JP7071235B2 - Porous molded body and its manufacturing method - Google Patents

Description

The present invention relates to a porous molded product and a method for producing the same.

A porous molded body made of resin powder is a molded body obtained by heat-treating resin powder in a porous state in which voids remain at the interface where particles overlap, and is a filter, a sound absorbing material, and an impregnating material. , Coating materials, medical-related parts, information-related parts, electronic parts, etc. Since the polyarylene sulfide resin has high mechanical strength and is excellent in heat resistance and chemical resistance, the resin powder containing the polyarylene sulfide resin fine particles is used in a high temperature environment or an environment in contact with an acidic solution. It is expected that a porous molded product that can be formed can be formed. As one of the porous molded products using polyarylene sulfide resin fine particles, a porous molded product using polyphenylene sulfide particles having an average particle size of 150 μm or more is known (Patent Document 1).

Japanese Unexamined Patent Publication No. 02-298527

However, the porous molded body made of polyphenylene sulfide particles having an average particle size of 150 μm or more may not have sufficient initial strength because the adhesion between the resin fine particles is low. The adhesion between the resin fine particles has a great influence on the performance and strength of the porous molded product during use. That is, if the adhesion between the resin fine particles is poor, the pores may become large or the porous molded body may be destroyed during use. When press molding is performed at a high temperature of over 300 ° C. or a high pressure of over 1500 MPa in order to improve the adhesion between the resin fine particles, the strength is increased but the porosity is lowered. If the porosity decreases and goes out of the predetermined range, the characteristics such as dielectric properties, air permeability and permeability may not be sufficient.

An object of the present invention is to provide a porous molded product having excellent strength and low dielectric constant and a method for producing the same.

The present invention relates to the following.
[1] A polyarylene sulfide resin powder having an average particle size of 5 μm or more and 100 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less is used, and the porosity is 20%. A porous molded body having a content of 60% or more and 60% or less.
[2] The porous molded body according to [1], wherein the average circularity measured by the dynamic image analysis method of the polyarylene sulfide resin powder is 0.70 or more and 1.00 or less.
[3] The melt viscosity of the polyarylene sulfide resin powder measured at a cylinder temperature 30 ° C. higher than the melting point Tm1 measured by a differential scanning calorimeter and a shear rate of 1200 sec ^-1 is 25 Pa · s or more and 5000 Pa · s or less. The porous molded body according to [1] or [2].
[4] Described in any one of [1] to [3], wherein the ratio of the maximum particle size to the average particle size (maximum particle size / average particle size) of the polyarylene sulfide resin powder is 6.5 or less. Porous molded body.
[5] The porous molded product according to any one of [1] to [4], wherein the relative permittivity at a frequency of 1 MHz is 1.0 or more and 2.5 or less.
[6] The method for producing a porous molded body according to any one of [1] to [5], wherein the average particle size is 5 μm or more and 100 μm or less, and the melting point Tm1 measured by a differential scanning calorimeter is 250. A powder material containing a polyarylene sulfate resin powder having a temperature of ° C. or higher and 300 ° C. or lower is press-molded at a temperature of (melting point Tm1-15) ° C. or higher (melting point Tm1 + 15) ° C. or lower and a pressure of 0.1 MPa or higher and 30 MPa or lower. A manufacturing method having a step of performing.

According to the present invention, it is possible to provide a porous molded body having excellent strength and low dielectric constant and a method for producing the same.

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications as long as the effects of the present invention are not impaired.

[Porous molded body]
In the process of research, the present inventor set the average particle size of the polyarylene sulfide resin powder and the melting point Tm1 measured by the differential scanning calorimeter within a predetermined range to ensure the adhesion between the polyarylene sulfide resin fine particles. It has been found that a porous molded body having a low dielectric constant can be obtained, and the present invention has been completed.

(Resin powder)
The porous molded body according to the present embodiment is a porous molded body formed by using polyarylene sulfide resin powder (hereinafter, also referred to as “resin powder”) composed of polyarylene sulfide resin fine particles. be. In the present specification, the term "fine particles" refers to particles having an average particle size of about 0.1 μm to 1000 μm, and the “average particle size” is a volume measured by a laser diffraction / scattering type particle size distribution measurement method. It means the standard arithmetic mean particle size. The average particle size can be measured, for example, by using a laser diffraction / scattering type particle size distribution measuring device LA-920 manufactured by HORIBA, Ltd.

