阅读说明：本技术 低熔融黏度聚乙醇酸的制备方法 (Preparation method of polyglycolic acid with low melt viscosity ) 是由 崔建中 于 2020-06-04 设计创作，主要内容包括：本发明公开了低熔融黏度聚乙醇酸的制备方法,按照以下步骤操作：将聚乙醇酸颗粒加热至熔融状态,然后通过保温管道输送至螺旋挤出机的进料口；步骤二：螺旋挤出机在加热情况下将混合料挤出至反应箱,所述反应箱的预设温度比螺旋挤出机的加热温度高出5-20摄氏度；待混合料挤出完成之后,将反应箱内的相对湿度调整至70%-85%并搅拌；停止反应箱的加热及加湿,通过向反应箱内注入氮气的方式排出气体；将混合料经过双螺旋挤出机挤出并自然冷却。本发明依次通过单螺旋挤出机的搅拌输送,然后经过升温、加湿、氮气渗入及双螺旋挤出机的梯度降温方式挤出,能够对聚乙醇酸进行一定的处理,降低物料的聚乙醇酸的熔融黏度,提升物料的生物相容性。(The invention discloses a preparation method of polyglycolic acid with low melt viscosity, which is operated according to the following steps: heating polyglycolic acid particles to a molten state, and conveying the polyglycolic acid particles to a feed port of a screw extruder through a heat-insulating pipeline; step two: extruding the mixture to a reaction box by a screw extruder under the heating condition, wherein the preset temperature of the reaction box is 5-20 ℃ higher than the heating temperature of the screw extruder; after the mixture is extruded, adjusting the relative humidity in the reaction box to 70-85% and stirring; stopping heating and humidifying the reaction box, and discharging gas in a mode of injecting nitrogen into the reaction box; extruding the mixture by a double-screw extruder and naturally cooling. The polyglycolic acid is conveyed by stirring of the single-screw extruder in sequence, and then is extruded in a gradient cooling mode of heating, humidifying, nitrogen permeating and double-screw extruder, so that polyglycolic acid can be treated to a certain extent, the melt viscosity of polyglycolic acid of the material is reduced, and the biocompatibility of the material is improved.)

1. The preparation method of the polyglycolic acid with low melt viscosity is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: heating polyglycolic acid particles to a molten state, and conveying the polyglycolic acid particles to a feed port of a screw extruder through a heat-insulating pipeline;

step two: extruding the mixture to a reaction box by a screw extruder under the heating condition, wherein the preset temperature of the reaction box is 5-20 ℃ higher than the heating temperature of the screw extruder;

step three: after the mixture is extruded, adjusting the relative humidity in the reaction box to 70-85% and stirring;

step four: stopping heating and humidifying the reaction box, and discharging gas in a mode of injecting nitrogen into the reaction box;

step five: extruding the mixture by a double-screw extruder and naturally cooling.

2. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: the screw extruder in the first step is a single screw extruder.

3. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: in the first step, the heating temperature is 5-20 ℃ higher than the melting point temperature of the polyglycolic acid particles.

4. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: and in the second step, the preset temperature of the reaction box is 13 ℃ higher than the heating temperature of the screw extruder.

5. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: the relative humidity in the reaction chamber in step three was 88%.

6. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: in step four, nitrogen was added through the bottom of the reaction chamber.

7. The method for producing polyglycolic acid with low melt viscosity according to claim 1, which comprises: the double-screw extruder in the step five comprises four heating areas, and the temperatures of the four heating areas are respectively set as follows during extrusion operation: 290-305 deg.c, 265-275 deg.c, 250-260 deg.c and 230-220 deg.c.

8. The method for producing polyglycolic acid with low melt viscosity according to claim 7, which comprises: the temperatures of the four heating zones were set to: 300 deg.C, 270 deg.C, 255 deg.C, 225 deg.C.

Technical Field

The invention relates to the technical field of manufacturing of polyethanol, in particular to a preparation method of polyglycolic acid with low melt viscosity.

Background

High molecular materials are increasingly widely applied to the medical field, and in the research and development of medical high molecular materials, degradable high molecular materials are applied to many fields such as operation sutures, artificial skin, artificial blood vessels, bone fixation and repair, drug controlled release, erythrocyte carriers and the like. Many developed countries begin to research from the sixties of the twentieth century, and the initial degradable materials are only applied to drug slow release, suture lines and the like, and the development of polymer polymerization technology and plastic processing technology, especially the development of composite film reinforcement technology, in the eighties of the twentieth century, the degradable bone materials have a greater incidence rate of bone defects caused by trauma and the like in clinic, which is known through extensive research and research at home and abroad.

