JP2004010902A - Method for producing polyamide resin from caprolactam - Google Patents
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本発明は、すぐれた品質のポリアミド樹脂をカプロラクタムより工業的に効率よく製造する方法に関する。 The present invention relates to a method for industrially and efficiently producing a polyamide resin of excellent quality from caprolactam.
カプロラクタムの重合によって得られるポリアミド樹脂中には、１０重量％程度の未反応カプロラクタム及びその低重合物（以下「オリゴマー」という）が含まれているので、製品とするには、熱水抽出によりオリゴマーを除去することが必要である。 The polyamide resin obtained by polymerization of caprolactam contains about 10% by weight of unreacted caprolactam and its low polymer (hereinafter referred to as “oligomer”). Need to be removed.
熱水抽出によって得られるオリゴマーを含有する希薄水溶液の処理法としては、これを精製又は濃縮して重合反応系に供給し、これに新しいカプロラクタムを追加して重合させる方法が知られている。例えば、特公昭４０−１５６６３号公報には、オリゴマー水溶液をイオン交換剤により精製したものにオリゴマー１重量部当り６〜５００重量部の新しいカプロラクタムを加えて重合させる方法が示されている。 As a method of treating a dilute aqueous solution containing an oligomer obtained by hot water extraction, a method of purifying or concentrating the diluted aqueous solution, supplying the diluted aqueous solution to a polymerization reaction system, and adding new caprolactam to the polymerization solution for polymerization is known. For example, Japanese Patent Publication No. 40-15663 discloses a method in which an aqueous solution of an oligomer is purified with an ion exchange agent, and 6 to 500 parts by weight of new caprolactam is added to 1 part by weight of the oligomer to carry out polymerization.
カプロラクタムの重合に際しては、適量の水分を存在させて加圧下、カプロラクタムを加水分解し、次いで放圧して水分を除き、常圧ないし減圧下で重合させる。その場合、当初の水分量があまりに多いと放圧時の熱損失が大きく、また装置も大型となって工業的に有利ではないので、通常はカプロラクタムに対し数％程度の水分が存在する状態で重合させるが、上記特公昭４０−１５６６３号公報の方法によるときは、オリゴマーの希薄水溶液中の水分に見合う比較的多量のカプロラクタムを加えないと、適当な水分量を保持しえないので、工業的製造法としては満足し得るものではない。 In the polymerization of caprolactam, caprolactam is hydrolyzed under pressure in the presence of an appropriate amount of water, then the pressure is released to remove water, and polymerization is carried out under normal pressure or reduced pressure. In such a case, if the initial water content is too large, heat loss at the time of pressure release is large, and the device becomes large, which is not industrially advantageous. Polymerization is carried out, but in the case of the method disclosed in Japanese Patent Publication No. 40-15663, an appropriate amount of water cannot be maintained unless a relatively large amount of caprolactam corresponding to the water in a dilute aqueous solution of the oligomer is added. It is not satisfactory as a manufacturing method.
また、特開昭５１−９６８９１号公報には、濃縮オリゴマーを分離又は精製することなく、他のポリアミド原料と一緒に重合させることが示され、オリゴマーの濃縮は、９０重量％以上、好ましくは９６重量％以上、特に好ましくは９８重量％まで濃縮し、該濃縮物を固化した薄片として、重合反応系に供することが示されている。しかしながら、９０重量％を超えるような高濃度のオリゴマー濃縮物は粘度が大きく取扱いが困難であり、また、一旦固化したオリゴマーは重合反応系内で容易に溶解せず、製品にフィッシュアイを生成させる原因となる等の不都合がある。しかも、オリゴマーを含有する濃縮物中の水分が微量であると、重合反応系に別途水分を供給する必要があって、工業的に有利な方法とはいえない。 JP-A-51-96891 discloses that a concentrated oligomer is polymerized together with another polyamide raw material without separation or purification, and the concentration of the oligomer is 90% by weight or more, preferably 96% by weight or more. It is disclosed that the solution is concentrated to not less than 98% by weight, particularly preferably to 98% by weight, and the concentrate is supplied to a polymerization reaction system as solidified flakes. However, a high-concentration oligomer concentrate having a concentration of more than 90% by weight has a large viscosity and is difficult to handle, and the oligomer once solidified is not easily dissolved in the polymerization reaction system, and causes a fisheye to be formed in the product. There are inconveniences such as cause. In addition, if the amount of water in the concentrate containing the oligomer is very small, it is necessary to separately supply water to the polymerization reaction system, which is not an industrially advantageous method.
