JP2013188938A - Method and device for high-pressure pulverizing molten resin lowered in viscosity by mixing carbon dioxide thereto - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for producing fine particles of molten resin by mixing carbon dioxide to the molten resin so as to lower viscosity and spraying the mixture into the atmosphere.SOLUTION: In a method for pulverizing molten resin by injecting molten resin continuously supplied under high pressure and high temperature and high pressure carbon dioxide to the atmosphere from the high pressure condition, when a fluid A and a fluid B are any of carbon dioxide and the molten resin, a multi-stage division flow passage type mixer is used as a mixer, which has a fluid A division part for evenly dividing the fluid A after the fluid A flows into the mixer, a fluid B division part for evenly dividing the fluid B after the fluid B flows into the mixer in the downstream side of the fluid A division part, a double tube type mixing part constituting a cylindrical double tube type mixer structure having the fluid A as the inner fluid and the fluid B as the outer fluid in the downstream side of the fluid B division part, and an individual contraction part for contracting an outlet of the double tube type mixing part in the downstream side of the double tube type mixing part. A pulverizing process of the resin and a product thereof can be provided.

Description

  The present invention relates to a high-pressure atomization method and apparatus for molten resin in which carbon dioxide is mixed to reduce viscosity, and more specifically, high-pressure carbon dioxide is supplied to the molten resin, and a high-pressure carbon dioxide mixer is provided therein. To reduce the viscosity by using a multi-stage divided flow channel mixer, and then spray directly from the high pressure to the atmosphere, or add the fluid for spraying before spraying The present invention relates to a molten resin high-pressure atomization method capable of producing resin fine particles by spraying as a fluid, a resin fine particle production method, and an apparatus therefor.

  Conventionally, most powder resin products manufactured by powder resin manufacturing technology are generally in the form of pellets or flakes, for example. The resin fine particle product of the form is generally expensive because of the processing cost. The resin fine particles are required to have a fine particle size and a narrow particle size distribution, and their uses range from a single resin member, a composite with an inorganic material, and a filler-containing resin to a general plastic molded product. For these resin fine particles, various high added values are strongly demanded for the multi-functionality of products, cost reduction of manufacturing methods, and greening.

  Such high-value-added products include, for example, powder paints, chemical toners, light diffusion sheets for liquid crystal displays, spacers, paints (emulsions), white pigments, highly dispersible cosmetics, microencapsulated products, porous products, Widespread use includes diagnostic test drugs (latex as particles for agglutination analysis), DDS (drug delivery system) microparticle preparations, microcapsules, and the like.

  Up to now, as a technology for producing powder resin, as a prior art, a gas phase method, a liquid phase method, a crystallization method, and a solid phase method have been proposed, and the characteristics and problems of each method are summarized. The results are shown in Table 1 below.

  In view of these characteristics and issues in conventional powder resin manufacturing technology, new manufacturing that can be applied to a wider range of resins, has a low environmental impact, and can manufacture resin particles at low cost. Process development is required.

  As a technology for producing fine particles using carbon dioxide, “particle production technology from a gas saturated solution” has attracted attention, and reported by Weidner et al. As PGSS (registered trademark) (Particle from Gas-Saturated Solutions) technology. [Patent Document 1, Non-Patent Document 1-2].

  Fields to which this technology is applied include, for example, pharmaceuticals [Non-Patent Documents 1 and 2], functional foods [Non-Patent Document 3], and resin atomization [Non-Patent Document 4]. Yes. An outline of the original apparatus for which this technique was proposed is shown in FIG.

  The apparatus will be described. In FIG. 1, the resin (3) is filled in an autoclave container (4) with a stirrer and heated and melted. Carbon dioxide (1) is pressurized and supplied to the autoclave by the booster pump (2) and dissolved in the molten resin.

  When carbon dioxide dissolves in the molten resin, the internal pressure of the autoclave decreases, so the carbon dioxide is charged and dissolved to saturation. Here, since only stirring is an element for promoting mass transfer, a long time is required for saturation dissolution. Thereafter, a valve (not shown) provided at the lower part of the autoclave is opened and ejected from the spray nozzle (5) into the atmosphere.

  At that time, the carbon dioxide pressure charging is continued. During the standby, a part of the sprayed resin fine particles is recovered from the tank lower part (6), and most of the resin fine particles are separated by the cyclone (7) and recovered from the cyclone lower part. A blower (8) is provided at the gas outlet of the cyclone. The features of PGSS (registered trademark) are organized as follows.

(1) Due to the dissolution of carbon dioxide, the resin has a low viscosity and can be sprayed.
(2) Depending on the conditions, melting point drops due to the dissolution of carbon dioxide, so products that are sensitive to temperature can be atomized at a low temperature.
(3) Since the viscosity reducing fluid is carbon dioxide, the fluid does not remain in the product after decompression.
(4) Since carbon dioxide dissolved in the resin is vaporized in the process of depressurization in the nozzle and also in the sprayed resin, atomization of the resin is promoted.
(5) The resin is cooled and solidified from a molten state to solid fine particles by the Joule-Thompson effect due to the reduced pressure of carbon dioxide.

  As shown in FIG. 1, in the existing method, it takes a long time to saturate and dissolve carbon dioxide in the resin, and since it is a batch process, continuous production cannot be performed. In recent years, Weidner et al. Have developed a fine particle production technique by constructing a pilot plant with a particle production amount of 50 kg / h shown in FIG. 2 [Non-patent Document 5].

  In the pilot plant of FIG. 2, the melted polymer is continuously supplied from the liquefaction dissolution tank (11) for melting and melting the resin by the gear pump (12), and the temperature is adjusted by the resin heater (13). Carbon dioxide (14) is discharged at a high pressure by a carbon dioxide pump (15), and the temperature is adjusted by a carbon dioxide heater (16).

  Both are mixed by a static mixer (17) and sprayed from a spray nozzle (18) to produce fine particles. The ejected fine particles are separated by the cyclone (19) and collected from the cyclone lower part (20). The gas outlet of the cyclone is sucked by a blower (21).

  This method enabled continuous production of fine particles. Weidner et al. Are investigating micronization of a polymer using polyethylene oxide (PEO: same as polyethylene glycol PEG) having a molecular weight of 6000, gas to polymer mass flow ratio (GTP), before spraying. Detailed investigations have been conducted on temperature, spray pressure, particle diameter, and particle shape [Non-patent Documents 5 and 6].

  In the above research and development of PGSS (registered trademark) technology, the molecular weight of the target polymer is up to about 6000, and when the molecular weight is higher than that, as shown in FIG. 3, polyethylene oxide PEO (polyethylene glycol PEG and The shape of the same fine particles is fibrous, and the shape of the particles cannot be maintained. Actually, development of a process for obtaining spherical fine particles is required even for a high molecular weight, that is, high viscosity molten resin, and the current Weidner et al. Method cannot satisfy such a requirement.

  The shape of the fine particles becomes fibrous, and the reason why the shape of the particles cannot be maintained is thought to be because the viscosity of the resin during spraying is not sufficiently lowered. This process is premised on operation in a one-phase state, and since the decrease in resin viscosity depends on the solubility of carbon dioxide, when carbon dioxide dissolves to the maximum solubility, the solubility decreases by adding more carbon dioxide. Does not occur.

