CN110964316A

CN110964316A - Polyamide composition, molded article, and semi-aromatic polyamide

Info

Publication number: CN110964316A
Application number: CN201910903804.5A
Authority: CN
Inventors: 家田真次; 永濑康一; 三上纯; 梅村亮介
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp
Priority date: 2018-10-01
Filing date: 2019-09-24
Publication date: 2020-04-07
Anticipated expiration: 2039-09-24
Also published as: JP7195850B2; CN110964316B; JP2020055940A

Abstract

The present invention relates to a polyamide composition, a molded article, and a semi-aromatic polyamide. The present invention provides a polyamide composition having excellent fluidity and surface appearance while maintaining good water absorption rigidity and thermal rigidity. A polyamide composition comprising 50 to 99 parts by mass of (A) an aliphatic polyamide comprising a diamine and a dicarboxylic acid, and 1 to 50 parts by mass of (B) a semi-aromatic polyamide; the semi-aromatic polyamide (B) contains dicarboxylic acid units containing at least 75 mol% of isophthalic acid units and diamine units containing at least 50 mol% of diamine units having 4 to 10 carbon atoms, wherein the amount of terminal-capped ends, expressed in the form of 1g of equivalents relative to at least one polyamide selected from the group consisting of the aliphatic polyamide (A) and the semi-aromatic polyamide (B), is 5 to 180 microequivalents/g, and the peak temperature of tan delta of the polyamide composition is 90 ℃ or higher.

Description

Polyamide composition, molded article, and semi-aromatic polyamide

Technical Field

The present invention relates to a polyamide composition, a molded article, and a semi-aromatic polyamide.

Background

Polyamides typified by polyamide 6 (hereinafter also referred to as "PA 6") and polyamide 66 (hereinafter also referred to as "PA 66") are excellent in molding processability, mechanical properties, and chemical resistance, and therefore are widely used as various part materials for automobiles, electric and electronic products, industrial materials, daily products, household products, and the like.

In recent years, the use environment of polyamide resins has become thermally and mechanically severe, and polyamide resin materials having improved mechanical properties, particularly rigidity after water absorption and rigidity under high-temperature use, and having little change in physical properties when used in all environments have been demanded.

In order to improve productivity, molded articles obtained using polyamide resins are sometimes molded under high cycle molding conditions in which the molding temperature is increased or the mold temperature is decreased.

On the other hand, when molding is performed under high temperature conditions, there is a problem that a molded article cannot be stably obtained in some cases due to decomposition of the polyamide resin or change in fluidity.

In particular, polyamide resins excellent in stability of surface appearance of molded articles even under severe molding conditions as described above are required.

In order to satisfy such a demand, a polyamide containing polyamide 66/6I having an isophthalic acid component incorporated therein is disclosed as a material capable of improving the surface appearance and mechanical properties of a molded article (for example, patent document 1). Further, as a material capable of improving mechanical properties, fluidity, surface appearance and the like, a polyamide composition containing polyamide 6T/6I into which a terephthalic acid component and an isophthalic acid component are introduced is disclosed (for example, see patent documents 2 and 3).

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 6-32980

Patent document 2: japanese patent laid-open publication No. 2000-154316

Patent document 3: japanese patent laid-open publication No. 11-349806

Patent document 4: japanese examined patent publication (Kokoku) No. 3-059019

Patent document 5: japanese examined patent publication (Kokoku) No. 4-013300

Patent document 6: japanese examined patent publication (Kokoku) No. 4-032775

Disclosure of Invention

Problems to be solved by the invention

However, although the techniques disclosed in patent documents 1 and 3 improve the rigidity under normal use conditions, there is room for improvement in the rigidity after water absorption and the rigidity under high-temperature use.

In addition, the polyamide produced by the production technique disclosed in patent document 2 has improved rigidity after water absorption and rigidity in use at high temperatures. However, although the surface appearance of the molded article under ordinary molding conditions is improved, there is a problem that the appearance and stability of the surface of the molded article are deteriorated under severe molding conditions such as high cycle molding conditions.

As can be seen, the prior art actually does not know a polyamide copolymer which is excellent in rigidity after water absorption and rigidity in use at high temperatures and which shows little change in physical properties in use under all environments. Further, it is difficult to suppress the decrease in rigidity after water absorption and under high-temperature use while maintaining the balance between mechanical strength and rigidity which are characteristics of the polyamide copolymer, and a composition and a molded article comprising a polyamide copolymer or a polyamide having such physical properties are required.

The present invention has been made in view of the above circumstances, and provides a polyamide composition having excellent fluidity and surface appearance while maintaining good rigidity at the time of water absorption (hereinafter referred to as water absorption rigidity) and rigidity at the time of use at high temperature (hereinafter referred to as thermal rigidity), and a molded article comprising the polyamide composition.

Means for solving the problems

That is, the present invention includes the following aspects.

The polyamide composition of the first aspect of the present invention contains 50 parts by mass or more and 99 parts by mass or less of (a) an aliphatic polyamide containing a diamine and a dicarboxylic acid, and 1 part by mass or more and 50 parts by mass or less of (B) a semi-aromatic polyamide containing a dicarboxylic acid unit containing at least 75 mol% of an isophthalic acid unit and a diamine unit containing at least 50 mol% of a diamine unit having 4 or more and 10 or less carbon atoms, wherein the amount of a terminal-terminated end represented by an equivalent of 1g or more relative to at least one polyamide selected from the group consisting of the (a) aliphatic polyamide and the (B) semi-aromatic polyamide is 5 micro equivalents/g or more and 180 micro equivalents/g or less, the polyamide composition has a tan delta peak temperature of 90 ℃ or higher.

The amount of the terminal end capped with acetic acid represented by an equivalent to 1g of the semi-aromatic polyamide (B) may be 5 to 180 microequivalents/g.

The polyamide composition may have a weight average molecular weight Mw of 15000 or more and 35000 or less.

The polyamide composition may have a molecular weight distribution Mw/Mn of 2.6 or less.

The total of the amount of the amino terminal and the amount of the carboxyl terminal, which is expressed as an equivalent to 1g of the polyamide in the polyamide composition, may be 70 to 145 microequivalents per g.

The ratio of the amount of the amino terminal to the total amount of the amino terminal and the amount of the carboxyl terminal { amino terminal amount/(amino terminal amount + carboxyl terminal amount) } may be 0.25 or more and less than 0.4.

The (a) aliphatic polyamide may be polyamide 66 or polyamide 610.

In the (B) semi-aromatic polyamide, the content of the isophthalic acid unit may be 100 mol% with respect to the total amount of the dicarboxylic acid units.

The (B) semi-aromatic polyamide may be polyamide 6I.

The weight average molecular weight mw (B) of the semi-aromatic polyamide (B) may be 10000 or more and 25000 or less.

The molecular weight distribution mw (B)/mn (B) of the semi-aromatic polyamide (B) may be 2.4 or less.

The difference { mw (a) -mw (B) } between the weight average molecular weight mw (a) of the aliphatic polyamide (a) and the weight average molecular weight mw (B) of the semi-aromatic polyamide (B) may be 10000 or more.

The polyamide composition may further contain at least one metal salt selected from the group consisting of a metal salt of phosphorous acid and a metal salt of hypophosphorous acid.

The polyamide composition may further contain a phosphite compound.

The polyamide composition may further contain 5 parts by mass or more and 250 parts by mass or less of (C) an inorganic filler, based on 100 parts by mass of the total of the aliphatic polyamide (a) and the semi-aromatic polyamide (B).

The molded article according to the second aspect of the present invention is obtained by molding the polyamide composition according to the first aspect, and has a surface gloss value of 50 or more.

A semi-aromatic polyamide according to a third aspect of the present invention comprises a dicarboxylic acid unit containing at least 75 mol% of an isophthalic acid unit and a diamine unit containing a chain aliphatic diamine having 4 to 10 carbon atoms, wherein the amount of a terminal-blocked end represented by an equivalent to 1g of the semi-aromatic polyamide is 5 to 180 microequivalents/g, and the peak temperature of tan δ of the semi-aromatic polyamide is 90 ℃.

The amount of the acetic acid-terminated end represented by an equivalent to 1g of the semi-aromatic polyamide may be 5 to 180 microequivalents/g.

The total of the amino terminal amount and the carboxyl terminal amount represented by an equivalent to 1g of the semi-aromatic polyamide may be 50 to 155 microequivalents/g.

The semi-aromatic polyamide may have a weight average molecular weight Mw of 10000 or more and 35000 or less.

The semi-aromatic polyamide may have a molecular weight distribution Mw/Mn of 2.6 or less.

Effects of the invention

According to the polyamide composition and the semi-aromatic polyamide of the above embodiment, a molded article having excellent fluidity and surface appearance while maintaining good water absorption rigidity and thermal rigidity can be obtained. The molded article of the present embodiment has excellent fluidity and surface appearance while maintaining good water absorption rigidity and thermal rigidity.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, simply referred to as "the present embodiment") will be described in detail. The following embodiments are illustrative of the present invention, and are not intended to limit the present invention to the following. The present invention can be implemented with appropriate modifications within the scope of the gist of the present invention.

In the present specification, the term "polyamide" refers to a polymer having an amide (-NHCO-) group in the main chain.

Polyamide composition

The polyamide composition of the present embodiment contains 50 parts by mass or more and 99 parts by mass or less of (a) an aliphatic polyamide and 1 part by mass or more and 50 parts by mass or less of (B) a semi-aromatic polyamide. (A) The aliphatic polyamide comprises a diamine and a dicarboxylic acid. (B) The semi-aromatic polyamide comprises a dicarboxylic acid unit containing at least 75 mol% of an isophthalic acid unit and a diamine unit containing at least 50 mol% of a diamine unit having 4 to 10 carbon atoms.

In the polyamide composition of the present embodiment, the amount of the terminal-blocked end represented by an equivalent of 1g to at least one polyamide selected from the group consisting of (a) an aliphatic polyamide and (B) a semi-aromatic polyamide is 5 to 180 microequivalents/g.

The peak temperature of tan δ of the polyamide composition of the present embodiment is 90 ℃ or higher.

The polyamide composition of the present embodiment having the above-described structure can provide a molded article having excellent water absorption rigidity, thermal rigidity, fluidity, and surface appearance.

The semi-aromatic polyamide of the present embodiment contains a dicarboxylic acid unit containing at least 75 mol% of an isophthalic acid unit and a diamine unit containing a chain aliphatic diamine having 4 to 10 carbon atoms.

In the semi-aromatic polyamide of the present embodiment, the amount of the terminal-blocked end represented by an equivalent to 1g of the semi-aromatic polyamide is 5 to 180 microequivalents/g.

The semi-aromatic polyamide of the present embodiment has a tan δ peak temperature of 90 ℃ or higher.

By having the above-described configuration, the semi-aromatic polyamide according to the present embodiment can provide a molded article having excellent fluidity, surface appearance, and corrosion resistance while maintaining good water absorption rigidity and thermal rigidity.

As the semi-aromatic polyamide, the semi-aromatic polyamide (B) described later can be used.

The semi-aromatic polyamide of the present embodiment may be prepared as a semi-aromatic polyamide composition by including an inorganic filler, an additive, and the like, which will be described later. The semi-aromatic polyamide composition preferably contains 90% or more of the semi-aromatic polyamide.

< Properties of Polyamide composition >

The molecular weight, melting point Tm2, crystallization enthalpy Δ H, tan δ peak temperature, capped end amount, amino end amount, and carboxyl end amount of the polyamide composition obtained by the production method of the present embodiment can be set to the following configurations, and can be measured by the methods described in the examples described later.

[ molecular weight of Polyamide composition ]

As an index of the molecular weight of the polyamide composition, a weight average molecular weight (Mw) can be used. The weight average molecular weight (Mw) of the polyamide composition is preferably 15000 or more and 35000 or less, more preferably 17000 or more and 35000 or less, still more preferably 20000 or more and 35000 or less, still more preferably 22000 or more and 34000 or less, particularly preferably 24000 or more and 33000 or less, and most preferably 25000 or more and 32000 or less.

When the weight average molecular weight (Mw) is within the above range, a polyamide composition having more excellent mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, corrosion resistance, and the like can be obtained. In addition, the polyamide composition containing a component represented by an inorganic filler is more excellent in surface appearance.

As a method for controlling the Mw of the polyamide composition within the above range, there can be mentioned a method using (a) an aliphatic polyamide and (B) a semi-aromatic polyamide having a weight average molecular weight within the above range.

The Mw can be measured by Gel Permeation Chromatography (GPC) as described in the following examples.

[ Total content of polyamides having a number average molecular weight Mn of 500 to 2000 in the entire polyamides in the polyamide composition ]

The total content of the polyamides having a number average molecular weight Mn of 500 or more and 2000 or less in the entire polyamides in the polyamide composition is preferably 0.5% by mass or more and less than 2.5% by mass, more preferably 0.5% by mass or more and 2.0% by mass or less, further preferably 0.5% by mass or more and 1.5% by mass or less, particularly preferably 0.5% by mass or more and 1.0% by mass or less, and most preferably 0.6% by mass or more and 0.9% by mass or less, relative to the total mass of the polyamides in the polyamide composition.

When the total content of the polyamides having a number average molecular weight Mn of 500 or more and 2000 or less in all the polyamides in the polyamide composition is not less than the lower limit value, the fluidity tends to be more excellent and the surface appearance of a molded article obtained from the polyamide composition containing a component represented by (C) an inorganic filler tends to be more excellent. When the total content is less than the upper limit, gas generation during molding tends to be more effectively suppressed.

In order to control the total content of the polyamides having a number average molecular weight Mn of 500 or more and 2000 or less in the entire polyamides in the polyamide composition within the above range, the amount of the terminal-capped end represented by an equivalent of 1g with respect to the (B) semi-aromatic polyamide is important, and it is preferable to control the amount of the terminal-capped end to be 5 micro equivalents/g or more and 180 micro equivalents/g or less. The weight average molecular weight (mw (B)) of the semi-aromatic polyamide (B) is also important, and it is preferable to control mw (B) to 10000 to 25000.

The total content of polyamides having a number average molecular weight Mn of 500 or more and 2000 or less in the total polyamides in the polyamide composition can be determined from an elution curve under the measurement conditions in the examples described below by using GPC.

In addition, in the GPC measurement, when the composition containing the aliphatic polyamide (a) and the semi-aromatic polyamide (B) contains other components soluble in the solvent in which the polyamide is dissolved, the other components may be extracted and removed using a solvent in which the polyamide is not soluble but the other components are soluble, and then the GPC measurement may be performed. Further, the (C) inorganic filler or the like insoluble in the solvent for dissolving the polyamide may be dissolved in the solvent for dissolving the polyamide composition, and then insoluble matter may be removed by filtration, followed by GPC measurement.

(A) the difference between the weight average molecular weight Mw of the aliphatic polyamide (A) and the weight average molecular weight Mw of the semi-aromatic polyamide (B) ((A) -Mw (B) })

(A) The difference { mw (a) -mw (B) } between the weight average molecular weight mw (a) of the aliphatic polyamide and the weight average molecular weight mw (B) of the semi-aromatic polyamide (B) is preferably 2000 or more, more preferably 5000 or more, further preferably 8000 or more, particularly preferably 10000 or more, and most preferably 12000 or more.

When { mw (a) -mw (B) } is not less than the lower limit value, the composition having more excellent water absorption rigidity and thermal rigidity can be obtained by forming domains from the semi-aromatic polyamide (B).

[ molecular weight distribution of Polyamide composition ]

The molecular weight distribution of the polyamide composition of the present embodiment is indicated by weight average molecular weight (Mw)/number average molecular weight (Mn).

