JP6632286B2 - Method for lowering thermal expansion coefficient of resin molding - Google Patents

Description

  The present invention relates to a method for reducing the coefficient of thermal expansion of a resin molded article containing inorganic particles.

  Various resin materials have been used as supports or protective films for electronic circuit boards and the like. However, the resin material generally has a coefficient of thermal expansion one to two orders of magnitude higher than that of a conductive material composed of an inorganic material. Therefore, various problems such as warpage of the base material, separation from the conductive material and the like, dimensional change, and the like occur in the heating step. Then, a method of reducing the thermal expansion coefficient of the resin molded article by adding various inorganic fine particles has been proposed.

  However, the non-uniform dispersion of the inorganic particles causes deterioration of various physical properties of the obtained resin molded article. In particular, when fine inorganic particles are used, the particles are likely to aggregate, and such aggregates have been regarded as one of the causes of uneven dispersion. Therefore, various methods have been proposed for dispersing and uniformly dispersing these aggregates in the dispersion step.

  Patent Literature 1 discloses a method in which a medium such as a bead mill is introduced into a dispersion, and crushing or crushing is performed using friction energy between media particles. As the medium, zirconia beads or the like are used. However, in a bead mill, there is a limit to the viscosity that can be effectively dispersed, and productivity is reduced when a large amount of a solvent (dispersion medium) is added in order to adjust the dispersion to a low viscosity. There are also problems in terms of quality and work, such as mixing of media fragments in the dispersion step and separation of the dispersion from the medium after the dispersion treatment.

  Patent Literature 2 discloses a dispersion method using a planetary mixer, a homomixer, a dissolver, or the like. The homomixer and the dissolver can cope with a dispersion having a higher viscosity than the above-mentioned bead mill, but the dispersion often stays in the stirring tank. A planetary stirring disperser such as a planetary mixer can process high-viscosity dispersions, but the clearance between the stirring blades is wide, effective shear energy is not applied, and a sufficiently uniform dispersion can be obtained. There may not be.

  In the paint and ink industries, three-roll dispersion has been attempted, and is widely used as a technique for obtaining a high-viscosity uniform dispersion. However, since the three rolls are dispersed in an open system, when a volatile dispersion medium is used, there are problems such as an increase in the viscosity of the mixed solution and the incorporation of airborne foreign substances. In order to achieve high dispersion, it is necessary to narrow the clearance between rolls.However, in a large-sized machine, etc., since a slight difference in roll angle greatly affects dispersibility, a stable and good dispersion state is obtained. It was difficult to maintain.

JP-A-2002-105211 JP 2006-249276 A

  Therefore, an object of the present invention is to provide a method capable of improving the dispersibility of inorganic particles and effectively reducing the coefficient of thermal expansion of a resin molded product containing inorganic particles.

As a result of intensive studies in view of the above problems, the present inventors have found that, by adding inorganic particles to a mixed solution containing a resin component and a solvent, and passing through a process using a pressure disperser, the dispersion of the inorganic particles The present inventors have found that the properties are improved, and the coefficient of thermal expansion of the obtained inorganic particle-containing resin molded article is reduced, and have reached the present invention. That is, the method for reducing the coefficient of thermal expansion of the resin molded article of the present invention is a step of dispersing inorganic particles using a pressure dispersing machine in a mixed solution containing a solvent-soluble resin and a solvent, and dispersing the inorganic particles. A step of applying and drying the mixed solution.
The pressure dispersing machine preferably includes a pressure intensifier and a flow path of a mixed liquid having a constricted portion.
Preferably, the flow path has a first constriction and a second constriction.
Further, a turbulence generator may be arranged between the first constriction and the second constriction.
Further, a wall orthogonal to the longitudinal direction of the flow path of the mixed liquid is provided on the downstream side of the second constriction, and a wall is provided between the downstream end of the longitudinal flow path of the second constriction and the wall. Alternatively, a flow path radially extending radially outward from the downstream end may be formed.

Further, the method for reducing the coefficient of thermal expansion of a resin molded article containing inorganic particles according to the present invention is characterized in that the method includes a step of pressurizing and spraying a slurry containing the inorganic particles, resin and solvent.
In the above step, it is preferable that the slurry is pressurized, passed through the first constricted portion arranged in the flow path, and then jetted.
Further, it is more preferable that after the slurry is jetted, the slurry is further passed through a second constricted portion arranged in the flow path.
The slurry that has passed through the longitudinal flow path of the second constriction is disposed downstream of the second constriction and has a diameter from the downstream end of the longitudinal flow path between a wall perpendicular to the flow path and the wall. It can flow radially outward in the direction.

