TW201713407A - Reactor and method for the polymerization of lactide - Google Patents

Abstract

The invention relates to a reactor comprising: a reactor wall that encloses an axially extending cylindrical or substantially cylindrical reactor interior having an axial dimension (h) and a diameter (d) measured perpendicular to the axial dimension, the reactor interior having at least one inlet for reactants and an outlet in a reactor floor; and an axially extending agitator shaft that has at least one axially conveying stirrer element and that extends through the reactor wall into the reactor interior at an upper end of the reactor, characterized in that in the reactor interior an axially extending cylindrical or substantially cylindrical guide tube is arranged that has an axial dimension (h') and an outside diameter (d') measured perpendicular to the axial dimension that defines a guide tube interior so that a space is defined between the reactor wall and the guide tube, the guide tube being spaced from the reactor floor and from the upper end of the reactor interior. The following applies for the ratio of the axial dimension (h') of the guide tube to the axial dimension (h) of the reactor interior: (h'/ h) <= 0.9, and the following applies for the ratio of the outer diameter (d') of the guide tube to the diameter (h) of the reactor interior: (d'/d) <= 0.9, at least one stirring element of the agitator shaft extending into the guide tube interior, and a heat exchanger through which a reaction mixture can flow being arranged within the space.

Description

反應器以及丙交酯聚合方法 Reactor and lactide polymerization method

本發明涉及一反應器，該反應器可以用於聚合、尤其丙交酯的開環聚合。該反應器在此形成為攪拌釜反應器並且具有安排在導管中的攪拌元件。本發明還涉及用於聚合之方法，尤其用於丙交酯的開環聚合，該方法以如下的方式方法進行引導，使得反應混合物的黏度被設定在1與500Pa．s之間。 The present invention relates to a reactor which can be used for the ring opening polymerization of polymerization, especially lactide. The reactor is here formed as a stirred tank reactor and has a stirring element arranged in the conduit. The invention also relates to a process for the polymerization, in particular for the ring-opening polymerization of lactide, which is guided in such a way that the viscosity of the reaction mixture is set at 1 and 500 Pa. Between s.

聚合設施或縮聚設施一般被設計為，使其能夠在額定容量的60%與100%之間、有時還在110%下工作。在50%額定容量以下的容量大多數情況下是不可行的。更大的靈活性以產品質量或工作安全性為代價。例如，在反應器中的產物體積不能超過由構造決定的最小值，而產品的停留時間並不變得比該過程所要求的更大。在較大停留時間下，不良的副產物(例如熱分解的產物)的生成增加，部分該等副產物不再能夠從產物中去除並且影響產物質量。結果係不合規格的產物，如染色、聚合物的熔點降低等等。在容量下限附近的設施運行容易導致運行受干擾，如聚合物的凝固(Einfrieren)、由於頻率變換器過熱導致的泵故障、經歷放熱的聚合反應。此類干擾可能由於反應器的緊急清空和設施零件的損壞，由產物損失而導致多日的生產故障。 Polymerization facilities or polycondensation facilities are generally designed to operate between 60% and 100% of rated capacity, and sometimes still 110%. Capacity below 50% of rated capacity is not feasible in most cases. Greater flexibility comes at the expense of product quality or work safety. For example, the product volume in the reactor cannot exceed the minimum determined by the construction, and the residence time of the product does not become greater than that required by the process. At larger residence times, the formation of undesirable by-products (e.g., products of thermal decomposition) increases, and some of these by-products are no longer able to be removed from the product and affect product quality. The result is substandard products such as dyeing, a decrease in the melting point of the polymer, and the like. Operation of facilities near the lower limit of capacity is prone to disturbances in operation, such as solidification of the polymer, pump failure due to overheating of the frequency converter, and polymerization undergoing exotherm. Such disturbances may result in multiple days of production failure due to product loss due to emergency emptying of the reactor and damage to facility components.

US 5,484,882(大日本公司)提出一兩階段ROP(尤其丙交酯)，使用與帶有靜態混合元件的管式反應器相聯繫的一攪拌釜或循環反應器。作為在 攪拌釜中預聚合的特徵，提及的是錨式攪拌器和用於排出預聚物的齒輪泵。 US 5,484,882 (Great Japan) proposes a two-stage ROP (especially lactide) using a stirred tank or recycle reactor associated with a tubular reactor with static mixing elements. As in The characteristics of the prepolymerization in the stirred tank are mentioned with an anchor stirrer and a gear pump for discharging the prepolymer.

WO 2010/012770 A1(Purac)提到具有在第一階段中的連續型混合反應器的一兩階段方法，該混合反應器可以實施為循環反應器或攪拌釜。在第一階段中實現的“聚合度”(係指大概的轉化率)為5與90%之間。沒有進一步提出該攪拌釜變體的特徵。 WO 2010/012770 A1 (Purac) refers to a two-stage process with a continuous mixing reactor in the first stage, which can be implemented as a recycle reactor or a stirred tank. The "degree of polymerization" (referred to as the approximate conversion rate) achieved in the first stage is between 5 and 90%. The characteristics of the stirred tank variant are not further proposed.

在EP 2 188 047(UIF)中描述了一用於製造PLA之方法，該方法以兩步執行丙交酯的ROP。第一步在於丙交酯在攪拌釜或循環反應器中的預聚合，第二步在於在管式反應器中的聚合。該預聚合在第1步中導致在5與70mol%之間、較佳的是在30與60mol%之間的丙交酯轉化率。管式反應器將聚合進一步引導直至化學平衡，該化學平衡依據溫度處於95與97%之間的轉化率。沒有提及在攪拌釜中的預聚合的其他特徵。 A method for the manufacture of PLA is described in EP 2 188 047 (UIF), which performs the ROP of lactide in two steps. The first step consists in the prepolymerization of lactide in a stirred tank or in a recycle reactor, the second step being the polymerization in a tubular reactor. This prepolymerization results in a lactide conversion between 5 and 70 mol%, preferably between 30 and 60 mol%, in the first step. The tubular reactor further directs the polymerization until chemical equilibrium, which is between 95 and 97% conversion depending on the temperature. No other features of prepolymerization in the stirred tank are mentioned.

在開環聚合(ROP)在攪拌釜中實際實現時，遇到了一系列的問題，對於該等問題，先前技術沒有提出解決方案。 When the ring-opening polymerization (ROP) is actually carried out in a stirred tank, a series of problems have been encountered, and the prior art has not proposed a solution to such problems.

在丙交酯“在塊體中(in Masse)”的開環聚合過程中，即在沒有溶劑的丙交酯熔體中，聚合物熔體的黏度隨著丙交酯轉換大幅度提高。在攪拌釜中ROP的連續執行允許聚合用的產物的黏度在反應器中不超過一允許的範圍。特別在工業措施中，一現存的攪拌構造只有在向上和向下都受限制的黏度範圍內才能保證反應器內容物的最優的混合。過高的黏度由於對安全裝置的要求造成攪拌器的停機，該等安全裝置避免了驅動電機或傳動器的超載或者攪拌器的變形。此類停機導致在釜中的進一步的溫度和黏度升高並因而導致排出的問題、靜態的設施驅動器(具有不合規格的產物以至在產物中斷或產物損失情況下反應器的緊急清空)的更長的中斷。 In the ring-opening polymerization of lactide "in masse", ie in a lactide melt without solvent, the viscosity of the polymer melt increases significantly with the lactide conversion. The continuous execution of ROP in the stirred tank allows the viscosity of the product for polymerization to not exceed a permissible range in the reactor. Particularly in industrial practice, an existing agitating configuration ensures optimum mixing of the reactor contents only in a restricted viscosity range both upwards and downwards. Excessive viscosity The agitator is shut down due to the requirements of the safety device, which avoids overloading of the drive motor or actuator or deformation of the agitator. Such shutdowns result in increased temperature and viscosity in the kettle and thus lead to problems with discharge, longer static facility drives (with substandard products and even emergency rinsing of the reactor in the event of product interruption or product loss) The interruption.

過低的黏度導致在下游連接的管式反應器中與過強的反向混合、過低的轉化率和過低的莫耳質量相關的問題。這在攪拌釜自身中導致，設計用於更高黏度的攪拌器不再帶來所設置的混合功率和輸送功率。例如，在反應器中形成再循環區域和出現的漩渦，該等再循環區域和漩渦影響與其餘反應器內容物的物料交換，並且因此妨礙所有的反應器內容物的均勻混合。過低的黏度可以在極端情況下使混合作用和傳輸功率完全停滯。在攪拌釜中聚合時符合有限的黏度範圍係對於該方法和整個設施的經濟的運行的前提條件。 Too low viscosity leads to problems associated with excessive reverse mixing, too low conversion and too low molar quality in downstream connected tubular reactors. This results in the agitator itself, and the agitator designed for higher viscosity no longer brings the set mixing power and delivery power. For example, recirculation zones and emerging vortices are formed in the reactor that affect material exchange with the rest of the reactor contents and thus impede uniform mixing of all reactor contents. Too low a viscosity can completely delay the mixing and transmission power in extreme cases. A limited viscosity range for polymerization in a stirred tank is a prerequisite for the economic operation of the process and the entire facility.

丙交酯的ROP反應係放熱的，也就是每莫耳轉化的丙交酯產生約23.3kJ的熱量。這引起攪拌器驅動功率最終在反應器中產物中轉變成熱量。在靜止狀態下，熱必須從釜中正在反應的熔體排出。理論上對此而言足夠的是，所送入的單體(丙交酯)的溫度保持為在反應器中的產品溫度以下一確定的值並且於是該產物隨著送入而冷卻。為此所要求的在所送入的丙交酯與在反應器中的產物之間的溫度差從簡單的熱平衡得出並且依據轉化率和丙交酯的光學純度而處於約在10與50℃之間。然而實際上，藉由所送入的丙交酯的溫度來調節釜中產物的溫度係不足的。在反應器中的混合過程延緩了調節性改變送入溫度的效果。這個空滯時間隨著在反應器中存在的產物量且因此隨著設施容量而增加。難以保持該設施的隨時間恆定的產物質量。 The ROP reaction of lactide is exothermic, that is, about 23.3 kJ of heat per mole of lactide converted. This causes the agitator drive power to eventually transform into heat in the product in the reactor. At rest, heat must be removed from the melt being reacted in the kettle. In theory it is sufficient that the temperature of the monomer (lactide) fed is kept below a certain temperature of the product temperature in the reactor and the product is then cooled as it is fed. The temperature difference between the fed lactide and the product in the reactor required for this purpose is derived from a simple thermal equilibrium and is at about 10 and 50 ° C depending on the conversion and the optical purity of the lactide. between. In practice, however, the temperature of the product in the kettle is adjusted to be insufficient by the temperature of the lactide fed. The mixing process in the reactor retards the effect of modulating the change in the feed temperature. This lag time increases with the amount of product present in the reactor and therefore with facility capacity. It is difficult to maintain a constant product quality of the facility over time.

在工作參數大幅度改變(例如所送入的丙交酯的溫度浮動和通過量浮動)時，但特別是在未預見的工作狀態下，如電力故障或從反應器排出產物時故障，例如由於在下游連接的機組中的干擾，則增大了聚合在過高或過低產品溫度的方向“跑偏”的危險。在此轉化率、莫耳質量和熔體黏度隨著產物溫度不可控地提升直至攪拌器故障。另一方面，在過於遲緩的溫度調節和高轉化率下，產 物的熔點可以升高並且使釜內容物凝固。在此情況下，必須快速地自釜中的熔體抽出或送入熱，以便阻止設施停機和生產故障(可能為最多數日)。與釜的緊急清空相關的產物損失也影響生產的經濟性。 When the operating parameters are drastically changed (for example, the temperature fluctuation of the fed lactide and the throughput fluctuation), but especially in unforeseen operating conditions, such as power failure or failure of product discharge from the reactor, for example due to Interference in the downstream connected units increases the risk of the polymer "running off" in the direction of too high or too low product temperatures. Here, the conversion, molar mass and melt viscosity increase uncontrollably with product temperature until the stirrer fails. On the other hand, under too slow temperature regulation and high conversion rate, The melting point of the substance can be raised and the contents of the kettle can be solidified. In this case, heat must be quickly drawn or sent from the melt in the kettle to prevent facility downtime and production failures (possibly for up to several days). The loss of product associated with the emergency emptying of the kettle also affects the economics of production.

如在所有化學設施中一樣，設施容量越大，生產越經濟。大的設施容量同樣意味著在反應器中大的產物體積。隨著設施容量的提高，在同樣的平均停留時間下，在攪拌釜反應器中傳熱面積與產物體積的比率降低。在中試規模(也就是具有約100kg內容物的釜)的丙交酯ROP過程中，藉由釜的外壁的熱量送入或送出仍然是足夠的，但在工業規模的反應器(也就是具有大於1000kg內容物的釜)中，則不再可行。大的容量要求ROP攪拌釜的特別的構造特徵，以便在規模擴大時保持傳熱面積對反應器體積的比率恆定。 As in all chemical facilities, the greater the capacity of the facility, the more economical the production. Large facility capacity also means a large product volume in the reactor. As the facility capacity increases, the ratio of heat transfer area to product volume in the stirred tank reactor decreases at the same average residence time. In the lactide ROP process on a pilot scale (that is, a kettle with about 100 kg of contents), it is still sufficient to feed or send out the heat from the outer wall of the kettle, but in an industrial scale reactor (that is, In a kettle of more than 1000 kg of content, it is no longer feasible. The large capacity requires special construction features of the ROP stirred tank to maintain a constant ratio of heat transfer area to reactor volume as the scale is expanded.

不僅溫度的調節和因此反應器中的轉化率，而且還有規模擴大，都要求在反應器內部中的加熱或冷卻面積。 Not only the temperature regulation and hence the conversion rate in the reactor, but also the scale-up, requires heating or cooling areas in the interior of the reactor.

然而反應器中加熱和冷卻面積的安排與所希望的在設施容量方面的靈活性係衝突的：在聚合反應器中的產物液位必須保持在所安裝的熱交換器之上。如果產物液位較低，則產物並未沖刷部分或全部的加熱或冷卻面積。黏附在面上的熔體膜不被交換緩慢地聚合，直到產生一高韌性層。在進一步的聚合中，所黏附的產物的熔點甚至可以升高到超過反應器中的產物溫度，使其構成固態的聚合物層。這樣的韌性或固態的層阻止了熱傳遞、經受熱分解、當液位再次上升時部分從面上脫落、並且於是污染產物。安裝的熱交換器減小了反應器中液位的游隙並且因此減小了容量方面的靈活性。 However, the arrangement of the heating and cooling zones in the reactor conflicts with the desired flexibility in terms of facility capacity: the product level in the polymerization reactor must remain above the installed heat exchanger. If the product level is low, the product does not flush some or all of the heating or cooling area. The melt film adhered to the face is not slowly polymerized by exchange until a high toughness layer is produced. In further polymerization, the melting point of the adhered product may even rise above the temperature of the product in the reactor to form a solid polymer layer. Such a tough or solid layer prevents heat transfer, undergoes thermal decomposition, partially detaches from the surface when the liquid level rises again, and then contaminates the product. The installed heat exchanger reduces the play of the liquid level in the reactor and thus reduces the flexibility in terms of capacity.

液態的供應物(丙交酯)以及催化劑、引發劑和其他在適當時必要的添加劑必須儘量快速且完全地與反應器中存在的所有產物體積進行混合。其 他情況下，調節轉化率和產物黏度的空滯時間過大並且造成這個參數的大幅度波動。這種要求隨著在反應器中增長的產物體積而越來越難滿足。攪拌器的驅動功率和傳動轉矩隨著攪拌器直徑的5次冪升高。因為攪拌器直徑和反應器體積強制性地彼此相關聯，反應器容量的擴大影響到經濟性和材料可載入性的界限。 The liquid supply (lactide) as well as the catalyst, initiator and other additives necessary as appropriate must be mixed as quickly and completely as possible with all product volumes present in the reactor. its In his case, the lag time for adjusting the conversion and product viscosity is too large and causes large fluctuations in this parameter. This requirement is increasingly difficult to meet with the volume of product that grows in the reactor. The drive power and transmission torque of the agitator increase with the fifth power of the agitator diameter. Since the agitator diameter and the reactor volume are forcibly associated with each other, the expansion of the reactor capacity affects the limits of economy and material loadability.

【發明目的】[Object of the Invention]

從EP 2 188 047(UIF)出發，目的係提供一種方法和設備，其係用於在連續運行的攪拌釜中的預聚合。 Starting from EP 2 188 047 (UIF), the object is to provide a process and apparatus for prepolymerization in a continuously operating stirred tank.

在PLA生產中較大的優點係，一現有聚合設施的容量能夠靈活地匹配市場的要求(浮動的需求、對緩慢升高的需求的匹配)。因此，用於製造PLA的設施應當在能夠靈活地在額定容量的25%與100%之間的容量下工作，同時保持產品質量。對於這一工作方式，需要一種方法和適合於此的設備。 A major advantage in PLA production is that the capacity of an existing polymerization facility can flexibly match market requirements (floating demand, matching for slowly increasing demand). Therefore, the facility used to manufacture the PLA should be able to operate flexibly at a capacity between 25% and 100% of the rated capacity while maintaining product quality. For this mode of operation, a method and equipment suitable for this is needed.

【目的的實現】[Implementation of purpose]

因此本發明涉及如專利申請專利範圍第1項所述之反應器，該反應器尤其適合於丙交酯的開環聚合。本發明還涉及如專利申請專利範圍第14項所述之聚合方法，尤其丙交酯的開環聚合方法。在此，相應的從屬專利申請專利範圍形成了有利的改進方案。 The invention therefore relates to a reactor as described in claim 1 of the patent application, which reactor is particularly suitable for ring opening polymerization of lactide. The invention further relates to a polymerization process as described in claim 14 of the patent application, in particular a ring opening polymerization process of lactide. Here, the corresponding dependent patent application patent scope forms an advantageous development.