The lower limit of the weight average molecular weight (Mw)/number average molecular weight (Mn) of the polyamide composition of the present embodiment is preferably 1.0, more preferably 1.7, still more preferably 1.8, and particularly preferably 1.9.

On the other hand, the upper limit value of Mw/Mn of the polyamide composition of the present embodiment is preferably 2.6, more preferably 2.4, still more preferably 2.3, particularly preferably 2.2, and most preferably 2.1.

That is, the Mw/Mn of the polyamide composition of the present embodiment is preferably 1.0 or more and 2.6 or less, more preferably 1.0 or more and 2.4 or less, further preferably 1.7 or more and 2.4 or less, further preferably 1.8 or more and 2.3 or less, particularly preferably 1.9 or more and 2.2 or less, and most preferably 1.9 or more and 2.1 or less.

When the Mw/Mn is within the above range, a polyamide composition having more excellent flowability and the like tends to be obtained. Further, molded articles obtained from a polyamide composition containing a component represented by (C) an inorganic filler tend to have more excellent surface appearance.

Examples of the method for controlling the weight average molecular weight (Mw)/number average molecular weight (Mn) of the polyamide composition to fall within the above-mentioned range include a method for adjusting the weight average molecular weight (Mw), (B)/number average molecular weight (Mn (B)) of the semi-aromatic polyamide (B) to fall within the below-mentioned range.

When the polyamide composition contains an aromatic compound unit in its molecular structure, the molecular weight distribution (Mw/Mn) tends to increase with the increase in molecular weight. When the molecular weight distribution is within the above range, the proportion of polyamide molecules having a three-dimensional structure can be further reduced, and the three-dimensional structure of the molecules can be more appropriately prevented during high-temperature processing, so that more favorable fluidity can be maintained. This tends to improve the surface appearance of a molded article obtained from a polyamide composition containing a component represented by the inorganic filler (C).

The weight average molecular weight (Mw)/number average molecular weight (Mn) of the polyamide composition can be calculated using the weight average molecular weight (Mw) and the number average molecular weight (Mn) obtained by GPC as shown in examples described later.

[ melting Point Tm2 of Polyamide composition ]

The melting point Tm2 of the polyamide composition is preferably 200 ℃ or more, more preferably 220 ℃ or more and 270 ℃ or less, still more preferably 230 ℃ or more and 265 ℃ or less, particularly preferably 240 ℃ or more and 260 ℃ or less, and most preferably 250 ℃ or more and 260 ℃ or less.

When the melting point Tm2 of the polyamide composition is not less than the lower limit value, a polyamide composition having more excellent thermal rigidity and the like tends to be obtained.

On the other hand, when the melting point Tm2 of the polyamide composition is not more than the above upper limit, the polyamide composition tends to be more inhibited from thermal decomposition or the like during melt processing such as extrusion or molding.

[ enthalpy of crystallization of Polyamide composition Δ H ]

From the viewpoint of mechanical properties, particularly water absorption rigidity and thermal rigidity, the polyamide composition preferably has a crystallization enthalpy Δ H of 10J/g or more, more preferably 14J/g or more, still more preferably 18J/g or more, and particularly preferably 20J/g or more. On the other hand, the upper limit value of the crystallization enthalpy Δ H is not particularly limited, and is preferably higher.

As a method for controlling the crystallization enthalpy Δ H of the polyamide composition within the above range, for example, a method for controlling the contents of the (a) aliphatic polyamide and the (B) semi-aromatic polyamide within the following range, and the like can be mentioned.

Examples of the apparatus for measuring the melting point Tm2 and the crystallization enthalpy Δ H of the polyamide composition include Diamond-DSC manufactured by perkin elmer.

[ tan delta Peak temperature of Polyamide composition ]

The lower limit of the peak temperature of tan δ of the polyamide composition is 90 ℃, preferably 100 ℃, more preferably 110 ℃, and still more preferably 120 ℃. On the other hand, the upper limit of the tan δ peak temperature of the resin composition is preferably 150 ℃, more preferably 140 ℃, and still more preferably 130 ℃.

That is, the resin composition has a tan δ peak temperature of 90 ℃ or more, preferably 100 ℃ or more and 150 ℃ or less, more preferably 110 ℃ or more and 140 ℃ or less, and still more preferably 120 ℃ or more and 130 ℃ or less.

When the peak temperature of tan δ of the polyamide composition is not less than the lower limit, the polyamide composition tends to have more excellent water absorption rigidity and thermal rigidity. On the other hand, when the peak temperature of tan δ of the polyamide composition is not more than the above upper limit, the surface appearance of a molded article obtained from a polyamide composition containing a component represented by a filler tends to be more excellent.

Examples of the method for controlling the tan δ peak temperature of the polyamide composition within the above range include a method in which the contents of the aliphatic polyamide (a) and the semi-aromatic polyamide (B) are controlled within the ranges described below.

[ crystallization Peak temperature Tc obtained when the Polyamide composition was cooled at 20 ℃/min ]

The crystallization peak temperature Tc (° c) obtained when the polyamide composition is cooled at 20 ℃/min is preferably 160 ℃ or more and 240 ℃ or less, more preferably 170 ℃ or more and 230 ℃ or less, further preferably 180 ℃ or more and 225 ℃ or less, particularly preferably 190 ℃ or more and 220 ℃ or less, and most preferably 200 ℃ or more and 215 ℃.

When the crystallization peak temperature Tc (. degree.C.) of the polyamide composition is not less than the lower limit value, a polyamide composition having more excellent mold release properties during molding can be obtained.

On the other hand, when the crystallization peak temperature Tc (C) of the polyamide composition is not more than the above upper limit, the molded article obtained from the polyamide composition containing the component represented by the (C) inorganic filler is more excellent in surface appearance.

The crystallization peak temperature Tc of the polyamide composition of the present embodiment can be measured according to JIS-K7121 by the method described in the examples described later.

Examples of the device for measuring the crystallization peak temperature Tc include Diamond-DSC manufactured by Perkin Elmer, Inc.

As a method for controlling the crystallization peak temperature Tc of the polyamide composition within the above range, for example, a method of controlling the contents of (a) the aliphatic polyamide and (B) the semi-aromatic polyamide within the above range, and the like can be cited.

[ amount of terminal-capped end in Polyamide composition ]

The amount of the terminal-blocked end in the polyamide composition is preferably 5 to 180 microequivalents/g, more preferably 10 to 170 microequivalents/g, still more preferably 20 to 160 microequivalents/g, particularly preferably 30 to 140 microequivalents/g, and most preferably 40 to 140 microequivalents/g, based on 1g of polyamide. When the amount of the terminal group to be capped is within the above range, a composition excellent in MD (mold deposit), surface appearance and heat strength at the time of molding can be obtained. The amount of capped ends can be determined by NMR.

[ Total amount of amino terminal and carboxyl terminal of Polyamide composition ]

The total amount of the amino terminal amount and the carboxyl terminal amount of the polyamide composition is preferably 70 to 145 microequivalents/g, more preferably 80 to 140 microequivalents/g, still more preferably 90 to 130 microequivalents/g, and particularly preferably 100 to 120 microequivalents/g, based on 1g of the semi-aromatic polyamide (B).

When the total amount of the amino terminal amount and the carboxyl terminal amount of the polyamide composition is within the above range, a polyamide composition having more excellent flowability and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

[ ratio of the amount of amino terminal to the total amount of the amount of amino terminal and the amount of carboxyl terminal in the polyamide composition ]

The ratio of the amino terminal amount to the total amount of the amino terminal amount and the carboxyl terminal amount { amino terminal amount/(amino terminal amount + carboxyl terminal amount) } of the polyamide composition is preferably 0.25 or more and less than 0.4, more preferably 0.35 or more and less than 0.4, and still more preferably 0.25 or more and less than 0.35. When the ratio of the amount of the amino terminal to the total amount of the amino terminal and the amount of the carboxyl terminal is not less than the lower limit value, corrosion of an extruder or a molding machine can be more effectively suppressed. On the other hand, when the ratio of the amount of the amino terminal to the total amount of the amino terminal and the amount of the carboxyl terminal is less than the above upper limit, a composition having excellent discoloration resistance to heat or light can be obtained.

The polyamide composition of the present embodiment having the above-described structure can form a molded article having excellent water absorption rigidity, thermal rigidity, fluidity, and corrosion resistance, and having excellent surface appearance.

Hereinafter, the respective constituent components of the polyamide composition of the present embodiment will be described in detail.

Hereinafter, each constituent component included in the polyamide composition of the present embodiment will be described.

[ aliphatic Polyamide ] of (A)

The aliphatic polyamide (a) contained in the polyamide composition of the present embodiment contains (a-a) aliphatic dicarboxylic acid units and (a-b) aliphatic diamine units.

[ (A-a) aliphatic dicarboxylic acid Unit ]

The aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit is not limited to the following, and examples thereof include: linear or branched saturated aliphatic dicarboxylic acids having 3 to 20 carbon atoms such as malonic acid, dimethylmalonic acid, succinic acid, 2-dimethylsuccinic acid, 2, 3-dimethylglutaric acid, 2-diethylsuccinic acid, 2, 3-diethylglutaric acid, glutaric acid, 2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid, and diglycolic acid.

The reason why the aliphatic dicarboxylic acid unit (a-a) preferably contains an aliphatic dicarboxylic acid having 6 to 20 carbon atoms is that the polyamide composition tends to be more excellent in heat resistance, flowability, toughness, low water absorption, rigidity, and the like. The aliphatic dicarboxylic acid unit having 6 to 20 carbon atoms is not particularly limited, and examples thereof include: adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid, etc. Among them, adipic acid, sebacic acid, or dodecanedioic acid is preferable from the viewpoint of heat resistance of the polyamide composition and the like.

The aliphatic dicarboxylic acid constituting the aliphatic dicarboxylic acid unit (A-a) may be used alone or in combination of two or more.

The aliphatic polyamide (a) may further contain a unit derived from a trivalent or more polycarboxylic acid such as trimellitic acid, trimesic acid, or pyromellitic acid, as necessary. The trivalent or higher polycarboxylic acid may be used alone or in combination of two or more.

[ (A-b) aliphatic diamine units ]

The aliphatic diamine constituting the aliphatic diamine unit (A-b) may be a straight chain or a branched chain.

The linear aliphatic diamine constituting the aliphatic diamine unit is not limited to the following, and examples thereof include: and linear saturated aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamylenediamine, dodecamethylenediamine, and tridecylenediamine.

The diamine constituting the diamine unit having a substituent branched from the main chain is not limited to the following, and examples thereof include: branched saturated aliphatic diamines having 3 to 20 carbon atoms such as 2-methylpentamethylenediamine (also referred to as 2-methyl-1, 5-diaminopentane), 2, 4-trimethylhexamethylenediamine, 2,4, 4-trimethylhexamethylenediamine, 2-methyl-1, 8-octanediamine (also referred to as 2-methyloctamethylenediamine), and 2, 4-dimethyloctamethylenediamine.

Among them, 2-methylpentamethylenediamine or 2-methyl-1, 8-octanediamine is preferable, and 2-methylpentamethylenediamine is more preferable. The inclusion of such an aliphatic diamine tends to provide a polyamide composition having more excellent heat resistance, rigidity, and the like.

The number of carbon atoms of the aliphatic diamine unit (a-b) is preferably 6 to 12, more preferably 6 to 10. When the number of carbon atoms is not less than the lower limit, the heat resistance is more excellent, while when the number of carbon atoms is not more than the upper limit, the crystallinity and the mold release property are more excellent.

The aliphatic diamine (a-b) may further contain a trihydric or higher polyvalent aliphatic amine such as bis-hexamethyltriamine, if necessary.

The diamine may be used alone or in combination of two or more.

Specific examples of the aliphatic polyamide (a) used in the polyamide composition of the present embodiment include: polyamide 66(PA66), polyamide 46(PA46), polyamide 610(PA 610). PA66 is excellent in heat resistance, moldability, and toughness, and is therefore considered to be a material suitable for automobile parts. Long-chain aliphatic polyamides such as PA610 are excellent in chemical resistance.

In the polyamide composition of the present embodiment, the blending amount of the (a) aliphatic polyamide is 50.0 parts by mass or more and 99.0 parts by mass or less, preferably 52.5 parts by mass or more and 95.0 parts by mass or less, more preferably 54.0 parts by mass or more and 90.0 parts by mass or less, further preferably 55.0 parts by mass or more and 85.0 parts by mass or less, further preferably 56.0 parts by mass or more and 80.0 parts by mass or less, particularly preferably 57.0 parts by mass or more and 77.5 parts by mass or less, and most preferably 57.5 parts by mass or more and 75.5 parts by mass or less, with respect to 100 parts by mass of the total amount of the polyamide in the polyamide composition.

By setting the blending amount of the aliphatic polyamide (a) within the above range, a polyamide composition excellent in mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, corrosion resistance and the like can be obtained. In addition, polyamide compositions containing components represented by inorganic fillers have excellent surface appearance.

< (B) semi-aromatic polyamide

The semi-aromatic polyamide (B) contained in the polyamide composition of the present embodiment is a polyamide containing a dicarboxylic acid unit (B-a) containing at least 75 mol% of an isophthalic acid unit and a diamine unit (B-B) containing at least 50 mol% of a diamine unit having 4 to 10 carbon atoms.

The total amount of the isophthalic acid unit and the diamine unit having 4 to 10 carbon atoms is preferably 80 to 100 mol%, more preferably 90 to 100 mol%, and still more preferably 100 mol% based on the total amount of all the constituent units of the semi-aromatic polyamide (B).

In the present invention, the ratio of the predetermined monomer unit constituting the semi-aromatic polyamide (B) can be measured by nuclear magnetic resonance spectroscopy (NMR) or the like.

[ (B-a) dicarboxylic acid Unit ]

In the dicarboxylic acid unit (B-a), the content of the isophthalic acid unit is 75 mol% or more, preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and still more preferably 100 mol% based on the total amount of dicarboxylic acids.

When the content of the isophthalic acid unit relative to the total number of moles of the dicarboxylic acid is not less than the lower limit, a polyamide composition satisfying mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, surface appearance, corrosion resistance, and the like can be obtained at the same time.

The dicarboxylic acid unit (B-a) may contain an aromatic dicarboxylic acid unit, an aliphatic dicarboxylic acid unit, or an alicyclic dicarboxylic acid unit in addition to the isophthalic acid unit.

(aromatic dicarboxylic acid unit)

The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid unit other than the isophthalic acid unit is not limited to the following, and examples thereof include: dicarboxylic acids having phenyl group and naphthyl group. The aromatic group of the aromatic dicarboxylic acid may be unsubstituted or may have a substituent.

The substituent is not particularly limited, and examples thereof include: an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, a halogen group such as a chloro group or a bromo group, a silyl group having 1 to 6 carbon atoms, a sulfonic acid group, and salts thereof (such as sodium salt).

Specifically, the following substances are not limited, and may be mentioned: and aromatic dicarboxylic acids having 8 to 20 carbon atoms, which are unsubstituted or substituted with a predetermined substituent, such as terephthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, and 5-sodium sulfoisophthalate. Among them, terephthalic acid is preferred.

The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid unit may be used alone or in combination of two or more.

(aliphatic dicarboxylic acid unit)

(alicyclic dicarboxylic acid Unit)

The alicyclic dicarboxylic acid constituting the alicyclic dicarboxylic acid unit (hereinafter also referred to as "alicyclic dicarboxylic acid unit") is not limited to the following, and examples thereof include: the alicyclic structure is an alicyclic dicarboxylic acid having 3 to 10 carbon atoms, and preferably an alicyclic dicarboxylic acid having 5 to 10 carbon atoms.

