JPH08117578A - Method and apparatus for making aqueous emulsion of thermoplastic resin - Google Patents

Abstract

PURPOSE: To enable the inexpensive mass production of a high quality aqueous emulsion by a method in which an organic solvent is not used and resin particles are atomized. CONSTITUTION: An apparatus is concerned in which a raw material flow in which a thermoplastic resin and an aqueous solution of an emulsifier is mixed in a specified ratio is formed by combining a thermoplastic resin flow and an emulsifier aqueous solution flow, and the raw material flow is emulsified and dispersed by a rotary emulsification machine 5. The apparatus is equipped with a temperature control means 6 which adjusts the temperatures of the raw material flow, etc., so that an average temperature of the raw material flow is maintained at a temperature of the softening point of the thermoplastic resin or above from a point of time when the thermoplastic resin flow and the emulsifier aqueous solution flow are combined to a point of time when the combined flow comes out from a rotary emulsification machine 5 and a pressure control means 7 which adjusts the pressure of the raw material flow so that water in the raw material flow is prevented from boiling at a temperature of the raw material flow which is set by the temperature control means 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin obtained by emulsifying a water-insoluble thermoplastic synthetic resin or natural resin as fine particles in water. More specifically, the present invention relates to a method and an apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin suitable for producing a rosin sizing agent or the like used as an internal additive for paper in a papermaking process.

[0002]

2. Description of the Related Art Hitherto, as a method for producing an aqueous emulsion dispersion of a thermoplastic resin obtained by emulsifying a water-insoluble thermoplastic synthetic resin or natural resin as fine particles in water, JP-A 06-107903 has been known. As disclosed in the publication, a method using an organic solvent capable of dissolving a thermoplastic resin has been widely used.

In this manufacturing method, a thermoplastic resin to be an emulsified dispersion is previously dissolved in an appropriate organic solvent to prepare a resin solution. Then, a raw material liquid is prepared by mixing the resin solution with an emulsifier aqueous solution containing a surfactant. Then, this raw material liquid is press-fitted into the high-pressure emulsifier using an ultra-high pressure pump. The lower limit of pressurization by the ultra-high pressure pump is usually 10
0 to 1000 kgf / cm ² G, the upper limit is sometimes 200
It reaches 0 kgf / cm ² G.

The high-pressure emulsifier passes the raw material liquid pressurized by the ultra-high pressure pump through the gap between the cylinder and the plunger, and when the pressure is released after the passage, the resin is atomized by the action of the emulsifier. It is in the emulsified state. Then, when the raw material liquid in the emulsified state is depressurized to remove the organic solvent, fine particles of the solidified thermoplastic resin are emulsified and dispersed in water to obtain an aqueous emulsion dispersion of the thermoplastic resin.

[0005]

However, in the conventional manufacturing method using an organic solvent, the organic solvent recovery device for removing the organic solvent from the raw material liquid after the emulsification treatment by the high pressure emulsifier becomes expensive and the operating cost is high. There is a problem that it is bulky and the equipment becomes large due to the installation of the organic solvent recovery apparatus, and eventually there is a problem that the production cost of the aqueous emulsion dispersion increases.

Further, in the case of the conventional high pressure emulsifying machine in which the pressurized raw material liquid is passed through the gap between the cylinder and the plunger, in order to make the resin particles to be emulsified into finer particles, the space between the cylinder and the plunger is increased. It is necessary to miniaturize the gaps with high precision, and it is costly to process the cylinder and the plunger, and there is a problem that the apparatus cost is increased. Moreover, there is a problem that the plunger is easily worn by contact with the high-pressure raw material liquid, and the emulsification performance is easily deteriorated by the wear of the plunger.

Recently, there has been a call for reduction in the use of organic solvents from the viewpoint of occupational safety and health, and from that point as well, the development of a production method that does not require the use of organic solvents has been desired.

From such a background, using an existing Harrell type homogenizer or colloid mill as an emulsifying machine,
A method of making resin particles fine by means of mechanical shearing force and emulsifying and dispersing without using an organic solvent has also been studied. However, all of the existing Haller type homogenizers, colloid mills, etc., feed the raw material between the stator and the rotor while rotating the rotor by driving the rotor and the rotor facing each other at a minute interval. However, the resin particles in the raw material are miniaturized mainly by the shearing force that acts on the raw material by the rotating force of the rotor, and the resin particles are highly miniaturized due to the processing precision of the rotor and the stator. At the same time, it is difficult to increase the processing amount, and it is also difficult to increase the size.

Therefore, an object of the present invention is to solve the above-mentioned problems, and it is possible to highly miniaturize the resin particles without using an organic solvent, and to reduce the cost of equipment such as an emulsifying machine and the operating cost. Aqueous emulsion dispersion of a thermoplastic resin that is suitable for reduction and at the same time can respond to large size to increase the processing amount relatively easily and can mass-produce high quality aqueous emulsion dispersion at low cost. A liquid manufacturing method and apparatus are provided.

