JP4096446B2 - Transparent polyamide resin and method for producing the same - Google Patents

Description

（ここで、Ｒ₁はＣ_nＨ_2n（ｎ＝１〜３）の炭化水素、Ｒ₂およびＲ₃はＨあるいはＣ_nＨ_2n+1（ｎ＝１〜３）の炭化水素である。）
（（Ａ）のモル数）：（（Ｂ）のモル数）が１００：９５〜１００：１０５である透明ポリアミド樹脂。
【００１０】
又、本発明は、
（Ｃ）脂肪族アミノカルボン酸及び／又はラクタムから誘導される単位及び前記の（Ａ）、（Ｂ）からなるポリアミド樹脂であって、（Ａ）＋（Ｂ）の合計量１００モルに対して（Ｃ）が０モルより多く、３０モルより少ない割合で配合された透明ポリアミド樹脂である。
【００１１】
又、前記の透明ポリアミドを製造する際、前重合工程で数平均分子量が８００〜４，０００の範囲になるまで重合し、後重合工程で数平均分子量が７，０００〜３０，０００の範囲になるまで重合する前記の透明ポリアミド樹脂の製造法である。
【００１２】
【発明の実施の形態】
以下に、本発明を詳細に説明する。本発明のポリアミド樹脂を形成する（Ａ）のジカルボン酸は、（Ａ−１）１，６−デカンジカルボン酸と（Ａ−２）イソフタル酸で構成される。１，６−デカンジカルボン酸は、７−シアノウンデカン酸の加水分解、オレイン酸など不飽和カルボン酸のヒドロホルミル化、コッホ（Ｋｏｃｈ）−カルボキシル化、レッペ（Ｒｅｐｐｅ）−カルボキシル化などの公知の方法によって製造される。イソフタル酸は市販品をそのまま使用しても良いし、再結晶などにより精製してから使用しても良い。（Ａ）のジカルボン酸を構成する（Ａ−１）１，６−デカンジカルボン酸の割合は５０〜１００モル％、好ましくは６０〜９５モル％であり、（Ａ−２）イソフタル酸の割合は０〜５０モル％、好ましくは５〜４０モル％である。（Ａ−１）１，６−デカンジカルボン酸の割合が５０モル％未満の場合、得られるポリアミド樹脂のガラス転移温度が２００℃より高くなるため、重合時の溶融粘度が高くなり、均一な状態で溶融重合することが難しく、均質で、良好なポリアミド樹脂を得ることが出来なくなることがあり、好ましくない。
【００１３】
本発明のポリアミド樹脂を形成する（Ｂ）のジアミンは、構造式（１）で表される脂環族ジアミンである。
【化３】

（ここで、Ｒ₁はＣ_nＨ_2n（ｎ＝１〜３）の炭化水素、Ｒ₂およびＲ₃はＨあるいはＣ_nＨ_2n+1（ｎ＝１〜３）の炭化水素である。）
脂環式ジアミンの具体例としては、４，４’−ジアミノジシクロヘキシルメタン，４，４’−ジアミノ−３，３’−ジメチルジシクロヘキシルメタンおよび４，４’−ジアミノジシクロヘキシルプロパン等が挙げられる。これらは単独でも使用できるし、２種以上を適宜組合せて使用しても良い。
【００１４】
（Ａ）のジカルボン酸と（Ｂ）のジアミンの使用量は、モル比で（Ａ）：（Ｂ）が１００：９５〜１００：１０５、、好ましくは１００：９８〜１００：１０２である。（Ａ）のモル数は（Ａ−１）炭素数６〜２２の分岐型飽和ジカルボン酸のモル数と（Ａ−２）イソフタル酸のモル数の合計量である。
（Ａ）：（Ｂ）の比が過度にこの範囲を外れると製造されるポリアミドの数平均分子量の制御が難しくなり、目的のポリアミドを得ることが難しくなる。
【００１５】
（Ａ）と（Ｂ）とを重合させることにより得られるポリアミドは本発明目的の好ましいポリアミドである。又、（Ａ）、（Ｂ）及び（Ｃ）を重合させることにより得られるポリアミドも、本発明目的の好ましいポリアミドである。
本発明で使用される（Ｃ）の脂肪族アミノカルボン酸は炭素数４〜１２のω−アミノカルボン酸であり、又、ラクタムは炭素数４〜１２の環状アミド化合物（三員環以上のラクタム）である。脂肪族アミノカルボン酸の具体例としては、６−アミノカプロン酸、７−アミノヘプタン酸、８−アミノオクチル酸、９−アミノノナン酸、１０−アミノカプリン酸、１１−アミノウンデカン酸、１２−アミノドデカン酸などがある。ラクタムの具体例としては、ε−カプロラクタム、ω−エナントラクタム、ω−ウンデカンラクタム、ω−ドデカラクタムなどが挙げられる。このうち、本発明では１１−アミノウンデカン酸及び１２−アミノドデカン酸が好ましく、使用される。
【００１６】
本発明の脂肪族アミノカルボン酸及び／又はラクタムの使用量は（Ａ）と（Ｂ）の合計量１００モル％に対して０より多く、３０モル％より少ない量である。この量が３０モル％をこえる場合は、得られるポリアミド樹脂が結晶性となり易く、長時間の沸騰水処理により、透明性が失われたり、その成形品の形状が変化したりする。
【００１７】
本発明のポリアミドの製造法は上記原料が重合できる方法であれば、特に制約はない。通常、溶融重合法や溶液重合法が採用できるが、生産性の面から溶融重合法が好ましく採用される。重合反応の際、原料として上記（Ａ）及び（Ｂ）、又は、（Ａ）、（Ｂ）及び（Ｃ）をそのまま重合に使用しても良い。又、公知の方法であらかじめ、１，６−デカンジカルボン酸及び／又はイソフタル酸と脂環族ジアミンとのナイロン塩をつくり、これを原料として使用しても良い。
【００１８】
本発明のポリアミド樹脂の具体的な重合法の一例を以下に説明する。上記原料又は上記原料と水とを重合槽に仕込み、所定温度で加圧下又は常圧下に溶融重合を行う前重合工程とそれに引続いて前重合温度と同じか又はそれより高温で常圧下及び／又は減圧下に溶融重合を行う後重合工程により本発明の透明ポリアミド樹脂を製造することができる。
【００１９】
前重合工程は、原料をドライブレンドするか又は原料及び／又はナイロン塩を水溶液の形で混合するなどの方法により、所定の割合で原料を調整し、これに必要に応じて水を加えて重合槽に仕込み、撹拌下に温度１６０〜３２０℃、圧力０〜５０kgf/cm²Gの条件で５分〜１０時間重合させることにより実施される。
【００２０】
前重合工程での重合温度は１６０〜３２０℃、好ましくは１８０〜２８０℃、さらに好ましくは１８０〜２３０℃である。重合温度が１６０℃未満であると重合速度が遅くなり、重合時間が長くなりすぎるので好ましくない。又、重合温度が３２０℃より高くなると、得られるポリアミド樹脂の物性に好ましくない副反応や熱分解反応が起こり、ポリアミド樹脂が着色したり、ゲル化物が生成したり、物性が低下したりすることがあるので好ましくない。
【００２１】
前重合工程での圧力は重合槽内の圧力であり、主として重合槽に仕込んだ水と縮合反応によって生じた水とが示す水蒸気圧力である。従って、この圧力は温度及び水の使用量によって飽和水蒸気圧力以下の圧力に適宜調節できる。通常、この圧力は０〜５０kgf/cm²G、好ましくは０〜３０kgf/cm²Gである。
この圧力は、例えば、重合槽に直結された圧力調節弁などによって調節される。この圧力が０kgf/cm²G未満であると、原料中の蒸気圧の高いジアミンが重合槽外に蒸発してジカルボン酸とのモルバランスが崩れ、前重合物が所定の数平均分子量に到達しなくなることがある。又，圧力が５０kgf/cm²Gを越えると縮合反応が抑制され、前重合物が所定の数平均分子量に到達しなくなることがある。
【００２２】
前重合工程での重合時間は５分〜１０時間、好ましくは１０分〜７時間、さらに好ましくは３０分〜５時間である。重合時間が５分未満であると、重合が十分に進まず、前重合物が所定の数平均分子量に到達しなくなることがある。又、１０時間より長いと、長時間の加熱によって得られるポリアミド樹脂の物性が低下することがある。
【００２３】
本発明の原料に水を加えて前重合を行う場合、重合槽に水を仕込む方法は特に制約はない。原料及び／又はナイロン塩を水溶液として供給しても良く、又、所定量のイオン交換水などの純水または蒸留水などを別に供給しても良い。使用する水はイオン交換水などの純水または蒸留水を供給する直前に沸騰させて水中に溶存している酸素を取り除いた脱気水が好ましく使用される。水を使用する場合、重合槽に仕込む水の量は、通常、前記原料の合計量１００重量部当たり１〜１５０重量部である。
水の量が１重量部より少なくなると、前重合を溶融状態で安定して行うことが難しくなるため、好ましくない。また，水の量が１５０重量部より多くなると、前重合物が所定の数平均分子量に到達しなくなることがある。
【００２４】