本發明因此涉及一反應器，包括：一反應器壁部，該反應器壁部圍成一軸向延伸的圓柱形或實質上圓柱形的反應器內部空間，該反應器內部空間包括一軸向的尺度(h)和一垂直於該軸向尺度測量的直徑(d)，其中該反應器內部 空間具有至少一個用於反應物的入口以及在反應器底部的一出口；一軸向延伸的攪拌軸，該攪拌軸具有至少一個軸向輸送的攪拌元件，該攪拌軸在該反應器的一上端通過該反應器壁部引入到該反應器內部空間中，其中在該反應器內部空間中安排有一軸向延伸的圓柱形或實質上圓柱形的引導管，該引導管具有一軸向尺度(h’)和一垂直於該軸向尺度測量的外直徑(d’)並限定一引導管內部空間，使得在該反應器壁部與該引導管之間形成一空間，其中該引導管與該反應器底部並且與該反應器內部空間的上端間隔開，其中對於該引導管的軸向尺度(h’)與該反應器內部空間的軸向尺度(h)的比率為：(h’/h)0.9，對於該引導管的外直徑(d’)與該反應器內部空間的直徑(d)的比率為：(d’/d)0.9，其中該攪拌軸用至少一個攪拌元件延伸直到該引導管內部空間中，並且在該空間之內安排有一能夠由反應混合物流過的熱交換器。 The invention thus relates to a reactor comprising: a reactor wall portion enclosing an axially extending cylindrical or substantially cylindrical reactor interior, the reactor interior including an axial direction a dimension (h) and a diameter (d) measured perpendicular to the axial dimension, wherein the reactor interior has at least one inlet for the reactant and an outlet at the bottom of the reactor; an axially extending agitation a shaft having at least one axially conveying agitating element introduced into the reactor internal space through an end of the reactor at an upper end of the reactor, wherein one of the reactor internal spaces is arranged An axially extending cylindrical or substantially cylindrical guide tube having an axial dimension (h') and an outer diameter (d') perpendicular to the axial dimension and defining a guide tube interior space Forming a space between the wall of the reactor and the guide tube, wherein the guide tube is spaced from the bottom of the reactor and from the upper end of the inner space of the reactor, wherein the axial extent of the guide tube (H ') a ratio with the internal space of the reactor axial dimension (h) of: (h' / h) 0.9, the ratio of the outer diameter (d') of the guide tube to the diameter (d) of the inner space of the reactor is: (d'/d) 0.9, wherein the agitating shaft extends with at least one agitating element up to the inner space of the guiding tube, and a heat exchanger capable of flowing through the reaction mixture is arranged within the space.

出人意料地已經確定，藉由在該反應器中安排一個或多個攪拌元件(其中至少一個安排在引導管中)對向該反應器中輸入的反應混合物進行完全混合能夠與藉由熱交換器對反應器內容物的強制旋轉進行組合。這個攪拌器負責在最小與最大之間所有的填充狀態下旋轉所有的反應器內容物，使得所送 入的稀液態的丙交酯熔體、催化劑和引發劑以及在適當時抑制劑在短時間內且完全地與反應器內容物混合。軸向混合避免了形成具有徑向速度分量的自身循環的區域，該等區域僅在很大延遲下才與其餘的反應器內容物混合。 Surprisingly, it has been determined that by arranging one or more agitating elements (at least one of which is arranged in the guiding tube) in the reactor, the complete mixing of the reaction mixture input into the reactor can be carried out by means of a heat exchanger The forced rotation of the contents of the reactor is combined. This agitator is responsible for rotating all reactor contents in all filling states between minimum and maximum, so that the The dilute liquid lactide melt, catalyst and initiator are introduced and, where appropriate, the inhibitor is mixed with the reactor contents in a short time and completely. Axial mixing avoids the formation of areas of self-circulation with radial velocity components that are only mixed with the rest of the reactor contents with great delay.

藉由熱交換器的強制旋轉能夠快速加熱或冷卻反應器內容物並且由此支持產物溫度和轉化率的調節。強制旋轉完全利用了在最小與最大之間的任何填充狀態下在構造方面可提供的加熱或冷卻面積，並且確保提供所要求的加熱或冷卻功率，並且使該反應向過高或過低的產物溫度方向上的“偏離”係在調節過程上可掌控的。此外，避免了產物中的大溫度差。 The forced rotation of the heat exchanger enables rapid heating or cooling of the reactor contents and thereby supports adjustment of product temperature and conversion. Forced rotation takes full advantage of the heating or cooling area that can be provided in construction in any filling state between minimum and maximum, and ensures that the required heating or cooling power is provided and that the reaction is over- or under-product The "deviation" in the temperature direction is controllable in the adjustment process. In addition, large temperature differences in the product are avoided.

出人意料地已經發現，安排在一引導管中的攪拌器藉由安排在該反應器中的熱交換器不僅能夠實現軸向混合的任務還能夠實現反應器內容物的強制旋轉。 Surprisingly, it has been found that the agitator arranged in a guide tube not only enables the task of axial mixing but also enables forced rotation of the contents of the reactor by means of a heat exchanger arranged in the reactor.

根據一較佳的實施方式，該引導管以其下端與該反應器壁部以一間距(a)間隔開，使得在該具有至少一個軸向輸送的攪拌元件的攪拌軸工作時該反應器混合物的壓力損失(作為在來自引導管的出口處與在引導管與反應器壁之間的空間中的入口處的反應器混合物的壓力差來測量)最大為在流過該熱交換器時該反應器混合物的壓力損失(作為在進入該熱交換器的入口處與來自該熱交換器的出口處的反應器混合物的壓力差來測量)的10%，及/或在該反應器底部的投影中測量的間距(a)相對於該反應器內部空間的軸向尺度(h)為0.001a/h0.25，較佳的是0.01a/h0.2，特別較佳的是0.05a/h0.15。 According to a preferred embodiment, the guide tube is spaced apart from the reactor wall by a distance (a) at its lower end such that the reactor mixture is operated when the agitator shaft having at least one axially conveyed agitating element is operated. Pressure loss (measured as the pressure difference of the reactor mixture at the outlet from the pilot tube and at the inlet in the space between the pilot tube and the reactor wall) is maximally the reaction when flowing through the heat exchanger 10% of the pressure loss of the mixture (measured as the pressure difference at the inlet to the heat exchanger and the reactor mixture from the outlet of the heat exchanger), and/or in the projection at the bottom of the reactor The measured pitch (a) is 0.001 with respect to the axial dimension (h) of the internal space of the reactor. a/h 0.25, preferably 0.01 a/h 0.2, particularly preferably 0.05 a/h 0.15.

對於該引導管的軸向尺度(h’)與該反應器內部空間的軸向尺度(h)的比率較佳為：0.05(h’/h)0.5，較佳的是0.075(h’/h)0.4，特別較佳的是0.1(h’/h)0.25。 The ratio of the axial dimension (h') of the guide tube to the axial dimension (h) of the internal space of the reactor is preferably: 0.05 (h'/h) 0.5, preferably 0.075 (h'/h) 0.4, particularly preferably 0.1 (h'/h) 0.25.

替代或附加地同樣較佳的是，對於該引導管的外直徑(d’)與該反應器內部空間的直徑(d)的比率為：0.2(d’/d)0.6，較佳的是0.3(d’/d)0.5。 Alternatively or additionally, it is also preferred that the ratio of the outer diameter (d') of the guide tube to the diameter (d) of the inner space of the reactor is: 0.2 (d'/d) 0.6, preferably 0.3 (d'/d) 0.5.

另一個較佳的實施方式提出，該引導管內部空間具有一垂直於該軸向尺度測量的內直徑(x)並且該至少一個攪拌元件中的至少一者具有一垂直於該軸向尺度測量的旋轉直徑(y)，其中對於比率y/x為：0.9(y/x)0.99，較佳的是0.95(y/x)0.98。 Another preferred embodiment provides that the inner space of the guide tube has an inner diameter (x) measured perpendicular to the axial dimension and at least one of the at least one agitating element has a measurement perpendicular to the axial dimension. Rotation diameter (y), where the ratio y/x is: 0.9 (y/x) 0.99, preferably 0.95 (y/x) 0.98.

此外較佳的是，該熱交換器的一軸向尺度與該引導管的軸向尺度(h’)相等或最大與之相等。 Further preferably, the axial dimension of the heat exchanger is equal to or maximally equal to the axial dimension (h') of the guide tube.

還有利的是，引導管和反應器內部空間是同心安排的，使得該空間設計為環形或基本上環形。 It is also advantageous that the guide tube and the internal space of the reactor are arranged concentrically such that the space is designed to be annular or substantially annular.

該反應器底部在此可以形成為錐形，其中該出口安排在該錐形的尖端處，其中該錐形的開口角度較佳的是>50°，進一步較佳的是55°至120°，特別較佳的是60°至100°。 The bottom of the reactor may be formed as a cone here, wherein the outlet is arranged at the tip end of the cone, wherein the angle of the opening of the cone is preferably > 50°, further preferably 55° to 120°, Particularly preferred is 60° to 100°.

同樣可行的是，該攪拌軸通過該反應器壁部的貫通部(Durchführung)具有一熱隔離器，該熱隔離器較佳的是能夠用一液態或蒸氣態的熱載體來驅動。 It is also possible for the agitator shaft to have a thermal isolator through the through-wall portion of the reactor wall, which is preferably driven by a heat carrier in a liquid or vapor state.

進一步較佳的是，該攪拌軸在軸向方向上在該引導管的上邊緣與該反應器內部空間的上端之間的區域中具有至少一個另外的軸向輸送的攪拌元件。 It is further preferred that the agitating shaft has at least one further axially conveying agitating element in the axial direction in the region between the upper edge of the guiding tube and the upper end of the inner space of the reactor.

在此，以下的變體係可行的並且是相對較佳的。 Here, the following variants are feasible and relatively preferred.

該至少一個另外的攪拌元件在此可以設計為分成兩個部分，使得在該攪拌軸工作時用該至少一個另外的軸向輸送的攪拌元件在一在軸向方向 的投影中對應於該引導管內部空間的區域中產生與一在該軸向方向的投影中對應於該空間的區域中在軸向方向上反向的流動。 In this case, the at least one further agitating element can be designed to be divided into two parts, so that the at least one additional axially fed agitating element is used in the axial direction when the agitating shaft is in operation. The region of the projection corresponding to the inner space of the guide tube produces a flow that is opposite to the axial direction in a region corresponding to the space in the projection in the axial direction.

還同樣可行的是，該至少一個另外的攪拌元件排他地形成在一在軸向方向的投影中對應於該引導管內部空間的區域中。 It is also possible for the at least one further stirring element to be exclusively formed in a region in the projection in the axial direction corresponding to the inner space of the guide tube.

替代於此同樣可行和較佳的是，該至少一個另外的攪拌元件排他地形成在一在軸向方向的投影中對應於在反應器壁部與引導管之間形成的空間的區域中。 Alternatively, it is also possible and preferred that the at least one further stirring element is exclusively formed in a region in the projection in the axial direction corresponding to the space formed between the reactor wall and the guide tube.

根據另一個有利的實施方式，該至少一個另外的軸向輸送的攪拌元件具有一垂直於軸向方向延伸的尺度(z)，其中對於該尺度(z)與該反應器內部空間的尺度(d)的比率為：0.7(z/d)0.99，較佳的是0.8(z/d)0.98，特別較佳的是0.9(z/d)0.98。 According to a further advantageous embodiment, the at least one further axially conveyed stirring element has a dimension (z) which extends perpendicular to the axial direction, wherein the dimensions (z) and the dimensions of the internal space of the reactor are The ratio is: 0.7 (z/d) 0.99, preferably 0.8 (z/d) 0.98, particularly preferably 0.9 (z/d) 0.98.

此外可行的是，該攪拌軸形成為共軸的，使得該至少一個攪拌元件和該至少一個另外的攪拌元件能夠不依賴於彼此而被致動。一個此類的攪拌軸例如具有兩個彼此共軸安排的攪拌軸，藉由該等攪拌軸，這兩組攪拌元件，即安排在該引導管中的一個或多個攪拌元件以及安排在該引導管上方的一個或多個攪拌元件，能夠不依賴於彼此而被致動。 It is furthermore possible for the agitating shaft to be formed coaxial so that the at least one agitating element and the at least one further agitating element can be actuated independently of one another. One such agitating shaft has, for example, two agitating shafts arranged coaxially with each other, by means of the agitating shafts, the two sets of agitating elements, ie one or more agitating elements arranged in the guiding tube, and arranged in the guiding One or more agitating elements above the tube can be actuated independently of each other.

還有利的是，該攪拌元件選自由卡普蘭攪拌器(Kaplanrührern)，傾斜葉片攪拌器，螺旋攪拌器，槳葉攪拌器，交叉葉片攪拌器所組成的群組，及/或該至少一個另外的攪拌元件選自由傾斜葉片攪拌器，交叉葉片攪拌器，帶有連續或間斷線圈的線圈攪拌器，帶式攪拌器和具有相對於旋轉平面傾斜的多個臂的錨式攪拌器所組成的群組。 It is also advantageous if the stirring element is selected from the group consisting of a Kaplan mixer, a tilting blade stirrer, a screw stirrer, a paddle stirrer, a cross blade agitator, and/or the at least one additional The agitating element is selected from the group consisting of a tilted blade agitator, a cross blade agitator, a coil agitator with continuous or intermittent coils, a belt agitator and an anchor agitator having a plurality of arms inclined relative to the plane of rotation .

此外存在以下可能性：在該引導管與該反應器內部空間的上端 間隔開的區域中存在至少一個另外的引導管。 In addition, there is the possibility of at the upper end of the guide tube and the internal space of the reactor. There is at least one additional guide tube in the spaced apart region.

同樣可行的是，該引導管具有一在軸向方向上在該反應器內部空間的上端的方向上延伸的突出部，該突出部具有穿孔及/或設計為孔板。該引導管的軸向尺度在此情況下在不考慮該突出部的情況下確定。 It is also possible for the guide tube to have a projection which extends in the axial direction in the direction of the upper end of the inner space of the reactor, the projection having a perforation and/or as an orifice plate. The axial dimension of the guide tube is determined in this case without regard to the projection.

根據一特別較佳的實施方式，該引導管在該反應器內部空間中在軸向方向上如下定位，使得導向在該反應器中的反應混合物的最小填充高度的反應混合物最小填充量(在該最小填充量下該引導管的上邊緣浸沒到該反應混合物中)在2h的平均停留時間下小於該反應器的額定容量下的填充量的50%。 According to a particularly preferred embodiment, the guide tube is positioned in the inner space of the reactor in the axial direction such that the minimum filling level of the reaction mixture leading to the minimum filling height of the reaction mixture in the reactor is The upper edge of the guide tube was submerged into the reaction mixture at a minimum fill level of less than 50% of the fill capacity at the nominal capacity of the reactor at an average residence time of 2 h.

另一個有利的實施方式提出，該反應器壁部係可調溫的，較佳的是劃分為在多個在軸向方向上安排的分開地可調溫的區域，特別較佳的是具有三個分開地可調溫的區域(I，II，III)，其中一第一可調溫區域(I)在軸向方向上從該反應器底部直到該引導管的一上端形成，一第二可調溫區域(II)在軸向方向上在該引導管的一上端以上形成，並且一第三可調溫區域(III)在該第二區域(II)以上形成並且包括該反應器壁部的一上端(反應器蓋)。 A further advantageous embodiment provides that the wall of the reactor is temperature-sensitive, preferably divided into a plurality of separately temperature-adjustable regions arranged in the axial direction, particularly preferably having three a separately temperature-adjustable region (I, II, III), wherein a first temperature-adjustable region (I) is formed in the axial direction from the bottom of the reactor to an upper end of the guide tube, and a second a temperature regulating zone (II) is formed above an upper end of the guiding tube in the axial direction, and a third temperature adjustable zone (III) is formed above the second zone (II) and includes the reactor wall One upper end (reactor cover).

有利的是，該引導管及/或該至少一個另外的引導管形成為雙層壁的並且能夠由一在環境條件及/或工作條件下液態的熱載體來調溫。 Advantageously, the guide tube and/or the at least one further guide tube are formed as double-walled and can be tempered by a heat carrier which is liquid under ambient conditions and/or operating conditions.

尤其可行的是，該攪拌軸在藉由該反應器壁部的貫通部處或前方、以及在該反應器底部，在兩處安置該攪拌軸。 It is especially feasible that the agitator shaft is placed at two locations at or near the through portion of the reactor wall and at the bottom of the reactor.

該熱交換器在此尤其設計為管式熱交換器。 In this case, the heat exchanger is embodied in particular as a tube heat exchanger.

在此可行的是，該熱交換器包括由垂直於軸向方向延伸的蛇管(Rohrschlangen)組成的管束，在環境條件及/或工作條件下液態的熱載體流動通過該等蛇管，其中該反應混合物在周圍沖刷(umspült)該等管或蛇管。 In this case, the heat exchanger comprises a tube bundle consisting of a coil extending perpendicularly to the axial direction through which the liquid heat carrier flows under ambient conditions and/or operating conditions, wherein the reaction mixture Flush (umspült) the tubes or coils around.

同樣可行的是，該熱交換器包括一封閉的管體，該管體具有在軸向方向上延伸的、穿過該管體的管，其中產物通過該等管流動，該等管在該封閉的管體中被在環境條件及/或工作條件下液態的熱載體在周圍沖刷。 It is also practicable that the heat exchanger comprises a closed tubular body having a tube extending in the axial direction through the tubular body through which the product flows, the tubes being closed in the tube The body of the tube is flushed around the liquid carrier under ambient conditions and/or operating conditions.

該熱交換器同樣可以包括在軸向方向上延伸的管或蛇管，在環境條件及/或工作條件下液態的熱載體通過該等管或蛇管流動，其中該反應混合物在周圍沖刷該等管或蛇管。 The heat exchanger may likewise comprise a tube or coil extending in the axial direction through which the liquid heat carrier flows under ambient conditions and/or operating conditions, wherein the reaction mixture flushes the tubes or Snake tube.

此外，本發明涉及用於丙交酯聚合之方法，尤其使用上文所述的根據本發明之反應器，其中藉由調節該反應混合物的反應溫度，將該丙交酯轉化率和因此該反應混合物的黏度設定為在1至100Pa．s之間、較佳的是5至50Pa．s的值並且保持恆定。“恆定”在本發明意義上理解為，所設定的黏度的偏差小於20%、較佳的是小於10%。這係如下實現的：所使用的丙交酯的轉化率保持恆定或者保持基本上恆定。 Furthermore, the invention relates to a process for the polymerization of lactide, in particular using the reactor according to the invention as described above, wherein the conversion of the lactide and thus the reaction is carried out by adjusting the reaction temperature of the reaction mixture The viscosity of the mixture is set to be between 1 and 100 Pa. Between s, preferably 5 to 50 Pa. The value of s is kept constant. "Constant" is understood in the sense of the invention to mean that the deviation of the set viscosity is less than 20%, preferably less than 10%. This is achieved as follows: the conversion of the lactide used remains constant or remains substantially constant.

例如可以藉由如下方式進行調節，使得在恆定的通過量(也就是說恆定的容量)下丙交酯送入速率連同該反應混合物中的催化劑濃度、該反應混合物中的引發劑濃度及/或在該反應混合物中的抑制劑濃度一起固定地預先提供，並且該反應混合物的溫度被調節為使得該轉化率-並且因此由該轉化率得出的黏度-在前述浮動範圍的背景下保持恆定。 For example, the adjustment can be made such that at a constant throughput (that is to say a constant capacity) the lactide feed rate together with the catalyst concentration in the reaction mixture, the initiator concentration in the reaction mixture and/or The inhibitor concentration in the reaction mixture is fixedly supplied in advance, and the temperature of the reaction mixture is adjusted such that the conversion rate - and thus the viscosity derived from the conversion rate - remains constant in the context of the aforementioned floating range.

