JP3796904B2 - Process for producing polyphenylene sulfide - Google Patents
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- JP3796904B2 JP3796904B2 JP13902097A JP13902097A JP3796904B2 JP 3796904 B2 JP3796904 B2 JP 3796904B2 JP 13902097 A JP13902097 A JP 13902097A JP 13902097 A JP13902097 A JP 13902097A JP 3796904 B2 JP3796904 B2 JP 3796904B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、ポリフェニレンスルフィドの製造方法として、特に顆粒状の重合体を得る際に重合のサイクルを短縮しかつ未反応単量体の回収を容易にする方法に関するものであり、ポリフェニレンスルフィド製造の増能力、単量体の効率的回収による原単位削減により近年用途の拡大しつつある同重合体の供給安定化、産業廃棄物削減に貢献せんとするものである。
【０００２】
【従来の技術】
ポリフェニレンスルフィド（以下ＰＰＳと略す）はその高い耐熱性，耐薬品性、難燃性を活かし自動車部品や電気機器部品などに使用されるための射出成形用途やフィルム・繊維に使用されるための押出し用途に近年次第に需要が拡大しつつある。
【０００３】
ＰＰＳの製造方法は大別して２種類に区別でき、粉末状の重合体を得る方法と顆粒状の重合体を得る方法がある。前者は重合後半に、重合反応混合物を高温高圧でフラッシュし溶媒回収を容易ならしめんとする方法であり、後者は重合後半に重合反応混合物を徐冷しＰＰＳを顆粒状に回収する方法である。このＰＰＳの顆粒状の回収としては、例えば、特公平１−２５４９３号公報に示される相分離系の利用や、特開昭５９−４９２３２号公報あるいは特開平４−２５５７２２号公報に示されるように徐冷による顆粒状ＰＰＳの生成がある。またＰＰＳ収率向上に対しては、主に粉末状ＰＰＳ製造法ではあるが特開平４−２７５３３４号公報に記載されている重合途中での反応系のガス抜き方法があるが、顆粒状ＰＰＳの製造に於て更に生産性を向上させる方法が要求されているのが現状である。
【０００４】
【発明が解決しようとする課題】
本発明は、顆粒状ＰＰＳを製造する方法において、顆粒生成に長時間を要する過程を短縮し、その生産効率を向上せしめ、かつ重合反応混合物中から未反応単量体の回収を容易にする方法を提供することを課題とする。
【０００５】
【課題を解決するための手段】
すなわち本発明は、
（１）密閉した容器の中で、少なくとも１種の硫黄源およびポリハロ芳香族化合物を有機極性溶媒中で重合反応させ、重合反応後期に徐冷し、顆粒状のポリフェニレンスルフィドを製造する方法に於いて、重合反応後期に１８０〜２２０℃の範囲まで徐冷し、仕込み硫黄源に対し少なくとも５０モル％以上が固形顆粒状重合体で存在し、かつ、密閉した容器の圧力が０．３９×１０6 Ｐａ以上である状態で、容器を放圧して、ガス相と液相からなる重合反応混合物をガス抜きし、容器の圧力を０．２０×１０6 Ｐａ以上減圧することを特徴とするポリフェニレンスルフィドの製造方法、
（２）顆粒状のポリフェニレンスルフィドを製造する方法が、重合反応後期に液−液相分離させるとともに１８０〜２２０℃の範囲まで徐冷するものである上記（１）記載のポリフェニレンスルフィドの製造方法、
（３）前記硫黄源がアルカリ金属硫化物、ポリハロ芳香族化合物がジクロルベンゼンである上記（１）または（２）記載のポリフェニレンスルフィドの製造方法、
（４）重合体混合物中にアルカリ金属カルボキシレートを含有することを特徴とする上記（１）〜（３）のいずれか記載のポリフェニレンスルフィドの製造方法、および
（５）上記（１）〜（４）のいずれか記載のポリフェニレンスルフィドの製造方法によりポリフェニレンスルフィドを製造する際に、重合反応混合物をガス抜きすることにより、容器外へ留出した混合物から未反応ポリハロ芳香族化合物を回収することを特徴とするポリハロ芳香族化合物の回収方法である。
【０００６】
【発明の実施の形態】
本発明では、ＰＰＳ製造用の硫黄源として使用に適している化合物としては、アルカリ金属硫化物、アルカリ金属水硫化物、硫化水素及びそれらの混合物などが挙げられ、アルカリ金属水酸化物と併用することも都合良い。さらに具体的には硫化ナトリウム、水硫化ナトリウムと水酸化ナトリウム、硫化水素と水酸化ナトリウム等が挙げられる。また、分子量調整を目的とした助剤として、アルカリ金属カルボキシレート、スルホン酸塩、リチウム塩、水等の使用も可能である。
【０００７】
ポリハロ芳香族化合物としては、７０モル％以上はｐ−置換ハロゲン化ベンゼンであることが好ましく、特にｐ−ジクロルベンゼンが好都合に使用される。３０モル％未満の範囲では、共重合可能なｍ−、又はｏ−ジクロルベンゼン、トリクロルベンゼン、ビフェニル置換体、ナフタレン置換体も使用することができる。
