CN209335866U - A kind of underwater cutpellet die head for processing polylactic acid - Google Patents

Abstract

An underwater pelletizing die for processing polylactic acid, comprising a die body composed of an inner core and an outer core connected to each other, the periphery of the die body is fixed with an outer edge of the die for connecting with an external barrel, The inside of the inner mold core and the outer mold core are respectively provided with a first channel and a second channel, the first channel and the second channel communicate with each other, and the outer surfaces of the ends of the inner mold core and the outer mold core respectively form a material inlet and a material outlet. There is a rotating shaft in the center of the outer surface of the end of the outer mold core, and the cutter is rotatably fixed on the rotating shaft through the rotating arm to cut the polylactic acid material output from the discharge hole into regular-shaped particles. The utility model uses a plurality of ring-shaped feeding ports arranged in the inner mold core to make the pressure of the melt in the material cylinder uniform when extruded to the die through the rotation of the screw, which solves the problem of uneven pressure and The problem of accumulated material can be improved, and the surface finish and performance of the product can be improved.

Description

An underwater pelletizing die for processing polylactic acid

technical field

The utility model relates to an underwater pelletizing die head for processing polylactic acid, which belongs to the technical field of polymer material processing and manufacturing.

Background technique

Polylactic acid (PLA) is a linear aliphatic polyester. It is a non-toxic, non-irritating and fully biodegradable plastic with the most market potential. The role of PLA and its products in microorganisms Under the environment, it can be 100% degraded into carbon dioxide and water, which is unmatched by other plastics, so it is favored by European and American countries. This new biodegradable material has outstanding advantages in terms of mechanical properties and biodegradable properties.

At present, countries all over the world are calling for environmental protection, and global crude oil resources continue to be tight, causing the price of petroleum-based plastic raw materials to soar, making the development and utilization of polylactic acid a hot topic for developed countries. Now most of the production of PLA resin is in the United States and China. China, while the development of China's PLA resin and its finished products is still in its infancy, and many domestic manufacturers are planning to invest in, develop and research the production process and equipment of PLA resin and finished products.

The interior of the connection between the traditional die-sticking die and the barrel is conical, and there is a large gap inside the barrel, which is easy to form accumulation during processing. Due to the good temperature resistance of conventional plastics, it will not It will cause a big problem to the performance of the material itself, but because polylactic acid is a heat-sensitive material, it is more sensitive to temperature, moisture, etc., and the traditional underwater circular cutting die has accumulated material on the die, so PLA is easy to be thermally degraded after long-term processing, and Black spots are caused by carbon deposits after shutdown, which affects product quality.

Utility model content

The technical problem to be solved by the utility model is to provide an underwater pelletizing die head for processing polylactic acid in view of the deficiencies in the prior art. Through a plurality of annular feeding ports arranged in the inner mold core, the melt in the barrel The pressure is uniform when the screw is rotated and extruded to the die, which solves the problems of uneven pressure and material accumulation in the process of traditional die processing, and improves the surface finish and performance of the product.

The technical problem to be solved by the utility model is achieved through the following technical solutions:

An underwater pelletizing die head for processing polylactic acid, comprising a die head body composed of an inner mold core and an outer mold core connected to each other, the outer periphery of the die head body is fixed with an outer die head for connecting with an external barrel. Along the inside of the inner mold core and the outer mold core, there are respectively a first channel and a second channel, and the first channel and the second channel communicate with each other, respectively outside the ends of the inner mold core and the outer mold core. The surface forms an annular feed inlet and a discharge hole, and the center of the outer surface of the end of the outer mold core is provided with a rotating shaft. The cutter is rotatably fixed on the rotating shaft through a rotating arm, and the poly The lactic acid material is cut into regular shaped particles.

Specifically, in order to maintain stable feed pressure, uniform discharge, and consistent particle size, the first channel includes an annular channel arranged axially along the inner mold core, the number of which is multiple layers, and the annular channel is in the The outer end of the mold core forms the annular feed opening; the number of the first channels is two layers.

