JP2002210733A - Method for manufacturing colored resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a resin colored composition capable of being (2) industrially adopted (1) with safety without scattering a pigment and having (3)good quality such as dispersibility, transparency and the like, or more particularly to provide a method for manufacturing the resin colored composition having no rough and large particle in a continuous kneader and a small mean particle size of a pigment. SOLUTION: The method for manufacturing the resin colored composition comprises the step of kneading a thermoplastic resin and the pigment, by using a uni-axial screw extruder having temperature regulating zones at two or more positions each containing a pie for distributing a heating medium to a barrel, and a highly dispersing function to manufacture the colored resin composition for dispersing the pigment in the thermoplastic resin. The method further comprises the step of setting a temperature of the heating medium to be distributed to the pipe of the temperature regulating zone nearest to a material filling hole to a temperature lower by 40 deg.C than a softening point temperature of the thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a coloring resin composition useful for a colorant for a resin, an electronic toner, and the like. More specifically, the present invention relates to a method for producing a coloring resin composition by kneading a powder pigment and a thermoplastic resin. Which is excellent in pigment dispersibility, has a maximum of 80 μm or less in coarse particles in which pigment aggregates are solidified in the composition, and can provide a colored resin composition excellent in transparency. About the method.

[0002]

2. Description of the Related Art A method for producing a colored resin composition using a thermoplastic resin and a powdered pigment as raw materials is a method of mixing a pigment and a thermoplastic resin, and using a batch method such as a heating kneader, a heated three rolls, and a heated two rolls. The method can be broadly classified into a method of kneading with a kneader and a method of kneading with a continuous kneader such as a twin screw extruder or a single screw extruder.

[0003] The kneading machine used in the above method is of a batch type, which requires labor for operation and low productivity.
In addition, since it is an open system, there are problems in terms of environment and safety, such as scattering of the powder pigment and injury due to contact with the rotating part.

[0004] On the other hand, the kneader used in the above method has an advantage of high productivity since continuous production is possible. It is said that a twin-screw extruder generally has a higher dispersing function than a single-screw extruder. However, solidified coarse particles of pigment aggregates are likely to remain on the material to be kneaded, and the average particle size of the pigment is hardly reduced compared to a method of kneading with a batch-type kneader over time, so that sufficient transparency is obtained. There is a problem that it is difficult to obtain the properties and coloring power.
As disclosed in JP-A-6-11895 and JP-A-66563, kneading at a temperature lower than the softening point of the resin is said to be effective for obtaining a high pigment dispersion. However, the twin-screw extruder has the following problems.

[0005] The twin-screw extruder is a mechanism in which a material is pushed into a narrow inner space of a barrel and the pigment is dispersed by grinding the material between the inner wall of the barrel and a screw. However, if the barrel temperature is significantly lower than the resin softening point, the viscosity of the material to be kneaded becomes high, resulting in an overload, and the screw cannot be rotated. It is common to keep it near or above.
In the twin-screw extruder, the amount of heat generated by grinding is large, while cooling is not sufficient, so that the kneading temperature rises and the viscosity of the material to be kneaded decreases. It is said that dispersion becomes difficult to obtain.

Here, the barrel temperature is a temperature measured by a sensor provided on the inner wall of the barrel for each temperature control zone. A low barrel temperature means that the entire barrel is low regardless of the individual zones. means. When the materials are not kneaded, the temperature is close to the temperature of the electric heater incorporated in the barrel in a general extruder, and the extruder in which a heating medium is circulated through a pipe incorporated in the barrel is a hot extruder. The temperature is close to the temperature of the medium. When the material is kneaded, the barrel temperature is higher than the initial temperature setting because the material is affected by frictional heat of the material. The temperature setting generally means setting the electric heater or the heat medium before kneading to a specific temperature. When there are two or more temperature control zones, even if the temperature setting of each zone is the same, the material passing through the barrel is affected by the screw configuration, and the amount of frictional heat generated differs depending on the place where it is kneaded. In addition, the barrel temperature corresponding to each temperature adjustment zone also differs. The kneading temperature is originally the temperature of the material being kneaded, but in practice, the temperature of the material to be kneaded passing through the barrel cannot be measured. It means the temperature of the material to be kneaded measured by a transfer thermometer or a radiation thermometer.