Such alicyclic dicarboxylic acids are not limited to the following, and examples thereof include: 1, 4-cyclohexanedicarboxylic acid, 1, 3-cyclopentanedicarboxylic acid and the like. Among them, 1, 4-cyclohexanedicarboxylic acid is preferable.

The alicyclic dicarboxylic acid constituting the alicyclic dicarboxylic acid unit may be used alone or in combination of two or more.

The alicyclic group of the alicyclic dicarboxylic acid may be unsubstituted or substituted. The substituents are not limited to the following groups, and examples thereof include: and an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

The dicarboxylic acid unit other than the isophthalic acid unit preferably includes an aromatic dicarboxylic acid unit, and more preferably includes an aromatic dicarboxylic acid unit having 6 to 12 carbon atoms.

By using such a dicarboxylic acid, the polyamide composition tends to have more excellent mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, surface appearance, corrosion resistance, and the like.

In the polyamide composition of the present embodiment, the dicarboxylic acid constituting the dicarboxylic acid unit (B-a) is not limited to the compound described as the dicarboxylic acid, and may be a compound equivalent to the dicarboxylic acid.

Here, the "compound equivalent to a dicarboxylic acid" refers to a compound capable of forming a dicarboxylic acid structure similar to the dicarboxylic acid structure derived from the dicarboxylic acid. Such a compound is not limited to the following compounds, and examples thereof include dicarboxylic acid anhydrides and acid halides.

The semi-aromatic polyamide (B) may further contain units derived from a trivalent or higher polycarboxylic acid such as trimellitic acid, trimesic acid, and pyromellitic acid, if necessary.

The trivalent or higher polycarboxylic acid may be used alone or in combination of two or more.

[ (B-B) diamine units ]

The diamine unit (B-B) constituting the semi-aromatic polyamide (B) contains at least 50 mol% of a diamine unit having 4 to 10 carbon atoms. The following are not limited, and examples thereof include: aliphatic diamine units, alicyclic diamine units, aromatic diamine units, and the like.

(aliphatic diamine Unit)

The aliphatic diamine constituting the aliphatic diamine unit is not limited to the following, and examples thereof include: and linear saturated aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamylenediamine, dodecamethylenediamine, and tridecylenediamine.

(alicyclic diamine Unit)

The alicyclic diamine (hereinafter, also referred to as "alicyclic diamine") constituting the alicyclic diamine unit is not limited to the following, and examples thereof include: 1, 4-cyclohexanediamine, 1, 3-cyclopentanediamine, and the like.

(aromatic diamine Unit)

Examples of the aromatic diamine constituting the aromatic diamine unit include: m-xylylenediamine, and the like.

Among these, an aliphatic diamine unit is preferable, a diamine unit having a linear saturated aliphatic group having 4 to 10 carbon atoms is more preferable, a diamine unit having a linear saturated aliphatic group having 6 to 10 carbon atoms is further preferable, and a hexamethylenediamine unit is particularly preferable.

By using such a diamine, a polyamide composition having more excellent mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, surface appearance, corrosion resistance, and the like, tends to be obtained.

The diamine may be used alone or in combination of two or more.

The semi-aromatic polyamide (B) is preferably polyamide 6I (polyhexamethylene isophthalamide), polyamide 9I (polynonamethylene isophthalamide) or polyamide 10I (polydecamethylene isophthalamide), and particularly preferably polyamide 6I.

The semi-aromatic polyamide (B) may further contain a ternary or higher aliphatic polyamine such as bis-hexamethyltriamine, if necessary.

The tertiary or higher aliphatic polyamine may be used alone or in combination of two or more.

In the polyamide composition of the present embodiment, the blending amount of the (B) semi-aromatic polyamide is 1.0 part by mass or more and 50.0 parts by mass or less, preferably 5.0 parts by mass or more and 47.5 parts by mass or less, more preferably 10.0 parts by mass or more and 46.0 parts by mass or less, further preferably 15.0 parts by mass or more and 45.0 parts by mass or less, further preferably 20.0 parts by mass or more and 44.0 parts by mass or less, particularly preferably 22.5 parts by mass or more and 43.0 parts by mass or less, and most preferably 24.5 parts by mass or more and 42.5 parts by mass or less, relative to 100 parts by mass of the amount of the entire polyamide in the polyamide composition. By setting the blending amount of the semi-aromatic polyamide (B) within the above range, a polyamide composition excellent in mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, corrosion resistance and the like can be obtained. In addition, polyamide compositions containing components represented by inorganic fillers have excellent surface appearance.

[ at least one unit selected from the group consisting of a lactam unit and an aminocarboxylic acid unit ]

(A) The aliphatic polyamide and (B) the semi-aromatic polyamide may further contain at least one unit selected from the group consisting of a lactam unit and an aminocarboxylic acid unit. By including such a unit, a polyamide having further excellent toughness tends to be obtained. Here, the lactam and the aminocarboxylic acid constituting the lactam unit and the aminocarboxylic acid unit mean a lactam and an aminocarboxylic acid capable of polymerization (condensation).

The lactam and the aminocarboxylic acid constituting the lactam unit and the aminocarboxylic acid unit are not limited to those described below, and for example, a lactam and an aminocarboxylic acid having 4 to 14 carbon atoms are preferable, and a lactam and an aminocarboxylic acid having 6 to 12 carbon atoms are more preferable.

The lactam constituting the lactam unit is not limited to the following, and examples thereof include: butyrolactams, valerolactams, epsilon-caprolactams, caprylolactams, enantholactams, undecanolactams, laurolactams, and the like.

Among them, as the lactam, epsilon-caprolactam or lauryllactam is preferable, and epsilon-caprolactam is more preferable. The inclusion of such a lactam tends to provide a polyamide composition having more excellent toughness.

The aminocarboxylic acid constituting the aminocarboxylic acid unit is not limited to, but examples thereof include an ω -aminocarboxylic acid, α, an ω -amino acid, and the like, which are compounds obtained by ring-opening a lactam.

The aminocarboxylic acid is preferably a linear or branched saturated aliphatic carboxylic acid having 4 to 14 carbon atoms and being substituted with an amino group at the ω -position. Such aminocarboxylic acids are not limited to the following, and examples thereof include: 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and the like. In addition, as the aminocarboxylic acid, there can be also mentioned: p-aminomethylbenzoic acid, and the like.

The lactam and the aminocarboxylic acid constituting the lactam unit and the aminocarboxylic acid unit may be used alone or in combination of two or more.

The total ratio (mol%) of the lactam unit and the aminocarboxylic acid unit is preferably 0 mol% or more and 20 mol% or less, more preferably 0 mol% or more and 10 mol% or less, and still more preferably 0 mol% or more and 5 mol% or less, based on the whole polyamide.

When the total ratio of the lactam unit and the aminocarboxylic acid unit is within the above range, an effect such as improvement in fluidity tends to be obtained.

< end-capping agent >

At least one polyamide selected from the group consisting of (a) aliphatic polyamides and (B) semi-aromatic polyamides contained in the polyamide composition of the present embodiment has a terminal end capped with a terminal-capping agent.

Such an end-capping agent may be added as a molecular weight modifier in the production of a polyamide from the dicarboxylic acid and diamine, and optionally at least one compound selected from the group consisting of lactams and aminocarboxylic acids.

The blocking agent is not limited to the following, and examples thereof include: monocarboxylic acids, monoamines, anhydrides, monoisocyanates, monoacyl halides, monoesters, monoalcohols, and the like. Examples of the acid anhydride include: phthalic anhydride, and the like.

Among them, monocarboxylic acids or monoamines are preferred. The polyamide composition having more excellent thermal stability tends to be obtained by terminating the ends of the polyamide with a terminating agent.

The blocking agent may be used alone or in combination of two or more.

The monocarboxylic acid that can be used as the end-capping agent may be any monocarboxylic acid that has reactivity with an amino group that may be present at the terminal of the polyamide. Specific examples of the monocarboxylic acid include, but are not limited to, the following: aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, aromatic monocarboxylic acids, and the like.

The aliphatic monocarboxylic acid is not limited to the following, and examples thereof include: formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutyric acid, and the like.

The alicyclic monocarboxylic acid is not limited to the following, and examples thereof include: cyclohexane carboxylic acid, and the like.

The aromatic monocarboxylic acid is not limited to benzoic acid, methylbenzoic acid, α -naphthoic acid, β -naphthoic acid, methylnaphthoic acid, phenylacetic acid, and the like.

These monocarboxylic acids may be used alone or in combination of two or more.

The monoamine that can be used as the end-capping agent may be any monoamine that has reactivity with a carboxyl group that may be present at the end of the polyamide. Specific examples of the monoamine include, but are not limited to, the following: aliphatic monoamines, alicyclic monoamines, aromatic monoamines, and the like.

The aliphatic amine is not limited to the following, and examples thereof include: methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine and the like.

The alicyclic amine is not limited to the following, and examples thereof include: cyclohexylamine, dicyclohexylamine, and the like.

The aromatic amine is not limited to the following, and examples thereof include: aniline, toluidine, diphenylamine, naphthylamine, and the like.

These monoamines may be used alone or in combination of two or more.

Polyamide compositions containing polyamides end-capped with end-capping agents tend to have excellent heat resistance, flowability, toughness, low water absorption, rigidity, and corrosion resistance.

< method for producing polyamide >

In obtaining each polyamide, the amount of dicarboxylic acid added and the amount of diamine added are preferably about equimolar amounts. In view of the escape of the diamine to the outside of the reaction system during the polymerization reaction, the molar amount of the total diamine is preferably 0.9 or more and 1.2 or less, more preferably 0.95 or more and 1.1 or less, and still more preferably 0.98 or more and 1.05 or less, relative to the molar amount of the total dicarboxylic acid of 1.

The method for producing a polyamide is not limited to the following method, and includes, for example, the following polymerization step (1) or (2).

(1) And a step of polymerizing a combination of a dicarboxylic acid constituting a dicarboxylic acid unit and a diamine constituting a diamine unit to obtain a polymer.

(2) And a step of polymerizing at least one selected from the group consisting of lactams which constitute lactam units and aminocarboxylic acids which constitute aminocarboxylic acid units to obtain a polymer.

In addition, the method for producing a polyamide preferably further comprises an increasing step of increasing the polymerization degree of the polyamide after the polymerization step. Further, a capping step of capping the end of the obtained polymer with a capping agent may be included after the polymerization step and the raising step as necessary.

Specific examples of the method for producing the polyamide include the following various methods 1) to 4).

1) A method of heating an aqueous solution or an aqueous suspension of one or more selected from the group consisting of dicarboxylic acid-diamine salt, a mixture of dicarboxylic acid and diamine, lactam, and aminocarboxylic acid, and polymerizing while maintaining the molten state (hereinafter, sometimes referred to as "hot-melt polymerization method").

2) A method of increasing the degree of polymerization of a polyamide obtained by a hot-melt polymerization method while maintaining the solid state at a temperature not higher than the melting point (hereinafter, sometimes referred to as "hot-melt polymerization/solid-phase polymerization method").

3) A method of polymerizing one or more selected from the group consisting of dicarboxylic acid-diamine salts, a mixture of dicarboxylic acids and diamines, lactams, and aminocarboxylic acids while maintaining a solid state (hereinafter, may be referred to as "solid-phase polymerization method").

4) A method of polymerizing a dicarboxylic acid halide component equivalent to a dicarboxylic acid and a diamine component (hereinafter, may be referred to as "solution method").

Among these, a specific production method of polyamide preferably includes a hot melt polymerization method. In the case of producing a polyamide by a hot-melt polymerization method, it is preferable to maintain the molten state until the polymerization is completed. In order to maintain the molten state, it is necessary to produce the polyamide under polymerization conditions suitable for the polyamide. The polymerization conditions include, for example, the following conditions. First, the polymerization pressure in the hot melt polymerization method was controlled to 14kg/cm²Above 25kg/cm²Thereafter (gauge pressure), heating was continued. Then, the pressure in the tank was reduced for 30 minutes or more until the pressure in the tank reached the atmospheric pressure (gauge pressure: 0 kg/cm)²)。

In the method for producing a polyamide, the polymerization system is not particularly limited, and may be a batch system or a continuous system.

The polymerization apparatus used for producing the polyamide is not particularly limited, and a known apparatus can be used. Specific examples of the polymerization apparatus include: autoclave type reactors, drum type reactors, extruder type reactors (kneaders and the like), and the like.

Hereinafter, a method for producing a polyamide by a batch hot melt polymerization method will be specifically described as a method for producing a polyamide, but the method for producing a polyamide is not limited thereto.

First, an aqueous solution of raw material components (a combination of a dicarboxylic acid and a diamine, and if necessary, at least one selected from the group consisting of lactams and aminocarboxylic acids) containing a polyamide in an amount of about 40 mass% to about 60 mass% is prepared. Then, the aqueous solution is concentrated to about 65 mass% or more and about 90 mass% or less in a concentration tank operated at a temperature of 110 ℃ or more and 180 ℃ or less and a pressure of about 0.035MPa or more and about 0.6MPa or less (gauge pressure), thereby obtaining a concentrated solution.

Next, the obtained concentrated solution was transferred to an autoclave, and heating was continued until the pressure in the autoclave reached about 1.2MPa or more and about 2.2MPa or less (gauge pressure).

Next, in the autoclave, while at least one of water and a gas component is extracted, the pressure is maintained at about 1.2MPa or more and about 2.2MPa or less (gauge pressure). Then, when the temperature reached about 220 ℃ or higher and about 260 ℃ or lower, the pressure was reduced to the atmospheric pressure (gauge pressure of 0 MPa). By reducing the pressure in the autoclave to atmospheric pressure and then reducing the pressure as necessary, water by-produced can be efficiently removed.

Next, the autoclave is pressurized with an inert gas such as nitrogen gas, and the polyamide melt is extruded from the autoclave in the form of a strand. The extruded strand was cooled and cut to obtain polyamide pellets.

< Polymer end of Polyamide >

The polymer terminal of the polyamide ((a) aliphatic polyamide and (B) semi-aromatic polyamide) contained in the polyamide composition of the present embodiment is not particularly limited, and may be classified and defined as 1) to 4 below.

Namely, 1) an amino terminal, 2) a carboxyl terminal, 3) a terminal formed by a capping agent, and 4) other terminals.

1) The amino terminal is an amino group (-NH)₂Radical) derived from a diamine.

2) The carboxyl terminus is the polymer terminus having a carboxyl group (-COOH group) derived from a dicarboxylic acid.

3) The end formed by the end-capping agent is an end formed when the end-capping agent is added at the time of polymerization. The blocking agent may be a blocking agent described later.

4) The other terminal is a terminal of the polymer not classified into 1) to 3) above. Specific examples of the other terminal include: a terminal formed by deamination at the amino terminus, a terminal formed by decarboxylation at the carboxyl terminus, and the like.

< Property of Polyamide >

[ (A) Properties of aliphatic Polyamide ]

(A) The molecular weight, the amount of the end-capped end, the melting point Tm2, the enthalpy of crystallization Δ H, and the tan δ peak temperature of the aliphatic polyamide can be set to the following configurations, and specifically, can be measured by the methods shown below.

((A) weight-average molecular weight Mw (A) of aliphatic Polyamide)

As an index of the molecular weight of the aliphatic polyamide (a), a weight average molecular weight can be used. (A) The weight average molecular weight (mw (a)) of the aliphatic polyamide is preferably 10000 or more and 50000 or less, more preferably 15000 or more and 45000 or less, further preferably 20000 or more and 40000 or less, and particularly preferably 25000 or more and 35000 or less.