The existing method always adopts metal materials such as stainless steel and the like as the internal fixing material for bone repair, but has obvious defects: firstly, the stimulation of physiological stress of the section can be reduced due to the firmness of the metal material, and the function of replacing the stress shielding protection is formed, so that the osteoporosis is formed; secondly, because the metal material can not be biodegraded, the bone needs to be taken out after healing, the pain of the patient is increased; thirdly, metal anchoring materials can cause some complications. For the above reasons, it is desired to find a material which can meet the requirements of bone repair fixation and can be biodegraded in vivo to replace widely used stainless steel materials as bone repair internal fixation materials, so polyglycolic acid (PGA) becomes the first choice material, and as a medical material, polyglycolic acid has good biocompatibility as the first condition, and studies show that the good or bad of biocompatibility is related to the melt viscosity of polyglycolic acid, and the lower the melt viscosity indicates that the biocompatibility is better.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides a preparation method of polyglycolic acid with low melt viscosity.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the preparation method of the polyglycolic acid with low melt viscosity comprises the following steps: the method comprises the following steps:

the method comprises the following steps: heating polyglycolic acid particles to a molten state, and conveying the polyglycolic acid particles to a feed port of a screw extruder through a heat-insulating pipeline;

step two: extruding the mixture to a reaction box by a screw extruder under the heating condition, wherein the preset temperature of the reaction box is 5-20 ℃ higher than the heating temperature of the screw extruder;

step three: after the mixture is extruded, adjusting the relative humidity in the reaction box to 70-85% and stirring;

step four: stopping heating and humidifying the reaction box, and discharging gas in a mode of injecting nitrogen into the reaction box;

step five: extruding the mixture by a double-screw extruder and naturally cooling.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: the screw extruder in the first step is a single screw extruder.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: in the first step, the heating temperature is 5-20 ℃ higher than the melting point temperature of the polyglycolic acid particles.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: and in the second step, the preset temperature of the reaction box is 13 ℃ higher than the heating temperature of the screw extruder.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: the relative humidity in the reaction chamber in step three was 88%.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: in step four, nitrogen was added through the bottom of the reaction chamber.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: the double-screw extruder in the step five comprises four heating areas, and the temperatures of the four heating areas are respectively set as follows during extrusion operation: 290-305 deg.c, 265-275 deg.c, 250-260 deg.c and 230-220 deg.c.

In a preferred embodiment of the present invention, the method for producing polyglycolic acid having a low melt viscosity comprises: the temperatures of the four heating zones were set to: 300 deg.C, 270 deg.C, 255 deg.C, 225 deg.C.

The invention achieves the following beneficial effects: compared with the prior art, the polyglycolic acid processing method has the advantages that the polyglycolic acid is conveyed by stirring of the single-screw extruder in sequence, and then is extruded in a gradient cooling mode of a double-screw extruder through heating, humidifying and nitrogen permeating, so that a certain amount of polyglycolic acid can be processed, the melt viscosity of polyglycolic acid of materials is reduced, and the biocompatibility of the materials is improved.

Detailed Description

The invention is further described below. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

This example discloses a method for preparing polyglycolic acid with low melt viscosity, which comprises the following steps:

the method comprises the following steps: the polyglycolic acid particles are heated to a molten state, preferably at a temperature 5 to 20 ℃ higher than the melting point temperature of the polyglycolic acid particles. Then conveyed to a feed inlet of a screw extruder through a heat-insulating pipeline. In the single screw extruder, friction dragging is adopted in the solid conveying section, viscosity dragging is adopted in the melt conveying section, and the flow velocity distribution is uniform, so that the material mixing is facilitated.

Step two: the screw extruder extrudes the mixture to a reaction box under the heating condition, the preset temperature of the reaction box is 5-20 ℃ higher than the heating temperature of the screw extruder, and the optimal higher temperature is 13 ℃.

Step three: after the mixture is extruded, adjusting the relative humidity in the reaction box to 70-85% and stirring; the optimum relative humidity in the chamber should be 88%.

Step four: stopping heating and humidifying the reaction box, and discharging gas in a mode of injecting nitrogen into the reaction box; in the process of adding nitrogen, the nitrogen is preferably added into the reaction box through the gas adding hole at the bottom of the reaction box, so that the internal gas can be discharged conveniently, and the waste of nitrogen is avoided.

Step five: extruding the mixture by a double-screw extruder and naturally cooling. The twin-screw extruder is selected in the step because the complex flow spectrum of the materials of the twin-screw extruder shows the advantages that a single-screw extruder cannot compare favorably on a macroscopic scale, and the advantages comprise sufficient mixing, good heat transfer, large melting capacity 1653, strong exhaust capacity, good material temperature control and the like.

The twin screw extruder of the present embodiment includes four heating zones, and the temperatures of the four heating zones are set to: 290-305 deg.c, 265-275 deg.c, 250-260 deg.c and 230-220 deg.c. Thus, gradient cooling can be carried out in the process of extruding the material, and the temperatures of the four heating areas are preferably set as follows: 300 deg.C, 270 deg.C, 255 deg.C, 225 deg.C.

Compared with the prior art, the embodiment sequentially carries through the stirring of the single-screw extruder, and then extrudes in a gradient cooling mode of heating, humidifying, nitrogen permeating and the double-screw extruder, so that polyglycolic acid can be treated to a certain extent, the melt viscosity of polyglycolic acid of materials is reduced, and the biocompatibility of the materials is improved.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.