Japanese Patent Application Laid-Open No. Hei 6-11895 discloses a method of lowering the temperature of a kneaded material, increasing the viscosity, increasing the shear, and improving the dispersion. In a continuous two-roll type kneader having two temperature control zones in one roll, in the embodiment, the surface temperature of the roll on the material input side is 60 ° C. and 30 ° C., and the surface temperature of the roll on the kneaded material discharge side is as follows. Are set to 45 ° C. and 30 ° C. Since this kneading machine is an open system and does not easily receive a load, it can be kneaded even at a low temperature. However, with the method described in this publication, as described above, the problems in terms of environment and safety have not been solved. Further, the continuous two-roll kneader is not suitable for industrial production because the material processing speed is 5 kg / hour and the productivity is low, although the equipment is expensive.

Further, Japanese Patent Application Laid-Open No. 2-66563 discloses that
It is disclosed that by kneading at a temperature 30 to 65 ° C. lower than the softening point of the binder resin, a toner excellent in dispersion can be obtained, but no kneading machine or kneading conditions are disclosed. Although it is not clear whether the temperature specified in the publication is the kneading temperature or the set temperature, a resin having a softening point of 132 ° C.
Since it is not kneaded at a kneading temperature of 5 ° C., it is assumed to be a set temperature. This publication is based on the idea of lowering the kneading temperature, increasing the viscosity of the material to be kneaded, and increasing the pigment dispersibility, but since there is no effective kneading method, a resin having a weight average molecular weight of 100,000 or more is used. Is used. That is, for example, it is possible to improve the dispersion of the pigment by using a resin that increases the viscosity of the material to be kneaded without setting the temperature to 70 ° C. or lower. However, the resin is limited. ing.

[0009]

The problem to be solved by the present invention is that the pigment is not scattered, is safe, can be employed industrially, and has good quality such as dispersibility and transparency. To provide a method for producing a resin coloring composition, specifically, to provide a method for producing a resin coloring composition in a continuous kneader, without coarse particles, the average particle size of the pigment is small. It is in.

[0010]

Means for Solving the Problems The present inventor has conducted intensive studies in view of such a situation, and as a result, among two or more temperature control zones of a single-screw extruder having a high dispersion function, a material inlet hole is provided. The temperature of the heat medium flowing through the pipe of the closest temperature control zone is set to a temperature lower than the softening point temperature of the thermoplastic resin by 40 ° C. or more to suppress the solidification of the pigment aggregates to form coarse particles, and a kneading machine. The viscosity of the material to be kneaded is increased, the shearing force is increased, and the dispersibility of the pigment is increased by reducing the coarse particles generated during kneading and the average particle size of the pigment. The inventors have found a method of improving transparency and coloring power, and have completed the present invention.

That is, in order to solve the above-mentioned problems, the present invention uses a single-screw extruder having two or more temperature control zones in which a pipe through which a heat medium flows through a barrel and having a high dispersion function. In a method of producing a colored resin composition in which the thermoplastic resin and the pigment are kneaded and the pigment is dispersed in the thermoplastic resin, the heat medium of the heat medium to be passed through the pipe of the temperature control zone closest to the material charging hole. Provided is a method for producing a colored resin composition, wherein the temperature is set to a temperature lower by at least 40 ° C. than the softening point temperature of a thermoplastic resin.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, a twin-screw extruder, which is superior in dispersibility of a pigment in a kneaded product as compared with a single-screw extruder, requires setting a barrel temperature near or above the softening point of the resin. General. The barrel of the twin-screw extruder has a built-in electric heater and a cooling water pipe for temperature control in case of excessive temperature rise, but the barrel temperature is set to 70 ° C or less. It is rare to do so. Even if the temperature is set at 70 ° C. or lower, the load increases due to the low temperature and high viscosity of the material to be kneaded, and the screw cannot be rotated. The twin-screw extruder uses a narrow gap between the barrel inner wall and the end of the screw element to disperse the pigment,
The structure is easy to apply a load.

