JP2014091320A - Screw for extrusion molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw for extrusion molding machines, which can extrude a molten resin from a metering section while promoting uniform distribution, dispersion, and kneading of the entire molten resin to obtain a homogeneous product.SOLUTION: The screw is constituted by arranging a feed section A of a resin, a compression section B, and the metering section C including a distributing/dispersing/mixing member 10. The distributing/dispersing/mixing member 10 is constituted so that a plurality of striped forwarding flights 12 or 22 are projected respectively on the outer peripheral surface of a base part side of a member body 1 and on that of a tip part side thereof at even intervals in the peripheral direction, a molten resin circulation groove 14 or 24 formed between the adjacent forwarding flights 12, 12 or between the adjacent forwarding flights 22, 22 is divided into a first inlet-side groove part 14a and a first outlet-side groove part 14b or a second inlet-side groove part 24a and a second outlet-side groove part 24b by an overflow flight 14 or 24, and a base end part of the forwarding flight 22 on the tip part side is disposed in the tip central part of the first outlet-side groove part 14b so that the molten resin is branched from the first outlet-side groove part 14b and the branched molten resin is merged in the second outlet-side groove part 24b.

Description

  The present invention relates to a screw used in a thermoplastic resin melt-extrusion molding machine.

  Conventionally, a screw used in this type of extrusion molding machine is provided with a raw material supply section, a compression section, and a metering section from a base end portion on the upstream side to a tip end portion on the downstream side, and a screw. A screw flight is provided on the outer peripheral surface of the shaft to feed the raw material downstream. This screw flight alone can actively melt the thermoplastic resin pellets (hereinafter referred to as solid resin). In addition, since it is difficult to uniformly stir and knead the molten resin, a screw having a mixing member for kneading and dispersing the molten resin in the measuring section has been developed.

  As such a mixing member, for example, as described in Patent Documents 1 and 2, the base end opens toward the upstream side and the tip end is closed on the outer peripheral surface of a cylindrical member body. Inflow grooves and outflow grooves whose base ends are closed and whose distal ends are open toward the downstream side are alternately provided in the circumferential direction, and between these inflow and outflow grooves, in the same spiral direction as the screw flight. It has a structure in which inclined main flights and subflights lower in height than the main flights are alternately provided in the circumferential direction, and after melting the solid resin, which is the raw material supplied to the supply section, in the compression section The molten resin is caused to flow into the inflow groove of the mixing member and melted when the molten resin is sent from the inflow groove to the outflow groove through the gap between the subflight and the barrel inner surface as the screw rotates. Kneading by applying shear stress to the fat, it is configured so as to promote melting and dispersion.

Japanese Patent Laid-Open No. 2001 212870 JP-A-6-218781

  However, according to the mixing member, when the molten resin sent from the compression unit side by screw flight is divided into a plurality of inflow grooves provided in the mixing member, the molten resin flows into one inflow groove. Will flow out from each outflow groove without mixing with the molten resin flowing into the other inflow grooves.For example, if the molten resin contains a pigment with poor dispersibility, If the ratio of the pigment in the molten resin that flows in differs from the ratio of the pigment in the molten resin that flows into the other inflow grooves, it will flow from the respective inflow grooves to the outflow groove side through the top surface of the subflight. Even if the pigment can be dispersed substantially uniformly in the molten resin, when the molten resin flows out from the respective outflow grooves and merges, the uniform dispersibility of the pigment throughout the molten resin is impaired. The quality of the goods will be reduced.

  Similarly, for example, when producing a sheet-like material of an ethylene-vinyl acetate copolymer resin (hereinafter referred to as EVA resin) containing an organic peroxide, when the EVA resin melts and plasticizes as the resin temperature increases. Since the organic peroxide is crosslinked to reduce the quality of the EVA resin, it is necessary to melt the EVA resin while suppressing the decomposition of the organic peroxide by lowering the resin temperature during molding. Therefore, in the state where fine unmelted material is mixed in the molten resin by the mixing member, it is sent out from the respective outflow grooves of the mixing member to the measuring unit side, but in the molten resin sent out from these outflow grooves It is difficult to disperse the unmelted material evenly, and when an EVA resin sheet is produced from the molten resin containing the unmelted material, a sheet portion where many unmelted materials are scattered is generated. , There is a problem that it is impossible to produce a homogeneous EVA resin sheet.