When mw (a) is within the above range, a polyamide composition satisfying mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, corrosion resistance, and the like, at the same time tends to be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

The weight average molecular weight (mw (a)) of the aliphatic polyamide (a) can be measured by GPC.

(A) molecular weight distribution of aliphatic Polyamide)

(A) The molecular weight distribution of the aliphatic polyamide is indicated by (a) the weight average molecular weight of the aliphatic polyamide (mw), (a)/(a) the number average molecular weight of the aliphatic polyamide (mn (a)).

Mw (A)/Mn (A) is preferably 1.0 or more, more preferably 1.8 or more and 2.2 or less, and further preferably 1.9 or more and 2.1 or less.

With Mw (A)/Mn (A) within the above range, a polyamide composition having excellent flowability and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

Examples of the method for controlling Mw (A)/Mn (A) within the above-mentioned range include the methods shown in the following 1) and 2).

1) A method of adding a known polycondensation catalyst such as phosphoric acid or sodium hypophosphite as an additive in the thermal fusion polymerization of polyamide.

2) A method in which polymerization conditions such as heating conditions and reduced pressure conditions are controlled in addition to the method 1).

Mw (A)/Mn (A) can be calculated by using Mw (A) and Mn (A) obtained by GPC.

(A) amount of terminal end of aliphatic Polyamide

The amount of the terminal end of the (a) aliphatic polyamide is preferably 5 to 180 microequivalents per gram, more preferably 5 to 150 microequivalents per gram, still more preferably 10 to 100 microequivalents per gram, particularly preferably 15 to 80 microequivalents per gram, and most preferably 20 to 60 microequivalents per gram, based on 1 gram of the (a) aliphatic polyamide. When the amount of the terminal group to be capped is within the above range, a composition excellent in MD, surface appearance and heat strength at the time of molding can be obtained. The amount of the blocked terminal can be measured by NMR.

((A) melting Point Tm2 of aliphatic Polyamide)

(A) The lower limit of the melting point Tm2 of the aliphatic polyamide is preferably 220 ℃, more preferably 230 ℃, and still more preferably 240 ℃. On the other hand, the upper limit of the melting point Tm2 of the aliphatic polyamide (a) is preferably 300 ℃, more preferably 290 ℃, still more preferably 280 ℃, and particularly preferably 270 ℃.

That is, the melting point Tm2 of the aliphatic polyamide (a) is preferably 220 ℃ to 300 ℃, more preferably 230 ℃ to 290 ℃, still more preferably 240 ℃ to 280 ℃, and particularly preferably 240 ℃ to 270 ℃.

When the melting point Tm2 of the aliphatic polyamide (a) is not less than the lower limit, the molded article obtained from the polyamide composition tends to be more excellent in thermal rigidity and the like. On the other hand, when the melting point Tm2 of the aliphatic polyamide (a) is not more than the upper limit, the polyamide composition tends to be more inhibited from thermal decomposition or the like during melt processing such as extrusion or molding.

(A) enthalpy of crystallization Δ H of aliphatic Polyamide)

The lower limit value of the crystallization enthalpy Δ H of the aliphatic polyamide (a) is preferably 30J/g, more preferably 40J/g, still more preferably 50J/g, and particularly preferably 60J/g, from the viewpoint of mechanical properties, particularly water absorption rigidity and thermal rigidity. On the other hand, the upper limit value of the crystallization enthalpy Δ H of the aliphatic polyamide (a) is not particularly limited, and is preferably higher.

Examples of the device for measuring the melting point Tm2 and the crystallization enthalpy Δ H of the aliphatic polyamide (a) include Diamond-DSC manufactured by perkin elmer.

((A) tan delta Peak temperature of aliphatic Polyamide)

(A) The peak temperature of tan δ of the aliphatic polyamide is preferably 40 ℃ or more, more preferably 50 ℃ or more and 110 ℃ or less, further preferably 60 ℃ or more and 100 ℃ or less, particularly preferably 70 ℃ or more and 95 ℃ or less, and most preferably 80 ℃ or more and 90 ℃ or less.

When the tan δ peak temperature of the aliphatic polyamide (a) is not less than the lower limit, the molded article obtained from the polyamide composition tends to have more excellent water absorption rigidity and thermal rigidity.

(A) The tan δ peak temperature of the aliphatic polyamide can be measured using a viscoelasticity measurement analyzer (DVE-V4 manufactured by rhelogy).

[ (B) Properties of semi-aromatic Polyamide ]

(B) The molecular weight, melting point Tm2, crystallization enthalpy Δ H, tan δ peak temperature, end amount of end capped, amino end amount, and carboxyl end amount of the semi-aromatic polyamide can be set to the following configurations, and specifically, can be measured by the methods shown below.

(B) weight-average molecular weight Mw of semi-aromatic Polyamide (B)

As an index of the molecular weight of the semi-aromatic polyamide (B), the weight average molecular weight (mw (B)) of the semi-aromatic polyamide (B) can be used.

(B) The weight average molecular weight (mw (b)) of the semi-aromatic polyamide is preferably 10000 or more and 35000 or less, more preferably 10000 or more and 25000 or less, further preferably 13000 or more and 24000 or less, further preferably 15000 or more and 23000 or less, particularly preferably 18000 or more and 22000 or less, and most preferably 19000 or more and 21000 or less.

When the weight average molecular weight (mw (B)) of the semi-aromatic polyamide (B) is within the above range, a polyamide composition having more excellent mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

The weight average molecular weight (mw (B)) of the semi-aromatic polyamide (B) can be measured by GPC.

(B) molecular weight distribution of semi-aromatic Polyamide)

(B) The molecular weight distribution of the semi-aromatic polyamide is indicated by the weight average molecular weight (mw (B))/(B) the number average molecular weight (mn (B)) of the semi-aromatic polyamide.

Mw (b)/mn (b) is preferably 1.0 or more and 2.6 or less, more preferably 1.0 or more and 2.4 or less, further preferably 1.7 or more and 2.4 or less, further preferably 1.8 or more and 2.3 or less, particularly preferably 1.9 or more and 2.2 or less, and most preferably 1.9 or more and 2.1 or less.

With Mw (B)/Mn (B) within the above range, a polyamide composition having more excellent flowability and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

Examples of the method for controlling Mw (B)/Mn (B) within the above-mentioned range include the methods shown in the following 1) and 2).

2) A method in which the polycondensation reaction is completed at as low a temperature as possible and in a short time by controlling the polymerization conditions such as heating conditions and reduced pressure conditions in addition to the method 1).

In particular, if the semi-aromatic polyamide (B) is an amorphous polyamide, the reaction temperature can be reduced because the polyamide does not have a melting point, which is preferable.

When the polyamide contains an aromatic compound unit in its molecular structure, the molecular weight distribution (Mw/Mn) tends to increase with the increase in molecular weight. A high molecular weight distribution indicates a high proportion of polyamide molecules having a three-dimensional structure. Therefore, by controlling mw (b)/mn (b) within the above range, a polyamide composition which suppresses the progress of three-dimensional structure of molecules during high-temperature processing and has more excellent fluidity and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

The Mw (B)/Mn (B) can be calculated by using Mw (B) and Mn (B) obtained by GPC.

(B) enthalpy of crystallization of semi-aromatic Polyamide Δ H)

The crystallization enthalpy Δ H of the semi-aromatic polyamide (B) is preferably 15J/g or less, more preferably 10J/g or less, even more preferably 5J/g or less, and particularly preferably 0J/g, from the viewpoint of mechanical properties, particularly water absorption rigidity and thermal rigidity.

As a method for controlling the crystallization enthalpy Δ H of the semi-aromatic polyamide (B) within the above range, a known method for reducing the crystallinity of the polyamide can be employed, and is not particularly limited. As a known method for reducing the crystallinity of polyamide, specifically, for example, there are mentioned: a method of increasing the ratio of meta-substituted aromatic dicarboxylic acid units relative to dicarboxylic acid units, and a method of increasing the ratio of meta-substituted aromatic diamine units relative to diamine units. From this viewpoint, it is important that the (B) semi-aromatic polyamide contains 75 mol% or more of isophthalic acid units as (B-a) dicarboxylic acid units in the total dicarboxylic acid units constituting the (B) semi-aromatic polyamide, and it is particularly preferable that the (B) semi-aromatic polyamide contains 100 mol% of isophthalic acid units.

Examples of the device for measuring the crystallization enthalpy Δ H of the semi-aromatic polyamide (B) include Diamond-DSC manufactured by perkin elmer.

((B) tan. delta. Peak temperature of semi-aromatic Polyamide)

(B) The peak temperature of tan δ of the semi-aromatic polyamide is preferably 90 ℃ or more, more preferably 100 ℃ or more and 160 ℃ or less, further preferably 110 ℃ or more and 150 ℃ or less, particularly preferably 120 ℃ or more and 145 ℃ or less, and most preferably 130 ℃ or more and 140 ℃ or less.

When the semi-aromatic polyamide (B) has a tan δ peak temperature of not less than the lower limit, a polyamide composition having more excellent water absorption rigidity and thermal rigidity tends to be obtained. When the semi-aromatic polyamide (B) has a tan δ peak temperature of not more than the upper limit, a molded article obtained from a polyamide composition containing a component represented by an inorganic filler is more excellent in surface appearance.

As a method for controlling the tan δ peak temperature of the semi-aromatic polyamide (B) within the above range, for example, a method of increasing the ratio of the aromatic monomer to the dicarboxylic acid unit, and the like can be cited. From this viewpoint, it is important that the (B) semi-aromatic polyamide contains 75 mol% or more of isophthalic acid units as (B-a) dicarboxylic acid units in the total dicarboxylic acid units constituting the (B) semi-aromatic polyamide, and it is particularly preferable that the (B) semi-aromatic polyamide contains 100 mol% of isophthalic acid units.

(B) The tan δ peak temperature of the semi-aromatic polyamide can be measured, for example, using a viscoelasticity measurement analyzer (DVE-V4 manufactured by rhelogy).

(B) end-capped terminal amount of semi-aromatic polyamide)

The amount of the terminal-blocked end of the (B) semi-aromatic polyamide is preferably 5 to 180 microequivalents/g, more preferably 10 to 170 microequivalents/g, still more preferably 30 to 160 microequivalents/g, particularly preferably 50 to 160 microequivalents/g, and most preferably 60 to 160 microequivalents/g, relative to 1g of the (B) semi-aromatic polyamide. When the amount of the terminal group to be capped is within the above range, a composition excellent in MD, surface appearance and heat strength at the time of molding can be obtained. In addition, it is particularly preferable that the amount of the terminal group blocked with acetic acid is within the above range. The amount of the blocked terminal can be measured by NMR.

(B) amino terminal amount of semi-aromatic polyamide)

The amount of the amino terminal of the (B) semi-aromatic polyamide is preferably 5 to 90 microequivalents/g, more preferably 10 to 80 microequivalents/g, still more preferably 10 to 70 microequivalents/g, particularly preferably 20 to 60 microequivalents/g, and most preferably 30 to 50 microequivalents/g, relative to 1g of the (B) semi-aromatic polyamide.

When the amount of the amino terminal of the semi-aromatic polyamide (B) is within the above range, a polyamide composition which is more excellent in terms of preventing discoloration by heat or light can be obtained.

The amount of the amino terminal can be measured by NMR.

(B) carboxyl end amount of semi-aromatic polyamide)

The amount of the carboxyl terminal of the (B) semi-aromatic polyamide is preferably 20 to 150 microequivalents/g, more preferably 30 to 120 microequivalents/g, still more preferably 30 to 100 microequivalents/g, particularly preferably 40 to 90 microequivalents/g, and most preferably 50 to 80 microequivalents/g, relative to 1g of the (B) semi-aromatic polyamide.

When the amount of the carboxyl terminal of the semi-aromatic polyamide (B) is within the above range, a polyamide composition having more excellent flowability and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

The amount of the carboxyl terminal can be measured by NMR.

(B) the total amount of amino terminal and carboxyl terminal of the semi-aromatic polyamide)

The total amount of the amino terminal amount and the carboxyl terminal amount of the (B) semi-aromatic polyamide is preferably 50 to 155 microequivalents/g, more preferably 60 to 150 microequivalents/g, even more preferably 70 to 140 microequivalents/g, particularly preferably 80 to 130 microequivalents/g, and most preferably 90 to 120 microequivalents/g, relative to 1g of the (B) semi-aromatic polyamide.

When the total amount of the amino terminal amount and the carboxyl terminal amount of the semi-aromatic polyamide (B) is within the above range, a polyamide composition having more excellent flowability and the like can be obtained. Further, molded articles obtained from polyamide compositions containing components typified by inorganic fillers have more excellent surface appearance.

< other ingredients >

The polyamide composition of the present embodiment may contain, in addition to the above-described (a) aliphatic polyamide and (B) semi-aromatic polyamide, one or more components selected from the group consisting of (C) an inorganic filler, (D) a nucleating agent, (E) a lubricant, (F) a heat stabilizer, (G) another polymer, (H) at least one metal salt selected from the group consisting of a metal salt of phosphorous acid and a metal salt of hypophosphorous acid, (J) a phosphite compound, and (K) another additive.

[ (C) inorganic Filler Material ]

The inorganic filler (C) is not limited to the following, and examples thereof include: glass fibers, carbon fibers, calcium silicate fibers, potassium titanate fibers, aluminum borate fibers, clay, flaky glass, talc, kaolin, mica, hydrotalcite, calcium carbonate, magnesium carbonate, zinc oxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, titanium oxide, silicon oxide, magnesium oxide, calcium silicate, sodium aluminosilicate, magnesium silicate, ketjen black, acetylene black, furnace black, carbon nanotubes, graphite, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, montmorillonite, swellable fluoromica, apatite, and the like. These (C) inorganic fillers may be used alone or in combination of two or more.

Among them, from the viewpoint of further improving the mechanical strength, one or more selected from the group consisting of glass fibers, carbon fibers, wollastonite, kaolin, mica, talc, calcium carbonate, magnesium carbonate, potassium titanate fibers, aluminum borate fibers and clay are preferable. Among these, more preferred is at least one selected from the group consisting of glass fibers, carbon fibers, wollastonite, kaolin, mica, talc, calcium carbonate and clay.

When the inorganic filler (C) is glass fiber or carbon fiber, the number average fiber diameter (d) is preferably 3 μm or more and 30 μm or less, more preferably 3 μm or more and 20 μm or less, further preferably 3 μm or more and 12 μm or less, particularly preferably 3 μm or more and 9 μm or less, and most preferably 4 μm or more and 6 μm or less.

By setting the number average fiber diameter to the upper limit or less, a polyamide composition having further excellent toughness and surface appearance of a molded article can be obtained. On the other hand, by setting the number average fiber diameter to the lower limit or more, a polyamide composition having a more excellent balance between the physical properties (flowability and the like) in terms of cost and handling of powder can be obtained. Further, by setting the number average fiber diameter to 3 μm or more and 9 μm or less, a polyamide composition having more excellent vibration fatigue characteristics and sliding properties can be obtained.

When the inorganic filler (C) is glass fiber or carbon fiber, the cross section thereof may be circular or flat. The flat cross section is not limited to the following shape, and examples thereof include: oblong, approximately oblong, elliptical, and cocoon-shaped with a thinned lengthwise central portion. The term "flattening" as used herein means a value represented by d2/d1 (a perfectly circular flattening of about 1) where the major diameter of the cross section of the fiber is d2 and the minor diameter of the cross section of the fiber is d 1.