【０００８】
重合反応に使用できる有機極性溶媒としては、有機アミド、ラクタム、尿素、スルホンおよびそれらの混合物などが挙げられるが、適当な溶媒の例として、Ｎ−メチル−２−ピロリドン、Ｎ−メチルカプロラクタム、ヘキサメチルホスホルアミド、テトラメチル尿素、１，３−ジメチル−２−イミダゾリジノン、１，４−ジメチル−２−ピペラジノンおよびそれら混合物がある。好適な溶媒としては、Ｎ−メチル−２−ピロリドンである。
【０００９】
本発明に於て、重合反応系中に仕込むポリハロ置換芳香族化合物の量は広い範囲にわたって変動できるが、好ましくは硫黄源１モル当り０．９０〜１．１０モルの範囲、さらに好ましくは０．９５〜１．０５モルの範囲で存在せしめることができる。このポリハロ芳香族化合物の導入は、硫黄源および有機極性溶媒混合物を脱水し、系内の含水率が硫黄源に対し０．３モル当量以下にされた後にされることが、得られるＰＰＳの分子量を増大させる点から適当である。
【００１０】
重合反応には密閉可能な容器を用い、重合反応後期にガス抜きするまでは容器を密閉した状態で重合反応を行なう。
【００１１】
重合反応を実施する反応温度は、通常２２０〜３７０℃、好ましくは２３０〜３５０℃の範囲であり、反応時間としては通常、１〜２０時間、好ましくは２〜１５時間の範囲内で行なわれる。用いる助剤の種類、量にもよるが、反応時間を適宜選択することにより、得られる重合体の分子量を適宜変動させることができる。
【００１２】
本発明において、顆粒状ＰＰＳとは１００メッシュ（１４９μｍ目開き）のフルイおよびフリィシュ(Fritsch）社製の“アナリセット(Analysette)”型振盪装置を用い、５分間振盪した際に補集される固形物を意味する。
【００１３】
顆粒状のＰＰＳは通常、重合反応後期に、ガス相と液相からなる重合反応混合物中の液相が液−液に相分離した系を徐冷中に得られるが、降温とともに顆粒部分が増大してくる。重合反応混合物中には有機極性溶媒、副生物としての水、その他故意に添加された水や低沸点副生物が存在し、かなりの高圧の反応系となる。ＰＰＳの品質に鑑み、重合中の溶媒は硫黄源１モル当り２〜８モルの範囲で使用されることが好ましいが、このような条件では、反応容器内の圧力は、徐冷中、２００℃でも０．５０×１０6 Ｐａ以上、１５０℃でも０．３５×１０6 Ｐａ以上を示すのが通常である。
【００１４】
上記において徐冷は、約１０℃／分よりも遅い速度で徐冷する方法が好ましい。従来、この徐冷は、重合反応混合物を、別の槽へ抜出す際、抜出し時の突沸、装置の振動等不都合な事態が発生しない程度、例えば１５０℃程度以下となるまで行なわれ、その後、別の槽へ抜出し、有機溶剤や水による洗浄が行なわれるが、重合のサイクルが長くなり、生産能力の低下をもたらしてしまう。徐冷の調整は通常反応容器ジャケットを冷却することにより行なわれるが、重合反応混合物の液相温度を約１０℃／分より遅い速度で冷却するよう外部ジャケットを調整して行なわれる。
【００１５】
上述のように顆粒状のＰＰＳは通常液−液に相分離している状態から得られるが、その相分離を増大せしめることは、顆粒状に回収される重合体の収率を向上させるのに有利である。この相分離を増大せしめるためにはアルカリ金属カルボキシレートや水等の助剤の存在が有効である。特に水に関しては重合途中、好ましくは硫黄源の転化率が８０％を越えた状態で添加することにより相分離を効果的にすることができる。
【００１６】
本発明の方法では、上記徐冷は、通常、密閉された容器を放圧することにより、重合反応混合物をガス抜きするまで行なう。好ましくは重合反応後期に２２０℃以上で重合反応が行なわれた後、２００℃以下となるまで徐冷する。ガス抜きは、重合体の少なくとも５０％以上、好ましくは６０％以上、さらに好ましくは７５％以上が固形顆粒状に存在し、圧力が０．３９×１０6 Ｐａ以上、好ましくは０．４５×１０6 Ｐａ以上、さらに好ましくは０．５０×１０6 Ｐａ以上の状態で放圧することにより行ない、それにより、圧力０．２０×１０6 Ｐａ以上減圧する。このガス抜きの操作により、その後の重合反応混合物の抜出し操作を容易にすると同時に、圧力低下のための外部からの冷却により従来長時間要していたこの冷却操作を短縮し重合反応のサイクルを短縮することが可能となる。このガス抜き時の温度は、固形顆粒状ＰＰＳが少なくとも５０％以上存在する状態で行なう必要があり通常、１８０〜２２０℃の範囲まで徐冷した段階で行なわれる。
【００１７】
放圧による減圧は０．２０×１０6Ｐａ以上、好ましくは０．２５×１０6以上行う。放圧による減圧が少なすぎると、反応器を封じてから解放する間でのサイクルの短縮の程度が小さくなる傾向にある。
【００１８】
固形顆粒状のＰＰＳの存在比率は、重合後期から徐冷途中の任意の温度で反応混合物を容器から抜出し弁を通しサンプリングし、未反応の硫黄源および顆粒状重合体量を直接定量することにより知ることが可能であるが通常、重合反応混合物中の溶媒、水、重合助剤の量および温度が決定されればほぼ予測することもできる。また圧力は、重合反応混合物中のガス相の圧力であり、反応容器内ガス相部に設置された圧力計感知部により知ることができる。
