JP3662805B2 - Continuous kneading method and apparatus for polyester resin - Google Patents

Description

【００３１】
この〔表１〕から明らかなように、Ｌ１／Ｄが１２である実験番号３の場合には、ＩＶ値が０．６０に低下している。これは、原料樹脂の当初含有水分が乾燥区間１４において十分に除去されず、更に増粘処理に伴い発生する反応生成物に架橋反応が阻害されたからであると考えられる。
また、Ｌ２／Ｄが４０である実験番号５の場合にも、ＩＶ値が０．６８に低下している。これは、増粘区間１５が長すぎて増粘処理中にＰＥＴ樹脂の劣化が起こったためであると考えられる。
【００３２】
更に、実験番号２，４及び５を比較すれば分かるように、Ｌ２／Ｄが３０までの間では、増粘区間１５を長くすればするほどＩＶ値が向上する。
また、実験番号３〜６については低ＩＶ値の繊維紡糸が、実験番号７〜９については高ＩＶ値の繊維紡糸が、それぞれ可能であったことを示している。
更に、ジフェニルメタン−４，４−ジイソシアネートを使用した実験番号７〜９の場合、他の薬剤を添加して練った樹脂に比べて分子量分布（Ｍｗ／Ｍｎ）がかなり小さくなっていることから、鎖長の揃った良質なポリマーが得られることが判る。
【００３３】
図２は、本発明の第二の実施形態を示している。
本実施形態の連続混練装置１は、原料樹脂を予め乾燥機にかけてから増粘処理するタイプの二軸連続混練装置であり、材料供給口２と材料排出口３を有するチャンバ４と、このチャンバ４内に回転自在に挿通された左右一対の混練ロータ（図示せず）と、を備えている。
チャンバ４の材料供給口２には、後述する材料供給手段２１と、原料樹脂の粘度を増加させるか又はその低下を抑制する薬剤をチャンバ４内に添加するためのスクリューフィーダ等よりなる薬剤供給手段１０が接続され、チャンバ４の下流側端に位置する材料排出口３には、ペレタイザやダイス等よりなる後処理装置１１がギアポンプや単軸押出機等の増圧手段を介して接続されている。
【００３４】
本実施形態では、材料供給手段２１は、原料樹脂から水分を除去する乾燥機２２と、この乾燥機２２の下端に直結されかつ乾燥された原料樹脂を防湿状態で貯溜する貯溜ホッパ２３と、乾燥機２２と貯溜ホッパ２３との間に介在された開閉自在なシャッター手段２４と、を備えている。
このシャッター手段２４は、乾燥機２２と貯溜ホッパ２３の接続開口部に水平移動自在に挿通された閉鎖板と、この閉鎖板を開閉させる油圧シリンダ等よりなるアクチュエータと、を備えている。
【００３５】
乾燥機２２の上端には、開閉弁２５を有する供給ホッパ２６が接続され、同乾燥機２２に内部には、原料樹脂を攪拌するための攪拌羽根２７が回転自在に設けられている。この乾燥機２２の上下端部には熱風の給排口２８が設けられ、この給排口２８から約１６０°Ｃの熱風を給排することにより、乾燥機２２内の原料樹脂が乾燥される。
なお、この乾燥機２２は水分量が５０ｐｐｍ以下となるように原料樹脂を乾燥させる機能を有するものであればよく、熱風を循環させて乾燥する以外にも、給排口２８から除湿された不活性ガスを循環させて乾燥するようにしてもよい。
【００３６】
貯溜ホッパ２３の下端開口にはスクリューフィーダ等よりなる定量供給手段２９が接続され、この供給手段２９の吐出口はチャンバ４の材料供給口２に接続されている。
本実施形態の連続混練装置１を使用するには、再生ＰＥＴフレーク等よりなる原料樹脂を所定量だけ供給ホッパ２６に供給し、シャッター手段２４を閉鎖した状態で開閉弁２５開いてその原料樹脂を乾燥機２２に供給する。
その後、熱風乾燥が終了した時点でシャッター手段２４を開放して所定量の乾燥樹脂を貯溜ホッパ２３に供給し、同樹脂を定量供給手段２９でチャンバ４内に押し込んで増粘処理を行う。
【００３７】
そして、この増粘処理が行われている間に、次の所定量の原料樹脂を供給ホッパ２６から乾燥機２２に供給して乾燥処理を行っておき、前の所定量の原料樹脂の増粘処理が終わる直前に乾燥が終了した所定量の原料樹脂を貯溜ホッパ２３に供給する。
なお、本実施形態では、乾燥機２２における乾燥処理量とチャンバ４内における増粘処理量とがほぼ等量となるように、混練ロータの回転数と熱風の給排量が設定されている。
【００３８】
このように、本実施形態によれば、貯溜ホッパ２３内の始めの所定量の原料樹脂が増粘処理されている間に次の所定量の原料材料を乾燥できるので、原料樹脂を予め乾燥機２２にかけてから増粘処理する場合において、原料樹脂の乾燥工程と増粘工程を連続的に行うことができる。
また、本実施形態では、チャンバ４とは別体の乾燥機２２で原料樹脂を予めプレ乾燥しているため、第一実施形態の場合ほどチャンバ４のＬ／Ｄ値を長くする必要がなく、通常採用されているＬ／Ｄの範囲内の混練機を採用することができる。
【００３９】
なお、本実施形態においても、増粘処理の際に生じる反応生成物を排出すべく、チャンバ４のベント口に真空ポンプを接続することにしてもよい。
また、薬剤添加手段１０は、原料樹脂を乾燥し終えている（具体的には、水分量が５０ｐｐｍ以下）ところから薬剤を供給できるのであれば、チャンバ４以外の部分（例えば、貯溜ホッパ２３）に接続することもできる。
図３は、第二の実施形態（図２）の変形例を示しており、この場合の連続混練装置１は、混練押出機として単軸混練押出機３０を採用している。このため、この変形例では、原料材料を強制的に送り込むための定量供給装置２９が設けられていないが、必要があれば適宜設けても構わない。
【００４０】
図４は、第一の実施形態（図１）の変形例を示しており、この場合の連続混練装置１は、混練ロータ５における薬剤供給手段１０の上下流側の近傍に、フィード部１７とは逆向きのスクリュー形状を有するリバースフライト２５，２６よりなる樹脂充満手段を設けている点で、第一の実施形態の場合と異なる。
すなわち、図４に示す変形例装置では、薬剤供給手段１０よりも上流側でかつ乾燥区間１４内の最下流側ベント口７Ｃよりも下流側と、薬剤供給手段１０よりも下流側でかつ増粘区間１５内の最上流側ベント口７Ｄよりも上流側にそれぞれリバースフライト２５，２６を配置し、これにより、チャンバ４内における薬剤供給手段１０の直前及び直後の空間を溶融樹脂で充満させながら、原料樹脂を混練するようにしている。
【００４１】
このため、薬剤供給手段１０から添加された薬剤が乾燥区間１４や増粘区間１５に飛散し、各ベント口７Ａ〜７Ｅから吸引されて消失するのが有効に防止されることになるので、原料樹脂中に無駄なく薬剤を混ぜ込むことができ、定量的かつ安定的な薬剤供給を行うことができる。
また、リバースフライト２５，２６にって乾燥区間１４と増粘区間１５がきっちりと仕切られているので、それらの区間１４，１５内を互いに独立して適切な真空度に設定することができる。
【００４２】
なお、チャンバ４内の空間を樹脂で充満させるための部材（樹脂充満手段）としては、上記リバースフライト２５，２６の他に、混練ロータ５に設けたニーディングディスクやシールリングを採用することができる。
また、かかる樹脂充満手段は、薬剤供給手段１０の上流側だけに設けることにしてもよい。
更に、薬剤供給手段１０の上流側に設ける樹脂充満手段の場合には、混練ロータ５に設けた断面円形部と、この断面円形部に対向してチャンバ内の樹脂に絞りをかける対向縁を有する固定式又は可動式の上下一対のゲート部材と、を有するゲート装置（例えば、特公昭５８−５０５３３号公報参照）を採用することもできる。
【００４３】
