阅读说明：本技术 聚酰胺树脂组合物及将其成型而成的成型体 (Polyamide resin composition and molded article obtained by molding same ) 是由 浅井美穗 三井淳一 于 2020-04-17 设计创作，主要内容包括：本发明提供一种聚酰胺树脂组合物,其特征在于,含有熔点为290～330℃的半芳香族聚酰胺(A)和纤维状强化材料(B),在温度100℃、拉伸载荷75MPa的测定条件下经过100小时时的流动方向的蠕变应变量为2.0％以下。(The present invention provides a polyamide resin composition containing a semi-aromatic polyamide (A) having a melting point of 290 to 330 ℃ and a fibrous reinforcing material (B), wherein the creep strain amount in the flow direction when 100 hours elapse under the measurement conditions of a temperature of 100 ℃ and a tensile load of 75MPa is 2.0% or less.)

1. A polyamide resin composition characterized by containing a semi-aromatic polyamide (A) having a melting point of 290 to 330 ℃ and a fibrous reinforcing material (B),

the creep strain amount at 100 hours under the measurement conditions of 100 ℃ and 75MPa of tensile load is 2.0% or less.

2. The polyamide resin composition according to claim 1, wherein the semi-aromatic polyamide (a) contains a dicarboxylic acid component and a diamine component as constituent components, the dicarboxylic acid component contains terephthalic acid as a main component, and the diamine component contains 1, 10-decamethylenediamine as a main component.

3. The polyamide resin composition according to claim 1 or 2, wherein the fibrous reinforcing material (B) is a carbon fiber having a tensile strength of 4000 to 4800 MPa.

4. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 3.

5. Shaped body according to claim 4, characterized in that it is a rotating body.

6. The molded body according to claim 5, wherein the rotating body is an impeller.

7. The molded body according to claim 5, wherein the rotating body is a fan.

Technical Field

The present invention relates to a polyamide resin composition containing a semi-aromatic polyamide and a fibrous reinforcing material, and a molded article molded from the polyamide resin composition.

Background

In recent years, thermoplastic resins have been used in place of metals for materials constituting rotating bodies such as impellers and fans in order to reduce the weight of the materials. In recent years, a rotor is rotated at a high speed, and for example, a rotor having a maximum outer diameter of about 25mm is rotated at a high speed of 100000 rpm. The rotating body rotating at such a high speed is required to have heat resistance, strength in the centrifugal direction, dimensional accuracy, and low density, and particularly, the rotating body is required to have strength in the centrifugal direction higher than that of conventional materials in a high-temperature environment of around 100 ℃, or a small amount of tensile creep strain corresponding to dimensional accuracy.

As thermoplastic resins used as materials for impellers capable of rotating at high speed, patent document 1 discloses a mixture (alloy) of nylon 66 and polyether sulfone, patent document 2 discloses a mixture of polyether ketone and polyether imide, patent document 3 discloses polyether ether ketone, polyether ketone, and a mixture of polyether ketone and polyether imide, and patent document 4 discloses polyimide, polyamide imide, bismaleimide triazine, and polyether sulfone.

However, these thermoplastic resins are generally expensive, require a high-temperature mold during molding, and have poor flowability during molding, which causes a problem of poor design of the shape of a rotating body such as an impeller. Further, since these thermoplastic resins have a high density as a whole, the resultant rotary body has a large weight and receives a large centrifugal force when rotating at a high speed, and therefore, there is a problem that the rotational speed cannot be increased to a certain value or more.

Documents of the prior art

Patent document

Patent document 1: japanese Kokoku publication Sho 63-063597

Patent document 2: japanese laid-open patent publication No. H02-269766

Patent document 3: japanese laid-open patent publication No. H06-042302

Patent document 4: japanese examined patent publication (Kokoku) No. 01-111102

Disclosure of Invention

The purpose of the present invention is to provide a resin composition which is less expensive than conventional resin compositions, has a low density, has excellent fluidity, can be molded at a low mold temperature of 120 ℃ or lower into a molded article having excellent appearance, and has excellent dimensional accuracy in a high-temperature environment.

The present inventors have conducted extensive studies to solve the above problems, and as a result, have found that a resin composition containing a specific resin and a reinforcing material and having a specific creep strain amount can solve the above problems, and finally have completed the present invention.