更に、特開昭５４−６４５９３号公報には、オリゴマーを８０〜９０重量％まで濃縮するに際し、温度ｔ≧６Ｃ−３２０（Ｃ：濃縮度：重量％）に保持し、溶融状態で重合反応器にリサイクルすることが示されている。しかし同公報には、特に最も開環し難い環状ダイマーが開環することの明示はなく、後述する実施例で示すように、同公報の実施例の濃縮条件下では環状ダイマーはほとんど開環しない。更に、濃縮をより高温で行うことは、同一の圧力下において、濃縮度を下げる結果となるが、同公報においては、濃縮度を８０〜９０％としなくてはならないので、濃縮度が９０％に近い上記実施例において更に高温にするとの思想はないと考えられる。
本発明者らの知見によれば、この開環し難い環状ダイマーが重合反応器に供給され、追加量のカプロラクタムと重合工程にリサイクルされると、一定の平衡値に到達するまで増加し、結果的に製品中に多くの環状ダイマーが含有されることとなる。環状ダイマーは、融点も高く（３００℃以上）昇華性があり、成形加工時昇華し、金型に付着したり（射出成形）、ダイスに付着したり（押出成形）して、多くのトラブルを引き起こす原因物質となる。
Further, Japanese Patent Application Laid-Open No. 54-64593 discloses that, when an oligomer is concentrated to 80 to 90% by weight, a temperature t ≧ 6C-320 (C: degree of concentration:% by weight) is maintained, and the polymerization reactor is melted. To be recycled. However, the publication does not specifically indicate that the most difficult ring-opening cyclic dimer opens, and as shown in the examples described below, the cyclic dimer hardly opens under the enrichment conditions of the examples of the publication. . Further, performing the concentration at a higher temperature results in lowering the concentration under the same pressure. However, in the same publication, since the concentration must be 80 to 90%, the concentration is 90%. It is considered that there is no idea that the temperature is further increased in the above-described embodiment close to the above.
According to the findings of the present inventors, when this hard-to-open cyclic dimer is supplied to the polymerization reactor and recycled to the polymerization step with an additional amount of caprolactam, it increases until a certain equilibrium value is reached, and the result is As a result, many cyclic dimers will be contained in the product. The cyclic dimer has a high melting point (300 ° C. or higher) and sublimation, sublimates during molding, and adheres to a mold (injection molding) or a die (extrusion molding), causing many troubles. It is a causative substance.
本発明は、上記の問題を解決し、カプロラクタムより工業的に効率よく、高品質のポリアミド樹脂を製造する方法を提供することを目的とする。 An object of the present invention is to solve the above problems and to provide a method for producing a high-quality polyamide resin industrially more efficiently than caprolactam.
本発明者らは、このため鋭意検討を重ねた結果、環状オリゴマーのうち特に開環しにくい環状ダイマーを開環させるのが重要であり、同環状ダイマーを開環させる条件として、特に水分圧と温度が重要な因子であることを見出し、本発明を完成した。 The present inventors have conducted intensive studies for this reason, and as a result, it is important to open a ring dimer which is particularly difficult to open among the cyclic oligomers. Conditions for opening the ring dimer include, in particular, water pressure and water pressure. The inventors have found that temperature is an important factor, and have completed the present invention.