  In the method for reducing the coefficient of thermal expansion of a resin molded product of the present invention, the resin is preferably a polyimide copolymer.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal expansion coefficient of the resin molding containing an inorganic particle can be reduced effectively.

It is a schematic diagram of a pressure dispersing machine used for a dispersion process in the present invention. FIG. 1 is a schematic sectional view of a pressure dispersing machine used in an embodiment of the present invention. FIG. 6 is an exploded perspective view of a pressure disperser used in another embodiment of the present invention. FIG. 6 is a schematic cross-sectional view of a main part of a dispersion unit of a pressure dispersion machine used in another embodiment of the present invention.

In the method for reducing the coefficient of thermal expansion of the inorganic particle-containing resin molded body of the present invention, the resin molded body is a step of dispersing the inorganic particles using a pressure dispersing machine in a mixed solution containing a solvent-soluble resin and a solvent. It is characterized by being obtained through Further, in the method for reducing the coefficient of thermal expansion of an inorganic particle-containing resin molded article of the present invention, the resin molded article is obtained through a step of pressing and jetting a slurry containing inorganic particles, a resin and a solvent. .
Hereinafter, the inorganic particle-containing resin molded product of one embodiment of the present invention will be described in detail.

In one embodiment of the present invention, the inorganic particle-containing resin molded body is obtained through (1) a mixing step, (2) a dispersion step, and (3) a molding step.
Hereinafter, details of each step will be described.

(1) Mixing Step In the present invention, it is preferable that the resin, the solvent, and the inorganic particles are previously mixed before the dispersion step. The mixing method is not particularly limited, and a normal mixing method (slurry) or the like is used. For example, stirring-type mixing using a paddle, an anchor blade or the like can be mentioned. In addition, before the dispersion step described below, mixing can be performed using a planetary mixer, a dissolver, a homomixer, or the like.
The resin, the inorganic particles and the solvent which are components of the slurry of the present invention will be described below.

(A) Resin The resin material used in the present invention is not particularly limited as long as it is a resin that is soluble in a solvent, and an optimum resin material can be used according to the required characteristics of the application field of the resin molded article. Specific resin materials include polyethylene resin, polypropylene resin, polyester resin, epoxy resin, phenoxy resin, polyimide resin, polyetherimide resin, polyesterimide resin, polyamide resin, polyamideimide resin, vinyl chloride resin, acrylic resin, and phenol. Resins, polycarbonate resins, polyethersulfone resins, polyvinyl alcohol resins, and the like. Among them, epoxy resin, polyimide resin and the like are preferably used. These resins may be used alone or in combination of two or more.

(B) Inorganic particles The inorganic particles used in the present invention are not particularly limited, and metal particles, ceramic particles and the like are used. Optimum inorganic particles can be used according to the required characteristics of the application field of the resin molded article. However, ceramic particles are preferable in order to more effectively reduce the coefficient of thermal expansion of the resin molded body. Specific examples of the ceramic particles include titanium oxide, aluminum oxide, zirconium oxide, silicon oxide, silicon carbide, silicon nitride, and aluminum nitride. Among them, titanium oxide, aluminum oxide, silicon oxide and the like are preferable.
These inorganic particles may be used alone or in combination of two or more.
The average particle diameter of the inorganic particles used in the present invention is preferably in the range of 0.01 to 100 μm.
By setting the average particle diameter of the inorganic particles to be used in the above range, the coefficient of thermal expansion of the obtained resin molded product can be more effectively reduced.

  The content of the inorganic particles is set according to the required coefficient of thermal expansion of the resin molded body and other physical properties. Specifically, it is preferable to add the inorganic particles 5 to 150 to the resin 100 in a mass ratio. In the present invention, uniform dispersion can be achieved by using a pressure disperser described below, even if the amount of inorganic particles added is increased. Therefore, the coefficient of thermal expansion of the resin molded article can be effectively reduced while maintaining the productivity and other physical property values.