  Therefore, it is important whether carbon dioxide is dissolved up to the maximum solubility. In that case, it is not an exaggeration to say that how homogeneously the low viscosity carbon dioxide is mixed into the high viscosity molten resin depends on the mixing performance of the mixer. One of the operating factors is thought to be a low spray flow rate.

European Patent No. 940079 (Patent No. 3510262)

Sencar-Bozic, P., Srcic, S., Knez, Z. and Kerc, J., "Improvement of nifedipine dissolution characteristics using supercritical CO2", Int. J. Pharm. 148 (1997) 123-130 Kerc, J., Srcic, S., Knez, Z. and Sencar-Bozic, P., "Micronization of drugs using supercritical carbon dioxide", Int. J. Pharm. 182 (1999) 33-39 Weidner, E., "high pressure micronization for food applications", J. Supercrit. Fluids 47 (2009) 556-565 Nalawade, S. P., Picchioni, F. and Janssen, L.P.B.M., "Batch production of micron size particles from poly (ethylene glycol) using supercritical CO2 as a processing solvent", Chem. Eng. Sci. 62 (2007) 1712-1720 Weidner, E., Petermann, M. and Knez, Z., "Multifunctional composites by high-pressure spray processes", Curr. Opin. Solid State Mat. Sci. 7 (2003) 385-390 Kappler, P., Leiner, W., Petermann, M. and Weidner, E., "Size and morphology of particles generated by spraying polymer-melts with carbon dioxide", Proceedings of the 6th Int. Symp. Supercrit. Fluids, 2003 , Versailles, pp.1891-1896

  In such a situation, the present inventors have used a polyethylene oxide PEO (same as polyethylene glycol PEG) having a molecular weight of 6000 or more which has not been achieved by the PGSS (registered trademark) technology developed by Weidner et al. With the goal of developing a molten resin atomization system, we have conducted extensive research. As a result, it was considered that the point of this technique is to efficiently and uniformly mix carbon dioxide into the molten resin continuously.

  Weidner et al. Used a static mixer to mix molten resin and carbon dioxide [Non-Patent Document 5], but thought that this static mixer had limitations in mixing performance, and further researched, the present invention It came to be completed. An object of the present invention is to provide a molten resin miniaturization method and apparatus capable of miniaturizing a molten resin by refining a high viscosity molten resin.

The present invention for solving the above-described problems comprises the following technical means.
(1) The molten resin that is continuously supplied at high pressure and the high-temperature and high-pressure carbon dioxide that is continuously supplied are mixed and dissolved by a mixer to reduce the viscosity of the molten resin and spray from high pressure conditions to atmospheric pressure. A method of atomizing molten resin by ejecting through a nozzle,
When fluid A and fluid B are either carbon dioxide or molten resin, after the fluid A flows into the mixer as a mixer, an equal pressure loss is generated and divided into a plurality of tubular channels. A fluid A splitting section;
Downstream of the fluid A dividing section, after the fluid B has flowed into the mixer, a fluid B dividing section that generates an equal pressure loss and equally divides the tubular flow path;
The number of divisions equal to the number of divisions of the fluid A division unit is provided downstream of the fluid B division unit, and the dual that constitutes a circular double-tube mixer structure in which the fluid A is an internal fluid and the fluid B is an external fluid A tube-type mixing section;
The downstream of the double tube type mixing unit is provided as many as the number of divisions of the fluid A dividing unit, and the individual contracted flow unit for contracting each double tube type mixing unit outlet,
A method for atomizing a molten resin, characterized by using a multistage divided flow channel mixer having the following.
(2) As a mixer, the above-mentioned double-tube type mixing unit of the multistage divided channel type mixer—the individual contraction unit and the collective contraction that contracts the entire channel disposed downstream thereof into one channel. A flow tube or a straight pipe-type staying portion having an arbitrary staying mixing time, a split kneading portion 1 that divides into a tubular flow channel disposed downstream thereof, and a split kneading portion 1 that has a different number of splits and is coaxial A multi-stage division having a divided kneading section 2 in which the circular flow path is arranged at a position where the outlet fluid of the divided kneading section 1 can be mixed with the adjacent fluid and outflow The method for atomizing a molten resin according to (1), wherein a flow channel mixer is used.
(3) As the mixer, the double-tube type mixing unit of the multi-stage divided flow channel type mixer—the individual flow-reducing unit, and the downstream portion thereof, the collective current-reducing unit for reducing the entire flow channel into one flow channel. The method for atomizing a molten resin according to (1), wherein a multistage divided flow channel mixer is used.
(4) As a mixer, the above-mentioned double tube type mixing section of the multistage divided flow channel type mixer—individual contraction section, and a multistage division having a straight pipe type retention section holding an arbitrary residence mixing time downstream thereof. The method for atomizing a molten resin according to (1), wherein a flow channel mixer is used.
(5) As a mixer, the above-mentioned double tube type mixing unit of the multi-stage divided channel type mixer—the individual contraction unit, and the collective contraction that contracts the entire channel disposed downstream thereof into one channel. The multistage divided flow channel type mixer having the divided kneading portion 1 that divides into a tubular flow channel is used downstream of the flow portion or the straight tube type retained portion having an arbitrary retained mixing time. Method for atomizing molten resin.
(6) As a mixer, downstream of the multistage divided flow channel mixer, the above-mentioned collective contraction part, straight pipe-type staying part, split kneading part 1 and / or split kneading part 2 are arbitrarily combined in any combination The method for atomizing a molten resin according to any one of (1) to (5), wherein a multistage divided flow path type mixer provided in a number of is used.
(7) As a mixer, at least one constituent member of the fluid A splitting unit, the double pipe mixing unit, the individual contraction unit, the split kneading unit 1, or the split kneading unit 2, or a flow path of a plurality of constituent members In the above (1), a multi-stage divided flow channel mixer is used, which is a micro flow channel having an inner diameter of 1 mm or less and is divided by a number of divisions in which the total pressure loss is 3 MPa or less, or 1 MPa or less. To (6). A method for atomizing a molten resin according to any one of (6) to (6).
(8) The molten resin fine particles according to any one of (1) to (7), wherein a housing for holding the mixer is provided on an outer periphery of the mixer so that the mixer can be used in a high temperature and high pressure environment. Method.
(9) The method for atomizing a molten resin according to any one of (1) to (8), wherein the fluid A is a molten resin and the fluid B is carbon dioxide in the multistage divided flow channel mixer.
(10) The molten resin atomization method according to any one of (1) to (9), wherein the fluid A is carbon dioxide and the fluid B is a molten resin in the multistage divided flow channel mixer.
(11) In the step before spraying the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed from the high pressure condition to the atmospheric pressure, the fluid for increasing the spray flow rate is additionally mixed, (1) to (10) The method for atomizing a molten resin according to any one of the above.
(12) Before the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed is sprayed from the high pressure condition to the atmospheric pressure, the fluid to be additionally mixed to increase the spray flow rate is carbon dioxide, nitrogen, helium, argon, or The method for atomizing a molten resin according to (11), wherein the method is neon.
(13) Using the molten resin atomization method according to any one of (1) to (12), the molten resin fine particles are produced by atomizing the molten resin. A method for producing resin fine particles.

