JPH06270140A - Rotor for continuous kneader - Google Patents

Abstract

PURPOSE:To enable the sufficient kneading of a material and to expand theadaptation range to the material by extending the stagnation of the material by weakening the feed force of the material in a kneading part. CONSTITUTION:A pair of rotors 1 are parallelly provided in a barrel 4 having a material supply port at one end thereof and a discharge port at the other end thereof and having a vent port provided to the intermediate part thereof in a freely rotatable manner and, to each of the rotors 1, a first screw feed part 5, a first kneading part 6, a gate part 7, a second screw feed part 8 and a second kneading part 9 are longitudinally provided and a feed blade 6A and a return blade 6B are provided to the first kneading part 6. In the continuous kneader thus constituted, the length ratio R of the feed and return blades 6A, 6B of the first screw part 6 of the rotor 1 is set to 0.8-1.4 and the feed screw 6A is made short to weaken material feed force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor for a continuous kneader with a vent, which is used for kneading and melting a polymer material such as a synthetic resin.

[0002]

2. Description of the Related Art Generally, a vented biaxial continuous kneading machine used for kneading and melting a polymeric material such as a synthetic resin is known as shown in FIG. This kneading machine has a material supply port 21 at one end, a discharge port 22 at the other end, and a barrel 24 having a vent port 23 in the middle thereof.
A rotor 25 of a book is rotatably fitted in parallel, an opening / closing valve 26 is attached to the discharge port 22, and a gate 27 is provided on the upper side of the vent port 23 to reduce the resin flow passage area to the gate 27. The kneading degree can be adjusted by increasing or decreasing by opening and closing.

Then, in each rotor 25, a first screw feed section 28 for feeding the material from the material supply port 21 side as a first stage, a first kneading section 29 for melting and pulverizing the material, and a position corresponding to the gate 27 are provided. Equipped with a gate unit 30,
Following this, as the second stage, a second screw feed section 31 for degassing (venting) and feeding the material and a second kneading section 32 for re-kneading / discharging the material are connected in the longitudinal direction (for example, (See JP-A-56-31433).

Further, as shown in FIG. 9, a vented biaxial continuous kneading machine having an L / D of 7 or less is also known, which is provided with a one-step kneading rotor 34 which eliminates the second kneading section blade and serves as a discharge section 33. . The rotor 34 has a ratio LF / D of the first stage length LF to the barrel inner diameter D (see FIG. 10) of 3.5 or more, and a ratio LS / D of the second stage length LS to the barrel inner diameter D of 1. It is set to 75 or more, and the phase of the flight 35 of the second screw feed portion 31 is matched (see FIG. 10). The kneader comprises L-LDPE (linear low-density polyethylene),
Suitable for low-temperature kneading and high-production in HDPE (high-density polyethylene) kneading.

The turning point of the first kneading section 29 is used as the rotor 25 which can be used for both the weak kneading (low temperature kneading) required for L-LDPE kneading and the strong kneading (high temperature kneading) required for HDPE kneading. Length after 29A and second kneading section 32
It has been proposed that the sum of the lengths of the two is set to 2.2D to 3.3D.

[0006]

When a material such as HDPE or PP (polypropylene) is kneaded in a twin-screw continuous kneader having an L / D of 7 or less, elimination of fish eyes,
When performing strong kneading that requires high dispersibility, the kneading machine equipped with the one-step kneading rotor 34 causes insufficient kneading. However, there is a problem that the operation range of the gate 27 (application range to various materials) is narrow.

The present invention has been made in view of the above situation, and an object thereof is to weaken the feeding force of the material in the kneading section to prolong the residence time of the material and increase the strength of the material. (EN) It is possible to provide a rotor for a continuous kneading machine that can surely perform kneading and widen the range of application to materials.

[0008]

In order to achieve the above object, the present invention takes the following technical means. That is, according to the present invention, two pairs of rotors are rotatably fitted side by side in a barrel having a material supply port at one end and a discharge port at the other end and a vent port at an intermediate portion. In a continuous kneader in which a screw feed section, a kneading section, and a gate section are continuously provided in each rotor in the longitudinal direction, and a kneading section is provided with a feeding blade and a returning blade, the feeding blade of the kneading section of each rotor is The ratio R of the length of the return blade and the length of the returning blade is 0.8 to 1.4.

