JP6282802B2 - Semi-aromatic polyamide powder and method for producing the same - Google Patents

Description

  The present invention relates to a semi-aromatic polyamide powder having excellent fluidity.

  Semi-aromatic polyamides are widely used as molded members for electric / electronic parts, automobile parts and the like because of their excellent mechanical properties. Semi-aromatic polyamide is usually produced as a granular material, but due to its shape as a granular material, stagnation occurs when it is supplied from a raw material charging port to a molding machine or a kneader. There is a problem in handling that a bridge is generated near the supply port of the kneader.

  As a method for solving the above problems, for example, a method of improving fluidity by covering each particle of a granular material with a silicone resin and improving the surface state (Patent Document 1), or a small particle diameter. A method for improving the fluidity of a granular material by removing the granular material in advance is known. However, such a method requires secondary processing after the powder is obtained.

Japanese Patent No. 3788695

  An object of this invention is to provide the semi-aromatic polyamide powder body excellent in fluidity | liquidity, without carrying out secondary processing in view of this prior art.

As a result of intensive studies to solve such problems, the present inventors have determined that the content of the monocarboxylic acid component is a specific amount and synthesize nylon salt powder granules at a temperature of less than 180 ° C. The present inventors have found that semi-aromatic polyamide particles having excellent fluidity can be obtained, and have reached the present invention.

That is, the gist of the present invention is as follows.
[1] It is composed of an aromatic dicarboxylic acid component, an aliphatic diamine component, and a monocarboxylic acid component, and the monocarboxylic acid is stearic acid, caprylic acid, lauric acid, or behenic acid, and the following conditions (a) to ( Semi-aromatic polyamide powder satisfying d).
(A) The content of the monocarboxylic acid component is 0 to 3.5 mol% with respect to the total monomer components constituting the semi-aromatic polyamide.
(B) The aliphatic diamine component is 1,10-decanediamine.
(C) Particles having a particle size of 50 μm or less are 20% by volume or less.
(D) The mode diameter is 100 μm or more.
[2] The semi-aromatic polyamide powder according to [1], wherein the aromatic dicarboxylic acid component contains terephthalic acid.
[3] A molded product obtained by molding the semi-aromatic polyamide powder according to [1] or [2].
[4] Using an aromatic dicarboxylic acid having a mode diameter of 80 μm or more as a raw material, while maintaining a temperature of less than 180 ° C., the aromatic dicarboxylic acid is in a liquid state so as to maintain a granular state. A monocarboxylic acid and an aliphatic diamine are added to produce nylon salt granules, and the resulting nylon salt granules are polymerized to obtain a polymer [1] or [2] A process for producing a semi-aromatic polyamide powder according to claim 1.

  According to the present invention, a semi-aromatic polyamide powder having excellent fluidity can be provided. Moreover, according to the manufacturing method of this invention, the yield at the time of manufacture can be made high.

1 is a graph showing the particle size distribution of a semi-aromatic polyamide powder obtained in Example 1. FIG. It is a figure which shows the particle size distribution of the semi-aromatic polyamide granular material obtained by the comparative example 2.

Hereinafter, the present invention will be described in detail.
The semi-aromatic polyamide powder of the present invention is a semi-aromatic polyamide powder composed of an aromatic dicarboxylic acid component, an aliphatic diamine component, and a monocarboxylic acid component.

  Examples of the aromatic dicarboxylic acid component constituting the semi-aromatic polyamide include terephthalic acid, phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. Among them, terephthalic acid is preferable. Heat resistance can be improved by containing terephthalic acid as an aromatic dicarboxylic acid component. As the aromatic dicarboxylic acid component, two or more aromatic dicarboxylic acids may be used in combination.

  Dicarboxylic acid components include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and cyclohexanedicarboxylic acid An alicyclic dicarboxylic acid such as When the aliphatic dicarboxylic acid or the alicyclic dicarboxylic acid is contained, the content thereof is preferably 5 mol% or less, and more preferably substantially free from the total number of moles of the raw material monomers.

The aliphatic diamine component constituting the semiaromatic polyamide needs to be 1,10-decanediamine.

  As an amine component, you may contain diamine components, such as alicyclic diamines, such as cyclohexanediamine, and aromatic diamines, such as xylylenediamine and benzenediamine. When alicyclic diamine or aromatic diamine is contained, the content thereof is preferably 5 mol% or less, and more preferably substantially not contained, relative to the total number of moles of raw material monomers.