The polyarylene sulfide resin is a resin having a repeating unit represented by the following general formula (I).
-(Ar-S) -... (I)
(However, Ar indicates an arylene group.)

The arylene group is not particularly limited, but for example, a p-phenylene group, an m-phenylene group, an o-phenylene group, a substituted phenylene group, a p, p'-diphenylene sulphon group, a p, p'-biphenylene group, p, Examples thereof include a p'-diphenylene ether group, a p, p'-diphenylene carbonyl group, and a naphthalene group. The polyarylene sulfide resin A can be a copolymer containing different types of repeating units in addition to homopolymers using the same repeating units among the repeating units represented by the above general formula (I).

As the homopolymer, one having a p-phenylene group as an arylene group and having a p-phenylene sulfide group as a repeating unit is preferable. This is because homopolymers having a p-phenylene sulfide group as a repeating unit have extremely high heat resistance, and exhibit high strength, high rigidity, and high dimensional stability in a wide temperature range. By using such a homopolymer, a molded product having very excellent physical properties can be obtained.

As the copolymer, a combination of two or more different allylene sulfide groups among the above allylene sulfide groups including the allylene group can be used. Among these, a combination containing a p-phenylene sulfide group and an m-phenylene sulfide group is preferable from the viewpoint of obtaining a molded product having high physical properties such as heat resistance, moldability and mechanical properties. A polymer containing 70 mol% or more of p-phenylene sulfide group is more preferable, and a polymer containing 80 mol% or more is further preferable. The polyarylene sulfide resin having a phenylene sulfide group is a polyphenylene sulfide resin (PPS resin).

The polyarylene sulfide resin is generally known to have a molecular structure that is substantially linear and does not have a branched or crosslinked structure, or a structure that has a branched or crosslinked structure, depending on the production method. Is valid for any of these types.

The method for producing the polyarylene sulfide resin is not particularly limited, and the polyarylene sulfide resin can be produced by a conventionally known production method. For example, it can be produced by synthesizing a low molecular weight polyarylene sulfide resin and then polymerizing it at a high temperature in the presence of a known polymerization aid to increase the molecular weight.

Various fibrous, powdery, plate-like inorganic and organic fillers can be blended in the polyarylene sulfide resin. As the fibrous filler, glass fiber, milled glass fiber, carbon fiber, asbestos fiber, silica fiber, silica / alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, Examples thereof include silicate fibers such as wollastonite, magnesium sulfate fibers, aluminum borate fibers, and inorganic fibrous substances such as metal fibrous materials such as stainless steel, aluminum, titanium, copper and brass. A particularly typical fibrous filler is glass fiber. In addition, high melting point organic fibrous substances such as polyamide, fluororesin, polyester resin, and acrylic resin can also be used.
Examples of the powder / granular filler include carbonates such as carbon black, graphite, silica, quartz powder, glass beads, glass balloons, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and wollastonite. , Iron oxide, Titanium oxide, Zinc oxide, Antimonite trioxide, Metal oxides such as alumina, Calcium carbonate, Metal carbonates such as magnesium carbonate, Sulfates of metals such as calcium sulfate and barium sulfate, Other ferrites, carbonized Examples thereof include silicon, silicon nitride, boron nitride, and various metal powders.
Examples of the plate-like filler include mica, glass flakes, talc, and various metal foils.
These inorganic and organic fillers can be used alone or in combination of two or more.

The content of the filler can be 5 to 200 parts by mass with respect to 100 parts by mass of the polyarylene sulfide resin. Further, the polyarylene sulfide resin may contain additives such as an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, a pigment, and a crystal nucleating agent as other components.