Next, the present invention will be described in more detail.
The mixer used by this invention is comprised from the following means.
1) A multi-stage divided flow path type micro mixer that mixes fluid A and fluid B,
A fluid A dividing section for generating an equal pressure loss and dividing the fluid A into a plurality of circular channels after the fluid A flows into the mixer;
Downstream of the fluid A dividing section, after the fluid B has flowed into the mixer, a fluid B dividing section that generates an equal pressure loss and equally divides the tubular flow path;
The number of divisions equal to the number of divisions of the fluid A division unit is provided downstream of the fluid B division unit, and the dual that constitutes a circular double-tube mixer structure in which the fluid A is an internal fluid and the fluid B is an external fluid A tube-type mixing section;
The downstream of the double tube type mixing unit is provided as many as the number of divisions of the fluid A dividing unit, and the individual contracted flow unit for contracting each double tube type mixing unit outlet,
A multistage divided flow channel type mixer.

2) The above-mentioned double tube type mixing section of the multi-stage divided flow path type mixer—individual constricted flow section, and a collective contracted flow section or an arbitrary stay that contracts the entire flow path disposed downstream thereof into a single flow path. A straight kneading portion having a mixing time, a divided kneading portion 1 that divides into a tubular flow channel disposed downstream thereof, and a divided kneading portion 1 having a different number of divisions, and a coaxial circular flow channel And the divided kneading section 1 has a divided kneading section 2 in which a circular flow channel is arranged at a position where the outlet fluid can be mixed with the adjacent fluid and flow out. Split channel mixer.

3) The double pipe type mixing unit-individual contraction unit of the multistage divided channel type mixer, and an aggregated contraction unit for contracting the entire channel into one channel on the downstream side thereof 1) A multistage divided flow channel mixer according to claim 1.
4) Said double pipe type mixing part-individual contraction part of multistage division flow channel type mixer, and straight pipe type retention part holding arbitrary residence mixing time downstream thereof, as described in 1) above Multi-stage split channel mixer.

5) The above-mentioned double-tube type mixing section of the multi-stage divided flow path type mixer—individual contracted flow section, and a collective contracted flow section or an arbitrary stay for contracting the entire flow path disposed downstream thereof into one flow path The multistage divided flow channel mixer according to 1) above, which has a divided kneading unit 1 that divides into a tubular flow channel downstream of a straight pipe type retention unit having a mixing time.
6) In the downstream of the multistage divided flow channel type mixer, an arbitrary number of the above-mentioned collective flow-reducing section, straight pipe-type staying section, divided kneading section 1, or divided kneading section 2 are provided in any combination, The multistage divided flow channel mixer according to any one of 1) to 5).
7) In the flow path of at least one constituent member or a plurality of constituent members of the fluid A splitting section, the double pipe mixing section, the individual contraction section, the split kneading section 1 or the split kneading section 2, Is a micro flow channel of 1 mm or less, and is divided by the number of divisions in which the total pressure loss is 3 MPa or less, or 1 MPa or less.

  The present invention mixes and melts a molten resin that is continuously supplied at high pressure and high-temperature and high-pressure carbon dioxide that is also continuously supplied by a mixer to reduce the viscosity of the molten resin, and from high pressure conditions to atmospheric pressure. In this method, the molten resin is atomized by spraying through a spray nozzle, and when the fluid A and fluid B are either carbon dioxide or molten resin, the fluid A is used as the mixer. After flowing in, a uniform pressure loss is caused to equally divide the fluid A into a plurality of tubular channels, and after fluid B flows into the mixer downstream of the fluid A partition, the uniform pressure A fluid B dividing portion that causes a loss to be equally divided into circular flow paths, and the same number as the number of divisions of the fluid A dividing portion are provided downstream of the fluid B dividing portion. A circular double-pipe mixer serving as an external fluid The double pipe type mixing part that constitutes the structure, and the number of divisions of the fluid A dividing part are provided downstream of the double pipe type mixing part and the individual outlets of the double pipe type mixing part are contracted. It is characterized by using a multistage divided flow channel type mixer having a constricted flow part.

  In FIG. 4, the outline of the molten resin atomization apparatus by the continuous mixing of a carbon dioxide and molten resin is shown. In FIG. 4, resin pellets are put into a hopper (31), heated and melted by an extruder (32), and supplied to the next step. The number of revolutions of the extruder (32) is controlled so that the pressure P-1 at the outlet of the extruder (32) is constant at an arbitrary pressure, for example, several MPa. The molten resin supplied from the extruder (32) is quantitatively supplied to the high-pressure environment process by the gear pump (33). The molten resin line is provided with a rupture disk (34), a resin line pressure P-2, a stop valve SV-1, and a check valve CV-1. The resin line is, for example, a heat trace (not shown), It is preferable to maintain a heated and melted state.

  Carbon dioxide is quantitatively supplied from the carbon dioxide cylinder (35) through the cooler (36) to the high pressure environment process by the carbon dioxide pump (37). The carbon dioxide line may be a safety valve, but a back pressure valve PCV-1 is provided, and the pressure rises when the carbon dioxide supply is closed in SV-3, the pressure set by the back pressure valve PCV-1 or higher. Is preferably configured to return to the carbon dioxide pump (37) suction line.

  A carbon dioxide stable supply system is preferably used for the carbon dioxide line. This is a high-pressure carbon dioxide supply line, and a primary pressure control valve is provided upstream of the mixing section, and the set pressure of the primary pressure control valve is changed to the pressure of the mixing section in the line after the mixing section. By setting the pressure to a pressure larger than the pressure added, the intermittent supply of high-pressure carbon dioxide is suppressed and the supply flow rate is stabilized, that is, for example, the primary pressure control in the carbon dioxide line A valve PCV-2 is provided, and the pressure upstream of PCV-2 is maintained at a higher pressure than that of the mixer, preferably 2 MPa or more.

  It is also preferred to minimize the volume between PCV-2 and the mixer (39). Thereby, it is possible to suppress the occurrence of intermittent flow of carbon dioxide due to insufficient pressurization of the carbon dioxide line due to pressure fluctuations occurring downstream of the mixer.

  A pressure gauge P-4 and a flow meter F-1 are preferably provided downstream of the primary pressure control valve PCV-2 in the carbon dioxide line. Then, it heats to the temperature mixed with molten resin with a carbon dioxide heater (38). It is preferable to provide a stop valve SV-3 and a check valve CV-2 downstream of the heater.

  When the molten resin and carbon dioxide pass through the mixer (39), the carbon dioxide is dissolved in the molten resin, and the viscosity of the molten resin is reduced. In order to measure the viscosity reduction behavior, an orifice OF-1 and a differential pressure gauge ΔP-1 for measuring the differential pressure across the orifice are provided. The viscosity is calculated using the Hagen-Poiseuille equation shown in the following equation (1).