The polyamide resin composition of the present invention is characterized in that:

comprising a semi-aromatic polyamide (A) having a melting point of 290 to 330 ℃ and a fibrous reinforcing material (B),

and has a creep strain amount of 2.0% or less when the creep strain amount is measured for 100 hours under the conditions of a temperature of 100 ℃ and a tensile load of 75 MPa.

According to the polyamide resin composition of the present invention, the semi-aromatic polyamide (a) preferably contains a dicarboxylic acid component and a diamine component as constituent components, the dicarboxylic acid component containing terephthalic acid as a main component, and the diamine component containing 1, 10-decamethylenediamine as a main component.

According to the polyamide resin composition of the present invention, the fibrous reinforcing material (B) is preferably a carbon fiber having a tensile strength of 4000 to 4800 MPa.

The molded article of the present invention is molded from the polyamide resin composition.

The molded article of the present invention is preferably a rotary body.

According to the molded article of the present invention, the rotating body is preferably an impeller.

According to the molded article of the present invention, the rotating body is preferably a fan.

According to the present invention, a resin composition having high heat resistance, low density, excellent fluidity, and a small creep strain amount in a high temperature environment of around 100 ℃, and a molded article having excellent appearance comprising the resin composition can be provided, and the molded article of the present invention can be preferably used for a rotating body such as an impeller or a fan.

Drawings

Fig. 1 is a perspective view of an impeller which is an example of the molded article of the present invention.

Detailed Description

The polyamide resin composition of the present invention contains a semi-aromatic polyamide (a) and a fibrous reinforcing material (B).

In the present invention, the semi-aromatic polyamide (a) contains a dicarboxylic acid component and a diamine component as constituent components, the dicarboxylic acid component containing an aromatic dicarboxylic acid, and the diamine component containing an aliphatic diamine.

The dicarboxylic acid component constituting the semi-aromatic polyamide (a) preferably contains terephthalic acid (T) as a main component, and the content of terephthalic acid in the dicarboxylic acid component is preferably 75 mol% or more, more preferably 85 mol% or more, and further preferably 100 mol% from the viewpoint of heat resistance and creep characteristics.

The diamine component in the semi-aromatic polyamide (A) is preferably an aliphatic diamine having 8 to 12 carbon atoms from the viewpoint of heat resistance and processability. Examples of the aliphatic diamine having 8 to 12 carbon atoms include 1, 8-octanediamine, 1, 9-nonanediamine, 1, 10-decanediamine, 1, 11-undecanediamine, and 1, 12-dodecanediamine, and these may be used alone or in combination. Among them, the diamine component preferably contains 1, 10-decamethylenediamine as a main component from the viewpoint of high versatility, and the content of 1, 10-decamethylenediamine in the diamine component is preferably 75 mol% or more, more preferably 85 mol% or more, and further preferably 100 mol% from the viewpoint of heat resistance and creep characteristics.

Specific examples of the semi-aromatic polyamide (a) in the present invention include polyamide 8T, polyamide 9T, polyamide 10T, polyamide 11T, and polyamide 12T.

The dicarboxylic acid component of the semi-aromatic polyamide (a) may contain a dicarboxylic acid other than terephthalic acid. Examples of dicarboxylic acids other than terephthalic acid include: aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, 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, and dodecanedioic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. The content of the dicarboxylic acid other than terephthalic acid is preferably less than 25 mol%, more preferably less than 15 mol% in the dicarboxylic acid component, and the dicarboxylic acid component is more preferably substantially free of dicarboxylic acids other than terephthalic acid.

The diamine component of the semi-aromatic polyamide (A) may contain a diamine other than the aliphatic diamine having 8 to 12 carbon atoms. Examples of the other diamine include aliphatic diamines such as 1, 2-ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, 1, 5-pentylenediamine, 1, 6-hexylenediamine, 1, 7-heptylenediamine, 1, 13-tridecylenediamine, 1, 14-tetradecylenediamine and 1, 15-pentadecylenediamine, alicyclic diamines such as cyclohexanediamine, and aromatic diamines such as xylylenediamine and phenylenediamine. The content of the diamine other than the aliphatic diamine having 8 to 12 carbon atoms is preferably less than 25 mol%, more preferably less than 15 mol% in the diamine component, and the diamine component further preferably does not substantially contain a diamine other than the aliphatic diamine having 8 to 12 carbon atoms.