[0010]

The above object of the present invention is to include a thermoplastic resin flow obtained by heating a thermoplastic resin at a temperature above its softening point to reduce its viscosity to a predetermined level or less, and a temperature below the boiling point of water. Of the emulsifier aqueous solution heated to an appropriate temperature to form a raw material stream in which the thermoplastic resin and the emulsifier aqueous solution are mixed in a predetermined ratio, and the raw material stream is supplied to a rotary emulsifier The resin particles in the raw material are made into an emulsified state by atomizing the resin particles in the raw material by the shearing action in the emulsifier, and the resin particles contained by cooling the raw material stream after the emulsification treatment to a predetermined temperature by the rotary emulsifier to have a predetermined particle diameter. A method for producing an aqueous emulsion dispersion of a thermoplastic resin to obtain a finely divided emulsion dispersion, wherein a raw material stream formed by the confluence of the thermoplastic resin stream and an emulsifier aqueous solution stream is the thermoplastic resin stream. Emulsifier aqueous solution flow From the start of merging until the time of leaving the rotary emulsifier, while adjusting the temperature so that the average temperature is maintained at a predetermined temperature above the softening point of the thermoplastic resin, water in the raw material in the adjusted temperature environment It is achieved by a method for producing an aqueous emulsion dispersion of a thermoplastic resin, which is characterized by controlling the pressure so as not to boil.

Further, in the above-mentioned method for producing an aqueous emulsion dispersion of a thermoplastic resin, in the rotary emulsifying machine, crushing tooth rows in which crushing teeth are annularly arranged are concentrically arranged on a disk-shaped substrate portion. And a crushing tooth row in which crushing teeth arranged in an annular shape between the stator and the crushing tooth rows adjacent to each other of the stator are arranged in an annular shape correspond to the arrangement of the crushing tooth rows on the stator. And a rotor that is concentrically arranged on the disk-shaped base plate and is driven to rotate, and the raw material insertion groove between adjacent crushing teeth in each crushing tooth row on the stator and the rotor is The tooth row on the outer peripheral side is set smaller, and by flowing the raw material from the center to the outer periphery between the stator and the rotor, the resin particles in the raw material are miniaturized to obtain an emulsion dispersion. Also, the above object can be achieved.

Further, the above-mentioned object of the present invention includes a resin supply passage for supplying a thermoplastic resin whose viscosity has been lowered below a predetermined value by heating the thermoplastic resin to a softening point or more at a constant flow rate, and a surfactant. Along with the emulsifier aqueous solution supply channel for supplying the emulsifier aqueous solution heated at an appropriate temperature equal to or lower than the boiling point of water at a constant flow rate, the thermoplastic resin and the emulsifier aqueous solution are combined by combining the resin supply channel and the emulsifier aqueous solution supply channel. A mixing supply path for generating and supplying a raw material stream mixed in a ratio, a rotary emulsifier for atomizing resin particles in the raw materials supplied from the mixing supply path by a shearing action or the like to an emulsified dispersion state, and the heat The raw material stream and the heat so that the average temperature of the raw material fluid is maintained at a predetermined temperature equal to or higher than the softening point of the thermoplastic resin from the start of the joining of the plastic resin stream and the emulsifier aqueous solution stream to the time of leaving the rotary emulsifier. Temperature control means for adjusting the temperatures of the plastic resin flow and the emulsifier aqueous solution flow, and the thermoplastic resin flow and the emulsifier aqueous solution flow so that the water in the raw material flow does not boil at the temperature of the raw material flow set by the temperature control means. Of the thermoplastic resin water system comprising a pressure control means for adjusting the pressure of the raw material stream from the start of merging of the rotary emulsifier to the time of leaving the rotary emulsifier, and a cooling means for cooling the raw material stream exiting the rotary emulsifier. This is achieved by an apparatus for producing an emulsified dispersion.

Further, in the above-described apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin, in the rotary emulsifying machine, crushing tooth rows in which crushing teeth are annularly arranged are concentrically arranged on a disk-shaped substrate portion. And a crushing tooth row in which crushing teeth arranged in an annular shape between the stator and the crushing tooth rows adjacent to each other of the stator are arranged in an annular shape correspond to the arrangement of the crushing tooth rows on the stator. And a rotor that is concentrically arranged on the disk-shaped base plate and is driven to rotate, and the raw material insertion groove between adjacent crushing teeth in each crushing tooth row on the stator and the rotor is The tooth row on the outer peripheral side is set smaller, and by flowing the raw material from the center to the outer periphery between the stator and the rotor, the resin particles in the raw material are miniaturized to obtain an emulsion dispersion. The above-mentioned object can be achieved.

Further, in the above-mentioned apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin, the temperature control means applies a heat medium to each of the resin supply passage, the emulsifier aqueous solution supply passage, the mixing supply passage, and the rotary emulsifier. The above object can be achieved even if the structure is equipped with a flow jacket and the temperature of the raw material flow is adjusted by adjusting the temperature of the heat medium and adjusting the flow rate.

Further, in the above-mentioned apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin, as the pressure control means, the pressure control means is provided after the cooling means to control the pressure of the raw material flow in the rotary emulsifying machine or the like. The configuration using a pressure valve can also achieve the above object.

[0016]

According to the above constitution of the present invention, the thermoplastic resin is
It is not dissolved in an organic solvent and is mixed with an aqueous solution of an emulsifier only by heating to reduce the viscosity, and is supplied as a raw material to a rotary emulsifier, and the resin particles in the raw material are sheared by the rotary emulsifier. Since the fine particles are formed into an emulsified state, there is no need for an organic solvent recovery device that increases the device cost and the operating cost.