  The solubility of carbon dioxide in the molten resin depends on the mixing performance of the mixer. The mixer having high mixing performance required in this process is required to be capable of dissolving carbon dioxide to near saturation solubility in the residence time from the mixer to the differential pressure measuring unit. In actual operation, mixing is performed at a carbon dioxide addition rate equal to or lower than the saturation dissolution condition, and a condition for reliably maintaining a one-phase state is selected. It is important that the viscosity at that time is stable. That is, even if the operation is less than the saturation solubility, it is important that if the mixing performance is high, a viscosity reduction rate corresponding to the carbon dioxide addition rate can be obtained and a stable operation can be performed.

  Accordingly, the present invention, for example, mixes and dissolves a molten resin that is continuously supplied with high pressure and high-temperature and high-pressure carbon dioxide that is continuously supplied with a mixer, thereby reducing the viscosity of the molten resin, In the method of atomizing the molten resin by spraying from the pressure to the atmospheric pressure through a spray nozzle, a multistage divided flow channel type mixer is used as the mixer.

  Here, the multistage divided flow channel mixer used in the present invention will be described. First, an outline thereof is shown in FIG. The mixer shown in FIG. 5 is provided with a housing that can withstand pressure under high-temperature and high-pressure conditions on the outer periphery, and the mixer is contained inside the housing. When molten resin or carbon dioxide is used as either fluid A or fluid B, fluid A flows from the top, fluid B flows from the side, and fluid flows out from the bottom after mixing.

  In FIG. 6, the example of the component of a multistage division flow path type mixer is shown. In the present invention, as the mixer, the fluid A and the fluid B are mixed. After the fluid A flows into the mixer, the fluid is uniformly divided into a plurality of circular flow paths by causing an equal pressure loss. A divided part (part 1) and a fluid B divided part (part 2) that causes an equal pressure loss after the fluid B flows into the mixer downstream of the fluid A divided part and equally divides the tubular flow path. Side surface) and downstream of the fluid B dividing portion, the same number of divisions as the number of the fluid A dividing portion is provided, and a circular double-tube type mixer structure in which the fluid A is an internal fluid and the fluid B is an external fluid is provided. The double pipe type mixing section (parts 1 and 2) to be configured and the number of divisions of the fluid A dividing part are provided downstream of the double pipe type mixing part, and the outlets of the respective double pipe type mixing parts A multistage divided flow channel type mixer having an individual contracted portion (bottom surface of the component 2) for contracting the flow is used.

  The minimum configuration of the multistage divided flow channel mixer is composed of parts 1 and 2. FIG. 7 shows the details of the mixing state of the fluid A and fluid B in the double-tube mixing section and the individual contraction section. In the present invention, for example, a molten resin that is continuously supplied with high pressure and high-temperature and high-pressure carbon dioxide that is continuously supplied are mixed and dissolved by a mixer to reduce the viscosity of the molten resin, so that The molten resin is atomized by ejecting to atmospheric pressure through a spray nozzle.

  In the present invention, the double-tube type mixing section-individual contracted section (part 2) of the multistage divided channel mixer and the assembly for contracting the entire channel disposed downstream thereof into one channel. Divided kneading section 1 (divided into a constricted flow section (part 3-a) or a straight pipe-type stay section (part 3-b) having an arbitrary stay-mixing time and a circular flow path disposed downstream thereof The part 4) is different from the division kneading unit 1 in the number of divisions, does not have a coaxial circular channel, and the division kneading unit 1 outlet fluid can be mixed with the adjacent fluid and flow out. It is a preferred embodiment to use a multistage divided flow channel type mixer having a divided kneading section 2 (part 5) in which a circular flow channel is disposed.

  In the present invention, the double-tube type mixing unit-individual contraction unit (part 2) of the multistage divided channel type mixer, and the collective contraction that contracts the entire channel into one channel downstream thereof. The use of a multistage divided flow channel mixer having a flow section (part 3-a) is a preferred embodiment.

  Further, in the present invention, the above-mentioned double tube type mixing unit-individual contraction unit (part 2) of the multistage divided flow channel type mixer, and a straight pipe type retention unit (arbitrary residence mixing time downstream) It is a preferred embodiment to use a multi-stage split channel mixer with part 3-a).

  Further, in the present invention, as the mixer, the above-mentioned double tube type mixing section-individual contraction section (part 2) of the multistage divided flow path type mixer and the entire flow path disposed downstream thereof are combined into one flow. Divided kneading section 1 for dividing into a tubular flow channel downstream of a collective contraction section (part 3-a) to be contracted in a path or a straight pipe type retention section (part 3-b) having an arbitrary residence mixing time The use of a multistage divided flow channel mixer having (Part 4) is a preferred embodiment.

  Further, in the present invention, as the mixer, downstream of the multistage divided flow channel type mixer, the above-mentioned collective flow-reducing part (part 3-a), straight pipe type staying part (part 3-b), divided kneading part 1 It is a preferable embodiment to use (part 4) or a multistage divided flow channel mixer in which any number of divided kneading units 2 (parts 5) are provided in any combination.

  Moreover, in this invention, the fluid A division | segmentation part (part 1) using a multistage division | segmentation flow-path type mixer (part 1), a double pipe mixing part (part 2), an individual flow reduction part (part 2 bottom face), the division | segmentation kneading part 1 ( The flow path of at least one component of the component 4) or the divided kneading section 2 (component 5), or a flow path of a plurality of components, is a micro flow channel having a flow channel inner diameter of 1 mm or less, and has an overall pressure loss. A preferred embodiment is to use a multistage divided flow channel mixer that is divided by a division number of 3 MPa or less, preferably 1 MPa or less.

  In the present invention, a housing for holding the mixer is provided on the outer periphery so that the mixer can be used in a high temperature and high pressure environment. In the multistage divided flow channel mixer, fluid A and fluid B are carbon dioxide, In the multistage divided flow channel mixer, the fluid A is preferably carbon dioxide and the fluid B is preferably a molten resin.

  The multistage divided flow path type mixer used in the present invention is a structure constituted by a combination of components shown in FIGS. The basic structure of this structure will be described more specifically. In FIG. 5, the structure is divided equally into a plurality of tubular channels by causing an equal pressure loss after the fluid A flows into the mixer. And a fluid B dividing portion that is divided into a circular flow path by causing an equal pressure loss after the fluid B flows into the mixer downstream of the fluid A dividing portion. One layer [part 1] and a circular double-tube type provided downstream of the fluid B dividing portion by the same number as the number of divisions of the fluid A dividing portion, wherein fluid A is an internal fluid and fluid B is an external fluid The same number of divisions as the fluid A division part are provided downstream of the double pipe type mixing part and the double pipe type mixing part constituting the mixer structure, and each double pipe type mixing part outlet is contracted. And a second layer [part 2] composed of individual contracted portions.

  It is also possible to form a collective contraction part that contracts the entire flow path into one flow path, as shown in the part 3-a, downstream of the minimum basic configuration composed of the parts 1 and 2. is there. It is also possible to form a straight pipe-type staying section having an arbitrary staying and mixing time as shown in the part 3-b, downstream of the minimum basic structure composed of the parts 1 and 2.