【００１９】
ガス抜きは、重合反応槽に付属した弁の開閉により調整する方法が便利であり、このガス抜きにより系内の温度が低下し重合反応混合物の抜出しには更に有利となる。弁の開閉は、ボール弁、ニードル弁型等の汎用の型式によりその開度を調整し、重合反応混合物の突沸を防止する速度で行なわれるが通常２０秒〜６０分、好ましくは１分〜５０分の時間でガス抜き操作を完了する。
【００２０】
ガス抜きにより系外へ導かれる物質は、未反応の単量体、水、低沸点有機物、一部の溶媒などであり、特にこれら混合物から未反応単量体、例えばｐ−ジクロルベンゼンなどのポリハロ芳香族化合物を固液分離又は蒸留により回収することを容易ならしめる。重合混合物をガス抜きするのに適切な方法は、公知の方法で行なうことが可能であり、例えば反応器に連結したバルブを操作することにより実施する。バルブを開放し、系外へ導かれた物質は、必要であれば冷却し、集められる。
【００２１】
本発明により製造した顆粒状ＰＰＳは、有機溶剤、水等による洗浄の後乾燥することができ、充填剤、顔料、他ポリマー等とブレンドし使用することも可能である。また単独に射出成形用や押出し用として使用することも可能である。場合によっては、酸化性の雰囲気下に加熱し硬化処理を加えることも可能である。
【００２２】
以下に実施例を挙げて本発明を更に詳細に説明する。
【００２３】
【実施例】
実施例および比較例の中で述べられる測定法について記述する。
【００２４】
メルトフローレート：ＡＳＴＭ Ｄ１２３８−８６に従って３１６℃、５Ｋｇの荷重にて測定した。
【００２５】
平均粒径：１００メッシュ（１４９μｍ目開き）、８０メッシュ、５０メッシュ、３０メッシュ、２０メッシュ、１０メッシュおよび４メッシュ（４．７６ｍｍ目開き）のフルイおよびフリィシュ(Fritsch）社製の“アナリセット(Analysette)”型振盪装置を用い、ＰＰＳ１００ｇ、カーボンブラック（粒径＜５０μｍ）１ｇを混合し、５分間振盪させ、各フルイ上の顆粒状ＰＰＳの重量から分布を算出し、重量分布の１／２点での粒径を平均粒径とした。
【００２６】
収率：得られたＰＰＳ樹脂のうち１００メッシュのフルイおよびフリィシュ(Fritsch）社製の“アナリセット(Analysette)”型振盪装置を用い、５分間の振盪により、補集されたＰＰＳの重量を理論値の重量で除して、その百分率を求めた。
【００２７】
比較例１（顆粒状ＰＰＳの製造−ガス抜きなし−）
１リットル容量のオートクレーブに、硫化ナトリウム（５水塩）１．０００モル、安息香酸ナトリウム０．２００モル、Ｎ−メチル−２−ピロリドン３．０モルを仕込み、窒素気流下２３０℃まで撹拌下に加熱し少量の溶媒を含有する留出水を除去した。留出水は４．８０モルを回収した。次に系内を１７５℃まで冷却し、固形状のｐ−ジクロルベンゼン０．９９５モルを０．５モルのＮ−メチル−２−ピロリドンとともに添加し系を封じ約０．８℃／分の昇温速度で２７０℃まで昇温し、その温度で２時間保持し、２７０℃一定に保持したまま高圧ポンプにより１．０モルの水を系内へ１０分間かけて添加した。この時圧力は１．５×１０6 Ｐａであった。次に１．０℃／分で１３０℃まで徐冷したがこの温度での圧力は０．１９×１０6 Ｐａを示していた。得られた顆粒状ＰＰＳは約７０℃のイオン交換水で７回洗浄後、１３０℃にて一昼夜真空乾燥した。なお洗浄、濾過は１５０メッシュの金網を使用した。
【００２８】
反応器を封じてから開放するまでのサイクルは７．５時間であり、収率８８％、メルトフローレート１３０ｇ／１０分の顆粒状ＰＰＳを得た。このときの平均粒径は１．２ｍｍであった。
【００２９】
実施例１（本発明によるガス抜き）
比較例１と同様な仕込み量、脱水、重合方法によりＰＰＳを合成したが反応器にはガス抜きを行なうため下部にボール弁付の開閉器を有する２００ｍｌ耐圧滴下ロートを付け上部はパイプを通して１０％水酸化ナトリウム水溶液中へ導く装置とした。２７０℃での保持、水添加を全く同様に操作し２００℃まで１℃／分で徐冷した。徐冷直前の圧力は１．５×１０6 Ｐａであり２００℃時点での圧力は０．８３×１０6 Ｐａであった。開閉弁を１分間かけて全開とし常圧にした。全開後の温度は１３０℃になり開閉弁上部のロート部には加熱された液状物が留出した。反応器中のＰＰＳは顆粒状であり比較例１と同様の水洗・乾燥を行なった。
【００３０】
反応器を封じてから開放するまでのサイクルは６．４時間であり、収率８８％、メルトフローレート１２５ｇ／１０分の顆粒ＰＰＳを得、また、平均粒径も１．２ｍｍと比較例１と同等であり、重合サイクル短縮により通常と同等以上のＰＰＳが得られることが確認できた。なおガス抜きにより留出した物質中には、約０．０１５モルのｐ−ジクロルベンゼン、１．７モルの水と少量の溶媒が検出され、ｐ−ジクロルベンゼンの回収に有利な混合物であることが判明した。
【００３１】
比較例２（高温、高圧下のガス抜き）