Further, the second channel is a through hole; the number of discharge holes formed by the through hole on the outer surface of the end of the outer mold core is multiple, centered on the rotating shaft, outside the outer mold core A plurality of concentric circles are formed at the end, and the setting position of each concentric circle corresponds to the first channel.

In addition, a transition part is provided between the inner mold core and the outer mold core, and an opening is provided on the transition part, and the positions of the openings are respectively connected with the first channel and the first channel arranged on both sides thereof. corresponding to the second channel.

The inner mold core includes two parts, a truncated cone and a cylinder, which are integrally arranged.

Furthermore, the cutter is a sheet-like structure, the middle part of which is fixed on the rotating arm, and an angle α is formed between the installation plane of the cutter and the plane where the discharge hole is located, and the cutter One side edge of the knife is close to the plane where the discharge hole is located.

In order to effectively cut the material into particles, the range of the included angle α is: 0°<α<5°.

In order to improve work efficiency and maintain structural balance and stability, the number of cutters is two.

To sum up, the utility model provides an underwater pelletizing die for processing polylactic acid, through a plurality of annular feed ports set in the inner core, the melt is extruded to the die in the barrel through the rotation of the screw The pressure is uniform during processing, which solves the problems of uneven pressure and material accumulation in the process of traditional die head processing, and improves the surface finish and performance of the product.

The technical solutions of the present utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the appended drawings in the following description The drawings show some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creative work.

Fig. 1 is the axial sectional schematic view of the utility model;

Fig. 2 is a schematic diagram of the A-A sectional structure of Fig. 1;

Fig. 3 is a schematic diagram of the structure of the end face of the die with the cutter installed.

Detailed ways

In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model.

Fig. 1 is a schematic diagram of an axial section of the utility model; Fig. 2 is a schematic diagram of the A-A section structure of Fig. 1; Fig. 3 is a schematic diagram of the end face structure of a die head equipped with a cutter. As shown in Fig. 1 and in conjunction with Fig. 2 and Fig. 3, the utility model provides an underwater pelletizing die for processing polylactic acid, which includes a die body composed of an inner core 100 and an outer core 200 connected to each other. In the embodiment shown in FIG. 1 , the inner mold core 100 includes two parts, a truncated cone and a cylinder, and the outer mold core 200 is a cylinder. The periphery of the die body is fixed with a die outer edge 300 for connecting with the outer barrel 700 . Wherein, the inner mold core 100 and the outer mold core 200 are connected through tapping, and the outer mold core 200 is connected with the outer edge 300 of the die head through bolts. During operation, when the inner mold core 100 is connected with the outer barrel 700, in order to prevent material leakage, the two must be tightly sealed.

The inner mold core 100 and the outer mold core 200 are provided with a first channel 101 and a second channel 201 respectively, and the first channel 101 and the second channel 201 communicate with each other, and the two can be directly communicated as required, It can also be indirectly connected. The first channel 101 and the second channel 201 respectively form an annular feed inlet 110 and a discharge hole 210 on the outer surface of the end of the inner mold core 100 and the outer mold core 200, and the outer surface of the end of the outer mold core 200 A rotating shaft 400 is arranged in the center, and a cutter 500 is rotatably fixed on the rotating shaft 400 through a rotating arm 600 to cut the polylactic acid material output from the discharge hole 210 into regular-shaped particles.

As shown in Figure 2, in order to maintain a stable feed pressure, uniform discharge, and consistent particle size, the first channel 101 provided on the inner core 100 is annular. Specifically, the first channel 101 includes along the The annular passage arranged axially in the inner mold core 100 has multiple layers. In the embodiment shown in FIG. 2, the first passage 101 is provided with two layers. Adjust the number of layers of the ring channel according to the demand of production. An annular channel forms the annular feed opening 110 at the outer end of the inner core 100 . The melt enters the die head body from the barrel 700, reducing sudden pressure changes in the process of changing from a cylindrical shape to a ring shape, and greatly improving the uniformity of the output.