  If necessary, the semiaromatic polyamide may contain lactams such as caprolactam and laurolactam, and ω-aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid.

  In the present invention, the content of the monocarboxylic acid component constituting the semi-aromatic polyamide needs to be 0 to 3.5 mol% with respect to the total monomer components constituting the semi-aromatic polyamide. It is preferable that it is -2.5 mol%. When the content of the monocarboxylic acid component exceeds 3.5 mol%, the angle of repose of the semi-aromatic polyamide powder becomes large and the fluidity becomes poor. Moreover, since the molecular weight of the obtained semi-aromatic polyamide powder becomes small and the mechanical properties of a molded body using the same are lowered, it is not preferable. In addition, melt fluidity | liquidity can also be improved by content of the said monocarboxylic acid component being 0.3-3.5 mol%.

The molecular weight of the monocarboxylic acid component used in the semi-aromatic polyamide needs to be 140 or more, and preferably 170 or more. By using a monocarboxylic acid having a molecular weight of 140 or more, the angle of repose can be made smaller, the melt fluidity can be improved, and the outgassing during high temperature use can be suppressed. In the present invention, the molecular weight of the monocarboxylic acid refers to the molecular weight of the starting monocarboxylic acid.

  Examples of the monocarboxylic acid component include aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids, and among them, aliphatic monocarboxylic acids are preferable. Examples of the aliphatic monocarboxylic acid having a molecular weight of 140 or more include caprylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Of these, stearic acid is preferred because of its high versatility. Examples of the alicyclic monocarboxylic acid having a molecular weight of 140 or more include 4-ethylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, and 4-laurylcyclohexanecarboxylic acid. Examples of the aromatic monocarboxylic acid having a molecular weight of 140 or more include 4-ethylbenzoic acid, 4-hexylbenzoic acid, 4-laurylbenzoic acid, alkylbenzoic acids, 1-naphthoic acid, 2-naphthoic acid, and their Derivatives. As the monocarboxylic acid component, two or more kinds of monocarboxylic acids may be used in combination, or a monocarboxylic acid having a molecular weight of less than 140 may be used in combination.

  The semi-aromatic polyamide preferably has a melting point of 300 ° C. or higher, and more preferably 310 ° C. or higher. By increasing the melting point of the semi-aromatic polyamide, it can be used as a molded article in a higher temperature environment.

  The semi-aromatic polyamide preferably has a relative viscosity of 1.8 or more, more preferably 1.8 to 2.8 when measured in 96% sulfuric acid at 25 ° C. and a concentration of 1 g / dL. More preferably, it is 1.9 to 2.5. The relative viscosity can be used as an index of molecular weight.

  The semi-aromatic polyamide powder of the present invention is a step (i) of obtaining a nylon salt from an aromatic dicarboxylic acid component, an aliphatic diamine component, and a monocarboxylic acid component, and a step of polymerizing the obtained nylon salt It can be produced by the method comprising (ii).

In the step (i), a liquid monocarboxylic acid and an aliphatic diamine are added to the aromatic dicarboxylic acid so as to keep the aromatic dicarboxylic acid in a granular state while maintaining a temperature of less than 180 ° C. and nylon. Make salt granules. In step (i), the semiaromatic dicarboxylic acid is solid, and the monocarboxylic acid and aliphatic diamine are liquid, so that the semiaromatic dicarboxylic acid can easily be reacted with the monocarboxylic acid and aliphatic diamine. Can do. In step (i), the water content is preferably 5% by mass or less based on the total amount of the aromatic dicarboxylic acid particles, monocarboxylic acid and aliphatic diamine. By adjusting the water content to 5% by mass or less, the amount of triamine by-product that causes gelation can be reduced.

  In the step (ii), the nylon salt obtained in the step (i) is solid-phase polymerized at a temperature lower than the melting point of the semi-aromatic polyamide to be finally produced to increase the molecular weight to a predetermined molecular weight. A group polyamide powder is obtained. The solid phase polymerization is preferably performed in a stream of inert gas such as nitrogen at a polymerization temperature of 180 to 270 ° C. and a reaction time of 0.5 to 10 hours.

