JP5582863B2 - Kneading method of kneading material - Google Patents

Description

  The present invention relates to a kneading method in which a kneaded material is kneaded by, for example, a kneader.

  In general, as a kneader for kneading resin materials, for example, there is one shown in Patent Document 1. In the kneading machine of Patent Document 1, a pair of left and right kneading rotors that are parallel to each other are rotatably inserted into a chamber having a material supply port and a material discharge port. A feed portion for conveying the material to be kneaded downstream is formed on the outer peripheral surface, and a first kneading portion and a second kneading portion for kneading the material to be kneaded by applying a high shear force are provided on the kneading rotor. It is provided apart in the axial direction.

JP-A-11-58369

  By the way, in recent years, the types of materials to be kneaded (kneaded resin materials) have increased, and the kneaded materials are often finally formed into various shapes such as extremely thin films. In particular, when manufacturing ultra-thin films, the presence of component bias and bubble entrainment (fish eyes) in the kneaded material is a situation that must be avoided as much as possible. Therefore, higher kneading ability than before is required. The kneader shown in Patent Document 1 can produce a kneaded material that substantially satisfies such performance and can suppress fish eyes to some extent.

However, even the kneading machine disclosed in Patent Document 1 may not be sufficient for the recent demand for uniform kneading, and kneading of the kneaded material that can reliably suppress fish eyes. A method is desired.
The present invention has been made in view of the above problems, and a kneading method for a kneading material capable of suppressing fish eyes such as a film by appropriately kneading a kneading material as a base material such as a film. The purpose is to provide.

In order to achieve the above object, the present invention has taken the following measures.
That is, the technical means for solving the problems in the present invention is a distribution kneading that distributes oil around the matrix resin of the kneaded material when the kneaded material containing the powdery matrix resin and oil is kneaded. In this point, after the distributed kneading process, a dispersion kneading process is performed in which kneading is performed while applying shear to the kneaded material.

The distribution kneading process is performed in a gear kneading unit provided in a kneader, and the dispersion kneading process includes a high-order chip part with a narrow chip clearance and a low-order chip part with a wider chip clearance than the high-order chip. It is preferable to carry out in a variable clearance kneading section provided with a flight and provided downstream of the gear kneading section.
It is preferable that the temperature at which the distribution kneading treatment is performed is equal to or higher than the melting point of the base material resin, and the temperature at which the dispersion kneading processing is performed is equal to or lower than the melting point of the base material resin.

The base material resin is preferably high density polyethylene, and the oil is preferably paraffin oil. It is preferable to mix and knead ultra-high molecular weight polyethylene with the matrix resin.
Further, the most preferable mode of the kneading material kneading method according to the present invention is to distribute oil around the kneading material base material resin when kneading the kneading material containing the powdery base material resin and oil. Performing a distribution kneading process, after the distribution kneading process, performing a dispersion kneading process for kneading while adding shear to the kneaded material, and performing the distribution kneading process in a gear kneading section that imparts a dispersibility to the kneaded material, The temperature when performing the distribution kneading process in the gear kneading part is equal to or higher than the melting point of the base resin, and the dispersion kneading process is performed with the high-order chip part having a narrow chip clearance between the inner wall of the barrel and the tip end, A variable clearance kneading part having a flight with a lower tip part having a wider tip clearance than a higher order chip and provided downstream of the gear kneading part There, the temperature at the time of performing the dispersing kneaded in the variable clearance kneading section, characterized by the following melting point of the matrix resin.

  According to the present invention, by appropriately kneading a kneading material that is a base material such as a film, it is possible to reliably suppress the occurrence of component bias and bubble entrainment (fish eye) in the kneading material.

It is the figure which showed the kneading machine for performing the kneading | mixing method of a kneading | mixing material. It is the 1st graph which put together the area of the foreign material per unit volume for every process. It is the 2nd graph which put together the area of the foreign material per unit volume for every processing.