When the inorganic filler (C) is glass fiber or carbon fiber, among them, from the viewpoint of being able to impart excellent mechanical strength to the polyamide composition, it is preferable that the number average fiber diameter (d) is 3 μm or more and 30 μm or less, the weight average fiber length (l) is 100 μm or more and 750 μm or less, and the aspect ratio (l/d), which is the ratio of the weight average fiber length (l) to the number average fiber diameter (d), is 10 or more and 100 or less. The "number average fiber diameter (d)" herein is an average value of the major axis (d2 described above) of the cross section of the fiber, and can be obtained by the calculation method described below.

From the viewpoint of reducing the warpage of the plate-shaped molded article and improving the heat resistance, toughness, low water absorption and heat aging resistance, the flattening ratio is preferably 1.5 or more, more preferably 1.5 or more and 10.0 or less, further preferably 2.5 or more and 10.0 or less, particularly preferably more than 3.0 and 6.0 or less, and most preferably 3.1 or more and 6.0 or less. When the flat percentage is within the above range, the crushing can be more effectively prevented during the mixing, kneading, molding, or other treatment with other components, and the desired effect can be more sufficiently obtained for the molded article.

The thickness of the glass fiber or carbon fiber having a flattening of 1.5 or more is not limited to the following, but it is preferable that the short diameter d1 of the fiber cross section is 0.5 to 25 μm and the long diameter d2 of the fiber cross section is 1.25 to 250 μm. More preferably, the short diameter d1 of the fiber cross section is 3.0 to 25 μm and the long diameter d2 of the fiber cross section is 1.25 to 250 μm. When the short diameter (d1) and the long diameter (d2) are in the above ranges, the difficulty in spinning the fibers can be more effectively avoided, and the strength of the molded article can be further improved without reducing the contact area with the resin (polyamide).

Glass fibers and carbon fibers having a flattening of 1.5 or more can be produced by the methods described in patent documents 4 to 6, for example. In particular, it is preferable to use a glass fiber having a flat rate of 1.5 or more, which is produced by using either a hole plate having a plurality of holes in a bottom surface and provided with a flange extending downward from the bottom surface so as to surround the outlets of the plurality of holes, or a nozzle head for glass fiber spinning having a profiled cross section and provided with a plurality of flanges extending downward from the tip of the outer peripheral portion of the nozzle head having one or more holes. These fibrous reinforcing materials may be used as fiber bundles as roving, or may be used as chopped glass fibers after further cutting.

The "number average fiber diameter (d)" and the "weight average fiber length (l)" in the present specification can be determined by the following methods. First, the polyamide composition is put into an electric furnace, and the organic matter contained therein is incinerated. The number average fiber diameter can be determined by selecting 100 or more glass fibers (or carbon fibers) from the residue component after the treatment, observing the selected glass fibers (or carbon fibers) with a Scanning Electron Microscope (SEM), and measuring the fiber diameter (major axis) of the glass fibers (or carbon fibers). The weight-average fiber length can be determined by measuring the fiber length using an SEM photograph of the above 100 or more glass fibers (or carbon fibers) taken at a magnification of 1000.

The glass fibers or carbon fibers may be subjected to surface treatment with a silane coupling agent or the like.

The silane coupling agent is not limited to the following, and examples thereof include: aminosilanes, mercaptosilanes, epoxysilanes, vinylsilanes, and the like.

Examples of the aminosilanes include gamma-aminopropyltriethoxysilane, gamma-aminopropyltrimethoxysilane, and N- β - (aminoethyl) -gamma-aminopropylmethyldimethoxysilane.

Examples of mercaptosilanes include: gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, and the like.

These silane coupling agents may be used alone or in combination of two or more.

Among these, aminosilanes are preferable as the silane coupling agent.

In addition, the glass fiber or the carbon fiber may further contain a sizing agent.

Examples of the sizing agent include: copolymers containing, as constituent units, an unsaturated vinyl monomer containing a carboxylic anhydride and an unsaturated vinyl monomer other than the unsaturated vinyl monomer containing a carboxylic anhydride, epoxy compounds, polyurethane resins, acrylic acid homopolymers, copolymers of acrylic acid with other copolymerizable monomers, and salts thereof with primary, secondary, and tertiary amines, and the like. These sizing agents may be used alone or in combination of two or more.

Among them, from the viewpoint of the mechanical strength of the obtained polyamide composition, the sizing agent is preferably at least one selected from the group consisting of a copolymer containing, as constituent units, an unsaturated vinyl monomer containing a carboxylic anhydride and an unsaturated vinyl monomer other than the unsaturated vinyl monomer containing a carboxylic anhydride, an epoxy compound, and a polyurethane resin. Further, more preferably at least one selected from the group consisting of a copolymer containing, as constituent units, an unsaturated vinyl monomer containing a carboxylic anhydride and an unsaturated vinyl monomer other than the unsaturated vinyl monomer containing a carboxylic anhydride, and a polyurethane resin.

Glass fibers or carbon fibers can be obtained by: in a known process for producing such fibers, a fiber bundle produced by applying the sizing agent to the fibers by a known method such as a roll coater is dried, and thereby the reaction is continuously performed.

The fiber bundle may be used as roving or may be further subjected to a cutting step and then used as chopped glass.

The sizing agent is preferably applied (added) in an amount of about 0.2 mass% or more and about 3 mass% or less, and more preferably about 0.3 mass% or more and about 2 mass% or less, in terms of a solid content ratio, relative to the total mass of the glass fibers or carbon fibers.

When the amount of the sizing agent added is not less than the lower limit value in terms of solid content ratio with respect to the total mass of the glass fibers or the carbon fibers, the sizing of the fibers can be more effectively maintained. On the other hand, when the amount of the sizing agent added is not more than the above upper limit in terms of solid content ratio with respect to the total mass of the glass fibers or the carbon fibers, the thermal stability of the obtained polyamide composition can be further improved.

The fiber bundle may be dried after the cutting step, or the fiber bundle may be dried and then cut.

As the inorganic filler other than the glass fiber and the carbon fiber, wollastonite, kaolin, mica, talc, calcium carbonate, magnesium carbonate, potassium titanate fiber, aluminum borate fiber, or clay is preferable from the viewpoint of improving the strength, rigidity, and surface appearance of the molded article. More preferably wollastonite, kaolin, mica, talc, calcium carbonate or clay. Further preferred is wollastonite, kaolin, mica or talc. Wollastonite, mica or talc are particularly preferred. These inorganic fillers may be used alone or in combination of two or more.

From the viewpoint of improving toughness and surface appearance of a molded article, the average particle diameter of the inorganic filler other than the glass fiber and the carbon fiber is preferably 0.01 μm or more and 38 μm or less, more preferably 0.03 μm or more and 30 μm or less, still more preferably 0.05 μm or more and 25 μm or less, yet still more preferably 0.10 μm or more and 20 μm or less, and particularly preferably 0.15 μm or more and 15 μm or less.

By setting the average particle diameter of the inorganic filler other than the glass fiber and the carbon fiber to the upper limit or less, a polyamide composition having further excellent toughness and surface appearance of a molded article can be obtained. On the other hand, by setting the average particle diameter to the lower limit or more, a polyamide composition having a better balance between the physical properties (flowability and the like) and the cost and the handling of the powder can be obtained.

The acicular inorganic filler such as wollastonite other than glass fibers and carbon fibers has a number average particle diameter (hereinafter, may be simply referred to as "average particle diameter") as an average particle diameter. When the cross section is not circular, the maximum value of the length thereof is defined as the (number average) particle diameter.

The number average particle length (hereinafter, may be simply referred to as "average particle length") of the acicular inorganic filler is preferably a numerical range calculated from the preferable range of the number average particle diameter and the preferable range of the number average particle length (l) to the aspect ratio (l/d) of the number average particle diameter (d).

The aspect ratio (l/d) of the number average particle length (l) to the number average particle diameter (d) of the inorganic filler having a needle-like shape is preferably 1.5 or more and 10 or less, more preferably 2.0 or more and 5 or less, and further preferably 2.5 or more and 4 or less, from the viewpoint of improving the surface appearance of a molded article and preventing abrasion of metal parts such as an injection molding machine.

In addition, the inorganic filler other than the glass fiber and the carbon fiber may be subjected to surface treatment using a silane coupling agent, a titanate coupling agent, or the like.

Examples of the silane coupling agent include those similar to the silane coupling agents exemplified for the glass fibers and carbon fibers.

Among these, aminosilanes are preferable as the silane coupling agent.

Such a surface treatment agent may be used to treat the surface of the inorganic filler in advance, or may be added when the polyamide is mixed with the inorganic filler. The amount of the surface treatment agent added is preferably 0.05 mass% or more and 1.5 mass% or less with respect to the total mass of the inorganic filler.

The content of the (C) inorganic filler is preferably 5 parts by mass or more and 250 parts by mass or less, more preferably 30 parts by mass or more and 250 parts by mass or less, further preferably 50 parts by mass or more and 240 parts by mass or less, particularly preferably 50 parts by mass or more and 200 parts by mass or less, and most preferably 50 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the total of the (a) aliphatic polyamide and the (B) semi-aromatic polyamide.

By setting the content of the inorganic filler (C) to the lower limit value or more with respect to 100 parts by mass of the total of the aliphatic polyamide (a) and the semi-aromatic polyamide (B), the strength and rigidity of the obtained polyamide composition can be further improved. On the other hand, by setting the content of the inorganic filler (C) to the upper limit value or less with respect to 100 parts by mass of the total of the aliphatic polyamide (a) and the semi-aromatic polyamide (B), a polyamide composition having more excellent extrudability and moldability can be obtained.

[ (D) nucleating agent ]

(D) The nucleating agent is a substance that can produce at least one of the following effects (1) to (3) by addition.

(1) The effect of increasing the crystallization peak temperature of the polyamide composition.

(2) The effect of reducing the difference between the extrapolated onset temperature and the extrapolated termination temperature of the crystallization peak.

(3) The effect of refining the spherical grains or making the size of the molded article uniform.

The nucleating agent (D) is not limited to the following, and examples thereof include: talc, boron nitride, mica, kaolin, silicon nitride, carbon black, potassium titanate, molybdenum disulfide, and the like.

(D) The nucleating agent may be used alone or in combination of two or more.

Among them, talc or boron nitride is preferable as the (D) nucleating agent from the viewpoint of the effect of the nucleating agent.

In addition, the number average particle diameter of the (D) nucleating agent is preferably 0.01 μm or more and 10 μm or less in order to obtain a high nucleating agent effect.

The number average particle diameter of the nucleating agent can be determined by the following method. First, the molded article is dissolved in a solvent such as formic acid, which can dissolve the polyamide. Then, 100 or more nucleating agents are arbitrarily selected from the insoluble components obtained. Next, the number average particle diameter of the nucleating agent is determined by observing with an optical microscope, a scanning electron microscope, or the like, and measuring the particle diameter.

The content of the nucleating agent in the polyamide composition of the present embodiment is preferably 0.001 part by mass or more and 1 part by mass or less, more preferably 0.001 part by mass or more and 0.5 part by mass or less, and further preferably 0.001 part by mass or more and 0.09 part by mass or less, with respect to 100 parts by mass of the polyamide ((a) aliphatic polyamide and (B) semi-aromatic polyamide).

By setting the content of the nucleating agent to 100 parts by mass of the polyamide to the lower limit or more, the heat resistance of the polyamide composition tends to be further improved, and by setting the content of the nucleating agent to 100 parts by mass of the polyamide to the upper limit or less, a polyamide composition having more excellent toughness can be obtained.

(E) Lubricant agent

The lubricant (E) is not particularly limited, and examples thereof include: higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, and the like. In addition, the (E) lubricant may also be used as a molding improver.

(higher fatty acid)

Examples of the higher fatty acid include: a linear or branched, saturated or unsaturated aliphatic monocarboxylic acid having 8 to 40 carbon atoms, and the like.

Examples of the straight-chain saturated aliphatic monocarboxylic acid having 8 or more and 40 or less carbon atoms include: lauric acid, palmitic acid, stearic acid, behenic acid, montanic acid, and the like.

Examples of the branched saturated aliphatic monocarboxylic acid having 8 or more and 40 or less carbon atoms include: isopalmitic acid, isostearic acid, and the like.

Examples of the linear unsaturated aliphatic monocarboxylic acid having 8 or more and 40 or less carbon atoms include: oleic acid, erucic acid, and the like.

Examples of the branched unsaturated aliphatic monocarboxylic acid having 8 or more and 40 or less carbon atoms include: vaccenic acid, and the like.

Among these, stearic acid or montanic acid is preferable as the higher fatty acid.

(higher fatty acid metal salt)

The higher fatty acid metal salt means a metal salt of a higher fatty acid.

Examples of the metal element of the metal salt include: group 1 elements, group 2 elements and group 3 elements of the periodic table, zinc, aluminum, and the like.

As the group 1 element of the periodic table of the elements, for example, there can be mentioned: sodium, potassium, and the like.

As the group 2 element of the periodic table, for example, there can be mentioned: calcium, magnesium, and the like.

As the group 3 element of the periodic table, for example, there can be mentioned: scandium, yttrium, and the like.

Among them, the group 1 element and the group 2 element of the periodic table or aluminum are preferable, and sodium, potassium, calcium, magnesium or aluminum is more preferable.

Specific examples of the higher fatty acid metal salt include: calcium stearate, aluminum stearate, zinc stearate, magnesium stearate, calcium montanate, sodium montanate, calcium palmitate and the like.

Among them, the metal salt of higher fatty acid is preferably a metal salt of montanic acid or a metal salt of stearic acid.

(higher fatty acid ester)

The higher fatty acid ester is an ester of a higher fatty acid with an alcohol.

The higher fatty acid ester is preferably an ester of an aliphatic carboxylic acid having 8 to 40 carbon atoms and an aliphatic alcohol having 8 to 40 carbon atoms.

Examples of the aliphatic alcohol having 8 to 40 carbon atoms include: stearyl alcohol, behenyl alcohol, lauryl alcohol, and the like.

Specific examples of the higher fatty acid ester include: stearyl stearate, behenyl behenate, and the like.

(higher fatty acid amide)

The higher fatty acid amide is an amide compound of a higher fatty acid.

Examples of the higher fatty acid amide include: stearamides, oleamides, erucamides, ethylene bis stearamide, ethylene bis oleamide, N-stearyl stearamide, N-stearyl erucamide, and the like.

These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides may be used singly or in combination.

[ (F) Heat stabilizer ]

The heat stabilizer (F) is not limited to the following, and examples thereof include: phenol type heat stabilizers, phosphorus type heat stabilizers, amine type heat stabilizers, metal salts of elements of groups 3,4 and 11 to 14 of the periodic table, halides of alkali metals and alkaline earth metals, and the like.

(phenol type Heat stabilizer)

The phenol-based heat stabilizer is not limited to the following, and examples thereof include hindered phenol compounds. The hindered phenol compound has a property of imparting excellent heat resistance and light resistance to resins and fibers such as polyamide.

The hindered phenol compound is not limited to the following, and examples thereof include: n, N '-hexane-1, 6-diylbis [3- (3, 5-di-tert-butyl-4-hydroxyphenylpropionamide) ], pentaerythrityl tetrakis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], N' -hexamethylenebis (3, 5-di-tert-butyl-4-hydroxyhydrocinnamamide), triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate ], 3, 9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy ] -1, 1-dimethylethyl } -2,4,8, 10-tetraoxaspiro [5.5] undecane, a salt thereof, a hydrate thereof, and a pharmaceutically acceptable salt thereof, Diethyl 3, 5-di-tert-butyl-4-hydroxybenzylphosphonate, 1,3, 5-trimethyl-2, 4, 6-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) benzene and 1,3, 5-tris (4-tert-butyl-3-hydroxy-2, 6-dimethylbenzyl) isocyanuric acid, and the like.