Moreover, the raw materials supplied to the rotary emulsifier are
The average temperature is maintained above the softening point of the contained thermoplastic resin, and the pressure in the raw material is kept high so that the water does not boil, so that the emulsification treatment by the rotary emulsifier works efficiently. The properties of the raw material are controlled as described above, and inconveniences such as cavitation due to boiling of water in the raw material are prevented in the rotary emulsifier, so the emulsification performance of the rotary emulsifier is fully demonstrated. Can be made.

In the rotary emulsifying machine, a stator having a structure in which crushing tooth rows in which crushing teeth are annularly arranged are concentrically arranged, and an annular groove between adjacent crushing tooth rows of the stator is provided. A rotary emulsifying machine having a configuration in which a crushing tooth row in which crushing teeth to be fitted are arranged in an annular shape is concentrically arranged corresponding to the arrangement of the crushing tooth rows on the stator and is driven to rotate. In the case of using, the relatively rotating stator and a large number of crushing teeth of the rotor exert a high shearing force on the resin particles and at the same time a high frequency pressure fluctuation. Each of the fluctuations works effectively for atomizing the resin particles, and it is possible to achieve sufficiently high atomization without miniaturizing the gaps in which the raw material flows between the stator and the rotor. . And this means that if the same degree of fineness is achieved as compared with the conventional device, the processing accuracy and assembly accuracy of the stator and rotor can be relaxed, and the processing capacity is improved. It means that it can be done. Further, if the stator and the rotor have a structure in which independent ring-shaped members are connected and integrated for each crushing tooth row, the stator and the rotor can be relatively easily and inexpensively increased in size and processed. The amount can be increased.

Therefore, according to the manufacturing method and apparatus having the above-mentioned constitution, the resin particles can be highly miniaturized without using an organic solvent, and moreover, it is suitable for reducing the equipment cost such as an emulsifying machine and the operating cost. At the same time, it is possible to relatively easily comply with the increase in size for increasing the amount of treatment, and it becomes possible to mass-produce a high-quality aqueous emulsion dispersion at low cost.

[0020]

EXAMPLE FIG. 1 shows a schematic structure of an example of an apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin according to the present invention.

As shown in FIG. 1, a manufacturing apparatus 1 according to an embodiment of the present invention has a resin supply path for supplying a constant flow rate of a thermoplastic resin whose viscosity is lowered below a predetermined value by heating it above its softening point. 2, an emulsifier aqueous solution supply passage 3 for supplying a constant flow rate of an emulsifier aqueous solution containing a surfactant and heated to an appropriate temperature lower than the boiling point of water, and the resin supply passage 2 and the emulsifier aqueous solution supply passage 3 are joined together. The thermoplastic resin and the emulsifier aqueous solution are mixed and mixed at a predetermined ratio to generate and supply a raw material flow, and the resin particles in the raw material supplied from the mixed supply passage 4 are atomized by a shearing action or the like. The average temperature of the raw material fluid is the average temperature of the raw material fluid from the start of joining the thermoplastic resin flow and the emulsifier aqueous solution flow through the mixing / supplying path 4 to the rotary emulsifier 5 in an emulsified dispersion state. Of thermoplastic Temperature control means 6 for adjusting the temperatures of the raw material stream, the thermoplastic resin stream and the emulsifier aqueous solution stream so as to be maintained at a predetermined temperature above the chemical conversion point, and the raw material stream at the temperature of the raw material stream set by the temperature control means 6. Pressure control means 7 for adjusting the pressure of the raw material stream from the start of the joining of the thermoplastic resin flow and the emulsifier aqueous solution flow to the time of leaving the rotary emulsifier so that the water therein does not boil; and the rotary emulsifier. 5, a cooling means 8 for cooling the raw material stream and an emulsion dispersion liquid storage tank 9 for storing the aqueous emulsion dispersion liquid of the thermoplastic resin cooled to a predetermined temperature by the cooling means 8. .

Here, in the resin supply passage 2, a resin tank 22 for storing a thermoplastic resin 21 which has been initially heated to an appropriate temperature above the softening point and has a viscosity below a predetermined value, and the inside of the resin tank 22. Resin pump 23 for sending out the thermoplastic resin of the same to the resin supply path 2 at a constant flow rate, and the resin pump 2
3 is equipped with a resin flow meter 24 for detecting the flow rate of the thermoplastic resin flow flowing in the resin supply passage 2 in order to control the discharge flow rate of No. 3, and is heated to an appropriate temperature above the softening point to have a predetermined viscosity. The thermoplastic resin set below can be supplied at a constant flow rate.

In the emulsifier aqueous solution supply passage 3, an emulsifier tank 32 for storing an emulsifier aqueous solution 31 containing a surfactant and initially heated to an appropriate temperature below the boiling point of water is stored.
And an emulsifier pump 33 for delivering the emulsifier aqueous solution 31 in the emulsifier tank 32 to the emulsifier aqueous solution supply passage 3 at a constant flow rate, and a flow in the emulsifier aqueous solution supply passage 3 to control the discharge flow rate of the emulsifier aqueous solution 33. An emulsifier flow meter 34 for detecting the flow rate of the emulsifier aqueous solution is provided, and the emulsifier aqueous solution heated to an appropriate temperature below the boiling point of water can be supplied at a constant flow rate.