對於該反應器的容量改變、尤其降低的情況，藉由調節該轉化率確保了該黏度在前述浮動範圍的背景下保持恆定。在這種情況下這例如是如下進行的，該丙交酯轉化率和因此在額定容量的25%與100%之間容量下在該反應器中的黏度藉由改變溫度及/或在反應混合物中的催化劑濃度及/或引發劑濃度及/或抑制劑濃度及/或該反應器的填充狀態而保持恆定。 For the capacity change, especially the reduction of the reactor, it is ensured that the viscosity remains constant in the context of the aforementioned floating range by adjusting the conversion. In this case, for example, the lactide conversion and thus the viscosity in the reactor at a capacity between 25% and 100% of the nominal capacity can be varied by changing the temperature and/or in the reaction mixture. The catalyst concentration and/or initiator concentration and/or inhibitor concentration and/or the filling state of the reactor are kept constant.

出人意料地已可以確定，藉由設定及/或調解單體轉化率、尤其藉由選擇在開環聚合過程中的產物溫度、催化劑濃度、引發劑濃度及/或抑制劑濃度，能夠將該反應器中產物的黏度設定在約1至100Pa．s、較佳的是5-50Pa．s的範圍內且保持恆定。在這個黏度範圍內，本發明反應器的攪拌元件可以實現反應器內容物的最優混合。 Surprisingly, it has been determined that the reactor can be set up by setting and/or mediating monomer conversion, in particular by selecting the product temperature, catalyst concentration, initiator concentration and/or inhibitor concentration during the ring opening polymerization process. The viscosity of the product is set at about 1 to 100 Pa. s, preferably 5-50Pa. Within the range of s and kept constant. Within this viscosity range, the agitating elements of the reactor of the present invention allow for optimal mixing of the reactor contents.

在此在該反應器中反應混合物的溫度對轉化率和因此直接對該反應混合物的黏度具有實質影響。本發明之方法因此尤其可以藉由調節該反應混合物的溫度而受到影響。 Here, the temperature of the reaction mixture in the reactor has a substantial effect on the conversion and thus the viscosity of the reaction mixture directly. The process of the invention can therefore be influenced in particular by adjusting the temperature of the reaction mixture.

產物溫度的調節可以尤其藉由將送入溫度的調節與藉由一安裝在該反應器中的熱交換器(該熱交換器可以加熱以及冷卻反應器內容物)的經調節的熱量送入和送出的組合來實現並且因此獲得所希望的黏度。為此目的，該熱交換器較佳的是用液態熱載體工作，該熱載體在該釜之外被設定到所希望的溫度和所希望的物質流量並且送入到該釜中的熱交換器中。 The adjustment of the temperature of the product can be carried out, inter alia, by adjusting the feed temperature and the conditioned heat by means of a heat exchanger installed in the reactor which heats and cools the contents of the reactor. The combination sent out is achieved and thus the desired viscosity is obtained. For this purpose, the heat exchanger preferably operates with a liquid heat carrier which is set outside the tank to a desired temperature and a desired mass flow rate and which is fed to the heat exchanger in the kettle. in.

藉由在該反應器中所包含的熱交換器，同樣可以在規模擴大時使傳熱面積與反應體積的比率得以保持。例如在中試規模的具有108kg反應質量的反應器中，使用有1m²的加熱和冷卻面積可用的雙夾套係足夠的(見下文實例1)。在工業規模的反應器中，也就是具有1000kg和以上的反應質量，對應於500kg/h和更多的額定容量，為了達到必需的加熱和冷卻效率，該雙夾套面積係不足的。本發明的熱交換器(較佳的是安排在該反應器中)提供了例如11m²/m³的傳熱面積與反應體積的比率。 By the heat exchanger included in the reactor, it is also possible to maintain the ratio of the heat transfer area to the reaction volume when the scale is enlarged. For example, in a pilot scale reactor having a reaction mass of 108 kg, a double jacket available with a heating and cooling area of 1 m ² is sufficient (see Example 1 below). In industrial scale reactors, i.e. having a reaction mass of 1000 kg and above, corresponding to a nominal capacity of 500 kg/h and more, the double jacket area is insufficient in order to achieve the necessary heating and cooling efficiencies. The heat exchanger of the present invention (preferably arranged in the reactor) provides a ratio of heat transfer area to reaction volume of, for example, 11 m ² /m ³ .

藉由與本發明的方法相關的措施，出人意料地發現，在相同的轉化率下實現了直至該反應器的額定容量的25%的容量降低。這尤其藉由以下措 施來實現，該等措施相應地可以單獨但也可以彼此組合地應用：在該反應器的額定容量的100%下，藉由適當選擇釜中的產物溫度、催化劑投料和引發劑投料，設定了在5%與80%、較佳的是30%與60%之間的所希望的丙交酯轉化率並且保持恆定。如果用在額定容量的25%與<100%之間的降低的通過量來運行該釜，則藉由降低釜中的熔體液位將轉化率保持恆定，其中停留時間、產物溫度、產物中的催化劑濃度和引發劑濃度保持相同。如果再次實現了由構造導致的最小填充狀態(在下文段落中闡釋)，則該轉化率藉由降低產物溫度而保持恆定。如果產物溫度不再提供游隙，則藉由降低在產物中的催化劑濃度或藉由投料抑制劑、較佳的是濃乳酸，該轉化率得以保持。出人意料地已經發現，在相同的丙交酯轉化率和因此相同的產物質量下，連續運行的攪拌釜反應器能夠以此方式運行直到額定容量的25%的最小容量。 By means of the measures associated with the process of the invention, it has surprisingly been found that a reduction in capacity up to 25% of the nominal capacity of the reactor is achieved at the same conversion. This is especially the case Accordingly, the measures can be applied individually or in combination with each other: at 100% of the rated capacity of the reactor, by appropriately selecting the product temperature in the kettle, the catalyst charge and the initiator charge, The desired lactide conversion is between 5% and 80%, preferably between 30% and 60% and remains constant. If the kettle is operated with a reduced throughput between 25% and <100% of the nominal capacity, the conversion is kept constant by lowering the melt level in the kettle, where residence time, product temperature, product The catalyst concentration and initiator concentration remain the same. If the minimum fill state resulting from the construction is again achieved (explained in the paragraph below), the conversion is kept constant by lowering the product temperature. If the product temperature no longer provides play, the conversion is maintained by lowering the catalyst concentration in the product or by feeding a inhibitor, preferably concentrated lactic acid. Surprisingly, it has been found that a continuously operating stirred tank reactor can be operated in this manner up to a minimum capacity of 25% of the nominal capacity at the same lactide conversion and thus the same product quality.

多種措施的聯合允許釜中的熔體液位保持在如下高度，使得熱交換器在25%的最小容量下也總是保持被熔體遮蓋。由此可以將熱交換器的面積完全用於調節產物溫度。熱交換器總是用熔體沖刷。於是防止聚合物層在熱交換器面上沈積。 The combination of various measures allows the melt level in the kettle to be maintained at a level such that the heat exchanger is always kept covered by the melt at a minimum capacity of 25%. The area of the heat exchanger can thus be used completely to regulate the product temperature. The heat exchanger is always flushed with the melt. The polymer layer is then prevented from depositing on the heat exchanger side.

根據本發明方法的一較佳的實施方式，該反應混合物的溫度設定在120與200℃之間、較佳的是在130與170℃之間並且在那裡保持恆定。 According to a preferred embodiment of the process of the invention, the temperature of the reaction mixture is set between 120 and 200 ° C, preferably between 130 and 170 ° C and is kept constant there.

不依賴於此或者與此相結合，該反應混合物中的催化劑濃度可以設定在5與100ppm之間、較佳的是在15與60ppm之間，其中該催化劑較佳的是選自由錫、鋅、鈦和鋯的有機化合物所組成的群組。對於上述金屬有機化合物的示例性情況，上面提出的較佳的濃度範圍在此涉及在該反應混合物中的金屬原子的濃度，對於一有機的、不含金屬的催化劑的示例性情況，上面提出的 較佳的濃度範圍在此涉及該催化劑分子的濃度。 Without depending on or in combination, the concentration of the catalyst in the reaction mixture may be set between 5 and 100 ppm, preferably between 15 and 60 ppm, wherein the catalyst is preferably selected from the group consisting of tin, zinc, A group of organic compounds of titanium and zirconium. For the exemplary case of the above metalorganic compound, the preferred concentration range set forth above herein relates to the concentration of metal atoms in the reaction mixture, for the exemplary case of an organic, metal-free catalyst, set forth above A preferred concentration range here relates to the concentration of the catalyst molecule.

還同樣可行的是，尤其作為單獨的措施或與先前或此後所提及的方法選項群組合，在該反應混合物中的引發劑濃度被設定為在0與30mmol/kg之間，其中該引發劑較佳的是選自由一價、二價、三價或更高價的醇類所組成的群組。 It is also possible, in particular as a separate measure or in combination with a method option group mentioned before or after, the initiator concentration in the reaction mixture is set between 0 and 30 mmol/kg, wherein the initiator Preferred is a group selected from the group consisting of monovalent, divalent, trivalent or higher alcohols.

還同樣可行的是，向反應混合物添加一抑制劑。在此較佳的是，該抑制劑選自由接酸，較佳的是乳酸，特別較佳的是具有80至100%濃度的含水乳酸所組成的群組，並且在該反應混合物中的抑制劑濃度被設定為，使得在聚合時出現的反應混合物具有在5與15之間、較佳的是5與10mmol/kg之間的接基濃度。 It is also possible to add an inhibitor to the reaction mixture. Preferably, the inhibitor is selected from the group consisting of acid, preferably lactic acid, particularly preferably aqueous lactic acid having a concentration of 80 to 100%, and an inhibitor in the reaction mixture. The concentration is set such that the reaction mixture which occurs during the polymerization has a binder concentration of between 5 and 15, preferably between 5 and 10 mmol/kg.

另一個較佳的實施方式提出，該反應混合物的溫度藉由所送入的丙交酯的量及/或溫度及/或借助於該熱交換器及/或藉由送入該熱交換器的熱載體的量及/或溫度來調節。 Another preferred embodiment provides that the temperature of the reaction mixture is increased by the amount and/or temperature of the lactide fed and/or by means of the heat exchanger and/or by means of the heat exchanger. The amount and/or temperature of the heat carrier is adjusted.

尤其借助於在該引導管中的該至少一個攪拌元件建立至少100mbar的動態壓力(Staudruck)。 In particular, a dynamic pressure of at least 100 mbar is established by means of the at least one stirring element in the guide tube.

根據本發明方法還較佳的是，該反應混合物在軸向方向上以大於該反應器通過量10倍且較佳的是大於30倍的速率旋轉。 It is further preferred according to the process of the invention that the reaction mixture is rotated in the axial direction at a rate greater than 10 times the throughput of the reactor and preferably greater than 30 times.

根據本發明之方法，要求該熱交換器及/或該引導管完全被該反應混合物遮蓋。 According to the method of the invention, the heat exchanger and/or the guide tube are required to be completely covered by the reaction mixture.

尤其該方法在對應於該反應器的額定容量的10%至100%、較佳的是15至100%、特別較佳的是20至100%的容量下進行。然而，在使用本發明方法時可以採用的本發明反應器的具體設計還允許在不影響產物質量的情況 下在小於額定容量的100%、例如額定容量的<80%或者<60%或者<40%下實現該方法的經濟的運行。本發明之方法因此使得尤其在使用本發明反應器時實現極其靈活的方法過程，這涉及容量。在此尤其出人意料的是，在不同的反應器容量下轉化率和黏度能夠保持在相同的值。 In particular, the process is carried out at a capacity corresponding to 10% to 100%, preferably 15 to 100%, particularly preferably 20 to 100%, of the rated capacity of the reactor. However, the specific design of the reactor of the invention which can be employed when using the process of the invention also allows for the case where the quality of the product is not affected. The economic operation of the process is achieved at less than 100% of the rated capacity, for example <80% or <60% or <40% of the nominal capacity. The process according to the invention thus makes it possible to achieve an extremely flexible process process, in particular when using the reactor of the invention, which relates to capacity. It is particularly surprising here that the conversion and viscosity can be kept at the same value at different reactor capacities.

對於該引導管具有一突出部的情況，對於前文所述的較佳的實施方式，在額定容量方面保持一填充度，在該填充度下該引導管完全浸入到該反應混合物中並且僅僅該穿孔的突出部-對於對應的較低的填充度的情況-在適當時從該反應混合物伸出。 In the case where the guide tube has a projection, for the preferred embodiment described above, a degree of filling is maintained in terms of nominal capacity at which the guide tube is completely immersed in the reaction mixture and only the perforation The protrusion - for the corresponding lower degree of filling - extends from the reaction mixture as appropriate.

對於一另外的在熱交換器上方的具有攪拌器的引導管的情況，僅該具有熱交換器的下引導管被熔體遮蓋。 In the case of an additional guide tube with a stirrer above the heat exchanger, only the lower guide tube with the heat exchanger is covered by the melt.

丙交酯的轉化率較佳的是設定在5與80%之間、較佳的是在30與60%之間。 The conversion of lactide is preferably set between 5 and 80%, preferably between 30 and 60%.

同樣較佳的是，該反應混合物在該反應器中的平均停留時間被設定為最大4小時，較佳的是最大2小時。平均停留時間由反應體積相對於通過的反應混合物的體積流量得出。反應體積係在反應器中存在的反應混合物的體積。 It is also preferred that the average residence time of the reaction mixture in the reactor is set to a maximum of 4 hours, preferably a maximum of 2 hours. The average residence time is derived from the reaction volume relative to the volumetric flow rate of the passed reaction mixture. The reaction volume is the volume of the reaction mixture present in the reactor.

本發明方法的一另外的較佳的實施方式提出，該反應器殼體的第一可調溫區域被設定到較佳的是在120與200℃之間、較佳的是在130與170℃之間的反應混合物溫度，並且該反應器殼體的第三可調溫區域被設定在丙交酯的熔點與被設定為小於該第一可調溫區域溫度的溫度之間的溫度。第二區域的溫度依據該反應器的填充狀態來選擇。對於該填充狀態被選擇為與該引導管的上邊緣一樣高的情況，較佳的是，對於該反應器壁部的第二可加熱部分，選 擇與在第三部分中的主導溫度相同的溫度。對於在該反應器中的填充狀態更高的情況，較佳的是，在該第二可調溫區域中選擇與在該反應器壁部的第一區域中相同的溫度。 A further preferred embodiment of the method of the invention provides that the first temperature adjustable region of the reactor housing is set to preferably between 120 and 200 ° C, preferably at 130 and 170 ° C. The temperature of the reaction mixture is between, and the third temperature adjustable region of the reactor housing is set at a temperature between the melting point of the lactide and the temperature set to be less than the temperature of the first temperature adjustable region. The temperature of the second zone is selected depending on the filling state of the reactor. For the case where the filling state is selected to be as high as the upper edge of the guide tube, preferably, for the second heatable portion of the reactor wall portion, Select the same temperature as the dominant temperature in the third section. In the case where the filling state in the reactor is higher, it is preferred to select the same temperature in the second temperature-adjusting region as in the first region of the reactor wall portion.

在此提出的方法尤其是連續運行的，也就是說連續地將反應物或尚未進行反應的反應混合物加入該反應器中並且連續地取出產物。該反應器的填充狀態在運行過程中可以改變，然而也可以保持恆定。 The method proposed here is in particular continuous operation, that is to say continuously adding reactants or reaction mixtures which have not yet been reacted to the reactor and continuously withdrawing the product. The filling state of the reactor can be varied during operation, but can also be kept constant.

1‧‧‧反應器 1‧‧‧reactor

2‧‧‧反應器壁部 2‧‧‧Reactor wall

3‧‧‧反應器內部空間 3‧‧‧Reactor internal space

4‧‧‧出口 4‧‧‧Export

5‧‧‧攪拌元件 5‧‧‧ stirring element

5’‧‧‧攪拌元件 5'‧‧‧ stirring element

5”‧‧‧攪拌元件 5"‧‧‧ stirring elements

6‧‧‧攪拌軸 6‧‧‧Agitator shaft

7‧‧‧引導管 7‧‧‧Guide tube

7’‧‧‧引導管 7’‧‧‧Guide tube

7”‧‧‧突出部 7"‧‧‧Protruding

8‧‧‧內部空間 8‧‧‧Internal space

9‧‧‧空間 9‧‧‧ Space

10‧‧‧熱交換器元件 10‧‧‧ heat exchanger components

I‧‧‧區域 I‧‧‧ area

II‧‧‧區域 II‧‧‧Area

III‧‧‧區域 III‧‧‧Area

h‧‧‧高度 H‧‧‧height

h’‧‧‧尺度 H’‧‧‧ scale

d‧‧‧直徑 D‧‧‧diameter

d’‧‧‧外直徑 D’‧‧‧outer diameter

V_最小‧‧‧最小填充液位 V _minimum ‧ ‧ minimum fill level

V_最大‧‧‧最大填充狀態 V _max ‧ ‧ maximum filling status

x‧‧‧內直徑 X‧‧‧ inner diameter

y‧‧‧旋轉直徑 y‧‧‧Rotary diameter

z‧‧‧尺度 Z‧‧‧ scale

在附圖中：〔圖1〕示出根據本發明的反應器之第一設計方式。 In the drawings: [Fig. 1] shows a first design of a reactor according to the invention.

〔圖2〕示出根據本發明的反應器之另一個設計方式。 [Fig. 2] shows another design of the reactor according to the present invention.

〔圖3〕示出根據本發明的反應器之另一個設計方式。 [Fig. 3] shows another design of the reactor according to the present invention.

〔圖4〕示出根據本發明的反應器之另一個設計方式。 [Fig. 4] shows another design of the reactor according to the present invention.

〔圖5〕示出根據本發明的反應器之另一個設計方式。 [Fig. 5] shows another design of the reactor according to the present invention.

以下借助於附圖和實施方式詳細闡釋本發明，然而所作出的實施方式僅僅是示例性質的並且不應理解為對於本發明主題有限制性。 The invention is explained in detail below with the aid of the drawings and the embodiments, but the embodiments made are merely exemplary and should not be construed as limiting the subject matter of the invention.

在此使用以下的定義： Use the following definitions here:

黏度：Viscosity:

在本文中總是指動態黏度。 In this paper, it always refers to dynamic viscosity.

ROP：ROP:

開環聚合 Ring opening polymerization

額定容量：Rated Capacity:

反應器或聚合設施被設計用於的通過量，以kg/h計。 The throughput that the reactor or polymerization facility is designed for, in kg/h.

容量：capacity:

反應器或聚合設施實際工作時的通過量，以kg/h計。 The throughput of the reactor or polymerization facility in actual operation, in kg/h.

Mw：Mw:

聚合物的平均分子量(重量平均) Average molecular weight of the polymer (weight average)

平均停留時間：Average stay time:

每以kg/h計的產物通過量下以kg計的反應器中的產物質量或者每產物體積流量下在反應器中的產物體積 The product mass per kg/h of product in the reactor, or the product volume in the reactor per unit volume flow rate

轉化率：Conversion rates:

轉化率U(以%計)從所測量的樣品的丙交酯濃度x和送入反應器的丙交酯濃度x₀如下地計算： U=[1-(x/x₀)]．100%；x和x₀係質量百分數。 The conversion rate U (in %) is calculated from the measured lactide concentration x of the sample and the lactide concentration x ₀ fed to the reactor as follows: U = [1-(x/x ₀ )]. 100%; x and x ₀ are mass percentages.