特に、上記ゲート装置の場合には、上下のゲート部材の断面円形部に対する間隙量を変化させることにより樹脂の充満度を意図的に調節できるので、乾燥区間１４での混練時間（乾燥時間）を調節するのが容易になるという利点がある。
なお、以上説明した本発明により処理できるポリエステル系樹脂としては、未使用のポリエステル系樹脂、及び再生されたポリエステル系樹脂の双方を対象とする。
ポリエステルの構成成分としては、脂肪族、環状脂肪族又は芳香族のジカルボン酸及びジオール、又はヒドロキシカルボン酸から誘導されるホモポリエステル、又はコポリエステル（共重合体）等が挙げられる。
【００４４】
上述の脂肪族カルボン酸として適当な例を挙げると、スベリン酸、シュウ酸、マロン酸、ジメチルマロン酸、コハク酸、ピメリン酸、アジピン酸、セバシン酸、アゼライン酸、ダイマー酸等である。
また、適当な環状脂肪族ジカルボン酸として、１，３−シクロブタンジカルボン酸、１，３−シクロペンタンジカルボン酸、１，３−及び１，４−シクロヘキサンジカルボン酸、１，３−及び１，４−（ジカルボキシメチル）シクロヘキサン、４，４−ジシクロヘキシルジカルボン酸等が挙げられる。
【００４５】
また、適当な芳香族ジカルボン酸として、テレフタル酸、イソフタル酸、ｏ−フタル酸、１，３−、１．４−、２，６−又は２，７−ナフタレンジカルボン酸、４，４−ジフェニルジカルボン酸、４，４−ベンゾフェノンジカルボン酸、４，４−ジフェニルエーテルジカルボン酸等が挙げられる。
ジカルボン酸としては、芳香族ジカルボン酸が好ましく、特にテレフタル酸及びイソフタル酸が好ましい。
適当な脂肪族ジオールとして、エチレングリコール、１，２−及び１，３−プロピレングリコール、１，２−、１，３−、２，３−又は１，４−ブタンジオール、ペンチルグリコール、ネオペンチルグリコール、１，６−ヘキサンジオール、１，１２−ドデカンジオール、ジエチレングリコール等が挙げられる。
【００４６】
また、適当な環状脂肪族ジオールとして、１，４−ジヒドロキシシクロヘキサン、１，４−ビス（ヒドロキシメチル）シクロヘキサン等が挙げられる。
適当な芳香族−脂肪族ジオールとして、ｐ−キシレングリコール、２，５−ジクロロ−ｐ−キシレングリコール、２，２−（β−ヒドロキシエトキシフェニル）プロパン等が挙げられる。
ジオールとしては、アルキレングリコール、１，４−ジヒドロキシシクロヘキサン及び１，４−ビス（ヒドロキシメチル）シクロヘキサンが好ましく、特にエチレングリコール及び１，４−ブタンジオールが好ましい。
【００４７】
添加剤として用いる鎖延長剤とは、ポリエステル末端のＯＨ基、ＣＯＯＨ基と反応し、分子鎖を延長させるものを総称するものである。
鎖延長剤としては、例えば、芳香族テトラカルボン酸二無水物として、ピロメリット酸二無水物、２，２−ビス（３，４−ジカルボキシフェニル）プロパン二無水物、３，３’、４，４’−ベンゾフェノンテトラカルボン酸二無水物、３，３’、４，４’−ビフェニルテトラカルボン酸二無水物、オキシジフタル酸二無水物、ビス（３，４−ジカルボキシフェニル）エーテル二無水物、（ジフェニルテトラカルボキシル）スルホン二無水物等が挙げられる。
【００４８】
また、脂肪族テトラカルボン酸二無水物として、シクロブタン１，２，３，４−テトラカルボン酸二無水物、シクロペンタンテトラカルボン酸二無水物、テトラヒドロフランテトラカルボン酸二無水物等が挙げられる。なお、テトラカルボン酸二無水物としては、芳香族の方が好ましい。
ジエポキシ化合物として、ジグリシジルテレフタレート、ビスフェノールＡジグリシジルエーテル等が挙げられる。また、イソシアネート化合物として、ジフェニルメタン−４，４’−ジイソシアネート、１−メチルベンゼン−２，４−ジイソシアネート、ヘキサン−１，６−ジイソシアネート等が挙げられる。
【００４９】
上記鎖延長剤は単独での使用に限らず、反応を促進させる触媒と併用することができる。例えば、ジエポキシ化合物とイミダゾール化合物とを併用することができる。
添加剤として用いる重合触媒とは、脱エチレングリコールにより、ポリエステルの繰り返し単位を延長するものである。重合触媒としては、例えば三酸化アンチモン、二酸化ゲルマニウム等が挙げられる。
なお、鎖延長剤と重合触媒は、粘度を向上ないしその低下を抑制する薬剤として、これらの両方を用いても構わないし、一方のみであっても構わない。また、その配合量は、原料樹脂の種類や処理時間等の様々な要因に合わせて適宜調節することができる。
【００５０】
鎖延長剤は、上記したものが特に制限なく利用可能であるが、ジフェニルメタン４，４−ジイソシアネートを使用した場合、極限粘度が高く、鎖長の揃った（つまり、分子量分布Ｍｗ／Ｍｎが小さい）ポリマーが得られ、特に好ましい。
【００５１】
【発明の効果】
以上説明したように、本発明によれば、一連のチャンバ内において、増粘作用のある薬剤を添加せずに原料樹脂をいったん減圧脱水しながら混練したたあと、同薬剤を原料樹脂に添加して更に原料樹脂を減圧脱揮しながら混練するようにしたので、原料樹脂を予め乾燥機にかけないで増粘処理する場合において、その増粘効果をより高めることができる。
また、本発明によれば、原料樹脂を予め乾燥機にかけてから増粘処理する場合において、原料樹脂の乾燥工程と増粘工程を連続的に行えるので、原料樹脂の貯蔵コストを低減することができる。
【図面の簡単な説明】
【図１】本発明の第一の実施形態に係る連続混練装置の概略図である。
【図２】本発明の第二の実施形態に係る連続混練装置の概略図である。
【図３】本発明の第二の実施形態の変形例に係る連続混練装置の概略図である。
【図４】本発明の第一の実施形態の変形例に係る連続混練装置の概略図である。
【符号の説明】
１ 連続混練装置
２ 材料供給口
３ 材料排出口
４ チャンバ
５ 混練ロータ
６ 材料供給手段
７ ベント口
８ 第一真空ポンプ
９ 第二真空ポンプ
１４ 乾燥区間
１０ 薬剤供給手段
１５ 増粘区間
１６ 混練部
２１ 材料供給手段
２２ 乾燥機
２３ 貯溜ホッパ
２４ シャッター手段
２５ リバースフライト（樹脂充満手段）
２６ リバースフライト（樹脂充満手段）
Ｌ１ 乾燥区間の軸方向長さ
Ｌ２ 増粘区間の軸方向長さ
Ｄ チャンバの内径[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a continuous kneading method and a continuous kneading apparatus for polyester resins.
[0002]
[Prior art]
Polyester resins are used in various applications because of their excellent mechanical properties such as tensile strength and impact resistance, as well as excellent heat resistance and weather resistance. In particular, polyethylene terephthalate resin (PET resin) has the above properties. It is excellent and is lighter than glass, so it is widely used for food containers.