  In order to improve the dispersibility of the molten resin, it is conceivable to connect the mixing members in series. However, in such a structure, there is a possibility that the molten resin stays at the connection portion and the resin deteriorates. In addition, dispersibility can be improved without deteriorating the resin if a screw flight of an appropriate length is provided between the mixing members, but the length of the entire screw becomes longer and the extruder becomes larger. Problems arise.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to produce a homogeneous product by extruding the molten resin from the measuring section while promoting uniform distribution, dispersion, and kneading of the entire molten resin. It is in providing the screw for extruders which can be manufactured.

  In order to achieve the above-described object, the screw for an extruder according to the present invention includes, as described in claim 1, a supply portion from a base end side that is an upstream side of a screw shaft toward a distal end side that is a downstream side. In a screw for an extrusion molding machine in which a compression unit and a metering unit are sequentially provided, a distribution / dispersion mixing member for molten resin is disposed in the metering unit, and the distribution / dispersion mixing member is a cylindrical main body. A plurality of feed flights inclined in the rotational direction from the distal end side toward the proximal end side are provided on the outer peripheral surfaces of the base side and the front side of the base portion at predetermined intervals in the circumferential direction, and are adjacent to each other in the circumferential direction. In addition to forming molten resin flow grooves between the feed flights, the feed flight row on the front side is shifted in the groove width direction of the flow grooves with respect to the feed flight row on the base side, and Opposite each of these flow grooves at the center of the groove width direction of the tip A base end portion of the front-side feed flight is interposed, and a flow groove is formed between the upstream-side groove portion and the feed flight adjacent in the circumferential direction in the front-side feed flight row and the base-side feed flight row. It is characterized by being divided into a downstream groove portion and an overflow flight for allowing the molten resin to overflow from the upstream groove portion to the downstream groove portion.

  In the screw for an extrusion molding machine configured as described above, the invention according to claim 2 is characterized in that the front ends and the base ends of all the feed flights are formed at sharp ends.

  According to a third aspect of the present invention, a front portion of an overflow flight is continuously provided on a side wall surface of a front portion of a feed flight on a side preceding the rotation direction of a screw in a feed flight adjacent in the circumferential direction, and a base portion of the overflow flight is provided. Is connected to the side wall of the base portion of the feed flight facing the feed flight, and the overflow flight is inclined in the rotational direction from the distal end side to the proximal end side with an inclination angle smaller than the inclination angle of the feed flight. The upstream groove portion of the flow groove divided by the overflow flight is formed into a planar triangular groove portion whose groove width gradually decreases from the base end to the tip end, while on the downstream side The groove portion is formed into a planar triangular groove portion whose groove width gradually increases from the base end to the tip end.

  Furthermore, in the invention according to claim 4, the top surface of the overflow flight is inclined so that its height decreases toward the one side end edge facing the rotation direction of the screw over the entire length of the top surface. It is formed on the surface.

  According to the first aspect of the present invention, the distribution / dispersion mixing members disposed in the metering unit for kneading and dispersing the molten resin in the screw for the extruder are the base side and the front side of the cylindrical main body. A plurality of feed flights inclined in the rotational direction from the front end side to the base end side are projected on the outer peripheral surface of the outer peripheral surface at predetermined intervals in the circumferential direction and the base side The leading edge side of the feeding flight row is shifted in the groove width direction of the circulation groove formed between the neighboring adjacent feeding flights in the circumferential direction, and the groove width at the tip of each circulation groove on the base side A proximal end portion of the forward flight that is opposed to each of the flow grooves is interposed at the center of the direction, and is adjacent to the circumferential direction in the forward flight train and the proximal flight train. Between the sending flights, the distribution groove is located upstream and downstream. In addition, an overflow flight is provided that bisects the molten resin from the upstream groove to the downstream groove. The molten resin to be fed is shunted into the flow grooves between adjacent feed flights in the feed flight row projecting on the base side outer peripheral surface of this member body, and the overflow flight and barrel provided in each flow groove The molten resin can be effectively kneaded and dispersed while the unmelted resin contained in the molten resin is crushed by the shearing force generated by the overflow flight and the barrel through the gap between the two.