圖1示出根據本發明的反應器1的第一本發明設計方式。為了如上所述地操作該方法，尤其為了實現必需的產物混合、溫度調節和容量減小，需要一適合的設備。本發明的攪拌釜反應器1包括一圓柱形的部分，在該部分下方安置一錐形底部。該錐形尖端匯入到用於產物的出口4中。在出口中安置了一齒輪泵，該齒輪泵負責從反應器1中定量地取出熔體。錐形的出口使得從靜止工作的反應器1中排出更容易。在運行故障時，例如在未預計的黏度升高 時，該出口使產物排出、排出泵的填充和釜的清空更容易。該錐形的開口角度為較佳的是大於60°。更小的角度在產物取出和清空方面不再提供更多的優點，但是導致在錐形尖端中較差的混合區域和該設備的增大的建造高度。反應器1在此具有一反應器壁部2，該反應器壁部形成為雙層壁的。雙層壁的反應器壁部2在此劃分為三個分開的區域I、II和III，該等區域I、II和III在此可分別由液態的熱載體介質流過並且因此可被分開地加熱。反應器壁部2圍成一反應器內部空間3。反應器1具有一用於反應物的入口(未示出)以及一出口4，該出口安排在底部側。反應器1在此在軸向方向上延伸，這個軸在圖1中示出為豎直的。一在軸向方向上延伸的攪拌軸6從蓋部(該反應器的上端)穿過。反應器內部空間3在此具有高度h，該高度從出口4直到反應器內部空間3的上端而確定。反應器內部空間3在此具有直徑d。在反應器1的下部區域中存在一引導管7，該引導管具有一內直徑x以及一外直徑d’。該引導管在此具有一軸向形成的尺度h’。在反應器的內側的壁部與引導管之間形成的空間9中引入一熱交換器元件10，該熱交換器元件在圖1的示例性情況下形成一環形延伸的管束。在引導管7的內部空間8中在該攪拌軸6處安置一攪拌元件5，該攪拌元件在引導管7中能夠產生所存在的反應混合物的軸向流動。在本實例中，攪拌元件5係一螺旋攪拌器。此處，在反應器1中包含的反應混合物在致動在引導管中的帶有攪拌元件5的攪拌軸6時向下輸送，使得反應混合物在從引導管7退出之後藉由反應器壁部轉向並且在環形的空間9中在引導管7與反應器外壁部之間進入並且在那裡強制性地藉由熱交換器10向下輸送。反應器在此是在圖1中用元件符號V_最小標出的最小填充液位與在圖1中用元件符號V_最大標出的最大填充狀態之間可工作的。額外地，在攪拌軸6處存在另外的攪拌元件5’和5”，該等攪拌元件安排在 引導管上方。如在圖1中可以看出的，這個額外的攪拌元件在此形成在該反應器的兩個區域中，一直接安排在攪拌軸6處的攪拌元件5”在所標識的攪拌軸旋轉方向將反應混合物向下輸送(在相反的旋轉方向時向上輸送)，而安排在反應器1的壁部2處的一外部的攪拌元件5’將反應混合物向上(在相反的旋轉方向時向下)輸送。 Figure 1 shows a first inventive design of a reactor 1 according to the invention. In order to operate the process as described above, in particular in order to achieve the necessary product mixing, temperature regulation and capacity reduction, a suitable device is required. The stirred tank reactor 1 of the present invention comprises a cylindrical portion below which a conical bottom is placed. The tapered tip merges into the outlet 4 for the product. A gear pump is placed in the outlet, which is responsible for the quantitative withdrawal of the melt from the reactor 1. The tapered outlet makes it easier to discharge from the stationary reactor 1. In the event of a malfunction, for example, when the unpredicted viscosity increases, the outlet makes it easier to discharge the product, fill the discharge pump and empty the kettle. The angle of the opening of the cone is preferably greater than 60°. Smaller angles no longer provide more advantages in product removal and emptying, but result in a poor mixing zone in the tapered tip and an increased build height of the device. The reactor 1 here has a reactor wall 2 which is formed as a double wall. The double-walled reactor wall 2 is here divided into three separate regions I, II and III, which can here be respectively flowed by a liquid heat carrier medium and can thus be separated heating. The reactor wall 2 encloses a reactor internal space 3. The reactor 1 has an inlet (not shown) for the reactants and an outlet 4 which is arranged on the bottom side. The reactor 1 here extends in the axial direction, this axis being shown as vertical in FIG. An agitating shaft 6 extending in the axial direction passes through the cap portion (the upper end of the reactor). The reactor internal space 3 here has a height h which is determined from the outlet 4 up to the upper end of the reactor internal space 3. The reactor internal space 3 here has a diameter d. In the lower region of the reactor 1, there is a guide tube 7 having an inner diameter x and an outer diameter d'. The guide tube here has an axially formed dimension h'. A heat exchanger element 10 is introduced into the space 9 formed between the inner wall of the reactor and the guide tube, which heat exchanger element forms an annularly extending tube bundle in the exemplary case of FIG. A stirring element 5 is arranged in the inner space 8 of the guide tube 7 at the agitating shaft 6, which is capable of producing an axial flow of the reaction mixture present in the guiding tube 7. In the present example, the agitating element 5 is a spiral agitator. Here, the reaction mixture contained in the reactor 1 is conveyed downward when actuating the stirring shaft 6 with the stirring element 5 in the guiding tube, so that the reaction mixture passes through the wall of the reactor after exiting from the guiding tube 7 In the annular space 9 , the guide tube 7 and the outer wall of the reactor enter and are forced to be conveyed downwards by the heat exchanger 10 . The reactor used here is _{the smallest} element symbol marked V in FIG. 1 with a minimum filling level between a maximum filling state of working with _{the largest} element symbol marked V in FIG. 1. Additionally, there are additional agitating elements 5' and 5" at the agitator shaft 6, which are arranged above the guiding tube. As can be seen in Figure 1, this additional agitating element is formed here in the reaction Of the two zones of the apparatus, a stirring element 5" arranged directly at the agitator shaft 6 transports the reaction mixture downward in the direction of rotation of the identified agitator shaft (upward in the opposite direction of rotation) and is arranged in the reactor An external agitating element 5' at the wall 2 of 1 conveys the reaction mixture upwards (downward in the opposite direction of rotation).

在圖2中展示反應器1的另一個修改形式，為了簡明起見，已經在圖1中用於相同部件的元件符號在圖2中沒有標示。與圖1所示的反應器不同，圖2中所示的反應器1在引導管7中具有一不同的攪拌器5。額外地，在圖2中所示的反應器1與圖1中所示的反應器1的不同之處在於安排在該引導管7上方的在該攪拌軸處的其他的攪拌元件5’、5”。如圖2中所示，該攪拌軸在此形成為共軸的，也就是說該攪拌軸由兩個共軸地安排在彼此中的、可分開驅動的攪拌軸組成。藉由內部的攪拌軸可驅動在引導管7中安排的攪拌元件5，藉由外部的攪拌軸可驅動另外的攪拌元件5’、5”。 Another modification of the reactor 1 is shown in Fig. 2. For the sake of brevity, the component symbols already used in Fig. 1 for the same components are not indicated in Fig. 2. Unlike the reactor shown in Fig. 1, the reactor 1 shown in Fig. 2 has a different agitator 5 in the guide tube 7. Additionally, the reactor 1 shown in Figure 2 differs from the reactor 1 shown in Figure 1 in that other agitating elements 5', 5 are arranged above the guiding tube 7 at the agitating shaft. As shown in Fig. 2, the agitating shaft is formed here to be coaxial, that is to say the agitating shaft is composed of two separately displaceable stirring shafts arranged coaxially with each other. The agitator shaft can drive the agitating element 5 arranged in the guide tube 7, and the other agitating elements 5', 5" can be driven by an external agitating shaft.

圖3示出本發明反應器1的另一個類型，在此已經在先前的附圖中用於相同部件的元件符號為了簡明起見已經去掉。與根據圖1和2的反應器1不同，這個反應器對於所有的攪拌元件5’、5”分別具有相同的類型和相同的輸送方向。在所示的實例中，在攪拌軸附近的中央區域中的攪拌元件向下輸送。由此產生在反應器壁附近的周邊區域中向上的流動。此外替代於根據圖1和2的管束熱交換器10，安排有一由豎直安排的管組成的熱交換器10，其中熱載體可以在該等管中引導且熔體可以在該等管周圍引導。替代地還可行的是一熱交換器10，該熱交換器根據機器人蒸發器的先前技術安排在兩個管底部之間，該等管底部在下方和上方與中央的引導管齊平地終止。 Figure 3 shows another type of reactor 1 of the invention, in which the component symbols for the same components have been removed in the previous figures for the sake of brevity. In contrast to the reactor 1 according to Figures 1 and 2, this reactor has the same type and the same conveying direction for all the stirring elements 5', 5" respectively. In the example shown, in the central region near the stirring shaft The agitating element is transported downwards. This results in an upward flow in the peripheral region near the reactor wall. Furthermore, instead of the tube bundle heat exchanger 10 according to Figures 1 and 2, a heat consisting of vertically arranged tubes is arranged. An exchanger 10 in which a heat carrier can be guided in the tubes and a melt can be guided around the tubes. Alternatively, a heat exchanger 10 can be used, which is arranged according to the prior art of the robotic evaporator. Between the bottoms of the two tubes, the bottoms of the tubes terminate flush with the central guide tube below and above.

圖4示出一如在圖3中展示的反應器，然而在該最上部的攪拌元件5”的高度上存在一另外的引導管7’，該引導管用於在最大液位與熱交換器10之間的區域中在反應器1中的反應混合物的更好的軸向充分混合。 Figure 4 shows a reactor as shown in Figure 3, however at the height of the uppermost stirring element 5" there is an additional guiding tube 7' for the maximum liquid level and heat exchanger 10 Better axial full mixing of the reaction mixture in reactor 1 between the zones.

圖5示出圖4中所示的反應器類型的另一個替代方案。在此，在引導管7上方鄰接一突出部7”，該突出部形成為用於使熔體通過，例如形成為孔板。 Figure 5 shows another alternative to the type of reactor shown in Figure 4. Here, a projection 7" is adjoined above the guide tube 7, which is formed for passage of the melt, for example as an orifice plate.

下文的實施方式總體上適用於全部附圖、特定屬於單個附圖的細節如上所提出的。 The following embodiments are generally applicable to all of the figures, details of which are specific to the individual figures, as set forth above.

反應器1的蓋可以任意地成形。較佳的是盤形或半橢圓形底部(Klöpper-oder Korbbogenboden)，在該底部的中央安排有一用於攪拌軸6的貫通部。在該貫通部中有一熱隔離器，該熱隔離器用一液態或蒸氣態的熱載體工作。該熱隔離器藉由加熱攪拌軸6防止從反應器1中穿過軸6的熱流出。由此阻止了在某些熱量不足的工作狀態下固態聚合物凝固到攪拌軸6上。 The lid of the reactor 1 can be arbitrarily shaped. A disk-shaped or semi-elliptical bottom (Klöpper-oder Korbbogenboden) is preferred, and a through portion for the agitating shaft 6 is arranged in the center of the bottom. There is a thermal isolator in the through portion, the thermal isolator being operated with a heat carrier in a liquid or vapor state. The thermal isolator prevents heat flow from the reactor 1 through the shaft 6 by heating the agitator shaft 6. This prevents the solid polymer from solidifying onto the agitator shaft 6 under certain heat-deficient operating conditions.

反應器1的外壁與該蓋和在反應器1中安裝的熱交換器同樣是可加熱的或可冷卻的，較佳的是借助於在環境溫度和工作溫度下液態的熱載體。較佳的是使用如下液體作為熱載體，其沸點和閃點高於220℃並且其凝固點低於-10℃且是無毒的。高閃點降低了***保護上的成本。無毒性致使在設施中少量洩露時對工作人員和環境沒有危險並且也不會污染產物。 The outer wall of the reactor 1 is likewise heatable or coolable to the lid and the heat exchanger installed in the reactor 1, preferably by means of a heat carrier which is liquid at ambient and operating temperatures. It is preferred to use a liquid as a heat carrier having a boiling point and a flash point higher than 220 ° C and a freezing point lower than -10 ° C and which is non-toxic. The high flash point reduces the cost of explosion protection. Non-toxicity results in a small amount of leakage in the facility and is not hazardous to workers and the environment and does not contaminate the product.

反應器1的外部加熱器劃分成多個區域I、II、III，該等區域能夠以不同的溫度工作。有利的是，在反應器外罩中直至該反應器1的填充直至的高度，設定與在反應器1中的產物同樣的溫度。這使得產物溫度的調節更容易，並且避免了過熱和聚合物膜在反應器1的內壁上的凝固。還有利的是，用更 低的溫度加熱在填充狀態以上的反應器外罩，尤其在最大液位以上以及在容器蓋中，該溫度在丙交酯熔點與反應器1中的產物溫度之間。由此可行的是，避免固態丙交酯重昇華到內壁上並且產生液態的丙交酯膜，該丙交酯膜在重力下回流到產物中。因為聚合物可溶解在單體中，所以這種自然的回流阻止聚合物層生長到壁上且因此阻止反應器1的污染和產物被分解的聚合物的污染。 The external heater of the reactor 1 is divided into a plurality of zones I, II, III which are capable of operating at different temperatures. It is advantageous to set the same temperature as the product in the reactor 1 in the reactor jacket up to the filling of the reactor 1 up to the height. This makes adjustment of the product temperature easier and avoids overheating and solidification of the polymer film on the inner wall of the reactor 1. It is also beneficial to use more The low temperature heats the reactor jacket above the filled state, especially above the maximum liquid level and in the vessel lid, which is between the melting point of lactide and the product temperature in reactor 1. It is thus possible to avoid solid sublimation of the lactide onto the inner wall and to produce a liquid lactide film which is refluxed into the product under gravity. Since the polymer is soluble in the monomer, this natural backflow prevents the polymer layer from growing onto the wall and thus prevents contamination of the reactor 1 and contamination of the product by the decomposed polymer.

在反應器1的下部區域中，一軸向輸送的攪拌器5在一引導管7中工作。作為攪拌器類型適合的是螺旋攪拌器、卡普蘭攪拌器、傾斜葉片、交叉葉片或槳葉攪拌器。這種攪拌器產生在排出方向上向下的強制流動。該流動在錐形的底部轉向並且引導到在引導管與反應器壁2之間的環形空間9中。在這個空間9中安排有熱交換器10。為了用熔體實現強制的通過流，其豎直的延伸被限制在該引導管7的高度。引導管7的上邊緣與熱交換器10的上邊緣組合在一起。這條水平線限定了反應器中的最小液位。只有這樣才能在最小液位下保持由熔體遮蓋傳熱面積並且同時保持從外部流入到引導管中。 In the lower region of the reactor 1, an axially fed agitator 5 operates in a guide tube 7. Suitable as agitator type are spiral agitators, Kaplan mixers, inclined blades, cross blades or paddle mixers. This agitator produces a forced flow downward in the discharge direction. This flow is diverted at the bottom of the cone and directed into the annular space 9 between the guide tube and the reactor wall 2. A heat exchanger 10 is arranged in this space 9. In order to achieve a forced flow through the melt, its vertical extension is limited to the height of the guide tube 7. The upper edge of the guide tube 7 is combined with the upper edge of the heat exchanger 10. This horizontal line defines the minimum level in the reactor. This is the only way to keep the heat transfer area covered by the melt at the minimum liquid level while maintaining the flow from the outside into the guide tube.

圍繞引導管7的環形空間9在水平延伸中均勻地用熱交換器管10填充，使得在流動面積上的流動阻力係恆定的，該等管被均勻地流動並且不產生死區域或較佳的通道。熱交換器10和引導管7構成一功能單元，該功能單元如此深地安排在反應器1中，由此該最小液位允許以降低的容量實現該方法的最高的靈活性。然而引導管7的和熱交換器10的下邊緣應當僅位於如下深度，即該熔體流在從引導管7出來的出口與進入熱交換器10的入口之間的壓力損失最高為在該熱交換器中的壓力損失的10%。其他情況下，要考慮到反應器壁附近的傳熱面積的較差的環流以及對應地減小的熱傳遞。 The annular space 9 surrounding the guide tube 7 is uniformly filled with the heat exchanger tubes 10 in a horizontal extension such that the flow resistance on the flow area is constant, the tubes are uniformly flowed and no dead zone is produced or preferred aisle. The heat exchanger 10 and the guide tube 7 form a functional unit which is arranged deep in the reactor 1 so that this minimum level allows the highest flexibility of the method to be achieved with reduced capacity. However, the lower edge of the guide tube 7 and the heat exchanger 10 should only be located at a depth where the pressure loss of the melt stream between the outlet from the guide tube 7 and the inlet entering the heat exchanger 10 is at that heat. 10% of the pressure loss in the exchanger. In other cases, a poor circulation of the heat transfer area near the reactor wall and a correspondingly reduced heat transfer are taken into account.

熱交換器10的管記錄器(Rohrregister)可以由一水平安排的 蛇管束組成，其中該熔體圍繞該等管流動、該熱載體藉由該等管流動。記錄器還可以由豎直安排的管組成，其中該熱載體在該等管中流動並且熔體在該等管周圍引導。 The tube recorder (Rohrregister) of the heat exchanger 10 can be arranged by a level A coil bundle composition, wherein the melt flows around the tubes, and the heat carrier flows through the tubes. The recorder may also consist of vertically arranged tubes in which the heat carriers flow and the melt is guided around the tubes.

作為其他的可能性，可以將根據機器人蒸發器技術的由產物流過的、豎直的、內部的管安排在兩個管底部之間，該等管底部在下方和上方與該中央的引導管齊平地終止(在圖3至5中展示)。於是在該空間中，熱載體圍繞該等管流動。這個變體的一特定的實施方式在於，該等平行的管在其末端處卷邊成六角形，使得該六角形的末端無空隙地彼此插接並且彼此焊接，從而節省了一管底部。這種安排的優點在於，該熔體流抵抗在存儲面處橫向於流動方向的最小值，使得壓力損失很小並且不會出現具有死區域的阻滯。 As a further possibility, a vertical, inner tube, through which the product flows according to the robotic evaporator technique, can be arranged between the bottoms of the two tubes, the bottom of which is below and above the central guide tube Terminating flush (shown in Figures 3 to 5). The heat carrier then flows around the tubes in this space. A particular embodiment of this variant consists in that the parallel tubes are crimped at their ends into a hexagon such that the ends of the hexagons are plugged into each other without gaps and welded to each other, thereby saving the bottom of one tube. The advantage of this arrangement is that the melt flow resists a minimum transverse to the flow direction at the storage face, so that the pressure loss is small and there is no blockage with dead zones.