(C) Solvent The solvent used in the present invention is not particularly limited, and a solvent capable of dissolving the resin to be used is selected. Specific solvents include, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butyl alcohol, allyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, diethylene glycol monoethyl ether, and tripropylene glycol. Glycol or derivatives thereof such as dimethyl ether, polypropylene glycol monoethyl ether, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, glycerol or derivatives thereof such as glycerol, glycerol monoethyl ether, glycerol monoallyl ether, tetrahydrofuran, dioxane, etc. Ethers, methyl ethyl Tones, ketones such as methyl isobutyl ketone, decane, decene, methylnaphthalene, decalin, kerosene, diphenylmethane, hydrocarbons such as toluene, dimethylbenzene, ethylbenzene, diethylbenzene, propylbenzene, cyclohexane, chlorobenzene, dichlorobenzene, bromobenzene, Halogenated hydrocarbons such as chlorodiphenyl and chlorodiphenylmethane, ethyl benzoate, octyl benzoate, dioctyl phthalate, trioctyl trimellitate, dibutyl sebacate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) ) Ester compounds such as dodecyl acrylate, lactones such as γ-butyrolactone, water and the like. These solvents may be used alone or in combination of two or more. The amount of the solvent to be added is not particularly limited, and is appropriately set in consideration of the viscosity of the obtained mixture.

(2) Dispersion Step In the method for reducing the coefficient of thermal expansion of a resin molded article of the present invention, inorganic particles are dispersed in a mixed solution containing a solvent-soluble resin and a solvent using a pressure disperser (high-pressure disperser). It is characterized by going through a process. Here, the pressure disperser is a disperser having a pressure intensifier (pump) and a configuration capable of applying a pressure to a liquid.
FIG. 1 shows a schematic view of a pressure dispersing machine used in the dispersing step in the present invention. The pressure disperser 100 includes a supply container 110, a pump 120, a dispersion unit 200, and a collection container 130. A mixed solution containing the solvent-soluble resin, the solvent, and the inorganic particles is supplied to the supply container 110, is sent to the dispersion unit 200 in a pressurized state by the pump 120, and is collected in the collection container 130 through the dispersion process. You. By using such a pressure disperser, a slurry in which inorganic particles are uniformly dispersed can be obtained. In a normal pressure disperser, a pressure of several hundred MPa or less is applied.
Further, the method for reducing the coefficient of thermal expansion of a resin molded article of the present invention is characterized in that the method includes a step of pressing and spraying a slurry containing inorganic particles, a resin and a solvent. By using the slurry as a high-pressure jet, the inorganic particles can be uniformly dispersed. For this reason, the inorganic particles are uniformly dispersed in the resin molded body produced from the obtained slurry, and the thermal expansion is higher than that of the resin molded body produced from the slurry prepared by the conventional dispersion method at the same composition ratio. The rate drops.

FIG. 2 is a schematic sectional view of a pressure disperser used in one embodiment of the present invention. The pressure disperser 10 includes a slurry input port 11, a cylindrical slurry flow path 12 extending perpendicular to the slurry input port 11, a constricted portion 13 connected to the slurry flow path 12, and a slurry recovery port connected to the constricted portion 13. It has 14. In addition, a plunger 15 is provided in the slurry flow channel 12, and the plunger 15 reciprocates to pressurize the slurry.
When a predetermined amount of slurry is introduced into the slurry flow channel 12 from the slurry introduction port 11, the plunger 15 moves to the right in the drawing, and pressurizes the slurry. The pressurized slurry is sent into the constricted portion 13 and becomes a high-speed flow, and the pressure rapidly decreases near the recovery port 14. At this time, shearing force due to friction with the wall surface, collision between droplets, cavitation, and the like occur, and the aggregation of the inorganic particles in the slurry is broken. Therefore, in the slurry recovered through the dispersion step of the present invention, the deagglomerated inorganic particles are uniformly dispersed. By applying and drying such a slurry, the inorganic particles are uniformly dispersed, and a resin molded body having a low coefficient of thermal expansion can be obtained.

(3) Forming Step If necessary, a solvent is added to the obtained slurry to adjust the viscosity to form a coating solution, which is applied to a support such as a release film or a SUS belt, and dried. Thereafter, the molded body is peeled from the support, and the obtained film can be used as a support for an electronic circuit board or a protective film. In addition, the above-mentioned coating solution is applied to a substrate, dried, and laminated with a conductive layer or the like of an electronic component or the like, so that it can be used as various laminated bodies.