The single-screw extruder having a high dispersing function used in the production method of the present invention has a higher porosity than the twin-screw extruder, and has the same length (L) as the length of the kneading portion of the screw. The ratio (L / D) to the diameter (D) of the ding screw is in the range of 11 to 22, and the screw is short, so that the load on the material to be kneaded is small and kneading at a lower temperature is possible. In addition, this single-screw extruder having a high dispersion function moves a massive kneaded material between a pin installed on the inner wall of the barrel and a screw that rotates and moves back and forth, and by a shear stress of the kneaded material itself. Is a device capable of dispersing a pigment. At this time, even at a low temperature setting, the material to be kneaded self-heats, so that the temperature becomes equal to or higher than the softening point of the resin, and the resin can be melted.

The single screw extruder having the high dispersing function may have at least two temperature control zones, and the number of the temperature control zones is not particularly limited. If they are different, the number of heat medium circulating devices for feeding the heat medium is also necessary, so that it cannot be said that a larger number is preferable. Therefore, it is preferable that the number of temperature control zones through which heat mediums having different temperatures are circulated is three to five. The temperature adjustment zone near the material charging hole has a lower temperature than the other temperature adjustment zones. Since the pigment dispersion differs depending on the chemical properties and physical properties of the thermoplastic resin to be used, the temperature cannot be clearly defined, but it is preferable to set the temperature at least 40 ° C. lower than the softening point temperature of the thermoplastic resin to be used. 6 degrees above the softening point temperature of the thermoplastic resin used.
It is particularly preferable to set the temperature at 0 ° C. or lower. As a result, since the resin is not plasticized immediately after the material is injected into the material charging hole, the pigment aggregates are loosened during that time, so that the phenomenon that the pigment aggregates are solidified to form coarse particles can be suppressed, and the dispersibility can be reduced. Can be increased. In this case, also in the other temperature adjustment zones, similarly, it is preferable to set the temperature to be lower than the softening point temperature of the thermoplastic resin to be used by 40 ° C. or more, and to be 60 ° C. lower than the softening point temperature of the thermoplastic resin to be used. It is particularly preferable to set the temperature to a lower temperature.
If there are three temperature control zones, it is preferable that the temperature of the heat medium in the temperature control zone closest to the outlet be slightly higher than the temperature of the heat medium in the other temperature control zones. In other words, it is preferable to set or adjust the temperature of the heating medium so that the kneading temperature of the material to be kneaded is 10 to 30 ° C. higher than the softening point temperature of the thermoplastic resin used. This is because it is necessary to raise the kneading temperature once to completely melt the resin before discharging the kneaded material. The softening point of the resin in the present invention is determined by JIS K
This is a value measured by the method specified in 2207.

FIG. 1 shows a schematic diagram of a single-screw extruder having three temperature control zones and having a high dispersion function, and the divisions (1, 2, 3) of the temperature control zones.

The heat medium circulated in the pipe built in the barrel may be a conditioned water or oil, but may be a refrigerant having high cooling efficiency, and is sent to the pipe by a heat medium circulation device. In the case of the former water, it is possible to control the temperature from normal temperature to 140 ° C. by applying pressure, and in the latter case, it is possible to use antifreeze-added water, for example, from 0 ° C. to 30 ° C.
It is also possible to control the temperature at 0 ° C or at 0 ° C or less. It is preferable to select an appropriate heat medium and heat medium supply device so as to set the temperature of the temperature adjustment zone and keep the temperature constant.

As a commercially available single-screw extruder having two or more temperature control zones having a built-in pipe for flowing a heat medium through a barrel used in the production method of the present invention and having a high dispersion function, Bus ( Buss) Co-Kneader.

The co-kneader manufactured by Buss Inc. comprises a single-screw screw, a gear box, a drive connection, a barrel having two or more temperature control zones, a base in which a pipe for temperature control and the like are housed, and a screw. The kneading element of
Improving kneading efficiency by using a screw that has a flight with three gaps per revolution and moves back and forth simultaneously with rotation, and the action of this gap and pins arranged in three rows on the inner wall of the barrel Can be done.

When kneading a thermoplastic resin and a powdered pigment with an extruder, particularly in the case of an organic pigment which is said to be difficult to disperse, it is important to sufficiently knead and extrude the dispersion in consideration of its dispersing mechanism. In a colored resin composition evaluated to have poor pigment dispersibility, pigment aggregates are generally solidified in the resin and remain as coarse particles of 50 μm to 100 μm or more, and the average particle size of the pigment is reduced. There are no cases. The former is a factor that remains in the final product and impairs smoothness, and the latter is a factor that makes it impossible to obtain coloring power and transparency. In the pigment dispersibility evaluation test described below,
When the thin colored film is observed with an optical microscope, the presence of countless pigment particles of about 1 to about 10 μ means that the average particle size of the pigment is not reduced.

