JPH0234307A - Manufacture of polymer containing powder additive - Google Patents

Abstract

PURPOSE:To uniformly disperse added powder by setting the thickness of a kneading disc for forming a kneading zone to 0.2 times or more as large as the diameter of a screw in a first half, setting it to 0.1 times or less as large as that in a second half, and further specifying the arraying angle of the disc. CONSTITUTION:A kneading zone length is set to a screw length L, which is ranged from 0.2XL to 0.4XL. The thickness of a kneading disc is set to 0.2XD in a first half and to 0.1XD in a second half, where the D is the diameter of the screw. Powder to be quantitatively supplied from a powder constant feeder 1 and chip to be quantitatively supplied from a chip constant feeder 2 are so kneaded in a kneading zone 3, KD section that the total length is L, and polymer is discharger. The deviation angle of the discs is set to 0-20 deg. thereby to enhance kneading effect and to reduce the deterioration the polymer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be used for applications such as LII fibers, films, and resins in a state in which powder additives are uniformly dispersed and a decrease in intrinsic viscosity is suppressed. The present invention relates to a method for producing a polymer containing a powder additive using a screw-type twin-screw kneading extruder.

[Prior art] Thermoplastic polymers such as polyethylene terephthalate,
Polyesters such as polybutylene terephthalate and polyamides such as nylon 66 and nylon 6 are widely used in large quantities for films, resins, fibers, etc., but they can be used to add performance or improve properties depending on the application. It is common to use additives such as lubricants, pigments, flame retardants, antistatic agents, fillers, etc. in combination in order to It was added in solid or solution form.

However, in recent years, in order to create a wide variety of value-added polymers from one type of base polymer, adding it during the polymerization reaction results in a large amount of loss when switching brands, so switching losses have been reduced. JP-A No. 58-2L2908 is used as a means to adjust the concentration of additives, or to freely change the concentration of additives, or to create a master polymer containing additives at a high concentration and then dilute it and mold it. A method has been proposed in which a powder additive is kneaded into a molten polymer after polymerization using a screw-type twin-screw kneading extruder as disclosed in the publication.

However, the higher the concentration of powder additives, especially the additives, the more difficult it becomes to uniformly disperse and mix them into the polymer, and if the dispersion and mixing are insufficient, productivity during molding or product quality may be affected. This will have an impact.

Therefore, in order to sufficiently and uniformly disperse the additive into the polymer, it is necessary to apply strong shear stress to the polymer and the additive for a long period of time.

However, on the other hand, when additives are directly introduced into a high-temperature twin-screw extruder and subjected to strong shear stress, agglomeration occurs due to heat shock, and conversely, a satisfactory dispersion and mixing state cannot be obtained, and strong shear Due to prolonged exposure to shear heat generation that generates stress, the intrinsic viscosity of the extruded additive-containing polymer decreases significantly, leading to problems such as poor moldability or insufficient product quality. .

Conversely, shear stress, which suppresses the decrease in intrinsic viscosity,
Polymers and additives may If sufficient shear stress is not applied, the additives in the polymer may aggregate, making it impossible to obtain a satisfactory dispersion/mixing state.

[Object of the invention] The present invention solves the above-mentioned problems, uses a screw-type twin-screw kneading extruder to uniformly disperse powder additives, and suppresses the decrease in intrinsic viscosity when roughness is required. The object of the present invention is to provide a method for producing a powder additive-containing polymer.

In order to achieve this objective, the present inventors have made numerous studies and have found that the arrangement and thickness of the kneading disks that constitute the kneading zone of the twin-screw kneading extruder screw are important factors. As a result of intensive repeated experiments and studies on these matters, the present invention was arrived at.