本発明において、前重合物の数平均分子量は前重合物の末端基であるアミノ基濃度（以下「[ＮＨ2]」と記載することがある。）及びカルボキシル基濃度（以下「[ＣＯＯＨ]」と記載することがある。）から求められる数平均分子量（以下「Ｍｎ」と略記することがある。）が８００以上、好ましくは８００〜４，０００である。前重合物のＭｎが８００未満の場合、後重合工程でジアミンが系外へ留去し易くなり、末端基のアミノ基とカルボキシル基の濃度がアンバランスとなり、数平均分子量が上昇しないことがあるので好ましくない。数平均分子量が４，０００を越えると前重合時の溶融状態が不安定となることがあるので好ましくない。
【００２５】
本発明において、前重合を行う装置（前重合装置）は特に制約がなく、バッチ反応釜、又は１槽式ないし多槽式の連続反応装置、管状連続反応装置など公知のポリアミド樹脂の製造装置が使用できる。これらの中でも、前重合工程の重合時間が均一となるバッチ反応釜が好ましく用いられる。
【００２６】
以上の方法で得られた前重合物は、引続いて、後重合が行われる。後重合工程は溶融重合で行われ、重合温度は前重合と同じ温度又はそれより高温であり、圧力は常圧及び／又は減圧である。後重合工程での重合温度は１６０〜３２０℃、好ましくは２００〜３００℃、さらに好ましくは２３０〜２８０℃である。重合温度が１６０℃未満であると重合速度が遅くなり、重合時間が長くなるので好ましくない。又、重合温度が３２０℃より高い場合、ポリアミド樹脂の物性に好ましくない副反応や熱分解反応が起こってポリアミド樹脂が着色したり、ゲル化物が生成したり、得られたポリアミド樹脂の物性が低下したりするので好ましくない。
【００２７】
後重合工程での圧力は常圧及び／又は減圧であり、通常、１０〜７６０ｍｍＨｇ、好ましくは５０〜７６０ｍｍＨｇである。圧力が７６０ｍｍＨｇを越える加圧下では、前重合物中に含まれる水及び前重合物の縮合反応により生成する水からなる水蒸気を系外へ除去することが難しくなり、重縮合反応が十分進行しなくなることがあるので、好ましくない。又、圧力が１０ｍｍＨｇ未満では、重縮合反応の促進効果がそれ以上望めないだけてなく、排気のための減圧設備に多大のコストが必要となるので好ましくない。
【００２８】
減圧のための排気は、後重合工程に使用する装置に少なくとも１個のベント口を設け、該ベント口を大気解放状態にするか、又は、該ベント口をナッシュポンプ、メカニカルブースター、スチームエゼクターなどの公知の真空設備に接続して強制的に排気するなどの方法で行われる。
【００２９】
常圧下及び／又は減圧下における後重合の時間は数平均分子量が十分に大きくなり、かつ、重合物が熱分解しない条件で選ばれる。通常、１分〜１０時間である。重合時間が前記下限より短いと重合物の数平均分子量が十分に大きくならず、又、長くなると重合物が熱劣化を起こしたりするので、いずれの場合も所望の物性を有するポリアミド樹脂が得られなくなることがあるので好ましくない。
【００３０】
本発明のポリアミド樹脂を製造するプロセスは、特に制約はなく、バッチプロセスであっても、連続プロセスであってもよい。
バッチプロセスの場合、前記前重合工程と後重合工程を一つの反応装置で行っても良いし、又、前重合工程のみを加圧反応釜で行い、後重合工程は表面更新性に優れる１軸型混練押出機、２軸型混練押出機又は多軸型混練押出機などの混練押出機や特公平４-３２０９６号公報に開示された横型第２重合槽（２軸混合撹拌機）などの装置を用い、短時間で重合させても良い。
連続プロセスの場合、１槽式ないし多槽式の連続反応装置又は管状連続反応装置など公知の装置が使用できる。
【００３１】
後重合工程を経て得られる本発明の透明ポリアミド樹脂のＭｎは７，０００〜３０，０００の範囲にある。
Ｍｎが７，０００未満では所望の材料物性が得られなくなるので好ましくなく、３０，０００を越えると、得られたポリアミド樹脂の溶融粘度が高くなり溶融成形が困難となることがあるので好ましくない。
【００３２】
本発明の前重合工程又は後重合工程において、必要ならば重合促進剤や熱安定剤として無機系リン化合物などを添加しても良い。無機系リン化合物の具体例としては、リン酸、亜リン酸、次亜リン酸、ピロリン酸、ポリリン酸ならびにこれらのアルカリ金属塩やアルカリ土類金属塩などがある。
これら無機系リン化合物の使用量は，通常，得られるポリアミド樹脂に対して５０〜１０００ｐｐｍである。
添加方法は、特に制約がなく、例えば、前重合工程の際に原料モノマーとドライブレンドしたり、あるいは、前重合工程または後重合工程の際に水溶液として供給するなどの方法で行われる。
【００３３】
得られるポリアミド樹脂のＭｎや成形加工時の溶融粘度を安定化させるため、必要ならば、前重合工程又は後重合工程の際にアミンやカルボン酸などを分子量調節剤として添加することができる。添加するアミンやカルボン酸は一官能及び／又は二官能のものであれば特に制約はなく、具体例としては、ラウリルアミン、ステアリルアミン、ベンジルアミンなどのモノアミン、１，６-ジアミノヘキサン、１，７-ジアミノヘプタン、１，８-ジアミノオクタン、１，９-ジアミノノナン、１，１０-ジアミノデカン、１，１１-ジアミノウンデカン、１，１２-ジアミノドデカン、メタキシリレンジアミン、パラキシリレンジアミンなどのジアミン、酢酸、安息香酸、ラウリン酸、ステアリン酸などのモノカルボン酸及びブタンジオン酸、ペンタンジオン酸、ヘキサンジオン酸、オクタンジオン酸、ノナンジオン酸、デカンジオン酸、ウンデカンジオン酸、ドデカンジオン酸、イソフタル酸、テレフタル酸などのジカルボン酸が挙げられる。これらの分子量調節剤の使用量は、最終的に得ようとするポリアミド樹脂のＭｎが７，０００〜３０，０００の範囲になるように、適宜選択される。
【００３４】
さらに、本発明のポリアミド樹脂は前重合時あるいは後重合時に必要に応じ、耐熱剤、酸化防止剤、耐候剤、滑剤、帯電防止剤、顔料、染料、アンチブロッキング剤などをポリアミドの物性を損なわない範囲で添加することができる。
【００３５】
【実施例】
以下に実施例及び比較例を挙げて本発明をさらに詳しく説明する。ただし、本発明はこれらの実施例及び比較例によって何ら限定されるものではない。実施例及び比較例に示したポリアミド樹脂の諸物性は下記方法により測定した。
【００３６】
（１）相対粘度（ηr）の測定
ＪＩＳ Ｋ６８１０に準じ、９８重量％の濃硫酸を溶媒として、１重量／容量％のポリマー濃度で２５℃において、ウベローデ粘度計を用い、測定した。
【００３７】
（２）末端アミノ基濃度（[ＮＨ2]）の測定（単位はｅｑ／ｇ）
約１ｇのポリマーをフェノール／メタノール混合溶媒（容量比：９／１）４０ｍｌに溶解し、指示薬としてチモールブルーを用い、得られた試料溶液を１／２０規定の塩酸で滴定する方法で測定した。
【００３８】
（３）末端カルボキシル基濃度（[ＣＯＯＨ]）の測定（単位はｅｑ／ｇ）
約１ｇのポリマーに４０ｍｌのベンジルアルコールを加え、窒素ガス雰囲気下で加熱溶解し、指示薬としてフェノールフタレインを用い、得られた試料溶液を１／２０規定の水酸化カリウム−エタノール溶液で滴定する方法で測定した。
【００３９】
（４）数平均分子量（Ｍｎ）の求め方
前記（２）項記載の方法により求めた末端アミノ基濃度（[ＮＨ2]）と前記（３）項記載の方法により求めた末端カルボキシル基濃度（[ＣＯＯＨ]）の平均値の逆数として求めた。
【００４０】
（５）ガラス転移温度（Ｔｇ）の測定
試料ポリマーのガラス転移温度は１−ヘプタンとインジウムによって検定した（株）島津製作所製示差走査熱量計ＤＳＣ-５０を用い、試料ポリマーを液体窒素によって−５０℃まで冷却し、次に、１０℃/minの昇温速度で２００℃まで昇温して測定した。なお、測定中、試料ポリマーは３０ｍｌ/minの割合で供給されるヘリウムガスの雰囲気下に保った。Ｔｇの単位は℃である。
【００４１】
（６）沸騰水処理試験
加熱圧縮成形機（（株）神藤金属工業所製、Ｆ−３７型、型締力３７Ｔ）を使用し、２３０℃、１００kgf/cm²G、保持時間３分の条件で、試料のポリアミドを圧縮成形して、縦約２０ｍｍ、横約２０ｍｍ、厚さ約１ｍｍのシートをつくった。このシートを沸騰水（９５〜９９℃）中に浸漬し、１週間後のシートの透明性や変形の程度を目視で評価した。
【００４２】
実施例１