In order to obtain a high-quality processed PET resin product, it is necessary that the PET resin has good moldability and physical properties. For this purpose, an intrinsic viscosity value (IV value) of a certain level or more is required. In particular, since the recycled PET resin once used and recovered has a large IV value due to heat applied at the time of molding, the PET resin is also efficient from the viewpoint of improving the quality of the recycled PET resin product. There is a demand for a method of increasing the viscosity.
[0003]
However, on the other hand, since the IV value is lowered by moisture generated by hydrolysis when the polyester resin is melted, the polyester resin has a property of causing a reduction in molding characteristics of the resin product thereafter.
Therefore, a chamber having a material supply port and a material discharge port, a kneading rotor rotatably inserted into the chamber, a vacuum pump for dehydrating the inside of the chamber, and a material supply means connected to the material supply port A polyester resin continuous kneading apparatus has been developed comprising a chemical supply means connected to the chamber for adding a chemical (crosslinking agent) that increases or decreases the viscosity of the raw material resin into the chamber. ing.
[0004]
According to this continuous kneading apparatus, the polyester resin added with the crosslinking agent is kneaded while dehydrating under reduced pressure in the chamber, thereby preventing a decrease in IV value without drying the resin in advance. (See JP-A-8-183083).
[0005]
[Problems to be solved by the invention]
However, in the above conventional technique, since the crosslinking agent is suddenly added from the stage before dehydration under reduced pressure from the vent port, that is, before the raw material resin starts to melt, the crosslinking reaction and hydrolysis of the raw material resin are performed at the time of melting. The reaction will occur simultaneously.
For this reason, the molecular weight is lowered in the hydrolysis reaction accompanying the melting of the raw resin due to the moisture contained in the raw resin from the beginning, and there is a disadvantage that the increase in the IV value due to the crosslinking reaction is reduced.
[0006]
In this case, the amount of the crosslinking agent added may be increased in consideration of the moisture contained in the raw material resin from the beginning. Especially in the case of recycled PET flakes, the moisture content may be as high as several thousand ppm. Therefore, a means for improving the thickening effect only by increasing the addition amount requires a large amount of a crosslinking agent, which is uneconomical.
In view of such circumstances, a first object of the present invention is to make it possible to further increase the thickening effect in the case where the raw material resin is thickened without being previously dried.
[0007]
On the other hand, in the case of a PET resin, if the raw material resin is dried in advance until the water content becomes 50 ppm or less, then the dianhydride of aromatic tetracarboxylic acid is added and kneaded and melted, so that a low-viscosity recycled PET resin is obtained. Further, it is known that even an extraordinary PET resin can be effectively used as a foam molded product (see, for example, JP-A-8-231750).