すなわち本発明は、水の存在下、カプロラクタムを重合させて得られるポリアミド樹脂を水抽出して、得られる未反応のカプロラクタム及びその低重合物を含有する水溶液を濃縮し、該濃縮物に追加量のカプロラクタムを添加して重合させるポリアミド樹脂の製造方法において、
（１）前記水溶液中環状オリゴマーのうち、環状ダイマーを１５％以上開環、鎖状体とした後、重合反応器に供給し、次いで
（２）前記追加量のカプロラクタムを添加する、
ことを繰返すことを特徴とするカプロラクタムよりポリアミド樹脂を製造する方法である。
That is, in the present invention, in the presence of water, the polyamide resin obtained by polymerizing caprolactam is extracted with water, the resulting aqueous solution containing unreacted caprolactam and its low polymer is concentrated, and the added amount is added to the concentrate. In the method for producing a polyamide resin to be polymerized by adding caprolactam,
(1) Of the cyclic oligomers in the aqueous solution, the cyclic dimer is opened to a ring by 15% or more to form a chain, and then supplied to a polymerization reactor. (2) The additional amount of caprolactam is added.
This is a method for producing a polyamide resin from caprolactam, characterized by repeating the above.
以下、本発明を詳細に説明する。
本発明のポリアミド樹脂の製造には、通常ε−カプロラクタムが原料として使用される。更にε−カプロラクタムを主成分として、これと共重合し得る成分、例えば１１−アミノウンデカン酸、ヘキサメチレンジアミン−アジピン酸塩、ヘキサメチレンジアミン−セバシン酸塩、ヘキサメチレンジアミン−アゼライン酸塩、ヘキサメチレンジアミン−テレフタル酸塩、イソホロンジアミン−アジピン酸塩のようなラクタム類、又はジアミンとジカルボン酸の塩を共重合させて得られる共重合ポリアミドを包含する。
Hereinafter, the present invention will be described in detail.
In the production of the polyamide resin of the present invention, ε-caprolactam is usually used as a raw material. Further, ε-caprolactam as a main component and a component copolymerizable therewith, for example, 11-aminoundecanoic acid, hexamethylenediamine-adipate, hexamethylenediamine-sebacate, hexamethylenediamine-azeleate, hexamethylene Lactams such as diamine-terephthalate and isophoronediamine-adipate, or copolymerized polyamides obtained by copolymerizing a salt of a diamine and a dicarboxylic acid are included.
これらポリアミドは、通常カプロラクタムを水の存在下２０kg/cm2G 以下、好ましくは３〜１０kg/cm2G の圧力、２４０〜２９０℃の温度で加水分解により開環させ、次いで放圧し、同程度の温度で常圧ないし数十Torrまでの減圧下重縮合させて得られる。 These polyamides are normally caprolactam less presence 20 kg / cm 2 G of water, preferably at a pressure of 3~10kg / cm 2 G, by ring-opening by hydrolysis at a temperature of two hundred forty to two hundred ninety ° C., then depressurized, comparable At a temperature of normal pressure to several tens of Torr under reduced pressure.
オリゴマーの抽出は公知の方法が採用でき、熱水単独、カプロラクタムや安定剤等を含有する熱水等が用いられる。抽出操作としては、熱水を用いる数段の抽出操作が好ましい。 The oligomer can be extracted by a known method, for example, hot water alone or hot water containing caprolactam or a stabilizer is used. As the extraction operation, a several-stage extraction operation using hot water is preferable.
本発明の重要な点の１つは、上記のようにして得られた水溶液中の環状ダイマーを１５％以上開環させることにある。開環させる条件に特に制限はないが、以下に述べる濃縮工程において開環させることが好ましい。
抽出オリゴマー水溶液の濃縮には、多段濃縮法等周知の濃縮方法がいずれも適用できるが、通常オリゴマー濃度として７０〜９８重量％、好ましくは７５〜９５重量％まで濃縮する。圧力は１０〜３０kg/cm2G 、好ましくは１０〜２０kg/cm2G 程度で運転する。
One of the important points of the present invention resides in that the cyclic dimer in the aqueous solution obtained as described above is ring-opened by 15% or more. The conditions for ring opening are not particularly limited, but ring opening is preferably performed in the enrichment step described below.