引導管攪拌器5能夠建立至少100mbar的壓力，以便以高旋轉速率通過安裝的熱交換器輸送在反應器1中包含的熔體體積。旋轉速率為反應器額定通過量的至少10倍、較佳的是至少30倍。 The pilot tube agitator 5 is capable of establishing a pressure of at least 100 mbar to deliver the melt volume contained in the reactor 1 through the installed heat exchanger at a high rate of rotation. The rate of rotation is at least 10 times, preferably at least 30 times, the nominal throughput of the reactor.

在相同的轉速下，引導管直徑與釜直徑相比越大、攪拌器的面積和斜率越大且攪拌器與引導管之間的間隙越緊，則在引導管7中攪拌器5的壓力累計和輸送效果就越好。當攪拌器直徑與引導管7的內直徑的比率為0.95至0.98時，實現了在引導管7中攪拌器5的良好的輸送效果。熱交換器在引導管7周圍的安排和熱交換器10在所有工作狀態下必須低於反應器1中的液位的這個條件限制了在構造上可能的傳熱面積。為了在這個空間中實施所需的傳熱面積，已經證明有用的是0.2至0.6、較佳的是0.3至0.5的引導管直徑與反應器直徑d’/d的比率。 At the same rotational speed, the larger the diameter of the guide tube compared to the diameter of the kettle, the larger the area and slope of the agitator and the tighter the gap between the agitator and the guide tube, the cumulative pressure of the agitator 5 in the guide tube 7. And the better the delivery effect. When the ratio of the diameter of the agitator to the inner diameter of the guide tube 7 is 0.95 to 0.98, a good conveying effect of the agitator 5 in the guide tube 7 is achieved. The arrangement of the heat exchanger around the guide tube 7 and the condition that the heat exchanger 10 must be lower than the liquid level in the reactor 1 under all operating conditions limits the possible heat transfer area in construction. In order to carry out the required heat transfer area in this space, it has proven useful to have a ratio of the guide tube diameter to the reactor diameter d'/d of from 0.2 to 0.6, preferably from 0.3 to 0.5.

如果反應器1中的液位在最小時處於直至約對應於反應器1的 內直徑d的高度(從引導管的上邊緣開始測量)，在引導管7中安排的攪拌器5足以設定一軸向流動。如果液位在其上，則需要一個或多個另外的攪拌器5’，該等攪拌器安排在引導管7上方。引導管攪拌器5單獨的攪拌效果可能無法達到熔體的表面，因為該熔體必須先克服該熱交換器的流動阻力。 If the liquid level in the reactor 1 is at a minimum, it is up to approximately corresponding to the reactor 1 The height of the inner diameter d (measured from the upper edge of the guide tube), the agitator 5 arranged in the guide tube 7 is sufficient to set an axial flow. If the liquid level is on it, one or more additional stirrers 5' are required, which are arranged above the guide tube 7. The separate agitation effect of the guide tube agitator 5 may not reach the surface of the melt because the melt must first overcome the flow resistance of the heat exchanger.

在其上安排的這個或該等攪拌器5’具有與引導管攪拌器不同的效果：該攪拌器要求在反應器壁附近的軸向流動以及同時在相反方向上在繞反應器軸線的中央區域中的軸向流動。這較佳的是可以是根據圖1的間斷式線圈(SEBA®攪拌器)或者連續線圈，相應地具有對反應器壁的緊密間距。也可以是具有大斜率的觸壁型翼部(wandgängigen Flügeln)的帶式攪拌器，其長度遮蓋釜周長的一半(Paravisc攪拌器，在圖2中展示)。適合於在引導管上方使用的其他的攪拌器類型係MIG®-、InterMIG®、Alpha-和Sigma-攪拌器，該等攪拌器全都在軸向上輸送、是觸壁型的並且具有在壁附近和軸線附近的相反方向的輸送效果。這個額外的攪拌元件5’的旋轉直徑z與反應器1的內直徑d的比率(z/d)在所有情況下為0.7與0.98之間。 The agitator 5' arranged thereon has a different effect than the guide tube agitator: the agitator requires axial flow near the reactor wall and at the same time in the opposite direction in the central region around the reactor axis Axial flow in the middle. This preferably can be a discontinuous coil (SEBA® stirrer) or a continuous coil according to Fig. 1, correspondingly having a close spacing to the reactor wall. It can also be a belt agitator with a large slope of the wall-type wing (wandgängigen Flügeln), the length of which covers half of the circumference of the kettle (Paravisc mixer, shown in Figure 2). Other types of mixers suitable for use above the guide tubes are MIG®-, InterMIG®, Alpha- and Sigma-mixers, all of which are transported in the axial direction, are wall-mounted and have near the wall and The conveying effect in the opposite direction near the axis. The ratio (z/d) of the rotational diameter z of this additional stirring element 5' to the inner diameter d of the reactor 1 is in each case between 0.7 and 0.98.

間斷式線圈或連續式線圈的翼部的傾斜度被選擇為，在壁附近實現向上的輸送效果。在容器軸線或攪拌器軸6附近，該流動向下指向。為此目的，在該軸或在該攪拌器臂處靠近攪拌器軸安置軸向向下輸送的元件，如傾斜葉片(槳葉元件、Viscoprop元件、Interprop元件)。在攪拌器軸附近向下指向的流動阻止了隨著降低的物料交換產生的繞該旋轉軸的循環區域(拖拽效應)。當壁附近的輸送元件施加了足夠大的軸向拉拽作用時還可以省去軸附近的輸送元件，使得在中央向下指向的流動單獨地由質量守恆而產生。另外，向下輸送的引導管攪拌器5支持藉由其抽吸作用導致的中央的向下游流動。 The inclination of the wings of the discontinuous coil or the continuous coil is selected to achieve an upward conveying effect near the wall. This flow is directed downwards near the container axis or the agitator shaft 6. For this purpose, elements that are transported axially downwards, such as inclined blades (blade elements, Viscoprop elements, Interprop elements), are placed at the shaft or at the agitator arm near the agitator shaft. The downwardly directed flow near the agitator shaft prevents the circulation area (drag effect) around the axis of rotation as a result of reduced material exchange. It is also possible to dispense with the conveying element in the vicinity of the shaft when the conveying element near the wall exerts a sufficiently large axial pulling action, so that the downwardly directed flow in the center is produced solely by mass conservation. In addition, the downwardly directed guide tube agitator 5 supports a central downstream flow caused by its suction action.

在加熱時，由於密度差異，熱交換器中自然的對流支持攪拌器5’的在壁附近向上指向的效果。該流動的方向也可以藉由反轉攪拌器5和5’的旋轉方向來交換，也就是在引導管7中且在反應器軸線附近向上，在反應器壁2附近和在熱交換器中向下，由此在冷卻該熔體時支持實現自然的對流。在此反應器1中的流動僅在方向上變化，而流動圖形基本上不變。由於在熔體中很小的溫度差異和密度差異並且因為在反應過程中沒有造成沸騰和氣泡的上升，當攪拌器5和5’的旋轉方向在加熱和冷卻時保持相同時沒有產生缺點。 When heated, the natural convection in the heat exchanger supports the effect of the agitator 5' pointing upwards near the wall due to the difference in density. The direction of the flow can also be exchanged by reversing the direction of rotation of the agitators 5 and 5', that is, in the guide tube 7 and in the vicinity of the reactor axis, near the reactor wall 2 and in the heat exchanger. Underneath, thereby supporting natural convection while cooling the melt. The flow in this reactor 1 varies only in the direction, while the flow pattern is substantially unchanged. Due to the small difference in temperature and density in the melt and because no boiling and bubble rise were caused during the reaction, no disadvantages were produced when the directions of rotation of the agitators 5 and 5' remained the same when heated and cooled.

自然地，觸壁型攪拌器在此處的黏度範圍內僅允許直至約3m/s的較低的圓周速度，由此使傳動扭矩和攪拌器驅動功率保持在極限內。在引導管中工作的攪拌器類型5大多數情況下需要更高的圓周速度，即5-15m/s，才能實現所需的輸送效果。由此產生對於觸壁型攪拌器而言8/min(例如Paravsic，圖2)的轉速差和對於引導管攪拌器而言100-200/min的轉速差。具有相對應的攪拌器驅動器的共軸的軸能夠實現安排在引導管7中的攪拌器5和安排在其上的攪拌器5’的不同旋轉速度，使其軸向輸送作用能夠彼此匹配。由此可以藉由簡單的轉速匹配來阻止軸向流動的偏離、尤其在反應器1中的循環區域。循環區域形成了一種危險，因為它們與反應器1中其餘的液體體積處於降低的交換作用中並且因而阻止了最優的混合。當反應器1應在非常不同的轉化率和因此非常不同的產物黏度下工作時，共軸驅動器係特別有利的。 Naturally, the wall-type agitator only allows a lower circumferential speed of up to about 3 m/s within the viscosity range here, thereby keeping the transmission torque and the agitator drive power within limits. The agitator type 5 operating in the guide tube requires a higher peripheral speed, i.e. 5-15 m/s, in most cases to achieve the desired conveying effect. This results in a difference in rotational speed of 8/min (eg Paravsic, FIG. 2) for the touch-port type agitator and a rotational speed difference of 100-200/min for the guide tube agitator. The coaxial shaft having the corresponding agitator drive enables the different rotational speeds of the agitator 5 arranged in the guide tube 7 and the agitator 5' arranged thereon so that the axial conveying action can match each other. This makes it possible to prevent the deviation of the axial flow, in particular the circulation area in the reactor 1, by simple speed matching. The circulation zones pose a danger because they are in a reduced exchange with the remaining liquid volume in the reactor 1 and thus prevent optimal mixing. Coaxial drives are particularly advantageous when the reactor 1 should be operated at very different conversion rates and therefore very different product viscosities.

當對於引導管攪拌器5和安排在其上的觸壁型攪拌器5’可以找到重疊的轉速範圍時，可以省去高耗費的共軸攪拌器。當引導管7中使用具有在低轉速下的高輸送作用的攪拌器5時，這尤其在更高的黏度範圍內達到。螺旋攪拌器或具有大面積葉片的卡普蘭攪拌器(兩者都具有較大的傾斜和較強的輸 送作用)可以用與安排在其上的觸壁型攪拌器5’相同的轉速來工作。例如，對於在引導管中的螺絲攪拌器和在引導管上方的SEBA®攪拌器的組合而言，適合的轉速區域係10至25/min。這對於50Pa．s的黏度和具有圖1尺寸的釜是適用的。在相同的轉速下，螺旋(具有傾斜度和在其與引導管7之間的間隙的測量值)的輸送作用可以與安排在其上的觸壁型攪拌器5’的輸送作用相匹配。觸壁型攪拌器5’的轉速可以藉由輸送元件的傾斜度、其面積以及其壁間距來匹配。 When an overlapping range of rotational speeds can be found for the guide tube agitator 5 and the wall-type agitator 5' arranged thereon, a costly coaxial agitator can be dispensed with. This is achieved in particular in the higher viscosity range when the agitator 5 with a high transport effect at low rotational speeds is used in the guide tube 7. Spiral mixer or Kaplan mixer with large area blades (both have large inclination and strong input) The action can be operated at the same rotational speed as the touch wall type agitator 5' arranged thereon. For example, for a combination of a screw agitator in the guide tube and a SEBA® agitator above the guide tube, a suitable speed range is 10 to 25/min. This is for 50Pa. The viscosity of s and the kettle having the dimensions of Figure 1 are suitable. At the same rotational speed, the conveying action of the helix (having a measurement of the inclination and the gap between it and the guide tube 7) can be matched with the conveying action of the contact wall type agitator 5' arranged thereon. The rotational speed of the wall-type agitator 5' can be matched by the inclination of the conveying element, its area and its wall spacing.

沒有共軸驅動器的其他的解決方案在於兩個或更多個攪拌器，該等攪拌器在一共同的軸上安排在一引導管7或多個引導管7、7’中或者安排在一突出部7”中(圖3、4、5)。在此，安排在最深處的攪拌器承擔將反應內容物藉由所安裝的熱交換器強制輸送的任務。安排在其上的攪拌器5’將在反應器1的中央區域中的熔體向下輸送。取消了壁附近的攪拌器元件，由此還取消了在這個區域中熔體的輸送。 A further solution without a coaxial drive consists in two or more agitators arranged in a common shaft in a guide tube 7 or a plurality of guide tubes 7, 7' or arranged in a projection In the section 7" (Figs. 3, 4, 5). Here, the agitator arranged at the deepest portion undertakes the task of forcibly conveying the reaction contents by the installed heat exchanger. The agitator 5' arranged thereon The melt in the central region of the reactor 1 is transported downwards. The agitator element near the wall is eliminated, thereby also eliminating the transport of the melt in this region.

該等解決方案造成了很小的投資成本、較低的傳動轉矩和驅動功率。然而混合作用係受限的。 These solutions result in low investment costs, low transmission torque and drive power. However, the mixing effect is limited.

在圖3中示出了一變體。藉由安排在最朝下的引導管攪拌器5，具有相同尺寸的兩個另外的攪拌器5’在沒有引導管的情況下固定在同一個軸上。在沒有引導管的情況下，該等攪拌器不僅軸向向下而且還徑向向外輸送熔體。在熱交換器上方的循環係在反應器中具有兩個或三個區域的結果，該等區域處於減小的互相的物料交換和與所有反應器內容物的物料交換。 A variant is shown in FIG. By arranging the lowermost guide tube agitator 5, two additional agitators 5' of the same size are fixed on the same shaft without the guide tube. In the absence of a guide tube, the agitators deliver the melt not only axially downward but also radially outward. The circulation above the heat exchanger is the result of having two or three zones in the reactor, which are in reduced mutual material exchange and material exchange with all reactor contents.

在這種安排的另一個變體中將一自身的引導管7’用於兩個安排在該軸上的攪拌器(圖4)。當液體液位低於安排在其上的引導管7’時，在引導管7與7’之間的間距允許從外部流入下部的引導管7中。上部的引導管攪拌器5’ 只有在該釜中的液位超過引導管7’時才啟動。相對於圖3改善了該流動的軸向取向並因此改善了混合作用。但在這兩個引導管7和7’之間的中間空間內仍然總是存在徑向的流動分量且因此存在循環。 In another variation of this arrangement a self-guide tube 7' is used for two agitators arranged on the shaft (Fig. 4). When the liquid level is lower than the guide tube 7' arranged thereon, the spacing between the guide tubes 7 and 7' allows the flow into the lower guide tube 7 from the outside. Upper guide tube agitator 5' It is only activated when the liquid level in the kettle exceeds the guide tube 7'. The axial orientation of the flow is improved relative to Figure 3 and thus the mixing effect is improved. However, there is always a radial flow component in the intermediate space between the two guide tubes 7 and 7' and therefore there is a circulation.

在這個解決方案的最後一個變體中，三個安排在同一個軸上的攪拌器5和5’在一共同的長形的引導管7中工作，該引導管具有一突出部7”。引導管7於在熱交換器上方延伸的突出部7”的區域中作為孔板在下方由全鋼板實施(圖5)。由此在釜中的直至最小液位的每種液位下保證將熔體從外部流入引導管7中。同時熱交換器10保持完全由熔體遮蓋。徑向流動相對於圖4減小，這進一步改善了混合作用。 In a final variant of this solution, three agitators 5 and 5' arranged on the same shaft work in a common elongate guide tube 7, which has a projection 7". The tube 7 is implemented as an orifice plate in the region of the projection 7" extending above the heat exchanger by a full steel plate (Fig. 5). This ensures that the melt flows from the outside into the guide tube 7 at each level in the tank up to the minimum level. At the same time the heat exchanger 10 remains completely covered by the melt. The radial flow is reduced relative to Figure 4, which further improves the mixing effect.

在攪拌釜反應器1中丙交酯的ROP中，轉化率根據本發明被限制為，使反應器中的反應產物的黏度處於約1-100Pa．s、較佳的是5-50Pa．s的範圍內。在這個黏度範圍內，本發明的引導管攪拌器用非常主導的軸向流動引導產生了黏性的反應器內容物的最優混合。這種流動引導造成旋轉的圓環的流動圖形，該圓環集合了全部的液態的反應器內容物。避免產生徑向流動分量的攪拌器，因為它們導致具有受限的物料交換的循環區域。 In the ROP of lactide in stirred tank reactor 1, the conversion is limited according to the invention, such that the viscosity of the reaction product in the reactor is between about 1 and 100 Pa. s, preferably 5-50Pa. Within the scope of s. Within this viscosity range, the guide tube agitator of the present invention produces an optimal mixing of viscous reactor contents with very predominant axial flow guidance. This flow directs the flow pattern of the rotating ring that collects all of the liquid reactor contents. Agitators that create radial flow components are avoided because they result in a circulating area with limited material exchange.

根據本發明，為了設定在攪拌釜反應器1中的較佳的黏度範圍，利用反應溫度、催化劑、引發劑和抑制劑的類型和濃度。該等參數根據本發明同時用於改變在25%與100%的額定容量範圍內的反應器容量。 In accordance with the present invention, in order to set a preferred viscosity range in the stirred tank reactor 1, the type and concentration of the reaction temperature, catalyst, initiator and inhibitor are utilized. These parameters are also used according to the invention to vary the reactor capacity in the range of 25% and 100% of the rated capacity.

在攪拌釜反應器1中的ROP的反應速度主要取決於溫度和催化劑濃度。為了保持在所提及的黏度範圍內，更是為了使在這個範圍內的黏度保持恆定，限制了丙交酯轉化率並將其保持恆定。這係如下完成的：反應溫度較佳的是保持在130℃至170℃的範圍內。藉由溫度和丙交酯流入造成的產物中相當 遲緩的溫度調節藉由快速生效的熱量送入和送出借助於內部的熱交換器得以補充。一最優化的、調節過程上的電路採用送入溫度和送入通過流量以及熱交換器溫度和熱交換器通過流量的設定變數與產物溫度作為調節變數。 The reaction rate of ROP in the stirred tank reactor 1 depends mainly on the temperature and the catalyst concentration. In order to remain within the viscosity range mentioned, and more to keep the viscosity within this range constant, the lactide conversion is limited and kept constant. This is done as follows: the reaction temperature is preferably maintained in the range of 130 ° C to 170 ° C. Equivalent to the product caused by temperature and lactide influx The slow temperature adjustment is supplemented by the fast-acting heat feed and delivery by means of an internal heat exchanger. An optimized circuit for the regulation process uses the set temperature and the feed temperature and the heat exchanger temperature and the heat exchanger through flow set variables and product temperature as the adjustment variables.

在此適合作為催化劑的是在先前技術中用於PLA的所有已知的催化劑，例如錫的有機化合物，較佳的是氧化態+2，如乙基己酸錫。其他的實例係鋅、鈦和鋯的有機化合物。如果使用有機錫化合物，則催化劑濃度在10ppm Sn與100ppm之間、較佳的是20ppm至60ppm。濃度數值在此相對於相應催化劑的金屬含量。催化劑的類型也可以影響反應速度。二價錫的有機化合物產生最高的反應速度，而用鋯的和鈦的化合物以及用四價錫的化合物獲得了大幅度降低的速度。 Suitable as catalysts here are all known catalysts for use in PLA in the prior art, such as tin organic compounds, preferably in the oxidation state +2, such as tin ethylhexanoate. Other examples are organic compounds of zinc, titanium and zirconium. If an organotin compound is used, the catalyst concentration is between 10 ppm Sn and 100 ppm, preferably 20 ppm to 60 ppm. The concentration values are here relative to the metal content of the respective catalyst. The type of catalyst can also affect the rate of reaction. The organic compound of divalent tin produces the highest reaction rate, while the compound of zirconium and titanium and the compound of tetravalent tin achieve a greatly reduced rate.

