阅读说明：本技术 聚丙烯中空树脂粒子及其挤出机构与空心发泡聚丙烯珠粒 (Polypropylene hollow resin particle, extrusion mechanism thereof and hollow foamed polypropylene bead ) 是由 唐涛 邢海平 邱健 姜治伟 于 2019-10-24 设计创作，主要内容包括：本发明涉及一种聚丙烯中空树脂粒子及其挤出机构与空心发泡聚丙烯珠粒,属于挤出机构技术领域。本发明的挤出机构,包括同轴设置的螺钉头、螺钉杆、分流锥和导流柱；螺钉头上设有多个贯穿螺钉头上下表面的出料孔,且多个出料孔在螺钉头的上表面的圆心的连线能够形成内角均≥90°的多边形；螺钉杆为中空杆,顶端固定在螺钉头的下表面上,内腔与出料孔连通,外壁上设有外螺纹；分流锥和导流柱分别为倒圆锥形和正圆锥形,分别固定在螺钉头的下表面和上表面上。该挤出机构既能保证挤出料从出料孔出料的均匀性,又能方便的调整挤出胀大比,还能防止各出料孔发生内粘连,堵塞中孔,挤出的树脂粒子能够避免发泡后由于填充不足产生的缺陷。(The invention relates to a polypropylene hollow resin particle, an extrusion mechanism thereof and a hollow foaming polypropylene bead, belonging to the technical field of extrusion mechanisms. The extrusion mechanism comprises a screw head, a screw rod, a shunting cone and a guide column which are coaxially arranged; the screw head is provided with a plurality of discharge holes penetrating through the upper surface and the lower surface of the screw head, and the connecting lines of the plurality of discharge holes at the circle center of the upper surface of the screw head can form polygons with inner angles of more than or equal to 90 degrees; the screw rod is a hollow rod, the top end of the screw rod is fixed on the lower surface of the screw head, the inner cavity of the screw rod is communicated with the discharge hole, and the outer wall of the screw rod is provided with external threads; the shunting cone and the diversion column are respectively in an inverted cone shape and a right cone shape and are respectively fixed on the lower surface and the upper surface of the screw head. This extrusion mechanism can guarantee to extrude the material from the homogeneity of discharge opening ejection of compact, and the bloated ratio is extruded in adjustment that again can be convenient, can also prevent that each discharge opening from taking place the internal adhesion, blocks up the mesopore, and the resin particle of extruding can avoid the defect because the not enough production of packing after the foaming.)

1. The polypropylene hollow resin particle extrusion mechanism is characterized by comprising a screw head, a screw rod, a shunting cone and a diversion column which are coaxially arranged;

the cross section of the screw head is in a regular hexagon shape, a plurality of discharge holes with central axes parallel to the central axis of the screw head are arranged on the screw head, the discharge holes penetrate through the upper surface and the lower surface of the screw head, and the connecting lines of the discharge holes at the circle center of the upper surface of the screw head can form a polygon with an inner angle of more than or equal to 90 degrees;

the screw rod is a hollow rod, the top end of the screw rod is fixed on the lower surface of the screw head, the inner cavity of the screw rod is communicated with the discharge hole, and external threads are arranged on the outer wall of the screw rod;

the shunting cone is arranged in an inner cavity of the screw rod, the shunting cone is in an inverted cone shape, the top surface of the shunting cone is fixed on the lower surface of the screw head, the connecting positions of the shunting cone and the screw head are all positioned at the inner side of the discharge hole, and an angle between the shunting cone and the lower surface of the screw head is 5-85 degrees;

the flow guide column is in a right circular cone shape, the bottom surface of the flow guide column is fixed on the upper surface of the screw head, and the connecting parts of the flow guide column and the screw head are located on the inner side of the discharge hole.

2. The polypropylene hollow resin particle extrusion mechanism as claimed in claim 1, wherein the diameter of the discharge hole is 0.2-2.4 mm.

3. The polypropylene hollow resin particle extrusion mechanism according to claim 1, wherein the connecting lines of the plurality of discharge holes at the center of the upper surface of the screw head form a pentagon or a hexagon.

4. The polypropylene hollow resin particle extrusion mechanism as claimed in claim 1, wherein the side length of the regular hexagon of the cross section of the screw head is 5mm, the thickness of the screw head is 2.0-5.0mm, the length of the screw rod is 12-20mm, and the diameter of the inner cavity of the screw rod is 2.8-6 mm.

5. The polypropylene hollow resin particle extrusion mechanism as claimed in claim 1, wherein the maximum diameter of the diverging cone is 2.8 to 6.0 mm.