The melting point Tm1 measured by the differential scanning calorimetry of the polyarylene sulfide resin powder is 250 ° C. or higher and 300 ° C. or lower, preferably 255 ° C. or higher and 300 ° C. or lower, and more preferably 260 ° C. or higher and 300 ° C. or lower. .. By setting the melting point Tm1 to 250 ° C. or higher and 300 ° C. or lower, the heat resistance of the porous molded body can be enhanced, and when the average particle size described later is satisfied, in addition to high strength, excellent dielectric properties and aeration. It can be a porous molded body having properties and permeability.
The melting point Tm1 is the temperature of the peak top at the endothermic peak of 1stRUN observed when heating (1stRUN) from room temperature at a heating rate of 10 ° C./min by a method based on JIS K-7121 (1999). do.

The polyarylene sulfide resin powder has a cylinder temperature 30 ° C. higher than the melting point Tm1 measured by a differential scanning calorimeter and a melt viscosity measured at a shear rate of 1200 sec ^-1 of 25 Pa · s or more and 5000 Pa · s or less. It is more preferably 25 Pa · s or more and 1000 Pa · s or less. By setting the melt viscosity of the polyarylene sulfide resin powder within the above range, a homogeneous porous molded product can be obtained. The melt viscosity can be adjusted by adjusting the monomer charging ratio at the time of polymerization of the polyarylene sulfide resin, controlling the polymerization time, blending polyarylene sulfide resins having different melt viscosities, and the like.

The average particle size of the polyarylene sulfide resin powder is 5 μm or more and 100 μm or less, preferably 10 μm or more and 90 μm or less, and more preferably 15 μm or more and 80 μm or less. By setting the average particle size to 5 μm or more and 100 μm or less, the adhesion between the polyarylene sulfide resin fine particles can be enhanced, and when the above melting point Tm1 is satisfied, the temperature exceeds 300 ° C. or 1500 MPa at the time of press molding. It is possible to obtain a porous molded body having high strength without increasing the pressure. Since it is not necessary to raise the temperature or high pressure during press molding, it is possible to prevent the porosity of the obtained porous molded product from decreasing. As a result, it is possible to obtain a porous molded product having excellent dielectric properties, air permeability and permeability in addition to high strength. On the other hand, when the average particle size exceeds the above range, it is difficult to obtain a porous molded product having high strength unless the temperature is high or high. The method for measuring the "average particle size" is as described above.

The ratio of the maximum particle size to the average particle size (maximum particle size / average particle size) of the polyarylene sulfide resin powder is preferably 6.5 or less, and more preferably 5.5 or less. The lower limit is not particularly limited and may be 1 or more. The "maximum particle size" means the maximum value among the values measured by the laser diffraction / scattering type particle size distribution measurement method. By setting the ratio of the maximum particle size to the average particle size (maximum particle size / average particle size) to 6.5 or less, the adhesion between the polyarylene sulfide resin fine particles is further enhanced, and a porous molded body having higher strength is obtained. Can be.

The production of the polyarylene sulfide resin powder having the average particle size is not particularly limited, and the polyarylene sulfide resin obtained by the method for producing the polyarylene sulfide resin can be used as it is as the resin powder, or the above. Polyarylene sulfide resin molded into pellets, fibers, films, etc. was crushed by dry crushing, wet crushing, and freezing crushing using a jet mill, bead mill, hammer mill, ball mill, cutter mill, stone mill type grinder, etc. You can also use things. In addition, a method of dissolving the polyarylene sulfide resin in a solvent and then spray-drying, a poor solvent precipitation method in which an emulsion is formed in a solvent and then contacted with a poor solvent, and an organic solvent after forming an emulsion in a solvent are used. An in-liquid drying method or the like for drying and removing can also be used. It is also possible to use a method of mixing the polyarylene sulfide and the thermoplastic resin and then dissolving and removing the thermoplastic resin with a solvent to obtain a polyarylene sulfide resin powder having the above average particle size.