The mixing supply path 4 joins the resin supply path 2 and the emulsifier aqueous solution supply path 3 and guides them to the raw material supply port of the rotary emulsifying machine 5. For example, a T-joint or the like is appropriately improved. It has a structure.

In the case of this embodiment, the rotary type emulsifying machine 5 includes, as shown in FIGS. 2 and 3, a substantially disk-shaped stator 52 in a cylindrical case body 51. The rotor 53 is arranged so as to face the center axis of the disk. The stator 52 has a structure in which crushing tooth rows 521 in which crushing teeth 520 are arranged in an annular shape are concentrically arranged in three rows on a disk-shaped substrate portion. In addition, a raw material supply port 54 is formed in the center of the stator 52 so as to penetrate the case body 51 and communicate with the mixing supply path 4.

On the other hand, the rotor 53 is the stator 52.
The crushing tooth row 531 formed by arranging the crushing teeth 530 that fit in the annular groove between the adjacent crushing tooth rows 521 in the annular shape is the stator 52.
Corresponding to the upper crushing tooth row 521, it has a configuration in which four rows are concentrically arranged on a disk-shaped substrate portion. And
As shown in FIG. 2, a drive shaft 55, which is rotationally driven by a rotational drive means (not shown) (for example, a motor), rotatably penetrates through the case body 51 at the center of the rotor 53. Are linked together.

Also, as shown in FIG.
And in the rotor 53, adjacent crushing tooth rows 521,
The annular groove between 531 and the grooves 523, 533 between the crushing teeth 520, 530 circumferentially adjacent to each other in the crushing tooth row 521, 531 both function as a raw material insertion groove that serves as a flow path for the raw material flow. Further, a raw material discharge port 56 for discharging the raw material flow after the emulsification treatment is provided on the outer peripheral portion of the case body 51.
Is equipped.

In the crushing tooth rows 521, 531 on the stator 52 and the rotor 53, the raw material insertion grooves 523, 533 between the crushing teeth 520, 530 adjacent to each other in the circumferential direction.
Are set to be smaller toward the tooth row on the outer peripheral side. Further, although not shown, these 52 and the rotor 53 are
A plurality of ring-shaped members that provide the crushing tooth rows 521 and 531 are fitted, and one ring-shaped member that is a component provides one crushing tooth row. In this way, by dividing and manufacturing each crushing dentition,
It becomes possible to easily and inexpensively manufacture a structure in which crushing tooth rows having different pitches between adjacent crushing teeth are arranged concentrically.

In the rotary emulsifying machine 5 having such a structure, the raw material flow supplied from the raw material supply port 54 arranged at the center is the stator 5 as shown by the solid line arrow in FIG.
2 and crushing teeth 520, 530 protruding from the rotor 53
It flows through the raw material insertion groove between them to the raw material discharge port 56 on the outer peripheral portion of the case main body 51, and while flowing from the raw material supply port 54 to the raw material discharge port 56, a high shearing force generated by the rotation of the rotor 53 and When exposed to high-frequency pressure fluctuations, the high shearing force, high-frequency pressure fluctuations, and the synergistic action of the surfactant in the emulsifier effectively atomize and disperse the resin particles in the raw material flow. .

The temperature control means 6 includes the resin supply passage 2
Each of the emulsifier aqueous solution supply path 3, the mixing supply path 4, and the rotary emulsifier 5 is equipped with a jacket (not shown) through which a heat medium flows, and the heat medium in the heat medium storage tank 61 is adjusted to a predetermined temperature. Of the thermoplastic resin flow in the resin supply passage 2 and the emulsifier by adjusting the temperature and the flow rate of the heat medium in the heat medium storage tank 61. The temperature of the aqueous emulsifier solution in the aqueous solution supply path 3 and the temperature of the raw material flow in the mixing supply path 4 and the rotary emulsifier 5 are maintained at desired temperatures. The inventors of the present application investigated various known heating methods such as electric heating in order to find an optimum heating means as the temperature control means 6. As a result, in the apparatus configuration as described above, there is a method in which a heating medium (heating steam, heating oil, etc.) is flowed to the outside of the flow path as a double pipe structure in which each supply path and the rotary emulsifier are covered with a jacket. After confirming that it is excellent in terms of heating rate, easiness of temperature maintenance, uniform temperature distribution, economy of operating cost, etc., the temperature control means 6 uses a heat medium as described above. I decided to do it. For the initial heating of the thermoplastic resin supplied to the resin tank 22 and the initial heating of the emulsifier aqueous solution supplied to the emulsifier tank 32, a heat source different from the temperature control means 6 may be used. Means 6
May be used.

In the case of this embodiment, the pressure control means 7 is provided at the subsequent stage of the cooling means 8 and controls the pressure of the raw material flow in the rotary emulsifying machine 5 and the mixing supply path 4 by a back pressure valve. Is.

The cooling means 8 reduces the temperature of the emulsified high-temperature raw material stream (which is already an aqueous emulsified dispersion liquid) discharged from the rotary emulsifier 5 to a temperature below the boiling point of water at atmospheric pressure. The material is cooled to a temperature, and the pressure control means 7 provided downstream of the cooling means 8 prevents boiling of water in the raw material stream when the pressure of the raw material stream is reduced to atmospheric pressure. In practice, the cooling means 8 cools the raw material stream discharged from the rotary emulsifying machine 5 to the storage temperature in the emulsion dispersion liquid storage tank 9. A known heat exchange mechanism is used as the cooling mechanism.