The former cause of the generation of coarse particles is considered as follows. Immediately after the synthesis, the pigment
Although it is primary particles of about μm, secondary aggregation occurs during the drying process,
Furthermore, the powder aggregates during storage and transportation, and a general powder pigment contains 10% or more of pigment aggregates having a size of 10 μm or more, or several percent of pigment aggregates having a size of 50 μm or more.
Therefore, in kneading with an extruder, first, a device for loosening pigment aggregates is required. Such a powder pigment and resin,
If a screw element with a strong kneading function is placed near the injection hole or kneaded by an extruder with a high barrel temperature near the injection hole, it is compressed and solidified without sufficiently loosening the pigment aggregates, resulting in coarse particles. Becomes Therefore, when the material is introduced through the introduction hole, it is important to first loosen the pigment aggregates.

In order to reduce the average particle size of the pigment,
It is effective to keep the temperature of the material to be kneaded as low as possible, increase the viscosity of the material to be kneaded, and apply a strong shear force to knead the material. The production method of the present invention is a method capable of enhancing pigment dispersibility by sufficiently considering a pigment dispersion mechanism in an extruder.

As a specific method for improving the dispersibility of the pigment, there are generally used a method of constructing a screw by using many elements having a strong kneading function, a method of increasing the rotational speed of the screw, a method of kneading at a low temperature, and the like. Is mentioned. However, the optimum screw configuration differs depending on the kneading material, and it takes skill and trial and error to assemble the screw. In addition, the method of kneading at a high speed or the method of kneading at a low temperature is often difficult due to structural problems of the extruder.

Further, when these methods are employed without sufficiently considering the pigment dispersion mechanism, there are many cases where the pigment dispersibility is rather lowered. In the screw configuration, if an element with a strong kneading function is frequently used near the material charging hole, or if the screw rotation speed is increased, the pigment aggregates are compressed, solidified, and coarsened immediately after the material is charged into the extruder. Easy to form particles. In many cases, the particles are not miniaturized as they are and are discharged from the discharge holes while being mixed in the kneaded material. Under these conditions,
Since the heat generation is large, the viscosity of the material to be kneaded becomes low, the shearing force due to the rotation of the screw is not applied, and the average particle size of the pigment does not become small. Also, when the kneading temperature is lowered, the formation of coarse particles is suppressed and the viscosity of the material to be kneaded is high, so that a strong shearing force is applied and the average particle size of the pigment is reduced. However, since the resin may remain unmelted, it may be used as a colorant or compound after kneading, such as mixing with the resin according to the intended use, and kneading may cause clogging of the extruder. Become. Alternatively, in the case of molding with a molding machine in addition to the resin directly, it may appear as lumps on the molded product. Therefore, it is necessary to raise the temperature once to melt the unmelted resin before discharging the kneaded material.

FIG. 2 shows the relationship between the positions of the screw element and the drawing ring inside the barrel of the single screw extruder.

The screw structure of a single screw extruder having a high dispersing function is based on the fact that an element having a strong kneading function or an element having a function of retaining a material in a barrel and extending a kneading time is frequently used. It is preferable because the dispersibility can be improved. However, it is preferable that the screw element installed in the temperature adjustment zone (A) closest to the material charging hole should not have a strong kneading function.
After the resin is plasticized and melted, it is preferable to set the viscosity of the kneaded material to be high because the shearing force is high and the average particle size of the pigment is small. Therefore,
It is preferable to set the temperature of the second and subsequent temperature control zones to a low temperature from the viewpoint of improving the dispersibility. In the second and subsequent temperature adjustment zones, it is preferable that the screw configuration also uses many elements having a strong kneading function. In addition, ring-shaped drawing rings (6, 7) are spaced apart from each other on the inner wall of the barrel for the purpose of damming and retaining the material to be kneaded and extending the kneading time.
It is preferable that two or three or more elements having a strong kneading function are continuously used for the screw in the portion (B) near the material charging hole from the position of the drawing ring.