  Split kneading to divide into a circular flow channel having a division number different from the division number of the individual constricted flow section, as shown in the part 4, downstream of the minimum basic configuration composed of the parts 1 and 2 As shown in the part 1 and the part 5, the number of divisions is different from that of the divided kneading part 1, and does not have a coaxial circular channel, and the divided kneading part 1 outlet fluid is mixed with the adjacent fluid. It is also possible to provide the divided kneading section 2 in which a circular channel is arranged at a position where it can flow out.

  Here, the part 3-a is installed upstream of the part 4, and the number of divisions of the flow path of the part 4 is not limited. However, when the part 3-b is installed upstream of the part 4, the individual compression is performed. The thing of the division number different from the division number of the flow path of a flow part is preferable.

  In addition, the parts indicated by parts 3-a, 3-b, parts 4, and 5 are provided in an arbitrary combination and in an arbitrary number downstream of the minimum basic configuration including parts 1 and 2 Is also possible. Although FIG. 1 shows an example in which the components 1, 2, 3-a, 4, 5, 4, 5 are combined in this order, other combinations of these components are 1, 2, 3-b, 4 , 5, 4, 5, or 1, 2, 4, 5, 4, 5.

  In this case, at least, a micro flow path having an inner diameter of 1 mm or less of the flow path of the fluid A dividing section, the double pipe mixing section, the individual contracted flow section, the divided kneading section 1 and the divided kneading section 2 is used. It is important to design the number of divisions of the flow path of the component parts so that the total pressure loss is 2 MPa or less, preferably 1 MPa or less. Since these depend on the conditions of the fluid flow rate and fluid viscosity in the fluid, it is important to design the microchannel according to the conditions to the appropriate number of divisions.

  From the Hagen-Poiseuille equation described above, the pressure loss can be calculated assuming the inner diameter and length of the microchannel, the volume flow rate of the fluid to be passed, and the viscosity. If the number of flow channel divisions is n, the cross-sectional area of the flow channel is n times and the flow velocity is 1 / n, so the pressure loss is 1 / n. Therefore, it is possible to determine the number of divisions in which the total pressure loss generated in each component is 3 MPa or less, preferably 1 MPa or less.

  For example, in the flow channel multistage split type mixer shown in FIG. 5, the pressure loss is 50 g / min mass flow rate and the fluid viscosity is 10,000 cP, and the flow channel has a total pressure loss of 0.9 MPa. The number of divisions is selected. In an actual experiment, since carbon dioxide dissolves and the viscosity decreases, the pressure loss decreases by the viscosity decrease rate.

  The present invention is particularly characterized in that a multistage divided flow channel mixer is used. The type of the molten resin applied to the mixer is not limited, and the multistage divided flow channel type is not limited. Any molten resin that can be applied to a mixer can be used.

  In the present invention, before the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed is sprayed from the high pressure condition to the atmospheric pressure using the multistage divided flow channel mixer, the fluid is additionally mixed in order to increase the spray flow rate. It is preferable to do. As shown in FIG. 4, before the molten resin whose viscosity has been reduced by mixing with carbon dioxide passes through the orifice OF-1 and is jetted as it is to the atmospheric pressure environment, the additional fluid for spraying (40) is mixed. The atomization can be promoted by increasing the spray flow rate.

  At this time, the pressure loss at the spray nozzle for mixing the additional fluid for spraying increases, so that the pre-spray pressure increases and the pressure in the system also increases. Therefore, it is preferable that the pressure control of the unit for reducing the viscosity by mixing the molten resin and carbon dioxide is controlled to a constant pressure by providing the primary pressure control valve PCV-3.

  In the present invention, before the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed is sprayed from the high pressure condition to the atmospheric pressure, the multistage divided flow path is added to the mixer for additionally mixing the fluid in order to increase the spray flow rate. The use of a mold mixer is a preferred embodiment. The mixer 41 in FIG. 4 may have a mixer structure such as a normal T-shaped joint, but is preferably a multistage divided flow channel mixer.

  In the present invention, before the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed is sprayed from the high pressure condition to the atmospheric pressure, the fluid to be additionally mixed is carbon dioxide, air, nitrogen, helium in order to increase the spray flow rate. Ar, argon or neon is preferred. In this case, the fluid that is first mixed with the molten resin needs to be dissolved in the molten resin to reduce the viscosity, and therefore needs to be carbon dioxide.

  On the other hand, the additional fluid for spraying may, of course, additionally supply carbon dioxide, but the meaning of the fluid added here may not be uniformly dissolved with the molten resin in which carbon dioxide is dissolved. Even if it becomes a two-phase flow just before spraying, the flow state of the two-phase flow is not an intermittent flow like a slag flow, any of a bubble flow, plug flow, two-layer flow, wave flow, annular flow, or spray flow It is important to have a uniform two-phase flow.

  Therefore, the additional fluid for spraying may be air, nitrogen, helium, argon, neon, or a mixture thereof. Moreover, the temperature and pressure before spraying can be controlled by controlling the addition flow rate and the addition temperature of the additional fluid for spraying. Thereby, the particle diameter and the form of the particles can be controlled by controlling the cooling temperature and surface tension of the droplets after spraying.

The present invention has the following effects.
(1) According to the present invention, resin fine particles produced by a gas phase method, a liquid phase method, a solid phase method, or the like can be continuously and stably produced using carbon dioxide having a low environmental load. It is.
(2) The process of the present invention can be developed not only as a molten resin but also as a process for atomizing various organic substances, and is expected to be applied and developed as a carbon dioxide stable supply system and a multistage divided flow channel mixer. Is done.
(3) It is possible to realize a method for atomizing a molten resin mixed with carbon dioxide to reduce the viscosity and a refined product of the molten resin.
(4) The particle diameter and particle shape of the fine particles of the molten resin can be controlled.
(5) An apparatus for atomizing molten resin can be provided.

A melt resin atomization apparatus (batch method) that saturates and dissolves carbon dioxide as an existing technology and sprays to atmospheric pressure is shown. A melt resin atomization apparatus (continuous method) that melts carbon dioxide as an existing technology and sprays it to atmospheric pressure is shown. The photograph of the microparticles | fine-particles of the molecular weights 6000 and 20000 of the manufactured polyethylene oxide (polyethylene glycol) atomized with the existing apparatus is shown. The molten resin atomization apparatus (continuous method) by the continuous mixing of the carbon dioxide and molten resin which concerns on this invention is shown. It is explanatory drawing which shows an example of a multistage division | segmentation flow-path type mixer. It is explanatory drawing which shows an example of the component of a multistage division | segmentation flow-path type mixer. It is explanatory drawing which shows the detail of the mixing state of the fluid in the double pipe mixing part-individual contraction part of a multistage division flow channel type mixer. The center collision type mixer of the existing mixer is shown. The relationship between a carbon dioxide addition rate and a viscosity reduction rate (viscosity ratio) is shown. The relationship between the flow rate of the additional fluid for spraying and the average particle size according to the spraying temperature (when the additional fluid for spraying is carbon dioxide) is shown. The photograph of the resin fine particle by the additional fluid flow for spraying and spraying temperature (when the additional fluid for spraying is carbon dioxide) is shown.

  Next, although the present invention will be described in detail based on examples of manufacturing mixers, apparatuses, and examples, the present invention is not limited to the following examples.