The semi-aromatic polyamide (A) may contain, if necessary, lactams such as caprolactam and laurolactam, and omega-aminocarboxylic acids such as aminocaproic acid and 11-aminoundecanoic acid. The content thereof is preferably less than 10 mol% relative to the total mole number of the raw material monomers, and the semi-aromatic polyamide (a) is more preferably substantially free of them.

The semi-aromatic polyamide (a) preferably contains a monocarboxylic acid component as a constituent component. By containing the monocarboxylic acid, the amount of free amino groups at the terminal can be kept small, decomposition or discoloration of the polyamide due to thermal deterioration or oxidative deterioration upon heating can be suppressed, and low water absorption can be achieved because the terminal is hydrophobic. As a result, the heat resistance and the low water absorption of the resin composition obtained can be improved.

The content of the monocarboxylic acid component is preferably 0.3 to 4.0 mol%, more preferably 0.3 to 3.0 mol%, even more preferably 0.3 to 2.5 mol%, and particularly preferably 0.8 to 2.5 mol% based on all monomer components constituting the semi-aromatic polyamide (a). By setting the content of the monocarboxylic acid component to 0.3 to 4.0 mol%, the molecular weight distribution during polymerization can be reduced, the releasability during molding can be improved, and the amount of gas generated during molding can be suppressed. On the other hand, if the content of the monocarboxylic acid component is more than 4.0 mol%, the mechanical properties may be deteriorated. In the present invention, the content of the monocarboxylic acid means a ratio of a residue of the monocarboxylic acid, that is, a group obtained by removing a terminal hydroxyl group from the monocarboxylic acid, in the semi-aromatic polyamide (a).

Examples of the monocarboxylic acid component include aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids. Among them, aliphatic monocarboxylic acids are preferable because the amount of gas generated from the semi-aromatic polyamide component can be reduced, the fluidity of the resin composition can be improved, mold fouling can be reduced, and the mold release properties can be improved.

The monocarboxylic acid component is preferably a monocarboxylic acid having a molecular weight of 140 or more, and more preferably a monocarboxylic acid having a molecular weight of 170 or more. By using a monocarboxylic acid having a molecular weight of 140 or more, the mold release property can be improved, the amount of gas generated at the temperature during molding can be suppressed, and the molding flowability can be improved.

Examples of the aliphatic monocarboxylic acid having a molecular weight of 140 or more include octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid and behenic acid, 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, and examples of the aromatic monocarboxylic acid having a molecular weight of 140 or more include 4-ethylbenzoic acid, 4-hexylbenzoic acid, 4-laurylbenzoic acid, 1-naphthoic acid, 2-naphthoic acid and derivatives thereof. The monocarboxylic acid component may be used alone or in combination. Furthermore, a monocarboxylic acid having a molecular weight of 140 or more and a monocarboxylic acid having a molecular weight of less than 140 may be used in combination. In the present invention, the molecular weight of the monocarboxylic acid means the molecular weight of the monocarboxylic acid as a raw material.

In the present invention, the melting point of the semi-aromatic polyamide (A) must be 290 to 330 ℃. The polyamide resin composition of the present invention contains a semi-aromatic polyamide (A) having a melting point of 290 to 330 ℃ and a fibrous reinforcing material (B), and thus the creep strain amount can be reduced. When the melting point of the semi-aromatic polyamide (a) is less than 290 ℃, the heat resistance of the polyamide resin composition is lowered and the creep strain amount is increased, while when the melting point of the semi-aromatic polyamide (a) is more than 330 ℃, the melting processing temperature is close to the decomposition temperature, and the semi-aromatic polyamide (a) is decomposed and becomes difficult to process during the melting processing, which is not preferable.

The semi-aromatic polyamide (a) used in the present invention can be produced by a conventionally known method such as a heating polymerization method or a solution polymerization method. From the viewpoint of industrial advantage, the heating polymerization method is preferably used. Examples of the heat polymerization method include a method comprising the following steps: a step (i) of obtaining a reaction product from an aromatic dicarboxylic acid component and a diamine component, and a step (ii) of polymerizing the obtained reaction product.