However, in order to dry the raw material resin in advance until the moisture content is reached, usually a large-scale batch-type dryer is required, which increases the equipment cost exclusively. Since it cannot be processed continuously, it is necessary to store a large amount of the dried raw material resin, and there is a disadvantage that the storage cost is increased.
[0008]
In view of such circumstances, the present invention allows the raw resin to be dried and thickened in advance when the raw resin is subjected to a drying process in advance, thereby reducing the storage cost of the raw resin. The second purpose is to reduce it.
[0009]
[Means for Solving the Problems]
In order to achieve the first object, the present invention takes the following technical means.
That is, the first apparatus according to the present invention is a drying section in which the portion upstream of the chemical supply means in the chamber is kneaded while dehydrating the raw material resin before adding the chemical in the continuous kneading apparatus for polyester resin. The portion on the downstream side of the medicine supply means is a thickening section in which the raw material resin after the addition of the medicine is kneaded while being devolatilized under reduced pressure.
[0010]
In this case, in one chamber continuous in the axial direction, after the raw material resin not containing the agent (thickening agent) that increases the viscosity of the raw material resin or suppresses the decrease in viscosity is once kneaded while being dehydrated under reduced pressure in the drying section, Since the raw material resin containing the same agent is kneaded while being further devolatilized under reduced pressure in the thickening section, most of the water contained in the raw material resin is removed together with the water accompanying hydrolysis after melting in the drying section. Become.
Thus, since the said chemical | medical agent is added in a thickening area after removing the water | moisture content which raw material resin contains from the beginning in a drying area, it is prevented that a thickening reaction is inhibited with the initial moisture, and a thickening reaction is carried out. As a result, the amount of increase in the IV value can be improved as compared with the conventional method, and the amount of the drug added can be suppressed to a small amount.
[0011]
More specifically, in the above first invention apparatus, when the inner diameter of the chamber is D, the axial length of the drying section is L1, and the axial length of the thickening section is L2, L1 / D is The axial length of the chamber is set so that it is 15 or more and 25 or less, and L2 / D is 15 or more and 30 or less.
That is, L1 / D of the drying section is set to the above range as a length necessary and sufficient to dry the raw material resin having a large variation in moisture content. For example, in the case of PET resin, it is known that a thickening reaction occurs sufficiently if the water content falls to around 50 ppm, but in order to reduce the water content so far, L1 / D is set to 15 or more. Can be achieved by taking sufficient residence time.
[0012]
On the other hand, if the water content falls to around 50 ppm, no further dehydration effect can be expected even if the drying section is lengthened, and impurities such as water and ethylene glycol accompanying melting during the thickening reaction are not Since it is devolatilized under reduced pressure in the thickening section, 25 or less is sufficient for L1 / D in the drying section. In addition, a predetermined residence time is required to improve the IV value of the polyester-based resin, and the longer the thickening section, the longer the residence time and the greater the amount of resin that can be processed. Due to the above relationship, the thickening section cannot be extended unnecessarily. Furthermore, it has been found from various experimental results that the residence time in the thickening section is required to be at least about 2 minutes in order to obtain a sufficient thickening reaction. The value was set in the above range.
[0013]
And in order to make the residence time of the material to be kneaded in the thickening section be 2 minutes or more, it can be achieved by providing a kneading part having a staying function in the portion of the kneading rotor located in the thickening section. Specifically, this kneading part can be composed of a rotor segment having a feed blade and a return blade or a kneading block having a reverse flight.
When such a kneading part is employed, a sufficient residence time can be obtained with a short L / D, which is preferable because the equipment is compact. Further, the material to be kneaded tends to deteriorate due to kneading and melting, and in particular, in the case of a kneading part made of a rotor segment, deterioration due to excessive temperature rise is effectively suppressed, which is preferable.
[0014]
On the other hand, in the above-described apparatus of the present invention, since the vacuum pump is used for vacuum dehydration or devolatilization in both the drying section and the thickening section in the chamber, It is possible that the chemical added to the splatter is scattered in these sections and devolatilized together with moisture, so that the desired thickening effect or the effect of suppressing the decrease in viscosity cannot be obtained.
Therefore, in order to prevent the scattering of the medicine, it is upstream from the medicine supply means and downstream from the vent opening in the drying section, and downstream from the medicine supply means and from the vent opening in the thickening section. It is preferable to provide a resin filling means on the upstream side for filling the space in the chamber with the molten resin.
[0015]
In this case, since the raw material resin is kneaded in a state where the space immediately before the addition of the drug in the chamber or the space immediately after the addition of the drug is filled with the molten resin, the drug is scattered in the drying section and the thickening section. This prevents the chemicals from being mixed into the raw material resin without waste.
For this reason, it is not necessary to estimate an additional amount in anticipation of the scattering of the drug, it is economical because the amount of the drug used can be reduced, and the cross-linking reaction in the chamber becomes stable, which accompanies the scattering of the drug. It is possible to prevent a viscosity variation from occurring in the kneaded resin due to the difference in reaction amount. Further, since the drying section and the thickening section are exactly partitioned by the resin filling means, the inside of these sections can be set to an appropriate degree of vacuum independently of each other.
[0016]
In addition, said resin filling means can be comprised by the reverse flight, kneading disc, or seal ring which were provided in the kneading rotor.
The resin filling means provided on the upstream side of the medicine supply means is a fixed type or movable type having a circular cross section provided in the kneading rotor and an opposing edge for constricting the resin in the chamber facing the circular cross section. A pair of upper and lower gate members of the formula can also be used.
In particular, in the case of the latter gate device, the degree of filling of the resin can be intentionally adjusted by changing the amount of the gap between the upper and lower gate members with respect to the circular cross section, so the kneading time (drying time) in the drying section is adjusted. The effect that it becomes easy is obtained.
[0017]
In addition, as a chemical | medical agent which can be used for this invention, pyrophosphoric acid dianhydride, an antimony trioxide, diphenylmethane-4,4-diisocyanate etc. can be used preferably, However, A high intrinsic viscosity and the good chain length are equal. In particular, diphenylmethane-4,4-diisocyanate is preferable in that the following polymer is obtained.
In order to achieve the second object, the present invention takes the following technical means.