As shown in FIG. 1 , further, the second channel 201 is a through hole penetrating the outer mold core 200 , and the number of discharge holes 210 formed by the through hole on the outer surface of the end of the outer mold core 200 is multiple. As shown in FIG. 3 , with the rotating shaft 400 as the center, a plurality of concentric circles are formed on the outer end of the outer mold core 200, and the setting position of each concentric circle corresponds to the first channel 101, so that Ensure that the material enters the die head from the inner mold core 100 and can be smoothly output from the discharge hole 210 of the outer mold core 200 . In order to ensure uniform discharge, the distance between two adjacent discharge holes 210 on the concentric circles is equal to each other. Therefore, from the overall perspective of the ring-shaped area where the discharge holes formed by multiple concentric circles are concentrated, The discharge holes 210 are evenly distributed. In this way, during the cutting process, under the premise that the amount of material is sufficient, the materials output from each discharge hole 210 will not interfere with each other, and the cut particles are of equal size. The above structure enables the melt to be resisted in the die body after high-pressure extrusion from the barrel, but it will not cause different pressures at various parts during the extrusion process, thereby ensuring uniform discharge and consistent particle size.

As shown in Figure 1, in order to facilitate the connection, a transition part 120 is provided between the inner mold core 100 and the outer mold core 200, and an opening 121 is provided on the transition part 120. In order to facilitate the circulation of materials, the The positions of the holes 121 are respectively corresponding to the first channel 101 and the second channel 201 disposed on both sides thereof.

It should be noted that the positions and sizes of the first channel 101, the opening 121 and the second channel 201 in FIG. , not to the size ratio shown in the illustration.

In addition, as shown in Figure 1, in order to ensure a constant temperature working environment, the die head body is wrapped with a heating sheet 800, and the heating sheet 800 is wrapped in the die head body formed by connecting the inner mold core 100 and the outer mold core 200 in sequence. The material in the first channel 101 and the second channel 201 is heated through the inner mold core 100 and the outer mold core 200 to ensure that it is in a flowing state. In order to monitor and adjust the pressure and temperature in time to ensure the best working conditions, the bottom of the die body is provided with installation holes for installing the pressure sensor 910 and the temperature sensor 920 respectively. Since the pressure sensor 910 and the temperature sensor 920 are existing technologies, those skilled in the art can select them according to the actual working environment and installation location, and their structures and working principles will not be repeated here.

As shown in FIG. 3 , a rotating shaft 400 is provided in the middle of the outer end face of the outer mold core 200 , one end of the rotating arm 600 is fixed on the rotating shaft 400 , and the other end is fixed in the middle of the cutter 500 . The cutting knife 500 has a sheet structure, and fixing the middle part on the rotating arm 600 can make the cutting knife 500 receive more uniform force when the rotating arm 600 rotates with the rotating shaft 400 . In order to cut the material conveniently, an angle α is formed between the plane of the cutter 500 and the plane where the discharge hole 210 is located, and one side edge of the cutter 500 is close to the plane where the discharge hole 210 is located. In order to effectively cut the material into particles, the range of the included angle is: 0°<α<5°. In addition, in order to improve work efficiency and maintain structural balance and stability, the number of cutters 500 is two. Of course, one or more can also be selected as required.