  Next, a production example of the multistage divided flow channel mixer of the present invention will be specifically described.

[Production example]
In this production example, an example in which the multistage divided flow channel mixer of the present invention is produced will be described. 5 to 7 show the details of the mixed state of the fluid in the multistage divided flow channel mixer of the present invention, its components, and the double-tube mixing section and the individual contraction section. The component parts 1 and 2 and the parts 3-a and 3-b shown in FIG. 6 are overlaid in this order, and further the parts 4 and / or the parts 5 are overlaid, so that the multistage divided flow shown in FIGS. A road mixer was assembled.

  In the multistage divided flow channel mixer, as shown in FIG. 5, fluid A, for example, high-pressure carbon dioxide fluid flows in from the upper part, and fluid B, for example, molten resin flows in from the side and is mixed from the lower part. After fluid flows out. Since the multistage divided flow channel mixer is installed in a housing having pressure resistance, the high pressure device only needs to have pressure resistance, and the multistage divided flow channel mixer can withstand pressure loss. What is necessary is just to have the intensity | strength to obtain.

  Here, the structure constituting the multi-stage split channel mixer shown in FIG. 5 is a strong structure that can be manufactured only by machining and can withstand machining, and is a conventional micromixer. It is not a delicate structure composed of a fine structure. As a result, for example, even if the pressure loss of the fluid is 3 MPa, there is no damage to the structure, but normally, the number of divisions when the above components are stacked is designed so that the pressure loss is 1 MPa or less. .

  Among the components of the multistage divided flow channel mixer, the component 1 is divided equally into a plurality of circular flow channels by causing a uniform pressure loss after the fluid A, for example, high-pressure carbon dioxide fluid flows in. The fluid A divided portion was formed as a fluid A divided portion. That is, specifically, the component 1 is formed so that 21 circular pipes are connected to the bottom surface, and the 21 circular pipes have inner diameters such that the fluid A is equally divided. The lengths were made to be exactly equal.

  The component 2 has a plurality of groove-like flow paths from the side surface, and has a structure in which the fluid B, for example, molten resin flows in and spreads around the entire side surface. For the component 2, the fluid B dividing portion is formed by arranging the circular pipe so that the flow paths of the 12 circular pipes merge toward the center space inside the groove-shaped flow path. Divided part. The twelve circular tubes were produced so that the inner diameter and length thereof were exactly equal so that the fluid B was equally divided.

  The fluid 2 was divided into equal parts, and the component 2 was applied in a container shape so as to flow into the center of the component 2. A circular recess having the same number as the number of divisions of the fluid A was formed on the container-like bottom of the part 2. The circular pipe is disposed with the end face of the circular pipe through which the fluid B uniformly flows into the dent and the fluid A flows out into the center of the dent, thereby being the same as the fluid A division number. Several circular double-tube mixers were formed to form a double-tube mixer.

  Each of the double-tube type mixing units is provided with the same number of channels as the number of divided channels of the fluid A dividing unit on the bottom surface of the component 2 disposed downstream of the double-tube type mixing unit. An individual flow-reducing part for reducing the flow of the outlet was formed, and the minimum basic configuration of the multi-stage divided flow channel mixer was composed of part 1 and part 2.

  Further, downstream of the minimum basic configuration composed of the parts 1 and 2, a collective contraction part for contracting the entire flow path into one flow path as shown in the part 3-a is formed. A straight pipe-type staying section having an arbitrary staying and mixing time as shown in the part 3-b was formed downstream of the minimum basic structure composed of the parts 1 and 2.

  A divided mixture that is divided into a circular flow channel having a division number different from the division number of the flow path of the individual constricted flow section, as shown in the component 4, downstream of the minimum basic configuration constituted by the component 1 and the component 2. As shown in the smelting unit 1 and the part 5, the divided kneading unit 1 and the number of divisions of the flow path are different, do not have a coaxial circular channel, and the divided kneading unit 1 outlet fluid is adjacent to the fluid. A multi-stage division in which a divided kneading section 2 in which circular flow channels are arranged at positions where they can be mixed and flowed out is provided, and these parts 4 and 5 can be provided as needed. A flow channel mixer was manufactured.

[Apparatus and Examples]
A fine particle production technique (PGSS) by ejecting a gas saturated solution is already known, and a technique for atomizing a molten resin has been studied. The principle is to obtain fine particles by dissolving carbon dioxide in a molten resin to lower the viscosity and spraying it toward atmospheric pressure. Therefore, in this embodiment, (1) a multistage divided flow channel mixer is applied to the mixing of the molten resin and carbon dioxide to improve mixing performance, and carbon dioxide is continuously mixed to a saturated state quickly and stably. (2) Mixing an additional fluid for spraying immediately before spraying to increase the jet flow velocity and promoting atomization.

  A high-pressure atomization apparatus for molten resin in which low viscosity is obtained by mixing carbon dioxide, that is, high-temperature and high-pressure carbon dioxide, for example, subcritical or supercritical carbon dioxide will be described with reference to the apparatus shown in FIG. To do. The resin pellets were put into a hopper (31), heated and melted with an extruder (32), and supplied to the next step.

  The number of revolutions of the extruder (32) was controlled so that the pressure P-1 at the outlet of the extruder (32) became an arbitrary pressure, for example, a few MPa. The molten resin supplied from the extruder (32) was quantitatively supplied to the high pressure environment process by the gear pump (33). The molten resin line is provided with a rupture disk (34), a resin line pressure P-2, a stop valve SV-1, and a check valve CV-1, and the resin line is heated and melted by a heat trace (not shown). Retained.

  Carbon dioxide was quantitatively supplied from the carbon dioxide cylinder (35) through the cooler (36) to the high-pressure environment process by the carbon dioxide pump (37). The carbon dioxide line is provided with a back pressure valve PCV-1, and a pressure higher than the pressure set by the back pressure valve PCV-1 with respect to the pressure rise that occurs when the supply of carbon dioxide is closed in SV-3 is a carbon dioxide pump (37 ) It was configured to return to the suction line.

  A carbon dioxide stable supply system was used for the carbon dioxide line. This is because the primary pressure control valve PCV-2 is provided in the carbon dioxide line to minimize the volume between the PCV-2 and the mixer (39) and is higher than the pressure of the mixer (39), preferably 2 MPa. The above high pressure condition was maintained. As a result, the generation of an intermittent flow of carbon dioxide due to insufficient pressurization of the carbon dioxide line due to pressure fluctuations occurring downstream of the mixer was suppressed.

  A pressure gauge P-4 and a flow meter F-1 were provided downstream of the primary pressure control valve PCV-2 in the carbon dioxide line. Then, it heated to the temperature mixed with molten resin with the carbon dioxide heater (38). A stop valve SV-3 and a check valve CV-2 were provided downstream of the heater.

  By passing the molten resin and carbon dioxide through the mixer (39), the carbon dioxide was dissolved in the molten resin to reduce the viscosity of the molten resin. In order to measure the viscosity lowering behavior, an orifice OF-1 and a differential pressure gauge ΔP-1 for measuring the differential pressure across the orifice were provided. The viscosity was calculated using the Hagen-Poiseuille equation shown in the following equation (1).