Any well-known concentration method such as a multistage concentration method can be applied to the concentration of the extracted oligomer aqueous solution, but the concentration is usually 70 to 98% by weight, preferably 75 to 95% by weight as the oligomer concentration. The operation is performed at a pressure of 10 to 30 kg / cm 2 G, preferably about 10 to 20 kg / cm 2 G.
環状ダイマーを鎖状体に開環させるには、水分圧で１０kg/cm2G 以上の圧力に到達させる必要があり、温度と対応する濃縮度に到達させる必要がある。例えば２３０℃で、１６．５kg/cm2G では濃度８０重量％、１０kg/cm2G では９１重量％となる。環状ダイマーを鎖状体に開環させる条件として、水分圧１０kg/cm2G 以上及び温度２３０℃以上、好ましくは水分圧１３kg/cm2G 以上及び温度２４０℃以上、より好ましくは水分圧１５kg/cm2G 以上及び温度２５０℃以上に到達させ、その後通常０．１〜１０時間、好ましくは０．５〜５時間その状態に保持する。この圧力及び温度が低すぎると環状ダイマーは全く開環しないで回収され、一定の割合で環状ダイマーが増え続け、環状ダイマーを多く含有する不良な製品となる。環状ダイマーの開環には圧力及び温度とも高い場合には不都合はないが、ポリアミド樹脂の分解速度が急に増す３００℃以上や、リサイクルする重合反応系内の水分量が極端に多くなる水分圧（３０kg/cm2G 以上）は好ましくない。
一方カプロラクタム及び環状ダイマー以外の環状オリゴマーは、鎖状体とする条件として上記のような高温、高圧まで必要としない。
In order to open the cyclic dimer into a chain, it is necessary to reach a pressure of 10 kg / cm 2 G or more by water pressure, and to reach a concentration corresponding to the temperature. For example at 230 ° C., a 16.5 kg / cm 2 G at concentration of 80 wt%, 10kg / cm 2 91 wt% in G. Conditions for opening the cyclic dimer into a chain include water pressure of 10 kg / cm 2 G or higher and a temperature of 230 ° C. or higher, preferably a water pressure of 13 kg / cm 2 G or higher and a temperature of 240 ° C. or higher, more preferably 15 kg / cm 2 or more. cm 2 G or more and a temperature of 250 ° C. or more, and then kept in that state for usually 0.1 to 10 hours, preferably 0.5 to 5 hours. If the pressure and temperature are too low, the cyclic dimer is recovered without ring opening at all, and the cyclic dimer continues to increase at a certain rate, resulting in a defective product containing a large amount of cyclic dimer. There is no inconvenience when the pressure and temperature are high for the ring opening of the cyclic dimer, but the decomposition pressure of the polyamide resin rapidly increases at 300 ° C or higher, or the water pressure at which the amount of water in the polymerization reaction system to be recycled becomes extremely large. (30 kg / cm 2 G or more) is not preferable.
On the other hand, the cyclic oligomers other than caprolactam and cyclic dimer do not require the high temperature and high pressure as described above as a condition for forming a chain.
本発明では所定の圧力及び温度に到達させるまでの方法に特に制限はないが、圧力が一定値に保持された状態で所定の温度まで昇温することによって、水分圧を所定圧力に到達させる方法が好ましい。このとき、他の不活性ガス等が存在していてもよい。 In the present invention, there is no particular limitation on a method for reaching a predetermined pressure and temperature, but a method for raising the water pressure to a predetermined pressure by raising the temperature to a predetermined temperature while maintaining the pressure at a constant value. Is preferred. At this time, another inert gas or the like may be present.