As shown in Figures 1 to 3, the working process of the present utility model is as follows:

Connect the inner mold core 100 of the die body with the external barrel 700, and the material enters the inner mold core 100 from the outer barrel 700 along the first channel 101 in sequence. At this time, since the first channel 101 adopts a multi-layer annular Structural channels, the melt enters the die body from the barrel 700, reducing sudden pressure changes in the process of changing from a cylindrical shape to a ring shape, and greatly improving the uniformity of the output. Subsequently, the melt passes through the opening 121 on the transition part 120 from the first passage 101 successively, flows through the second passage 201 in the outer mold core 200, and finally discharges from the annular area on the outer end surface of the outer mold core 200. Hole 210 output. At the same time, the rotating arm 600 rotates under the action of the rotating shaft 400 to drive the cutter 500 to cut the material output from the discharge hole 210 in a direction forming a fixed angle with the plane where the discharge hole 210 is located. By controlling the pressure, temperature, material discharge speed and the rotation speed of the rotating shaft, the cut particles are guaranteed to be uniform and complete.

The granulation die head provided by the utility model is mainly used for the processing of polymer materials. After the material is melted, the material extruded by pressure is cut into granules through the rotation of the cutting knife on the outermost side of the die head body. Since the inner mold core, outer mold core and the outer edge of the die head are curved cone, curved truncated cone and cylinder respectively, there is no accumulation of residual material during the process of material transmission and cutting. The pressure is stable and even.

The above descriptions are only examples of the present utility model, and are not intended to limit the present utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included in the scope of claims of the present utility model.

To sum up, the utility model provides an underwater pelletizing die for processing polylactic acid, through a plurality of annular feed ports set in the inner core, the melt is extruded to the die in the barrel through the rotation of the screw The pressure is uniform during processing, which solves the problems of uneven pressure and material accumulation in the process of traditional die head processing, and improves the surface finish and performance of the product.

Claims (9)

1. a kind of underwater cutpellet die head for processing polylactic acid, including the inner mould core and the die head sheet that constitutes of outer core rod by being connected with each other Body, the periphery of the die head ontology are installed with the die head outer for being connected with external barrel, which is characterized in that the inner mould core With first passage and second channel are offered inside outer core rod respectively, the first passage and second channel communicate with each other, respectively Annular feed inlet and discharge hole, the end outer surface of the outer core rod are formed in the end outer surface of the inner mould core and outer core rod Center is equipped with shaft, and cutter is fixed in the shaft by the way that pivoted arm is rotatable.

2. the underwater cutpellet die head of processing polylactic acid as described in claim 1, which is characterized in that the first passage includes edge The circular passage that the inner mould core is axially arranged, setting quantity are multilayer, outboard end shape of the circular passage in the inner mould core At the annular feed inlet.

3. the underwater cutpellet die head of processing polylactic acid as claimed in claim 2, which is characterized in that the setting of the first passage Quantity is two layers.

4. the underwater cutpellet die head of processing polylactic acid as claimed in claim 2, which is characterized in that the second channel is logical Hole；

The through-hole outer core rod end outer surface formed discharge hole quantity be it is multiple, centered on the shaft, The outboard end of the outer core rod forms multiple concentric circles, and the setting position of each concentric circles is corresponding with the first passage.

5. the underwater cutpellet die head of processing polylactic acid as claimed in claim 4, which is characterized in that the inner mould core and outer core rod Between be equipped with transition part, the transition part be equipped with aperture, the setting position of the aperture respectively with its two sides is set The first passage and second channel are corresponding.

6. the underwater cutpellet die head of processing polylactic acid as described in claim 1, which is characterized in that the inner mould core includes one Two parts of the frustum of a cone and cylindrical body of setting.

7. the underwater cutpellet die head of processing polylactic acid as described in claim 1, which is characterized in that the cutter is sheet knot Structure, middle part are fixed on the pivoted arm, are in an angle between plane where the setting plane of the cutter and the discharge hole α, and plane where the one side edge of the cutter close to the discharge hole.

8. the underwater cutpellet die head of processing polylactic acid as claimed in claim 7, which is characterized in that the range of the angle α are as follows: 0 ° of 5 ° of < α <.

9. the underwater cutpellet die head of processing polylactic acid as claimed in claim 7, which is characterized in that the setting quantity of the cutter It is two.