  Furthermore, the molten resin that has passed through each of the flow grooves on the base side of the member body is sent to the flow grooves between adjacent feed flights in the feed flight train on the front side by the feed flight, but the feed flight train on the base side On the other hand, the feed flight train on the front side is shifted in the groove width direction of the flow grooves, and the feed on the front side facing the flow grooves is centered in the groove width direction at the tip of each flow groove on the base side. Since the base end portion of the flight is interposed, the outlet of one flow groove on the base side communicates in a state of branching to the inlet of the adjacent flow groove on the front side provided on the downstream side of the flow groove. Thus, the molten resin fed from the flow groove on the base side can be fed while being distributed to the two flow grooves on the front side, and accordingly, the adjacent flow grooves provided on the base side of the member body are respectively Dispersed and kneaded while passing The molten resin can be merged from these flow grooves into one flow groove provided on the front side of the member body, and the overflow is provided in the flow groove while passing through the flow groove on the front side. It is further sheared, kneaded and dispersed by the flight, so that the entire molten resin can be extruded from the member body so as to be as uniformly kneaded and dispersed as possible, and an excellent quality product can be manufactured.

  Further, according to the invention according to claim 2, since the tip and the base end of all the feeding flights are formed at the sharp end, the distribution / dispersion mixing member can be smoothly distributed without retaining the molten resin. , Can be passed.

  According to the third aspect of the present invention, the overflow part is continuously provided on the side wall surface of the front part of the feed flight on the side preceding the rotational direction of the screw in the feed flight adjacent in the circumferential direction. Of the upstream side of the flow groove divided by the overflow flight, the groove width is gradually narrowed from the base end to the front end. On the other hand, since the groove portion on the downstream side is formed in the flat triangular groove portion whose groove width is gradually increased from the base end to the tip end, the groove portion on the downstream side is formed from the compression portion side. The supplied molten resin can smoothly flow into the upstream groove, and the resin pressure generated in the groove can overcome the overflow flight and disperse the molten resin into the downstream groove. In addition, since the overflow flight is sent and tilted in the direction of rotation from the tip side to the base end side with an inclination angle smaller than the inclination angle of the flight flight, the molten resin is slanted on the overflow flight. It can be made to pass across, and a passing distance becomes long, and the dispersion | distribution of a molten resin and the kneading | mixing effect can be improved further.

  Furthermore, according to the invention which concerns on Claim 4, the top surface of the said overflow flight is inclined so that height may become low toward the one side edge which has turned the top surface to the rotation direction of a screw over the full length. Therefore, the molten resin can flow from the upstream groove to the downstream groove while smoothly riding on the top surface of the overflow flight. As it passes through the surface, the shearing force by the opposing surface of the top surface and the barrel increases, and the unmelted resin contained in the molten resin can be reliably ground.

The simplified side view of the screw for extrusion machines of the present invention. The enlarged side view of the principal part. The perspective view of a distribution and dispersion | distribution mixing member. The side view. The developed view. X1-X1 sectional view taken on the line in FIG. X2-X2 sectional view taken on the line in FIG.

  Next, a specific embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the screw for the extruder is rotatably disposed in the barrel 4 and is downstream from the base end side, which is the upstream side. A supply unit A, a compression unit B, and a measuring unit C are sequentially provided toward the distal end side that is the side. The supply part A has a main flight 2 projecting from the outer peripheral surface of the base of the screw shaft 1 and the diameter of the base of the screw shaft 1 is smaller than the diameters of the screw shafts of the compression part B and the measuring part C. The compression part B is composed of a main flight 2 continuous from the supply part A side on the outer peripheral surface in the longitudinal direction of the screw shaft 1 and a subflight whose outer diameter is smaller than that of the main flight 2. 3 is arranged side by side in a continuous spiral along the main flight 2, and the metering section C distributes and disperses the main flight 2 and the molten resin that are continuous from the compression section B side to the outer peripheral surface of the front end of the screw shaft 1. A mixing member 10 and a flight 2 ′ extending from the distributing / dispersing mixing member 10 to the tip of the screw shaft 1 are provided. The flight 2 'is formed to have the same diameter as the main flight 2.