  FIG. 3 is an exploded perspective view of a dispersion unit 200 of a pressure dispersion machine used in another embodiment of the present invention. FIG. 4 is a schematic vertical sectional view of a main part of the dispersion unit 200. As shown in these drawings, the dispersion unit 200 includes a filter module 210, a nozzle module 220, a diffusion module 230, a miniaturization module 240, and an internal pressure adjustment module 250.

  As shown in FIG. 3, the modules 210 to 250 are manufactured, for example, as metal products. These modules 210 to 250 are connected to each other by passing bolts and nuts (not shown) through the holes.

  As shown in FIGS. 3 and 4, cylindrical holes 211, 221, 231, and 241 that extend along the longitudinal direction of the dispersion unit 200 are formed near the center of each of the modules 210 to 240. In the miniaturization module 240, the hole 241 is formed in an L shape. More specifically, on the upstream side of the miniaturization module 240, the hole 241 extends along the longitudinal direction of the dispersion unit 200, and on the downstream side, extends in the transverse direction. In the dispersing unit 200, the holes 211, 221, 231, and 241 form a flow channel 260 through which the mixed liquid flows. A ring-shaped seal member 202 is attached near the ends of the holes 211, 221, 231, and 241. Thereby, the liquid tightness of the flow path 260 in the connection part of each module 210 to 240 is ensured. The mixture flows in the order of the hole 211 → the hole 221 → the hole 231 → the hole 241.

A filter 212 is provided in the hole 211 of the filter module 210.
The upstream end of the nozzle module 220 is connected to the downstream end of the filter module 210. As shown in FIG. 4, the nozzle module 220 is formed such that the inner diameter of the hole 211 gradually decreases from upstream to downstream. That is, in the nozzle module 220, the width of the flow channel 260 is maximum near the upstream end, and is minimum near the downstream end. Therefore, in the vicinity of the downstream end of the nozzle module 220, the width of the flow path 260 is narrower than its nearest downstream (near the upstream end of the diffusion module 230) or its most upstream (near the upstream end of the nozzle module 220). A part 222 is formed.

The upstream end of the diffusion module 230 is connected to the downstream end of the nozzle module 220. The inner diameter of the hole 231 of the diffusion module 230 is larger than the inner diameter of the first constricted portion 222 of the nozzle module 220. That is, the width of the flow channel 260 in the diffusion module 230 is wider than the width of the flow channel 260 in the first constricted portion 222.
The diffusion module 230 has a configuration in which the upstream block 232 and the downstream block 233 are combined.

  The upstream end of the miniaturization module 240 is connected to the downstream end of the diffusion module 230. The valve 242, the valve seat 243, and the ring 244 are inserted into the hole 241 of the miniaturization module 240. The valve seat 243 is arranged on the upstream side of the hole 241. The valve seat 243 has therein a hole 245 extending in the longitudinal direction of the dispersion unit 200. In a portion of the hole 241 where the valve seat 243 is located, the flow channel 260 is formed in the hole 245. The downstream end surface 246 of the valve seat 243 is orthogonal to the longitudinal direction of the distribution unit 200.

  Downstream of the valve seat 243, a valve 242 is installed. The upstream end surface 247 of the valve 242 is orthogonal to the longitudinal direction of the dispersion unit 200. That is, the downstream end surface 246 of the valve seat 243 and the upstream end surface 247 of the valve 242 are parallel to each other. The position of the valve 242 in the longitudinal direction can be adjusted by a screw 251 of the internal pressure adjustment module 250 described later.

  Downstream of the hole 245 of the valve seat 243, the flow channel 260 is formed between the downstream end surface 246 of the valve seat 243 and the upstream end surface 247 of the valve 242. Usually, the distance between both end faces is set to be small. Therefore, between the downstream end surface 246 of the valve seat 243 and the upstream end surface 247 of the valve 242, a constricted portion 248 in which the width of the flow path 260 is reduced is formed. The constriction portion 248 radially extends radially outward from the hole 245 of the valve seat 243. For this reason, the flow path 260 in the constricted portion 248 extends in a direction orthogonal to the flow path 260 in the hole 245. Therefore, when the vicinity of the constriction part 248 is viewed in a vertical cross section, the flow path 260 immediately upstream of the entrance to the constriction part 248 and the flow path 260 in the constriction part 248 have a right angle relationship. In the miniaturization module 240, the width of the constricted portion 248 can be adjusted by adjusting the position of the valve 242 in the longitudinal direction. Here, the hole 245 in the valve seat 243 and the constricted portion 248 constitute a second constricted portion.