[Structure of the Invention] That is, the present invention involves kneading a thermoplastic polymer and a powder additive using a screw-type twin-screw kneading extruder provided with a kneading zone consisting of at least two kneading disks that rotate relative to each other. When dispersing powder additives to produce powder additive-containing polymers, the thickness of one disk is 0.2x.
The first half placed above D (screw diameter), then 0.1
Passing through a kneading zone having a total length of 0.2L (screw length) or more and 0.4×L or less with a rear half arranged below ×D, and after initial kneading in the front half of the zone,
Disk shift angle (phase angle) formed in the rear half is 0 to 2
This is a method for producing a powder additive-containing polymer, characterized in that the mixture is kneaded by passing through a group of forward kneading disks at 0 degrees and a group of backward kneading disks at -30 to -50 degrees.

In the present invention, thermoplastic polymers produced by existing polymerization methods are supplied to a twin-screw extruder in pellet form or in a molten state from a polymerization tank, and powder additives (including fine particles) are supplied separately. By kneading with a screw-type twin-screw kneading extruder (hereinafter referred to as a twin-screw extruder), the powder additives are uniformly dispersed, but the dispersion state is generally good and the intrinsic viscosity is suppressed from significantly decreasing. can do.

Here, in the kneading zone, the group of kneading disks located first at the entrance (input port) of the powder additive forms the first half, and the remaining part forms the second half; The total length, that is, the kneading zone length, is 0.2Xl or more and 0.2Xl or more. It must be less than I×L, and this length is 0.4
If it is larger than Xl, the intrinsic viscosity may decrease significantly due to the influence of shear heat generation and the like. Also, below 0.2×L,
This is undesirable because the dispersion of the powder additive deteriorates and the number of aggregated particles increases rapidly. Furthermore, even if the kneading zone length is within the above range, the thickness of one kneading disk is 0.2 XD for both the first and second half (D is slightly smaller than the inner diameter of the barrel placed in the kneading zone). If it is more than that, there will be less opportunity for kneading and the state of dispersion will deteriorate, which is not preferable. - both the first half and the second half are 0
．． If it is less than 1D, the shear heat generation at the initial stage of kneading will increase,
Dispersion deteriorates due to agglomeration of powder additives due to heat shock. For the same reason, even if the first half is 0.1xD or less and the second half is 0.2xD or more, the dispersion deteriorates.

Next, even if the kneading zone length is set to 0.2X1 or more and 0.4XL or less, and the thickness of one kneading disk is set to 062XD or more in the first half and 0.1XD in the second half, the kneading disk If the disc group for forward kneading has a shift angle of 0° or more and +20' or less, and the disc group for reverse kneading has a shift angle of 130' or less and is larger than 150', the dispersion state will deteriorate.

For example, if the displacement angle of the kneading disk in the first half is larger than +20", the screw rotation torque consumed in the first half of the kneading zone will only be involved in feeding the thermoplastic polymer, and the dispersion state will tend to deteriorate without increasing the opportunity for dispersion. .

If the temperature is less than 0°, the residence time of the thermoplastic polymer in the twin-screw router will increase due to the placement of the reverse kneading disk, and the thermoplastic polymer will be exposed to strong shear stress for a long period of time, resulting in deterioration and the intrinsic viscosity will significantly decrease. descend.

If the shift angle of the kneading disk in the latter half of the rough kneading zone is made larger than 130', the thermoplastic polymer sent from the first half will pass through, and the next step will be carried out before sufficient shear stress is applied to the thermoplastic polymer. The liquid will be sent to the stage, and the state of dispersion will deteriorate. In addition, if it is less than -50", the polymer residence time will increase and the intrinsic viscosity will decrease due to deterioration. In some cases, the flow balance will be disrupted and the polymer will flow out into the vacuum suction port of the twin-screw router, causing contamination of degraded substances and vacuum There are concerns about a decline in the level of

The powder additives used in the present invention include, for example, titanium oxide, carbon black, silica, calcium carbonate, alumina, etc.; Stabilizers added in the state.

Flame retardants, fluorescent agents, dyes, etc. can also be used.