6. The polypropylene hollow resin particle extrusion mechanism as claimed in claim 1, wherein the maximum diameter of the guide pillar is 2.8-6.0 mm.

7. The polypropylene hollow resin particle extrusion mechanism of claim 1, further comprising a fixing screw, wherein a groove is formed in the top surface of the tap cone, an internal thread is formed in the groove, the flow guiding column is provided with a first through hole along the central axis of the flow guiding column, a second through hole is formed in the screw head, a screw cap of the fixing screw is clamped at the top end of the first through hole, a screw rod of the fixing screw sequentially penetrates through the first through hole and the second through hole, and an external thread at the bottom of the screw rod of the fixing screw is in threaded fit with an internal thread of the groove of the tap cone.

8. The polypropylene hollow resin particle extrusion mechanism as claimed in claim 1, wherein the angle of the flow guide pillar to the upper surface of the screw head at the connection point is 5 ° to 85 °.

9. The polypropylene hollow resin particle extrusion means as claimed in any one of claims 1 to 8, which extrudes the produced polypropylene hollow resin particle.

10. A hollow expanded polypropylene bead obtained by expanding a polypropylene hollow resin particle produced by the polypropylene hollow resin particle extruding means as recited in any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of extrusion mechanisms, and particularly relates to polypropylene hollow resin particles, an extrusion mechanism thereof and hollow foamed polypropylene beads.

Background

The foamed Polypropylene material (EPP) is a high-crystallinity polymer/gas composite material with excellent performance, and becomes a novel environment-friendly compression-resistant buffering and heat-insulating material which is the fastest growing at present due to unique and superior performance. The polypropylene expanded beads are prepared by using polypropylene as a main raw material and adopting a physical expansion technology, and are mainly used for carrying out mould expansion molding to form various shapes and sizes for different occasions. Compared with common foaming materials such as EPS and EPE, the polypropylene foaming beads and the polypropylene foaming products molded by using the polypropylene foaming bead die have a plurality of excellent performances, so that the application field of EPP is more and more extensive, and the EPP is most prominently embodied in the packaging field and the automobile industry field, such as IT products, electronic communication equipment, liquid crystal displays, plasma color televisions, precise electronic components, precise instruments and meters and the like, and the EPP is used as a packaging material in a large amount; and EPP materials are used in large quantities in automobile bumpers, automobile side shockproof cores, high-grade safety automobile seats, tool boxes, trunk boxes, armrests, base plates, sun shields, instrument panels and the like, and according to statistics, the automobile is made of 100-130kg of plastic materials on average, wherein the EPP plastic is about 4-6 kg.

Disclosure of Invention

The invention provides a polypropylene hollow resin particle, an extrusion mechanism thereof and a hollow foaming polypropylene bead, which are used for solving the technical problems that the existing extrusion mechanism has the defects of non-uniform discharge, incapability of obtaining a mesopore due to wire adhesion, and insufficient filling of a foaming particle in a mould due to the lower filling rate of the existing cylindrical foaming particle.

The technical scheme adopted by the invention for solving the technical problems is as follows.

The invention provides a polypropylene hollow resin particle extrusion mechanism, which comprises a screw head, a screw rod, a shunting cone and a diversion column which are coaxially arranged;

the cross section of the screw head is in a regular hexagon shape, a plurality of discharge holes with central axes parallel to the central axis of the screw head are arranged on the screw head, the discharge holes penetrate through the upper surface and the lower surface of the screw head, and the connecting lines of the discharge holes at the circle center of the upper surface of the screw head can form a polygon with an inner angle of more than or equal to 90 degrees;

the screw rod is a hollow rod, the top end of the screw rod is fixed on the lower surface of the screw head, the inner cavity of the screw rod is communicated with the discharge hole, and external threads are arranged on the outer wall of the screw rod;

the shunting cone is arranged in an inner cavity of the screw rod, the shunting cone is in an inverted cone shape, the top surface of the shunting cone is fixed on the lower surface of the screw head, the connecting positions of the shunting cone and the screw head are all positioned at the inner side of the discharge hole, and an angle between the shunting cone and the lower surface of the screw head is 5-85 degrees;

the flow guide column is in a right circular cone shape, the bottom surface of the flow guide column is fixed on the upper surface of the screw head, and the connecting parts of the flow guide column and the screw head are located on the inner side of the discharge hole.

Furthermore, the diameter of the discharge hole is 0.2-2.4 mm.

Furthermore, the connecting lines of the discharging holes at the circle centers of the upper surfaces of the screw heads form pentagons or hexagons.