Further, according to the present invention, the screw feed section and the kneading section of the rotor are arranged before and after the gate section, and the length L1 from the turning point of the first kneading section to the end of the gate section and the second kneading section. The sum of the lengths L2 is 2.2 to 3.3 times the barrel inner diameter D.

[0010]

According to the present invention, the feed force of the material is weakened by setting the length ratio R of the feed blade and the return blade of the kneading section for kneading the material to 0.8 to 1.4. Therefore, the material residence time in the kneading section becomes long, the polymer is sufficiently dispersed by the strong kneading, and the fish eyes can be erased. Therefore, the operation range of the gate opening can be widened, and as a result, various materials can be used. You can expand the range of application of training. Then, the gate opening can be increased to set the temperature of the discharged material to the upper limit (about 220 ° C.) or less, prevent thermal deterioration, and perform good kneading well.

According to the present invention, the kneading section is provided in two stages, and the sum of the length L1 from the turning point of the first kneading section to the end of the gate and the length L2 of the second kneading section is calculated as the barrel. By setting the inner diameter D to be 2.2 to 3.3 times, the material can be effectively plasticized, dispersed and kneaded, and weak kneading and strong kneading can be realized by the same kneading machine.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention, where 1 is 2
A pair of kneader rotors, each of which has the same shape,
A pair of left and right chambers 3 are fitted in parallel to each other through a communication portion 2 and are rotatably mounted in the chambers 3 of a barrel 4 formed in such a manner as to communicate with each other over substantially the entire length so as to be rotatable in opposite directions about their axes. ing. Although not shown in the drawings, the barrel 4 has a material supply port at one end and an intermediate portion (second stage) as shown in FIG.
A vent port for degassing and a molten material discharge port at the other end are provided, and a gate (the same as the gate 27 in FIG. 8) for adjusting the kneading degree is provided on the upper side of the vent port so that the opening degree can be freely adjusted. There is.

Each of the rotors 1 has a two-stage structure for two-stage kneading, and the first stage has a screw-like groove for feeding the material supplied from the material supply port on one end side to the front side (lower side). A first kneading comprising a first screw feed section 5 having the following, and two screw feed blades 6A and two returning blades 6B each having forward and reverse lead angles with a large lead angle for plasticizing and kneading the material. A section 6 and a gate section 7 having a circular cross section for controlling the melting area and preventing a short pass to adjust the degree of kneading are formed.

Further, in the second stage of each rotor 1, a second screw feed section 8 having a thread groove is provided subsequent to the gate section 7, and subsequently a kneading blade 9A and a discharge blade 9B.
And a second kneading section 9 having a
Corresponds to the gate of the barrel 4, and the second screw feed portion 8 corresponds to the vent port. The ratio R between the length of the upper feed blade 6A and the length of the lower return blade 6B from the turning point O of the first kneading section 6 is designed to be 0.8 to 1.4. The blade length ratio R is defined by the material upper limit temperature (Tmax) (maximum temperature for avoiding deterioration of the material) and the material lower limit temperature (Tm) with respect to the shape of the rotor 1, particularly the kneading performance.
in) (minimum temperature at which the material is plasticized and homogeneously kneaded)
And the gate opening (%) (operating range that can be controlled between the upper limit temperature and the lower limit temperature), the results were obtained from various experiments and are clear from FIG.

That is, as shown in FIG. 3, the gate opening is 0.
%, The upper limit temperature (Tmax) is when the blade length ratio R is 1.4, and the lower limit temperature (Tmin) at the control limit gate opening (70%) of the lower limit temperature (Tmin) is
The blade length ratio R is 0.8. From this, by setting the blade length ratio R in the range of 0.8 to 1.4, the operation range of the gate opening is 10 to 70% at the maximum and 0 to 17% at the minimum.
And can be greatly expanded.