Hereinafter, the present invention will be explained based on the drawings. Fig. 1 is a schematic explanatory diagram of a two-axis ruler suitable for carrying out the present invention;
This figure and FIG. 3 are a sectional view taken along line AA' and a view taken along line BB' in FIG. 1, respectively.

In the figure, the powder quantitatively supplied from the powder quantitative feeder 1 and the chips quantitatively supplied from the chip quantitative feeder 2 are mixed into a kneading zone (KD section) 3 and a KD section 3 whose total length is L. The powder additive is introduced from the inlet 6 of a two-screw router 5 having a screw with a diameter D (Fig. 2) consisting of a full-flight section 4 other than the above, and the screw is rotated at a rotation speed N to discharge the powder additive from the discharge lower. Discharge the polymer.

Note that 8 and 9 are vents for degassing. In this case, the supply mQ is defined as the total amount of powder and chips supplied from feeders 1 and 2.

Further, the temperature of the barrel 10 is controlled to be constant by a heater and cooling water. As shown in Fig. 2, the KD section 3 consists of a pair of opposing rice ball-shaped disks that are axially shifted at a predetermined angle and rotate in contact with each other. An elliptical disk as shown in FIG. 4 described in the publication or other known kneading disks may be used. Furthermore, although the full-flight section 4 that rotates in the same direction as shown in FIG. 3 is normally used, it is also possible to use one that rotates in mutually different directions as shown in FIG.

Note that the shift angle is defined as a positive direction when the downstream disk is shifted in the opposite direction to the rotational direction with respect to the upstream kneading disk. In this case, the flights are arranged so as to extrude the polymer toward the discharge die.

In the case of the rotation direction shown in FIG. 8, the deviation angle α is in the positive direction.

Powder quantitatively supplied from the powder window layer feeder 1 and chips quantitatively supplied from the chip quantitative feeder 2 are simultaneously inputted from the input port 6. 11 in the first half of kneading zone 3
The zone is a zone where the thickness of one kneading disk is 0.2X[) or more, and the chips and powder are first melted and initially kneaded here. After the initial kneading, the powder-containing polymer is deaerated from the vent 8 and guided to the second half of the kneading zone 3 while deterioration is suppressed. In the upper two parts of the second half of the kneading zone, the thickness of one kneading disk is 0.1×D or less, and the shift angle (phase angle) of each kneading disk is 0°.
Consists of a group of forward kneading disks with a displacement angle of 130' or less and a displacement angle of 150° or more, and a group of reverse kneading disks with a shift angle of 130' or less and a displacement angle of 150° or more, resulting in an efficient kneading effect and a good dispersion state. can be obtained, and there is little deterioration of the polymer.

Furthermore, the powder-containing polymer is degassed in a vent 9 to prevent deterioration and is discharged from the discharge lower.

The shift angle α is 2, which passes through the apex of the kneading disk 3 drawn parallel to the central axis (line) 1 of the screw shaft, as shown in Fig. 8.
It is the angle between the two parallel lines 11 and 12 with respect to the central axis.

In addition, in the method of the present invention, instead of supplying chips quantitatively as shown in FIG. 6, the polymer is supplied in a molten state from the existing final polymerization tank for thermoplastic synthetic resin to the twin-screw loop through the polymer pipe 11. At the same time, the powder can also be introduced through the input port 12. Furthermore, as shown in FIG. 7, the input port 18.
It is also possible to supply chips to the input port 19 and powder to the input port 20, and it goes without saying that the supply of chips and powder is not limited to these, and can be performed in various combinations using one or more input ports.

As described above, when producing polymers containing powder additives using various twin-screw routers according to the present invention, the difference in [η] between the supplied polymer and the product is small, and the powder additives in the polymer are small. It becomes possible to obtain a polymer with excellent dispersibility.

Furthermore, polymers containing various additives produced by the method of the present invention can be used in a wide range of applications such as fiber applications, films, and general molded products.