As the thermoplastic resin used in the production method of the present invention, polyethylene, polypropylene, polystyrene, ABS resin, polymethyl methacrylate, polyvinyl chloride, polycarbonate, nylon, polyester,
And a low polymer thereof, a modified resin obtained by adding an unsaturated fatty acid, vinyl acetate, acrylic acid, or the like thereto, or a mixture thereof. When two or several kinds of thermoplastic resins are mixed and used,
Although the softening point temperature cannot be strictly defined, in the present invention, a weighted average value obtained from individual softening point temperatures and mixing ratios of a plurality of thermoplastic resins to be used is defined as the softening point temperature. However, it is preferable to set the temperature of the heat medium in the temperature control zone to a low temperature within a range in which the single-screw extruder having a high dispersion function is not overloaded, since the dispersion of the pigment can be increased. Further, in order to completely melt a thermoplastic resin having a high softening point, for example, in the case of a single-screw extruder having a high dispersion function having three temperature control zones, the heat of the temperature control zone closest to the discharge port is used. It is preferable to consider the temperature of the medium, such as setting or adjusting the temperature to be 10 to 30 ° C. higher than the softening point of the thermoplastic resin having the highest softening point, among the plurality of thermoplastic resins used. .

The pigment used in the production method of the present invention includes:
There are organic pigments, inorganic pigments, extender pigments, metal powders, and the like.
As organic pigments, for example, azo lake, insoluble azo,
Azo pigments such as condensed azo; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; serene pigments such as anthraquinone, perinone and perylene; condensed polycyclic pigments such as quinacridone, isoindolinone, and dioxazine.

As the inorganic pigment, for example, titanium oxide,
Titanium pigments such as titanium yellow; red iron oxide pigments such as red iron oxide and yellow iron oxide; chromate pigments such as graphite and chromium vermillion; aluminate pigments such as cobalt blue; carbon black; No.

Examples of the extender include calcium carbonate, aluminum silicate, silica sand, calcium hydroxide, talc, clay, and mica.

Further, examples of the metal powder include brass powder and aluminum powder.

The proportion of the organic pigment to 100 parts by weight of the resin is preferably in the range of 5 to 150 parts by weight. Similarly,
The use ratio of the inorganic pigment is preferably in the range of 5 to 400 parts by weight. In addition, since the load on the single-screw extruder having a high dispersing function is higher as the use ratio of the pigment is higher, it is preferable to set the temperature of the heat medium in the temperature adjustment zone higher than when the use ratio of the pigment is lower. . However, after the thermoplastic resin is plasticized, the higher the proportion of the pigment used, the more frictional heat is generated, so that the kneading temperature of the material to be kneaded tends to increase. In that case, it is preferable to lower the temperature of the heat medium in the temperature adjustment zone.

In addition to the pigment and the resin, auxiliary agents such as a pigment dispersing agent, an antistatic agent, a charge controlling agent, and a lubricant may be added to the colored resin composition according to the use of the colored resin composition. it can.

It is preferable that the pigment and the resin are preliminarily mixed before being charged into the single screw extruder. There are two types of resin, pellets and powders.To uniformly mix the pigment and the resin, use a powdery resin. It is preferable to use it in a powder state. Since the mixture of the powdery resin and the pigment has a low bulk specific gravity, the mixture is scattered or the amount supplied to the extruder is limited. Therefore, it is preferable to preliminarily mix using a vertical high-speed mixer, semi-melt the resin by the frictional heat, adhere pigments to the resin surface, or adhere resins to each other, and granulate lightly. In particular, since organic pigments have a low bulk specific gravity, if this method is adopted and, for example, 100 parts of an organic pigment and 100 parts of a resin are mixed to form a material, a mixture having a bulk specific gravity of 0.2 to 0.4 is used. It is desirable to granulate lightly to have a bulk specific gravity of 0.4 to 0.6 before applying to the production method of the present invention.

The colored resin composition obtained by the production method of the present invention may be pulverized and classified, and then used as it is as a colorant for a thermoplastic resin without further processing, or may be used as a thermoplastic resin colorant. After mixing with an agent or the like, the mixture is kneaded again with a single-screw extruder or a twin-screw extruder, and shaped to obtain a pellet-like or granular colorant for a thermoplastic resin. Further, after mixing this colored resin composition with a thermoplastic resin and a charge controlling agent, the mixture was kneaded again with a twin-screw extruder or the like, and the mixture was further crushed to form a 5-1.
It can be pulverized to 0 μm and classified to obtain an electronic toner.