Further, the side length of the regular hexagon of the cross section of the screw head is 5mm, and the thickness of the screw head is 2.0-5.0 mm.

Furthermore, the length of the screw rod is 12-20mm, and the diameter of the inner cavity of the screw rod is 2.8-6 mm.

Further, the maximum diameter of the splitter cone is 2.8-6.0 mm.

Furthermore, the maximum diameter of the flow guide column is 2.8-6.0 mm.

Furthermore, the angle between the flow guide column and the upper surface of the screw head at the connecting position is 5-85 degrees.

Further, extruding means still includes the fixed screw, and the top surface of reposition of redundant personnel awl is equipped with the recess, is equipped with the internal thread in the recess, and the water conservancy diversion post is equipped with first through-hole along its self center pin, is equipped with the second through-hole on the screwhead, and the nut card of fixed screw is on the top of first through-hole, and the lead screw of fixed screw passes first through-hole and second through-hole in proper order, the external screw thread of the lead screw bottom of fixed screw and the internal thread screw-thread fit of the recess of reposition of redundant personnel awl.

The invention also provides the polypropylene hollow resin particles extruded by the extruding mechanism for the polypropylene hollow resin particles.

The invention also provides hollow expanded polypropylene beads obtained by foaming the polypropylene hollow resin particles produced by the polypropylene hollow resin particle extrusion mechanism.

Compared with the prior art, the invention has the beneficial effects that:

the extrusion mechanism for the polypropylene hollow resin particles is provided with the shunting cone, the angle arranged at the joint of the shunting cone and the screw head is 5-85 degrees, so that the flow of an extruded material in a screw rod is subjected to shear deformation, and the extrusion swelling is caused by the normal stress in the direction vertical to the shear direction. Patent document 2 can control the extrusion swelling ratio of the corresponding extrusion material by controlling the size of the chamfer angle alpha, if the extrusion swelling ratio is too high, a middle hole may be blocked, if the extrusion swelling ratio is too small, two adjacent threads of eight threads may not be bonded together, and hollow cylindrical threads cannot be formed.

The extruding mechanism for the polypropylene hollow resin particles is provided with the guide column outside the screw head, so that the discharge holes are prevented from being internally adhered to block the middle hole.

According to the extruding mechanism for the polypropylene hollow resin particles, the extruded polypropylene hollow resin particles are cylinders, the hollow rate is high, the cross section is not in a perfect circle shape, the longest radial length of the cross section of the polypropylene hollow resin particle passing through the center is D, the shortest radial length of the cross section of the polypropylene hollow resin particle passing through the center is D, and D/D is more than or equal to 0.2 and less than 1; the hollow expanded polypropylene beads prepared by the common foaming method have small cross section area, are beneficial to filling during molding, and the obtained product has good appearance, thereby avoiding the defect caused by insufficient filling.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic view showing the structure of an extrusion mechanism for hollow polypropylene resin particles according to the present invention;

FIG. 2 is a schematic view (plan view) showing the distribution of a plurality of discharge holes of the extruding means for hollow polypropylene resin particles according to the present invention; the material a is distributed in a regular pentagon shape, the material b is distributed in a regular hexagon shape, the material c is distributed in an irregular pentagon shape, and the material d is distributed in an irregular hexagon shape;

FIG. 3 is a schematic view showing the structure of an extruding mechanism for polypropylene hollow resin particles according to the present invention (including a fixing screw);

in the figure, the screw head 1, the screw head 2, the screw rod 3, the shunt cone 4, the flow guide column 5 and the fixing screw.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1 to 3, the polypropylene hollow resin particle extrusion mechanism of the present invention includes a screw head 1, a screw rod 2, a tap cone 3 and a guide post 4 which are coaxially arranged.

The cross section of the screw head 1 is a regular hexagon, a plurality of discharge holes with central axes parallel to the central axis of the screw head 1 are arranged on the screw head 1, the discharge holes penetrate through the upper surface and the lower surface of the screw head 1, and the connecting lines of the discharge holes at the circle center of the upper surface of the screw head 1 can form polygons with inner angles equal to or larger than 90 degrees, and the polygons can be regular polygons or irregular polygons, such as irregular pentagons or irregular hexagons. The thickness of the screw head 1 and the side length of the cross section are set according to requirements, and the thickness is usually 2.0-2.5mm, and the side length of the cross section is 5 mm. The diameter of the discharge hole is set according to the requirement, and is usually 0.2-2.4 mm; when the connecting line of the discharge hole at the center of the circle of the upper surface of the screw head forms a regular polygon, the diameter of the circumference where the discharge hole is located is 2.8-6.0 mm.