  In the present invention, after step (ii), if necessary, a mass of 2 mm or more may be removed from the polymer obtained in step (ii). Although it does not specifically limit as a method of removing a lump, For example, the method of removing using a sieve with an opening of about 2-5 mm is mentioned.

  The reaction apparatus in step (i) and step (ii) is not particularly limited, and a known apparatus may be used. Step (i) and step (ii) may be performed by the same apparatus or may be performed by different apparatuses. In addition, the heating method is not particularly limited, but includes a method of heating the reaction vessel with a medium such as water, steam, heat transfer oil, a method of heating the reaction vessel with an electric heater, heat of stirring generated by stirring, etc. A method of using frictional heat accompanying the movement of an object can be mentioned. Moreover, you may combine these methods.

  In the production method of the present invention, a polymerization catalyst may be used to increase the efficiency of polymerization. Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid, and salts thereof. The addition amount of the polymerization catalyst is usually 2 mol% or less with respect to the total number of moles of raw material monomers. Is preferred.

  In this invention, it is preferable that the mode diameter of the aromatic dicarboxylic acid granular material used at process (i) is 80 micrometers or more, and it is more preferable that it is 100-150 micrometers. In the production method of the present invention, the raw material aromatic dicarboxylic acid granules react with the diamine component or monocarboxylic acid component to form nylon salt powder granules whose particle diameter is increased by the amount of reaction, The nylon salt powder particles tend to maintain the particle diameter even when the molecular weight is increased. Therefore, it is speculated that the mode diameter of the semi-aromatic polyamide powder after the high molecular weight can be increased to 100 μm or more by setting the mode diameter of the aromatic dicarboxylic acid used in the step (i) to 80 μm or more. The

Moreover, in this invention, content of the particle | grains whose particle diameter of a semi-aromatic polyamide granular material is 50 micrometers or less can be 20 volume% or less. When the nylon salt particles are synthesized at a temperature of 180 ° C. or higher in the production method of the present invention, the hardness of the nylon salt particles is reduced by heat, the particles of the nylon salt particles are crushed by friction, and the particle diameter is Nylon salt granules having a large number of particles of 50 μm or less are synthesized, and the semi-aromatic polyamide particles obtained therefrom tend to have more particles having a particle diameter of 50 μm or less. However, in the production method of the present invention, since the nylon salt granules are synthesized at a temperature of 180 ° C. or less, the crushing of the particles is reduced, and the particles having a particle diameter of the nylon salt granules of 50 μm or less are reduced. The As a result, it is presumed that particles having a particle diameter of 50 μm or less can be reduced to 20% by volume or less even in a semi-aromatic polyamide powder having a high molecular weight.

  In the semi-aromatic polyamide powder of the present invention, particles having a particle size of 50 μm or less can be made 20% by volume or less, and the mode diameter can be made 100 μm or more. can do. Therefore, there is no need to perform secondary processing of the powder, and a device such as a vibrator is installed under the hopper to forcibly supply it to a molding machine or kneader, or a heating device is installed in the piping to force There is no need to allow the resin to flow. When the content of particles having a particle diameter of 50 μm or less exceeds 20% by volume or when the mode diameter is less than 100 μm, the angle of repose exceeds 40 degrees, and the fluidity decreases as a granular material. Therefore, it is not preferable.

When a method of synthesizing a nylon salt so as to maintain the state of a granular material under heating as in the production method of the present invention, a lump as a foreign matter that does not affect the particle size distribution may be generated. . These can be easily removed using, for example, a sieve having an opening of about 2 mm. According to the production method of the present invention, by adopting a temperature condition of less than 180 ° C. for the synthesis of the nylon salt, the formation of these lumps can be suppressed, the yield of the granular material can be improved, and the yield can be improved. The rate can be 95% by mass or more.

  Various additives may be added to the semi-aromatic polyamide powder of the present invention as necessary. Examples of additives include fibrous reinforcement, plate-like reinforcement, impact resistance improver, antistatic agent, conductivity-imparting agent, thermally conductive filler, aliphatic polyamide, amorphous polyamide, thermal stabilizer, light Stabilizers, slidability improvers, flame retardants, flame retardant aids, and pigments. Additives may be used alone or in combination.