  The structure of the distribution / dispersion mixing member 10 provided in the measuring unit C will be described in detail. As shown in FIGS. 2 to 4, the distribution / dispersion mixing member 10 has a shaft diameter of the measuring unit C in the screw shaft 1. Is inclined in the rotational direction of the screw shaft 1 from the distal end side toward the proximal end side on the outer peripheral surface of the base portion corresponding to one half (second half portion) in the length direction of the cylindrical member body 11 having an outer diameter equal to A plurality of feed flights 12, 12... 12 are formed between a base-side feed flight train formed by protruding at regular intervals in the circumferential direction, and between adjacent feed flights 12, 12 in the base-side feed flight train. The flow grooves 14 are arranged upstream of the spiral flow grooves 14 having a constant width and the opposite inclined side wall surfaces of the adjacent sending flights 12 and 12 in the length direction. Groove portion (hereinafter referred to as first inlet-side groove portion 14a) and downstream groove portion ( Hereinafter, the overflow flight 13 is divided into the first outlet side groove portion 14b).

  Similarly, a plurality of strips inclined in the rotational direction of the screw shaft 1 from the distal end side toward the proximal end side are provided on the outer peripheral surface of the tip portion corresponding to the other half portion (front half portion) in the length direction of the member body 11. Formed between the leading part side flight flight line formed by projecting the feeding flights 22, 22... 22 at regular intervals in the circumferential direction, and each adjacent sending flight 22, 22 in this leading part side feeding flight line. A spiral distribution groove 24 having a constant width and both end portions in the length direction are integrally connected to the opposing inclined side wall surfaces of the adjacent feeding flights 22 and 22 so that the distribution groove 24 is upstream of the groove section. An overflow flight 23 that is divided into two (hereinafter referred to as a second inlet side groove portion 24a) and a downstream groove portion (hereinafter referred to as a second outlet side groove portion 24b) is provided.

  Further, with respect to the base side feed flight row projecting on the base outer peripheral surface of the member body 11, the front side feed flight row is arranged in the circumferential direction of the member body 11 by a half of the groove width of the flow groove 14. Is disposed at a position shifted by a distance corresponding to, and a tip of each flow groove 14 on the base side facing the flow grooves 14 at the center in the groove width direction at the tip of the first outlet groove 14b. The molten resin delivered from the first outlet side groove 14b is divided into two parts by the proximal end of the front-side feed flight 22 by interposing the base end portion of the feed-side flight 22 on the part side. 2 The diverted molten resin is divided into the inlet side grooves 24a, 24a, and the divided molten resin flows from the first outlet side groove 14b of the flow groove 14 adjacent to the flow groove 14 through which the molten resin flows, to the base of the feed flight 22 on the front side. One second inlet side groove 2 on the front side together with the molten resin that is divided into two by the end It is configured to join 4a.

  All the feed flights 12, 22 constituting the base side feed flight row and the front side feed flight row are formed in the same size, the same shape, and an elongated rectangular bar shape, and the base side feed flight 12 is The member main body 11 that is disposed at the center in the length direction of the member main body 11 at one end in the length direction and rotates integrally with the screw shaft 1 from the tip end toward the base end. The base end portion is disposed on the outer peripheral surface of the base end portion of the member main body 11.

  On the other hand, the feed flight 22 disposed on the front side of the member main body 11 has a distal end portion, which is one end portion in the length direction, integrally provided on the outer peripheral surface of the distal end portion of the member main body 11, and this front end portion. The base body 11 that rotates integrally with the screw shaft 1 from the base end to the base end is inclined at the same inclination angle as that of the feed flight 12 on the base side, and the base end of the feed flight 22 is inclined. Arranged at the center of the member main body 11, the intermediate portion between the tip ends of adjacent feed flights 12, 12 in the base side feed flight row, that is, the above formed between the feed flights 12, 12. The base end portion is interposed at the center portion in the groove width direction at the distal end portion of the first outlet side groove portion 14b of the flow groove 14, and the outlet of the flow groove 14 is branched to both sides.