[0035]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited by these Examples. In the examples, “parts” and “%” are based on weight.

<Example 1> 100 parts of powdered polyethylene wax (molecular weight 6,400, softening point 110 ° C) and 100 parts of disazo yellow pigment (Pigment Yellow TRV-2: Sanyo Dye Co., Ltd.) were mixed by heating. The mixture was stirred and mixed in a stirrer, and kneaded with a single-screw extruder (a co-kneader MDK-46 manufactured by Buss) having three temperature control zones and a high dispersion function. Water at 70 ° C. was passed through the pipes of three temperature control zones (hereinafter, referred to as temperature control zone 1, temperature control zone 2, and temperature control zone 3 from the zone closest to the material charging hole). . Immediately after supplying the material, the resin did not plasticize and the powdery material was discharged from the discharge port.However, when the material was filled in the cylinder, the resin plasticized due to frictional heat between the materials and melted from the discharge port The kneaded material was discharged. At this time, the temperature of the kneaded material was 123 ° C., and the discharge rate was 20 kg / hour. After the discharged kneaded material is rolled by cooling two rolls,
The resultant was pulverized by a rotary cutter pulverizer to obtain a small colorant base. When the pigment dispersibility of this colorant base was confirmed by the following evaluation method, the pigment dispersibility was acceptable. Therefore, 5 parts of the colorant base and 100 parts of the polyethylene resin were mixed by a tumbler, kneaded with a single screw extruder, extruded into a strand, and cut with a pelletizer to obtain a pellet-shaped yellow colorant for the polyethylene resin.

[Evaluation of Pigment Dispersibility] 10 parts of the flake-form colorant base obtained as described above and low density polyethylene 90
The mixture was kneaded with two rolls of 6 inches in diameter heated at 150 ° C. for 5 minutes to produce a yellow sheet having a thickness of 1 mm.

From the sheet thus obtained, about 1 mg
Cut out, placed on a slide glass, put a cover glass on top, heat-pressed at 230 ° C to form a film with a thickness of 15 to 20 μm, and the dispersion was the worst with a 100 × optical microscope. A visual field is selected, and the particle size of the solidified pigment particles having a particle size of 11 μm or more (indicated by a circle equivalent diameter, that is, represented by the diameter of a circle having an area equivalent to the particle area) within the visual field is individually determined using an image analyzer. I asked. This is 1
1 μm to 20 μm, obtain the number of particles for each fixed particle size range such as 21 μm to 30 μm, and sum all the values multiplied by the coefficient corresponding to the particle size range shown in Table 1,
This was defined as the area index of one sample. This operation was repeated 10 times, that is, the area index was determined for 10 samples,
The average value was defined as a colorant-based area index. In addition, the particle size of the largest coarse particle observed in the above 10 samples was defined as the largest coarse particle size, which was evaluated according to the rank shown in Table 1.
Table 2 shows the results of the pigment dispersibility in Example 1. The criteria for this colorant-based pigment dispersibility are that the area index is 200 or less and the maximum coarse particle diameter is 80 μm or less (from A1 to B
2) were evaluated as “○”, and the others were evaluated as “×”.

[0039]

[Table 1]

<Embodiment 2> In the first embodiment, the temperature of the water flowing through the pipes of the three temperature control zones was all 5
A small piece colorant base was produced in the same manner as in Example 1 except that the temperature was set to 0 ° C. With respect to the yellow colorant base thus obtained, the pigment dispersibility was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

<Embodiment 3> In Embodiment 1, the temperature of the water flowing through the pipes of the three temperature control zones was set to 2
A small piece of colorant base was produced in the same manner as in Example 1 except that the temperature was set to 0 ° C. With respect to the yellow colorant base thus obtained, the pigment dispersibility was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

<Example 4> In Example 1, the temperature of the water flowing through the pipes in the three temperature control zones was changed to 50 ° C. In the same manner as in Example 1, except that the temperature of the water flowing through the zone (temperature control zone 2) was 70 ° C., and the temperature of the water flowing through the zone close to the discharge port (temperature control zone 3) was 100 ° C. A flake-like colorant base was produced. With respect to the yellow colorant base thus obtained, the pigment dispersibility was evaluated in the same manner as in Example 1.
The results are shown in Table 2.