比較例１と同じ１リットルオートクレーブに、硫化ナトリウム（５水塩）１．０００モル、Ｎ−メチル−２−ピロリドン２．８モルを仕込み、窒素気流下２２０℃まで撹拌下に常圧下加熱し少量の溶媒を含む留出水４．７５モルを得た。系内を１７５℃まで冷却し、ｐ−ジクロルベンゼン０．９９０モルを０．３モルのＮ−メチル−２−ピロリドンとともに添加し、０．８℃／分の昇温速度で２７０℃まで昇温し、その温度で３時間保持した後２．２モルの水を高圧下に封入した。この時圧力は１．８×１０6 Ｐａとなっていた。次に２７０℃から２４０℃まで１℃／分で徐冷した後、実施例１記載の方法と同様にガス抜きを５分間かけて行ない内温を１４０℃、内圧を常圧まで低下させた。ＰＰＳの洗浄は比較例１と同様に行なった。
【００３２】
反応器を封じてから開放するまでのサイクルは５．０時間と短縮はされたが、ガス抜きの温度が高温であったため、ＰＰＳの顆粒状の収率は４５％であり、平均粒径も０．１ｍｍと小さいものであった。なおメルトフローレートは１６００ｇ／１０分であった。なおガス抜きにより得られた留出物中には０．０１８モルのｐ−ジクロルベンゼン、２．９モルの水、０．９５モルのＮ−メチル−２−ピロリドンが検出された。
【００３３】
実施例２（本発明によるガス抜き）
比較例２の操作を２００℃まで徐冷したことを除き同様に繰り返した。徐冷し２００℃に到達した時点での圧力は０．９５×１０6 Ｐａであった。１分間のガス抜きにより０．０１４モルのｐ−ジクロルベンゼン、３．０モルの水、少量の溶媒の留出物を得、系内は１３５℃、０．１０×１０6 Ｐａになった。
【００３４】
反応器を封じてからのサイクルは５．７時間であったが、ＰＰＳ収率は８９％、平均粒径０．９５ｍｍ、メルトフロー１６８０ｇ／１０分の顆粒状物を得た。なおガス抜きを行なわずに１３５℃まで外部から冷却する場合には７時間程のサイクルになる。
【００３５】
比較例３（パイロットスケールでの検討）
１００リットルの重合槽に硫化ナトリウム（５水塩）１００モル、安息香酸ナトリウム２０モル、Ｎ−メチルピロリドン３００モルを仕込み、窒素気流下２３０℃まで攪拌下に加熱し少量の溶媒を含有する留出水を除去した。留出水は４８０モルを回収した。次に系内を１７５℃まで冷却し、固形状のｐ−ジクロルベンゼン９９．５モルを５０モルのＮ−メチル−２−ピロリドンとともに添加し系を封じ約０．８℃／分の昇温速度で２７０℃まで昇温し、その温度で２時間保持し、２７０℃で一定に保持したまま高圧ポンプにより１００モルの水を系内へ３０分かけて添加した。このときの圧力は１．５×１０6 Ｐａであった。次に１．０℃／分で１３０℃まで徐冷したが、この温度での圧力は０．１９×１０6 Ｐａを示していた。得られた顆粒状ＰＰＳは約７０℃のイオン交換水で７回洗浄後、１３０℃にて一昼夜真空乾燥した。なを洗浄・濾過は１５０メッシュの金網を使用した。
【００３６】
重合槽に仕込みを開始してから開放するまでのサイクルは８．０時間であり、収率８９％、メルトフローレート１２９ｇ／１０分の顆粒状ＰＰＳを得た。このときの平均粒径は１．３ｍｍであった。
【００３７】
実施例３（パイロットスケールでのガス抜き）
比較例３と同様な仕込み量、脱水、重合方法によりＰＰＳを合成し、２７０℃での保持、水添加を全く同様に操作し、２００℃まで１℃／分で徐冷した。徐冷直前の圧力は１．７×１０6 Ｐａであり、２００℃時点での圧力は０．８６×１０6 Ｐａであった。開閉弁を開け３０分かけてガス抜きを行い、系内は０．３５×１０6 Ｐａ、１３２℃になった。重合槽中のＰＰＳは顆粒状であり、比較例３と同様の水洗・乾燥を行った。
【００３８】
重合槽に仕込みを開始してから解放するまでのサイクルは６．８時間であり、収率８８％、メルトフローレート１２５ｇ／１０分の顆粒状ＰＰＳを得、また平均粒径も１．２ｍｍであった。このようにパイロットスケールにおいても重合サイクルの短縮が図られ、かつ比較例３と同等以上のＰＰＳが得られることが確認できた。なお、ガス抜きにより留出した物質中には、約１．５モルのｐ−ジクロルベンゼンが含まれており、ｐ−ジクロルベンゼンの回収に有効であった。
【００３９】
【発明の効果】
本発明のポリフェニレンスルフィドの製造方法により、顆粒状ＰＰＳを短縮されたサイクルで提供可能となり、さらに未反応単量体の回収を容易ならしめることが可能となる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing polyphenylene sulfide, particularly to a method for shortening a polymerization cycle and facilitating recovery of unreacted monomers when obtaining a granular polymer. It is intended to contribute to the stabilization of the supply of the same polymer and the reduction of industrial waste, which are expanding its use in recent years by reducing the basic unit by efficient recovery of capacity and monomers.