  The radius from the center of the screw shaft 1 to the top surfaces of the feed flights 12, 22 is the same as the main flight 2, with the top surface slidingly contacting the inner surface of the barrel 6 or having a slight gap from the inner surface. The molten resin is fed to the downstream side by the feed flights 12 and 22 as the screw shaft 1 rotates.

  In addition, one side wall surface facing the rotation direction at the tip of all the feeding flights 12, 22 is formed into inclined side wall surfaces 12a, 22a that gradually taper toward the tip, and the tip is formed at a sharp end. doing. Similarly, the other side wall surfaces facing in the opposite direction to the rotation direction at the base end portions of all the feeding flights 12 and 22 are formed on the inclined side wall surfaces 12b and 22b that gradually taper toward the base end. The base end is formed as a sharp end. By taking the inclination angle of these inclined side wall surfaces 12a, 22a and 12b, 22b with respect to the length direction of the screw shaft 1 to about 45 degrees, the molten resin can be taken into the flow groove 14 and the flow grooves 14, 24 It is configured so that the molten resin can flow and pass smoothly.

  The overflow flight 13 which bisects the flow groove 14 into a first inlet side groove 14a and a first outlet side groove 14b, and the flow groove 24 is divided into a second inlet side groove 24a and a second outlet side groove 24b. As shown in FIGS. 6 and 7, the overflow flight 23 is formed in the shape of an elongated rectangular bar whose height is lower than that of the feed flights 12 and 22, and the top surface is screwed over the entire length. Inclined top surfaces 13a and 23a are formed so as to be lowered toward one end edge facing the rotation direction of the shaft 1, and molten resin is formed on the inclined top surfaces of the overflow flights 13 and 23. The first and second inlet side grooves 14a and 24a flow through the gap between the surfaces 13a and 23a and the inner peripheral surface of the barrel 4 to the first and second outlet side grooves 14b and 24b, respectively. The fine unmelted material contained in the molten resin is caused by the shear stress at the opposite surface between the overflow flights 13 and 23 and the barrel 4. While crushing Ri, causes melted by shearing heat generated by friction with the barrel 4, distribute the molten resin, and configured to kneading.

  Further, these overflow flights 13 and 23 are formed so that one side part facing the rotation direction at the tip part is formed in a tapered shape, and the one side wall surface is fed on the side preceding the rotation direction of the screw shaft 1. The other side portions of the front portions of the flights 12 and 22 that are integrally connected to the other side wall surfaces facing in the opposite direction with respect to the rotation direction and the other side portions of the base portion facing in the opposite direction with respect to the rotation direction The other side wall surface is formed into a tapered shape and is integrated with one side wall surface facing the rotation direction at the base of the feed flights 12 and 22 facing the feed flights 12 and 22 in the direction opposite to the rotation direction. And the angle of inclination of these overflow flights 13 and 23 with respect to the longitudinal direction of the screw shaft 1 from the distal end side with an inclination angle smaller than the inclination angle of the feed flights 13 and 23. Turn to the side It is inclined in the direction.

  The first and second inlet-side grooves 14a and 24a in the distribution grooves 14 and 24 divided into two by the overflow flights 13 and 23 are flat surfaces in which the groove width is gradually narrowed from the base end side toward the tip end. On the other hand, the first and second outlet side groove portions 14b and 24b are formed in a planar triangular groove portion whose groove width gradually increases from the base end side toward the tip end. .

  Next, the operation of the screw for an extruder of the present invention provided with the distribution / dispersion mixing member 10 configured as described above will be described. Solid resin as a raw material supplied to the supply section A through a hopper (not shown) Is transferred to the compression section B side by the main flight 2 as the screw shaft 1 rotates, and heat transfer from the barrel 4 side during the transfer, frictional heat between the inner surface of the barrel 4 and shearing action between the resins. It is sent to the compression section B while starting melting due to heat generation.

  While passing through the compression portion B, a molten resin layer is formed on the portion in contact with the inner surface of the barrel 4, and the molten resin layer passes over the subflight 3 and the subflight 3 and the back surface of the subflight 3. It flows into the groove 5 between the main flight 2 on the side. The subflight 3 is spirally wound around the screw shaft 1 so that the width of the groove portion 5 increases toward the tip of the compression portion B. Therefore, molten resin that gradually increases while passing through the compression portion B is removed. 5 is fed into the measuring section C while being accommodated in the inside.