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた１ｌの圧力容器に、４，４’−ジアミノジシクロヘキシルメタン（以降「ＤＡＤＣＨＭ」と記載する。）１６８ｇ（０.７９８モル）と１，６−デカンジカルボン酸１８４ｇ（０.７９９モル）を仕込んだ。次いで、圧力容器内を十分窒素置換した後、撹拌下密閉状態で昇温し、圧力は１０kgf/cm²Gに保ちながら２００℃で３時間、前重合を行った。圧力を維持したままで、生成した前重合物を圧力容器底部の重合物取出口から数グラム抜き出した。得られたこのポリアミド樹脂は脆いガラス状ポリマーであった。３０〜４５℃で、４８時間以上真空乾燥した後、このポリアミド樹脂の[ＮＨ2]と[ＣＯＯＨ]を測定してＭｎを求めた。Ｍｎは２，８００であった。次いで、圧力容器内の温度を２８０℃まで３０分かけて昇温した。その時、圧力は２５kgf/cm²Gになった。温度を２８０℃に維持したままで、圧力容器内の圧力を３０分かけて徐々に放圧し、常圧にしてから、該容器内に２００ｍｌ/minの速度で窒素ガスを流しながら、２８０℃、７６０ｍｍＨｇで３時間、後重合を行った。その後、撹拌を止め、生成したポリアミド樹脂を圧力容器底部の重合物取出口からひも状に取り出し、水槽で冷却してから円柱状チップに切断した。このチップを８０℃で７２時間真空乾燥した。
得られたポリアミド樹脂は無色透明であり、このポリアミド樹脂を圧縮成形して得たシートを沸騰水中で１週間処理したが、透明なままであり、変形は観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外の変化は観察されず、アモルファス性であることが確認された。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４３】
実施例２
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器に４，４’−ジアミノ−３，３’−ジメチルジシクロヘキシルメタン（以降「ＤＡＭＤＣＨＭ」と記載する。）１７９ｇ（０.７５１モル）と１，６−デカンジカルボン酸１７３ｇ（０.７５１モル）を仕込んだ。
次に、圧力容器内を十分窒素置換した後、撹拌下密閉状態で昇温し、圧力を１２kgf/cm²Gに保ちながら２１０℃で４時間、前重合を行った。圧力を維持したままで、生成した前重合物を圧力容器底部の重合物取出口から数グラム抜き出した。得られたこのポリアミド樹脂は脆いガラス状ポリマーであった。３０〜４５℃で、４８時間以上真空乾燥した後、このポリアミド樹脂の[ＮＨ2]と[ＣＯＯＨ]を測定してＭｎを求めた。Ｍｎは２，５００であった。次いで、圧力容器内の温度を２８０℃まで３０分かけて昇温した。その時、圧力は２５kgf/cm²Gになった。温度を２８０℃に維持したままで、圧力容器内の圧力を３０分かけて、徐々に常圧まで放圧してから、該容器内に２００ｍｌ/minの速度で窒素ガスを流しながら、２８０℃、７６０ｍｍＨｇで４時間、後重合を行った。その後、撹拌を止め、生成したポリアミド樹脂を圧力容器底部の重合物取出口からひも状に取り出し、水槽で冷却してから円柱状チップに切断した。このチップを８０℃で７２時間真空乾燥した。得られたポリアミド樹脂は無色透明であり、このポリアミド樹脂を圧縮成形して得たシートを沸騰水中で１週間処理したが、透明なままであり、変形は観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されず、アモルファス性であることが確認された。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４４】
実施例３
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器に、４，４’−ジアミノジシクロヘキシルプロパン（以降、「ＤＡＤＣＨＰ」と記載する。）１８６ｇ（０.７８０モル）と１，６−デカンジカルボン酸１８０ｇ（０.７８１モル）を仕込んだ。次に、圧力容器内を十分窒素置換した後、撹拌下密閉状態で昇温し、圧力は１３kgf/cm²Gに保ちながら２２０℃で４時間、前重合を行った以外は、実施例２と同様の方法で実施した。前重合で得られたポリアミド樹脂のＭｎは２，１００であった。後重合で得られたポリアミド樹脂は、無色透明であり、このポリアミド樹脂を圧縮成形して得られたシートを沸騰水中で１週間処理したが、透明なままであり、変形も観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されなかった。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４５】
実施例４
撹拌機、温度計、圧力計、窒素導入口、放圧口および重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１６０ｇ（０.７６０モル）、１，６−デカンジカルボン酸１３１ｇ（０.５６９モル）、イソフタル酸３２ｇ（０.１９２モル）及び１２−アミノドデカン酸３６ｇ（０.１６７モル）を仕込んだ。次に，圧力容器内を十分窒素置換した後，撹拌下密閉状態で昇温し，圧力は１３kgf/cm2Gに保ちながら２００℃で４時間、前重合を行った以外は、実施例２と同様の方法で実施した。前重合で得たポリアミド樹脂のＭｎは３，０００であった。後重合で得られたポリアミド樹脂は、無色透明であり、このポリアミド樹脂を圧縮成形して得られたシートを沸騰水中で１週間処理したが、透明なままであり、変形も観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されなかった。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４６】
実施例５
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１５８ｇ（０.７５１モル）、１，６−デカンジカルボン酸１７３ｇ（０.７５１モル）、ω−ドデカラクタム４８ｇ（０.２４３モル）及びイオン交換水１８ｇを仕込んだ。
次に、圧力容器内を十分窒素置換した後、撹拌下密閉状態で昇温し、圧力を３０kgf/cm²Gに保ちながら２８０℃で５時間、前重合を行った以外は実施例２と同様の方法で実施した。前重合で得られたポリアミド樹脂のＭｎは３，３００であった。後重合で得られたポリアミド樹脂は、無色透明であり、このポリアミド樹脂を圧縮成形して得られたシートを沸騰水中で１週間処理したが、透明なままであり、変形も観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されなかった。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４７】
参考例１
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１４７ｇ（０.７０１モル）、８−エチルオクタデカンジオン酸２４０ｇ（０．７０１モル）及びイオン交換水１８ｇを仕込んだ。次に、圧力容器内を十分窒素置換した後、攪拌下密閉状態で昇温し、圧力を１７ｋｇｆ／ｃｍ²Ｇに保ちながら２３０℃で５時間、前重合を行った以外は、実施例２と同様の方法で実施した。前重合で得られたポリアミド樹脂のＭｎは３，８００であった。後重合で得られたポリアミド樹脂は、無色透明であり、このポリアミド樹脂を圧縮成形して得られたシートを沸騰水中で１週間処理したが、透明なままであり、変形も観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されなかった。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４８】
参考例２
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１２６ｇ（０.５９９モル）、８，１３−ジメチルエイコサジオン酸２２２ｇ（０．６００モル）及びイオン交換水２０ｇを仕込んだ。次に、圧力容器内を十分窒素置換した後、攪拌下密閉状態で昇温し、圧力を２０ｋｇｆ／ｃｍ²Ｇに保ちながら２３０℃で５時間、前重合を行った以外は、実施例２と同様の方法で実施した。前重合で得られたポリアミド樹脂のＭｎは３，６００であった。後重合で得られたポリアミド樹脂は、無色透明であり、このポリアミド樹脂を圧縮成形して得られたシートを沸騰水中で１週間処理したが、透明なままであり、変形も観察されなかった。このポリアミド樹脂の示差走査熱量分析ではＴｇ以外は観察されなかった。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００４９】