Hereinafter, the kneading method of the kneading material of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a kneader for carrying out the kneading method of the kneading material of the present invention. First, the kneader will be described. The kneading method of the kneaded material is not limited to the kneader shown in FIG.

As shown in FIG. 1, the kneading machine 1 includes a hollow barrel 2 and a kneading screw 4 provided so as to pass through the inside of the barrel 2 along the axial direction. By rotating, the kneading material (kneading resin material) in the barrel 2 is kneaded and sent to the downstream side.
In the following description, the left side of the paper surface of FIG. 1 is the kneader 1 as the upstream side, and the right side of the paper surface is the downstream side. Moreover, let the kneading machine 1 be an axial direction in the left-right direction of the paper surface of FIG. Furthermore, a direction perpendicular to the axial direction is referred to as an axial vertical direction when the kneader 1 is described.

The barrel 2 is formed in a long cylindrical shape along the axial direction, and the inside thereof is a cavity having a cross-sectional glasses shape. A hopper 5 for supplying material into the barrel 2 is provided on the upstream side in the axial direction of the barrel 2, and an electric heater or a heating device (not shown) using heated oil is provided inside the barrel 2. It has been.
A pair of left and right kneading screws 4 are provided inside the cavity of the barrel 2. Each kneading screw 4, 4 includes a spline shaft 6 formed along the axial direction, and a plurality of segments are fixed in a penetrating manner by the spline shaft 6.

As shown in FIG. 1, in the kneading screw 4 of the present embodiment, from the upstream side to the downstream side, the feeding part 10 that is sent to the downstream side while melting the supplied material and the feeding part 10 are sent. A kneading part 11 for kneading the material and an extruding part 12 for feeding the material kneaded in the kneading part 11 downstream are provided.
The feed unit 10 is composed of a plurality of screw segments 13 arranged in the axial direction. The screw segment 13 includes a screw flight (not shown) spirally twisted in the axial direction, and can feed material from the upstream side to the downstream side.

The extrusion unit 12 also has a plurality of screw segments 13 provided with screw flights twisted in a spiral like the feed unit 10 in the axial direction .
Mixing kneading unit 11 is provided with a gear kneading portion 20 located on the upstream side, and a VCMT kneading section 21 located on the downstream side of the kneading section 20 (variable clearance kneading unit).

The gear kneading part 20 is configured by a gear kneading segment having a concavo-convex shape on the outer peripheral surface and having a gear shape in a sectional view. The gear kneading section 20 imparts high distribution to the material to be kneaded by guiding the material between the pair of gear kneading sections 20 and also kneading the material between the inner wall of the barrel 2. be able to.
The VCMT kneading part 21 provided on the downstream side of the gear kneading part 20 is composed of a rotor segment.

  This rotor segment has a high-order tip portion 22 having a narrow tip clearance (inner wall of the barrel 2 and the tip end and a gap), and a low-order tip portion 23 having a tip clearance wider than the high-order tip portion 22 alternately in the axial direction. Have That is, the tip clearance of the high-order tip portion 22 is made smaller than the clearance of the low-order tip portion 23. Since the material is guided to this small tip clearance and kneading is performed while applying a shearing force to the material, High dispersibility can be imparted.

On the other hand, the low tip portion 23, the chip and clearance is greater than the high tip portion 22, for performing the kneading material leading the material to the large tip clearance, it can impart a high dispersion material is kneaded .
Hereinafter, the kneading method of the kneaded material of the present invention will be described in detail.
When the kneaded material is kneaded by the kneading method of the present invention, when the kneaded material (original material) is made into a film, fish eyes can be suppressed. For example, an original material of a separator for a lithium ion battery is manufactured. Suitable for

  In a production method capable of suppressing fish eyes, that is, a kneading method, first, a powdery matrix resin made of at least high-density polyethylene (HDPE) and paraffin that permeates so as to surround the matrix resin. Oil is supplied to the hopper 5. The supplied kneading material is sent to the downstream side by the feeding unit 10, and the distribution kneading process is performed by the gear kneading unit 20.