本発明において特に問題とする環状ダイマーは、この所定の水分圧・温度に到達させるまでにある程度開環するが、この水分圧・温度に到達させないと環状ダイマーの開環は十分ではなく、リサイクル回数が増すにつれ、製品中のダイマー量が増加する。
したがって、ポリアミド樹脂を抽出して得られる水溶液中環状オリゴマーのうち、環状ダイマーを１５％以上開環、鎖状体とした後、重合反応器に供給し、回収する。好ましくは２５％以上、更に好ましくは３５％以上まで開環させた後回収する。
The cyclic dimer, which is a particular problem in the present invention, opens to some extent before reaching the predetermined water pressure / temperature. However, if the water pressure / temperature is not reached, ring opening of the cyclic dimer is not sufficient, and As the amount of dimer increases, the amount of dimer in the product increases.
Therefore, among the cyclic oligomers in the aqueous solution obtained by extracting the polyamide resin, the cyclic dimer is ring-opened by 15% or more to form a chain, and then supplied to the polymerization reactor and collected. Preferably, the ring is opened to 25% or more, more preferably 35% or more, and then recovered.
本発明においては、上記の工程で得られた濃縮オリゴマーを溶融状態のままで重合反応器に供給する。濃縮オリゴマーを冷却固化させて重合反応器に供給すると、容易に溶解せず、製品中に残存してフィッシュアイを生成するとか、装置の閉塞を招く等の不都合がある。 に お い て In the present invention, the concentrated oligomer obtained in the above step is supplied to the polymerization reactor in a molten state. When the concentrated oligomer is cooled and solidified and supplied to the polymerization reactor, it does not easily dissolve and remains in the product to form fish eyes, or causes inconvenience such as blockage of the apparatus.
また、本発明の方法においては、オリゴマーが高温度に長時間保持される機会が多く、微量の酸素によっても着色等の不都合を招きやすいので、抽出オリゴマー水溶液の濃縮、貯蔵、転送等に当って、特に酸素の洩れ込みがないよう厳重に管理することが望ましい。 Further, in the method of the present invention, the oligomer is often held at a high temperature for a long time, and even a trace amount of oxygen easily causes inconvenience such as coloring. In particular, it is desirable to strictly control oxygen leakage.
重合方法は、水を存在させて加圧下カプロラクタムを加水分解して開環させ、次いで放圧して水分を除去し、常圧ないし減圧下で重縮合させる周知の方法が適用できる。当然この環境下でも環状ダイマーのうち一部は開環されるが、これだけでは、製品として問題のない環状ダイマー量まで低減するのに不十分であるため、上記のように抽出液として独立して厳しい環境（高温、高圧）を設定している。 As a polymerization method, a well-known method of hydrolyzing caprolactam under pressure in the presence of water to open the ring, then removing the water by releasing the pressure, and performing polycondensation under normal pressure or reduced pressure can be applied. Naturally, even in this environment, a part of the cyclic dimer is opened, but this alone is insufficient to reduce the amount of the cyclic dimer that is not problematic as a product. Severe environment (high temperature, high pressure) is set.
重合反応器への新しいカプロラクタムの供給量は、濃縮オリゴマーと新しいカプロラクタムからなる混合物中の水分含有量が、全カプロラクタムとその低重合体の全量に対して０．５〜１０重量％、好ましくは１〜４重量％、より好ましくは１．３〜２．５重量％の範囲内となるようにするが、本発明の特定水分含有量の濃縮オリゴマーを使用すれば、前記特公昭４０−１５６６３号公報の方法のように多量の新しいカプロラクタムを追加することなく、上記の所要水分条件を満足することができるので工業的に有利である。 The amount of fresh caprolactam supplied to the polymerization reactor is such that the water content in the mixture of concentrated oligomer and fresh caprolactam is 0.5 to 10% by weight, preferably 1 to 10% by weight, based on the total amount of caprolactam and its low polymer. -4 wt%, more preferably 1.3-2.5 wt%. However, if the concentrated oligomer having a specific water content of the present invention is used, the above-mentioned Japanese Patent Publication No. 40-15663 can be used. This method is industrially advantageous because the above-mentioned required water condition can be satisfied without adding a large amount of new caprolactam as in the method (1).