比較例１
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１３０ｇ（０.６１９モル）、１，６−デカンジカルボン酸５７ｇ（０.２４７モル）、イソフタル酸６２ｇ（０.３７３モル）及び１２−アミノドデカン酸１０９ｇ（０.５０６モル）を仕込んだ以外は、実施例４と同様の方法で実施した。
前重合で得られたポリアミド樹脂のＭｎは３，０００であった。後重合で得られたポリアミド樹脂は無色透明であったが、このポリアミド樹脂を圧縮成形して得たシートを沸騰水中で処理すると約１時間で透明性は失われた。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００５０】
比較例２
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１９０ｇ（０.９０３モル）、１，６−デカンジカルボン酸７５ｇ（０.３２６モル）、イソフタル酸９６ｇ（０.５７７モル）及びイオン交換水３６ｇを仕込んだ。
次に、圧力容器内を十分窒素置換した後、撹拌下密閉状態で昇温し、圧力を３０kgf/cm²Gに保ちながら２４０℃で４時間、前重合を行った。
前重合で得られたポリアミド樹脂のＭｎは１，１００であった。後重合後、生成したポリアミド樹脂を圧力容器底部の重合物取出口からひも状で取り出すために圧力容器内を２０kgf/cm²Gの窒素ガスで加圧したが、粘度が高く取り出すことができなかった。そのため、このポリアミド樹脂の沸騰水処理や示差走査熱量分析は実施しなかった。使用した原料名と仕込み組成を表１に示す。
【００５１】
比較例３
撹拌機、温度計、圧力計、窒素導入口、放圧口及び重合物取出口を備えた容量１ｌの圧力容器にＤＡＤＣＨＭ１１５ｇ（０.５４６モル）、１，６−デカンジカルボン酸１２５ｇ（０.５４４モル）及び１２−アミノドデカン酸１２０ｇ（０.５５７モル）を仕込んだ以外は実施例４と同様の方法で実施した。
前重合で得られたポリアミド樹脂のＭｎは３，０００であった。後重合で得られたポリアミド樹脂は無色透明であったが、このポリアミド樹脂を圧縮成形して得たシートを沸騰水中で処理すると約１時間で透明性は失われ、変形していた。使用した原料名と仕込み組成を表１に、得られたポリアミド樹脂の諸物性を表２にそれぞれ示す。
【００５２】
【表１】

【００５３】
【表２】

【００５４】
【発明の効果】
本発明は、特定の分岐型飽和ジカルボン酸と構造式（１）で表される脂環族ジアミンを必須成分とし、必要により脂肪族アミノカルボン酸及び／又はラクラムを構成成分とするポリアミド樹脂であって、該ポリアミド樹脂は、長時間の沸騰水処理後でも、透明性及びその成形品の形状はほとんど変化が見られない。
【化４】

（ここで、Ｒ₁はＣ_nＨ_2n（ｎ＝１〜３）の炭化水素、Ｒ₂およびＲ₃はＨあるいはＣ_nＨ_2n+1（ｎ＝１〜３）の炭化水素である。）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel transparent polyamide resin having units derived from a specific dicarboxylic acid and a diamine. More specifically, the present invention relates to a polyamide resin containing, as essential components, a branched saturated dicarboxylic acid having 6 to 22 carbon atoms and an alicyclic diamine having a specific molecular structure. The present invention relates to a polyamide resin that hardly changes in shape and a method for producing the same.
[0002]
[Prior art]
Polyamide resins are excellent in mechanical properties, heat resistance, oil resistance, gas barrier properties, and the like, and are used in various applications such as fibers, films, automobile parts, and electrical / electronic parts. Along with the expansion of application fields, there are demands for fibers, films, and covers for various devices that have characteristics of polyamide resin and have excellent transparency and shape retention of molded products.
[0003]
Conventionally, various proposals have been made regarding a method for obtaining a transparent and amorphous (amorphous) polyamide resin by suppressing the crystallinity of the polyamide resin. For example, a polyamide resin having an amide bond at the 1,3-position of cyclohexane or benzene is known as an amorphous polyamide resin that is transparent in appearance. For example, Japanese Patent Application Laid-Open No. 51-119794 discloses a copolyamide using 1,3-bisaminomethylcyclohexane, dodecanedioic acid or the like as a raw material. However, this polyamide resin loses its transparency or changes its shape due to boiling water treatment.
[0004]
It is known that a transparent and amorphous polyamide resin can be obtained by copolymerizing two or more monomer components. For example, a polyamide resin obtained by copolymerizing nylon 6, nylon 66 and / or nylon 12 which are aliphatic crystalline polyamide resins can be an amorphous copolyamide which is transparent in appearance at a specific composition ratio. Polym. Sci., Vol. 62, No. 13, 2237-2245 (1996). However, since this copolyamide is a combination of crystalline polyamide resins, crystallization progresses due to heat treatment, boiling water treatment, etc., and transparency is lost or the shape of the molded product changes. To do.