The screw rod 2 is a hollow rod, the length and the inner cavity are set according to requirements, the length is 12-20mm generally, and the diameter of the inner cavity is 2.8-6 mm. The top end of the screw rod 2 is fixed on the lower surface of the screw head 1, and the inner cavity of the fixed screw rod 2 is communicated with the discharge hole. The outer wall of the screw rod 2 is provided with an external thread.

The diffluence cone 3 is arranged in the inner cavity of the screw rod 2, the diffluence cone 3 is in an inverted cone shape, the top surface is fixed on the lower surface of the screw head 1, the diffluence cone 3 does not block the discharge hole, namely, the outer edge of the top surface of the diffluence cone 3 is positioned at the inner side of the discharge hole. The inner diameter of the splitter cone 3 is set as required, and the maximum diameter is 2.8-6.0mm usually. The angle between the shunting cone 3 and the lower surface of the screw head 1 at the joint is 5-85 degrees, so that the flow of extruded materials in the screw rod 2 is subjected to shear deformation, and positive stress exists in the direction vertical to the shear direction to cause extrusion swelling. The angle between the lower surface of the tap head 1 and the tap cone 3 can be adjusted by changing the tap cone 3, so that the extrusion material is ensured to be continuously discharged through the discharge hole after passing through the inner cavity of the screw rod 2, and the extrusion expansion ratio can be conveniently adjusted.

The guide column 4 is in a regular cone shape, the bottom surface of the guide column is fixed on the upper surface of the screw head 1, the discharge hole is not shielded by the guide column 4, and the outer edge of the bottom surface of the guide column 4 is located on the inner side of the discharge hole. The inner diameter of the guide column 4 is set as required, and the maximum diameter is 2.8-6.0 mm. The angle between the flow guide column 4 and the upper surface of the screw head 1 at the connection position is 5-85 degrees. The flow guide column 4 is arranged outside the screw head 1, so that internal adhesion of each discharge hole can be prevented, and the middle hole is blocked.

Among the above-mentioned technical scheme, the fixed mode of reposition of redundant personnel awl 3 and guide post 4 does not have special restriction, this embodiment provides an optimal selection method, set up the recess promptly at the top surface of reposition of redundant personnel awl 3, the recess inner wall sets up the internal thread, guide post 4 is equipped with first through-hole along its self center pin, also correspond on the screwhead 1 and be equipped with the second through-hole, the nut card of fixed screw 5 is on the top of first through-hole, the screw pole of fixed screw 5 passes first through-hole and second through-hole in proper order, the internal thread cooperation of bottom external screw thread and reposition of redundant personnel awl 3 recess is screwed, fix the upper and lower surface at screwhead 1 respectively with reposition of redundant personnel awl 4 and reposition of redundant.

When the polypropylene hollow resin particle extrusion mechanism is used, extruded materials enter an inner cavity of a screw rod 2 through the bottom end of the screw rod 2, are shunted by the shunting cone 3 and are extruded from the discharge holes, the extruded materials of adjacent discharge holes swell and are bonded together, the angle formed at the joint of the shunting cone 3 and the lower surface of the screw head 1 can be adjusted by replacing the shunting cone 3, the uniformity of continuous discharge of the extruded materials through the discharge holes after passing through the inner cavity of the screw rod 2 is ensured, the extrusion swelling ratio can be conveniently adjusted, a hollow columnar filament is further formed, the guide column 4 can prevent the middle holes of the hollow columnar filament from being bonded, and the formed hollow columnar filament is in a shape similar to the arrangement of the discharge holes. The extrusion conditions are not limited, and the technicians in the field can control the extrusion conditions according to the actual needs according to the prior art, wherein the cooling water temperature is generally 10-30 ℃, and the distance between an extrusion mechanism and a cold water tank is 30-100 mm.

The polypropylene hollow resin particles of the present invention are produced by extrusion using a polypropylene hollow resin particle extrusion mechanism. The polypropylene hollow resin particles are cylinders, and the cross section of each cylinder is not in a perfect circle shape; the longest radial length of the cross section of the polypropylene hollow resin particle passing through the center is D, the shortest radial length of the cross section of the polypropylene hollow resin particle passing through the center is D, and D/D is more than or equal to 0.2 and less than 1.

The hollow expanded polypropylene beads of the present invention are obtained by expanding polypropylene hollow resin particles by a conventional foaming method. Usually, the foaming temperature is 140-150 ℃, the foaming pressure is 2.0-3.0MPa, the holding time is more than 5min, and the foaming ratio is 10-20 times.

The present invention is further illustrated by the following examples.