Examples of the step (i) include the following methods: the dicarboxylic acid powder is heated in advance to a temperature of not less than the melting point of the diamine and not more than the melting point of the dicarboxylic acid, and the diamine is added to the dicarboxylic acid powder at this temperature so as to keep the powder state of the dicarboxylic acid substantially free of water. Other methods include the following: after a mixed solution is obtained by stirring and mixing a suspension composed of a diamine in a molten state and a solid dicarboxylic acid, a salt-forming reaction is carried out by a reaction between the dicarboxylic acid and the diamine and an oligomer-forming reaction is carried out by polymerization of the formed salt at a temperature lower than the melting point of the finally formed semi-aromatic polyamide, thereby obtaining a mixture of the salt and the oligomer. In this case, the reaction may be carried out while the reaction is being carried out, or the reaction product may be taken out once after the reaction and then crushed. The former method, in which the shape of the reaction product is easily controlled, is preferable as the step (i).

Examples of the step (ii) include the following methods: (ii) subjecting the reaction product obtained in the step (i) to solid-phase polymerization at a temperature lower than the melting point of the finally produced semi-aromatic polyamide to increase the molecular weight to a predetermined molecular weight, thereby obtaining the semi-aromatic polyamide. The solid-phase polymerization is preferably carried out in a gas stream of an inert gas such as nitrogen at a polymerization temperature of 180 to 270 ℃ for 0.5 to 10 hours.

The reaction apparatus used in the steps (i) and (ii) is not particularly limited, and any known apparatus may be used. The steps (i) and (ii) may be performed by the same apparatus, or may be performed by different apparatuses.

In the production of the semi-aromatic polyamide (a), a polymerization catalyst may be used in order to improve the polymerization efficiency. Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid, and salts thereof. In general, the amount of the polymerization catalyst added is preferably 2.0 mol% or less based on the total monomers constituting the semi-aromatic polyamide (a).

The polyamide resin composition of the present invention must contain a fibrous reinforcing material (B).

Examples of the fibrous reinforcing material (B) include glass fibers, carbon fibers, boron fibers, asbestos fibers, polyvinyl alcohol fibers, polyester fibers, acrylic fibers, aramid fibers, and polybenzo fibersOxazole fiber, 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, ceramic fiber, basalt fiber.

Wherein the fibrous reinforcing material (B) is preferably a carbon fiber having a tensile strength of 4000 to 4800 MPa.

By containing carbon fibers having a tensile strength of 4000MPa or more, the creep strain amount of the polyamide resin composition in the flow direction after 100 hours under the measurement conditions of a temperature of 100 ℃ and a tensile load of 75MPa is likely to be 2.0% or less.

On the other hand, the tensile strength of the carbon fiber contained in the polyamide resin composition is preferably not more than 4800MPa for the following reasons. That is, in the polyamide resin composition of the present invention, the melting point of the semi-aromatic polyamide (a) is 290 to 330 ℃, and therefore the actual processing temperature for melt kneading is about 330 to 400 ℃. If the resin composition contains high-strength carbon fibers having a tensile strength of more than 4800MPa, excessive shear heat generation occurs during melt kneading, and the temperature is further increased, which causes decomposition of the resin, decomposition of the surface treatment agent for the fibers, or poor dispersion of the fibers due to a decrease in viscosity. Therefore, even if the resin composition contains high-strength carbon fibers having a tensile strength of more than 4800MPa, the effect of improving the strain amount or other mechanical properties cannot be obtained, or even the effect is reduced. Further, even if decomposition or viscosity reduction at the time of melt kneading does not occur due to the inclusion of high-strength carbon fibers having a tensile strength of more than 4800MPa, the resin composition is hardened by the influence of the strength of the carbon fibers, and the fluidity is reduced. In order to suppress shear heat generation, melt kneading may be performed using an extruder with a small specification, or may be performed by setting the discharge amount and the rotation speed to be small, but the productivity is significantly lowered.

The preferred fiber length of the carbon fiber with the tensile strength of 4000-4800 MPa is 0.1-7 mm, and the more preferred fiber length is 0.5-6 mm. By setting the fiber length of the carbon fiber to 0.1 to 7mm, the mechanical properties of the resin composition can be improved without adversely affecting moldability. The carbon fiber preferably has a fiber diameter of 3 to 20 μm, more preferably 5 to 13 μm. By setting the fiber diameter of the carbon fiber to 3 to 20 μm, the breakage at the time of melt kneading can be reduced and the mechanical properties of the resin composition can be improved. The cross-sectional shape of the carbon fiber is preferably a circular cross-section, but may be a rectangular, oval, or other irregular cross-section as necessary.