[0002]
[Prior art]
Polyphenylene sulfide (hereinafter abbreviated as PPS) utilizes its high heat resistance, chemical resistance, and flame resistance, and is used for injection molding applications such as automotive parts and electrical equipment parts, and extrusion for use in films and fibers. In recent years, the demand for use has been gradually expanding.
[0003]
PPS production methods can be broadly divided into two types: a method for obtaining a powdery polymer and a method for obtaining a granular polymer. The former is a method in which the polymerization reaction mixture is flushed at high temperature and high pressure in the latter half of the polymerization to facilitate solvent recovery, and the latter is a method in which the polymerization reaction mixture is gradually cooled in the latter half of the polymerization to recover PPS in the form of granules. . Examples of the recovery of the granular form of PPS include use of a phase separation system disclosed in Japanese Patent Publication No. 1-25493, and Japanese Patent Application Laid-Open No. 59-49232 or Japanese Patent Application Laid-Open No. 4-255722. There is generation of granular PPS by slow cooling. For improving the PPS yield, there is a method of venting the reaction system in the middle of polymerization described in JP-A-4-275334, which is mainly a powdered PPS production method. At present, there is a demand for a method for further improving productivity in manufacturing.
[0004]
[Problems to be solved by the invention]
The present invention relates to a method for producing granular PPS, which shortens a process that takes a long time to produce granules, improves its production efficiency, and facilitates recovery of unreacted monomers from the polymerization reaction mixture. It is an issue to provide.
[0005]
[Means for Solving the Problems]
That is, the present invention
(1) In a method for producing granular polyphenylene sulfide by polymerizing at least one sulfur source and a polyhaloaromatic compound in an organic polar solvent in a sealed container and slowly cooling in the latter stage of the polymerization reaction. In the latter stage of the polymerization reaction, it is gradually cooled to the range of 180 to 220 ° C., at least 50 mol% or more of the solid sulfur polymer is present with respect to the charged sulfur source, and the pressure in the sealed container is 0.39 × 10 A polyphenylene sulfide characterized by releasing the pressure of the container in a state of 6 Pa or more, degassing the polymerization reaction mixture composed of a gas phase and a liquid phase, and reducing the pressure of the container to 0.20 × 10 6 Pa or more. Manufacturing method,
(2) method, the polymerization reaction late liquid to produce a granular polyphenylene sulfide - is to slow cooling to a range of 180 to 220 ° C. causes liquid phase separation above (1) Symbol method for producing polyphenylene sulfide mounting ,
( 3 ) The method for producing polyphenylene sulfide according to the above (1) or (2 ), wherein the sulfur source is an alkali metal sulfide and the polyhaloaromatic compound is dichlorobenzene,
( 4 ) The method for producing polyphenylene sulfide according to any one of (1) to ( 3 ) above, wherein the polymer mixture contains an alkali metal carboxylate, and ( 5 ) the above (1) to ( 4 When the polyphenylene sulfide is produced by the method for producing polyphenylene sulfide according to any one of the above), the unreacted polyhaloaromatic compound is recovered from the mixture distilled out of the container by degassing the polymerization reaction mixture. And a method for recovering the polyhaloaromatic compound.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, compounds suitable for use as a sulfur source for PPS production include alkali metal sulfides, alkali metal hydrosulfides, hydrogen sulfide, and mixtures thereof, and are used in combination with alkali metal hydroxides. It is also convenient. More specifically, sodium sulfide, sodium hydrosulfide and sodium hydroxide, hydrogen sulfide and sodium hydroxide and the like can be mentioned. In addition, alkali metal carboxylate, sulfonate, lithium salt, water or the like can be used as an auxiliary agent for adjusting the molecular weight.
[0007]
As the polyhaloaromatic compound, 70 mol% or more is preferably p-substituted halogenated benzene, and p-dichlorobenzene is particularly preferably used. In the range of less than 30 mol%, copolymerizable m- or o-dichlorobenzene, trichlorobenzene, biphenyl substituted product, naphthalene substituted product can also be used.
[0008]
Organic polar solvents that can be used in the polymerization reaction include organic amides, lactams, ureas, sulfones, and mixtures thereof. Examples of suitable solvents include N-methyl-2-pyrrolidone, N-methylcaprolactam, hexa There are methylphosphoramide, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, 1,4-dimethyl-2-piperazinone and mixtures thereof. A suitable solvent is N-methyl-2-pyrrolidone.
[0009]
In the present invention, the amount of the polyhalo-substituted aromatic compound charged into the polymerization reaction system can vary over a wide range, but is preferably in the range of 0.90 to 1.10 moles per mole of sulfur source, more preferably 0.8. It can be present in the range of 95 to 1.05 mol. The introduction of the polyhaloaromatic compound is performed after dehydration of the sulfur source and the organic polar solvent mixture and the water content in the system is reduced to 0.3 molar equivalent or less with respect to the sulfur source. It is appropriate from the viewpoint of increasing the value.
[0010]
For the polymerization reaction, a sealable container is used, and the polymerization reaction is performed in a state where the container is sealed until the gas is vented at the latter stage of the polymerization reaction.
[0011]
The reaction temperature for carrying out the polymerization reaction is usually in the range of 220 to 370 ° C, preferably 230 to 350 ° C, and the reaction time is usually 1 to 20 hours, preferably 2 to 15 hours. Although depending on the type and amount of the auxiliary agent used, the molecular weight of the resulting polymer can be appropriately varied by appropriately selecting the reaction time.
[0012]
In the present invention, granular PPS is a solid that is collected when shaken for 5 minutes using a 100 mesh (149 μm opening) sieve and a “Analysette” type shaker manufactured by Fritsch. Means a thing.