[Example] Example 1 Using a two-wheeled Ruder as shown in the figure, the cylinder temperature of the two-shaft Lugu was 270°C, 9 rotations 30 Or, l), m
40wt of titanium oxide (Ti■) with an average particle size of 0.3μ
% polyethylene terephthalate (PET) was produced at 100 Kg/Hr.

In this case, the diameter of the twin Ruder screw is 65 mm.
The test was conducted using a screw length L of 2000 mm and varying the zone length of the kneading disk used in the kneading zone.

The obtained master chip has an overall TiQ2 concentration of 1wt.
The mixture was blended with PE chips at a certain rate, remelted and discharged into a film, and then centrifuged to measure the coarse particles (agglomerated particles) of 50 microns or more per 100 cm+2 of the film obtained under an optical microscope.

Furthermore, after the separation of TiQ2, the intrinsic viscosity [η] was also measured, and these results are shown in Table 1 along with the measurement of coarse particles.

The intrinsic viscosity used in the present invention was determined from the viscosity measured in an orthochlorophenol solvent at 25°C.

Further, in order to measure these surface properties, films obtained by diluting the TiQ2 concentration to 10 wt% in the same manner as described above were visually inspected, and those showing worsening of white discoloration and a large amount of light scattering were judged as defective.

This quality is determined by surface roughness Ra (center line average roughness, JI
This corresponds to approximately 0.07 when measured by SBO601), and those exhibiting a value larger than this are unlikely to be good products.

Furthermore, if the [η] of the supplied PET is 0.65 and the [η] of the obtained master chip is 0.49 or less, the strength of the film obtained by diluting the TiQ2 concentration to 10 wt% will be low and will be a good product. It was classified as defective because it was small.

Example 2 Table 2 shows examples in which evaluations were conducted under substantially the same conditions as in Example 1, with various thicknesses of the kneading disks in the kneading zone.

From this table, it can be seen that it is not good if the disk thickness is out of a specific range.

Example 3 Table 3 shows an example in which tests were conducted under substantially the same conditions as in Example 1, with the kneading zone length and disk thickness specified, and the disk deviation angle varied. From this table, it can be seen that it is not good if the disc deviation angle is outside a specific range.

"Effects of the Invention" As explained above, according to the present invention, in the conventional polymerization process, etc.
Compared to the method of dispersing in an organic solvent and adding it in the form of a slurry, it is possible to produce a wide variety of products in small quantities.Although it contains a high concentration of pigment, it is possible to produce master chips with good dispersibility while suppressing a decrease in the intrinsic viscosity. Production is also possible, resulting in significant cost reductions.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a two-axis ruler suitable for carrying out the present invention, FIGS. 2 and 3 are a sectional view taken along the line A-A" and a view taken along the line B-8' in FIG. 1, respectively; 4 and 5 are explanatory diagrams each showing other examples, and FIGS. 6 to 8 are explanatory diagrams each showing other two-axis rulers applied to the present invention. 1... Powder quantitative feeder , 2... Chip quantitative feeder, 3... Kneading zone, 5... 2-axis ruler-16.
...Input port, 7...Discharge port.

Claims (1)

[Claims] A thermoplastic polymer and a powder additive are kneaded by a screw-type twin-screw kneading extruder equipped with a kneading zone consisting of at least two kneading disks that rotate opposite each other, and the powder additive is dispersed to form a powder. When producing an additive-containing polymer, the total length of one disk is 0.2L, which has a first half arranged at a thickness of 0.2 x D (screw diameter) or more, and a second half arranged at a thickness of 0.1 x D or less. (screw length) or more is 0
．． Through a kneading zone formed with a length of 4 x L or less, after initial kneading in the first half of the zone, a group of progressive kneading disks with a disk shift angle (phase angle) of 0 to 20 degrees formed in the latter half. A method for producing a powder additive-containing polymer, which comprises kneading by passing through a group of reverse kneading disks at -30 to -50 degrees.