  The molten resin sent to the measuring section C is sent to the distribution / dispersion mixing member 10 by the main flight 2 and each adjacent sending flight provided on the outer peripheral surface of the base side of the member main body 11 of the distribution / dispersion mixing member 10. It flows into the first inlet-side groove 14a between 12 and 12. Since the first inlet side groove portion 14a is formed in a planar triangular shape that becomes narrower as it goes downstream, the resin pressure of the molten resin flowing into the first inlet side groove portion 14a increases as it goes downstream. As the distribution / dispersion mixing member 10 that rotates integrally with the screw shaft 1 rotates, the resin pressure causes the inclined top surface 13a of the overflow flight 13 to cross over the length of the member main body 11 diagonally. It flows into the first outlet side groove 14b.

  At this time, the gap between the inclined top surface 13a of the overflow flight 13 and the inner peripheral surface of the barrel 4 is a wedge-shaped gap that narrows in the opposite direction to the rotation direction of the distribution / dispersion mixing member 10. Therefore, the unmelted resin contained in the molten resin is melted by shearing heat generated by friction with the barrel 4 while being reliably ground with a large shearing force, and from the overflow flight 13 to the first outlet side groove portion. The molten resin can be allowed to flow while being dispersed and kneaded into 14b, and the first outlet side groove 14b is formed so as to gradually become wider toward the outlet on the front end side of the groove. The molten resin is further uniformly diffused and kneaded while passing through the outlet side groove 14b.

The molten resin flows in the first outlet side groove 14b toward the downstream side, and the first outlet side groove 14b.
When the leading end of the first outlet side groove 14b is reached, the feeding flight 22 in the leading portion side feeding flight row on the leading end side, which is the other half of the length direction of the member main body 11, is provided at the center of the leading end portion of the first outlet side groove portion 14b. Therefore, the molten resin pushed forward by the inclined side wall surface of the feed flight 12 according to the rotation of the distribution / dispersion mixing member 10 has the downstream side as shown by the arrow in FIG. The second inlet side groove in the front side flow groove 24 distributed by the base end portion of the front side feed flight 22 and provided on both sides of the front side feed flight 22 when flowing out from the first outlet side groove portion 14b. Part 24a
To 24a. The distribution and distribution of the molten resin are performed on the molten resin sent out from the first outlet side grooves 14b of all the flow grooves 14 provided on the base side.

  At this time, the molten resin is diffused and kneaded as described above while passing through the first inlet side groove portion 14a that gradually becomes wider as it goes to the front end side. When being divided into two, the first outlet side groove 14b between the both side surfaces of the base end portion of the leading side feed flight 22 and the side surfaces of the base side feed flights 12, 12 opposite to the both side surfaces of the base end portion Since the width of the tip outlet is narrowed, the molten resin is compressed and more uniformly kneaded while passing through this tip outlet portion divided into two by the front-side feed flight 22.

One molten resin from the first outlet side groove portion 14b diverted by the base end portion of the front portion side feed flight 22 has a first flow groove adjacent to one side of the flow groove 14 through which the molten resin flows. The first outlet side groove 14b communicates with the second molten resin divided at the base end of the front-side feed flight 22 at the distal end of the first outlet-side groove 14b. Inlet side groove 24a
Similarly, the other molten resin from the first outlet side groove 14b divided by the base end portion of the front-side feed flight 22 enters the other side of the flow groove 14 through which this molten resin flows. A tip part of the first outlet side groove part 14b of the adjacent outlet groove 14 communicates with one of the molten resins divided at the base end part of the front part side feed flight 22 and the first outlet side groove parts 14b, 14b communicate with each other. The molten resin that has merged into the second inlet side groove portion 24a of the side flow groove 24 and fed from the adjacent upstream flow grooves 14 and 14 is mixed and dispersed more uniformly.

  Further, while the molten resin merged into the second inlet side groove 24a in each of the flow grooves 24 on the front side passes through the second inlet side groove 24a, the second inlet side groove 24a becomes the first inlet side groove. Since it is formed in a plane triangle shape that becomes narrower as it goes downstream as in 14a, rotation of the distribution / dispersion mixing member 10 that rotates integrally with the screw shaft 1 while increasing its resin pressure toward the downstream side As a result, the air travels over the inclined top surface 23a of the overflow flight 23 while obliquely crossing in the length direction of the member body 11, and flows into the second outlet side groove 24b.

