Rotation extrusion processing rheometer and rheological measuring method capable of simultaneously measuring pressure/shear rheology of polymers

Abstract

A rotating extrusion rheometer includes a control monitoring mechanism, a melt extrusion mechanism, a rotating extrusion rheology machine head, a sensor, a drive chain wheel, a coupler and an electric motor. The control monitoring mechanism, the melt extrusion mechanism, the rotating extrusion rheology machine head are sequentially connected. The rotating extrusion rheology machine head is formed by a connecting pipe (1), a flow dividing support (3), a lower machine neck (12), a machine head piece (15), an opening mold (17), an opening-mold driving chain wheel (20), a core bar (21) and a core-bar driving mechanism. The rheology measurement method comprises the steps where some parameter values of the rheometer are collected first, and then the rheological behaviors of the polymer melt in the rotating extrusion process are obtained by performing calculation by means of using the derived formula.

Claims

1. A rotation extrusion processing rheometer capable of simultaneously measuring polymer pressure/shear rheology includes melt extrusion system, rotation extrusion rheometer machine head, sensor and transmission sprocket, coupling, motor and monitoring mechanism, which are connected in sequence. This rheometer is characterized by the following mentioned features. The rotation extrusion rheological machine head is composed of connecting pipes (1), the shunt bracket (3), lower neck section (12), machine head piece (15), die (17), die driving sprocket (20), mandrel (21) and mandrel driving mechanism. The connecting pipe piece (1), shunt bracket (3) and head piece (15) are in turn to connect as a whole by adapting pieces. The lower neck section (12) is located in the cavity between the shunt bracket (3) and the machine head piece (15). The die (17) is movably fixed to the cavity behind the machine head piece (15) and connected with the die driving sprocket (20) outside the end face of the machine head piece (15). The mandrel (21) is located in the channel formed by lower neck section (12), the machine head piece (15) and the die (17). One end of the mandrel is connected to the mandrel driving mechanism located in the shunt bracket (3). The sensors are divided into pressure sensors and torque sensors. The pressure sensor is placed in the stepped through hole (16) on the side of the machine head piece (15), The torque sensor is installed on the coupling between the driving sprocket and the motor. Both of the pressure sensor and torque sensor are connected to the control and monitoring mechanism.

2. The rotation extrusion processing rheometer according to claim 1, characterized in that the cross-sectional shape of the connecting pipe piece (1) is an inverted “convex” shape. Both the left and right end faces are flange plates. The melt feeding through hole (2) is opened in the middle of the left disk surface connected to the melt extrusion mechanism. The second half of the feeding through hole (2) is a horn shaped open cavity to connect with the inverted tapered protrusion at one end of the shunt bracket (3).

3. The rotation extrusion processing rheometer according to claim 1, characterized in that the front part of the frame of the shunt bracket (3) is an inverted cone-shaped protrusion. The middle part of the frame has a flange plate formed by extending outwards along the base of an inverted cone-shaped protrusion and thus the flange plate is matched and connected with the connecting pipe piece and the machine head piece. The side of the frame between the two flanges extends downward to form a column (4). The outer diameter of the back frame is smaller than that of the middle frame and matched with the inner diameter of the stepped through hole at the front end of the lower machine section (12); The outer surface of the inverted cone-shaped protrusion is provided with an arc “concave” groove melt material flow channel (5). There is a convex rib (6) every two arc “concave” groove melt material flow channel (5); There is a stepped blind hole (7) horizontally opened at the middle and rear part of the shunt bracket (3). A stepped through hole (8) is opened in the column (4) which lies below the middle section of the frame of the shunt bracket (3). The stepped through hole (8) is vertically connected to the blind end of the stepped blind hole (7) and the other end is sealed by a cover plate (9) with a hole around it; An air hole (10) is opened on the middle section frame (6) which is located on the upper side of the raised rib and (10) is also connected with the blind end of the stepped blind hole (7).

4. The rotation extrusion processing rheometer according to claim 1, characterized in the features that the lower neck section (12) is like a cylindrical cone with a stepped through hole in it.

5. The rotation extrusion processing rheometer according to claim 1, characterized in that the machine head piece 15 is a cylinder, one end of which is a flange plate connected to the shunt bracket (3). The front and middle sections of the cylinder are provided with a cylindrical funnel-shaped open cavity along the axial direction. A stepped through hole (16) is vertically opened on the cylinder on the side of the starting end of the funnel cavity nozzle. A cylindrical open cavity is opened along the axial direction in the cylinder at the rear of the stepped through hole 16. There is a convex cone at the bottom of the cavity and the axial hole in the cone is the extension section of the funnel-shaped cavity nozzle.