That is, the second device of the present invention is the above-described continuous kneading apparatus for polyester resin, wherein the material supply means includes a dryer for removing moisture from the raw resin, and the raw resin directly connected to the dryer and dried. A storage hopper for storing the water in a moisture-proof state, and openable / closable shutter means interposed between the dryer and the storage hopper.
[0018]
According to the second device of the present invention, the storage hopper is directly connected to the dryer, and the shutter means is interposed between them, so that a predetermined amount of the raw material resin dried by the dryer is placed in the shutter means. After opening and supplying to the storage hopper, the shutter means is closed and the next predetermined amount of the raw material resin is supplied to the dryer, whereby the initial predetermined amount of the raw material resin in the storage hopper is thickened. In the meantime, the next predetermined amount of the raw material resin can be dried, and when the thickening treatment is performed after the raw material resin is previously dried, the drying step and the thickening step of the raw material resin can be performed continuously.
[0019]
In the second apparatus of the present invention, since the raw resin is pre-dried by a dryer separate from the chamber, it is necessary to increase the L / D value of the chamber as in the case of the first apparatus of the present invention. There is also an advantage that a kneader within the range of L / D that is usually employed can be employed.
In the second device of the present invention, the drier need only have a function of drying the raw material resin so that the moisture content is 50 ppm or less, and a hot air drier that circulates hot air to dry, or a dehumidifier. In addition, a dehumidifying dryer or the like that circulates and drys the inert gas can be employed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention.
The continuous kneading apparatus 1 of this embodiment is a biaxial continuous kneading apparatus of a type in which a raw material resin is preliminarily thickened without being subjected to a dryer, and the material supply port 2 at the upstream end and the material discharge at the downstream end. A chamber 4 having an outlet 3 and a pair of left and right kneading rotors 5 rotatably inserted into the chamber 4 are provided.
[0021]
The material supply port 2 of the chamber 4 is connected to a material supply means 6 comprising a supply hopper for receiving the raw material resin from the screw feeder. A plurality of vent ports 7 are provided in the middle of the chamber 4, and two vacuum pumps 8, 9 for depressurizing and dehydrating the interior of the chamber 2 are connected to the vent ports 7. .
The vent port 7 located at the center of the chamber 4 has a medicine supply means 10 comprising a screw feeder or the like for adding a medicine that increases the viscosity of the raw material resin or suppresses its decrease to the chamber 4. A post-processing device 11 made of a pelletizer, a die, or the like is connected to the material discharge port 3 that is connected and located at the downstream end of the chamber 4 via a pressure increasing means such as a gear pump or a single screw extruder.
[0022]
The pair of left and right kneading rotors 5 are connected to a speed reducer 12 and a motor 13 disposed at the upstream end of the chamber 4.
In the present embodiment, the portion upstream of the drug supply means 10 in the chamber 4 is a drying section 14 for kneading while dehydrating the raw material resin before adding the drug under reduced pressure, and is downstream of the drug supply means 10. The portion is a thickening section 15 in which the raw material resin after adding the chemical is kneaded while devolatilizing under reduced pressure.
For this reason, most of the moisture contained in the raw material resin from the beginning is discharged to the outside from each vent port 7 arranged in the drying section 14 by the first vacuum pump 8 together with the moisture accompanying the evaporation due to the heat generated during melting, Impurities such as moisture and ethylene glycol generated during the cross-linking reaction after entering the full-scale thickening treatment are discharged to the outside by the second vacuum pump 9 from each vent port 7 arranged in the thickening section 15. Is done.
[0023]
Of the drying section 14 and the thickening section 15, the first half of the kneading rotor 5 located in the drying section 14 is a kneading composed of a rotor segment having a feed blade twisted in the material feed direction and a return blade twisted in the material return direction. At least one part 16 is provided, and the other part is a feed part 17 having screw blades.
Further, the latter half portion of the kneading rotor 5 located in the thickening section 15 is also provided with at least one kneading portion 16 made of the rotor segment, and the other portion is a feed portion 17 having screw blades.
[0024]
Both the kneading parts 16 can also be constituted by a kneading block having a reverse flight, and the kneading part 16 located in the thickening section 15 has a retention function in which the residence time of the material to be kneaded is 2 minutes or more. It is enough if you have it.
In this embodiment, when the inner diameter of the chamber 4 is D, the axial length of the drying section 14 is L1, and the axial length of the thickening section 15 is L2, L1 / D is 15 or more and 25 The axial length of the chamber 4 is set so that L2 / D is 15 or more and 30 or less.
[0025]
The reason is that it is known that the thickening reaction sufficiently occurs when the water content is reduced to about 50 ppm, but in order to reduce the water content so far, L1 / D is set to 15 or more and sufficient residence time is obtained. It is because it can be achieved by taking. Further, the reason why L1 / D is set to 25 or less is that, after the water content has decreased to around 50 ppm, even if it is set to a longer length, no further dehydration effect can be expected.
The reason why L2 / D is set to 15 or more is that if it is shorter than that, the raw material resin may not be thickened effectively, and L2 / D is set to 30 or less if it is longer than that. This is because the kneading rotor 5 becomes too long and there is a problem in strength, and the kneaded material may be deteriorated.
[0026]
In addition, these numerical ranges can be appropriately set according to various conditions such as the type of the raw resin, whether the raw resin is unused or recycled, or a blend ratio thereof.
[Experimental example]
Next, an experimental example when the polyester resin is actually thickened using the continuous kneader will be described.
First, the experimental conditions are as follows.
[0027]
Recycled PET flakes were used as the raw material resin. The moisture content of the flakes is 5000 ppm and the IV value is 0.70.
A chain extender or a polymerization catalyst was used as an agent (thickener) that increases the viscosity or suppresses the decrease. As the chain extender, pyromellitic dianhydride (manufactured by Daicel Chemical) was used, and the addition rate was 1.0% by weight based on the raw material resin (Experiment Nos. 1 to 5). Moreover, the polymerization catalyst used antimony trioxide, and the addition rate was 200 ppm with respect to raw material resin (experiment number 6).