  A ring 244 is attached to the outside of the valve 242 and the valve seat 243. Specifically, the valve 242 and the valve seat 243 are inserted inside the ring 244. The inner peripheral surface 249 of the ring 244 is located near the outer peripheral surfaces of the valve 242 and the valve seat 243 with a predetermined distance therebetween. Therefore, the inner peripheral surface 249 of the ring 244 is located near the outlet of the constriction 248. Thus, the inner peripheral surface 249 forms a wall against which the mixed liquid coming out of the constricted portion 248 collides. When the stenotic portion 248 and the inner peripheral surface 249 are viewed in a longitudinal section, the direction of the flow path 260 in the stenotic portion 248 is perpendicular to the inner peripheral surface 249. As described above, there is a gap between the inner peripheral surface 249 of the ring 244 and the outer peripheral surfaces of the valve 242 and the valve seat 243. Downstream of the constriction 248, this gap forms the flow channel 260. Further, in the miniaturization module 240, the downstream end of the hole 241 is open below the miniaturization module 240. For this reason, near the downstream end of the hole 241, the flow channel 260 extends in a direction perpendicular to the longitudinal direction of the dispersion unit 200.

  The upstream end of the internal pressure adjusting module 250 is connected to the downstream end of the miniaturization module 240. The screw 251 is inserted into the hole 252 of the internal pressure adjustment module 250. A spring 253 is extrapolated to the screw 251. Further, a pressing member 254 is attached to a tip of the screw 251. Then, the screw 251 presses the valve 242 of the miniaturization module 240 via the pressing member 254. A handle 255 is attached to the proximal end of the screw 251. When the handle 255 is turned, the screw 251 rotates. Thereby, the position of the screw 251 in the longitudinal direction is adjusted. Then, by adjusting the position of the screw 251, the position of the valve 242 of the miniaturization module 240 is adjusted. Thus, the width of the second constriction 248 is adjusted. As described above, in the dispersion unit 200, the valve 242, the valve seat 243, and the internal pressure adjusting module 250 constitute a hydraulic pressure adjusting mechanism 270 for adjusting the hydraulic pressure of the flow channel 260.

1) Operation of High-Pressure Disperser As shown in FIG. 1, the liquid mixture charged into the supply container 110 is first supplied to the dispersion unit 200 by the pump 120. As shown in FIG. 4, since the first constricted portion 222 and the second constricted portions 245 and 248 are formed on the flow channel 260, the fluid pressure in the flow channel 260 increases. The mixed liquid that has entered the dispersion unit 200 first passes through the filter 212 of the filter module 210. As a result, large contaminants are removed from the mixture.

  Next, the mixed solution passes through the first constricted portion 222 of the nozzle module 220. In the first constricted portion 222, the width of the flow channel 260 is narrow, so that the fluid pressure in the flow channel is high. In that state, the mixture enters the hole 231 of the diffusion module 230. The volume of the internal space of the hole 231 is larger than the volume of the first constricted part 222. For this reason, the mixed liquid having an increased liquid pressure in the first constriction portion 222 rapidly diffuses in the hole 231 when entering the hole 231. Thereby, dispersoids such as inorganic particles are uniformly dispersed in the dispersion medium (resin solution). As described above, in the dispersion unit 200, the diffusion unit that disperses the dispersoid in the dispersion medium is configured in the hole 231 of the diffusion module 230.

  Thereafter, the mixture enters the constriction 248 from the hole 231 of the diffusion module 230 through the hole 245 of the valve seat 243. Here, the mixture flows from the hole 245 radially outward with the direction of flow changed by 90 °. Since the width of the flow channel 260 is also narrow at the narrowed portion 248, the fluid pressure in the flow channel is high. In that state, the mixture flows into the ring 244. The mixed liquid whose liquid pressure has been increased in the constriction portion 248 is discharged at a high speed in the circumferential direction of the constriction portion 248 after leaving the constriction portion 248. As described above, the inner peripheral surface 249 of the ring 244 is located near the downstream of the constriction 248. Therefore, the mixed liquid collides with the inner peripheral surface 249 of the ring 244 at a high speed. Thereby, the inorganic particles are further miniaturized and more uniformly dispersed in the mixed liquid. Finally, the liquid mixture that has exited the miniaturization module 240 is collected in the collection container 130 shown in FIG.