[0013]
Granular PPS is usually obtained during the slow cooling of a system in which the liquid phase in the polymerization reaction mixture consisting of a gas phase and a liquid phase is phase-separated into a liquid-liquid phase in the late stage of the polymerization reaction. come. In the polymerization reaction mixture, an organic polar solvent, water as a by-product, other intentionally added water and a low-boiling by-product are present, resulting in a considerably high-pressure reaction system. In view of the quality of PPS, the solvent during polymerization is preferably used in the range of 2 to 8 moles per mole of sulfur source. Under such conditions, the pressure in the reaction vessel is 0 even at 200 ° C. during slow cooling. It is usually 50 × 10 6 Pa or more, and usually 0.35 × 10 6 Pa or more even at 150 ° C.
[0014]
In the above, slow cooling is preferably a method of slow cooling at a rate slower than about 10 ° C./min. Conventionally, this slow cooling is performed until an unfavorable situation such as bumping at the time of extraction and vibration of the apparatus does not occur when the polymerization reaction mixture is extracted into another tank, for example, about 150 ° C. or less, and then Although it is extracted to another tank and washed with an organic solvent or water, the polymerization cycle becomes long and the production capacity is reduced. The slow cooling is usually adjusted by cooling the reaction vessel jacket, but by adjusting the outer jacket so as to cool the liquid phase temperature of the polymerization reaction mixture at a rate slower than about 10 ° C./min.
[0015]
As described above, granular PPS is usually obtained from a liquid-liquid phase separation. Increasing the phase separation improves the yield of the polymer recovered in the granular form. It is advantageous. In order to increase the phase separation, the presence of an auxiliary such as alkali metal carboxylate or water is effective. In particular, with respect to water, phase separation can be made effective by adding during polymerization, preferably in a state where the conversion rate of the sulfur source exceeds 80%.
[0016]
In the method of the present invention, the slow cooling is usually performed until the polymerization reaction mixture is degassed by releasing the pressure in a sealed container. Preferably, after the polymerization reaction is performed at 220 ° C. or higher in the latter stage of the polymerization reaction, it is gradually cooled to 200 ° C. or lower. In the degassing, at least 50% or more, preferably 60% or more, more preferably 75% or more of the polymer is present in the form of solid granules, and the pressure is 0.39 × 10 6 Pa or more, preferably 0.45 × 10. It is carried out by releasing the pressure in a state of 6 Pa or more, more preferably 0.50 × 10 6 Pa or more, whereby the pressure is reduced to 0.20 × 10 6 Pa or more. This degassing operation facilitates the subsequent extraction of the polymerization reaction mixture, and at the same time shortens this cooling operation, which was previously required for a long time by external cooling for pressure reduction, and shortens the cycle of the polymerization reaction. It becomes possible to do. The degassing temperature needs to be performed in a state where at least 50% or more of the solid granular PPS is present, and is usually performed at a stage where it is gradually cooled to a range of 180 to 220 ° C.
[0017]
Depressurization by releasing pressure is 0.20 × 10 6 Pa or more, preferably 0.25 × 10 6 or more. If the pressure reduction due to the release pressure is too small, the degree of cycle shortening after the reactor is sealed and then released tends to be small.
[0018]
The abundance ratio of solid granular PPS is determined by sampling the reaction mixture from the container at an arbitrary temperature during the late polymerization to the slow cooling, sampling through the valve, and directly quantifying the amount of unreacted sulfur source and granular polymer. Although it is possible to know, generally it can be almost predicted if the amount of solvent, water, polymerization aid and temperature in the polymerization reaction mixture are determined. The pressure is the pressure of the gas phase in the polymerization reaction mixture, and can be known from a pressure gauge sensing unit installed in the gas phase part in the reaction vessel.
[0019]
The degassing is conveniently adjusted by opening and closing a valve attached to the polymerization reaction tank, and this degassing lowers the temperature in the system, which is further advantageous for extracting the polymerization reaction mixture. The opening and closing of the valve is carried out at a speed that adjusts the opening degree by a general-purpose type such as a ball valve or a needle valve type to prevent bumping of the polymerization reaction mixture, but is usually 20 seconds to 60 minutes, preferably 1 minute to 50. Complete the degassing operation in minutes.
[0020]
Substances led out of the system by degassing are unreacted monomers, water, low-boiling organic substances, some solvents, etc., and particularly unreacted monomers such as p-dichlorobenzene from these mixtures. It makes it easy to recover the polyhaloaromatic compound by solid-liquid separation or distillation. Suitable methods for degassing the polymerization mixture can be carried out by known methods, for example by operating a valve connected to the reactor. The material that opens the valve and is led out of the system is cooled and collected if necessary.
[0021]
The granular PPS produced according to the present invention can be dried after washing with an organic solvent, water or the like, and can also be used by blending with a filler, a pigment, other polymers and the like. It can also be used alone for injection molding or extrusion. In some cases, it is possible to apply a curing treatment by heating in an oxidizing atmosphere.
[0022]
Hereinafter, the present invention will be described in more detail with reference to examples.
[0023]
【Example】
The measurement methods described in the examples and comparative examples are described.
[0024]
Melt flow rate: Measured in accordance with ASTM D1238-86 at a load of 316 ° C. and 5 kg.