<Comparative Example 1> In Example 1, the temperature of the water flowing through the pipes in the three temperature control zones was 100 ° C., and the temperature of the water flowing through the zone close to the material inlet was 100 ° C. A small colorant was produced in the same manner as in Example 1, except that the water temperature of the sample was 70 ° C., and the temperature of the water flowing through the zone close to the discharge port was 30 ° C. The yellow colorant thus obtained was evaluated for pigment dispersibility in the same manner as in Example 1, and the results are shown in Table 2.

<Comparative Example 2> In Example 1, the temperature of the water flowing through the pipes of the three temperature control zones was all set to 1
A small piece of colorant was produced in the same manner as in Example 1 except that the temperature was changed to 00 ° C. The yellow colorant thus obtained was evaluated for pigment dispersibility in the same manner as in Example 1, and the results are shown in Table 2.

<Comparative Example 3> In Example 1, the temperatures of the water flowing through the pipes of the three temperature control zones were all set to 1
A small piece of colorant was produced in the same manner as in Example 1 except that the temperature was changed to 30 ° C. The yellow colorant thus obtained was evaluated for pigment dispersibility in the same manner as in Example 1, and the results are shown in Table 2.

[0046]

[Table 2]

Example 5 100 parts of a linear polyester resin (molecular weight 10,000, softening point 100 ° C.) and 100 parts of a quinacridone red pigment (KET RED 309: manufactured by Dainippon Ink and Chemicals, Inc.) Mix for 20 minutes with a mixer,
After being lightly granulated by the frictional heat generated at this time, the granulation was carried out at three temperature control zones, a single screw extruder (Buss Co., Ltd.) having a screw water cooling function and a high dispersion function. Kneading with a kneader MDK-46). Set the temperature of the water flowing through the pipe built into the screw to 0 ° C,
Water at 50 ° C. was circulated through all pipes in the temperature control zone. Immediately after supplying the material, the resin did not plasticize and the powdery material was discharged from the discharge port.However, when the material was filled in the cylinder, the resin plasticized due to frictional heat between the materials and melted from the discharge port The kneaded material was discharged. At this time, the temperature of the kneaded material was 138 ° C., and the discharge rate was 10 kg / hour. The discharged kneaded material was rolled with two cooling rolls, crushed with a rotary cutter, and further crushed with a knife-type crusher equipped with a 2 mm screen to obtain a powdery and granular electronic toner base (master batch). .

When the pigment dispersibility of this toner base was confirmed by the following evaluation method, the pigment dispersibility was acceptable. Therefore, 12 parts of this toner base, 100 parts of a linear polyester resin and 4 parts of a charge control agent (chromium salicylate complex) are mixed by a tumbler, kneaded by a twin screw extruder, extruded into a belt shape, and cooled and rolled by a steel belt cooler. , Coarsely crushed into small pieces, crushed and classified to 5-10
A red electronic toner having a size of μm was obtained.

A sample of about 1 mg was collected from the toner base obtained as described above, placed on a slide glass, a drop of toluene was dropped on the slide with a pipette, and the sample was swollen. And hot pressed at 200 ° C. to form a film having a thickness of about 10 μm.
A field of view having the worst dispersion is selected with an optical microscope at × 2, and the particle size of the solidified pigment particles having a particle size of 5 μm or more in this field of view (equivalent circle diameter, ie, the diameter of a circle having an area equivalent to the particle area) ) Were individually determined using an image analyzer. Next, the area index and the maximum coarse particle diameter were determined in the same manner as in Example 1 except that the number of small particles in the particle diameter range of 5 μm to 10 μm was determined. Table 3 shows the results of the pigment dispersibility in Example 5.
Shown in The criteria for determining the toner-based pigment dispersibility are:
The area index is 50 or less, the maximum coarse particle diameter is in the range of A1 to A3 (40 μm or less), and those in which 5 to 10 μm small particles satisfy any of 20 or less are evaluated as “○”. It was evaluated as "x".