These hindered phenol compounds may be used alone or in combination of two or more.

In particular, from the viewpoint of improving the heat aging resistance, N' -hexane-1, 6-diylbis [3- (3, 5-di-t-butyl-4-hydroxyphenylpropionamide) ] ] is preferable as the hindered phenol compound.

When a phenolic heat stabilizer is used, the content of the phenolic heat stabilizer in the polyamide composition is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less, based on the total mass of the polyamide composition.

When the content of the phenolic heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the gas production can be further reduced.

(phosphorus-containing Heat stabilizer)

The phosphorus-containing heat stabilizer is not limited to the following, and examples thereof include: pentaerythritol-type phosphite compounds, trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyl diphenyl phosphite, triisodecyl phosphite, phenyl diisodecyl phosphite, phenyl ditridecyl phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl tridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-t-butylphenyl) phosphite, tris (2, 4-di-t-butyl-5-methylphenyl) phosphite, tris (butoxyethyl) phosphite, 4' -butylidene-bis (3-methyl-6-t-butylphenyl) phosphite-tetrakis (tridecyl) phosphite, tri (tert-butylphenyl) phosphite, tri (nonylphenyl) phosphite, and mixtures thereof, 4, 4' -isopropylidene diphenyl diphosphite-tetrakis (C)₁₂～C₁₅Mixed alkyl) phosphite, 4 ' -isopropylidenebis (2-tert-butylphenyl) phosphite-di (nonylphenyl) phosphite, tris (biphenyl) phosphite, 1, 3-tris (2-methyl-5-tert-butyl-4-hydroxyphenyl) butane diphosphite tetra (tridecyl) phosphite, 4 ' -butylidenebis (3-methyl-6-tert-butylphenyl) phosphite-tetra (tridecyl) phosphite, 4 ' -isopropylidenebis-phenyl-tetra (C)₁～C₁₅Mixed alkyl) esters, tris (mono-and di-mixed nonylphenyl) phosphite, 4 ' -isopropylidenebis (2-tert-butylphenyl) phosphite-bis (nonylphenyl) phosphite, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris (3, 5-di-tert-butyl-4-hydroxyphenyl) phosphite, hydrogenated 4,4 ' -isopropylidenediphenyl polyphosphite, bis (4,4 ' -butylidenebis (3-methyl-6-tert-butylphenyl)) -1, 6-hexanol diphosphite di (octylphenyl) ester, 1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane diphosphite hexa (tridecyl) phosphite, Tris (4,4 '-isopropylidenebis (2-tert-butylphenyl)) phosphite, tris (1, 3-stearoyloxyisopropyl) phosphite, 2-methylenebis (4, 6-di-tert-butylphenyl) phosphite octyl ester, 2-methylenebis (3-methyl-4, 6-di-tert-butylphenyl) phosphite 2-ethylhexyl ester, 4' -biphenylenediphosphite tetrakis (2, 4-di-tert-butyl-5-methylphenyl) ester and 4Tetrakis (2, 4-di-tert-butylphenyl) 4' -biphenylene diphosphite, and the like.

These phosphorus-containing heat stabilizers may be used alone or in combination of two or more.

Among these, as the phosphorus-containing heat stabilizer, from the viewpoint of further improving the heat aging resistance and reducing the gas production amount of the polyamide composition, one or more selected from the group consisting of pentaerythritol-type phosphite compounds and tris (2, 4-di-t-butylphenyl) phosphite are preferable.

The pentaerythritol-type phosphite compound is not limited to the following, and examples thereof include: 2, 6-di-tert-butyl-4-methylphenyl-phenyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl methyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-2-ethylhexyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl isodecyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl lauryl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl isotridecyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl stearyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl ester, and mixtures thereof, 2, 6-di-tert-butyl-4-methylphenyl-cyclohexyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-benzyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl ethylcellosolve pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-butylcarbitol pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-octylphenyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl nonylphenyl pentaerythritol diphosphite, bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl ester, and mixtures thereof, Bis (2, 6-di-tert-butyl-4-ethylphenyl) pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-2, 6-di-tert-butylphenyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-2, 4-di-tert-octylphenyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl-2-cyclohexylphenyl pentaerythritol diphosphite, 2, 6-di-tert-pentyl-4-methylphenyl-phenyl pentaerythritol diphosphite, 2, 6-di-tert-butyl-4-methylphenyl ester, 2, 6-di-tert-butylphenyl ester, 2, 6-tert-, Pentaerythritol diphosphite bis (2, 6-di-t-amyl-4-methylphenyl) ester and pentaerythritol diphosphite bis (2, 6-di-t-octyl-4-methylphenyl) ester, and the like.

These pentaerythritol-type phosphite compounds may be used alone or in combination of two or more.

Among these, as the pentaerythritol-type phosphite compound, from the viewpoint of reducing the gas production amount of the polyamide composition, one or more selected from the group consisting of pentaerythritol diphosphite bis (2, 6-di-t-butyl-4-methylphenyl) ester, pentaerythritol diphosphite bis (2, 6-di-t-butyl-4-ethylphenyl) ester, pentaerythritol diphosphite bis (2, 6-di-t-pentyl-4-methylphenyl) ester and pentaerythritol diphosphite bis (2, 6-di-t-octyl-4-methylphenyl) ester are preferable, and pentaerythritol diphosphite bis (2, 6-di-t-butyl-4-methylphenyl) ester is more preferable.

When a phosphorus-containing heat stabilizer is used, the content of the phosphorus-containing heat stabilizer in the polyamide composition is preferably 0.01 mass% or more and 1 mass% or less, and more preferably 0.1 mass% or more and 1 mass% or less, based on the total mass of the polyamide composition.

When the content of the phosphorus-containing heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the gas production can be further reduced.

(thermal stabilizer of amine)

Examples of the heat stabilizer of the amine type include, but are not limited to, condensates of 4-acetoxy-2, 2,6, 6-tetramethylpiperidine, 4-stearoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-acryloyloxy-2, 2,6, 6-tetramethylpiperidine, 4- (phenylacetyloxy) -2,2,6, 6-tetramethylpiperidine, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-methoxy-2, 2,6, 6-tetramethylpiperidine, 4-stearyloxy-2, 2,6, 6-tetramethylpiperidine, 4-cyclohexyloxy-2, 2,6, 6-tetramethylpiperidine, 4-benzyloxy-2, 2,6, 6-tetramethylpiperidine, 4-phenoxy-2, 2,6, 6-tetramethylpiperidine, 4- (ethylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, 4- (phenylaminopolyloxy) -2,6, 6-tetramethylpiperidine, 4- (tetramethylcarbamoyloxy) -2,2, 2, 6-tetramethylpiperidine, 4- (4-tetramethylaminopolyloxy) -2, 6-propane-bis (di-tetramethylpropane-2, 6-tetramethylpropane-bis (4-tetramethyl-2, 6-tetramethyl-2, 6-propane) propane-bis (4-tetramethyl-2, 6-bis (4-tetramethyl-2, 6-piperidyl) propane-bis (4-2, 6-tetramethyl) propane-bis (4-2, 6-tetramethyl) propane-2, 6-bis (4-2, 6-tetramethyl) propane-bis (4-2, 6-bis (4-tetramethyl) propane-2, 6-bis (4-2, 6-tetramethyl) propane-2-tetramethyl) propane-bis (4-2, 6-2-tetramethyl) propane-bis (4-2, 6-2-bis (4-bis (4-2, 6-4-2, 6-tetramethyl) propane-bis (4-tetramethyl) propane-2, 6-bis (4-tetramethyl) propane-2, 6-2-tetramethyl) propane-2, 6-tetramethyl) propane-2-bis (4-2, 6-tetramethyl) propane-2-tetramethyl) propane-bis.

These amine-based heat stabilizers may be used alone or in combination of two or more.

When the amine-based heat stabilizer is used, the content of the amine-based heat stabilizer in the polyamide composition is preferably 0.01% by mass or more and 1% by mass or less, and more preferably 0.1% by mass or more and 1% by mass or less, based on the total mass of the polyamide composition.

When the content of the amine-based heat stabilizer is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the gas production can be further reduced.

(metal salts of group 3, group 4 and group 11 to group 14 elements of the periodic Table) As the metal salts of group 3, group 4 and group 11 to group 14 elements of the periodic Table, there is no limitation as long as they are metal salts belonging to these groups.

Among these, copper salts are preferable from the viewpoint of further improving the heat aging resistance of the polyamide composition. The copper salt is not limited to the following, and examples thereof include: copper halide, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, and copper complex salts formed by coordinating copper with a chelating agent.

Examples of the copper halide include: cuprous iodide, cuprous bromide, cupric bromide, cuprous chloride, and the like.

Examples of the chelating agent include: ethylenediamine, ethylenediamine tetraacetic acid, and the like.

These copper salts may be used alone or in combination of two or more.

Among these, as the copper salt, one or more selected from the group consisting of cuprous iodide, cuprous bromide, cupric bromide, cuprous chloride and cupric acetate is preferable, and one or more selected from the group consisting of cuprous iodide and cupric acetate is more preferable. When the above-mentioned preferred copper salts are used, a polyamide composition which is more excellent in heat aging resistance and can more effectively suppress metal corrosion of a screw or a barrel portion during extrusion (hereinafter, may be simply referred to as "metal corrosion").

When a copper salt is used as the heat stabilizer (F), the content of the copper salt in the polyamide composition is preferably 0.01 mass% or more and 0.60 mass% or less, and more preferably 0.02 mass% or more and 0.40 mass% or less, based on the total mass of the polyamide ((a) aliphatic polyamide and (B) semi-aromatic polyamide).

When the content of the copper salt is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the precipitation of copper and the corrosion of metal can be more effectively suppressed.

In addition, from the viewpoint of improving the heat aging resistance of the polyamide composition, 10 is used for the polyamide ((a) aliphatic polyamide and (B) semi-aromatic polyamide)⁶The copper salt preferably contains copper in a concentration of 10 to 2000 parts by mass, more preferably 30 to 1500 parts by mass,more preferably 50 parts by mass or more and 500 parts by mass or less.

(halides of alkali metals and alkaline earth metals)

The halides of alkali metals and alkaline earth metals are not limited to the following, and examples thereof include: potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium chloride, and the like.

These alkali metal and alkaline earth metal halides may be used singly or in combination of two or more.

Among these, as the halide of the alkali metal and the alkaline earth metal, one or more selected from the group consisting of potassium iodide and potassium bromide is preferable, and potassium iodide is more preferable, from the viewpoints of improving the heat aging resistance and suppressing the corrosion of the metal.

In the case of using the halide of the alkali metal and the alkaline earth metal, the content of the halide of the alkali metal and the alkaline earth metal in the polyamide composition is preferably 0.05 part by mass or more and 20 parts by mass or less, and more preferably 0.2 part by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the polyamide ((a) aliphatic polyamide and (B) semi-aromatic polyamide).

When the content of the halide of the alkali metal and the alkaline earth metal is within the above range, the heat aging resistance of the polyamide composition can be further improved, and the precipitation of copper and the metal corrosion can be more effectively suppressed.

The heat stabilizer (F) component described above may be used alone or in combination of two or more.

Among these, as the (F) heat stabilizer, a mixture of a copper salt and a halide of an alkali metal or an alkaline earth metal is preferable from the viewpoint of further improving the heat aging resistance of the polyamide composition.

The content ratio of the copper salt to the halide of the alkali metal and the alkaline earth metal is preferably 2/1 or more and 40/1 or less, more preferably 5/1 or more and 30/1 or less, in terms of a molar ratio of halogen to copper (halogen/copper).

When the molar ratio of halogen to copper (halogen/copper) is within the above range, the heat aging resistance of the polyamide composition can be further improved.

When the molar ratio of halogen to copper (halogen/copper) is not less than the lower limit, copper deposition and metal corrosion can be more effectively suppressed. On the other hand, when the molar ratio of halogen to copper (halogen/copper) is not more than the above upper limit, corrosion of the screw of the molding machine and the like can be more effectively prevented without substantially impairing the mechanical properties (toughness and the like).

[ (G) other polymers ]

The other polymer (G) is not particularly limited as long as it is a polymer other than polyamide, and examples thereof include: polyesters, liquid crystal polyesters, polyphenylene sulfide, polyphenylene oxide, polycarbonates, polyarylates, phenol resins, epoxy resins, and the like. The polyester is not limited to the following, and examples thereof include: polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, and the like.

The content of the (G) other polymer is preferably 1 part by mass or more and 200 parts by mass or less, more preferably 5 parts by mass or more and 100 parts by mass or less, and further preferably 5 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the total amount of the polyamides. When the content of the other polymer (G) is within the above range, a polyamide composition having excellent heat resistance and mold release properties can be obtained.

[ (H) at least one metal salt selected from the group consisting of metal phosphinate and metal phosphinate ]

As (H) at least one metal salt selected from the group consisting of a metal salt of phosphorous acid and a metal salt of hypophosphorous acid, for example, there can be mentioned: salts of phosphorous acid, hypophosphorous acid, pyrophosphorous acid or diphosphorous acid with elements of groups 1 and 2 of the periodic table of the elements, manganese, zinc, aluminum, ammonia, alkylamines, cycloalkylamines or diamines, and the like.

Among them, sodium hypophosphite, calcium hypophosphite, or magnesium hypophosphite is preferable as the metal phosphite and metal hypophosphite.

By containing at least one metal salt selected from the group consisting of a metal salt of phosphorous acid and a metal salt of hypophosphorous acid, a polyamide composition more excellent in extrusion processability and molding processability can be obtained.

[ (J) phosphite ester Compound ]

Examples of the phosphite compound (J) include: triphenyl phosphite, tributyl phosphite, and the like.

By adding the phosphite ester compound, a polyamide composition having more excellent extrusion processability and molding processability stability can be obtained.

Specific examples of the phosphite ester compound include: trioctyl phosphite, trilauryl phosphite, tridecyl phosphite, octyl diphenyl phosphite, triisodecyl phosphite, phenyl diisodecyl phosphite, phenyl ditridecyl phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl phosphite, diphenyl tridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tris (2, 4-di-tert-butylphenyl) phosphite, bis [2, 4-bis (1, 1-dimethylethyl) -6-methylphenyl ] ethyl phosphite, bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2, 6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2 phosphite, octyl 2-methylenebis (4, 6-di-t-butylphenyl) phosphite, 4 '-butylidenebis (3-methyl-6-t-butylphenyl-ditridecyl phosphite), 1, 3-tris (2-methyl-4-ditridecyl-phosphite-5-t-butylphenyl) butane, 4' -isopropylidenebis (phenyl-dialkyl phosphite), tris (2, 4-di-t-butylphenyl) phosphite, octyl 2, 2-methylenebis (4, 6-di-t-butylphenyl) phosphite, di (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and the like.

These phosphite compounds may be used alone or in combination of two or more.

[ (K) other additives ]

The polyamide composition obtained by the production method of the present embodiment may contain, in addition to the components (a) and (B), other additives (K) that are commonly used in polyamide compositions, within a range that does not impair the effects of the polyamide composition obtained by the production method of the present embodiment. Examples of other additives (K) include: coloring agents (including color concentrates) such as pigments and dyes, flame retardants, fibrillating agents, fluorescent whitening agents, plasticizers, antioxidants, ultraviolet absorbers, antistatic agents, flow improvers, extenders, elastomers, and the like.