In the present embodiment, a mixture of high density polyethylene, ultrahigh molecular weight polyethylene, and paraffin oil in a ratio of 6: 9: 35 (mass ratio) is used as the kneading material. Here, you may mix ultrahigh molecular weight polyethylene (UHMWPE) with the kneading | mixing material, ie, high-density polyethylene which is base material resin.
As described above, in the distribution kneading process, the kneading process is performed on the kneaded material containing high-density polyethylene and paraffin oil, so that the paraffin oil swells by being acclimated to the base material resin, etc. Is increasing.

  After performing the distribution kneading process, the dispersion kneading process is carried out to increase the dispersibility by mainly applying shear to the kneaded material which has been sent to the downstream side and has improved the dispersibility by the VCMT kneading unit 21. The VCMT kneading part 21 also has a role of extending the kneaded material by the lower tip part 23 to improve the distribution. Therefore, when looking at the dispersion kneading process from the distribution kneading process, the distribution property of the kneaded material is increased by the distribution kneading process, and then the distribution property and dispersibility are further improved by the dispersion kneading process.

In this way, the kneading material is distributed and kneaded to distribute the oil around the base material resin, and after the kneading material, the kneading material is subjected to a dispersion kneading process in which kneading is performed while shearing. As a result, the dispersibility and dispersibility are improved, and as a result, the material can be uniformly kneaded and the fisheye can be reliably suppressed.
Table 1 summarizes the number of foreign matters when the film is kneaded by the method of the present invention and then formed into a film, and when the film is kneaded by a method different from the present invention and formed into a film. FIG. 2 summarizes the areas of foreign matter per unit volume in Table 1.

  For kneading, a KTX46 kneader 1 manufactured by Kobe Steel was used. The kneading material was kneaded at a feed rate of 75 kg / h and the kneading machine 1 at a screw speed of 200 rpm.

As shown in Table 1 and FIG. 2, after performing the distribution kneading process in the gear kneading part 20 (GN) and further performing the distribution kneading process in the gear kneading part 20 (GN) (comparative example) 1: GN + GN), that is, when the gear distribution kneading process was continuously performed, the area of foreign matters (for example, fish eyes) per unit volume was about 0.012.
Further, after the dispersion kneading process is performed in the VCMT kneading unit 21 (VCMT), and further the dispersion kneading unit is performed in the VCMT kneading unit 21 (VCMT) (Comparative Example 2: VCMT + VCMT), that is, the dispersion kneading unit Was continuously performed, the area of the foreign matter per unit volume was about 0.014.

  On the other hand, as in the present invention, when the dispersion kneading process is performed in the VCMT kneading part 21 (VCMT) after the distribution kneading process is performed in the gear kneading part 20 (GN) (Example 1: GN + VCMT), the area of the foreign matter per unit volume can be reduced to about 0.00089, and can be very small as compared with other comparative examples. Furthermore, in Example 1 (GN + VCMT), the number of foreign matters per unit volume could be reduced very much.

According to the present invention, when kneading a kneaded material containing a powdery base resin and a swelling oil, the dispersion kneading process is performed after the distribution kneading process, thereby reducing the number of foreign matters that suppress fish eyes. Things can be manufactured.
[Second Embodiment]
In the second embodiment, the temperature at which the distribution kneading process is performed and the temperature at which the dispersion kneading process is performed are defined. That is, in the present invention, the temperature at which the distribution kneading process is performed is equal to or higher than the melting point of the base resin. For example, when the base material resin is high-density polyethylene (HDPE), the temperature of the gear kneading part 20 and the temperature at the time of processing (processing temperature) are determined from the melting point (about 130 ° C.) of the high-density polyethylene by a heating device. The temperature is also set to 180 ° C. Thereby, in the distribution kneading process, the high-density polyethylene is easily dissolved, and since the richness by the oil advances, the distribution can be further improved.