  Examples of the fibrous reinforcing material include carbon fiber, glass fiber, boron fiber, asbestos fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber, wholly aromatic polyamide fiber, polybenzoxazole fiber, polytetrafluoroethylene fiber, and kenaf fiber. , Bamboo fiber, hemp fiber, bagasse fiber, high-strength polyethylene fiber, alumina fiber, silicon carbide fiber, potassium titanate fiber, brass fiber, stainless steel fiber, steel fiber, ceramic fiber, basalt fiber, sepiolite, and palygorskite. By adding a fibrous reinforcing material, the mechanical strength can be improved. Among them, glass fiber, carbon fiber, and metal fiber are preferable because of high heat resistance and easy availability. Two or more kinds of fibrous reinforcing materials may be used in combination. The fibrous reinforcing material may be surface-treated with a silane coupling agent. Examples of silane coupling agents include vinyl silanes, acrylic silanes, epoxy silanes, and amino silanes, and aminosilane coupling agents are preferred because of their high adhesion to semi-aromatic polyamides.

  The average fiber length of the fibrous reinforcing material is preferably 0.1 to 7 mm, and more preferably 0.5 to 6 mm. When the average fiber length of the fibrous reinforcing material is 0.1 to 7 mm, the mechanical properties of the semi-aromatic polyamide can be improved without adversely affecting the moldability. Moreover, it is preferable that an average fiber diameter is 3-20 micrometers, and it is more preferable that it is 5-13 micrometers. By setting the average fiber diameter to 3 to 20 μm, it is possible to improve the mechanical properties of the semi-aromatic polyamide while reducing breakage during melt-kneading. The cross-sectional shape is preferably a circular cross-section, but may be a rectangle, an ellipse (flat), or any other irregular cross-section as necessary.

  When using a fibrous reinforcing material, the content is preferably 5 to 200 parts by mass, more preferably 10 to 180 parts by mass, with respect to 100 parts by mass of the semi-aromatic polyamide. It is more preferable to set it as a part, and it is most preferable to set it as 30-130 mass parts.

  The method for adding the additive is not particularly limited, but a melt kneading method using a biaxial kneader is preferably used. The kneading temperature needs to be equal to or higher than the melting point of the semi-aromatic polyamide, and is preferably less than (melting point + 100 ° C.). By setting the kneading temperature to be higher than the melting point of the semi-aromatic polyamide and lower than (melting point + 100 ° C), the kneading machine is overloaded and the vent-up is suppressed, but the decomposition and yellowing of the semi-aromatic polyamide are suppressed. can do. The kneaded resin composition is preferably made into a strand and pelletized.

  A molded product can be obtained by injection molding the semi-aromatic polyamide powder of the present invention and a resin composition using the same. Although it does not specifically limit as an injection molding machine used for injection molding, For example, a screw in-line type injection molding machine and a plunger type injection molding machine are mentioned. Semi-aromatic polyamide and its resin composition heated and melted in the cylinder of the injection molding machine are weighed for each shot, injected into the mold in a molten state, cooled to a predetermined shape, solidified, and then molded. Removed from the mold as a body. The resin temperature at the time of injection molding needs to be equal to or higher than the melting point of the semi-aromatic polyamide, and is preferably less than (melting point + 100 ° C.). In addition, when using a semi-aromatic polyamide granular material for injection molding, it is preferable that the semi-aromatic polyamide granular material is fully dried. A powder having a high moisture content may deteriorate fluidity, cause poor biting, or foam in a cylinder of an injection molding machine, making it difficult to obtain an optimal molded product. The moisture content of the semi-aromatic polyamide powder used for injection molding is preferably less than 0.3% by mass, and more preferably less than 0.1% by mass.

  The semi-aromatic polyamide powder of the present invention can be formed into a film or sheet by a known film forming method such as T-die extrusion or inflation molding. The film or sheet formed by molding the semi-aromatic polyamide powder of the present invention can be used for, for example, a speaker diaphragm and a film capacitor.

  Further, the semi-aromatic polyamide powder of the present invention can be formed into various fibers by a known spinning method such as a melt spinning method, a flash spinning method, or an electrospinning method. The fiber formed by molding the semi-aromatic polyamide powder of the present invention includes, for example, an air bag base fabric, a heat resistant filter, a reinforcing fiber for a radiator hose, a bristle for a brush, a fishing line, a tire cord, an artificial grass, a carpet, and a fish net. , Ropes, filter fibers, and seat sheet fibers.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.
1. Analysis Method The physical properties of the semi-aromatic polyamide were measured by the following method.