[0005]
Nylon 6T / 6I proposed in Japanese Patent Publication No. 49-36959 = 3/7 (copolyamide having a composition ratio of 3/7 using hexamethylenediamine and terephthalic acid, hexamethylenediamine and isophthalic acid as raw materials) is transparent It is said to have sex. However, this polyamide resin also loses transparency due to boiling water treatment, or the shape of the molded product changes.
[0006]
JP-A-5-310923 discloses nylon 6N / 6 (copolyamide using hexamethylenediamine, 2,6-naphthalenedicarboxylic acid and ε-caprolactam as raw materials), and JP-A-6-65371 discloses nylon. 6N / 6I (copolyamide using hexamethylenediamine and 2,6-naphthalenedicarboxylic acid, hexamethylenediamine and isophthalic acid as raw materials) has been introduced as a polyamide having transparency. However, it can be seen that any polyamide is crystalline from the endothermic peak of differential scanning calorimetry and the change in elastic modulus of dynamic solid viscoelasticity measurement. Therefore, by boiling water treatment, crystallization easily proceeds and transparency is lost.
[0007]
[Problems to be solved by the invention]
As described above, the known polyamide resin having transparency has a linear main chain skeleton composed of a carbon-carbon bond and an amide group, and is considered to have a stable structure by crystallization essentially. It is done. That is, most of the polyamide resins that are known to have transparency are transparent immediately after polymerization, even if they are transparent, when subjected to a boiling water treatment that promotes crystallization of the polyamide resin. Is lost or the shape of the molded product changes. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel polyamide resin having a high degree of transparency and a method for producing the same, in which the transparency and the shape of the molded product hardly change even after being subjected to a boiling water treatment for a long time.
[0008]
[Means for Solving the Problems]
  The present inventors have repeatedly investigated the relationship between transparency and the molecular structure of the polyamide resin in order to obtain a polyamide resin in which the transparency is not lost even after boiling water treatment for a long time and the shape of the molded product hardly changes. As a result,1,6-decanedicarboxylic acidAs a result, the present inventors have found that a polyamide having a specific alicyclic diamine as an essential component is excellent in transparency, and has reached the present invention.
[0009]
  That is, the present invention is a polyamide resin comprising (A) a unit derived from a dicarboxylic acid and (B) a unit derived from a diamine, wherein the dicarboxylic acid of (A) is (A-1)1,6-decanedicarboxylic acid50 to 100 mol% of units derived from (A-2) and 0 to 50 mol% of units derived from isophthalic acid, and the diamine of (B) is a diamine represented by structural formula (1),
[Chemical formula 2]

(Where R₁Is C_nH_2n(N = 1-3) hydrocarbon, R₂And R_ThreeIs H or C_nH_{2n + 1}(N = 1 to 3) hydrocarbon. )
(Number of moles of (A)): Transparent polyamide resin having (number of moles of (B)) of 100: 95 to 100: 105.
[0010]
The present invention also provides
(C) a polyamide resin comprising units derived from an aliphatic aminocarboxylic acid and / or lactam and the above (A) and (B), and the total amount of (A) + (B) is 100 mol (C) is a transparent polyamide resin blended in a proportion of more than 0 mol and less than 30 mol.
[0011]
Further, when the transparent polyamide is produced, it is polymerized until the number average molecular weight is in the range of 800 to 4,000 in the pre-polymerization step, and the number average molecular weight is in the range of 7,000 to 30,000 in the post-polymerization step. It is a manufacturing method of the said transparent polyamide resin polymerized until it becomes.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
  The present invention is described in detail below. The dicarboxylic acid (A) that forms the polyamide resin of the present invention is (A-1).1,6-decanedicarboxylic acidAnd (A-2) isophthalic acid.1,6-decanedicarboxylic acid is 7-It is produced by a known method such as hydrolysis of cyanoundecanoic acid, hydroformylation of unsaturated carboxylic acid such as oleic acid, Koch-carboxylation, Reppe-carboxylation. Isophthalic acid may be used as it is, or may be used after purification by recrystallization or the like. Constituting the dicarboxylic acid of (A) (A-1)1,6-decanedicarboxylic acidIs 50 to 100 mol%, preferably 60 to 95 mol%, and the proportion of (A-2) isophthalic acid is 0 to 50 mol%, preferably 5 to 40 mol%. (A-1)1,6-decanedicarboxylic acidWhen the ratio is less than 50 mol%, the resulting polyamide resin has a glass transition temperature higher than 200 ° C., so the melt viscosity at the time of polymerization is high, and it is difficult to perform melt polymerization in a uniform state, and is homogeneous and good. It may not be possible to obtain a new polyamide resin, which is not preferable.
[0013]
The diamine (B) that forms the polyamide resin of the present invention is an alicyclic diamine represented by the structural formula (1).
[Chemical Formula 3]

(Where R₁Is C_nH_2n(N = 1-3) hydrocarbon, R₂And R_ThreeIs H or C_nH_{2n + 1}(N = 1 to 3) hydrocarbon. )
Specific examples of the alicyclic diamine include 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4,4'-diaminodicyclohexylpropane, and the like. These may be used alone or in combination of two or more.
[0014]
The amount of the dicarboxylic acid (A) and the diamine (B) used is such that (A) :( B) is 100: 95 to 100: 105, preferably 100: 98 to 100: 102, as a molar ratio. The number of moles of (A) is the total amount of (A-1) the number of moles of branched saturated dicarboxylic acid having 6 to 22 carbon atoms and the number of moles of (A-2) isophthalic acid.
When the ratio of (A) :( B) is excessively out of this range, it becomes difficult to control the number average molecular weight of the produced polyamide, and it becomes difficult to obtain the target polyamide.
[0015]
Polyamides obtained by polymerizing (A) and (B) are preferred polyamides for the purposes of the present invention. Polyamides obtained by polymerizing (A), (B) and (C) are also preferred polyamides for the purposes of the present invention.
The aliphatic aminocarboxylic acid (C) used in the present invention is a ω-aminocarboxylic acid having 4 to 12 carbon atoms, and the lactam is a cyclic amide compound having 4 to 12 carbon atoms (a lactam having three or more members). ). Specific examples of the aliphatic aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctylic acid, 9-aminononanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and so on. Specific examples of the lactam include ε-caprolactam, ω-enantolactam, ω-undecanactam, and ω-dodecalactam. Of these, 11-aminoundecanoic acid and 12-aminododecanoic acid are preferred and used in the present invention.
[0016]
The amount of the aliphatic aminocarboxylic acid and / or lactam used in the present invention is more than 0 and less than 30 mol% with respect to 100 mol% of the total amount of (A) and (B). When this amount exceeds 30 mol%, the obtained polyamide resin tends to be crystalline, and transparency is lost or the shape of the molded product changes due to the boiling water treatment for a long time.
[0017]
  The method for producing the polyamide of the present invention is not particularly limited as long as the raw material can be polymerized. Usually, a melt polymerization method or a solution polymerization method can be employed, but the melt polymerization method is preferably employed from the viewpoint of productivity. In the polymerization reaction, the above (A) and (B) or (A), (B) and (C) may be used for polymerization as they are as raw materials. In addition, in a known method,1,6-decanedicarboxylic acidIn addition, a nylon salt of isophthalic acid and alicyclic diamine may be prepared and used as a raw material.
[0018]
An example of a specific polymerization method for the polyamide resin of the present invention will be described below. The above-mentioned raw material or the above-mentioned raw material and water are charged into a polymerization tank, and a pre-polymerization step in which melt polymerization is performed at a predetermined temperature under pressure or normal pressure, followed by normal pressure at the same or higher temperature than the pre-polymerization temperature and / or Alternatively, the transparent polyamide resin of the present invention can be produced by a post-polymerization step in which melt polymerization is performed under reduced pressure.