The method for producing an aqueous emulsion dispersion of a thermoplastic resin according to the present invention is carried out by using the above-mentioned apparatus 1 for producing an aqueous emulsion dispersion. The manufacturing method thereof will be described below.

The thermoplastic resin 21 whose viscosity has been lowered below a predetermined value by heating above the softening point by initial heating is stored in the resin tank 22 and heated below the boiling point of water in the atmospheric pressure environment by initial heating. The emulsifier aqueous solution is stored in the emulsifier tank 32.

Then, the resin pump 23 and the emulsifier pump 33 are operated, and the thermoplastic resin heated above the softening point temperature is supplied at a predetermined constant flow rate through the resin supply passage 2
Flowing into the emulsifier aqueous solution supply path 3 at a predetermined constant flow rate, which is heated to an appropriate temperature (preferably as high as possible) equal to or lower than the boiling point of water. The stream and the emulsifier aqueous solution stream are combined to form a raw material stream in which the thermoplastic resin and the emulsifier aqueous solution are mixed at a predetermined ratio, and the raw material stream is supplied to the rotary emulsifier 5.

The temperature control means 6 is operated at the time of starting the supply of the thermoplastic resin to the resin supply passage 2 or immediately before that, so that the average temperature of the raw material flow is equal to that of the thermoplastic resin flow and the emulsifier. From the start of merging with the aqueous solution to the point of leaving the rotary emulsifier, the temperature of the thermoplastic resin flow is adjusted and the temperature of the aqueous emulsifier solution is adjusted so as to be maintained at a predetermined temperature above the softening point of the thermoplastic resin. Adjust the temperature of the raw material flow.

The pressure control means 7 is also operated early so that the water in the raw material does not boil from the time when the flow of the thermoplastic resin flow and the flow of the emulsifier aqueous solution start to the time when the water flows out of the rotary emulsifier. First, the pressure in the flow path is controlled under pressure.

The raw material flow supplied to the rotary emulsifier 5 is, as shown in FIGS. 2 and 3, previously, the crushing teeth 520, 53 protruding from the stator 52 and the rotor 53.
The high shear force generated by the rotation of the rotor 53 while flowing through the raw material insertion groove between 0 to the raw material discharge port 56 at the outer peripheral portion of the case main body 51, while flowing from the raw material supply port 54 to the raw material discharge port 56. When exposed to high-frequency pressure fluctuations, the high shear force, high-frequency pressure fluctuations, and the synergistic action of the surfactant in the emulsifier effectively atomize and disperse the resin particles in the raw material flow. It

The raw material discharge port 56 of the rotary emulsifying machine 5
The high-temperature and high-pressure emulsified dispersion liquid discharged from the cooling means 8 is cooled by the cooling means 8 to an appropriate temperature below the boiling point of water at atmospheric pressure (usually,
It is cooled to room temperature), reduced to atmospheric pressure by the pressure control means 7, and stored in the emulsion dispersion liquid storage tank 9.

According to the above-mentioned method for producing an aqueous emulsified dispersion liquid using the production apparatus 1, the thermoplastic resin is not dissolved in the organic solvent and is mixed with the emulsifier aqueous solution only by heating to reduce the viscosity. Is supplied as a raw material to the rotary emulsifier 5 and the resin particles in the raw material are atomized into an emulsified state by a shearing action or the like in the rotary emulsifier 5, which causes an increase in the apparatus cost and the operating cost. No organic solvent recovery device is required.

Moreover, the raw material supplied to the rotary emulsifier 5 is maintained at an average temperature above the softening point of the thermoplastic resin contained therein by the temperature control means 6, and the water in the raw material is removed by the cooling means 8. The property of the raw material is controlled so that the emulsification treatment by the rotary emulsifier 5 works efficiently such as keeping the pressure high so as not to boil, and the water in the raw material in the rotary emulsifier 5 is controlled. Since the occurrence of inconveniences such as cavitation due to boiling of water is prevented, the emulsification processing performance of the rotary emulsifying machine 5 can be sufficiently exhibited.

The rotary type emulsifying machine 5 is provided with the crushing teeth 5
A ring-shaped crushing tooth row 521 in which 20 pieces are arranged in an annular shape is provided with a stator 52 and a crushing tooth 530 that fits in an annular groove between adjacent crushing tooth rows 521 of the stator 52. The crushing tooth row 531 arranged side by side comprises a rotor 53 which is concentrically arranged and rotationally driven corresponding to the arrangement of the crushing tooth row 521 on the stator 52. Many crushing teeth 520, 5 of the rotor 53
The high shearing force acts on the resin particles at the same time as the high shearing force acts on the resin particles by 30, and each of the high shearing force and the high frequency pressure variation effectively works for atomizing the resin particles, and the stator 52 It is possible to achieve a sufficiently high degree of fineness without making the gaps between the rotor 53 and the rotor 53, through which the raw material flows, finer. And, this means that the machining accuracy and the assembly accuracy of the stator 52 and the rotor 53 can be relaxed if the same degree of fineness is achieved as compared with a conventional homogenizer or the like. , Means that the processing capacity can be improved. Further, if the stator 52 and the rotor 53 have a structure in which independent ring-shaped members are connected and integrated for each crushing tooth row 521, 531, the stator 52 and the rotor 53 are integrated.
Can be relatively easily and inexpensively increased in size to increase the throughput.