6. The rotation extrusion processing rheometer according to claim 1, characterized in that the die 17 is an inverted “T”-shaped cylindrical body with a “T”-shaped stepped through hole in axial direction. This cylindrical body is movably fixed in the cylindrical open space of the nose body 15 by a tapered bearing 18 and a nut 19.

7. The rotation extrusion processing rheometer according to claim 1, characterized in that the mandrel 21 is a glassy bar, which is formed by a supporting movable fixed section and a working section. The supporting movable fixed section is movably supporting fixed by axletree 13, formed in the stepped cavity between the shunt bracket 3 and the lower machine neck 12. This makes the working section cantilever locate in the stepped through hole of the funnel nozzle of the machine head piece 15 and the die 17. The working section is composed of a conical section and a straight section and the length ratio of the conical section to the straight section is at least 11:1. An annular groove 22 is opened at the junction of the supporting movable fixed section and the working section in this example. In addition, an axial vent hole 23 is opened along the mandrel 21.

8. The rotation extrusion processing rheometer according to claim 1, characterized in that the mandrel driving system is composed of driving rod of the core bar 24, bevel gear 25 and a bearing 26. The driving rod of the core bar 24 is in turn to cross through the stepped through hole 8 of the column 4 under the middle section of the shunt bracket 9 and the through hole cover 9. The driving rod of the core bar 24 is movably supported and fixed by the bearing 26 which is located in the stepped through hole so that the upper end of the driving rod is located in the blind end cavity of the middle section of the shunt bracket 3 and the lower end is located outside the nether column 4 to connect with the mandrel drive sprocket 27. There are two bevel gears 25. One is installed on supporting active fixed segment of the mandrel 21 in the middle cavity of the shunt bracket 3. The other is geared with the mandrel and installed on top end of one end of driving rod of the core bar 24, located in the middle cavity of the shunt bracket 3.

9. The rotation extrusion processing rheometer according to claim 1, characterized in that the melt feeding through hole (2) lie on the same center line with the mandrel (21); There are three arc-shaped “concave” groove melt flow channels (5) and the width of the feeding end is larger than that of the discharging end; The rheometer is also equipped with a cooling box, a traction and a coiler after the rotating extrusion rheological head machine to make the extruded melt into polymer microtubes.

10. A rheological measurement method capable of simultaneously measuring polymer pressure/shear rheology is characterized by the features that the rheological measurement method includes the following steps: 1) Collect the pressure value ΔP, the mandrel torque value M2 and the die torque transmitted to the control and monitoring mechanism according to the pressure sensor and the torque force sensor of the rotary extrusion process rheometer according to claim 1 Force value M 2) The axial strain rate (γr) is calculated by the following formula:
σrz=ΔPR024L−2rR02+−2rR02+[1−RiR02]2lnR0Ri1r The axial stress (σrz) is calculated by the following formula:
γγz=2QΠR21−RiR04−1−RiR022lnR0Ri−2rR02+1−RiR022lnR0Ri1r The hoop strain rate (γ) is calculated by the following formula:
γr0=Ω1(1r2−1R0)1Ri2−1R0+Ω2(1r+1Ri2)1Ri2−1R0 The hoop stress (σrδ) is calculated by the following formula:
σrθ=M1±M22Πr2L=A1(M1±M2)r2 In these equations, R0, Ri and r represent outside, inside and any position of radius of molding runner, respectively. L is length of molding runner and Q is extruding flow. Ω1 and Ω2 mean die and mandrel rotating rate, respectively. If the curtain index is 1, combined shearing stress, shearing rate and melt viscosity are obtained: The obtained combined shearing stress and combined shearing rate are the rheological parameters under complicated pressure/multi-shearing field, capable of providing research basis and practical processing guidance for rheological behavior, structure formation and evolution of polymers under complex pressure/multi-shearing field.

Description

DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a schematic diagram of the structural connecting relationship of the rotary extrusion rheometer capable of simultaneously measuring polymer pressure/shear rheology according to an embodiment of the present invention;

[0040] FIG. 2 is a cross-sectional structure diagram of the rotation extrusion rheometer head in the rotation extrusion rheometer capable of simultaneously measuring polymer pressure/shear rheology according to an embodiment of the present invention;

[0041] FIG. 3 is a schematic cross-sectional structure diagram of the shunt bracket in the rotation extrusion rheometer head of the rotation extrusion rheometer capable of simultaneously measuring polymer pressure/shear rheology according to an embodiment of the present invention;

[0042] FIG. 4 is a schematic left view of the structure of FIG. 3;

[0043] FIG. 5 is a schematic cross-sectional structure diagram of the mandrel in the rotation extrusion rheological head of the rotation extrusion rheometer capable of simultaneously measuring polymer pressure/shear rheology according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those ordinary technicians without creative work shall fall within the protection range of the present invention.