  In the multistage divided flow channel mixer used in this example, the solubility of carbon dioxide in the molten resin depends on the mixing performance of the mixer. The mixer used in this process can dissolve carbon dioxide to near saturation solubility in the residence time from the mixer to the differential pressure measurement unit. In actual operation, mixing was performed at a carbon dioxide addition rate equal to or lower than the saturation dissolution condition, and a condition for reliably maintaining a one-phase state was selected. That is, even when the operation was less than the saturation solubility, a viscosity reduction rate corresponding to the carbon dioxide addition rate was obtained, and a stable operation was possible.

  FIG. 8 shows a center collision type mixer used as a comparative example. This mixer has a high mixing performance compared with the T-shaped mixer and the static mixer that have been used conventionally [Reference: K. Mae, et al., J. Chem. Eng. Japan, 40. (12), 1101-1107 (2007)].

  As shown in FIG. 8, molten resin flows from the upper part and carbon dioxide flows from the lower part. The carbon dioxide is evenly branched into four flow paths after flowing into the mixer and collides with the molten resin at the central part of the mixer. The internal flow path is a thin single flow path of 1 to 2 mm. A needle that can adjust the flow path gap of the center collision portion is inserted in the flow path of the molten resin, and the flow path gap can be adjusted while observing the mixed state. In the experiment, the pressure loss was too large, so the needle was removed and used.

  Viscosity reduction rate from initial viscosity by using polyethylene glycol (PEG 20000) having a molecular weight of 20000 in the molten resin and mixing and dissolving carbon dioxide using the above-mentioned center impingement mixer and the above-mentioned multistage divided flow channel mixer. I investigated. The effect of the mixer structure on the decrease in the viscosity of the molten resin was examined by changing the addition rate of carbon dioxide with respect to a constant resin mass flow rate (30 g / min).

  If the performance of the mixer is good, it is considered that carbon dioxide is better dissolved in the molten resin and the viscosity is lowered. In the case of poor mixing, it is considered that the rate of decrease in viscosity decreases and the variation in measured differential pressure increases when a two-phase state is reached. The temperature was constant at 110 ° C. and the pressure was 15 MPa.

  FIG. 9 shows the viscosity reduction rate (viscosity ratio) depending on the carbon dioxide addition rate. Viscosity decreasing behavior was shown with an initial viscosity at 1.0% addition of carbon dioxide being 1.0. When the carbon dioxide addition rate increases regardless of the mixer, the viscosity ratio generally decreases. Compared with the center impingement type mixer, the viscosity reduction rate was larger in the multistage divided flow channel type mixer.

  The fluctuation range of the measured differential pressure indicated by the error bar also increased at the carbon dioxide addition rate of 17, 20 and 24% in the central collision type mixer, and was considered to be in a two-phase state. The multistage divided flow channel mixer did not change even at a carbon dioxide addition rate of 30%, and thus was considered to be uniformly dissolved.

  Carbon dioxide supplied for viscosity reduction of the molten resin is about 10 to 30% with respect to the mass flow rate of the molten resin, and more than that in the operating conditions of the existing apparatus design conditions of 300 ° C. and 30 MPa. It became a gas-liquid two-phase flow without dissolving. Therefore, it was considered preferable to operate at a carbon dioxide addition rate lower than that. However, PEG having a molecular weight of 20000 did not atomize even when sprayed at atmospheric pressure with only dissolved carbon dioxide.

  Therefore, in FIG. 4, before the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed is sprayed from the high pressure condition to the atmospheric pressure using the multistage divided flow channel mixer, the fluid is used to increase the spray flow rate. Additional mixing. As shown in FIG. 4, before the molten resin, the viscosity of which was reduced by mixing carbon dioxide, was jetted through the orifice OF-1 to the atmospheric environment as it was, the additional fluid for spraying (40) was mixed.

  Thereby, the spray flow rate was increased to promote atomization. At this time, since the pressure loss at the spray nozzle for mixing the additional fluid for spraying increased, the pre-spray pressure increased, and the pressure in the system also increased. Therefore, the pressure control of the unit for reducing the viscosity by mixing the molten resin and carbon dioxide was controlled to a constant pressure by providing the primary pressure control valve PCV-3.

  As a mixer that additionally mixes fluid in order to increase the spray flow rate before spraying a mixed fluid in which molten resin and carbon dioxide are uniformly mixed from high pressure conditions to atmospheric pressure, mixing such as a normal T-shaped joint However, it has been found that the multistage divided flow channel mixer is preferable.

  Before spraying a mixed fluid that is a homogeneous mixture of molten resin and carbon dioxide from high pressure conditions to atmospheric pressure, additional fluids to mix the fluid to increase the spray flow rate are carbon dioxide, air, nitrogen, helium, argon Alternatively, neon is used, but the fluid that is initially mixed with the molten resin needs to be carbon dioxide because it must be dissolved in the molten resin to lower the viscosity.

  On the other hand, the additional fluid for spraying may not be uniformly dissolved with the molten resin in which carbon dioxide is dissolved. Even if it becomes a two-phase flow just before spraying, the flow state of the two-phase flow is not an intermittent flow like a slag flow, any of a bubble flow, plug flow, two-layer flow, wave flow, annular flow, or spray flow It is important to have a uniform two-phase flow.

  It has been found that the additional atomizing fluid may be air, nitrogen, helium, argon, neon, or a mixture thereof. In addition, by controlling the addition flow rate and addition temperature of the additional fluid for spraying, the temperature and pressure before spraying are controlled to control the cooling temperature and surface tension of the droplets after spraying, and the particle size and particle size. It was found that the form of can be controlled.

  Here, the results when carbon dioxide is supplied as the additional fluid for spraying are shown in FIGS. As an additional fluid for spraying, a carbon dioxide pump was separately supplied immediately before the spraying section. Carbon dioxide to be supplied to the spraying part was sufficiently heated and supplied, and the pressure of the spraying part was controlled by the resin temperature after mixing and the carbon dioxide supply flow rate.

  The conditions of the spraying experiment were PEG-20000 as the molten resin, the flow rate was 11 to 12 g / min, the mixing part control pressure was 18 MPa, and the carbon dioxide addition amount in the mixing part was the value of the differential pressure gauge immediately after the mixer. The addition rate was set to 20 to 21 wt% with small variations. Regarding carbon dioxide added for spraying, while changing the flow rate in the range of 3 to 12.5 kg / h and changing the temperature just before spraying in the range of 100 to 160 ° C., the particle size and particle shape of the generated particles I investigated.

  FIG. 10 shows the relationship between the set temperature of the sprayed carbon dioxide and the average particle diameter (X50) of the generated particles for each sprayed carbon dioxide flow rate. When the spray carbon dioxide flow rate is 3 to 4 kg / h, 5.5 to 6 kg / h, a sampling cup is placed under the spray gun, a sample is collected, and after removing +600 μm adhering to the sample cup, A particle size of −600 μm was evaluated (weight ratios of −600 μm were 79 to 93 wt% and 26 to 50 wt%, respectively).