為了限制在聚合結束時首先在後續的管式反應器中實現的莫耳質量，需要投料引發劑。此處在先前技術中已知的所有引發劑都適合，例如高沸點的醇類，如己醇、辛醇、十二醇，和二醇類，如乙二醇、丙二醇、丁二醇。當應實現最終產物的長鏈支化時，例如為了提高在加工時的熔體黏度，甘油係合適的。濃度依賴於所希望的最終產物的莫耳質量和濃度並且處於0與30mmol/kg之間的範圍內。所有引發劑隨著增大的濃度而加速丙交酯的ROP反應。 In order to limit the molar mass that is first achieved in the subsequent tubular reactor at the end of the polymerization, it is necessary to feed the initiator. All initiators known in the prior art are suitable, for example high boiling alcohols such as hexanol, octanol, dodecanol, and glycols such as ethylene glycol, propylene glycol, butylene glycol. Glycerin is suitable when long chain branching of the final product should be achieved, for example to increase melt viscosity during processing. The concentration is dependent on the molar mass and concentration of the desired end product and is in the range between 0 and 30 mmol/kg. All initiators accelerate the ROP reaction of lactide with increasing concentrations.

此外ROP的反應速度還依賴於丙交酯中的羧基的濃度。其中包括PLA的所有直鏈的寡聚體，主要是乳醯乳酸(直鏈二聚體)。乳醯乳酸藉由丙交酯在痕量水作用下的開環已經在製造丙交酯時產生、在適當時還藉由在儲存和運輸丙交酯的過程中濕氣的作用產生。高的羧基濃度減緩該反應，使得在攪拌釜中ROP時需要更長的停留時間來實現預定的轉化率。在與反應器1相連的、不允許停留時間變化的管式反應器中，在特定的數值之後，轉化率和莫耳質量可 以保持。為了製造在過程上更可應用的PLA，羧基的濃度不允許超過30mmol/kg。具有Mw>150000g/mol的高莫耳質量的PLA要求<15mmol/kg的羧基濃度。過程上重要的莫耳質量的範圍在120000與250000g/mol的Mw之間。 Furthermore, the rate of reaction of ROP is also dependent on the concentration of carboxyl groups in the lactide. These include all linear oligomers of PLA, mainly chylolactic acid (linear dimer). The ring opening of chylolactic acid by lactide under the action of traces of water has been produced during the manufacture of lactide and, where appropriate, by the action of moisture during the storage and transport of lactide. A high carboxyl concentration slows the reaction so that a longer residence time is required to achieve a predetermined conversion when ROP is in the stirred tank. In a tubular reactor connected to reactor 1 that does not allow for a change in residence time, after a specific value, the conversion and molar mass can be To keep. In order to produce a PLA that is more applicable in the process, the concentration of the carboxyl group is not allowed to exceed 30 mmol/kg. A PLA having a high molar mass of Mw > 150000 g/mol requires a carboxyl group concentration of <15 mmol/kg. The process-important molar mass ranges between 120,000 and 250,000 g/mol of Mw.

在工業運行中，攪拌釜反應器1必須應對丙交酯中浮動的羧基濃度。從約15mmol/kg起的羧基需要相對於聚合結束如此長的停留時間(首先在攪拌釜反應器之外實現)，使得不再能夠製造過程上重要的莫耳質量的整個譜。因此，根據本發明在攪拌釜反應器1中的ROP中的停留時間被限制到最大4h，但較佳的是2h，使得過程上重要的產物譜能夠用最多15mmol/kg、較佳的是最多10mmol/kg的羧基濃度來獲得。 In industrial operation, the stirred tank reactor 1 must cope with the concentration of carboxyl groups floating in the lactide. The carboxyl group starting from about 15 mmol/kg requires such a long residence time relative to the end of the polymerization (first realized outside the stirred tank reactor), so that the entire spectrum of the molar mass that is important in the process can no longer be produced. Thus, the residence time in the ROP in the stirred tank reactor 1 according to the invention is limited to a maximum of 4 h, but preferably 2 h, so that a process-critical product spectrum can be used up to 15 mmol/kg, preferably at most It was obtained by a carboxyl group concentration of 10 mmol/kg.

然而，具有這個停留時間的反應器1的設計造成在具有非常低的約0至3mmol/kg的羧基濃度的丙交酯的情況下的問題。這導致非常高的反應速度。2h的停留時間本身對於這種丙交酯過高，使得不能將轉化率和因此產物黏度保持在較佳的範圍內。根據本發明，在此情況下添加降低反應速度的抑制劑。一般的羧酸適合於此。水同樣是適合的，因為它在處理溫度下與丙交酯非常快速地反應成乳醯乳酸，該乳醯乳酸自身作為抑制劑起作用。較佳的是使用具有在80與100%之間濃度的乳酸作為抑制劑。投料如下進行，使得丙交酯的羧基濃度計算為在5與15mmol/kg之間、較佳的是在5與10mmol/kg之間。 However, the design of reactor 1 with this residence time causes problems in the case of lactide having a very low carboxyl concentration of about 0 to 3 mmol/kg. This results in a very high reaction rate. The residence time of 2 h itself is too high for this lactide so that the conversion and thus the product viscosity cannot be kept within the preferred range. According to the invention, an inhibitor which reduces the reaction rate is added in this case. A typical carboxylic acid is suitable for this. Water is also suitable because it reacts very rapidly with lactide to lactide lactic acid at the processing temperature, which acts as an inhibitor itself. It is preferred to use lactic acid having a concentration between 80 and 100% as an inhibitor. The feeding is carried out as follows so that the carboxyl group concentration of lactide is calculated to be between 5 and 15 mmol/kg, preferably between 5 and 10 mmol/kg.

分析方法：Analytical method:

確定PLA預聚物中的丙交酯轉化率：Determine the lactide conversion in the PLA prepolymer:

將必須包含多於10%丙交酯的樣品溶解在氯仿中並且用凝膠滲透色譜法分析。使用PVD柱，用氯仿作為流動相。UV-可見檢測器測定在柱上分 離的物質。樣品的丙交酯含量借助於外部校準從與丙交酯相關的峰面積進行計算。 A sample containing more than 10% lactide was dissolved in chloroform and analyzed by gel permeation chromatography. A PVD column was used with chloroform as the mobile phase. UV-visible detector measurement on the column Separated matter. The lactide content of the sample was calculated from the peak area associated with lactide by means of external calibration.

確定丙交酯中的羧基：Determine the carboxyl group in the lactide:

將丙交酯溶解在甲醇中。將溶液用0.1n苯甲醇的KOH-溶液滴定。終點用電位計法測定。結果以mmol/kg表示。 The lactide was dissolved in methanol. The solution was titrated with a 0.1 n benzyl alcohol in KOH-solution. The end point was measured by a potentiometer method. The results are expressed in mmol/kg.

確定反應混合物中的羧基：Determine the carboxyl group in the reaction mixture:

將反應混合物的樣品溶解在二氯甲烷中，並且用0.1n苯甲醇的KOH-溶液針對作為指示劑的四溴酚藍進行滴定。結果以mmol/kg表示。 A sample of the reaction mixture was dissolved in dichloromethane, and titrated with tetrabromophenol blue as an indicator with a KOH-solution of 0.1 n benzyl alcohol. The results are expressed in mmol/kg.

測量在攪拌釜反應器中熔體的動態黏度：The dynamic viscosity of the melt in the stirred tank reactor was measured:

反應器中的熔體黏度依賴於轉化率和溫度。在此熔體黏度用過程黏度計測量，其感測器安排在該攪拌釜反應器中或之後的適當位置。前提條件係，在反應器中的混合係充分的，使得不出現測量值對反應器中的位置和停留時間的依賴性。 The melt viscosity in the reactor depends on the conversion and temperature. The melt viscosity is measured by a process viscometer whose sensors are arranged in position in or after the stirred tank reactor. The prerequisite is that the mixing in the reactor is sufficient so that no dependence of the measured values on the position and residence time in the reactor occurs.

過程黏度計直接測定在攪拌釜中熔體的黏度。取消了採樣和運輸樣品到實驗室中以及在實驗室黏度計中測量。這樣的測量係不準確的，因為反應的樣品的組成(轉化率)藉由冷卻和再加熱並且特別在實驗室測量過程中變化。此外，測量值易受時間上顯著延遲的影響，使得無法在此基礎上建立對反應器的調節。 The process viscometer directly measures the viscosity of the melt in the stirred tank. Samples and transport samples were removed to the laboratory and measured in a laboratory viscometer. Such measurements are inaccurate because the composition (conversion rate) of the reacted sample is varied by cooling and reheating and especially during laboratory measurements. Furthermore, the measured values are susceptible to significant time delays, making it impossible to establish adjustments to the reactor on this basis.

作為過程黏度計適合的是可商業上購得的裝置，該等裝置測量振動的感測器的能量損失或阻尼並且換算為動態黏度。該等裝置為過程調節提供了電訊號，該電訊號形成動態黏度的度量。合適的裝置的實例係Hydromotion公司的ViscoMelt 5000或者Marimex公司的Visco Scope VA 300。 Suitable as process viscometers are commercially available devices that measure the energy loss or damping of a vibrating sensor and convert it to dynamic viscosity. These devices provide electrical signals for process regulation that form a measure of dynamic viscosity. Examples of suitable devices are ViscoMelt 5000 from Hydromotion Corporation or Visco Scope VA 300 from Marimex Corporation.

實例Instance

方法： method:

實例1：具有反應器容量變化的中試規模的ROP方法 Example 1: Pilot scale ROP method with reactor capacity change

具有0.70m直徑和220kg丙交酯負載容量的攪拌釜，該攪拌釜不包含安裝的熱交換器，從外部藉由雙夾套加熱或冷卻。作為熱載體使用Therminol 66，一合成產物，該產物在環境溫度至遠高於工作溫度之間的寬廣溫度範圍內以液態存在。熱載體的溫度用安排在釜之外的電加熱/冷卻機組來設定。該釜配備有2翼的Paravisc攪拌器，該攪拌器針對旋轉平面傾斜約50°並且將產物在壁附近向上輸送。攪拌器直徑與釜的內直徑的比率為0.95。在繞攪拌器軸的中央區域中，一具有0.3m直徑和45°傾斜度的交叉葉片攪拌器支持將熔體向下輸送。轉速保持恆定在24/min。 A stirred tank having a diameter of 0.70 m and a load capacity of 220 kg of lactide, which does not contain an installed heat exchanger, heated or cooled from the outside by a double jacket. As a heat carrier, Therminol 66, a synthetic product, is present in a liquid state over a wide temperature range between ambient temperature and well above the operating temperature. The temperature of the heat carrier is set by an electric heating/cooling unit arranged outside the kettle. The kettle was equipped with a 2-wing Paravisc stirrer that was tilted about 50° against the plane of rotation and transported the product up near the wall. The ratio of the diameter of the agitator to the inner diameter of the kettle was 0.95. In the central region around the agitator shaft, a cross-blade agitator with a 0.3 m diameter and 45° inclination supports the downward transport of the melt. The speed is kept constant at 24/min.

向攪拌釜供應54kg/h丙交酯(額定容量的100%)。丙交酯包含5mmol/kg的羧基。釜中的液位被設定為，使產物在釜中的停留時間為2.0小時，即在反應器中存在108kg反應質量或95l反應體積。藉由接觸產物的約1m²的加熱面積產生了11m²/m³加熱或冷卻面積與反應體積的比率。丙交酯的送入物質流量和溫度藉由調節保持恆定。送入溫度為120℃。產物溫度借助於熱交換器的通過流量和送入溫度、藉由釜的雙夾套設定到150℃。溫度調節使這個產物溫度在靜止狀態下保持恆定到+/- 1℃。催化劑乙基己酸錫(II)如下地投料，使得在產物中存在25ppm的錫含量。引發劑十二醇設定為在丙交酯中10mmol/kg的濃度。產物在釜底部用齒輪泵抽出，使得液位保持恆定。在此排出的量為54kg/h。排出的產物的丙交酯轉化率在時間平均值中為50%。在產物的排出管道中安排的過程黏度計(Hydromotion公司的ViscoMelt 5000)顯示出15Pa．s的平均動態黏度。 The stirred tank was supplied with 54 kg/h of lactide (100% of rated capacity). The lactide contained 5 mmol/kg of a carboxyl group. The level in the kettle was set such that the residence time of the product in the kettle was 2.0 hours, i.e., 108 kg of reaction mass or 95 l of reaction volume were present in the reactor. A ratio of heating or cooling area to reaction volume of 11 m ² /m ^{3 was} produced by contacting the heated area of the product of about 1 m ² . The feed flow rate and temperature of the lactide are kept constant by adjustment. The feed temperature was 120 °C. The product temperature was set to 150 ° C by means of a double jacket of the kettle by means of the flow rate and feed temperature of the heat exchanger. Temperature regulation keeps this product temperature constant at +/- 1 °C at rest. The catalyst tin (II) ethylhexanoate was fed as follows such that a tin content of 25 ppm was present in the product. The initiator dodecanol was set to a concentration of 10 mmol/kg in lactide. The product is pumped out at the bottom of the kettle with a gear pump so that the liquid level remains constant. The amount discharged here was 54 kg/h. The lactide conversion of the discharged product was 50% in the time average. The process viscometer (Hydromotion's ViscoMelt 5000) arranged in the product discharge line showed 15Pa. The average dynamic viscosity of s.

然後，當與時間平均值偏差不超過+/- 5%時，轉化率表示為恆定。靜止狀態和時間平均值的確定要求12h，其中將所有2h的產物樣品取出並測量轉化率。 Then, when the deviation from the time average does not exceed +/- 5%, the conversion rate is expressed as constant. The determination of the quiescent state and the time average required 12 h, in which all 2 h of product samples were taken and the conversion was measured.

在釜的靜止狀態中，流入降低到額定容量(40kg/h)的74%並且將液位降低，使得平均停留時間為不變的2.0h。送入溫度和產物溫度保持得如先前所述。在設定該靜止狀態之後，測量在產物中的轉化率。轉化率為54%。用過程黏度計測量的熔體的動態黏度為20Pa．s。 In the stationary state of the kettle, the inflow was reduced to 74% of the rated capacity (40 kg/h) and the liquid level was lowered so that the average residence time was constant 2.0 h. The feed temperature and product temperature were maintained as previously described. After setting this quiescent state, the conversion in the product was measured. The conversion rate was 54%. The dynamic viscosity of the melt measured by the process viscometer is 20 Pa. s.

將送入降低到27kg/h丙交酯(額定容量的50%)。現在液位保持得如之前的情況一樣，使得平均停留時間提高到3.0h。為了平衡，借助於熱交換器來降低產物溫度。所有其餘的參數保持恆定。在若干次修正溫度之後並在設定該靜止狀態之後，在143℃下發現產物中的轉化率為52%。用過程黏度計測量的熔體的動態黏度為18Pa．s。 The feed was reduced to 27 kg/h lactide (50% of rated capacity). The liquid level is now maintained as it was before, resulting in an average residence time of 3.0 h. For equilibration, the temperature of the product is lowered by means of a heat exchanger. All remaining parameters remain constant. After several times of correction of the temperature and after setting the quiescent state, the conversion in the product was found to be 52% at 143 °C. The dynamic viscosity of the melt measured by the process viscometer is 18 Pa. s.

在重新將丙交酯的送入降低到16kg/h(額定容量的30%)之後，進一步將液位保持恆定，使得停留時間提高到5.0h。除了降低產物溫度到137℃，現在還將催化劑濃度減少到22ppm。在設定該靜止狀態之後，轉化率為51%。用過程黏度計測量的熔體的動態黏度為16Pa．s。 After re-feeding the lactide to 16 kg/h (30% of rated capacity), the liquid level was further kept constant, so that the residence time was increased to 5.0 h. In addition to lowering the product temperature to 137 ° C, the catalyst concentration is now reduced to 22 ppm. After setting this quiescent state, the conversion rate was 51%. The dynamic viscosity of the melt measured by the process viscometer is 16 Pa. s.

實例2：具有反應器容量變化的生產規模的ROP方法 Example 2: Production scale ROP method with reactor capacity change

一具有18t丙交酯的負載容量的連續工作的攪拌釜具有2.30m的內直徑。該攪拌釜根據圖1配備有在引導管中的內部的熱交換器、螺絲攪拌器和在該引導管上方的SEBA®攪拌器。對於熱交換必需的174m²的面積用由蛇管組成的束來提供，該束安排在攪拌器的引導管周圍。與中試規模一樣，加熱或冷卻面積與反應器體積的比率為11m²/m³。由於引導管上邊緣和管束總是要保持在液 體液位之下的要求，在2.0h的停留時間下的容量不能低於50%。液態熱載體的溫度在釜之外的用於加熱和冷卻的設備中設定並且接著藉由安排在釜中的熱交換器來泵送。釜的雙夾套藉由相同的熱載體保持在與該熱交換器相同的溫度上。 A continuously operating stirred tank having a loading capacity of 18 t of lactide has an inner diameter of 2.30 m. The stirred tank is equipped according to Figure 1 with an internal heat exchanger in the guide tube, a screw stirrer and an SEBA® stirrer above the guide tube. The area of 174 m ² necessary for heat exchange is provided by a bundle consisting of a coil arranged around the guide tube of the agitator. As with the pilot scale, the ratio of heating or cooling area to reactor volume was 11 m ² /m ³ . Since the upper edge of the guide tube and the bundle of tubes are always kept below the liquid level, the capacity at a residence time of 2.0 h must not be less than 50%. The temperature of the liquid heat carrier is set in the apparatus for heating and cooling outside the kettle and is then pumped by a heat exchanger arranged in the kettle. The double jacket of the kettle is maintained at the same temperature as the heat exchanger by the same heat carrier.

將9000kg/h丙交酯作為額定容量借助於準確投料的齒輪泵供應給該釜。丙交酯具有5mmol/kg的羧基含量。丙交酯的送入溫度用連接在釜上游的熱交換器調節到130℃。一最優化的調節過程的電路將產物溫度保持在150℃，藉由在送入溫度下以及在用於所安裝的熱交換器的熱載體的溫度下的調節性干預。 9000 kg/h of lactide was supplied to the kettle as a rated capacity by means of an accurately fed gear pump. Lactide has a carboxyl group content of 5 mmol/kg. The feed temperature of the lactide was adjusted to 130 ° C with a heat exchanger connected upstream of the kettle. An optimized conditioning circuit maintains the product temperature at 150 ° C by means of a regulatory intervention at the feed temperature and at the temperature of the heat carrier for the installed heat exchanger.