[0028]
The twin-screw kneading extruder used was KTX-46 manufactured by Kobe Steel, and D = 46φ. The degree of vacuum in the drying section 14 of the twin-screw kneading extruder was 20 Torr, and the degree of vacuum in the thickening section 15 was 5 Torr.
Table 1 shows the results of performing test kneading while changing L1 / D and L2 / D under the above conditions, and measuring the IV value of the kneaded material thus obtained.
In addition, the test kneading when diphenylmethane-4,4-diisocyanate was used as a chain extender was also performed. In this case, all the conditions of the kneader were unified, and the addition amount was changed to 1.0% by weight, 2.0% by weight, and 5.0% by weight with respect to the raw material resin (experiment number 7 to 9).
[0029]
Further, the kneaded material was measured for the weight average molecular weight (Mw) and the number average molecular weight (Mn) by measuring the molecular weight distribution at 40 ° C. using GPC150C manufactured by Waters and using hexafluoroisopropanol as a solvent. ] Is also shown.
Furthermore, when a part of the molten resin was pulled up using tweezers, those that do not easily form good threads are indicated by Δ, and those that become favorable threads are indicated by [Table 1].
[0030]
[Table 1]

[0031]
As is clear from this [Table 1], in the case of Experiment No. 3 where L1 / D is 12, the IV value is reduced to 0.60. This is presumably because the initial moisture content of the raw material resin was not sufficiently removed in the drying section 14 and the crosslinking reaction was hindered by the reaction product generated with the thickening treatment.
Also, in the case of Experiment No. 5 where L2 / D is 40, the IV value is reduced to 0.68. This is probably because the thickening section 15 was too long and the PET resin deteriorated during the thickening treatment.
[0032]
Further, as can be seen by comparing the experiment numbers 2, 4 and 5, when the L2 / D is up to 30, the IV value is improved as the thickening section 15 is lengthened.
Further, it is shown that low IV value fiber spinning was possible for Experiment Nos. 3 to 6, and high IV value fiber spinning was possible for Experiment Nos. 7 to 9, respectively.
Furthermore, in the case of Experiment Nos. 7 to 9 using diphenylmethane-4,4-diisocyanate, the molecular weight distribution (Mw / Mn) is considerably smaller than that of the resin kneaded by adding other chemicals. It can be seen that a good quality polymer with a uniform length can be obtained.
[0033]
FIG. 2 shows a second embodiment of the present invention.
The continuous kneading apparatus 1 of this embodiment is a biaxial continuous kneading apparatus of a type in which a raw material resin is preliminarily dried and then thickened, and includes a chamber 4 having a material supply port 2 and a material discharge port 3, and the chamber 4 And a pair of left and right kneading rotors (not shown) that are rotatably inserted in the interior.
The material supply port 2 of the chamber 4 is provided with a material supply means 21 to be described later, and a drug supply means comprising a screw feeder or the like for adding, into the chamber 4, a drug that increases or decreases the viscosity of the raw material resin. 10 is connected to a material discharge port 3 located at the downstream end of the chamber 4 and a post-processing device 11 made of a pelletizer, a die or the like is connected via a pressure increasing means such as a gear pump or a single screw extruder. .
[0034]
In this embodiment, the material supply means 21 includes a dryer 22 that removes moisture from the raw material resin, a storage hopper 23 that is directly connected to the lower end of the dryer 22 and stores the dried raw material resin in a moisture-proof state, And an openable / closable shutter means 24 interposed between the machine 22 and the storage hopper 23.
The shutter means 24 includes a closing plate that is inserted through the connection opening between the dryer 22 and the storage hopper 23 so as to be horizontally movable, and an actuator including a hydraulic cylinder that opens and closes the closing plate.
[0035]
A supply hopper 26 having an open / close valve 25 is connected to the upper end of the dryer 22, and a stirring blade 27 for stirring the raw material resin is rotatably provided in the dryer 22. Hot air supply / exhaust ports 28 are provided at the upper and lower ends of the dryer 22, and the raw resin in the dryer 22 is dried by supplying / discharging hot air of about 160 ° C. from the supply / discharge ports 28. .
The dryer 22 only needs to have a function of drying the raw material resin so that the moisture content is 50 ppm or less. Besides drying by circulating hot air, the dryer 22 is not dehumidified from the supply / discharge port 28. You may make it dry by circulating active gas.
[0036]
A fixed amount supply means 29 such as a screw feeder is connected to the lower end opening of the storage hopper 23, and the discharge port of the supply means 29 is connected to the material supply port 2 of the chamber 4.
In order to use the continuous kneading apparatus 1 of the present embodiment, a predetermined amount of raw material resin made of recycled PET flakes is supplied to the supply hopper 26, and the open / close valve 25 is opened with the shutter means 24 closed, and the raw material resin is supplied. Supply to dryer 22.
Thereafter, when the hot air drying is completed, the shutter unit 24 is opened to supply a predetermined amount of dry resin to the storage hopper 23, and the resin is pushed into the chamber 4 by the quantitative supply unit 29 to perform a thickening process.
[0037]
Then, while this thickening process is being performed, the next predetermined amount of raw material resin is supplied from the supply hopper 26 to the dryer 22 to perform the drying process, and the previous predetermined amount of raw material resin is thickened. A predetermined amount of the raw material resin that has been dried is supplied to the storage hopper 23 immediately before the processing is completed.
In the present embodiment, the rotational speed of the kneading rotor and the supply / discharge amount of hot air are set so that the drying processing amount in the dryer 22 and the thickening processing amount in the chamber 4 are substantially equal.
[0038]
Thus, according to this embodiment, since the next predetermined amount of raw material can be dried while the initial predetermined amount of raw material resin in the storage hopper 23 is thickened, the raw material resin is previously dried. In the case of carrying out the thickening treatment after 22, the drying step and the thickening step of the raw material resin can be performed continuously.
In the present embodiment, since the raw material resin is pre-dried in advance by a dryer 22 separate from the chamber 4, it is not necessary to increase the L / D value of the chamber 4 as in the case of the first embodiment. A kneader within the L / D range that is usually employed can be employed.
[0039]
In this embodiment as well, a vacuum pump may be connected to the vent port of the chamber 4 in order to discharge the reaction product generated during the thickening process.