[0019]
In the pre-polymerization step, the raw materials are prepared at a predetermined ratio by dry blending the raw materials or mixing the raw materials and / or nylon salt in the form of an aqueous solution, and water is added to this as necessary to perform polymerization. Prepared in a tank, with stirring, temperature 160-320 ° C, pressure 0-50kgf / cm²It is carried out by polymerizing under the conditions of G for 5 minutes to 10 hours.
[0020]
The polymerization temperature in the prepolymerization step is 160 to 320 ° C, preferably 180 to 280 ° C, more preferably 180 to 230 ° C. When the polymerization temperature is lower than 160 ° C., the polymerization rate is slow, and the polymerization time becomes too long, which is not preferable. Moreover, when the polymerization temperature is higher than 320 ° C., undesirable side reactions and thermal decomposition reactions occur in the properties of the obtained polyamide resin, and the polyamide resin may be colored, a gelled product may be formed, or the properties may be deteriorated. This is not preferable.
[0021]
The pressure in the prepolymerization step is a pressure in the polymerization tank, and is a water vapor pressure mainly indicated by water charged in the polymerization tank and water generated by the condensation reaction. Therefore, this pressure can be appropriately adjusted to a pressure equal to or lower than the saturated water vapor pressure depending on the temperature and the amount of water used. Usually this pressure is 0-50kgf / cm²G, preferably 0-30kgf / cm²G.
This pressure is adjusted by, for example, a pressure control valve directly connected to the polymerization tank. This pressure is 0kgf / cm²If it is less than G, the diamine having a high vapor pressure in the raw material evaporates out of the polymerization tank, the molar balance with the dicarboxylic acid is lost, and the prepolymer may not reach the predetermined number average molecular weight. The pressure is 50kgf / cm²When it exceeds G, the condensation reaction is suppressed, and the prepolymer may not reach a predetermined number average molecular weight.
[0022]
The polymerization time in the prepolymerization step is 5 minutes to 10 hours, preferably 10 minutes to 7 hours, and more preferably 30 minutes to 5 hours. If the polymerization time is less than 5 minutes, the polymerization may not proceed sufficiently, and the prepolymer may not reach the predetermined number average molecular weight. If it is longer than 10 hours, the physical properties of the polyamide resin obtained by heating for a long time may be lowered.
[0023]
When water is added to the raw material of the present invention for prepolymerization, there is no particular limitation on the method for charging water into the polymerization tank. The raw material and / or nylon salt may be supplied as an aqueous solution, or a predetermined amount of pure water such as ion exchange water or distilled water may be supplied separately. The water to be used is preferably deaerated water which is boiled immediately before supplying pure water such as ion exchange water or distilled water to remove oxygen dissolved in the water. When water is used, the amount of water charged into the polymerization tank is usually 1 to 150 parts by weight per 100 parts by weight of the total amount of the raw materials.
When the amount of water is less than 1 part by weight, it is difficult to perform prepolymerization stably in a molten state, which is not preferable. On the other hand, if the amount of water exceeds 150 parts by weight, the prepolymer may not reach a predetermined number average molecular weight.
[0024]
In the present invention, the number average molecular weight of the prepolymer is described as the amino group concentration (hereinafter sometimes referred to as “[NH2]”) and the carboxyl group concentration (hereinafter referred to as “[COOH]”) as terminal groups of the prepolymer. The number average molecular weight (hereinafter sometimes abbreviated as “Mn”) obtained from the above is 800 or more, preferably 800 to 4,000. When Mn of the prepolymer is less than 800, the diamine is easily distilled out of the system in the postpolymerization step, the concentration of the amino group and carboxyl group of the terminal group becomes unbalanced, and the number average molecular weight may not increase. Therefore, it is not preferable. If the number average molecular weight exceeds 4,000, the molten state at the time of prepolymerization may become unstable, which is not preferable.
[0025]
In the present invention, the prepolymerization apparatus (prepolymerization apparatus) is not particularly limited, and a known polyamide resin production apparatus such as a batch reaction kettle, a one-tank or multi-tank continuous reaction apparatus, or a tubular continuous reaction apparatus may be used. Can be used. Among these, a batch reaction kettle in which the polymerization time in the prepolymerization step is uniform is preferably used.
[0026]
The prepolymer obtained by the above method is subsequently subjected to postpolymerization. The post-polymerization step is performed by melt polymerization, the polymerization temperature is the same as or higher than the pre-polymerization, and the pressure is normal pressure and / or reduced pressure. The polymerization temperature in the post-polymerization step is 160 to 320 ° C, preferably 200 to 300 ° C, more preferably 230 to 280 ° C. A polymerization temperature of less than 160 ° C. is not preferable because the polymerization rate becomes slow and the polymerization time becomes long. In addition, when the polymerization temperature is higher than 320 ° C., undesirable side reactions or thermal decomposition reactions occur in the properties of the polyamide resin, the polyamide resin is colored, a gelled product is formed, or the properties of the obtained polyamide resin are deteriorated. This is not preferable.
[0027]
The pressure in the post-polymerization step is normal pressure and / or reduced pressure, and is usually 10 to 760 mmHg, preferably 50 to 760 mmHg. When the pressure exceeds 760 mmHg, it becomes difficult to remove water contained in the prepolymer and water vapor formed by the condensation reaction of the prepolymer out of the system, and the polycondensation reaction does not proceed sufficiently. This is not preferable. Moreover, if the pressure is less than 10 mmHg, the effect of promoting the polycondensation reaction cannot be expected any more, and the decompression equipment for exhausting requires a large amount of cost, which is not preferable.
[0028]
For exhaust for decompression, at least one vent port is provided in a device used in the post-polymerization process, and the vent port is opened to the atmosphere, or the vent port is a Nash pump, mechanical booster, steam ejector, etc. It is performed by a method such as forcibly evacuating by connecting to a known vacuum equipment.
[0029]
The time for post-polymerization under normal pressure and / or reduced pressure is selected under the condition that the number average molecular weight is sufficiently large and the polymer is not thermally decomposed. Usually 1 minute to 10 hours. If the polymerization time is shorter than the lower limit, the number average molecular weight of the polymer will not be sufficiently large, and if it is longer, the polymer will be thermally deteriorated, and in any case, a polyamide resin having desired physical properties will not be obtained. This is not preferable.
[0030]
The process for producing the polyamide resin of the present invention is not particularly limited, and may be a batch process or a continuous process.
In the case of a batch process, the pre-polymerization step and the post-polymerization step may be performed in a single reaction apparatus, or only the pre-polymerization step is performed in a pressure reactor, and the post-polymerization step is a single shaft with excellent surface renewability. Equipment such as a kneading extruder such as a mold kneading extruder, a biaxial kneading extruder or a multi-shaft kneading extruder, or a horizontal second polymerization tank (biaxial mixing agitator) disclosed in Japanese Examined Patent Publication No. 4-32096 And may be polymerized in a short time.
In the case of a continuous process, a known apparatus such as a one-tank or multi-tank continuous reaction apparatus or a tubular continuous reaction apparatus can be used.
[0031]
Mn of the transparent polyamide resin of this invention obtained through a post-polymerization process exists in the range of 7,000-30,000.
If Mn is less than 7,000, the desired material properties cannot be obtained. This is not preferable, and if it exceeds 30,000, the resulting polyamide resin has a high melt viscosity, which may make melt molding difficult.
[0032]
In the prepolymerization step or postpolymerization step of the present invention, if necessary, an inorganic phosphorus compound or the like may be added as a polymerization accelerator or a heat stabilizer. Specific examples of the inorganic phosphorus compound include phosphoric acid, phosphorous acid, hypophosphorous acid, pyrophosphoric acid, polyphosphoric acid, and alkali metal salts and alkaline earth metal salts thereof.
The amount of these inorganic phosphorus compounds used is usually 50 to 1000 ppm with respect to the obtained polyamide resin.