  When the spray part carbon dioxide flow rate was 11.5 to 11.6 kg / h, a cyclone was connected to the spray container, and a sample was collected (approximately 25 wt% of the spray amount). Therefore, it is difficult to directly compare, but as shown in FIG. 10, it was considered that the larger the carbon dioxide flow rate in the spray portion, the more the fine particles tend to be generated.

  FIG. 11 shows an SEM image of each sample. From these images, the smaller the carbon dioxide flow rate in the spray part, the easier it is to produce rounded particles. When the carbon dioxide flow rate in the spray part is 3-4 kg / h, almost spherical particles are produced. It was confirmed that Moreover, it has also confirmed that the rounded particle | grains are easy to produce | generate when the preset temperature of the carbon dioxide in a spray part is high. From these facts, it has been found that spherical fine powder can be produced by atomizing the molten resin by optimizing or optimizing the flow rate and temperature of the sprayed carbon dioxide.

  As described in detail above, the present invention relates to a high pressure atomization method and apparatus for molten resin mixed with carbon dioxide to reduce viscosity, and was produced by a pulverization method or a chemical method according to the present invention. It became feasible to produce resin fine particles using carbon dioxide with low environmental impact. According to the present invention, development as a process for atomizing not only molten resin but also various organic substances is possible, and application development such as a stable carbon dioxide supply system and a multistage divided flow channel mixer is expected. According to the present invention, it is possible to provide a method for atomizing a molten resin mixed with carbon dioxide to reduce the viscosity and to provide a refined product of the molten resin, and to control the refined form of fine particles of the molten resin. It is possible to produce a spherical fine powder by adjusting the flow rate and temperature of the sprayed carbon dioxide. INDUSTRIAL APPLICABILITY The present invention is useful as an apparatus for atomizing molten resin and also providing a technique for atomizing molten resin that makes it possible to produce a fine powder product of molten resin.

(Explanation of symbols in FIGS. 1 and 2)
(1) Carbon dioxide (2) Booster pump (3) Resin (4) Autoclave container (5) Spray nozzle (6) Lower tank (7) Cyclone (8) Blower (11) Liquefaction dissolution tank (12) Gear pump (13) Resin heater (14) Carbon dioxide (CO ₂ )
(15) Carbon dioxide pump (16) Carbon dioxide heater (17) Static mixer (18) Spray nozzle (19) Cyclone (20) Cyclone lower part (21) Blower

Claims (13)

The molten resin that is continuously supplied at high pressure and the high-temperature and high-pressure carbon dioxide that is continuously supplied are mixed and dissolved by a mixer to reduce the viscosity of the molten resin, and from the high-pressure condition to atmospheric pressure via a spray nozzle. A method of atomizing the molten resin by jetting,
When fluid A and fluid B are either carbon dioxide or molten resin, after the fluid A flows into the mixer as a mixer, an equal pressure loss is generated and divided into a plurality of tubular channels. A fluid A splitting section;
Downstream of the fluid A dividing section, after the fluid B has flowed into the mixer, a fluid B dividing section that generates an equal pressure loss and equally divides the tubular flow path;
The number of divisions equal to the number of divisions of the fluid A division unit is provided downstream of the fluid B division unit, and the dual that constitutes a circular double-tube mixer structure in which the fluid A is an internal fluid and the fluid B is an external fluid A tube-type mixing section;
The downstream of the double tube type mixing unit is provided as many as the number of divisions of the fluid A dividing unit, and the individual contracted flow unit for contracting each double tube type mixing unit outlet,
A method for atomizing a molten resin, characterized by using a multistage divided flow channel mixer having the following.   As the mixer, the double-tube type mixing unit of the multi-stage divided flow channel type mixer—individual contracted flow unit, and a collective contracted flow unit that contracts the entire flow channel disposed downstream thereof into a single flow channel. A straight pipe-type staying section having an arbitrary staying mixing time, a split kneading section 1 that divides into a tubular flow channel disposed downstream thereof, and the split kneading section 1 has a different number of splits, and is coaxially circular. A multistage split flow channel type having a split kneading section 2 that does not have a tubular flow path, and has a circular flow path disposed at a position where the outlet fluid of the split kneading section 1 can mix and flow out with the adjacent fluid. The method for atomizing a molten resin according to claim 1, wherein a mixer is used.   As a mixer, the above-mentioned double tube type mixing unit of the multi-stage divided flow channel type mixer—the individual flow-reducing unit, and the multi-stage division having an aggregated flow-reducing unit downstream of the entire flow channel into a single flow channel The method for atomizing a molten resin according to claim 1, wherein a flow channel mixer is used.   As a mixer, a multistage divided flow path type multi-stage divided flow path type mixer having the above-mentioned double pipe type mixing section-individual contracted flow section and a straight pipe-type staying section holding an arbitrary stay mixing time downstream thereof The method for atomizing a molten resin according to claim 1, wherein a mixer is used.   As the mixer, the double-tube type mixing unit of the multi-stage divided channel type mixer—the individual contraction unit, and the collective contraction unit that contracts the entire channel disposed downstream thereof into one channel. 2. The molten resin fine particles according to claim 1, wherein a multistage divided flow channel mixer having a divided kneading portion 1 that divides into a tubular flow channel is used downstream of a straight pipe type retained portion having an arbitrary stay mixing time. Method.   As the mixer, downstream of the multistage divided flow channel type mixer, any number of the above-mentioned collective contraction part, straight pipe type staying part, divided kneading part 1 and / or divided kneading part 2 are provided in any combination. The method for atomizing a molten resin according to any one of claims 1 to 5, wherein a multistage divided flow channel mixer is used.   As a mixer, at least one constituent member of the fluid A splitting unit, the double pipe mixing unit, the individual flow reduction unit, the split kneading unit 1, or the split kneading unit 2, or a flow path of a plurality of constituent members, The multi-stage divided flow channel type mixer that is a micro flow channel having a channel inner diameter of 1 mm or less and is divided by a number of divisions in which the total pressure loss is 3 MPa or less, or 1 MPa or less is used. A method for atomizing a molten resin according to claim 1.   The method for atomizing a molten resin according to any one of claims 1 to 7, wherein a housing for holding the mixer is provided on an outer periphery of the mixer so that the mixer can be used in a high temperature and high pressure environment.   The method for atomizing a molten resin according to any one of claims 1 to 8, wherein the fluid A is a molten resin and the fluid B is carbon dioxide in the multistage divided flow channel mixer.   The method for atomizing a molten resin according to any one of claims 1 to 9, wherein the fluid A is carbon dioxide and the fluid B is a molten resin in the multistage divided flow channel mixer.   The fluid for increasing the spraying flow rate is additionally mixed in the step before spraying the mixed fluid in which the molten resin and carbon dioxide are uniformly mixed from the high pressure condition to the atmospheric pressure. Method for atomizing molten resin.   Prior to spraying a mixed fluid in which molten resin and carbon dioxide are uniformly mixed from high-pressure conditions to atmospheric pressure, the fluid to be additionally mixed to increase the spray flow rate is carbon dioxide, nitrogen, helium, argon, or neon. The method for atomizing a molten resin according to claim 11.   Production of resin fine particles, characterized in that fine particles of the molten resin are produced by atomizing the molten resin by using the molten resin atomization method according to any one of claims 1 to 12. Method.