The polyarylene resin fine particles constituting the polyarylene sulfide resin powder preferably have a predetermined circularity. That is, the polyarylene sulfide resin powder preferably has an average circularity of 0.70 or more and 1.00 or less, and more preferably 0.80 or more and 1.00 or less, as measured by the dynamic image analysis method. preferable. By setting the average circularity within this range, it is possible to improve the adhesion between the polyarylene sulfide resin fine particles and obtain a high-strength porous molded product. The average circularity is determined from the following formula (II) from the area A and the circumference P for 4500 fine particles in the polyarylene sulfide resin powder using a dynamic image analysis method / particle state analyzer. Calculate and use the average value.
Circularity = (4 × π × A) / P ² ... (II)

As the polyarylene sulfide resin powder, one type of polyarylene sulfide resin may be used alone, or two or more types may be used in combination. It is preferable to use a blend of two or more kinds of polyarylene sulfide resin powders from the viewpoint that the strength of the obtained porous molded product can be easily controlled. The total amount of the polyarylene sulfide resin powder used is preferably 30% by volume or more, more preferably 50% by volume or more in the porous molded product. The upper limit value is not particularly limited and may be, for example, 100% by volume or less.

(Porous molded body)
Since the porous molded body is formed by using the above-mentioned polyarylene sulfide resin powder, it has excellent strength and heat resistance. The porosity of the porous molded product is preferably 20% or more and 60% or less, and preferably 25% or more and 55% or less. Since the porosity is 20% or more and 60% or less, excellent dielectric properties, air permeability and permeability can be achieved while maintaining high strength. The porosity can be adjusted by setting the temperature and pressure in the press forming process within a predetermined range.

The porosity can be calculated, for example, from the filling amount of various fluids such as water and mercury under pressure, or more simply, from the relationship between the apparent density and the true density measured using a hydrometer. , Can also be obtained from the following equation (III).
Porosity (%) = (1- (apparent specific density) / (true specific density)) x 100 ... (III)

Since the porous molded body is a heat-resistant porous molded body having high strength, low dielectric constant, excellent breathability and permeability, it is a filter, a sound absorbing material, an impregnating material, a coating material, a medical-related part, and information-related. It can be preferably used in various applications such as parts and electronic parts. Among them, the porous molded body having a relative permittivity of preferably 1.0 or more and 2.5 or less, more preferably 1.2 or more and 2.0 or less at a frequency of 1 MHz is electric for information-related parts and electronic parts. -It can be preferably used for electronic parts.

[Manufacturing method of porous molded product]
The method for producing a porous molded body according to the present embodiment includes a step of press-molding a powder material containing polyarylene sulfide resin powder.

(Press molding process)
In the press molding step, the powder material containing the polyarylene sulfide resin powder is heated to a temperature of (melting point Tm1-15) ° C. or higher (melting point Tm1 + 15) ° C., preferably (melting point Tm1-10) ° C. or higher (melting point Tm1 + 15). It has a step of press molding at a temperature of ° C. or lower and a pressure of 0.1 MPa or more and 30 MPa or less, preferably 0.1 MPa or more and 20 MPa or less. The melting point Tm1 is the melting point Tm1 of the polyarylene sulfide resin powder. By the press molding step, the polyarylene sulfide resin powder is partially welded to form a porous molded body while maintaining voids at the interface where the polyarylene sulfide resin fine particles overlap each other. When the temperature is less than the above range, the adhesion between the resin fine particles in the polyarylene sulfide resin powder is poor and the porous molded body is easily destroyed.

The powder material is a powder material for a porous molded body, and contains the above-mentioned polyarylene sulfide resin powder. The polyarylene sulfide resin powder may be used alone or in combination of two or more. It is preferable to use a blend of two or more types of polyarylene sulfide resin powder because it is easy to control the semi-molten state described later and to improve the strength of the porous molded product. The powder material may be a material consisting only of the above-mentioned polyarylene sulfide resin powder, or may be a mixed material in which the above-mentioned polyarylene sulfide resin powder is mixed with a filler or other additives. .. As the filler or additive, the same filler or additive that can be blended in the above-mentioned polyarylene sulfide resin powder can be used. The amount of the polyarylene sulfide resin powder used in the mixed material is preferably 10% by mass or more, more preferably 20% by mass or more in the powder material. The amount of the filler and the additive used can be 90% by mass or less and 80% by mass or less in the powder material. As the mixing method, a conventionally known method can be used. For example, a mixing method by shaking, a mixing method accompanied by pulverization of a ball mill or the like, a mixing method using a stirring blade such as a Henschel mixer or the like can be used.