The addition method is not particularly limited. For example, the addition method is dry blended with the raw material monomer in the prepolymerization step, or is supplied as an aqueous solution in the prepolymerization step or the postpolymerization step.
[0033]
In order to stabilize the Mn of the obtained polyamide resin and the melt viscosity at the time of molding, if necessary, amine, carboxylic acid or the like can be added as a molecular weight regulator in the prepolymerization step or the postpolymerization step. The amine or carboxylic acid to be added is not particularly limited as long as it is monofunctional and / or bifunctional. Specific examples thereof include monoamines such as laurylamine, stearylamine and benzylamine, 1,6-diaminohexane, 1, 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, metaxylylenediamine, paraxylylenediamine, etc. Monocarboxylic acids such as diamine, acetic acid, benzoic acid, lauric acid, stearic acid, butanedioic acid, pentadandioic acid, hexanedioic acid, octanedioic acid, nonandionic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, isophthalic acid, And dicarboxylic acids such as terephthalic acid. The amount of these molecular weight regulators to be used is appropriately selected so that the final Mn of the polyamide resin to be obtained is in the range of 7,000 to 30,000.
[0034]
Furthermore, the polyamide resin of the present invention does not impair the physical properties of the polyamide, such as heat-resistant agent, antioxidant, weathering agent, lubricant, antistatic agent, pigment, dye, anti-blocking agent, etc. It can be added in a range.
[0035]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited by these examples and comparative examples. Various physical properties of the polyamide resins shown in Examples and Comparative Examples were measured by the following methods.
[0036]
(1) Measurement of relative viscosity (ηr)
According to JIS K6810, the measurement was carried out using an Ubbelohde viscometer at a polymer concentration of 1% by weight / volume at 25 ° C. using 98% by weight concentrated sulfuric acid as a solvent.
[0037]
(2) Measurement of terminal amino group concentration ([NH2]) (unit: eq / g)
About 1 g of the polymer was dissolved in 40 ml of a phenol / methanol mixed solvent (volume ratio: 9/1), thymol blue was used as an indicator, and the obtained sample solution was titrated with 1/20 normal hydrochloric acid.
[0038]
(3) Measurement of terminal carboxyl group concentration ([COOH]) (unit: eq / g)
A method in which 40 ml of benzyl alcohol is added to about 1 g of polymer, heated and dissolved in a nitrogen gas atmosphere, phenolphthalein is used as an indicator, and the obtained sample solution is titrated with a 1/20 normal potassium hydroxide-ethanol solution. Measured with
[0039]
(4) How to find the number average molecular weight (Mn)
The terminal amino group concentration ([NH2]) determined by the method described in (2) above and the terminal carboxyl group concentration ([COOH]) determined by the method described in (3) were calculated as the reciprocal of the average value.
[0040]
(5) Measurement of glass transition temperature (Tg)
The glass transition temperature of the sample polymer was determined by 1-heptane and indium. A differential scanning calorimeter DSC-50 manufactured by Shimadzu Corporation was used to cool the sample polymer to −50 ° C. with liquid nitrogen, and then 10 ° C. / The temperature was raised to 200 ° C. at a rate of min rise and measured. During the measurement, the sample polymer was kept in an atmosphere of helium gas supplied at a rate of 30 ml / min. The unit of Tg is ° C.
[0041]
(6) Boiling water treatment test
Using a heat compression molding machine (Shinto Metal Industries Co., Ltd., F-37 type, clamping force 37T), 230 ° C., 100 kgf / cm²The sample polyamide was compression molded under the conditions of G and holding time of 3 minutes to produce a sheet having a length of about 20 mm, a width of about 20 mm and a thickness of about 1 mm. This sheet was immersed in boiling water (95 to 99 ° C.), and the transparency and the degree of deformation of the sheet after one week were visually evaluated.
[0042]
Example 1
168 g of 4,4′-diaminodicyclohexylmethane (hereinafter referred to as “DADCHM”) in a 1 l pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet. 0.798 mol) and 184 g (0.799 mol) of 1,6-decanedicarboxylic acid were charged. Next, after the inside of the pressure vessel is sufficiently purged with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is 10 kgf / cm.²While maintaining G, prepolymerization was performed at 200 ° C. for 3 hours. While maintaining the pressure, several grams of the produced prepolymer was withdrawn from the polymer outlet at the bottom of the pressure vessel. The obtained polyamide resin was a brittle glassy polymer. After vacuum drying at 30 to 45 ° C. for 48 hours or longer, [NH2] and [COOH] of this polyamide resin were measured to obtain Mn. Mn was 2,800. Next, the temperature in the pressure vessel was raised to 280 ° C. over 30 minutes. At that time, the pressure is 25kgf / cm²I became G. While maintaining the temperature at 280 ° C., the pressure in the pressure vessel is gradually released over 30 minutes to normal pressure, and then at 280 ° C. while flowing nitrogen gas through the vessel at a rate of 200 ml / min. Post-polymerization was performed at 760 mmHg for 3 hours. Thereafter, stirring was stopped, and the produced polyamide resin was taken out in a string form from the polymer outlet at the bottom of the pressure vessel, cooled in a water tank, and then cut into cylindrical chips. This chip was vacuum-dried at 80 ° C. for 72 hours.
The obtained polyamide resin was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. In the differential scanning calorimetry of this polyamide resin, no changes other than Tg were observed, and it was confirmed to be amorphous. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0043]
Example 2
4,4′-diamino-3,3′-dimethyldicyclohexylmethane (hereinafter “DAMDCHM”) was added to a 1 liter pressure vessel equipped with a stirrer, thermometer, pressure gauge, nitrogen inlet, pressure outlet and polymer outlet. 179 g (0.751 mol) and 173 g (0.751 mol) of 1,6-decanedicarboxylic acid were charged.
Next, after the inside of the pressure vessel is sufficiently substituted with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is set to 12 kgf / cm.²While maintaining G, prepolymerization was performed at 210 ° C. for 4 hours. While maintaining the pressure, several grams of the produced prepolymer was withdrawn from the polymer outlet at the bottom of the pressure vessel. The obtained polyamide resin was a brittle glassy polymer. After vacuum drying at 30 to 45 ° C. for 48 hours or longer, [NH2] and [COOH] of this polyamide resin were measured to obtain Mn. Mn was 2,500. Next, the temperature in the pressure vessel was raised to 280 ° C. over 30 minutes. At that time, the pressure is 25kgf / cm²I became G. While maintaining the temperature at 280 ° C., the pressure in the pressure vessel was gradually released to normal pressure over 30 minutes, and then at 280 ° C. while flowing nitrogen gas at a rate of 200 ml / min into the vessel. Post-polymerization was performed at 760 mmHg for 4 hours. Thereafter, stirring was stopped, and the produced polyamide resin was taken out in a string form from the polymer outlet at the bottom of the pressure vessel, cooled in a water tank, and then cut into cylindrical chips. This chip was vacuum-dried at 80 ° C. for 72 hours. The obtained polyamide resin was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. In the differential scanning calorimetry of this polyamide resin, nothing other than Tg was observed, and it was confirmed to be amorphous. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0044]
Example 3
4,4′-Diaminodicyclohexylpropane (hereinafter referred to as “DADCHP”) is placed in a 1-liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet. 186 g (0.780 mol) and 1,6-decanedicarboxylic acid 180 g (0.781 mol) were charged. Next, after sufficiently replacing the inside of the pressure vessel with nitrogen, the temperature was raised in a sealed state with stirring, and the pressure was 13 kgf / cm.²The same procedure as in Example 2 was performed except that prepolymerization was performed at 220 ° C. for 4 hours while maintaining G. Mn of the polyamide resin obtained by prepolymerization was 2,100. The polyamide resin obtained by the post-polymerization was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. No differential scanning calorimetric analysis of this polyamide resin was observed except for Tg. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0045]
Example 4
In a 1 liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet, DADCHM 160 g (0.760 mol), 1,6-decanedicarboxylic acid 131 g (0.569) Mol), 32 g (0.192 mol) of isophthalic acid and 36 g (0.167 mol) of 12-aminododecanoic acid were charged. Next, after the inside of the pressure vessel was sufficiently purged with nitrogen, the temperature was raised in a sealed state with stirring, and the same polymerization as in Example 2 was conducted except that prepolymerization was performed at 200 ° C. for 4 hours while maintaining the pressure at 13 kgf / cm 2 G. The method was carried out. Mn of the polyamide resin obtained by prepolymerization was 3,000. The polyamide resin obtained by the post-polymerization was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. No differential scanning calorimetric analysis of this polyamide resin was observed except for Tg. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0046]
Example 5
In a 1 liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet and a polymer outlet, 158 g of DADCHM (0.751 mol), 173 g of 1,6-decanedicarboxylic acid (0.751) Mol), 48 g (0.243 mol) of ω-dodecalactam and 18 g of ion-exchanged water were charged.