作為催化劑將乙基己酸錫(II)並且作為引發劑將十二醇用投料泵連續供應給該釜，使得產物中的催化劑濃度為25ppm Sn且引發劑濃度為10mmol/kg。 As a catalyst, tin (II) ethylhexanoate was used as an initiator to continuously supply dodecanol to the kettle with a feed pump so that the catalyst concentration in the product was 25 ppm Sn and the initiator concentration was 10 mmol/kg.

反應器中的液位調節將產物的停留時間保持在2.0h。齒輪泵負責從反應器排出產物，平均為9000kg/h。在產物中測量的丙交酯轉化率在反應器的靜止狀態中時間平均值為53%。在產物排出導管中安排有一過程黏度計Marimex公司的Visco Scope VA 300。這指示了20Pa．s的熔體平均動態黏度。 The level adjustment in the reactor maintained the residence time of the product at 2.0 h. The gear pump is responsible for discharging the product from the reactor, averaging 9000 kg/h. The lactide conversion measured in the product was 53% in the static state of the reactor. A process viscometer, Marimex's Visco Scope VA 300, is arranged in the product discharge conduit. This indicates 20Pa. The average dynamic viscosity of the melt of s.

在降低丙交酯送入到4500kg/h(額定容量的50%)時釜中的液位借助於排出泵被降低直到該停留時間如之前一樣為2.0h。產物溫度在此保持在150℃。同時隨著丙交酯的通過量降低催化劑投料和引發劑投料，使其在產物中的濃度保持相同。在新液位下實現釜中的靜止狀態之後，測量丙交酯轉化率。丙交酯轉化率的時間平均值為54%。用過程黏度計測量的熔體的動態黏度為22Pa．s。 The liquid level in the kettle was lowered by means of a discharge pump while reducing the feeding of lactide to 4500 kg/h (50% of the rated capacity) until the residence time was 2.0 h as before. The product temperature was kept here at 150 °C. At the same time, as the throughput of lactide reduces the catalyst charge and initiator charge, the concentration in the product remains the same. After achieving a standstill in the kettle at the new level, the lactide conversion was measured. The time average of the lactide conversion was 54%. The dynamic viscosity of the melt measured by the process viscometer is 22 Pa. s.

為了將反應器容量降低到2250kg/h(額定容量的25%)，保持釜中 的液位，使得停留時間提高到4.0h。溫度降低到142℃並且同時將催化劑投料降低直到在產物中的濃度為20ppm Sn。引發劑濃度保持不變。在改變後的條件下實現釜中的靜止狀態之後，測量丙交酯轉化率。丙交酯轉化率的時間平均值為52%。用過程黏度計測量的熔體的動態黏度為18Pa．s。 In order to reduce the reactor capacity to 2250kg / h (25% of the rated capacity), keep the kettle The liquid level increases the residence time to 4.0h. The temperature was lowered to 142 ° C and the catalyst charge was simultaneously reduced until the concentration in the product was 20 ppm Sn. The initiator concentration remains the same. After the quiescent state in the kettle was achieved under the changed conditions, the lactide conversion was measured. The time average of the lactide conversion was 52%. The dynamic viscosity of the melt measured by the process viscometer is 18 Pa. s.

實例3：用於丙交酯的ROP的攪拌釜反應器 Example 3: Stirred tank reactor for ROP of lactide

圖1示出一具有9000kg/h容量和18t產物的負載容量的連續運行的攪拌釜的實施方式。其內直徑為2.3m。該錐形底部具有90°的開口角度。容器蓋實施為盤形底部。該容器蓋承載具有電機和傳動器的攪拌器驅動器。軸貫穿部配備有熱隔離器，該熱隔離器用液態的熱載體工作並且阻止在非靜止的工作狀態下產物在攪拌器或軸上凝固。 Figure 1 shows an embodiment of a continuously operating stirred tank having a capacity of 9000 kg/h and a capacity of 18 t of product. Its inner diameter is 2.3m. The tapered bottom has an opening angle of 90°. The container lid is embodied as a disc-shaped bottom. The container cover carries an agitator drive with a motor and an actuator. The shaft penetration is provided with a thermal isolator that operates with a liquid heat carrier and prevents the product from solidifying on the agitator or shaft during non-stationary operation.

反應器從外部藉由雙夾套加熱，該雙夾套劃分成3個區域。蓋和在最大液位上方的容器壁以120℃的溫度加熱。在容器中最大和最小液位之間的液位下，中間區域保持為與產物溫度相同的溫度。僅當達到最小液位時，才可以設定與在蓋中相同的溫度。最下部的區域總是保持在產物溫度。 The reactor is heated from the outside by a double jacket which is divided into three zones. The lid and the wall of the vessel above the maximum liquid level were heated at a temperature of 120 °C. At the level between the maximum and minimum levels in the vessel, the intermediate zone remains at the same temperature as the product temperature. The same temperature as in the cover can be set only when the minimum level is reached. The lowermost area is always maintained at the product temperature.

用於調節產物溫度的熱交換器由水平安排的蛇管組成，液態的熱載體在該等蛇管中循環。引導管中的攪拌器向下擠壓熔體到該錐形的容器底部中，在此該熔體轉向並且從下方流到熱交換器管。蛇管在流動方向上偏置地安排(“有空隙”)，以便能夠用反應器中的熔體實現均勻流過該束。管束向上用引導管的上邊緣終止。這條水平線標記了反應器中最低的可能的填充狀態，該填充狀態一方面是必須的，以便能夠向該引導管中送入熔體並因此藉由熱交換器進行循環。另一方面，這個填充狀態係必須的，以便在藉由熔體遮蓋的情況下保持加熱面積並且阻止聚合物層的沈積。 The heat exchanger for regulating the temperature of the product consists of horizontally arranged coils in which the liquid heat carrier circulates. The agitator in the guide tube presses the melt down into the bottom of the conical vessel where it melts and flows from below to the heat exchanger tubes. The coils are arranged offset ("with gaps") in the flow direction so that a uniform flow through the bundle can be achieved with the melt in the reactor. The tube bundle is terminated upward with the upper edge of the guide tube. This horizontal line marks the lowest possible filling state in the reactor, which is necessary on the one hand in order to be able to feed the melt into the guiding tube and thus to circulate by means of a heat exchanger. On the other hand, this filling state is necessary in order to maintain the heating area and prevent the deposition of the polymer layer in the case of being covered by the melt.

使用Marlotherm FP作為熱載體，它在-10℃與+280℃之間以液態存在並且是無毒的。所需的分流的數量在該反應器之外藉由所希望的溫度和所要求的壓力和物質流量來提供並且從外部供應給反應器。熱送入藉由中壓蒸氣進行，熱送出藉由空氣冷卻進行。熱載體在封閉的循環中運行。釜中的產物溫度的調節確定了向反應器中的熱交換器的分流的溫度。 Marlotherm FP was used as a heat carrier, which was present in a liquid state between -10 ° C and +280 ° C and was non-toxic. The amount of split required is provided outside the reactor by the desired temperature and the required pressure and mass flow and is supplied externally to the reactor. The heat feed is carried out by medium pressure steam, and the heat transfer is carried out by air cooling. The heat carrier operates in a closed loop. The adjustment of the product temperature in the kettle determines the temperature of the split to the heat exchanger in the reactor.

螺旋攪拌器安排在一中央的引導管中。引導管與容器的內直徑的比率係0.33。攪拌器的直徑與引導管內直徑的比率為0.98。引導管可加熱地實施為雙夾套。在構成引導管的該等同心的管之間的間隙由液態的熱載體流過，該熱載體也饋送到熱交換器。引導管中熱載體的溫度係與熱交換器中相同的。 The spiral agitator is arranged in a central guiding tube. The ratio of the guide tube to the inner diameter of the container is 0.33. The ratio of the diameter of the agitator to the inner diameter of the guide tube was 0.98. The guide tube can be implemented thermally as a double jacket. The gap between the concentric tubes constituting the guide tube flows through the liquid heat carrier, which is also fed to the heat exchanger. The temperature of the heat carrier in the guide tube is the same as in the heat exchanger.

在最小的填充狀態中以及在不高於容器直徑(自引導管的下邊緣起測量)的填充狀態中，引導管中的攪拌器足以確保藉由該熱交換器在容器中所有熔體體積的軸向循環。 In the minimum filling state and in the filling state not higher than the diameter of the vessel (measured from the lower edge of the guiding tube), the agitator in the guiding tube is sufficient to ensure all the melt volume in the vessel by means of the heat exchanger Axial circulation.

為了在更高液位下也實現良好的混合結果，第二攪拌器安排在該引導管上方的同一個軸線上。該第二攪拌器用於直至最大液位都保持軸向的循環流動並且於是在反應器的額定通過量下也實現混合。在此使用所謂的區段帶式攪拌器(Chema公司的SEBA®攪拌器)作為攪拌器。攪拌器具有4個臂，該等臂對於製造軸向流動圖形是必需的。該等臂承載具有60mm壁間距的壁附近的平面元件，該等平面元件相對於水平傾斜30°，形狀與間斷型線圈的區段可比較。該等平面元件將在壁附近區域中的熔體向上輸送並且於是延長了軸向流動，該流動從熱交換器向上穿透。在攪拌器軸附近，攪拌器壁承載具有傾斜葉片攪拌器形狀的平面元件。該等平面元件具有與在壁附近相反的傾斜並且向下施加輸送作用。該等平面元件阻止了在攪拌器軸周圍形成旋轉的、不良混合的熔體區域並且支持在引導管中向螺旋攪拌器的熔體送入。 In order to achieve good mixing results at higher levels, the second agitator is arranged on the same axis above the guide tube. This second agitator is used to maintain axial circulating flow up to the maximum liquid level and thus also achieve mixing at the nominal throughput of the reactor. A so-called zone belt agitator (Chema's SEBA® mixer) is used here as a stirrer. The agitator has 4 arms that are necessary to create an axial flow pattern. The arms carry planar elements near the wall having a 60 mm wall spacing that are inclined 30[deg.] with respect to the horizontal and are comparable in shape to the sections of the discontinuous coil. The planar elements transport the melt up in the vicinity of the wall and thus prolong the axial flow which penetrates upwards from the heat exchanger. Near the agitator shaft, the agitator wall carries a planar element having the shape of a slanted blade agitator. The planar elements have an opposite slope to the vicinity of the wall and apply a downward transport. The planar elements prevent the formation of a rotating, poorly mixed melt zone around the agitator shaft and support the feed of the melt into the spiral agitator in the guide tube.

這兩種攪拌器類型固定在同一個軸上並且可以在15與25/min之間的轉速範圍內工作。驅動功率在22/min下為59kW，傳動轉矩為6500Nm。在額定通過量和22/min的轉速下，反應器中的旋轉速率係送入流量的46倍，這意味著2.6分鐘的混合時間。 Both types of agitators are fixed on the same shaft and can operate over a range of speeds between 15 and 25/min. The driving power is 59 kW at 22/min and the transmission torque is 6500 Nm. At rated throughput and 22/min speed, the rate of rotation in the reactor was 46 times the flow rate, which means a mixing time of 2.6 minutes.

圖2示出具有與圖1相同大小和同樣熱交換器的攪拌釜，然而具有另外的攪拌器。在引導管中，卡普蘭攪拌器用5個翼以20mm的壁間距工作。該攪拌器將熔體向下輸送，以及隨後在熔體在容器底部轉向之後，藉由該熱交換器向上輸送。引導管與容器的內直徑的比率係0.39。 Figure 2 shows a stirred tank having the same size and the same heat exchanger as Figure 1, but with an additional stirrer. In the guide tube, the Kaplan mixer was operated with 5 wings at a wall spacing of 20 mm. The agitator delivers the melt downwards and then is conveyed upwards by the heat exchanger after the melt is turned at the bottom of the vessel. The ratio of the guide tube to the inner diameter of the container is 0.39.

引導管的和熱交換器的上方安排有一觸壁型攪拌器。在此該攪拌器為具有2個翼的帶式攪拌器(Paravisc，Ekato公司)，該等翼相對於旋轉平面傾斜，使其在壁附近施加向上的輸送作用。攪拌器直徑與釜的內直徑的比率為0.95。在軸附近，相對於旋轉平面傾斜45°的傾斜葉片攪拌器類型的平面元件安置在該軸處，以便實現向下的輸送作用。這種攪拌器組合產生了與根據圖1的攪拌器類似的軸向流動圖形並且因此產生了軸向混合作用。槳葉攪拌器和錨式攪拌器需要不同的轉速。這使得共軸驅動器係必要的，其中槳葉攪拌器的轉速在100與200/min之間且錨式攪拌器在5-20/min。共軸驅動器允許這兩個攪拌器的輸送作用的良好匹配以及因此該軸向流動圖形的優化，以便避免徑向流動和循環區域。在150/min的卡普蘭攪拌器的轉速和16/min的錨式攪拌器的轉速下，旋轉速率為額定通過量的30倍，混合時間為4min。 A contact wall type agitator is arranged above the guide tube and the heat exchanger. The agitator here is a belt agitator (Paravisc, Ekato) with 2 wings which are inclined with respect to the plane of rotation, causing an upward conveying action in the vicinity of the wall. The ratio of the diameter of the agitator to the inner diameter of the kettle was 0.95. Near the shaft, a planar element of the inclined blade agitator type inclined at 45[deg.] with respect to the plane of rotation is placed at the shaft in order to achieve a downward conveying action. This agitator combination produces an axial flow pattern similar to the agitator according to Figure 1 and thus produces axial mixing. Blade agitators and anchor agitators require different speeds. This makes a coaxial drive necessary where the blade stirrer speed is between 100 and 200/min and the anchor stirrer is at 5-20/min. The coaxial drive allows for a good match of the conveying action of the two agitators and thus the optimization of the axial flow pattern in order to avoid radial flow and circulation areas. At a rotational speed of the 150/min Kaplan stirrer and a 16/min anchor stirrer, the rotation rate was 30 times the rated throughput and the mixing time was 4 min.

圖3示出一具有與圖1相同大小的本發明攪拌釜的另一個變體。該熱交換器為一由豎直的管組成的束，該等管在內部被產物流過並且在外部被熱交換器流過。該等管在下方和上方焊接到環形的管底部中，該等管底部同時分離由熱載體流過的夾套空間與產物空間並且承載該中央的引導管。如在圖1中一 樣，在此熱交換器圍繞引導管安排並且其高度對應於引導管的高度。 Figure 3 shows another variant of the stirred kettle of the invention having the same dimensions as Figure 1. The heat exchanger is a bundle of vertical tubes that are internally flowed by the product and externally passed by the heat exchanger. The tubes are welded to the bottom of the annular tube below and above, the bottoms of the tubes simultaneously separating the jacket space and product space through which the heat carrier flows and carrying the central guide tube. As shown in Figure 1 Thus, the heat exchanger is arranged around the guide tube and its height corresponds to the height of the guide tube.

在引導管中，一具有45°迎角的槳葉攪拌器(Viscopropeller，Stelzer公司)以緊密的壁間距工作。引導管直徑與釜的內直徑的比率為0.46。攪拌器的直徑與引導管內直徑的比率為0.98。該攪拌器將熔體向下輸送並且然後，熔體在容器底部轉向之後，藉由該熱交換器管向上輸送。攪拌器轉速為130/min。引導管的和熱交換器的上方安排有兩個另外的相同構造的槳葉攪拌器，該等槳葉攪拌器具有相同的直徑以及向下的輸送作用。不存在觸壁型攪拌器。軸向的混合不如根據圖1和2的攪拌釜好。混合時間為15min。 In the guide tube, a paddle stirrer (Viscopropeller, Stelzer) with an angle of attack of 45° operates at tight wall spacing. The ratio of the diameter of the guide tube to the inner diameter of the kettle was 0.46. The ratio of the diameter of the agitator to the inner diameter of the guide tube was 0.98. The agitator delivers the melt downwards and then, after the melt is turned at the bottom of the vessel, it is transported upwards by the heat exchanger tubes. The stirrer speed was 130/min. Two additional identically configured blade agitators are arranged above the guide tube and the heat exchanger, the paddle mixers having the same diameter and downward conveying action. There is no touch wall type agitator. The axial mixing is not as good as the stirred tank according to Figures 1 and 2. The mixing time is 15 min.

當根據圖4將第二攪拌器與引導管安排在該第一攪拌器上方時，混合作用更好。混合時間為12min。 When the second agitator and the guide tube are arranged above the first agitator according to Figure 4, the mixing effect is better. The mixing time is 12 min.

圖5示出具有3個在同一個軸上彼此上下安裝的槳葉攪拌器大的變體，該等槳葉攪拌器在一共同的引導管中工作。引導管在最下部的攪拌器的和熱交換器的高度上由全鋼板實施，如在先前提及的實施方式中一樣。在熱交換器上方，引導管由孔板組成。這個實施方式主要抑制了徑向的流動，該等徑向流動在上述兩個變體中出現並且不利影響混合作用。該實施方式負責在引導管之外的指向上游的流動和在引導管內的指向下游的流動，並且將這兩個流動彼此分離。同時這個實施方式允許在釜中該熱交換器上方的每個液位下從外向內朝引導管內的流入。混合時間為6min。 Figure 5 shows a large variant with three blade agitators mounted one above the other on the same shaft, the paddle mixers operating in a common guide tube. The guide tube is implemented by a full steel plate at the height of the lowermost agitator and the heat exchanger, as in the previously mentioned embodiment. Above the heat exchanger, the guide tube consists of an orifice plate. This embodiment primarily suppresses radial flow which occurs in both variants described above and adversely affects mixing. This embodiment is responsible for the flow directed upstream of the guide tube and the flow directed downstream within the guide tube and separating the two flows from each other. At the same time, this embodiment allows inflow from the outside to the inside of the guide tube at each level above the heat exchanger in the kettle. The mixing time is 6 min.