The content of the carbon fiber having a tensile strength of 4000 to 4800MPa is preferably 1 to 60% by mass, and more preferably 1 to 50% by mass in view of improving the mechanical strength. Among them, it is more preferably 15 to 50% by mass in view of a lower density and a larger effect of improving mechanical strength than those of conventional resin compositions. When the content of the carbon fibers in the polyamide resin composition is more than 60% by mass, the effect of improving mechanical properties is saturated, and not only a further improvement effect cannot be achieved, but also the fluidity is extremely low, and it may be difficult to obtain a molded article.

The polyamide resin composition of the present invention may further contain additives such as a stabilizer, a colorant, an antistatic agent, a flame retardant aid, and a carbonization inhibitor, as required. Examples of the colorant include pigments such as titanium oxide, zinc oxide, and carbon black, and dyes such as aniline black. Examples of the stabilizer include hindered phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, light stabilizers, heat stabilizers composed of copper compounds, and heat stabilizers composed of alcohols. Examples of the flame retardant include a bromine-based flame retardant, a phosphorus-based flame retardant composed of a metal phosphonate, and a flame retardant composed of a phosphazene compound. Examples of the flame retardant aid include metal salts such as zinc stannate, zinc borate, antimony trioxide, antimony pentoxide, and sodium antimonate. The carbonization inhibitor is an additive for improving tracking resistance, and examples thereof include inorganic substances such as metal hydroxides and metal borates.

The polyamide resin composition of the present invention has a creep strain amount of 2.0% or less, preferably 1.5% or less, and more preferably 1.0% or less, when 100 hours pass under the measurement conditions of a temperature of 100 ℃ and a tensile load of 75 MPa. When the strain amount of the polyamide resin composition is more than 2.0%, the rotational speed of a rotary member such as an impeller or a fan to be obtained may be limited. When the polyamide resin composition of the present invention contains the semi-aromatic polyamide (a) and the fibrous reinforcing material (B), the strain amount can be set to 2.0% or less.

The polyamide resin composition of the present invention has a flexural strength measured according to ISO 178 of preferably 180MPa or more, more preferably 250MPa or more, and a flexural modulus measured according to ISO 178 of preferably 5GPa or more, more preferably 10GPa or more. When the flexural strength of the polyamide resin composition is 180MPa or more and the flexural modulus is 5GPa or more, dimensional changes of a rotating body such as an impeller or a fan to be obtained become small, and the polyamide resin composition can be rotated at a higher speed.

As a method for producing the polyamide resin composition of the present invention, a method of blending the semi-aromatic polyamide (a), the fibrous reinforcing material (B), and additives and the like added as necessary and melt-kneading them is preferable.

Examples of the melt-kneading method include a method using a batch kneader such as Brabender (Brabender), a banbury mixer, a Henschel mixer, a screw rotor, a roll, a uniaxial extruder, a biaxial extruder, and the like.

Examples of the method for processing the polyamide resin composition into various shapes include: a method of extruding the molten mixture into a strip shape to form a pellet shape, a method of thermally cutting or underwater cutting the molten mixture to form a pellet shape, a method of extruding into a sheet shape to cut it, and a method of extruding into a block shape to pulverize it to form a powder particle shape.

The molded article of the present invention is obtained by molding the polyamide resin composition, and can be used for a rotating body such as an impeller or a fan.

In general, the impeller is housed in the housing, and a flow is generated in a space between an outer surface of the impeller and an inner surface of the housing when the impeller rotates, and the flow is generated faster as the rotation of the impeller is faster and the space is smaller.

On the other hand, the impeller rotating at a high speed receives a large stress (centrifugal force) in a centrifugal direction in proportion to the mass, and further receives a bending stress in a direction opposite to the rotation due to the resistance of the fluid, so that the impeller is constantly and minutely deformed during the rotation. When the impeller is rotated at a high speed for a long time, the impeller is gradually deformed in the centrifugal direction. The degree of continuous deformation can be evaluated by creep deformation of the material of the impeller. The degree of instantaneous deformation can be evaluated by the modulus of elasticity of the material of the impeller.

In order to obtain high performance, the impeller is designed to reduce the clearance formed by the dimensional difference between the outer diameter of the impeller and the inner diameter of the housing and to rotate faster, and therefore, the smaller the density, the higher the elastic modulus, and the smaller the creep deformation of the material constituting the high performance impeller are, the more preferable. The polyamide resin composition of the present invention has high heat resistance and high creep strength, and therefore can be suitably used as a rotor such as a propeller, an impeller, a fan, an axial fan, a blade, or a runner, or a sliding member such as an actuator or a bearing. Particularly, the rotor is preferably used for a rotor used when the rotor is small in size, has thin blades, and rotates at high speed 1 ten thousand times per 1 minute or more.