(1) Ratio of particles with a mode diameter and particle size of 50 μm or less Disperse the granular material from which the aggregates have been removed using a sieve with an opening of 2 mm in distilled water, and release the aggregation by applying ultrasonic waves for 1 minute. did. Then, using a laser diffraction / scattering particle size distribution analyzer LA-920 manufactured by HORIBA, the ratio of particles having a mode diameter and a particle diameter of 50 μm or less was measured at a concentration at which the absorbance was in an appropriate range.

(2) Yield Calculated from the mass before and after removing the lump.

(3) Angle of repose Using a bulk specific gravity meter (JISK6721 compliant) manufactured by Kuramochi Scientific Instruments, 100 cm ³ of semi-aromatic polyamide particles were flowed from above and deposited in a conical shape. The height of the deposit and the length of the base were measured, an isosceles triangle was drawn, and the base angle of the isosceles triangle was measured as the inclination angle of the surface of the deposit.

(4) Melting point Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer, Inc., the temperature was raised to 350 ° C. at a rate of temperature increase of 20 ° C./min, held at 350 ° C. for 5 minutes, and at a rate of temperature decrease of 20 ° C./min. The temperature was lowered to 25 ° C. After maintaining at 25 ° C for 5 minutes, the top of the endothermic peak when the temperature was measured again at a rate of temperature increase of 20 ° C / min was defined as the melting point.

(5) Relative viscosity Using 96% sulfuric acid as a solvent, the relative viscosity was measured at a concentration of 1 g / dL and 25 ° C.

(6) Melt flow rate (MFR)
Based on JISK7210, the measurement was performed under the conditions of a load of 1.2 kgf / cm ² and a temperature of 350 ° C.

2. Raw materials The raw materials used are shown below.
(1) Aromatic dicarboxylic acid component / TPA: terephthalic acid (melting point: 300 ° C. or higher, mode diameter 130 μm)
IPA: isophthalic acid (melting point: 300 ° C. or higher, mode diameter 100 μm)

(2) Aliphatic diamine component / DDA: 1,10-decanediamine (melting point: 62 ° C.)
HMDA: 1,6-hexanediamine (melting point: 42 ° C.)
NDA: 1,9-nonanediamine (melting point: 36 ° C.)

(3) Monocarboxylic acid component STA: stearic acid (molecular weight: 284, melting point: 70 ° C.)
CP: caprylic acid (molecular weight: 144, melting point: 15-17 ° C.)
LA: lauric acid (molecular weight: 200, melting point: 44-46 ° C.)
BHA: behenic acid (molecular weight: 341, melting point: 74-78 ° C.)
BA: Benzoic acid (molecular weight: 122, melting point: 122 ° C.)
CA: caproic acid (molecular weight: 116, melting point: −3 ° C.)

Example 1
4.70 kg of powdered TPA as an aromatic dicarboxylic acid component and 9.3 g of sodium hypophosphite monohydrate as a polymerization catalyst are placed in a ribbon blender type reactor and stirred at 30 rpm under nitrogen sealing. While heating to 150 ° C. Thereafter, while maintaining the temperature at 150 ° C. and maintaining the rotation speed at 30 rpm, using a liquid injection device, 5.15 kg of DDA heated to 120 ° C. as an aliphatic diamine component and a molecular weight of 284 as a monocarboxylic acid component 0.15 kg of STA was continuously added over 2.5 hours (continuous liquid injection method) to obtain a nylon salt. The monomer ratio of the raw materials was TPA: DDA: STA = 48.0: 50.0: 2.0. During the production of the nylon salt, the temperature rise due to the heat of reaction was controlled and the temperature was kept at 173 ° C.
The obtained nylon salt was polymerized in the same reaction apparatus by heating at 250 ° C. under a nitrogen stream at 30 rpm for 8 hours to obtain a polymer.
From the obtained polymer, a lump was removed using a sieve having an opening of 2 mm to obtain a semi-aromatic polyamide powder.

Examples 2 to 10, Reference Examples 1 to 10, Comparative Examples 1 to 3
A semi-aromatic polyamide powder was obtained in the same manner as in Example 1 except that the type and content of each component and the production temperature of the nylon salt were changed as shown in Table 1.