Next, after the inside of the pressure vessel is sufficiently purged with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is increased to 30 kgf / cm.²The same procedure as in Example 2 was performed except that prepolymerization was performed at 280 ° C. for 5 hours while maintaining G. Mn of the polyamide resin obtained by prepolymerization was 3,300. The polyamide resin obtained by the post-polymerization was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. No differential scanning calorimetric analysis of this polyamide resin was observed except for Tg. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0047]
Reference example 1
  In a pressure vessel having a capacity of 1 liter equipped with a stirrer, thermometer, pressure gauge, nitrogen inlet, pressure relief port and polymer outlet, DADCHM 147 g (0.701 mol), 8-ethyloctadecandioic acid 240 g (0.701 mol) ) And 18 g of ion-exchanged water were charged. Next, after the inside of the pressure vessel is sufficiently purged with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is increased to 17 kgf / cm.²The same procedure as in Example 2 was performed except that prepolymerization was performed at 230 ° C. for 5 hours while maintaining G. Mn of the polyamide resin obtained by prepolymerization was 3,800. The polyamide resin obtained by the post-polymerization was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. No differential scanning calorimetric analysis of this polyamide resin was observed except for Tg. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0048]
Reference example 2
  In a 1 liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet, 126 g (0.599 mol) of DADCHM, 222 g of 8,13-dimethyleicosadioic acid (0 .600 mol) and 20 g of ion-exchanged water were charged. Next, after the inside of the pressure vessel is sufficiently purged with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is increased to 20 kgf / cm.²The same procedure as in Example 2 was performed except that prepolymerization was performed at 230 ° C. for 5 hours while maintaining G. Mn of the polyamide resin obtained by prepolymerization was 3,600. The polyamide resin obtained by the post-polymerization was colorless and transparent, and a sheet obtained by compression molding this polyamide resin was treated in boiling water for 1 week, but remained transparent and no deformation was observed. No differential scanning calorimetric analysis of this polyamide resin was observed except for Tg. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0049]
Comparative Example 1
In a 1 liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet, 130 g (0.619 mol) DADCHM and 57 g (0.247) 1,6-decanedicarboxylic acid were added. Mol), 62 g (0.373 mol) of isophthalic acid, and 109 g (0.506 mol) of 12-aminododecanoic acid were used in the same manner as in Example 4.
Mn of the polyamide resin obtained by prepolymerization was 3,000. The polyamide resin obtained by post-polymerization was colorless and transparent. However, when a sheet obtained by compression molding this polyamide resin was treated in boiling water, the transparency was lost in about 1 hour. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0050]
Comparative Example 2
In a 1 liter pressure vessel equipped with a stirrer, a thermometer, a pressure gauge, a nitrogen inlet, a pressure outlet, and a polymer outlet, 190 g (0.903 mol) DADCHM and 75 g (0.326) 1,6-decanedicarboxylic acid were added. Mol), 96 g (0.577 mol) of isophthalic acid and 36 g of ion-exchanged water were charged.
Next, after the inside of the pressure vessel is sufficiently purged with nitrogen, the temperature is raised in a sealed state with stirring, and the pressure is increased to 30 kgf / cm.²While maintaining G, prepolymerization was carried out at 240 ° C. for 4 hours.
Mn of the polyamide resin obtained by prepolymerization was 1,100. After post-polymerization, the inside of the pressure vessel is 20 kgf / cm in order to take out the produced polyamide resin in a string form from the polymer outlet at the bottom of the pressure vessel.²Although pressurized with nitrogen gas of G, the viscosity was high and could not be taken out. Therefore, neither boiling water treatment nor differential scanning calorimetry analysis of this polyamide resin was performed. Table 1 shows the names of raw materials used and preparation compositions.
[0051]
Comparative Example 3
In a 1 liter pressure vessel equipped with a stirrer, thermometer, pressure gauge, nitrogen inlet, pressure outlet and polymer outlet, DADCHM 115 g (0.546 mol), 1,6-decanedicarboxylic acid 125 g (0.544). Mol) and 120 g (0.557 mol) of 12-aminododecanoic acid were used in the same manner as in Example 4.
Mn of the polyamide resin obtained by prepolymerization was 3,000. The polyamide resin obtained by post-polymerization was colorless and transparent. However, when a sheet obtained by compression-molding this polyamide resin was treated in boiling water, the transparency was lost and deformed in about 1 hour. Table 1 shows the names of raw materials and preparation compositions used, and Table 2 shows various physical properties of the obtained polyamide resin.
[0052]
[Table 1]

[0053]
[Table 2]

[0054]
【The invention's effect】
The present invention is a polyamide resin comprising a specific branched saturated dicarboxylic acid and an alicyclic diamine represented by the structural formula (1) as essential components and, if necessary, an aliphatic aminocarboxylic acid and / or lactam as constituent components. Thus, the transparency and the shape of the molded product of the polyamide resin hardly change even after a long boiling water treatment.
[Formula 4]

(Where R₁Is C_nH_2n(N = 1-3) hydrocarbon, R₂And R_ThreeIs H or C_nH_{2n + 1}(N = 1 to 3) hydrocarbon. )

Claims (3)

A polyamide resin comprising (A) a unit derived from a dicarboxylic acid and (B) a unit derived from a diamine, wherein the (A) dicarboxylic acid is derived from (A-1) 1,6-decanedicarboxylic acid. The diamine of (B) is a diamine represented by the structural formula (1), consisting of 50 to 100 mol% of the unit and (A-2) 0 to 50 mol% of the unit derived from isophthalic acid,

(Here, R ₁ is a hydrocarbon of C _n H _2n (n = 1 to 3), and R ₂ and R ₃ are H or a hydrocarbon of C _n H _{2n + 1} (n = 1 to 3).)
(Mole number of (A)): (Mole number of (B)) is 100: 95-100: 105, The transparent polyamide resin characterized by the above-mentioned.   (C) A polyamide resin comprising units derived from an aliphatic aminocarboxylic acid and / or lactam and (A) or (B) according to claim 1, wherein the total amount of (A) + (B) is 100. A transparent polyamide resin, wherein (C) is blended in a proportion of more than 0 mol and less than 30 mol with respect to mol.   When the transparent polyamide according to claim 1 or 2 is produced, it is polymerized until the number average molecular weight is in the range of 800 to 4,000 in the prepolymerization step, and the number average molecular weight is 7,000 to 30,000 in the post polymerization step. The method for producing a transparent polyamide resin according to claim 1, wherein polymerization is carried out until the range is satisfied.