethylene glycol and a reaction rate K ₂ of tolylene diisocyanate and water of not less than 10.0 and water under present in the 2~l0% by weight the proportion of tertiary amine blowing catalyst an organic polyisocyanate based Method for producing a polyurethane foam which comprises reacting Te. The method for producing a polyurethane foam according to claim 1, wherein the benzylic ether type phenol resin having a hydroxymethyl group contained in the polyol component has a hydroxyl value of 300 to 700 mgKOH / g. The ratio of the organic polyisocyanate component is 1 lNCO / OH equivalent based on the polyol component. 0 to l. The method for producing a polyurethane foam according to claim 1, which is 5. The ratio of the organotin-based urethanization catalyst is set to 0. The method for producing a polyurethane foam according to claim 1, wherein the content is 1 to 14% by weight. The method for producing a polyurethane foam according to claim 1, wherein the tertiary amine-based foaming catalyst further contains another urethane catalyst. The method for producing a polyurethane foam according to claim 1, wherein the proportion of water is 4% by weight or less based on the organic polyisocyanate.