Therefore, according to the above-mentioned manufacturing method using the apparatus 1 for manufacturing the water-based emulsion dispersion liquid, the resin particles can be highly miniaturized without using the organic solvent, and the emulsifying machine 5 and others. It is possible to mass-produce high-quality water-based emulsion dispersions at a low cost, while being suitable for reducing equipment costs and operating costs, and at the same time being able to respond relatively easily to upsizing to increase the throughput. It will be possible.

The inventors of the present application conducted an experiment to confirm the above-mentioned actions and effects. The experiment was to produce a rosin sizing agent used as an internal additive for paper in the paper manufacturing process. The rosin sizing agent is an aqueous emulsion dispersion in which rosin, which is a thermoplastic natural resin collected from trees, is emulsified and dispersed in an emulsifier aqueous solution containing a surfactant. The physical properties of rosin used in this experiment are as shown in Table 1 below.

[0045]

[Table 1]

As the rotary emulsifier 5, Cavitron CD1010 (trade name) manufactured by Kuchitetsu Mining Co., Ltd. was used. The specifications of the Cavitron CD1010 are as follows. The stator 52, as shown in FIGS. 2 and 3,
The crushing tooth row 521 is formed in three rows concentrically,
The outer diameter of each crushing tooth row 521 is 35 to 68 mm, the number of raw material inserting grooves 523 in each crushing tooth row 521 is 24 to 72, and the groove width of the raw material inserting groove 523 in each crushing tooth row 521 is 2.
It is 0 to 0.6 mm. On the other hand, in the rotor 53, as shown in FIGS. 2 and 3, the crushing tooth rows 531 are concentrically formed in four rows, and each crushing tooth row 531 has an outer diameter of 35 to 74 mm. The number of raw material insertion grooves 533 in the crushing tooth row 531 is 12 to 72, and the groove width of the raw material insertion groove 533 in each crushing tooth row 531 is 3.0 to 0.6 mm. Further, as shown in FIG. 2, the axial gap S ₁ between the stator 52 and the rotor 53 is 0.6 mm, and the radial gap S ₂ (that is, the gap between the fracturing teeth 520 and 530).
Is 0.25 mm. The pipe diameter of the raw material supply port 54 and the raw material discharge port 56 is 12 mm. The rotor 5
No. 3 was operated at a rotation speed of 11,200 rpm (a peripheral speed of the outer circumference of the rotor 53 was about 40 m / s).

The cooling means 8 is a flexible metal pipe in which a cooling water tank having a capacity of 50 liters is flooded with industrial water at 20 ° C. at a rate of 3 liters / min and a raw material (emulsion dispersion liquid) is flown into the cooling water tank. What was sunk was used. The flexible metal pipe submerged in the cooling water tank has an inner diameter of 12 mm and a length of 3.5.
m.

The pressure control means 7 was set so that the internal pressure in the rotary emulsifying machine 5 (that is, Cavitron CD1010) was 4 kgf / cm ² G.

A rotary pump was used as the resin pump 23, and a mono pump was used as the emulsifier pump 33. The discharge flow rates of the respective pumps 23 and 33 were adjusted so that the mixing ratio of the thermoplastic resin and the emulsifier aqueous solution in the raw material flow in the mixing supply path 4 was 50:50 by weight, and the results are shown in Table 3 below. As shown, the amount of raw material supplied to the rotary emulsifier 5 is 120 kg / h, 200 kg.
/ H and 300 kg / h, the emulsified dispersion liquid was manufactured. The content of the surfactant in the aqueous emulsifier solution is 6% by weight. That is, the weight mixing ratio of the thermoplastic resin and the aqueous emulsifier solution in the raw material stream is 5
Since it is 0:50, the surfactant is mixed in the raw material stream at a ratio of 6% by weight of the thermoplastic resin.

The temperature just before the thermoplastic resin and the aqueous emulsifier solution are mixed by the mixing supply passage 4 is 180 ° C. in the case of the thermoplastic resin and 95 ° C. in the case of the aqueous emulsifier solution.
Then, initial heating and heating adjustment by the temperature control means 6 are performed so that the average temperature of the mixed raw material stream becomes 128 ° C.

Table 2 below summarizes the mixing ratio of rosin as the thermoplastic resin described above and the aqueous emulsifier solution, and the heating temperature.

[0052]

[Table 2]

Experiments were conducted under the above conditions, but for comparison,
Comparative Example 1 in which an emulsified dispersion was produced under the same conditions as in the above experiment except that the pressure control means 7 was opened to bring the internal pressure of the rotary emulsifier 5 to the atmospheric pressure state. In place of the rotary emulsifier 5, an existing Harrell homogenizer is used, and the other conditions are the same as those of the above experiment to produce an emulsion dispersion. Tried to manufacture. Comparative Example 2
The Haller homogenizer used in (1) had a gap between the stator and the rotor of 0.1 mm, which was narrower than that of the one embodiment.

