1. Introduction
In addition to the three-screw extruder with a twin-screw extruder of plastic and strong, mixed well and have better self-cleaning properties, etc., with the twin-screw, screw rotating every week would add to the mix of materials Lian, and cut the number of kneading, mixing equipment, and scattered mixed melting capacity, in particular, and therefore more conducive to the multi-phase system of MODIFIED blend of materials and extrusion in a row. Three screw extruder screw in the barrel of a word arranged in order, V word order and the order of the three regular triangle. Screw the engagement area increased RCC shear size doubled. Screw in the operation may constitute a highly efficient extrusion material, broken, kneading, rolling and stretching role. It is this highly efficient smelting pinch, so that the three screw without a single screw or twin-screw or the large-diameter aspect ratio can be obtained with the large-diameter aspect ratio or single-, twin-screw extruder The same aircraft the same quality of the output of production performance. Thus the three-screw extruder with a mixture of high-performance characteristics is with the compact structure and a good economy. Three-screw extruder as another dark horse in the field, in the polymer blend modified, high-brightness coating and the production of 21 new convenience food in area such as temporary emerge [1].

2. Research and Development for polymer dynamic three-screw extruder
2.1 Limitations of parallel twin-screw extruder
In parallel with the twin-screw extruders in the single-screw extruder developed on the basis, with mixing, reaction, the second feed, off volatile compounds, such as the advantages of continuity of production, but it inevitably Processing and assembly require high quality products out of difficulties, such as defects. In order to fundamentally solve these problems, can make use of dynamic polymer extrusion technology [2], vibration force field will be the introduction of all-polymer extrusion process equipment in the structure of the Association for the use of axial vibration to strengthen mixed response, exhaust the new structure. At present, the success of the development of the polymer dynamic three-screw extruder, with a high-yield, small noise, heat shortening the course to reduce the number of processing materials arising as a result of the decline in performance, lower power consumption and improve product quality.

2.2 Principle structure of polymer dynamic three-screw extruder

Figure 2.1 for the current series has become the polymer dynamic three-screw extruder structure diagram. Map can be seen from the three screw was arranged in the word, the same size in the middle of the screw shaft power transfer through the distributor and vice power screw me slow down the output shaft and hollow with me slow down the output shaft hollow back-end Linked to the rotation spline rolling in a straight line to make its rotation axis at the same time can be used for pulse. Specially designed vibration of the central main driving force for the screw shaft for excitation transfer, can achieve the vibration frequency and amplitude as two independent parameters were adjusted and control. Gearbox output hollow shaft-driven front-end power distributor. Power distributor and then drive the other two vice-screw [3].

Cyclical vibration of the polymer chain and can produce periodic segment, the direction of more than transient impulse and the proliferation of negative pressure so that the melt viscosity and reduce flexibility, delivery time a corresponding reduction in melt flow resistance, the pressure to reduce crowding, crowded A significant reduction in inflation. Also due to the materials in the state of vibration Phase interface to update a significant increase in frequency, phase and mass transfer and heat transfer greatly enhanced, so that mixing plastics extrusion process to reduce the energy required in the machine to stay within the time and therefore out of To lower the temperature. In addition, the role of the vibration force field, three of the screw mesh material so that the state of residence time distribution, a high degree of orientation were to reach since increased, and therefore significantly improve the quality of the products out of [4].

3. polymer dynamic three-screw extruder applications
Polymer dynamic three-screw extruder has been successfully used in the production of modified plastics, such as PA6 toughened PP, modified calcium carbonate-filled PP, as well as processing for EPDM / PP thermoplastic elastomer-wide dynamic vulcanizate. Below are polymer dynamic three-screw extruder processing PA6 toughened PP, EPDM / PP thermoplastic elastomer-wide dynamic vulcanizate results, with the aim of these products (PP/PA6 modified plastics, EPDM / PP dynamic vulcanizate ) To reflect the performance characteristics of the new processing equipment.

Comparing the performance of the products 3.1
PP/PA6 to target modified plastics, polymers on the dynamic three-screw extruder with the traditional twin-screw extruder to carry out a comparative analysis of the products.

From Table 1, compared with B, physics mechanical properties of large elongation at break, bending modulus and high heat distortion temperature, indicating that the polymer dynamic three-screw extruder Out of the mechanical properties of the blend better. Melt index testing results show that dynamic PP/PA6 out of the product has good post-processing performance.

3.2 vibration force field performance of products

Dynamic three-to screws Polymer Processing EPDM / PP vulcanizate targeted research products on the vibration force field performance of the law.

3.2.1 Frequency of EPDM / PP vulcanizate mechanical properties

(Strength and elongation at break).

Figure 3.2, with the increase in the frequency of vibration, the blend of Shore-A hardness, tear strength values have also increased.

Figure 3.5, we can see that with the increase in the amplitude, tensile strength, elongation at break, tear strength and Shore A hardness, and so on-has been increasing.

As can be seen from Figure 3.6, will be 100% stretch stress changes with the expected trend, with the amplitude is not increased, but decreased first and then increased when the amplitude in the vicinity of 75μm, 100% will be stretched to minimize stress Value.

As a result, polymer dynamic three-screw extruder through the strict control of vibration parameters, so that the vibration frequency and amplitude to achieve a reasonable match, will enable the EPDM / PP dynamic vulcanizate with better performance.

4. Conclusion
Polymer dynamic three-screw extruder to avoid the traditional twin-screw extrusion equipment in many of the shortcomings, is a manufacturer easy to control the quality of products forming a new type of plastic forming equipment. It appears to expand the types of plastics processing equipment, plastics processing equipment to raise the level of play an important role.