Examples of the method for producing a molded article by molding a polyamide resin composition include injection molding, extrusion molding, blow molding, and sintering molding. Among them, injection molding is preferable in view of the great effect of improving mechanical properties and moldability.

The injection molding machine is not particularly limited, and examples thereof include a coaxial screw injection molding machine and a ram injection molding machine. The polyamide resin composition heated and melted in the cylinder of the injection molding machine is measured for each injection, injected into a mold in a molten state, cooled and solidified in a predetermined shape to form a molded article, and taken out from the mold. The resin temperature at the time of injection molding is preferably not lower than the melting point (Tm) of the semi-aromatic polyamide (a), and more preferably lower than (Tm +50 ℃).

The mold temperature during molding is not particularly limited, but is preferably 80 to 150 ℃. The polyamide resin composition of the present invention can be used to obtain a molded article having high crystallinity using a mold in the temperature range, and further, can obtain a molded article having high heat resistance and excellent low water absorption.

In the conventional resin used as a material for an impeller capable of rotating at a high speed, the mold temperature at the time of molding must be 200 ℃ or higher. The polyamide resin composition of the present invention can be molded using a low-temperature mold as compared with conventional resins, and can reduce energy costs in the production of molded articles.

In the case of heating and melting the resin composition, it is preferable to use resin composition pellets that have been sufficiently dried. If the amount of water contained is large, the resin composition foams in the cylinder of the injection molding machine, and it is difficult to obtain an optimum molded article. The water content of the resin composition pellets used for injection molding is preferably less than 0.3% by mass, more preferably less than 0.1% by mass.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Measurement method

The properties of the polyamide resin composition and the molded article were measured and evaluated by the following methods.

(1) Melting Point

The temperature was raised to 360 ℃ at a temperature raising rate of 20 ℃/min by using a differential scanning calorimeter (model DSC-7 manufactured by Perkin Elmer Co., Ltd.), then the temperature was maintained at 360 ℃ for 5 minutes, at a temperature lowering rate of 20 ℃/min to 25 ℃, then the temperature was maintained at 25 ℃ for 5 minutes, and then the temperature was again raised at a temperature raising rate of 20 ℃/min and measured, and the peak of the endothermic peak at this time was taken as the melting point.

(2) Density of

The pellets of the resin composition thus obtained were sufficiently dried, and then injection-molded by an injection molding machine (model S2000i-100B, manufactured by FANUC) under conditions of a cylinder temperature (melting point +15 ℃) and a molding cycle of 35 seconds to prepare a dumbbell test piece. In examples 1 to 12 and comparative examples 1 to 10 and 12, the mold temperature was set to 120 ℃ and in comparative example 11, the mold temperature was set to 90 ℃.

The resulting dumbbell test pieces were used, and the density was measured according to ISO 1183.

(3) Mechanical characteristics

The dumbbell test pieces prepared by the same method as described in (2) above were used, and the flexural strength and flexural modulus were measured according to ISO 178.

Further, using the prepared dumbbell test piece, a tensile creep test under a tensile load of 75MPa was carried out in a temperature environment of 100 ℃ with reference to ISO899-1, and the creep strain amount after 100 hours was measured.

(4) Appearance (arithmetic mean height)

After the pellets of the obtained resin composition were sufficiently dried, a test piece of 40mm × 40mm × 3.0mmt was prepared by using an injection molding machine (J35-AD, manufactured by Nippon Steel works Co., Ltd.) under conditions of a cylinder temperature (melting point +15 ℃), a mold surface roughness (arithmetic average height (Sa)) of 1 μm, a mold temperature of 180 ℃, and a molding cycle of 30 seconds.

Similarly, test pieces were prepared at a mold temperature of 120 ℃.

The arithmetic mean height (Sa) was measured at a magnification of 12 times in the range of 25 mm. times.25 mm at the center of the test piece using a 3D shape measuring apparatus (VR-3200, manufactured by Keyence).

In the present invention, the arithmetic mean height (Sa) is 5 μm or less.