  Further, the temperature at which the dispersion kneading process is performed is set to be equal to or lower than the melting point of the base resin. For example, when the base material resin is high-density polyethylene (HDPE), the temperature of the VCMT kneading unit 21 and the temperature during processing (processing temperature) are set higher than the melting point (about 130 ° C.) of the high-density polyethylene by a heating device. The temperature is low 100 ° C. Thereby, in the dispersion kneading process, the high-density polyethylene can be easily sheared, and the dispersion can be further improved.

Table 2 summarizes the number of foreign matters when the film is kneaded by the method of the present invention and then formed into a film, and when the film is kneaded by a method different from the present invention and formed into a film. FIG. 3 summarizes the areas of foreign matter per unit volume in Table 2.
In the kneading, the kneading material was fed at a feed rate of 75 kg / h and the kneading machine 1 was rotated at 300 rpm.

  As shown in Table 2 and FIG. 3, the processing temperature in the distribution kneading process is 180 ° C., which is higher than the melting point of the base resin, and the processing temperature in the dispersion kneading process is 100 ° C., which is lower than the melting point of the base resin. In this case (Example 3: GN + VCMT), the area of the foreign matter per unit volume could be reduced to 0.00356, and a kneaded material that was uniformly kneaded and less likely to generate fisheye than the other comparative examples could be produced.

  On the other hand, in Comparative Example 3, in addition to continuously performing the distribution kneading process, the processing temperatures of the distribution kneading process and the dispersion kneading process are the same, so the area of the foreign matter was the largest. In Comparative Example 4, since the processing temperature when the post-processing (second distribution kneading processing) is performed is lower than the melting point of the base resin, the area of the foreign matter can be reduced to some extent, but the present invention is carried out. Compared to Example 3, it was very large.

Even when Comparative Example 3 and Example 2 in which the processing temperatures of the distribution kneading process and the dispersion kneading process are the same are compared, in Example 2, the dispersion kneading process is performed after the distribution kneading process. Compared with Comparative Example 3, the area of the foreign matter could be reduced.
In addition, as shown in the examples and comparative examples, even when looking at the number of foreign matters per unit volume, the processing temperature in the distribution kneading process is higher than the melting point of the base material resin, and the processing temperature in the dispersion kneading process is The number of Example 3, which was lower than the melting point of the base resin, was the smallest.

According to the present invention, the dispersion kneading process is performed after the distribution kneading process, and the temperature at which the distribution kneading process is performed is equal to or higher than the melting point of the base resin, and the temperature at which the distribution kneading process is performed is By making it below the melting point of the base material resin, it is possible to produce a product with less foreign matter with fish eyes suppressed.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Kneading machine 2 Barrel 4 Kneading screw 5 Hopper 6 Spline shaft 10 Feed part 11 Kneading part 12 Extrusion part 13 Screw segment 20 Gear kneading part 21 VCMT kneading part (variable clearance kneading part)
22 Higher chip part 23 Lower chip part

Claims (3)

When kneading a kneaded material containing a powdery base resin and oil,
Perform a distribution kneading process to distribute oil around the base resin of the kneaded material,
After the distribution kneading process, performing a dispersion kneading process for kneading while adding shear to the kneaded material,
The distribution kneading process is performed in a gear kneading section that imparts distribution to the kneaded material, and the temperature when the distribution kneading process is performed in the gear kneading section is equal to or higher than the melting point of the base resin.
The gear kneading portion has a flight including a high-order tip portion having a narrow tip clearance between the inner wall of the barrel and a tip end of the barrel and a low-order tip portion having a wider tip clearance than the high-order tip. the are performed by the variable clearance kneading section which is provided on the downstream side, the temperature at the time of performing the dispersing kneaded in the variable clearance kneading section, of the kneaded material, characterized by the following melting point of the matrix resin Kneading method. The method for kneading a kneaded material according to claim 1 , wherein the base resin is high-density polyethylene, and the oil is paraffin oil. The method for kneading a kneaded material according to claim 1 or 2, wherein ultrahigh molecular weight polyethylene is mixed with the matrix resin and kneaded.