In each of Example, Comparative Example 1 and Comparative Example 2, the raw material supply rate was 120 kg / h, 200 kg / h, 3
The production of rosin sizing agent was attempted for the three cases of 00 kg / h, and in each case, the resin fine particles in the emulsified dispersion liquid for which the production process was completed were subjected to a particle size analyzer by a light scattering method to obtain an average particle size (passage amount). The particle size corresponding to 50%) was measured. Table 3 below shows the measurement results.

[0055]

[Table 3]

As is clear from Table 3, according to the examples, the average particle size is 0.2 at any amount of the raw material supplied.
5 to 0.32 μm, it can be made into fine particles,
It was confirmed that a high-quality emulsified dispersion can be stably obtained. On the other hand, in the case of Comparative Example 1, water boils in the rotary emulsifier 5 and the emulsification treatment performance of the rotary emulsifier 5 cannot be sufficiently brought out, and the resin particles become very coarse. Oops. It can be seen how important the pressure control of the pressure control means 7 and the temperature control of the temperature control means 6 in the embodiment are. Further, in Comparative Example 2 as well, the average particle size of the resin particles was increased even though the high-precision homogenizer in which the gap between the stator and the rotor was smaller than that of the rotary emulsifier 5 used in the example was used. The diameter is about three times as coarse as that of the example, and it cannot be said that it is suitable for the production of rosin sizing agent in which it is desired to make the resin particles into fine particles having an average particle diameter of 0.5 μm or less. .

As can be seen from Comparative Example 2 described above, in the case where the average particle diameter of the thermoplastic resin may be reduced to about 1 μm, a homogenizer may be used instead of the rotary emulsifying machine 5. You may make it utilize the existing emulsifying machine. Also in this case, by optimizing the pressure control by the pressure control means 7 and the temperature control by the temperature control means 6 as in the above embodiment, it is possible to mass-produce the emulsion dispersion having a stable particle size at low cost. That is, the effect of the present invention can be obtained.

[0058]

According to the method and apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin of the present invention, the thermoplastic resin does not dissolve in an organic solvent, and is heated to reduce the viscosity to form an aqueous emulsifier solution. The mixture is supplied as a raw material to a rotary emulsifying machine, and the resin particles in the raw material are atomized into an emulsified state by a shearing action or the like in the rotary emulsifying machine, which causes an increase in apparatus cost and operating cost. No organic solvent recovery device is required. Moreover, the raw material to be supplied to the rotary emulsifier is maintained at an average temperature equal to or higher than the softening point of the contained thermoplastic resin, and the water in the raw material is kept in a state where the pressure is increased so as not to boil, etc. The properties of the raw material are controlled so that the emulsification process by the rotary emulsifier operates efficiently, and the occurrence of inconveniences such as cavitation due to boiling of water in the raw material in the rotary emulsifier is prevented. The emulsification processing performance of the emulsifying machine can be fully exerted. Then, as the rotary emulsifying machine, a crushing tooth row in which crushing teeth are arranged in an annular shape is concentrically arranged, and is fitted in an annular groove between adjacent crushing tooth rows of the stator. A rotary emulsifying machine having a configuration in which a crushing tooth row in which crushing teeth are annularly arranged is concentrically arranged corresponding to the arrangement of the crushing tooth rows on the stator and is driven to rotate, is used. In this case, due to the relatively rotating stator and a large number of crushing teeth of the rotor, a high shearing force acts on the resin particles and at the same time a high-frequency pressure fluctuation acts. Each of them works effectively for making the resin particles into fine particles, and it becomes possible to realize a sufficiently high degree of fine particles without making the gaps in which the raw material flows between the stator and the rotor fine. And this is
Compared with the conventional device, if you make the same degree of fine particles,
This means that the machining accuracy and the assembly accuracy of the stator and the rotor can be relaxed, and that the processing capacity can be improved. Further, if the stator and the rotor have a structure in which independent ring-shaped members are connected and integrated for each crushing tooth row, the stator and the rotor can be relatively easily and inexpensively increased in size and processed. The amount can be increased. Therefore, according to the manufacturing method and apparatus having the above-mentioned configuration, it is possible to highly miniaturize the resin particles without using an organic solvent, and at the same time, suitable for reducing equipment costs such as an emulsifier and operating costs, It is possible to respond relatively easily to large size to increase the throughput,
It is possible to mass-produce a high-quality aqueous emulsion dispersion at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin according to the present invention.

FIG. 2 is a vertical sectional view of a rotary emulsifying machine used in one embodiment of the present invention.

3 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Aqueous Emulsion Dispersion Manufacturing Device 2 Resin Supply Channel 3 Emulsifier Aqueous Solution Supply Channel 4 Mixing Supply Channel 5 Rotary Emulsifier 6 Temperature Control Means 7 Pressure Control Means 8 Cooling Means 9 Emulsion Dispersion Storage Tank 21 Thermoplastic Resin 22 Resin Tank 23 Resin Pump 24 Resin Flow Meter 31 Emulsifier Aqueous Solution 32 Emulsifier Tank 33 Emulsifier Pump 34 Emulsifier Flow Meter 51 Case Body 52 Stator 53 Rotor 61 Heat Medium Storage Tank 62 Heat Medium Pump 520,530 Fracturing Teeth 521,531 Fracturing Teeth Row

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokumitsu Kadota No. 2-1 Hirai, Hirai-cho, Nishitama-gun, Tokyo Inside Nittetsu Mining Co., Ltd.