重合反応器内での圧力、温度条件により、環状オリゴマーの開環の程度は当然異なり、通常の重合条件下では回収量の３割弱程度を開環させることができるが、残りの７割の可能な限り多い量を開環させ、得られる製品を成形する際環状ダイマーの昇華による不都合が生じない程度まで低減することが、本発明によって改善された点である。 The degree of ring opening of the cyclic oligomer naturally varies depending on the pressure and temperature conditions in the polymerization reactor. Under ordinary polymerization conditions, about 30% of the recovered amount can be opened, but the remaining 70% can be opened. It is an improvement of the present invention to open as much of the ring as possible and reduce it to the extent that inconvenience due to sublimation of the cyclic dimer does not occur when shaping the resulting product.
以下、本発明を実施例を挙げて具体的に説明するが、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.
実施例１
ε−カプロラクタムに水２．５重量％を添加し、オートクレーブ中で２８５℃に加熱した後、缶内圧６kg/cm2G を徐々に減圧し、更に表１に示した減圧度にて、２時間反応させた後、樹脂をストランドとして抜き出し、チップ化して未抽出ペレットを得た。同ペレットを水で向流抽出し、有機物濃度８重量％の水溶液を得ると同時に、抽出ペレットを得た。抽出した未反応カプロラクタム及びオリゴマーの総量は未抽出ペレット中９重量％であった。この抽出液中の有機物を圧力１６kg/cm2G の一定圧で、２７０℃まで加熱して９４重量％に濃縮した（このときの水分圧１６kg/cm2G)後、この状態を２時間保持した。
このようにして得られた鎖状オリゴマーを新たなカプロラクタム中へ投入し、総重量を１回目と同一にして、上記と同一の操作を繰返しペレットを得た。
このような操作を５回繰返し、最後に得た製品中の環状ダイマー量を確認した結果、最初の１回目に得た製品（リサイクルなし）と変わらず、良好なナイロン６が得られていることが分かった。結果を表１に示す。
Example 1
After adding 2.5% by weight of water to ε-caprolactam and heating to 285 ° C. in an autoclave, the internal pressure of the vessel was gradually reduced to 6 kg / cm 2 G, and further at the reduced pressure shown in Table 1 for 2 hours. After the reaction, the resin was drawn out as a strand and chipped to obtain an unextracted pellet. The pellet was countercurrently extracted with water to obtain an aqueous solution having an organic substance concentration of 8% by weight, and at the same time, an extracted pellet was obtained. The total amount of unreacted caprolactam and oligomer extracted was 9% by weight in the unextracted pellet. The organic matter in this extract was heated to 270 ° C. at a constant pressure of 16 kg / cm 2 G and concentrated to 94% by weight (at this time, the water pressure was 16 kg / cm 2 G), and this state was maintained for 2 hours. did.
The chain oligomer thus obtained was charged into a new caprolactam, the total weight was made the same as the first time, and the same operation as above was repeated to obtain a pellet.
This operation was repeated five times, and the amount of cyclic dimer in the product obtained last was confirmed. As a result, good nylon 6 was obtained as in the first product obtained (no recycling). I understood. Table 1 shows the results.