If the blade length ratio R is less than 0.8, the lower limit temperature cannot be controlled and the blade length ratio R is 1.4.
When it exceeds, the gate opening degree becomes 0%, that is, the completely closed state due to the relationship of the upper limit temperature (Tmax), and the training cannot be further strengthened. Therefore, it is optimal to set the blade length ratio R in the range of 0.8 to 1.4. The length L from the turning point O of the first kneading section 6 of the rotor 1 to the front end of the gate section 7 is L.
1 and the sum L1 + L2 of the length L2 of the second kneading section 9 are 2.2 to 3. of the inner diameter D of the barrel 4 (inner diameter of the chamber 3).
It is designed to triple. This is based on various experimental results that the kneading portion length L1 in front of the turning point O of the first kneading portion 6 and the length L2 of the second kneading portion 9 have a great influence on the kneading performance. It has been proposed (see Japanese Patent Application No. 3-163112).

That is, as the material (resin) is plasticized and contributes to the dispersion and kneading and consequently affects the material temperature, the kneading section length (L1 + L2) after the turning point O is lengthened, the stronger the kneading becomes. However, when the maximum length L1 + L2 of the kneading portion is 3.3 times the barrel inner diameter D or less, the kneading can be performed to the extent that the heat deterioration can be prevented. . On the other hand, by setting the minimum length of the kneading part (L2 + L2) to be 2.2 times or more the barrel inner diameter D, the number of fish eyes generated is 3 or less,
The material temperature can be raised to loosen and disperse the polymer entanglement, and sufficient kneading becomes possible.

Next, the operation of the embodiment of the present invention will be described. When kneading a material to be kneaded (for example, a resin), the material that is continuously and quantitatively supplied from the supply port of the barrel 4 by a supply device (not shown) is the first screw feed section 5 of the rotor 1 that is continuously rotating. To axially forward,
Sequentially sent at a constant speed. The material sent to the first kneading section 6 is advanced by the feed blade 6A and is sent backward by the return blade 6B to collide with each other, and undergoes shearing, stirring, dispersing, etc. to plasticize and melt. At this time, since the material feeding force becomes weak, the material retention time in the kneading section 6 becomes long,
Sufficient kneading (strong kneading) is performed.

The material plasticized, melted and kneaded in the first kneading section 6 passes through the gate section 7 while the kneading degree is controlled by the gate section 7 and is sent to the second screw feed section 8 to be vented. Is degassed from the mixture, the volatile components contained in the material being kneaded are removed and sent to the second kneading section 9, and the temperature of the material is raised by re-kneading (220 ° C. or less) to loosen the entanglement of the polymer. Are dispersed, the generation of fish eyes is suppressed, and strong kneading is possible.

Since the operating range of the gate opening in the gate section 7 is wide, the pressure in the first kneading section of the material is properly controlled, and the temperature rise due to heat generation due to shearing is also controlled, so that the quality is deteriorated. In addition to avoiding a sharp rise in temperature, uneven kneading due to a short pass of the material is prevented, and insufficient kneading is eliminated. Rotor 1 of the above embodiment
The blade length ratio R of the first kneading section 6 is 1, the kneading section length (L1 + L2) is 2.585D, the blade length ratio R of the conventional one-stage kneading rotor 34 is 1.6, and the kneading section 29 is The length after the turning point 29A is 0.95D, the blade length ratio R of the conventional two-stage kneading rotor 25 is 1.6, and the length after the kneading portion turning point 29A is 2.36D. Perform a kneading test of (HDPE, M1 = 0.08),
The results shown in FIGS. 4 to 7 could be obtained. It should be noted that M1 represents the fluidity of the material by a melt index. Further, the subscript (for example, 5%) in the figure indicates the opening degree of the gate.

FIG. 4 shows the relationship between the rotor shape and the discharge port resin temperature and production amount. In the rotor of the present invention, the temperature rises by about 22 ° C. under the same conditions as compared with the conventional two-stage kneading rotor 25. , Has become a strong training. On the other hand, the conventional rotor 2
No remarkable difference is observed in the resin temperatures at the outlets of both Nos. 5 and 34.
It can be said that this is because the effect of the blade length ratio R of the kneading part has a great influence.