Comparative Example 4
The semi-aromatic polyamide powder of Comparative Example 1 was classified using a Dalton vibration sieve machine manufactured by Dalton Co., with a sieve opening of 50 μm, and the powder remaining on the sieve was collected.

Table 1 shows the resin composition, production conditions, particle characteristics, and resin characteristics of the semi-aromatic polyamide particles obtained in Examples 1 to 10, Reference Examples 1 to 10, and Comparative Examples 1 to 4.

Since the semi-aromatic polyamide powders of Examples 1 to 10 had a monocarboxylic acid component content of a specific amount or less and synthesized a nylon salt at a temperature of less than 180 ° C., all had a mode diameter of 100 μm or more. The particles having a particle diameter of 50 μm or less were 20% by volume or less. As a result, the angle of repose was 40 degrees or less, and the fluidity was good. Moreover, the yield of the granular material at the time of manufacture was as high as 95% or more.
From the comparison between Examples 1 to 9, Reference Examples 1 and 2 , and Reference Examples 3 to 9 , the semi-aromatic polyamide using a monocarboxylic acid having a molecular weight of 140 or more is a semi-aromatic polyamide using benzoic acid and In contrast, the angle of repose is small and the MFR is 5 g / 10 min or higher.
From the comparison between Examples 1 and 2 and Reference Example 1 , it can be seen that the melting point is higher when 1,10-decanediamine is used as the aliphatic diamine component than when 1,9-nonanediamine is used.
From the comparison of Examples 1, 2, 6 to 9 and Example 10 , it can be seen that when the content of the monocarboxylic acid component is less than 0.3 mol%, the MFR becomes small.
From the comparison between Examples 1 to 5 and Reference Example 10 , it can be seen that MFR increases when a monocarboxylic acid having a molecular weight of less than 140 is used as the monocarboxylic acid component.

Since the semi-aromatic polyamide powders of Comparative Examples 1 and 2 were synthesized with a nylon salt at a temperature of 180 ° C. or less , the particles having a particle diameter of 50 μm or less exceeded 20% by volume, and the mode diameter was 100 μm. Therefore, the angle of repose was 40 degrees or more. Moreover, the yield was low.
Since the semi-aromatic polyamide powder of Comparative Example 3 contained a large amount of monocarboxylic acid component, particles having a particle diameter of 50 μm or less exceeded 20% by volume. Therefore, the angle of repose was large. Moreover, since many were end-capped with monocarboxylic acid, the relative viscosity was low.
The semi-aromatic aromatic polyamide powder of Comparative Example 4 is a granular material remaining on the sieve after classification of the semi-aromatic polyamide powder of Comparative Example 1 with a sieve opening of 50 μm. In the granular material, the proportion of particles of 50 μm or less was 20% by volume or less, but since the mode diameter was 100 μm or less, the angle of repose was 40 degrees or more. Moreover, the yield was low.

Claims (4)

It is composed of an aromatic dicarboxylic acid component, an aliphatic diamine component and a monocarboxylic acid component, and the monocarboxylic acid component is stearic acid, caprylic acid, lauric acid or behenic acid, and the following conditions (a) to (d) Semi-aromatic polyamide powder satisfying the requirements.
(A) The content of the monocarboxylic acid component is 0 to 3.5 mol% with respect to the total monomer components constituting the semi-aromatic polyamide.
(B) The aliphatic diamine component is 1,10-decanediamine.
(C) Particles having a particle size of 50 μm or less are 20% by volume or less.
(D) The mode diameter is 100 μm or more. The semi-aromatic polyamide powder according to claim 1, wherein the aromatic dicarboxylic acid component contains terephthalic acid. A molded article obtained by molding the semi-aromatic polyamide powder according to claim 1 or 2. Using aromatic dicarboxylic acid with a mode diameter of 80 μm or more as a raw material, liquid monocarboxylic acid in aromatic dicarboxylic acid so that the aromatic dicarboxylic acid maintains the state of particles while maintaining the temperature below 180 ° C. 3. A semi-fragrance according to claim 1, wherein a nylon salt powder is prepared by adding styrene and an aliphatic diamine, and a polymer is obtained by increasing the molecular weight of the obtained nylon salt powder. Method for producing a polyamid polyamide powder.