[0025]
Average particle size: 100 mesh (149 μm opening), 80 mesh, 50 mesh, 30 mesh, 20 mesh, 10 mesh and 4 mesh (4.76 mm opening) “Flysch” “Analyst ( Analysette) ”type shaker, 100 g of PPS and 1 g of carbon black (particle size <50 μm) were mixed and shaken for 5 minutes, and the distribution was calculated from the weight of the granular PPS on each sieve. The particle size at the point was defined as the average particle size.
[0026]
Yield: The weight of the collected PPS was calculated by shaking for 5 minutes using a 100-mesh sieve and “Analysette” shaker manufactured by Fritsch. The percentage was determined by dividing by the weight of the value.
[0027]
Comparative Example 1 (Production of granular PPS-no venting)
A 1 liter autoclave was charged with 1.000 moles of sodium sulfide (pentahydrate), 0.200 moles of sodium benzoate and 3.0 moles of N-methyl-2-pyrrolidone, and stirred under a nitrogen stream up to 230 ° C. Distilled water containing a small amount of solvent was removed by heating. Distilled water recovered 4.80 mol. Next, the system was cooled to 175 ° C., 0.995 mol of solid p-dichlorobenzene was added together with 0.5 mol of N-methyl-2-pyrrolidone, the system was sealed, and about 0.8 ° C./min. The temperature was raised to 270 ° C. at a rate of temperature rise, held at that temperature for 2 hours, and 1.0 mol of water was added to the system over 10 minutes with a high-pressure pump while keeping the temperature constant at 270 ° C. At this time, the pressure was 1.5 × 10 6 Pa. Next, it was gradually cooled to 130 ° C. at 1.0 ° C./min, and the pressure at this temperature was 0.19 × 10 6 Pa. The obtained granular PPS was washed 7 times with ion-exchanged water at about 70 ° C. and then vacuum-dried at 130 ° C. for a whole day and night. Washing and filtration used a 150 mesh wire mesh.
[0028]
The cycle from sealing the reactor to opening was 7.5 hours, and a granular PPS with a yield of 88% and a melt flow rate of 130 g / 10 min was obtained. The average particle diameter at this time was 1.2 mm.
[0029]
Example 1 (gas venting according to the invention)
PPS was synthesized by the same charging amount, dehydration, and polymerization method as in Comparative Example 1, but the reactor was degassed with a 200 ml pressure drop funnel having a ball valve-equipped switch at the top and 10% through the pipe at the top. The apparatus led to an aqueous sodium hydroxide solution. The holding at 270 ° C. and the addition of water were performed in exactly the same manner and gradually cooled to 200 ° C. at 1 ° C./min. The pressure immediately before the slow cooling was 1.5 × 10 6 Pa, and the pressure at 200 ° C. was 0.83 × 10 6 Pa. The on-off valve was fully opened over 1 minute to normal pressure. The temperature after full opening became 130 ° C., and the heated liquid substance was distilled off in the funnel part above the on-off valve. The PPS in the reactor was granular and was washed and dried in the same manner as in Comparative Example 1.
[0030]
The cycle from sealing of the reactor to opening was 6.4 hours, yielding a granular PPS with a yield of 88% and a melt flow rate of 125 g / 10 min, and an average particle size of 1.2 mm. It was confirmed that PPS equivalent to or higher than usual can be obtained by shortening the polymerization cycle. In the substance distilled by degassing, about 0.015 mol of p-dichlorobenzene, 1.7 mol of water and a small amount of solvent were detected, and this was a mixture advantageous for the recovery of p-dichlorobenzene. It turned out to be.
[0031]
Comparative example 2 (degassing under high temperature and high pressure)
A 1-liter autoclave as in Comparative Example 1 was charged with 1.000 moles of sodium sulfide (pentahydrate) and 2.8 moles of N-methyl-2-pyrrolidone, heated to 220 ° C. with stirring under normal pressure and a small amount. 4.75 mol of distilled water containing the above solvent was obtained. The system was cooled to 175 ° C., 0.990 mol of p-dichlorobenzene was added together with 0.3 mol of N-methyl-2-pyrrolidone, and the temperature was increased to 270 ° C. at a rate of 0.8 ° C./min. After warming and holding at that temperature for 3 hours, 2.2 mol of water was sealed under high pressure. At this time, the pressure was 1.8 × 10 6 Pa. Next, after gradual cooling from 270 ° C. to 240 ° C. at 1 ° C./min, degassing was performed for 5 minutes in the same manner as in Example 1 to lower the internal temperature to 140 ° C. and the internal pressure to normal pressure. PPS was washed in the same manner as in Comparative Example 1.
[0032]
Although the cycle from sealing the reactor to opening was shortened to 5.0 hours, the degassing temperature was high, so the granular yield of PPS was 45% and the average particle size was also It was as small as 0.1 mm. The melt flow rate was 1600 g / 10 minutes. In the distillate obtained by degassing, 0.018 mol of p-dichlorobenzene, 2.9 mol of water, and 0.95 mol of N-methyl-2-pyrrolidone were detected.
[0033]
Example 2 (gas venting according to the invention)
The operation of Comparative Example 2 was repeated in the same manner except that the operation was gradually cooled to 200 ° C. The pressure when it was gradually cooled and reached 200 ° C. was 0.95 × 10 6 Pa. By degassing for 1 minute, a distillate of 0.014 mol of p-dichlorobenzene, 3.0 mol of water and a small amount of solvent was obtained, and the temperature in the system became 135 ° C. and 0.10 × 10 6 Pa. .