In the present embodiment, since the powder material containing the above-mentioned predetermined polyarylene sulfide resin powder is used, by press-molding within the above-mentioned temperature and pressure range, the polyarylene sulfide resin is semi-melted and press-molded. can do. By press molding in a semi-molten state, the strength of the porous molded body can be increased. Further, in the case of press molding in a semi-molten state, the porosity and strength of the porous molded body can be adjusted by adjusting the press pressure. As a result, it becomes possible to control properties such as strength, dielectric properties, air permeability and permeability of the porous molded body. For example, a porous molded body press-molded in a semi-molten state can have a porosity of 40% to 55% and a relative permittivity of less than 2. On the other hand, in the press molding in an unmelted state using only the press pressure, it is necessary to increase the press pressure to a high pressure in order to obtain a porous molded body having a desired strength, and in that case, the porosity is high. It decreases excessively and the characteristics deteriorate. For example, in the comparative example described later, the desired strength cannot be achieved unless the press pressure is set to 2000 MPa, and in that case, the porosity is reduced to less than 20% and the dielectric property is deteriorated.

The press molding method is not particularly limited, and a conventionally known method can be used. As a press forming method, for example, a powder material is filled in a jig and a temperature of (melting point Tm1-15) ° C. or higher (melting point Tm1 + 15) ° C. or lower, for example, 270 ° C. to 305 ° C., preferably 275 ° C. to 300. Examples thereof include a method of pressure molding at a temperature of ° C. and a pressure of 0.1 MPa or more and 30 MPa or less, preferably 0.1 MPa or more and 20 MPa or less. The melting point Tm1 is the melting point Tm1 of the polyarylene sulfide resin powder. After that, the porous molded product can be obtained by allowing it to cool. Since the porous molded body thus obtained is formed by using the powder material containing the above-mentioned polyarylene sulfide resin powder, it has high strength, low dielectric constant, excellent air permeability and permeability.

(Other processes)
The method for producing a porous molded product may include a step of heat-treating the polyarylene sulfide resin powder before the press molding step in order to widen the range of temperature and pressure in the above-mentioned press molding step. As the heat treatment conditions, for example, the heat treatment can be performed at 180 ° C. or higher in an oxygen atmosphere. By heat-treating at 180 ° C. or higher, partial infusibilization can be promoted, and the temperature and pressure range of the press forming process can be set to, for example, (melting point Tm1-15) ° C. or higher (melting point Tm1 + 30) ° C. or lower, and It is possible to spread the pressure from 0 MPa to 50 MPa.

As yet another step, there is a sintering step in which the porous molded body obtained in the press molding step is further heated and sintered in an oven or the like in that the adhesion between the polyarylene sulfide resin fine particles can be further improved. May be. In the sintering step, the porous molded product obtained in the press molding step is subjected to, for example, at a temperature of 270 ° C. to 305 ° C., preferably 275 ° C. to 300 ° C., for 1 hour or more and 20 hours or less, preferably 1 hour or more and 20. It can be a step of heating for less than an hour to sinter.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples do not limit the interpretation of the present invention.

[Polyarylene sulfide resin]
The polyarylene sulfide resin used in Examples and Comparative Examples is as follows.
PPS1: Polyphenylene sulfide resin, "Fortron KPS" manufactured by Kureha Corporation, (melt viscosity: 30 Pa · s (shear rate: 1216 sec ^-1 , 310 ° C))
PPS2: Polyphenylene sulfide resin, "Fortron KPS" manufactured by Kureha Corporation, (melt viscosity: 130 Pa · s (shear rate: 1216 sec ^-1 , 310 ° C))

[Example 1]
PPS1 was subjected to dry pulverization using an air flow jet mill (vertical jet crusher SK Jet O Mill manufactured by Seishin Corporation) to obtain polyarylene sulfide resin powder. The melting point Tm1, melt viscosity, average particle size and maximum particle size, and average circularity of this resin powder were measured by the methods described below. The results are shown in Table 1.
3 g of the obtained polyarylene sulfide resin powder was filled in an aluminum ring having a diameter of 40 mm, and the temperature was 290 ° C. using a hot press molding machine (“Mini Test Press-10” manufactured by Toyo Seiki Seisakusho Co., Ltd.). A porous molded product was produced under the condition of a pressure of 0.1 MPa. The porosity, strength, and relative permittivity of this porous molded product were evaluated by the methods described below. The results are shown in Table 1.