Example 1

[0045] This embodiment is an embodiment of the rotation extrusion processing rheometer capable of simultaneously measuring the pressure/shear rheology of polymers.

[0046] The polymer rotation extrusion processing rheometer with rheological measurement function provided in this embodiment includes the melt extrusion mechanism, the rotation extrusion rheological head, and the sensor, the transmission sprocket, the coupling, motor, the control and monitoring institutions, the cooling boxes, the tractors and the tube coilers, etc. which are sequentially connected, as shown in FIG. 1. Among them, the rotation extrusion rheological head is composed of the connecting pipe fitting 1, the shunt bracket 3, the lower neck section 12, the machine head piece 15, the die 17, the die driving sprocket 20, the mandrel 21 and the mandrel driving mechanism. The connecting pipe fitting 1, the shunt bracket 3, and the machine head piece 15 are connected in order by a uniformly distributed connecting piece, such as the bolt 11 and the screw thread. The lower neck section 12 is located in the cavity between the shunt bracket 3 and the machine head piece 15. The die 17 is active fixed in the cavity at the rear end of the machine head piece 15, and is connected to the opening mold driving sprocket 20 outside the end face of the machine head piece 15. The mandrel 21 is located in the inner channel of the lower neck section 12, the machine head piece 15 and the die 17, with one end connected to the mandrel driving mechanism in the shunt bracket 3. The sensors are divided into pressure sensor and torque sensor. The sensor is installed in the stepped through hole 16 on the side of the machine head piece 15, and the torque sensor is installed on the coupling between the transmission sprocket and the motor. Both sensors are connected to the control and monitoring mechanism The cooling box, the tractor, the coil machines and other equipment are connected outside the die 17 in sequence.

[0047] The cross-sectional shape of the connecting pipe fitting 1 is an inverted “convex” shape, the left and right ends are both flange plates, and the middle of the left plate surface connected to the melt extrusion mechanism is opened with a melt feeding through hole 2 The melt feeding through hole 2 and the mandrel 21 are located on the same center line, and the rear half of the feed through hole 2 is an open cavity with a bell mouth to match the conical protrusion at one end of the shunt bracket 3, as shown in FIG. 2.

[0048] The front section of the frame of shunt bracket 3 is an inverted conical protrusion, and the middle section of the frame has a flange plate extending outward along the bottom edge of the inverted conical protrusion which is matched and connected with the connecting pipe fitting and the machine head piece. The side of the frame between the flange plate surfaces extends downward to form a column 4, the outer diameter of the rear frame is smaller than the outer diameter of the middle frame and matches with the inner diameter of the stepped through hole at the front end of the lower neck section. The outer surface of the inverted cone-shaped protrusion is provided with an arc-shaped “concave” trough melt material flow channel 15. In this embodiment, there are three arc-shaped “concave” trough melt material flow channels that are s, and the melt material flow channels 5 extend to the end of the middle section frame, and the width of the feeding end is greater than the width of the discharging end. Every two arc-shaped “concave” trough melt material flow channels 5 are separated by a convex reinforce 6. A stepped blind hole 7 is horizontally opened in the middle and rear section of the frame of shunt bracket 3, and the cavity on the side of the blind end is used as the transmission chamber where the arc gear 25 is located which meshed in the mandrel driving mechanism. A stepped through hole 8 is opened in the column 4 extending below the middle section of the frame. The stepped through hole 8 is vertically connected to the blind end of the stepped blind hole 7, and the other end is sealed by a cover plate 9 with a hole. In addition, a vent hole 10 is also opened on the middle section of the frame of the rib on the upper side. The vent hole 10 is also connected with the blind end of the stepped blind hole 7, so that the pressured gas is allowed to enter the axial vent hole 23 opened in the mandrel 21 to reach the microtube at the end of the outlet die 17. On the one hand, it can cool down the newly extruded pipe, and on the other hand, it can prevent the melt collapse of the newly extruded pipe. As shown in FIG. 2-4.

[0049] The shape of the lower neck section 12 likes a columnar cone with a stepped through hole inside. After the rear section of the shunt bracket is matched with the stepped through hole, a pair of bearings 13 and a separation washer 14 are placed in it. Shown in FIG. 2.