FIG. 5 shows the relationship between the rotor shape and the gate operating range when the material is powder, and it is clear that the rotor 1 of the present invention has a wider gate operating range than the conventional two-stage kneading rotor 25. Is. FIG. 6 shows the relationship between the rotor shape and the gate operation range when the material is pellets. In the rotor 1 of the present invention, the gate operation range (gate opening degree) is 5 to 5 as compared with the conventional rotors 25 and 34. It is as wide as 50%. The gate opening degree of the conventional one-stage kneading rotor 34 is 0 to 10%, and if it is opened more than this, the resin temperature becomes low.

FIG. 7 shows the relationship between the gate opening and the specific energy in the rotor of the present invention, and shows that the control range of the specific energy is wide due to the wide operating range of the gate at both low speed and high speed. The present invention is not limited to the above-mentioned embodiment, and can be applied to, for example, a single-stage kneading rotor.

[0024]

As described above, according to the present invention, a pair of two rotors are arranged in parallel in a barrel having a material supply port at one end and a discharge port at the other end and a vent port at an intermediate portion. And rotatably fitted therein, each rotor is provided with a screw feed section, a kneading section, and a gate section continuously in the longitudinal direction, and the kneading section is provided with a feed blade and a return blade. Since the ratio R of the lengths of the feed blade and the return blade of the kneading part of the rotor is set to 0.8 to 1.4, the feeding force of the material in the kneading part is weakened to reduce the material. In addition to being able to solve the shortage of kneading and to realize strong kneading, the operation (opening) range of the gate can be widened, so that the range of application to various materials can be expanded.

Further, according to the present invention, the screw feed section and the kneading section of the rotor are arranged before and after the gate section, and the length L1 from the turning point of the first kneading section to the end of the gate section and the second kneading section. Since the sum of the lengths L2 is set to be 2.2 to 3.3 times the barrel inner diameter D, the quality of the kneaded material is weakly kneaded to avoid thermal deterioration, and thus has high dispersibility. The same kneading machine can be used until the material is strongly kneaded.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 3 is a graph showing the relationship between the blade length ratio of the kneading section and the gate opening.

FIG. 4 is a graph showing the relationship between rotor shape and discharge port resin temperature.

FIG. 5 is a graph showing the relationship between the rotor shape and the gate operation range when the material is powder.

FIG. 6 is a graph showing the relationship between the rotor shape and the gate operating range when the material is pellets.

FIG. 7 is a graph showing the relationship between gate opening and specific energy in the example of the present invention.

FIG. 8 is a partially cutaway front view showing a conventional biaxial continuous kneader with a vent.

FIG. 9 is a plan view showing another conventional example.

10 is an enlarged cross-sectional view taken along the line BB of FIG.

[Explanation of symbols]

 1 Rotor 4 Barrel 5 1st screw feed part 6 1st kneading part 6A Feeding blade 6B Returning blade 7 Gate part 8 2nd screw feed part 9 2nd kneading part D Barrel inner diameter L Rotor length L1 1st kneading part From the turning point Length to front end of gate L2 Length of second kneading section O Turning point of first kneading section R Blade length ratio of first kneading section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Kimura Inventor Hirofumi Kimura 2-3-1, Niihama, Arai-cho, Takasago-shi, Hyogo Inside the Takasago Plant, Kobe Steel, Ltd. (72) Shoji Yasuda 2-chome, Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture 3rd-1 Kobe Steel Co., Ltd. Takasago Works (72) Inventor Susumu Takaraya 2-3-1 Niihama, Arai-cho, Takasago-shi, Hyogo Kobe Steel Works Takasago Works

Claims (2)

[Claims] 1. A barrel having a material supply port at one end and a discharge port at the other end and a vent port at an intermediate portion,
Two pairs of rotors are rotatably fitted side by side, and each rotor is provided with a screw feed section, a kneading section, and a gate section continuously in the longitudinal direction, and the kneading section is provided with a feed blade and a return blade. A rotor for a continuous kneading machine, characterized in that in the continuous kneading machine, a ratio R of the lengths of the feeding blades and the returning blades of the kneading portion of each rotor is set to 0.8 to 1.4. 2. A screw feed portion and a kneading portion of the rotor are arranged before and after the gate portion, and a length L1 from a turning point of the first kneading portion to an end of the gate and a length L2 of the second kneading portion.
2. The rotor for a continuous kneading machine according to claim 1, wherein the sum of the above is 2.2 to 3.3 times the inner diameter D of the barrel.