[Example 2, Comparative Examples 1 to 3]
Polyarylene sulfide resin powder was obtained in the same manner as in Example 1 except that PPS2 was used instead of PPS1. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Tables 1 and 2. Using the obtained polyarylene sulfide resin powder, a porous molded product was produced in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. The porosity, strength, and relative permittivity of the porous molded product were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2. In Comparative Example 2, the strength of the porous molded body was low, and there was a problem that it was damaged during measurement, so that the relative permittivity could not be measured.

[Example 3]
The polyarylene sulfide resin powder obtained in Example 2 is heat-treated at a temperature of 240 ° C. for 8 hours using an air circulation type dryer (“HIGH-Temp.OVEN PHH-201” manufactured by Espec Co., Ltd.) to poly. An allylene sulfide resin powder was obtained. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Table 1. Using the obtained polyarylene sulfide resin powder, a porous molded product was produced in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. The porosity, strength, and relative permittivity of the porous molded product were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
50% by mass of the polyarylene sulfide resin powder obtained in Example 2 and 50% by mass of the polyarylene sulfide resin powder obtained in Example 3 were dry-blended to obtain a polyarylene sulfide resin powder. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Table 1. Using the obtained polyarylene sulfide resin powder, a porous molded product was produced in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. The porosity, strength, and relative permittivity of the porous molded product were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 4]
PPS2 was used without pulverization to obtain polyarylene sulfide resin powder in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Table 2. Using this resin powder, an attempt was made to produce a porous molded product in the same manner as in Example 1, but the adhesion between the particles was insufficient and molding was not possible.

[Comparative Example 5]
PPS2 was heat-treated at a temperature of 240 ° C. for 4 hours using an air circulation type dryer (“HIGH-Temp.OVEN PHH-201” manufactured by Espec Co., Ltd.) to obtain polyarylene sulfide resin powder. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Table 2. The obtained polyarylene sulfide resin was used without pulverization treatment, and a porous molded product was produced in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. The porosity, strength, and relative permittivity of the porous molded product were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 6]
PPS1 was heat-treated at a temperature of 240 ° C. for 8 hours using an air circulation type dryer (“HIGH-Temp.OVEN PHH-201” manufactured by Espec Co., Ltd.) to obtain polyarylene sulfide resin powder. In the same manner as in Example 1, the melting point Tm1, the melt viscosity, the average particle size and the maximum particle size, and the average circularity of the polyarylene sulfide resin powder were measured. The results are shown in Table 2. The obtained polyarylene sulfide resin was used without pulverization treatment, and a porous molded product was produced in the same manner as in Example 1 except that the temperature and pressure conditions were as shown in Table 1. The porosity, strength, and relative permittivity of the porous molded product were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[measurement]
(Melting point Tm1)
The temperature of the peak top at the endothermic peak observed when heating (1stRUN) from room temperature at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC7000X, manufactured by Hitachi High-Tech Science Co., Ltd.) is set as the melting point Tm1. It was measured.

(Melting viscosity)
Using a capillary type leometer (Capillograph 1D manufactured by Toyo Seiki Seisakusho Co., Ltd .: piston diameter 10 mm), the cylinder temperature is 30 ° C higher than the melting point Tm1 and the shear rate is 1200 sec ^-1 , according to ISO 11443, and apparent melting. The viscosity was measured. An orifice having an inner diameter of 1 mm and a length of 10 mm was used for the measurement.

(Average particle size and maximum particle size)
The average particle size and the maximum particle size were measured using a laser diffraction / scattering type particle size distribution measuring device (LA-920, manufactured by HORIBA, Ltd.). The average particle size is an arithmetic average particle size based on the volume. The maximum particle size / average particle size was calculated from the obtained average particle size and the maximum particle size.