[0050] The machine head piece 15 is a cylinder, one end of which is a flange plate connected to the shunt bracket 3. The front and middle sections of the cylinder are provided with a cylindrical funnel-shaped open cavity along the axial direction. The machine neck section 12 is matched with the cavity and placed in it. A gap is left between lower machine neck 12 and the inner wall of the cavity to serve as a flow channel behind the frame of shunt 3 for the melt. A stepped through hole 16, in which a pressure sensor is arranged, is vertically opened on the cylinder on the side of the starting end of the funnel cavity nozzle. A cylindrical open cavity is opened along the axial direction in the cylinder at the rear of the stepped through hole 16. There is a convex cone at the bottom of the cavity and the axial through hole in the cone is an extension of the funnel-shaped cavity nozzle. The middle of funnel-shaped cavity and inner wall of its extension are matched with the first half of conical section of the working section of the mandrel 21, There is also a gap between them to serve as the melt flow channel connected to the lower neck section 12. See FIG. 2.

[0051] The die 17 is an inverted “T”-shaped cylindrical body with a “T”-shaped stepped through hole along axial direction. This cylindrical body is movably fixed in the cylindrical open space of the machine head piece 15 by a tapered roller bearing 18 and a nut 19. The die 17 is matched with the tapper second half of the working section and the straight section of the mandrel 21. There is also a gap between them to serve as a flow channel for the melt connected to the machine head piece 15. See FIG. 2.

[0052] The die driving sprocket 20 is connected with transmission sprocket, coupling and motor through a chain.

[0053] The mandrel 21 is a glossy bar, which is formed by a supporting movably fixed section and a working section. The supporting movably fixed section is movably supporting fixed by axletree 13, formed in the stepped cavity between the shunt bracket 3 and the lower machine neck 12. This makes the working section cantilever locate in the stepped through hole of the funnel nozzle of the machine head piece 15 and the die 17. The working section is composed of a conical section and a straight section and the length ratio of the conical section to the straight section is at least 11:1. An annular groove 22 is opened at the junction of the supporting movable fixed section and the working section in this example. In addition, an axial vent hole 23 is opened along the mandrel 21. See FIG. 2 and FIG. 5.

[0054] The mandrel driving system is composed of driving rod of the core bar 24, bevel gear 25 and a bearing 26. The driving rod of the core bar 24 is in turn to cross through the stepped through hole 8 of the column 4 under the middle section of the shunt bracket 9 and the through hole cover 9. The driving rod of the core bar 24 is movably supported and fixed by the bearing 26 which is located in the stepped through hole so that the upper end of the driving rod is located in the blind end cavity of the middle section of the shunt bracket 3 and the lower end is located outside the nether column 4 to connect with the mandrel drive sprocket 27. There are two bevel gears 25. One is installed on supporting active fixed segment of the mandrel 21 in the middle cavity of the shunt bracket 3. The other is geared with the mandrel and installed on top end of one end of driving rod of the core bar 24, located in the middle cavity of the shunt bracket 3. See FIG. 2.

[0055] The mandrel driving sprocket is connected with the transmission sprocket, the coupling and a motor. See FIG. 2.

[0056] The polymer used in this example is random copolymer polypropylene (PPR), trade name of which is RP200. The manufacturer is South Korea's Samsung Chemical. The relevant parameters of the extrusion rheometer are listed: R.sub.o=0.003 m, R.sub.i=0.002 m, r=R.sub.o=0.003 m, L=0.074 m; The setting conditions and tested are listed: temperature 230° C.; pressure value ΔP=1.05 MPa; die speed Ω1=10 rpm=1.04 rad/s; mandrel speed Ω2=0; Q=1.66*10.sup.−8 m.sup.3/s, calculated by the following formulas:

[0057] Axial Shearing Stress:

[00006]${\sigma }_{\mathrm{rz}}=\frac{\Delta .Math..Math.{\mathrm{PR}}_0^2}{4.Math.L}.Math.\left(-\frac{2.Math.r}{R_0^2}+-\frac{2.Math.r}{R_0^2}+\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}.Math.\frac{1}{r}\right)=6703.Math..Math.\mathrm{Pa}$

[0058] Axial Shearing Rate:

[00007]${\gamma }_{\mathrm{rz}}=\frac{2.Math.Q}{\Pi .Math..Math.R^2\left[1-{\left(\frac{R_i}{R_0}\right)}^4-\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}\right]}.Math.\left(-\frac{2.Math.r}{R_0^2}+\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}.Math.\frac{1}{r}\right)=5.97.Math.s^{-1}$

[0059] Hoop Shearing Stress:

[00008]${\sigma }_{r.Math..Math.\delta }=\frac{M_1}{2.Math.\Pi .Math..Math.r^2.Math.L}=6702.Math.\mathrm{Pa}$