At this time, the gap between the inclined top surface 23a of the overflow flight 23 and the inner peripheral surface of the barrel 4 is the same as that of the overflow flight 13 provided on the base side feed flight train side. Since it is formed in a wedge-shaped gap narrowing in the opposite direction with respect to the rotation direction of 10, the friction with the barrel 4 while reliably grinding the unmelted resin contained in the molten resin with a large shearing force The molten resin can be melted by the shear heat generated by the air flow, and the molten resin can be introduced from the overflow flight 23 into the second outlet side groove 24b while being dispersed and kneaded. Further, the second outlet side groove 24b
However, since it is formed so that it gradually becomes wider as it goes to the outlet on the front end side of the groove part, the molten resin is more uniformly diffused and kneaded while passing through the first outlet side groove part 14b, and the second outlet side groove part 24b. From the tip of the screw to the tip of the measuring unit C, and is supplied to the die with a predetermined pressure from the tip of the screw by flight 2 ′.

  In the embodiment described above, the number of feed flights 12 and 22 is six, but it is desirable to provide 3 to 20, preferably 6 to 12. When the number of feed flights 12 and 22 is small, the distribution action of the molten resin is small, so the temperature distribution is deteriorated and the dispersibility is also reduced. As a result, the residence time of the molten resin is increased, and as a result, there is a possibility of adversely affecting the reactive resin and the easily deteriorated resin.

A Supply part B Compression part C Weighing part 1 Screw shaft 2 Main flight 3 Subflight 4 Barrel 5 Groove part
10 Distributing / dispersing mixing parts
11 Material body
12, 22 feed flights
13, 23 Overflow flight
14, 24 Distribution channel
14a 1st inlet side groove
14b First outlet side groove
24a Second inlet side groove
24b Second outlet groove

Claims (4)

  Distributing molten resin to the metering unit in an extrusion machine screw in which a supply unit, a compression unit, and a metering unit are sequentially provided from the base end side, which is the upstream side of the screw shaft, to the tip side, which is the downstream side. A dispersion / mixing member is provided, and the distribution / dispersion mixing member is inclined in the rotational direction from the distal end side toward the proximal end side on the outer peripheral surface of the base side and the front end side of the cylindrical main body. A plurality of feed flights are provided at predetermined intervals in the circumferential direction to form molten resin flow grooves between adjacent feed flights in the circumferential direction, and a leading portion with respect to the feed flight train on the base side The base end of the forward flight of the front side facing the respective flow grooves at the center in the groove width direction of the front end of each flow groove by shifting the feed flight row on the side in the groove width direction of the flow grooves A front side flight flight line and a base part. Between the feed flights adjacent in the circumferential direction in the feed flight train, the flow groove is divided into an upstream groove portion and a downstream groove portion, and the molten resin is allowed to overflow from the upstream groove portion to the downstream groove portion. A screw for an extrusion molding machine, wherein a flow flight is provided.   The screw for an extrusion molding machine according to claim 1, wherein a tip end and a base end of the feed flight are formed at a sharp end.   In the feed flight adjacent to the circumferential direction, the front part of the overflow flight is connected to the side wall of the front part of the feed flight on the side preceding the rotational direction of the screw, and the base of this overflow flight is opposed to the feed flight. This overflow flight is connected to the base side wall surface of the flight and is inclined in the rotational direction from the distal end side to the proximal end side with an inclination angle smaller than the inclination angle of the sending flight. The upstream groove portion of the flow groove divided by two is formed into a planar triangular groove portion whose groove width gradually decreases from the base end toward the tip, while the downstream groove portion extends from the base end to the tip. The screw for an extruder according to claim 1, wherein the screw is formed in a planar triangular groove portion having a groove width gradually increased.   The top surface of the overflow flight is formed into an inclined top surface that is inclined so that the height decreases toward the one side edge that faces the rotation direction of the screw over the entire length of the top surface. The screw for an extruder according to claim 1 or 3.

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