(Circularity)
Using a dynamic image analysis method / particle state analyzer (PITA-3, manufactured by Seishin Corporation), the circularity of 4500 fine particles in the polyarylene sulfide resin powder is calculated from the area A and the circumference P as follows. It was calculated from the formula (II) of the above, and the average value was taken as the average circularity of the resin powder. The "circularity" in Table 1 indicates the average circularity.
Circularity = (4 × π × A) / P ² ... (II)

[evaluation]
The porosity, strength and relative permittivity of the porous molded products obtained in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1.

(Porosity)
The porosity was calculated from the apparent density and the true density by the following formula (III). The apparent density was measured using a hydrometer (“Electronic Hydrometer SD-120L” manufactured by Mirage Co., Ltd.). The true specific gravity was measured by using the same hydrometer to prepare a non-perforated molded product by injection molding.
Porosity = (1- (apparent specific density) / (true specific density)) x 100 ... (III)

(Strength)
Using a Barber Colman Company, a load of 80 N was applied with a glass plate having a diameter of 40 mm and a thickness of 3 mm placed on the porous molded body. The strength of the porous body was evaluated according to the following criteria.
Good: Destruction is not recognized Bad: Destruction is recognized

(Relative permittivity)
The relative permittivity at 1 MHz was measured using a dielectric constant measuring device (Concept 42, manufactured by Novocontrol Technologies, Inc.).

As is clear from Table 1, the porous molded product of the example did not show any fracture in the strength evaluation and has excellent strength. Further, the porosity was 20% or more and 60% or less, showing a low dielectric constant. Therefore, the porous molded article of the example can achieve excellent dielectric properties, air permeability and permeability while maintaining high strength.

Claims (9)

A polyarylene sulfide resin powder having an average particle size of 5 μm or more and 90 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less is used, and the porosity is 20% or more and 60. % Or less ,
A porous molded body having an average circularity of 0.70 or more and 1.00 or less as measured by a dynamic image analysis method for polyarylene sulfide resin powder . A polyarylene sulfide resin powder having an average particle size of 5 μm or more and 90 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less is used, and the porosity is 20% or more and 60%. Is below
Cylinder temperature and shear rate of polyarylene sulfide resin powder, which is 30 ° C higher than the melting point Tm1 measured by a differential scanning calorimeter, and a shear rate of 1200 sec. ^-1 A porous molded product having a melt viscosity measured in 1 and 25 Pa · s or more and 5000 Pa · s or less. A polyarylene sulfide resin powder having an average particle size of 5 μm or more and 90 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less is used, and the porosity is 20% or more and 60%. Is below
A porous molded body in which the ratio of the maximum particle size to the average particle size (maximum particle size / average particle size) of the polyarylene sulfide resin powder is 6.5 or less. The porous molded body according to claim 2 or 3 , wherein the average circularity measured by the dynamic image analysis method of the polyarylene sulfide resin powder is 0.70 or more and 1.00 or less. Claimed that the melt viscosity of the polyarylene sulfide resin powder measured at a cylinder temperature 30 ° C. higher than the melting point Tm1 measured by a differential scanning calorimeter and a shear rate of 1200 sec ^-1 is 25 Pa · s or more and 5000 Pa · s or less. Item 2. The porous molded body according to Item 1 , 3 or 4 . The porous molding according to claim 1 , 2, 4 or 5 , wherein the ratio of the maximum particle size to the average particle size (maximum particle size / average particle size) of the polyarylene sulfide resin powder is 6.5 or less. body. The porous molded product according to any one of claims 1 to 6 , wherein the relative permittivity at a frequency of 1 MHz is 1.0 or more and 2.5 or less. The method for producing a porous molded product according to any one of claims 1 to 7 .
A powder material containing a polyarylene sulfide resin powder having an average particle size of 5 μm or more and 100 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less (melting point Tm1-15). A manufacturing method comprising a step of press molding at a temperature of ° C. or higher (melting point Tm1 + 15) ° C. or lower and a pressure of 0.1 MPa or higher and 30 MPa or lower. The method for producing a porous molded product according to any one of claims 1 to 7.
A step of hot press molding a powder material containing a polyarylene sulfide resin powder having an average particle size of 5 μm or more and 100 μm or less and a melting point Tm1 measured by a differential scanning calorimeter of 250 ° C. or more and 300 ° C. or less. Have, manufacturing method.