[0034]
The cycle after the reactor was sealed was 5.7 hours, but a PPS yield of 89%, an average particle size of 0.95 mm, and a melt flow of 1680 g / 10 min were obtained. In the case of cooling from the outside to 135 ° C. without degassing, the cycle is about 7 hours.
[0035]
Comparative Example 3 (Pilot scale study)
A 100 liter polymerization tank is charged with 100 moles of sodium sulfide (pentahydrate), 20 moles of sodium benzoate and 300 moles of N-methylpyrrolidone, heated to 230 ° C. with stirring under a nitrogen stream, and containing a small amount of solvent. Water was removed. Distilled water recovered was 480 mol. Next, the system was cooled to 175 ° C., 99.5 mol of solid p-dichlorobenzene was added together with 50 mol of N-methyl-2-pyrrolidone, the system was sealed, and the temperature was raised to about 0.8 ° C./min. The temperature was raised to 270 ° C. at a rate, maintained at that temperature for 2 hours, and 100 mol of water was added to the system over 30 minutes with a high-pressure pump while keeping the temperature constant at 270 ° C. The pressure at this time was 1.5 × 10 6 Pa. Next, it was gradually cooled to 130 ° C. at 1.0 ° C./min, and the pressure at this temperature was 0.19 × 10 6 Pa. The obtained granular PPS was washed 7 times with ion-exchanged water at about 70 ° C. and then vacuum-dried at 130 ° C. for a whole day and night. For washing and filtration, a 150 mesh wire mesh was used.
[0036]
The cycle from the start of charging into the polymerization tank to the release was 8.0 hours, and a granular PPS with a yield of 89% and a melt flow rate of 129 g / 10 min was obtained. The average particle size at this time was 1.3 mm.
[0037]
Example 3 (Degassing on pilot scale)
PPS was synthesized by the same charging amount, dehydration, and polymerization method as in Comparative Example 3, and maintained at 270 ° C. and water addition were operated in exactly the same manner and gradually cooled to 200 ° C. at 1 ° C./min. The pressure immediately before slow cooling was 1.7 × 10 6 Pa, and the pressure at 200 ° C. was 0.86 × 10 6 Pa. The on-off valve was opened and degassed over 30 minutes, and the inside of the system became 0.35 × 10 6 Pa, 132 ° C. The PPS in the polymerization tank was granular and washed and dried in the same manner as in Comparative Example 3.
[0038]
The cycle from the start of charging to the polymerization tank to release is 6.8 hours, yielding a granular PPS with a yield of 88% and a melt flow rate of 125 g / 10 min, and an average particle size of 1.2 mm. there were. Thus, it was confirmed that the polymerization cycle was shortened even on the pilot scale, and that PPS equivalent to or higher than that of Comparative Example 3 was obtained. In addition, in the substance distilled by degassing, about 1.5 mol of p-dichlorobenzene was contained, and it was effective in the recovery of p-dichlorobenzene.
[0039]
【The invention's effect】
According to the method for producing polyphenylene sulfide of the present invention, granular PPS can be provided in a shortened cycle, and the recovery of unreacted monomers can be facilitated.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13902097A JP3796904B2 (en) | 1996-06-06 | 1997-05-28 | Process for producing polyphenylene sulfide |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8-144285 | 1996-06-06 | ||
| JP14428596 | 1996-06-06 | ||
| JP13902097A JP3796904B2 (en) | 1996-06-06 | 1997-05-28 | Process for producing polyphenylene sulfide |
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| Publication Number | Publication Date |
|---|---|
| JPH1087831A JPH1087831A (en) | 1998-04-07 |
| JP3796904B2 true JP3796904B2 (en) | 2006-07-12 |
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| JP5196458B2 (en) * | 1999-07-21 | 2013-05-15 | 東レ株式会社 | Method for producing granular polyarylene sulfide resin |
| KR20010044212A (en) * | 2001-01-04 | 2001-06-05 | 김창수 | Process for producing linear high molecular weight polyphenylene sulfide |
| DE60236529D1 (en) | 2001-09-27 | 2010-07-08 | Kureha Corp | METHOD FOR PRODUCING POLYARYLENEULFIDE |
| JP3989785B2 (en) * | 2002-07-18 | 2007-10-10 | 株式会社クレハ | Process for producing polyarylene sulfide |
| US7312300B2 (en) * | 2005-02-22 | 2007-12-25 | Chevron Phillips Chemical Company Lp | Inferred water analysis in polyphenylene sulfide production |
| US8609790B2 (en) | 2008-07-31 | 2013-12-17 | Kureha Corporation | Production process of granular poly(arylene sulfide) |
| JP2010144085A (en) * | 2008-12-19 | 2010-07-01 | Tosoh Corp | Process for producing polyphenylene sulfide |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4415729A (en) * | 1982-06-04 | 1983-11-15 | Phillips Petroleum Company | Recovering granular poly(arylene sulfide) particles from a poly(arylene sulfide) reaction mixture |
| JPS5949232A (en) * | 1982-09-14 | 1984-03-21 | Toray Ind Inc | Manufacture of polyphenylene sulfide |
| US5200499A (en) * | 1990-11-29 | 1993-04-06 | Phillips Petroleum Company | Removal of water by venting during the polymerization of phenylene sulfide polymers with sulfur source/polar organic compound molar ratio being at least 0.36/1 |
| JPH0543691A (en) * | 1991-08-14 | 1993-02-23 | Tosoh Corp | Polyarylene thioether excellent in ductility and production of the same |
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| JPH1087831A (en) | 1998-04-07 |
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