(5) Fluidity of the resin

After the pellets of the obtained resin composition were sufficiently dried, a test piece for measuring a flow length was prepared to have a thickness of 0.5mm by using an injection molding machine (J35-AD, manufactured by Nippon Steel works Co., Ltd.) under conditions of a cylinder temperature (melting point +15 ℃ C.), a mold temperature of 120 ℃ C., and a molding cycle of 30 seconds.

In the present invention, the flow length is preferably 8mm or more, and the flow length is preferably 15mm or more.

(6) Productivity of production

In the examples, the extrusion amount (Q/Ns) per 1 rotation of the screw was kept constant and the discharge amount (Q) was increased so as to increase the torque rise of the extruder or the fluctuation of the torque until melt kneading became difficult under the melt kneading conditions (screw rotation speed (Ns)250rpm and discharge amount (Q)25kg/h) in the production of the resin composition pellets, and the upper limit of the producible discharge amount (Q) was determined as the maximum discharge amount. The higher the maximum discharge amount of the polyamide resin composition, the easier the kneading becomes, and the higher the productivity and the production efficiency become.

(7) Continuous endurance test

An impeller having a maximum outer diameter of 25mm was produced by the molding method described in (2) above, except that a mold for molding the impeller of fig. 1 was used instead of the mold for producing the dumbbell test piece.

The obtained impeller was housed in a casing having a clearance of 500 μm formed by a dimensional difference between the outer diameter of the impeller and the inner diameter of the casing, and a continuous durability test was performed at a rotation speed of 100000rpm for 200 hours using a rotation tester, and the continuous durability of the impeller was evaluated from the time until the impeller was broken due to cracks introduced into the impeller by the contact between the impeller and the casing due to fatigue, creep life, and deformation of the blade portion of the impeller, or due to a defect of the impeller.

(8) Contact test of blade

Using a rotational tester, the clearance formed by the difference in size between the outer diameter of the impeller and the inner diameter of the rotational tester was set to 2 types of 500 μm and 100 μm, and 5 impellers manufactured in the same manner as in (7) were rotated at 120000rpm for 1 minute, respectively, to measure the ratio of the number of impellers damaged by cracks introduced into the impeller due to contact of the blade portions or by the impeller defect.

2. Raw materials

The raw materials used in the examples and comparative examples are as follows.

(1) Polyamide

Semi-aromatic polyamide (PA10T-1)

4.81kg of powdery terephthalic acid (TPA) as a dicarboxylic acid component, 0.15kg of stearic acid (STA) as a monocarboxylic acid component, and 9.3g of sodium hypophosphite monohydrate as a polymerization catalyst were placed in a reaction apparatus of a ribbon mixer type, and heated to 170 ℃ while stirring at 30rpm under a nitrogen seal. Then, 5.04kg of 1, 10-decamethylenediamine (DDA) heated to 100 ℃ as a diamine component was continuously added over 2.5 hours (continuous injection method) using an injection apparatus while keeping the temperature at 170 ℃ and the rotation speed at 30rpm, to obtain a reaction product. The molar ratio of the raw material monomers is TPA: DDA: STA 49.3: 49.8: 0.9 (equivalent ratio of functional groups of starting monomers TPA: DDA: STA ═ 49.5: 50.0: 0.5).

Then, the obtained reaction product was polymerized by heating at 250 ℃ and 30rpm for 8 hours in a nitrogen stream in the same reaction apparatus to prepare a polyamide powder.

Then, the obtained polyamide powder was formed into a strand using a biaxial kneader, the strand was cooled and solidified in a water tank, and the strand was cut by a pelletizer to obtain a pellet of a semi-aromatic polyamide (PA 10T-1).

Semi-aromatic polyamides (PA10T-2, PA10T/10I-1, 2, 3, PA10T/6T-1, 2, PA9T-1, 2, 3, 4)

Semi-aromatic polyamide particles were obtained in the same manner as PA10T-1, except that the resin composition was changed as shown in table 1.

The resin composition and the characteristic values of the obtained semi-aromatic polyamide are shown in table 1.