When the polyamide composition obtained by the production method of the present embodiment contains (K) another additive, the content of the (K) other additive is different depending on the kind thereof, the use of the polyamide composition, and the like, and therefore, is not particularly limited as long as the effect of the polyamide composition obtained by the production method of the present embodiment is not impaired.

< method for producing polyamide composition >

The method for producing the polyamide composition of the present embodiment is not particularly limited as long as it is a production method including a step of melt-kneading raw material components including the aliphatic polyamide (a) and the semi-aromatic polyamide (B). For example, a method including a step of melt-kneading raw material components including the aliphatic polyamide (a) and the semi-aromatic polyamide (B) by an extruder and setting a set temperature of the extruder to a melting peak temperature Tm2+30 ℃ or less of the polyamide composition is preferable.

Examples of the method for melt-kneading the raw material components including polyamide include: a method of mixing the aliphatic polyamide (a) and the semi-aromatic polyamide (B) with other raw materials using a tumbler, a henschel mixer, or the like, supplying the mixture to a melt-kneading machine, and kneading the mixture; and (c) a method of blending the aliphatic polyamide (a) and the semi-aromatic polyamide (B) in a molten state with other raw materials from a side feeder in a single-screw or twin-screw extruder.

In the method of supplying the components constituting the polyamide composition to the melt-kneading machine, all the components may be supplied at once through the same supply port, or the components may be supplied from different supply ports.

The melt kneading temperature is preferably about 250 ℃ to 350 ℃ inclusive in a resin thermometer.

The melt-kneading time is preferably about 0.25 minutes to about 5 minutes.

The apparatus for melt-kneading is not particularly limited, and for example, a known melt-kneading machine such as a single-screw or twin-screw extruder, a Banbury mixer, or a mixing roll can be used.

Molded article

The molded article of the present embodiment is obtained by molding the polyamide composition.

The molded article of the present embodiment has a high surface gloss value. The molded article of the present embodiment preferably has a surface gloss value of 50 or more, more preferably 55 or more, and still more preferably 60 or more. When the surface gloss value of the molded article is not less than the lower limit, the obtained molded article can be suitably used as various parts for automobiles, electric and electronic products, industrial materials, daily products, household products, and the like.

The method for producing the molded article is not particularly limited, and a known molding method can be used.

The known molding method is not limited to the following methods, and examples thereof include: generally known plastic molding methods include press molding, injection molding, gas-assisted injection molding, welding molding, extrusion molding, blow molding, film molding, hollow molding, multilayer molding, melt spinning, and the like.

Since a molded article obtained by molding the polyamide composition obtained by the production method of the present embodiment is obtained from the polyamide composition, mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, surface appearance, and corrosion resistance are excellent. Therefore, the molded article can be suitably used as various parts for automobile parts, electric and electronic parts, home appliance parts, OA (office automation) equipment parts, portable equipment parts, industrial equipment parts, daily necessities, household goods, and the like, and can be suitably used for extrusion applications and the like. Among them, the molded article is suitably used as an automobile part, an electric and electronic part, a home appliance part, an OA equipment part, or a portable equipment part.

The automobile parts are not particularly limited, and examples thereof include: air intake system components, cooling system components, fuel system components, internal components, external components, electrical components, and the like.

The parts of the intake system of the automobile are not particularly limited, and examples thereof include: the engine comprises an intake manifold, an intercooler intake pipe, an exhaust pipe cover, an inner bushing, a bearing retainer, an engine frame, an engine top cover, a resonator, a throttle body and the like.

The automobile cooling system component is not particularly limited, and examples thereof include: chain guard, thermostat housing, exhaust pipe, radiator tank, alternator, delivery pipe, etc.

The automobile fuel system component is not particularly limited, and examples thereof include: fuel delivery pipes, tank housings, etc.

The automobile interior parts are not particularly limited, and examples thereof include: instrument panels, console boxes, glove boxes, steering wheels, interior trim, and the like.

The automobile exterior part is not particularly limited, and examples thereof include: molding, lamp shade, front grille, mudguard, side bumper, rearview mirror bracket, roof rail, etc.

The automobile electrical component is not particularly limited, and examples thereof include: connectors, harness connectors, motor components, lamp holders, sensor on-board switches, combination switches, and the like.

The electric and electronic components are not particularly limited, and examples thereof include: connectors, reflectors for light emitting devices, switches, relays, printed circuit boards, housings for electronic components, sockets, noise filters, bobbins, motor end caps, and the like.

As a reflector for a light emitting device, in addition to a Light Emitting Diode (LED), the reflector can be widely used for a semiconductor package such as a photodiode typified by an optical semiconductor such as a Laser Diode (LD), a Charge Coupled Device (CCD), and a Complementary Metal Oxide Semiconductor (CMOS).

The portable device member is not particularly limited, and examples thereof include: housings and structures for mobile phones, smart phones, personal computers, portable game machines, digital cameras, and the like.

The industrial equipment components are not particularly limited, and examples thereof include: gears, cams, insulation blocks, light bulbs, power tool components, agricultural machine implement components, engine covers, and the like.

The daily necessities and household goods are not particularly limited, and examples thereof include: buttons, food containers, office furniture, and the like.

The extrusion application is not particularly limited, and for example, it can be used for: films, sheets, filaments, tubes, rods, hollow molded articles, and the like.

The molded article of the present embodiment is particularly suitable for an exterior structural material in these various applications.

The structural material for exterior is a mechanical part or a structural part which requires surface processability (for example, embossability, high surface gloss, etc.) of a molded article and also requires high strength and rigidity. Specific examples of the external structural material include: furniture articles, articles for OA equipment field, automobile parts, articles for electric field, articles for other fields, and the like. Examples of furniture items include: table legs, chair legs, pedestals, cabins, parts of trucks, etc. Examples of the OA equipment field products include: notebook computer housings, and the like. Examples of the automobile parts include: a rearview mirror bracket, a rim, a spoke, a wheel cover, a wiper, a motor fan, a seat lock component, a gear, a lamp housing, a seat post, a steering wheel, a bracket, a compartment, and the like. Examples of the electric field appliances include: pulleys, gears, air heater housings, etc. Examples of the articles in other fields include: bulb housings, nails, screws, bolts and nuts, and the like.

The molded article of the present embodiment has excellent surface appearance, and therefore is also suitable for use as a molded article having a coating film formed on the surface of the molded article. The method of forming the coating film is not particularly limited as long as it is a known method, and it can be performed by coating such as spray coating or electrostatic spray coating. The coating material used for coating is not particularly limited as long as it is a known coating material, and a melamine crosslinking type polyester polyol resin coating material, an acrylic urethane coating material, or the like can be used.

Among them, the molded article of the present embodiment is excellent in mechanical strength, toughness, heat resistance, and vibration fatigue resistance, and thus is suitable as a material for automobile parts, and is excellent in sliding properties, and thus is particularly suitable as a material for parts for gears and bearings. Further, since they are excellent in mechanical strength, toughness and heat resistance, they are suitable as materials for electric and electronic parts.

[ examples ]

The present invention will be described in detail below with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. In this example, 1kg/cm²Represents 0.098 MPa.

First, the aliphatic polyamide (a), the semi-aromatic polyamide (B), and the inorganic filler (C) used in examples and comparative examples are shown below.

< constituent component >

[ (A) aliphatic Polyamide ]

A-1: polyamide 66(mw (a) 35000, mw (a)/mn (a) 2.0)

A-2: polyamide 66(Mw (30000, Mw (A))/Mn (A)) (2.0, end-capped amount: 20. mu. equivalents/g)

[ (B) semi-aromatic Polyamide ]

B-1: polyamide 6I (Mw (B) ═ 20000, Mw (B)/Mn (B): 2.0, end-capped amount: 150. mu. equivalents/g, total of amino end amount and carboxyl end amount: 110. mu. equivalents/g)

B-2: polyamide 6I (Mw (B) ═ 20000, Mw (B)/Mn (B) ═ 2.0, total amount of amino end and carboxyl end: 253 microequivalents/g)

B-3: polyamide 6I T-40 (Mw (B) (44000, Mw (B)), (B)/Mn (B) (2.8, total amount of amino terminal and carboxyl terminal: 147 microequivalents/g, manufactured by Langerhans Co., Ltd.)

[ (C) inorganic Filler Material ]

C-1: glass Fiber (GF) (manufactured by Nippon electric glass under the trade name "ECS 03T 275H", number average fiber diameter (average particle diameter): 10 μm (perfect circle) and cut length: 3mm)

In the present example, the number average fiber diameter of the glass fiber was measured as follows.

First, the polyamide composition is put into an electric furnace, and organic matter contained in the polyamide composition is incinerated. The number average fiber diameter was determined by observing 100 or more glass fibers arbitrarily selected from the residue part after the treatment with a Scanning Electron Microscope (SEM) and measuring the fiber diameters of the glass fibers.

< raw Material of Polyamide >

The aliphatic polyamide (a) and the semi-aromatic polyamide (B) used in the examples and comparative examples were produced by appropriately using the following (a) and (B).

[ (a) dicarboxylic acid) ]

(a-1) adipic acid (ADA) (manufactured by Wako pure chemical industries, Ltd.)

(a-2) Isophthalic acid (IPA) (manufactured by Wako pure chemical industries, Ltd.)

[ (b) diamine)

(b-1)1, 6-diaminohexane (hexamethylenediamine) (C6DA) (manufactured by Tokyo chemical industries, Ltd.)

< production of Polyamide >

Next, the production methods of (A) the aliphatic polyamides A-1 and A-2 and (B) the semi-aromatic polyamides B-1 and B-2 will be described.

Production example 1 production of aliphatic Polyamide A-1 (Polyamide 66)

The polymerization of the polyamide was carried out by the "hot melt polymerization method" as follows.

1500g of an equimolar salt of adipic acid and hexamethylenediamine was dissolved in 1500g of distilled water to prepare a uniform aqueous solution of 50 mass% in equimolar amount of the raw material monomer. The aqueous solution was charged into an autoclave having an internal volume of 5.4L, and replaced with nitrogen. While stirring at a temperature of 110 ℃ to 150 ℃, water vapor is slowly extracted and concentrated to a solution concentration of 70 mass%. Then, the internal temperature was raised to 220 ℃. At this time, the autoclave was pressurized to 1.8 MPa. This state was maintained for 1 hour until the internal temperature reached 245 ℃, and the reaction was carried out for 1 hour while maintaining the pressure at 1.8MPa with slowly withdrawing water vapor. Then, the pressure was reduced for 1 hour. Then, the autoclave was maintained under reduced pressure of 650 torr for 10 minutes by using a vacuum apparatus. At this time, the final internal temperature of the polymerization was 265 ℃. Then, the mixture was pressurized with nitrogen gas, pelletized from a lower spinneret (nozzle), water-cooled, cut, and discharged in the form of pellets, which were dried at 100 ℃ for 12 hours in a nitrogen atmosphere, to obtain an aliphatic polyamide a-1 (polyamide 66). Mw (a) 35000, mw (a)/mn (a) 2.0.

Production example 2 production of aliphatic Polyamide A-2 (Polyamide 66)

A polymerization reaction ("hot melt polymerization method") of polyamide was carried out in the same manner as described in production example 1, except that 1500g of an equimolar salt of adipic acid and hexamethylenediamine and 0.5 mol% of acetic acid with respect to the total equimolar salt component were dissolved in 1500g of distilled water to prepare a uniform aqueous solution of 50 mass% equimolar of the raw material monomer, thereby obtaining pellets of aliphatic polyamide a-2 (polyamide 66). Mw (a) 30000, mw (a)/mn (a) 2.0, end-capped end amount: 20 microequivalents per gram.

Production example 3 semi-aromatic Polyamide B-1 (Polyamide 6I)

1500g of an equimolar salt of isophthalic acid and hexamethylenediamine and 4.0 mol% of acetic acid with respect to the total equimolar salt component were dissolved in 1500g of distilled water to prepare a uniform aqueous solution of 50 mass% in equimolar amount of the raw material monomer. While stirring at a temperature of 110 ℃ to 150 ℃, water vapor is slowly extracted and concentrated to a solution concentration of 70 mass%. Then, the internal temperature was raised to 220 ℃. At this time, the autoclave was pressurized to 1.8 MPa. This state was maintained for 1 hour until the internal temperature reached 245 ℃, and the reaction was carried out for 1 hour while maintaining the pressure at 1.8MPa with slowly withdrawing water vapor. Then, the pressure was reduced for 30 minutes. Then, the autoclave was maintained under reduced pressure of 650 torr for 10 minutes by using a vacuum apparatus. At this time, the final internal temperature of the polymerization was 265 ℃. Then, the mixture was pressurized with nitrogen gas, formed into strands from a lower spinneret (nozzle), water-cooled, cut, discharged in the form of pellets, and dried at 100 ℃ for 12 hours in a nitrogen atmosphere, thereby obtaining a semi-aromatic polyamide B-1 (polyamide 6I). Mw (b) 20000, mw (b)/mn (b) 2.0, end-capped end amount: 150 microequivalents/g, total of amino terminal amount and carboxyl terminal amount: 110 microequivalents per gram.

Production example 4 semi-aromatic Polyamide B-2 (Polyamide 6I)

A polymerization reaction ("hot melt polymerization method") of a polyamide was carried out by the method described in production example 3 to obtain a pellet of a semi-aromatic polyamide B-2 (polyamide 6I) except that 1500g of an equimolar salt of isophthalic acid and hexamethylenediamine and an excess of 1.5 mol% of adipic acid with respect to the total equimolar salt component were dissolved in 1500g of distilled water to prepare a uniform aqueous solution of an equimolar 50 mass% of the raw material monomer. Mw (b) ═ 20000, mw (b)/mn (b) ═ 2.0, total of amino end amount and carboxyl end amount: 253 micro equivalent/g.

< production of Polyamide composition >

Examples 1 to 3 and comparative examples 1 and 2

A polyamide composition was produced as follows using the aliphatic polyamide (a) and the semi-aromatic polyamide (B) in the types and proportions shown in table 1 below.

The polyamides obtained in the above production examples were dried in a nitrogen gas flow to adjust the water content to about 0.2 mass%, and then used as a raw material of a polyamide composition.

As a production apparatus for the polyamide composition, a twin-screw extruder [ ZSK-26 MC: manufactured by kekuron corporation (germany) ].

The twin-screw extruder has an upstream side supply port in the first barrel from the upstream side of the extruder, a downstream side first supply port in the sixth barrel, and a downstream side second supply port in the ninth barrel. Further, the twin-screw extruder had an L/D of 48 and the number of barrels of 12.

In the twin-screw extruder, the temperature from the upstream side supply port to the die was set to the melting point Tm2+20 ℃ of each polyamide (A) produced in the above production examples, the screw rotation speed was set to 250rpm, and the discharge amount was set to 25 kg/hr.

The aliphatic polyamide (a) and the semi-aromatic polyamide (B) were dry-blended so as to have the types and proportions shown in table 1 below, and then supplied from an upstream supply port of a twin-screw extruder, and the melt-kneaded product extruded from the die was cooled in a strand shape and granulated, thereby obtaining pellets of a polyamide composition (containing no GF).

Next, a case of producing a polyamide composition containing 60 mass% GF (polyamide: GF 100 parts by mass: 150 parts by mass) shown in table 1 will be described. The aliphatic polyamide (a) and the semi-aromatic polyamide (B) were dry-blended, and then supplied from an upstream supply port of a twin-screw extruder, and the glass fiber (C) as an inorganic filler was supplied from a downstream first supply port of the twin-screw extruder, and the melt-kneaded product extruded from the die was cooled in a strand shape and granulated, thereby obtaining pellets (containing GF) of the polyamide composition.