Claims (6)

[Claims] 1. A thermoplastic resin stream obtained by heating a thermoplastic resin to a softening point or higher to reduce its viscosity to a predetermined level or less, and an emulsifier aqueous solution stream containing a surfactant and heated to an appropriate temperature below the boiling point of water. To form a raw material stream in which the thermoplastic resin and the aqueous emulsifier solution are mixed at a predetermined ratio, and the raw material stream is supplied to a rotary emulsifier to produce a resin in the raw material by shearing action in the rotary emulsifier. Thermoplastic to obtain an emulsified dispersion in which the resin particles contained are atomized to a predetermined particle size by cooling the raw material stream after the emulsification treatment with the rotary emulsifier to a predetermined temperature by atomizing the particles into an emulsified state. A method for producing an aqueous emulsion dispersion of a resin, wherein a raw material stream formed by the confluence of the thermoplastic resin stream and the emulsifier aqueous solution stream is rotated from the start of the confluence of the thermoplastic resin stream and the emulsifier aqueous solution stream. Type emulsification Until the time of exiting, the temperature is adjusted so that the average temperature is maintained at a predetermined temperature equal to or higher than the softening point of the thermoplastic resin, and pressure control is performed so that water in the raw material does not boil in the adjusted temperature environment. A method for producing an aqueous emulsion dispersion of a thermoplastic resin, which is characterized. 2. The rotary emulsifier comprises a stator having a structure in which crushing tooth rows in which crushing teeth are arranged in an annular shape are concentrically arranged on a disk-shaped substrate portion, and the stator is adjacent to the stator. The crushing tooth rows in which the crushing teeth that fit in the annular groove between the crushing tooth rows are arranged in an annular shape are arranged concentrically on the disk-shaped base plate portion corresponding to the arrangement of the crushing tooth rows on the stator. The rotator is driven to rotate, and the raw material insertion groove between adjacent crushing teeth in each crushing tooth row on the stator and the rotor is set to be smaller toward the tooth row on the outer peripheral side, and is rotated with the stator. The thermoplastic material according to claim 1, wherein the resin particles in the raw material are made finer to obtain an emulsified dispersion by flowing the raw material from the center toward the outer periphery between the child and the child. A method for producing an aqueous emulsion dispersion of a resin. 3. A resin supply path for supplying a constant flow rate of a thermoplastic resin whose viscosity is lowered below a predetermined value by heating the thermoplastic resin above its softening point, and an appropriate amount of water containing a surfactant and below the boiling point of water. An emulsifier aqueous solution supply path for supplying an emulsifier aqueous solution heated at a constant flow rate and a resin supply path and an emulsifier aqueous solution supply path are joined to form a raw material stream in which a thermoplastic resin and an emulsifier aqueous solution are mixed at a predetermined ratio. A mixing / supplying channel for generation / supply, a rotary emulsifier for atomizing resin particles in the raw material supplied from the mixing / supplying channel by a shearing action or the like into an emulsified dispersion state, the thermoplastic resin flow and the emulsifier aqueous solution flow. The raw material stream and the thermoplastic resin stream and the emulsifier water so that the average temperature of the raw material fluid is maintained at a predetermined temperature equal to or higher than the softening point of the thermoplastic resin from the start of the merging with the rotary emulsifier. Temperature control means for adjusting the temperature of the solution flow, from the start of merging the thermoplastic resin flow and the emulsifier aqueous solution flow so that water in the raw material flow does not boil at the temperature of the raw material flow set by the temperature control means. Production of an aqueous emulsion dispersion of a thermoplastic resin, comprising a pressure control means for adjusting the pressure of the raw material stream until the time of leaving the rotary emulsifier, and a cooling means for cooling the raw material stream leaving the rotary emulsifier. apparatus. 4. The rotary emulsifier comprises a stator having a structure in which crushing tooth rows in which crushing teeth are annularly arranged are concentrically arranged on a disk-shaped substrate portion, and the stator is adjacent to the stator. The crushing tooth rows in which the crushing teeth that fit in the annular groove between the crushing tooth rows are arranged in an annular shape are arranged concentrically on the disk-shaped base plate portion corresponding to the arrangement of the crushing tooth rows on the stator. The rotator is driven to rotate, and the raw material insertion groove between adjacent crushing teeth in each crushing tooth row on the stator and the rotor is set to be smaller toward the tooth row on the outer peripheral side, and is rotated with the stator. The thermoplastic resin according to claim 3, wherein the resin particles in the raw material are made finer to obtain an emulsified dispersion by flowing the raw material from the center toward the outer periphery between the child and the child. Equipment for producing an aqueous emulsion dispersion of resin. 5. The temperature control means comprises a jacket for flowing a heat medium to each of the resin supply path, the emulsifier aqueous solution supply path, the mixing supply path, and the rotary emulsifier, and the temperature adjustment and the flow rate of the heat medium. The apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin according to claim 3 or 4, wherein the temperature of the raw material stream is adjusted by adjustment. 6. The back pressure valve, which is provided after the cooling means and controls the pressure of a raw material flow in the rotary emulsifier, is used as the pressure control means.
6. An apparatus for producing an aqueous emulsion dispersion of a thermoplastic resin according to any one of items 1 to 5.