[0060] Hoop Shearing Rate:

[00009]${\gamma }_{r.Math..Math.\delta }=\frac{{\Omega }_1\left(\frac{1}{r^2}-\frac{1}{R_0}\right)}{\frac{1}{R_i^2}-\frac{1}{R_0}}=2.72.Math.s^{-1}$

[0061] Combine Shearing Rate:

σ=√{square root over (σ.sub.rz.sup.2+σ.sub.rδ.sup.2)}=36484.8 Pa

[0062] Melt Viscosity:

[00010]$\eta =\frac{\sigma }{\gamma }=5555.4.Math.\mathrm{Pa}.Math.s$

[0063] The outer diameter of the PPR microtubes, prepared under only pressure flow; is about 3 mm and the wall thickness is approximately 0.5 mm. The hoop torsional strength of is 16 MPa and the torsional modulus is 383.5 MPa.

Example 3

[0064] This example is a rheological measurement method capable of simultaneously measuring the pressure and shearing rheology of a polymer.

[0065] The polymer used in this example is random copolymer polypropylene (PPR), trade name of which is RP200. The manufacturer is South Korea's Samsung Chemical. The relevant parameters of the extrusion rheometer are listed: R.sub.o=0.003 m, R.sub.i=0.002 m, r=R.sub.o=0.003 m, L=0.074 m; The setting conditions and tested are listed: temperature 230° C.; pressure value ΔP=3.78 MPa. Die and mandrel rotate in the same direction, mandrel rotating speed Ω.sub.1=40 rpm=4.18 rad/s, the mandrel torque is M.sub.1=0.14N.Math.M; the die rotating speed Ω.sub.2=40 rpm=4.18 rad/s, the die torque M.sub.2=0.12N.Math.M; Q=2. 18*10.sup.−8 m.sup.3/s. These were calculated by the following formula:

[0066] Axial Shearing Stress:

[00011]${\sigma }_{\mathrm{rz}}=\frac{\Delta .Math..Math.{\mathrm{PR}}_0^2}{4.Math.L}.Math.\left(-\frac{2.Math.r}{R_0^2}+-\frac{2.Math.r}{R_0^2}+\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}.Math.\frac{1}{r}\right)=2.77\times {10}^4.Math.\mathrm{Pa}$

[0067] Axial Shearing Rate:

[00012]${\gamma }_{\gamma .Math..Math.z}=\frac{2.Math.Q}{\Pi .Math..Math.R^2\left[1-{\left(\frac{R_i}{R_0}\right)}^4-\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}\right]}.Math.\left(-\frac{2.Math.r}{R_0^2}+\frac{{\left[1-{\left(\frac{R_i}{R_0}\right)}^2\right]}^2}{\ln .Math.\frac{R_0}{R_i}}.Math.\frac{1}{r}\right)=3.29.Math.s^{-1}$

[0068] Hoop Shearing Stress:

[00013]${\sigma }_{r.Math..Math.\theta }=\frac{M_1}{2.Math.\Pi .Math..Math.R_i^2.Math.L}+\frac{M_2}{2.Math.\Pi .Math..Math.R_0^2.Math.L}=3.31\times {10}^4.Math.\mathrm{Pa}$

[0069] Hoop Shearing Rate:

[00014]${\gamma }_{r.Math..Math.\theta }=\frac{{\Omega }_1\left(\frac{1}{r^2}-\frac{1}{R_0}\right)}{\frac{1}{R_i^2}-\frac{1}{R_0}}+\frac{{\Omega }_2\left(\frac{1}{r}+\frac{1}{R_i^2}\right)}{\frac{1}{R_i^2}-\frac{1}{R_0}}=3.14.Math.s^{-1}$

[0070] Combined Shearing Stress:

σ=.sup.2√{square root over (σ.sub.rz.sup.2+σ.sub.rθ.sup.2)}=4.32×10.sup.4 Pa

[0071] Combined Shearing Rate:

γ=.sup.2√{square root over (γ.sub.rz.sup.2+γrθ.sup.2)}=4.55 s.sup.−1

[0072] Melt Viscosity:

[00015]$\eta =\frac{\sigma }{\gamma }=9.55\times {10}^3.Math.\mathrm{Pa}.Math.s$

[0073] The PPR microtubes prepared under pressure/shear compound flow are characterized by an outer diameter of about 3 mm, a wall thickness of about 0.5 mm, a hoop torsional strength of 18.5 MPa and a torsional modulus of 457.8 MPa.

[0074] The above mentioned example is only an example in this invention and not limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies in the same way, all are included in the scope of patent protection of the present invention.