なお、オリゴマーの分析法は下記のとおりであり、また得られたポリアミド樹脂の相対粘度（ηrel)の測定はＪＩＳ Ｋ６８１０に準拠した。
オリゴマー分析法：水溶液中のカプロラクタム及び環状オリゴマーは、Ｈ2 Ｏ／メタノールを溶離液に、２１０nmＵＶにて直接液体クロマトグラフ分析（ＬＣ）することにより分離、定量した。一方、ペレット中に包含されたカプロラクタム及び環状オリゴマーは、メタノールを溶剤として沸騰抽出した後、同液をＬＣ分析することで分離、定量した。
The method for analyzing the oligomer was as follows, and the relative viscosity (η rel ) of the obtained polyamide resin was measured in accordance with JIS K6810.
Oligomer analysis: Caprolactam and cyclic oligomer in the aqueous solution were separated and quantified by direct liquid chromatography analysis (LC) at 210 nm UV using H 2 O / methanol as an eluent. On the other hand, the caprolactam and the cyclic oligomer contained in the pellet were separated and quantified by subjecting the solution to boiling extraction using methanol as a solvent and then performing LC analysis on the same solution.
実施例２
抽出液中の有機物を９３重量％に濃縮した以外は、実施例１と同様に実施した。結果を表１に示す。
Example 2
The procedure was performed in the same manner as in Example 1 except that the organic matter in the extract was concentrated to 93% by weight. Table 1 shows the results.
実施例３
抽出液中の有機物を圧力１６kg/cm2G で２４０℃まで加熱して９０重量％に濃縮した（このときの水分圧１６kg/cm2G)以外は、実施例１と同様に実施した。結果を表１に示す。
Example 3
The operation was performed in the same manner as in Example 1 except that the organic matter in the extract was heated to 240 ° C. at a pressure of 16 kg / cm 2 G and concentrated to 90% by weight (at this time, the water pressure was 16 kg / cm 2 G). Table 1 shows the results.
比較例１
抽出液を圧力１０kg/cm2G 、２２０℃まで加熱して８５重量％に濃縮した（このときの水分圧１０kg/cm2G)以外は、実施例１と同様に実施した。結果を表１に示す。
Comparative Example 1
The extraction was carried out in the same manner as in Example 1 except that the extract was heated to 220 ° C. under a pressure of 10 kg / cm 2 G and concentrated to 85% by weight (water pressure at this time was 10 kg / cm 2 G). Table 1 shows the results.
実施例４
ε−カプロラクタム８５重量部とアジピン酸−ヘキサメチレンジアミンの塩１５重量部とを共重合して得た未抽出ペレットを水で向流抽出し、有機物濃度７重量％の水溶液を得ると同時に抽出ペレットを得た。抽出した未反応カプロラクタム及びオリゴマーの総量は、未抽出ペレット中７．５重量％であった。この抽出液中の有機物を圧力１６kg/cm2G の一定圧で、２４０℃まで加熱して９０重量％まで濃縮した（このときの水分圧１６kg/cm2G)後、２時間保持した。実施例１と同様にこの操作を５回繰返した。結果を表１に示す。
Example 4
Unextracted pellets obtained by copolymerizing 85 parts by weight of ε-caprolactam and 15 parts by weight of adipic acid-hexamethylenediamine are countercurrently extracted with water to obtain an aqueous solution having an organic substance concentration of 7% by weight and at the same time extract the pellets. Got. The total amount of unreacted caprolactam and oligomers extracted was 7.5% by weight in the unextracted pellets. The organic matter in the extract was heated to 240 ° C. at a constant pressure of 16 kg / cm 2 G to concentrate it to 90% by weight (at this time, the water pressure was 16 kg / cm 2 G), and then kept for 2 hours. This operation was repeated five times as in Example 1. Table 1 shows the results.
比較例２
実施例４において、抽出液を圧力１０kg/cm2G の一定圧で、２２０℃まで加熱して８５重量％に濃縮した（このときの水分圧１０kg/cm2G)以外は、実施例１と同様に実施した。結果を表１に示す。
Comparative Example 2
Example 4 was repeated except that the extract was heated to 220 ° C. at a constant pressure of 10 kg / cm 2 G and concentrated to 85% by weight (at this time, the water pressure was 10 kg / cm 2 G). The same was performed. Table 1 shows the results.