2) How to Use High-Pressure Disperser The pump 120 is operated with the valve 242 closed, that is, the flow path 260 closed, and the pump output is set so that the pump pressure becomes the first pressure. This first pressure is preferably 50 to 100 MPa.

  Next, the valve 242 is opened to release the hydraulic pressure in the flow channel 260. At this time, the opening degree of the valve 242 is adjusted so that the pump pressure becomes the second pressure. The second pressure is preferably 20 to 90 MPa. Further, the difference between the first pressure and the second pressure is preferably 5 to 30 MPa. Further, the second pressure is preferably 0.8 to 0.95 times the first pressure.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In Examples, unless otherwise specified, “%” and “part” indicate “% by mass” and “part by mass”.
A mixed solution was prepared by adding the resin, the inorganic particles, and the solvent shown in Table 1 at the compounding ratios shown in Table 1, and stirring with an anchor blade.

  Next, the obtained liquid mixture was treated with the apparatus shown in Table 2.

  However, in the first embodiment, the dispersion unit 200 of the pressure disperser 100 includes the filter module 210, the miniaturization module 240, and the internal pressure adjustment module 250. In the pressure disperser 100 according to the second embodiment, the dispersion unit 200 includes the filter module 210, the nozzle module 220, the diffusion module 230, the miniaturization module 240, and the internal pressure adjustment module 250. Table 3 shows the operating conditions of Example 1 and Example 2.

  A film having a thickness of 20 μm was prepared using the obtained liquid mixture, and the coefficient of thermal expansion was measured using a thermomechanical analyzer (TMA). Specifically, the measurement was performed at a load of 5 g and a temperature rising rate of 10 ° C./min, and the coefficient of thermal expansion at 50 ° C. to 200 ° C. was calculated. Table 4 shows the results.

  As shown in Table 4, in the resin molded article of Example 1 obtained from the mixed liquid dispersed using the pressure dispersing machine 100, the comparative example obtained from the mixed liquid dispersed using three rolls was used. The coefficient of thermal expansion was lower than that of the resin molded product No. 1. In addition, the resin molded product of Example 2 obtained from the mixed liquid that passed through the first constriction and the second constriction was more thermally expanded than Example 1 obtained from the liquid mixture that passed only the second constriction. The rate was found to decrease further.

100 pressure disperser 110 supply container 120 pump 130 collection container 200 dispersion unit 202 sealing member 210 filter Module 211: Hole 212: Filter 220: Nozzle module 221: Hole 222: First constriction 230: Diffusion module 231: Hole 232: Upstream block 233: Downstream block 235: Edge 240: Miniaturization module 241: Hole 242: Valve 243: Valve seat 244: Ring 245: Hole 246: Downstream end surface 247 ・ ・ ・ Upstream end surface 248 ・ ・ ・ Constriction 249 ・ ・ ・ Inner peripheral surface 250 ・ ・ ・ ・ ・ ・ Internal pressure adjusting module 251 ・ ・ ・ Screw 252 ・ ・ ・ Hole 53 ... spring 254 ... pressing member 255 ... handle 260 ... passage 270 ... hydraulic adjustment mechanism

Claims (3)

Dispersing the inorganic particles in a liquid mixture containing a solvent-soluble resin and a solvent by using a pressure disperser having a flow path of the liquid mixture having a first constriction and a second constriction; Having a step of applying and drying a mixed liquid in which inorganic particles are dispersed,
The flow path between the first constriction and the second constriction extends linearly;
A diffusion portion is disposed between the first constriction portion and the second constriction portion ;
On the downstream side of the second constriction, a wall orthogonal to the longitudinal direction of the flow path of the mixed solution is provided, and between the downstream end of the longitudinal flow path of the second constriction and the wall, the thermal expansion coefficient decreases method of the resin molded body, characterized in Rukoto flow path extending radially outward in the radial direction from the downstream end is formed.   The method according to claim 1, wherein the pressure disperser includes a pressure intensifier. The method according to claim 1 or 2, wherein the resin is a polyimide copolymer.