<Embodiment 6> In Embodiment 5, the temperature of the water flowing through the pipes in the three temperature control zones was set to 10 ° C. In the same manner as in Example 5 except that the temperature of the water flowing through the zone (temperature control zone 2) was 30 ° C., and the temperature of the water flowing through the zone close to the discharge port (temperature control zone 3) was 50 ° C. , To produce a powdery toner base. The pigment dispersibility of the toner base thus obtained was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

<Comparative Example 4> In Example 5, the temperatures of the water flowing through the pipes of the three temperature control zones were all 7
A powdery and granular toner base was produced in the same manner as in Example 5 except that the temperature was changed to 0 ° C. The pigment dispersibility of the toner base thus obtained was evaluated in the same manner as in Example 5, and the results are shown in Table 3. The largest coarse particle is 6
0 μm or less, but many small particles of 5 to 10 μm,
The average particle size was not small, the transparency was inferior to that of Example 5, and this application was rejected.

<Comparative Example 5> In Example 5, the temperatures of the water flowing through the pipes of the three temperature control zones were all set to 1
A powdery and granular toner base was manufactured in the same manner as in Example 5 except that the temperature was changed to 00 ° C. The pigment dispersibility of the toner base thus obtained was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

<Comparative Example 6> In Example 5, the temperature of the water flowing through the pipes in the three temperature control zones was changed to 130 ° C. In the same manner as in Example 5 except that the temperature of the water flowing through the zone (temperature control zone 2) was 100 ° C., and the temperature of the water flowing through the zone close to the discharge port (temperature control zone 3) was 70 ° C. , To produce a powdery toner base. The pigment dispersibility of the toner base thus obtained was evaluated in the same manner as in Example 5.
Table 3 shows the results.

<Comparative Example 7> In Example 5, the same material was kneaded with a twin-screw extruder having six temperature control zones instead of a single-screw extruder having a high dispersion function. Kneading was performed at a screw rotation speed of 200 rpm at 70 ° C. in all six temperature control zones in which an electric heater for heating and a pipe for flowing cooling water were incorporated, but the operation was stopped due to torque over.

Comparative Example 8 A powdery toner base was manufactured in the same manner as in Comparative Example 7, except that the screw rotation speed was changed to 400 rpm. The pigment dispersibility of the toner base thus obtained was evaluated in the same manner as in Example 5, and the results are shown in Table 3.

[0056]

[Table 3]

[0057]

According to the production method of the present invention, a colored resin composition having excellent pigment dispersibility having a maximum of 80 μm or less in coarse particles can be obtained. Further, the colored resin composition obtained by the production method of the present invention is a thermoplastic resin film having smoothness, a coloring agent for molding an injection molded product, or
The present invention can be applied to an electronic color toner for forming a clear visible image on paper or an OHP film.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a single screw extruder having three temperature control zones.

FIG. 2 is a schematic diagram showing a positional relationship between a screw element and a drawing ring inside a barrel of a single screw extruder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature adjustment zone 1 2 Temperature adjustment zone 2 3 Temperature adjustment zone 3 4 Material input hole 5 Direction of material advance 6 Draw ring 1 7 Draw ring 2 A Temperature control zone closest to material input hole B Second and subsequent temperature control zones

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F070 AA11 AA12 AA41 AE04 FA03 FC05 4F201 AA49 AB12 AC04 AH81 AP05 BA01 BC01 BC13 BC15 BC17 BK02 BK13 BK25 BK74 BN12 BN30 BQ57

Claims (4)

[Claims] 1. A thermoplastic resin and a pigment are kneaded by using a single-screw extruder having two or more temperature control zones each having a built-in pipe through which a heat medium flows through a barrel and having a high dispersion function. In the method for producing a colored resin composition in which the pigment is dispersed in the thermoplastic resin, the temperature of the heat medium flowing through the pipe in the temperature control zone closest to the material charging hole is higher than the softening point temperature of the thermoplastic resin. A method for producing a colored resin composition, wherein the temperature is set to a temperature lower by at least 40 ° C. 2. The temperature setting of the heat medium flowing through the pipes of the temperature control zone closest to the material charging holes in the temperature control zone is lower than the temperature setting of the heat medium flowing through the pipes of the other temperature control zones. The method for producing a colored resin composition according to claim 1, wherein 3. The method for producing a colored resin composition according to claim 1, wherein the heat medium is a refrigerant. 4. The coloring according to claim 1, wherein the kneading function of the screw arranged in the temperature adjustment zone closest to the material charging hole is set weaker than the kneading function of the screw arranged in the other temperature adjustment zones. A method for producing a resin composition.