Further, if the medicine addition means 10 has finished drying the raw material resin (specifically, the water content is 50 ppm or less), the medicine addition means 10 can supply a part other than the chamber 4 (for example, the storage hopper 23). You can also connect to.
FIG. 3 shows a modification of the second embodiment (FIG. 2), and the continuous kneading apparatus 1 in this case employs a single-screw kneading extruder 30 as a kneading extruder. For this reason, in this modification, the quantitative supply device 29 for forcibly feeding the raw material is not provided, but may be provided as appropriate if necessary.
[0040]
FIG. 4 shows a modification of the first embodiment (FIG. 1). In this case, the continuous kneading apparatus 1 includes a feed unit 17 in the vicinity of the upstream and downstream sides of the medicine supply means 10 in the kneading rotor 5. Is different from the case of the first embodiment in that resin filling means comprising reverse flights 25 and 26 having reverse screw shapes is provided.
That is, in the modified apparatus shown in FIG. 4, the viscosity is increased on the upstream side of the medicine supply means 10, on the downstream side of the most downstream vent port 7 </ b> C in the drying section 14, and on the downstream side of the medicine supply means 10. The reverse flights 25 and 26 are arranged upstream of the most upstream side vent port 7D in the section 15, respectively, so that the space immediately before and immediately after the drug supply means 10 in the chamber 4 is filled with the molten resin, The raw material resin is kneaded.
[0041]
For this reason, since the chemical | medical agent added from the chemical | medical agent supply means 10 is scattered in the drying area 14 or the thickening area | region 15, it will be prevented effectively that it will be attracted | sucked and lose | disappeared from each vent port 7A-7E. The drug can be mixed into the resin without waste, and the quantitative and stable drug supply can be performed.
Further, since the drying section 14 and the thickening section 15 are tightly partitioned by the reverse flights 25 and 26, the sections 14 and 15 can be set to an appropriate degree of vacuum independently of each other.
[0042]
As a member (resin filling means) for filling the space in the chamber 4 with resin, in addition to the reverse flights 25 and 26, a kneading disk or a seal ring provided in the kneading rotor 5 may be adopted. it can.
Such resin filling means may be provided only on the upstream side of the medicine supply means 10.
Furthermore, in the case of the resin filling means provided on the upstream side of the medicine supply means 10, it has a circular cross section provided in the kneading rotor 5 and an opposing edge for constricting the resin in the chamber facing this circular cross section. A gate device having a fixed or movable pair of upper and lower gate members (see, for example, Japanese Patent Publication No. 58-50533) may be employed.
[0043]
In particular, in the case of the gate device, the degree of resin fullness can be intentionally adjusted by changing the amount of the gap between the upper and lower gate members with respect to the circular cross section. There is an advantage that it is easy to adjust.
In addition, as polyester-type resin which can be processed by this invention demonstrated above, both unused polyester-type resin and the recycled polyester-type resin are object.
Examples of the constituent components of the polyester include homopolyesters derived from aliphatic, cycloaliphatic or aromatic dicarboxylic acids and diols, or hydroxycarboxylic acids, or copolyesters (copolymers).
[0044]
Examples of suitable aliphatic carboxylic acids include suberic acid, oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, pimelic acid, adipic acid, sebacic acid, azelaic acid, dimer acid and the like.
Examples of suitable cycloaliphatic dicarboxylic acids include 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3- and 1,4-cyclohexanedicarboxylic acid, 1,3- and 1,4- (Dicarboxymethyl) cyclohexane, 4,4-dicyclohexyl dicarboxylic acid and the like.
[0045]
Suitable aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, o-phthalic acid, 1,3-, 1.4-, 2,6- or 2,7-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid. Examples include acid, 4,4-benzophenone dicarboxylic acid, and 4,4-diphenyl ether dicarboxylic acid.
As the dicarboxylic acid, an aromatic dicarboxylic acid is preferable, and terephthalic acid and isophthalic acid are particularly preferable.
Suitable aliphatic diols include ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 1,3-, 2,3- or 1,4-butanediol, pentyl glycol, neopentyl glycol 1,6-hexanediol, 1,12-dodecanediol, diethylene glycol and the like.
[0046]
Examples of suitable cycloaliphatic diols include 1,4-dihydroxycyclohexane and 1,4-bis (hydroxymethyl) cyclohexane.
Suitable aromatic-aliphatic diols include p-xylene glycol, 2,5-dichloro-p-xylene glycol, 2,2- (β-hydroxyethoxyphenyl) propane, and the like.
As the diol, alkylene glycol, 1,4-dihydroxycyclohexane and 1,4-bis (hydroxymethyl) cyclohexane are preferable, and ethylene glycol and 1,4-butanediol are particularly preferable.
[0047]
The chain extender used as an additive is a generic term for a substance that reacts with an OH group or COOH group at a polyester terminal to extend a molecular chain.
Examples of the chain extender include, as aromatic tetracarboxylic dianhydrides, pyromellitic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,3 ′, 4 , 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride , (Diphenyltetracarboxyl) sulfone dianhydride and the like.
[0048]
Examples of the aliphatic tetracarboxylic dianhydride include cyclobutane 1,2,3,4-tetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, tetrahydrofuran tetracarboxylic dianhydride, and the like. The tetracarboxylic dianhydride is preferably aromatic.
Examples of the diepoxy compound include diglycidyl terephthalate and bisphenol A diglycidyl ether. Examples of the isocyanate compound include diphenylmethane-4,4′-diisocyanate, 1-methylbenzene-2,4-diisocyanate, and hexane-1,6-diisocyanate.
[0049]
The chain extender is not limited to use alone, but can be used in combination with a catalyst that promotes the reaction. For example, a diepoxy compound and an imidazole compound can be used in combination.
The polymerization catalyst used as an additive is one that extends the repeating unit of polyester by deethylene glycol. Examples of the polymerization catalyst include antimony trioxide and germanium dioxide.
Both the chain extender and the polymerization catalyst may be used as agents for improving the viscosity or suppressing the decrease thereof, or only one of them may be used. Moreover, the compounding quantity can be suitably adjusted according to various factors, such as a kind of raw material resin, and processing time.