1‧‧‧反應器 1‧‧‧reactor

2‧‧‧反應器壁部 2‧‧‧Reactor wall

3‧‧‧反應器內部空間 3‧‧‧Reactor internal space

4‧‧‧出口 4‧‧‧Export

5‧‧‧攪拌元件 5‧‧‧ stirring element

5’‧‧‧攪拌元件 5'‧‧‧ stirring element

5”‧‧‧攪拌元件 5"‧‧‧ stirring elements

6‧‧‧攪拌軸 6‧‧‧Agitator shaft

7‧‧‧引導管 7‧‧‧Guide tube

8‧‧‧內部空間 8‧‧‧Internal space

9‧‧‧空間 9‧‧‧ Space

10‧‧‧熱交換器元件 10‧‧‧ heat exchanger components

I‧‧‧區域 I‧‧‧ area

II‧‧‧區域 II‧‧‧Area

III‧‧‧區域 III‧‧‧Area

h‧‧‧高度 H‧‧‧height

h’‧‧‧尺度 H’‧‧‧ scale

d‧‧‧直徑 D‧‧‧diameter

d’‧‧‧外直徑 D’‧‧‧outer diameter

V_最小‧‧‧最小填充液位 V _minimum ‧ ‧ minimum fill level

V_最大‧‧‧最大填充狀態 V _max ‧ ‧ maximum filling status

x‧‧‧內直徑 X‧‧‧ inner diameter

y‧‧‧旋轉直徑 y‧‧‧Rotary diameter

z‧‧‧尺度 Z‧‧‧ scale

Claims (19)

一種反應器(1)，包括：一反應器壁部(2)，該反應器壁部圍成一軸向延伸的圓柱形或實質上圓柱形的反應器內部空間(3)，該反應器內部空間包括一軸向的尺度(h)和一垂直於該軸向尺度測量的直徑(d)，其中該反應器內部空間(3)具有至少一個用於反應物的入口以及在反應器底部的一出口(4)，一軸向延伸的攪拌軸(6)，該攪拌軸具有至少一個軸向輸送的攪拌元件(5)，該攪拌軸在該反應器(1)的一上端通過該反應器壁部(2)引入到該反應器內部空間(3)中，其特徵在於，在該反應器內部空間(3)中安排有一軸向延伸的圓柱形或實質上圓柱形的引導管(7)，該引導管具有一軸向尺度(h’)和一垂直於該軸向尺度測量的外直徑(d’)並限定一引導管內部空間(8)，使得在該反應器壁部(2)與該引導管(7)之間形成一空間(9)，其中該引導管(7)與該反應器底部並且與該反應器內部空間(3)的上端間隔開，其中對於該引導管(7)的軸向尺度(h’)與該反應器內部空間(3)的軸向尺度(h)的比率為：(h’/h)0.9，對於該引導管(7)的外直徑(d’)與該反應器內部空間(3)的直徑(d)的比率為：(d’/d)0.9，其中該攪拌軸(6)用至少一個攪拌元件(5)延伸直到該引導管內部空間(8)中，並且在該空間(9)之內安排有一能夠由反應混合物流過的熱交換器(10)。 A reactor (1) comprising: a reactor wall portion (2) enclosing an axially extending cylindrical or substantially cylindrical reactor internal space (3) inside the reactor The space comprises an axial dimension (h) and a diameter (d) measured perpendicular to the axial dimension, wherein the reactor internal space (3) has at least one inlet for the reactants and one at the bottom of the reactor An outlet (4), an axially extending agitating shaft (6) having at least one axially conveying agitating element (5) passing through the reactor wall at an upper end of the reactor (1) Part (2) is introduced into the inner space (3) of the reactor, characterized in that an axially extending cylindrical or substantially cylindrical guiding tube (7) is arranged in the inner space (3) of the reactor, The guide tube has an axial dimension (h') and an outer diameter (d' measured perpendicular to the axial dimension and defines a guide tube interior space (8) such that at the reactor wall portion (2) A space (9) is formed between the guiding tubes (7), wherein the guiding tube (7) is connected to the bottom of the reactor and to the upper end of the internal space (3) of the reactor. Spaced apart, wherein for the guide tube (7) of the axial dimension (h ') a ratio of the inner space of the reactor (3) an axial dimension (h) of: (h' / h) 0.9, the ratio of the outer diameter (d') of the guide tube (7) to the diameter (d) of the inner space (3) of the reactor is: (d'/d) 0.9, wherein the agitating shaft (6) extends with at least one agitating element (5) into the inner space (8) of the guiding tube, and a heat exchanger capable of flowing through the reaction mixture is arranged within the space (9) (10). 如請求項1所述的反應器(1)，其中，該引導管(7)以其下端與該反應器壁部(2)以一間距(a)間隔開，使得在該具有至少一個軸向輸送的攪拌元件(5)的攪拌軸(6)工作時，作為在來自引導管(7)的出口處與向該空間(9)中的入口處的反應器混合物的壓力差來測量的該反應器混合物的壓力損失最大為作為在進入該熱交換器(10)的入口處與來自該熱交換器的出口處的反應器混合物的壓力差來測量的在流過該熱交換器(10)時該反應器混合物的壓力損失的10%，及/或在該反應器底部的投影中測量的間距(a)相對於該反應器內部空間的軸向尺度(h)為0.001a/h0.25，較佳的是0.01a/h0.2，特別較佳的是0.05a/h0.15。 The reactor (1) according to claim 1, wherein the guide tube (7) is spaced apart from the reactor wall portion (2) by a gap (a) at its lower end such that it has at least one axial direction The reaction is measured as the pressure difference between the outlet of the pilot tube (7) and the reactor mixture at the inlet in the space (9) when the agitator shaft (6) of the agitation element (5) is in operation. The pressure loss of the mixer mixture is at most as measured as the pressure difference at the inlet to the heat exchanger (10) and the reactor mixture from the outlet of the heat exchanger when flowing through the heat exchanger (10) 10% of the pressure loss of the reactor mixture, and/or the spacing measured in the projection at the bottom of the reactor (a) is 0.001 relative to the axial dimension (h) of the internal space of the reactor a/h 0.25, preferably 0.01 a/h 0.2, particularly preferably 0.05 a/h 0.15. 如請求項1~2中任一項所述之反應器(1)，其中，對於該引導管(7)的軸向尺度(h’)與該反應器內部空間(3)的軸向尺度(h)的比率為：0.05(h’/h)0.5，較佳的是0.075(h’/h)0.4，特別較佳的是0.1(h’/h)0.25，及/或對於該引導管(7)的外直徑(d’)與該反應器內部空間(3)的直徑(d)的比率為：0.2(d’/d)0.6，較佳的是0.3(d’/d)0.5。 The reactor (1) according to any one of claims 1 to 2, wherein an axial dimension (h') of the guiding tube (7) and an axial dimension of the internal space (3) of the reactor ( h) ratio is: 0.05 (h'/h) 0.5, preferably 0.075 (h'/h) 0.4, particularly preferably 0.1 (h'/h) 0.25, and/or the ratio of the outer diameter (d') of the guide tube (7) to the diameter (d) of the inner space (3) of the reactor is: 0.2 (d'/d) 0.6, preferably 0.3 (d'/d) 0.5. 如請求項1~3中任一項所述之反應器(1)，其中，該引導管內部空間(8)具有一垂直於該軸向尺度測量的內直徑(x)並且該至少一個攪拌元件(5)中的至少一者具有一垂直於該軸向尺度測量的旋轉直徑(y)，其中對於比率y/x為：0.9(y/x)0.99，較佳的是0.95(y/x)0.98。 The reactor (1) according to any one of claims 1 to 3, wherein the guide tube internal space (8) has an inner diameter (x) measured perpendicular to the axial dimension and the at least one stirring element At least one of (5) has a rotational diameter (y) measured perpendicular to the axial dimension, wherein the ratio y/x is: 0.9 (y/x) 0.99, preferably 0.95 (y/x) 0.98. 如請求項1~4中任一項所述之反應器(1)，其中，該反應器底部形成為錐形，並且該出口(4)安排在該錐形的尖端處，其中該錐形的開口角度較佳的是>50°，進一步較佳的是55°至120°，特別較佳的是60°至100°。 The reactor (1) according to any one of claims 1 to 4, wherein the bottom of the reactor is formed into a taper, and the outlet (4) is arranged at the tip end of the taper, wherein the taper The opening angle is preferably > 50°, further preferably 55° to 120°, and particularly preferably 60° to 100°. 如請求項1~5中任一項所述之反應器(1)，其中，該攪拌軸(6)在軸向方向上在該引導管(7)的上邊緣與該反應器內部空間(3)的上端之間的區域中具有至少一個另外的軸向輸送的攪拌元件(5’)，該至少一個另外的攪拌元件較佳的是設計為分成兩個部分，使得在該攪拌軸(6)工作時用該至少一個另外的軸向輸送的攪拌元件(5’)在一在軸向方向的投影中對應於該引導管內部空間(8)的區域中產生與一在該軸向方向的投影中對應於該空間(9)的區域中在軸向方向上反向的流動，或者該至少一個另外的攪拌元件較佳的是排他地形成在一在軸向方向的投影中對應於該引導管內部空間(8)的區域中，或者該至少一個另外的攪拌元件較佳的是排他地形成在一在軸向方向的投影中對應於該空間(9)的區域中。 The reactor (1) according to any one of claims 1 to 5, wherein the stirring shaft (6) is in the axial direction at the upper edge of the guiding tube (7) and the reactor internal space (3) There is at least one additional axially conveyed agitating element (5') in the region between the upper ends, which is preferably designed to be divided into two parts, such that the agitating shaft (6) In operation, the at least one further axially conveyed stirring element (5') produces a projection in the axial direction corresponding to the inner space (8) of the guide tube in a projection in the axial direction. a flow in the axial direction opposite to the space (9), or the at least one additional stirring element is preferably formed exclusively in a projection in the axial direction corresponding to the guide tube In the region of the interior space (8), or the at least one further agitating element is preferably exclusively formed in a region corresponding to the space (9) in the projection in the axial direction. 如請求項6所述之反應器(1)，其中，該至少一個另外的軸向輸送的攪拌元件(5’)具有一垂直於軸向方向延伸的尺度(z)，其中對於該尺度(z)與該反應器內部空間(3)的尺度(d)的比率為：0.7(z/d)0.99，較佳的是0.8(z/d)0.98，特別較佳的是0.9(z/d)0.98。 The reactor (1) according to claim 6, wherein the at least one further axially conveyed stirring element (5') has a dimension (z) extending perpendicular to the axial direction, wherein for the dimension (z) The ratio to the dimension (d) of the internal space (3) of the reactor is: 0.7 (z/d) 0.99, preferably 0.8 (z/d) 0.98, particularly preferably 0.9 (z/d) 0.98. 如請求項6或請求項7所述之反應器(1)，其中，該攪拌軸(6)形成為共軸的，使得該至少一個攪拌元件(5)和該至少一個另外的攪拌元件(5’)能夠不依賴於彼此而被致動。 The reactor (1) of claim 6 or claim 7, wherein the agitating shaft (6) is formed to be coaxial such that the at least one agitating element (5) and the at least one additional agitating element (5) ') can be actuated independently of each other. 如請求項1~8中任一項所述之反應器(1)，其中，該攪拌元件(5)選自由卡普蘭攪拌器，傾斜葉片攪拌器，螺旋攪拌器，槳葉攪拌器，交叉葉片攪拌器所組成的群組，及/或該至少一個另外的攪拌元件(5’，5”)選自由傾斜葉片攪拌器，交叉葉片攪拌器，帶有連續或間斷線圈的線圈攪拌器，帶式攪拌器和具有相對於旋轉平面傾斜的多個臂的錨式攪拌器所組成的群組。 The reactor (1) according to any one of claims 1 to 8, wherein the stirring element (5) is selected from the group consisting of a Kaplan mixer, a tilting blade agitator, a spiral agitator, a blade agitator, a cross blade The group of agitators, and/or the at least one additional agitating element (5', 5") is selected from the group consisting of a tilting blade agitator, a cross blade agitator, a coil agitator with continuous or intermittent coils, a belt type A group of agitators and anchor agitators having a plurality of arms inclined with respect to the plane of rotation. 如請求項1~9中任一項所述之反應器(1)，其中，在該引導管(7)的上邊緣與該反應器內部空間(3)的上端之間的區域中存在至少一個另外的引導管(7’)，及/或該引導管具有一個在軸向方向上在該反應器內部空間(3)的上端的方向上延伸的突出部(7”)，該突出部具有穿孔及/或設計為孔板。 The reactor (1) according to any one of claims 1 to 9, wherein at least one of the area between the upper edge of the guide tube (7) and the upper end of the reactor internal space (3) exists An additional guide tube (7'), and/or the guide tube has a projection (7") extending in the axial direction in the direction of the upper end of the inner space (3) of the reactor, the projection having a perforation And / or designed as an orifice plate. 如請求項1~10中任一項所述之反應器(1)，其中，該引導管(7)在該反應器內部空間(3)中在軸向方向上如下定位，使得導致該反應混合物的最小填充高度的反應混合物最小填充量在2小時的平均停留時間下小於該反應器的額定容量下的填充量的50%，在該最小填充量下該引導管(7)的上邊緣浸沒到該反應混合物中。 The reactor (1) according to any one of claims 1 to 10, wherein the guide tube (7) is positioned in the reactor internal space (3) in the axial direction as follows, such that the reaction mixture is caused The minimum fill level of the reaction mixture minimum fill amount is less than 50% of the fill capacity of the reactor at the average residence time of 2 hours, at which the upper edge of the guide tube (7) is submerged to In the reaction mixture. 如請求項1~11中任一項所述之反應器(1)，其中，該反應器壁部(2)係可調溫的，較佳的是劃分為在多個在軸向方向上安排的分開地可調溫的區域，特別較佳的是具有三個分開地可調溫的區域(I，II，III)，其中一第一可調溫區域(I)在軸向方向上從該反應器底部直到該引導管(7)的一上端形成，一第二可調溫區域(II)在軸向方向上在該引導管(7)的一上端以上形成，並且一第三可調溫區域(III)在該第二區域(II)以上形成並且包括該反應器壁部(2)的一上端(反應器蓋)。 The reactor (1) according to any one of claims 1 to 11, wherein the reactor wall portion (2) is temperature-adjustable, preferably divided into a plurality of arranged in the axial direction. A separately temperature-adjustable region, particularly preferably having three separately temperature-adjustable regions (I, II, III), wherein a first temperature-adjustable region (I) is in the axial direction from the The bottom of the reactor is formed up to an upper end of the guiding tube (7), a second temperature-adjustable region (II) is formed in an axial direction above an upper end of the guiding tube (7), and a third temperature adjustment Zone (III) is formed above this second zone (II) and comprises an upper end (reactor cover) of the reactor wall section (2). 如請求項1~12中任一項所述之反應器(1)，其中，該熱交換器(10)係管式熱交換器並且尤其該熱交換器包括由垂直於軸向方向延伸的蛇管組成的管束，在環境條件及/或工作條件下液態的熱載體流動通過該等蛇管，其中該反應混合物在周圍沖刷該等管或蛇管，或者該熱交換器包括一封閉的管體，該管體具有在軸向方向上延伸的、穿過該管體的管，其中產物通過該等管流動，該等管在該封閉的管體中被在環境條件及/或工作條件下液態的熱載體在周圍沖刷，或者該熱交換器包括在軸向方向上延伸的管或蛇管，在環境條件及/或工作條件下液態的熱載體通過該等管或蛇管流動，其中該反應混合物在周圍沖刷該等管或蛇管。 The reactor (1) according to any one of claims 1 to 12, wherein the heat exchanger (10) is a tubular heat exchanger and in particular the heat exchanger comprises a coil extending perpendicular to the axial direction a bundle of tubes through which liquid heat carriers flow under ambient conditions and/or operating conditions, wherein the reaction mixture flushes the tubes or coils around, or the heat exchanger includes a closed tube, the tube The body has a tube extending through the tubular body extending in the axial direction, wherein the product flows through the tubes, the tubes being liquid in the closed tube body under ambient conditions and/or operating conditions Flushing around, or the heat exchanger includes a tube or coil extending in an axial direction through which liquid heat carriers flow under ambient conditions and/or operating conditions, wherein the reaction mixture is flushed around the tube Wait for a tube or a coil. 一種用於丙交酯聚合的方法，尤其使用如請求項1~13中任一項所述之反應器(1)，其中藉由調節所使用的丙交酯的轉化率，尤其藉由調節該反應混合物的反應溫度，將該反應混合物的黏度設定並保持恆定在1至100Pa．s、較佳的是5至50Pa．s。 A process for the polymerization of lactide, in particular using the reactor (1) according to any one of claims 1 to 13, wherein the conversion of the lactide used is adjusted, in particular by adjusting The reaction temperature of the reaction mixture, the viscosity of the reaction mixture is set and kept constant at 1 to 100 Pa. s, preferably 5 to 50 Pa. s. 如請求項14所述之方法，其中，分別彼此獨立地或彼此組合地a)將該反應混合物的溫度設定在120與200℃之間、較佳的是在130與170℃之間，b)該反應混合物中的催化劑濃度可以設定在5與100ppm之間、較佳的是在15與60ppm之間，其中該催化劑較佳的是選自由錫、鋅、鈦和鋯的有機化合物所組成的群組，c)在該反應混合物中的引發劑濃度設定在0與30mmol/kg之間，其中該 引發劑較佳的是選自由一價、二價、三價和更高價的醇所組成的群組，及/或d)該抑制劑選自由羧酸，較佳的是乳酸，特別較佳的是具有80至100%濃度的含水乳酸所組成的群組，並且在該反應混合物中的抑制劑濃度被設定為，使得在聚合時出現的反應混合物具有在5與15mmol/kg之間、較佳的是5與10mmol/kg之間的羧基濃度。 The method of claim 14, wherein the temperature of the reaction mixture is set to be between 120 and 200 ° C, preferably between 130 and 170 ° C, b) independently or in combination with each other, b) The concentration of the catalyst in the reaction mixture may be set between 5 and 100 ppm, preferably between 15 and 60 ppm, wherein the catalyst is preferably selected from the group consisting of organic compounds of tin, zinc, titanium and zirconium. Group, c) the initiator concentration in the reaction mixture is set between 0 and 30 mmol/kg, wherein Preferably, the initiator is selected from the group consisting of monovalent, divalent, trivalent and higher valent alcohols, and/or d) the inhibitor is selected from the group consisting of carboxylic acids, preferably lactic acid, particularly preferably Is a group consisting of aqueous lactic acid having a concentration of 80 to 100%, and the concentration of the inhibitor in the reaction mixture is set such that the reaction mixture occurring at the time of polymerization has between 5 and 15 mmol/kg, preferably The concentration of carboxyl groups between 5 and 10 mmol/kg. 如請求項14或請求項15所述之方法，其中，該反應混合物的溫度藉由所送入的丙交酯的量及/或溫度及/或借助於該熱交換器(10)及/或藉由送入該熱交換器(10)的熱載體的量及/或溫度來調節。 The method of claim 14 or claim 15, wherein the temperature of the reaction mixture is by the amount and/or temperature of the lactide fed and/or by means of the heat exchanger (10) and/or It is adjusted by the amount and/or temperature of the heat carrier fed to the heat exchanger (10). 如請求項14~16中任一項所述的裝置，其中，借助於在該引導管中的該至少一個攪拌元件(5)建立至少100mbar的動態壓力。 The device according to any one of claims 14 to 16, wherein a dynamic pressure of at least 100 mbar is established by means of the at least one agitating element (5) in the guiding tube. 如請求項14~17中任一項所述的裝置，其中，該熱交換器(10)及/或該引導管(7)完全被該反應混合物遮蓋。 The device of any of claims 14-17, wherein the heat exchanger (10) and/or the guide tube (7) are completely covered by the reaction mixture. 如請求項14~18中任一項所述的裝置，其中，該反應器最高在對應於該反應器(1)的額定容量的10%至100%、較佳的是15至100%、特別較佳的是20至100%的容量下能夠運行或被運行。 The apparatus of any one of claims 14 to 18, wherein the reactor is at most 10% to 100%, preferably 15 to 100%, particularly corresponding to the rated capacity of the reactor (1), It is preferred to be able to operate or be operated at a capacity of 20 to 100%.