実施例１及び比較例１での抽出された環状オリゴマーの組成を表２に示した。表２より、環状ダイマーが最も蓄積されやすく、他の環状オリゴマーはリサイクルしても大きな変化のないことが分かる。 Table 2 shows the composition of the extracted cyclic oligomer in Example 1 and Comparative Example 1. From Table 2, it can be seen that the cyclic dimer is most likely to accumulate, and that the other cyclic oligomers do not change significantly when recycled.
［発明の効果］
本発明の方法に従って、カプロラクタムよりポリアミド樹脂を製造する場合、得られるポリアミド樹脂は高品質でカプロラクタム単体から製造したものと全く遜色ない。しかも、同ポリアミド樹脂から抽出されたオリゴマーは、全量その重合反応系に再使用することができ、高い歩留りが達成できるので工業的に極めて有利である。
[The invention's effect]
When a polyamide resin is produced from caprolactam according to the method of the present invention, the polyamide resin obtained is of high quality and is comparable to that produced from caprolactam alone. In addition, the entire amount of the oligomer extracted from the polyamide resin can be reused in the polymerization reaction system, and a high yield can be achieved, which is industrially extremely advantageous.
Claims (2)
（１）前記水溶液中の環状オリゴマーのうち、環状ダイマーを１５％以上開環させて鎖状体とした濃縮オリゴマーを溶融状態のままで、重合反応器に供給し、次いで
（２）前記追加量のカプロラクタムを添加する、
ことを繰り返すことを特徴とするカプロラクタムよりポリアミド樹脂を製造する方法。 A polyamide resin obtained by polymerizing caprolactam in the presence of water is extracted with water, and the obtained aqueous solution containing unreacted caprolactam and its low polymer is concentrated to 70 to 98% by weight and added to the concentrate. A method for producing a polyamide resin to be polymerized by adding an amount of caprolactam,
(1) Among the cyclic oligomers in the aqueous solution, a concentrated oligomer in which a cyclic dimer is ring-opened by 15% or more to form a chain is supplied to a polymerization reactor in a molten state, and then (2) the additional amount Add caprolactam,
A process for producing a polyamide resin from caprolactam.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2003346527A JP2004010902A (en) | 1995-11-06 | 2003-10-06 | Method for producing polyamide resin from caprolactam |
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| JP2003346527A JP2004010902A (en) | 1995-11-06 | 2003-10-06 | Method for producing polyamide resin from caprolactam |
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| JP8262917A Division JPH09188758A (en) | 1995-11-06 | 1996-10-03 | Production of polyamide resin from caprolatam |
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| JP2007026011A Division JP4755611B2 (en) | 1995-11-06 | 2007-02-05 | Method for producing polyamide resin from caprolactam |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007113020A (en) * | 1995-11-06 | 2007-05-10 | Mitsubishi Chemicals Corp | Method for production of polyamide resin from caprolactam |
| EA017493B1 (en) * | 2008-08-19 | 2012-12-28 | Лурги Циммер Гмбх | Continuous method for extracting monomer caprolactam |
| WO2017104444A1 (en) * | 2015-12-17 | 2017-06-22 | 日本合成化学工業株式会社 | Resin composition and method for producing same |
-
2003
- 2003-10-06 JP JP2003346527A patent/JP2004010902A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007113020A (en) * | 1995-11-06 | 2007-05-10 | Mitsubishi Chemicals Corp | Method for production of polyamide resin from caprolactam |
| EA017493B1 (en) * | 2008-08-19 | 2012-12-28 | Лурги Циммер Гмбх | Continuous method for extracting monomer caprolactam |
| WO2017104444A1 (en) * | 2015-12-17 | 2017-06-22 | 日本合成化学工業株式会社 | Resin composition and method for producing same |
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