[0050]
As the chain extender, those described above can be used without any particular limitation, but when diphenylmethane 4,4-diisocyanate is used, the intrinsic viscosity is high and the chain length is uniform (that is, the molecular weight distribution Mw / Mn is small). A polymer is obtained and is particularly preferred.
[0051]
【The invention's effect】
As described above, according to the present invention, in a series of chambers, a raw material resin is once kneaded while dehydrating under reduced pressure without adding a thickening agent, and then added to the raw material resin. In addition, since the raw material resin is kneaded while being devolatilized under reduced pressure, the thickening effect can be further enhanced in the case where the raw material resin is subjected to thickening treatment without being subjected to a dryer in advance.
In addition, according to the present invention, when the raw material resin is subjected to a thickening process after being previously dried, the raw resin drying step and the thickening step can be performed continuously, so that the storage cost of the raw resin can be reduced. .
[Brief description of the drawings]
FIG. 1 is a schematic view of a continuous kneading apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic view of a continuous kneading apparatus according to a second embodiment of the present invention.
FIG. 3 is a schematic view of a continuous kneading apparatus according to a modification of the second embodiment of the present invention.
FIG. 4 is a schematic view of a continuous kneading apparatus according to a modification of the first embodiment of the present invention.
[Explanation of symbols]
1 Continuous kneader
2 Material supply port
3 Material outlet
4 chambers
5 Kneading rotor
6 Material supply means
7 Vent port
8 First vacuum pump
9 Second vacuum pump
14 Drying section
10 Drug supply means
15 Thickening section
16 Kneading part
21 Material supply means
22 Dryer
23 Storage hopper
24 Shutter means
25 Reverse flight (resin filling means)
26 Reverse flight (resin filling means)
L1 Axial length of drying section
L2 Axial length of thickening section
D Inside diameter of chamber

Claims (11)

A chamber (4) having a material supply port (2), a vent port (7) and a material discharge port (3) in that order from the upstream side, and a kneading rotor (5) rotatably inserted into the chamber (4) ), A vacuum pump (8, 9) connected to the vent port (7) to dehydrate the inside of the chamber (4) under reduced pressure, and a material supply means (6) connected to the material supply port (2) And a chemical supply means (10) connected to the chamber (4) so as to add a chemical that increases the viscosity of the raw material resin or suppresses the decrease thereof to the chamber (4). In a continuous kneading apparatus for resin based on
A portion upstream of the drug supply means (10) in the chamber (4) serves as a drying section (14) in which the raw material resin before adding the drug is dehydrated under reduced pressure, and the drug supply means (10) ) Is a thickening section (15) in which the part downstream from the above is kneaded while devolatilizing the raw material resin after the addition of the chemical ,
When the inner diameter of the chamber (4) is D, the axial length of the drying section (14) is L1, and the axial length of the thickening section (15) is L2, L1 / D is 15 or more and 25 or less. A continuous kneading apparatus for a polyester-based resin , wherein the axial length of the chamber (4) is set so that L2 / D is 15 or more and 30 or less . A kneading part (16) having a staying function is provided in a portion of the kneading rotor (5) located in the thickening section (15) so that the residence time of the material to be kneaded in the thickening section (15) is 2 minutes or more. The continuous kneading apparatus for polyester resin according to claim 1 . The polyester according to claim 1 or 2 , wherein the kneading part (16) of the kneading rotor (5) located in the thickening section (15) comprises a kneading block having a rotor segment having a feed blade and a return blade or a reverse flight. -Based resin continuous kneading equipment. Resin filling means (25) for filling the space in the chamber (4) with molten resin upstream from the medicine supply means (10) and downstream from the vent port (7C) in the drying section (14). The continuous kneading apparatus of the polyester-type resin in any one of Claims 1-3 provided. Resin filling means for filling the space in the chamber (4) with molten resin downstream from the medicine supply means (10) and upstream from the vent port (7D) in the thickening section (15). 26) The polyester resin continuous kneading apparatus according to any one of claims 1 to 4 , which is provided with 26). The polyester resin continuous kneading apparatus according to claim 4 or 5 , wherein the resin filling means (25, 26) comprises a reverse flight, a kneading disk or a seal ring provided in the kneading rotor (5). The resin filling means (25) is a fixed or movable type having a circular cross section provided in the kneading rotor (5) and an opposing edge for constricting the resin in the chamber (4) facing the circular cross section. The continuous kneading apparatus for polyester resin according to claim 4 , comprising a pair of upper and lower gate members. In one continuous chamber (4), after kneading the raw material resin supplied into the chamber (4) without adding a chemical that increases or decreases the viscosity of the raw material resin while dehydrating under reduced pressure. , After adding the agent to the raw material resin, kneading the raw material resin under reduced pressure devolatilization ,
A continuous kneading method of a polyester-based resin characterized in that a raw material resin is kneaded in a state where a space immediately before addition of a drug in a chamber (4) is filled with a molten resin . The method for continuously kneading a polyester resin according to claim 8 , wherein the agent is diphenylmethane-4,4-diisocyanate. The method for continuously kneading a polyester resin according to claim 8 or 9 , wherein the raw material resin is kneaded in a state where the space immediately after the addition of the drug in the chamber (4) is filled with the molten resin. A chamber (4) having a material supply port (2) and a material discharge port (3), a kneading rotor (5) rotatably inserted into the chamber (4), and a connection to the material supply port (2) Material supply means (21), and chemical supply means (10) connected to the chamber (4) to add a chemical that increases or decreases the viscosity of the raw material resin into the chamber (4) In a continuous kneading apparatus for polyester resin comprising:
The material supply means (21) includes a dryer (22) that removes moisture from the raw resin, and a storage hopper (23) that is directly connected to the dryer (22) and stores the dried raw resin in a moisture-proof state. ) And openable / closable shutter means (24) interposed between the dryer (22) and the storage hopper (23), and a fixed amount is supplied to the opening below the storage hopper (23). Means (29) is connected, and the discharge port of the quantitative supply means (29) is connected to the material supply port (2) .

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