[ Table 1]

TPA: terephthalic acid, IPA: isophthalic acid

DDA 1, 10-decamethylenediamine, NDA 1, 9-nonanediamine, HDA 1, 6-hexanediamine

2M-ODA 2-methyl-1, 8-octanediamine, STA stearic acid, BA benzoic acid

PA 66: polyamide 66 (UNITIKANylon 66A125J, U.S. A. K.K.) having a melting point of 260 DEG C

(2)PEEK

Polyetheretherketone (VESTAKEEP 2000G manufactured by Daicel Evonik corporation) having a melting point of 340 DEG C

(3) Fibrous reinforcing material

CF 1: carbon fiber (T800 SC-24K, Toray corporation) having a tensile strength of 5880MPa

CF 2: tensile strength of carbon fiber (MITSUBISHI RAYON CO., TR06NEB4J, LTD.) of 4900MPa

CF 3: carbon fiber (MITSUISHI RAYON CO., LTD. TR06NLB5K) tensile strength 4120MPa

CF 4: carbon fiber (Teijin Carbon Tenax Co., Ltd., HTA-C6-NR) tensile strength of 3920MPa

CF 5: carbon fiber (MITSUISHI RAYON CO., LTD. 223HE) tensile strength of 3800MPa

GF: glass fiber (T-262H manufactured by Nippon Denshoku Co., Ltd.) having tensile strength of 3200MPa

Example 1

A weight-loss continuous quantitative feeder (CE-W-1, manufactured by Kubota corporation) was used to measure 90 parts by mass of PA10T-1, and the measured material was fed to a main feed port of a co-rotating twin-screw extruder (TEM 26SS, manufactured by Toshiba Machine Co., Ltd.) having a screw diameter of 26mm and an L/D50, and melt-kneaded. In the middle, 10 parts by mass of CF3 was supplied from a side inlet, and further melt-kneaded. After being drawn into a strand form from a die, the strand was cooled and solidified in a water tank, and the strand was cut with a pelletizer to obtain pellets of the resin composition. The cylinder temperature of the extruder was set to (melting point of PA 10T-1-5 to +15 ℃), the screw rotation speed was set to 250rpm, and the discharge rate was set to 25 kg/h.

Examples 2 to 12 and comparative examples 1 to 12

Pellets of a resin composition were obtained in the same manner as in example 1, except that the composition of the resin composition was changed as shown in table 2.

The resin composition and evaluation of the obtained resin composition are shown in table 2.

[ Table 2]

The polyamide resin compositions of examples 1 to 12 had a creep strain amount of 2.0% or less because the constituent components were within the ranges specified in the present invention, and the surface roughness (arithmetic average height (Sa)) of the molded articles molded at a mold temperature of 120 ℃ and 180 ℃ was small, and the appearance was excellent.

The polyamide resin compositions of examples 11 and 12 had slightly poor fluidity because the tensile strength of the carbon fibers was high. The polyamide resin compositions of examples 1 and 2 have a small content of the fibrous reinforcing material, and the polyamide resin compositions of examples 6 to 10 have a small melting point and low heat resistance of the semi-aromatic polyamide resin, and therefore have a slightly large creep strain amount.

Since the resin compositions of examples 3 and 9 contain the semi-aromatic polyamide (a) in which the monocarboxylic acid component is stearic acid, the flow lengths thereof were longer than those of the resin compositions of examples 5 to 10 in which the monocarboxylic acid component of the semi-aromatic polyamide (a) is benzoic acid.

The resin composition of comparative example 1 contains no fibrous reinforcing material, the resin compositions of comparative examples 2 and 3 use carbon fibers having a tensile strength of less than 4000MPa, and the resin compositions of comparative examples 4 and 5 use glass fibers instead of carbon fibers, and therefore, the creep strain amounts are large.

In comparative example 6, since the content of the fibrous reinforcing material was too large, melt kneading could not be performed, and a resin composition could not be obtained.

The resin compositions of comparative examples 7 to 11 used polyamide resins having a low melting point, and therefore had a large creep strain amount. The resin composition of comparative example 12, which used polyetheretherketone, had a high density, and the surface roughness (Sa) of the molded article molded with a low-temperature mold was large, resulting in poor appearance.

In the continuous durability test, the impeller molded from the resin composition obtained in the comparative example was broken up to 50 hours, but the impeller molded from the resin composition of the example had a lifetime of 100 hours or more. Since the influence of heat generation is reduced when the load is not continuous and a strain recovery effect can be expected, the durability of the impeller can be said to be sufficient if the impeller has a lifetime of 100 hours or more in the continuous durability test. The impeller of examples 3 to 5, 11 and 12 can be changed from 500 μm to 100 μm in clearance with the casing, and the compressor using the impeller can improve the compression efficiency.