The obtained pellets of the polyamide composition were dried in a nitrogen gas stream to adjust the water content in the polyamide composition to 500ppm or less.

< method for measuring physical Properties of Polyamide composition >

The following physical properties were evaluated using the polyamide composition having the water content adjusted. The evaluation results are shown in table 1 below.

[ Property 1] melting Peak temperature Tm2 (melting Point), crystallization Peak temperature Tc, and crystallization enthalpy

The measurement was carried out according to JIS-K7121 by using Diamond-DSC manufactured by Perkin Elmer. Specifically, the measurement was performed as follows.

First, about 10mg of a sample was heated from room temperature to 300 ℃ or more and 350 ℃ or less at a heating rate of 20 ℃/min depending on the melting point of the sample under a nitrogen atmosphere. The highest peak temperature of the endothermic peak (melting peak) occurring at this time was taken as Tm1 (. degree. C.). Subsequently, the temperature was maintained at the highest temperature of the temperature rise for 2 minutes. At this maximum temperature, the polyamide is in a molten state. Then, the temperature is reduced to 30 ℃ at a temperature reduction speed of 20 ℃/min. The exothermic peak appearing at this time was defined as a crystallization peak, the crystallization peak temperature as Tc, and the crystallization peak area as the enthalpy of crystallization Δ H (J/g). Then, the sample was held at 30 ℃ for 2 minutes, and then heated from 30 ℃ to 280 ℃ or more and 300 ℃ or less at a heating rate of 20 ℃/minute depending on the melting point of the sample. The highest peak temperature of the endothermic peak (melting peak) occurring at this time was taken as melting point Tm2 (. degree.C.).

[ Property 2] tan delta Peak temperature

The temperature dispersion spectrum of the dynamic viscoelasticity of a test piece obtained by cutting a parallel portion of an ASTM D1822 TYPE L test piece into a strip was measured under the following conditions using a viscoelasticity measurement and analysis apparatus (manufactured by Rheology: DVE-V4). The test piece size was 3.1mm (width) × 2.9mm (thickness) × 15mm (length: inter-jig distance).

(measurement conditions)

Measurement mode: stretching

Waveform: sine wave

Frequency: 3.5Hz

Temperature range: 0 ℃ or higher and 180 ℃ or lower

Temperature rise rate: 2 ℃ per minute

Static load: 400g

Displacement amplitude: 0.75 μm

The ratio of the loss modulus of elasticity E2 to the storage modulus of elasticity E1 (E2/E1) was defined as tan. delta. and the highest temperature was defined as the tan. delta. peak temperature.

[ Property 3] Mw (weight average molecular weight), Mn (number average molecular weight), molecular weight distribution Mw/Mn, Mw (A) -Mw (B)

Mw (weight average molecular weight) and Mn (number average molecular weight) were measured by GPC (HLC-8020, manufactured by Tosoh corporation, hexafluoroisopropanol solvent, PMMA (polymethyl methacrylate) standards (manufactured by Polymer Laboratories, Inc.)). From the values, Mw (A) -Mn (B) and molecular weight distribution Mw/Mn were calculated.

The content (% by mass) of the polyamide having a number average molecular weight Mn of 500 or more and 2000 or less is calculated from the elution curve (vertical axis: signal intensity by a detector, horizontal axis: elution time) of each sample obtained by GPC, from the area of the region surrounded by the baseline and the elution curve and having a number average molecular weight of 500 or more and less than 2000 and the area of the region surrounded by the baseline and the elution curve.

[ Property 4][NH₂]/([NH₂]+[COOH])

The amount of amino terminal ([ NH ] was measured by the following (4-1) and (4-2)₂]) And the amount of carboxyl terminal ([ COOH ]]) Calculate [ NH ]₂]/([NH₂]+[COOH])。

(4-1) amount of amino terminal ([ NH ]₂])

The amount of the amino terminal bonded to the polymer terminal of the polyamide composition was determined by neutralization titration as follows.

3.0g of the polyamide composition was dissolved in 100mL of a 90 mass% aqueous phenol solution, and the resulting solution was titrated with 0.025N hydrochloric acid to determine the amount of the amino terminal (microequivalents/g). The endpoint was determined from the indicated value of the pH meter.

(4-2) carboxyl terminal amount ([ COOH ])

The amount of the carboxyl terminal bonded to the polymer terminal of the polyamide composition was measured by neutralization titration as follows.

4.0g of the polyamide composition was dissolved in 50mL of benzyl alcohol, and the resulting solution was titrated with 0.1N NaOH to determine the amount of carboxyl terminals (microequivalents/g). The end point was determined by the colour change of the phenolphthalein indicator.

[ Property 5] amount of Ends capped

By passing¹The content of the terminal-capped terminal of the polyamide contained in the polyamide composition, the aliphatic polyamide and the semi-aromatic polyamide was quantified by H-NMR measurement as follows.

15mg of the polyamide composition, the aliphatic polyamide and the semi-aromatic polyamide were dissolved in a mixed solvent of 0.7g of deuterated sulfuric acid and 0.7g of deuterated trifluoroacetic acid, and the mixture was allowed to stand overnight. Then, using the obtained solution, JNM ECA-500, a nuclear magnetic resonance analyzer manufactured by Japan Electron¹Analysis by H-NMR on endAnd (4) carrying out measurement.

The amount of the terminal-blocked ends was determined by calculating the integrated ratio from the peak area of 1.98ppm of the proton due to acetic acid bonded to the terminal of the aliphatic diamine unit, based on the peak area of 3.04ppm of the proton due to the methylene group of the main chain amine.

[ Property 6][NH₂]+[COOH]

By passing¹The contents of the carboxyl terminal and the amino terminal of the polyamide contained in the polyamide composition and the semi-aromatic polyamide were quantified by H-NMR measurement as follows.

The polyamide composition and 15mg of the semi-aromatic polyamide were dissolved in a mixed solvent of 0.7g of deuterated sulfuric acid and 0.7g of deuterated trifluoroacetic acid, and the mixture was allowed to stand overnight. Then, using the obtained solution, JNM ECA-500, a nuclear magnetic resonance analyzer manufactured by Japan Electron¹Analysis by H-NMR, the end was determined.

The integrated ratio was calculated from a peak area of 2.47ppm of hydrogen of an adjacent methylene group due to adipic acid, a peak area of 8.07ppm of hydrogen on a carbon of an adjacent benzene ring due to an isophthalic acid unit, and a peak area of 7.85ppm of hydrogen on a carbon of an adjacent benzene ring due to a terephthalic acid unit, based on a peak area of 3.04ppm of a proton of a methylene group due to a main chain amine, thereby determining the carboxyl end amount. The amount of amino terminal was determined by calculating the integrated ratio from the peak area of 2.67 to 2.69ppm of hydrogen on the carbon adjacent to methylene group due to hexamethylenediamine group.

The amount of amino terminal ([ NH ]) obtained by the above measurement was used₂]) And the amount of carboxyl terminal ([ COOH ]]) Calculate [ NH ]₂]+[COOH]。

[ Property 7] tensile Strength

Using an injection molding machine [ PS-40E: type A multipurpose test piece was molded according to ISO 3167. Specific molding conditions were set to 25 seconds for injection + dwell time and 15 seconds for cooling, 80 ℃ for mold temperature, and 20 ℃ for melting peak temperature (Tm2) + for high-temperature side of polyamide for molten resin.

Using the multipurpose test piece type A molded piece thus obtained, a tensile test was conducted at a drawing speed of 50 mm/min under a temperature condition of 23 ℃ in accordance with ISO527, and the tensile yield stress was measured as the tensile strength.

The temperature condition was set to 80 ℃ and the other conditions were set in the same manner as described above, and the tensile strength at 80 ℃ was measured.

[ Property 8] Corrosion resistance

The sample particles and the weight-measured carbon steel (SS400) were placed in an SUS-made closed vessel, and nitrogen gas was substituted. Then, the closed vessel was heated and kept at an internal temperature of 300 ℃ for 10 hours, and the weight of the carbon steel after cooling was measured. The degree of corrosion was judged as a change in weight of carbon steel, and the corrosion resistance was evaluated according to the following evaluation criteria.

(evaluation criteria)

A: weight before and after the test was not reduced

B: the weight change before and after the test is more than or equal to 0.1g and less than 0.5g

C: the weight change before and after the test is not less than 0.5g and not more than 1g

D: the weight change before and after the test is 1g or more

[ Properties 9] surface gloss value

Flat molded pieces were produced as follows.

Injection molding machine [ NEX50III-5 EG: manufactured by hitachi resin industries, the cooling time was 25 seconds, the screw rotation speed was 200rpm, the mold temperature was Tan δ peak temperature +5 ℃, and the cylinder temperature was (Tm2+10) ° c or more and (Tm2+30) ° c or less, and the injection pressure and the injection speed were appropriately adjusted so that the filling time was in the range of 2.0 ± 0.1 seconds, thereby producing flat molded pieces (6cm × 9cm, thickness 2 mm).

The central part of the thus-produced flat molded sheet was measured for 60-degree gloss in accordance with JIS-K7150 using a gloss meter (IG 320 manufactured by HORIBA Co., Ltd.). The larger the measurement value, the more excellent the surface appearance was judged.

[ Property 10] MD (mold Scale) in Molding

The molding described in "property 9" was continuously performed 500 times, and the vent after the molding was completed was visually checked.

The evaluation criteria for gas generation during molding are as follows. The case where a molded article was obtained without any problem was evaluated as leading to improvement in productivity.

(evaluation criteria)

A: no deposit was observed at the exhaust port

B: the presence of deposits in the exhaust port

C: the presence of deposits on the exhaust port just started to clog

D: the presence of deposits and clogging in the exhaust port

[ Property 11] Retention ratio of flexural elastic modulus after Water absorption

ISO dumbbell test pieces having a thickness of 4mm were prepared as test pieces. Using the obtained test piece, the flexural modulus was measured according to ISO 178. Further, the ISO dumbbell test piece was placed in a constant temperature and humidity (23 ℃ C., 50 RH%) atmosphere to reach water absorption equilibrium, and then the flexural modulus was measured according to ISO 178. The retention ratio of flexural modulus after water absorption was determined by the following equation.

Retention (%) of flexural modulus after Water absorption-flexural modulus after Water absorption/flexural modulus before Water absorption X100

TABLE 1

As shown in table 1, molded articles (examples 1 to 3) obtained using a polyamide composition containing 50 to 99 parts by mass of (a) an aliphatic polyamide and 1 to 50 parts by mass of (B) a semi-aromatic polyamide and having a capped end amount of 5 to 180 microequivalents per gram expressed as an equivalent to 1 gram of at least one polyamide selected from the group consisting of (a) an aliphatic polyamide and (B) a semi-aromatic polyamide and a Tan δ peak temperature of the polyamide composition of 90 ℃ or higher are more excellent in MD, surface gloss value and corrosion resistance during molding than molded articles (comparative examples 1 and 2) obtained using a polyamide composition having a capped end amount of 0 (i.e., having no capped end).

In addition, the molded articles obtained using the polyamide composition having a terminal amount of 40. mu. equivalents/g or more (examples 1 and 2) had particularly good MD and corrosion resistance during molding, as compared with the molded article obtained using the polyamide composition having a terminal amount of less than 40. mu. equivalents/g (example 3).

Industrial applicability

The polyamide composition of the present invention is excellent in mechanical properties, particularly water absorption rigidity, thermal rigidity, fluidity, surface appearance, corrosion resistance and the like, and can be suitably used as a molding material for various parts for automobiles, electric and electronic appliances, industrial materials, daily use products, household goods and the like.

Claims

1. A polyamide composition comprising 50 to 99 parts by mass of (A) an aliphatic polyamide and 1 to 50 parts by mass of (B) a semi-aromatic polyamide,

the (A) aliphatic polyamide comprises diamine and dicarboxylic acid,

the semi-aromatic polyamide (B) contains dicarboxylic acid units containing at least 75 mol% of isophthalic acid units and diamine units containing at least 50 mol% of diamine units having 4 to 10 carbon atoms,

an amount of a terminal-blocked end represented by an equivalent of 1g to at least one polyamide selected from the group consisting of the (A) aliphatic polyamide and the (B) semi-aromatic polyamide is 5 to 180 micro equivalents/g,

the polyamide composition has a tan delta peak temperature of 90 ℃ or higher.

2. The polyamide composition according to claim 1, wherein,

the amount of the acetic acid-terminated end group represented by an equivalent to 1g of the semi-aromatic polyamide (B) is 5 to 180 [ mu ] equivalents/g.

3. The polyamide composition according to claim 1 or 2, wherein,

the polyamide composition has a weight average molecular weight Mw of 15000 to 35000.

4. Polyamide composition according to any one of claims 1 to 3, wherein,

the polyamide composition has a molecular weight distribution Mw/Mn of 2.6 or less.

5. The polyamide composition according to any one of claims 1 to 4, wherein,

the sum of the amino terminal amount and the carboxyl terminal amount, which is expressed as an equivalent to 1g of the polyamide in the polyamide composition, is 70 to 145 microequivalents per g.

6. The polyamide composition according to any one of claims 1 to 5, wherein,

a ratio of the amount of the amino terminal to the total amount of the amino terminal and the amount of the carboxyl terminal { amount of amino terminal/(amount of amino terminal + amount of carboxyl terminal) } is 0.25 or more and 0.4 or less.

7. The polyamide composition according to any one of claims 1 to 6, wherein,

the (A) aliphatic polyamide is polyamide 66 or polyamide 610.

8. The polyamide composition according to any one of claims 1 to 7, wherein,

in the (B) semi-aromatic polyamide, the content of the isophthalic acid unit is 100 mol% with respect to the total amount of the dicarboxylic acid units.

9. The polyamide composition according to any one of claims 1 to 8, wherein,

the semi-aromatic polyamide (B) is polyamide 6I.

10. The polyamide composition according to any one of claims 1 to 9, wherein,

the semi-aromatic polyamide (B) has a weight average molecular weight Mw (B) of 10000 to 25000 inclusive.

11. The polyamide composition according to any one of claims 1 to 10, wherein,

the semi-aromatic polyamide (B) has a molecular weight distribution Mw (B)/Mn (B) of 2.4 or less.

12. The polyamide composition according to any one of claims 1 to 11, wherein,

the difference { mw (a) -mw (B) } between the weight average molecular weight mw (a) of the aliphatic polyamide (a) and the weight average molecular weight mw (B) of the semi-aromatic polyamide (B) is 10000 or more.

13. The polyamide composition according to any one of claims 1 to 12, wherein,

the polyamide composition further contains at least one metal salt selected from the group consisting of a metal salt of phosphorous acid and a metal salt of hypophosphorous acid.

14. The polyamide composition according to any one of claims 1 to 13, wherein,

the polyamide composition also contains a phosphite compound.

15. The polyamide composition according to any one of claims 1 to 14, wherein,

the polyamide composition further contains 5 to 250 parts by mass of (C) an inorganic filler per 100 parts by mass of the total of the aliphatic polyamide (A) and the semi-aromatic polyamide (B).

16. A molded article obtained by molding the polyamide composition according to any one of claims 1 to 15, wherein the molded article has a surface gloss of 50 or more.

17. A semi-aromatic polyamide comprising dicarboxylic acid units containing at least 75 mol% of isophthalic acid units and diamine units containing a chain aliphatic diamine having 4 or more and 10 or less carbon atoms, wherein,

the amount of the terminal-blocked end represented by an equivalent to 1g of the semi-aromatic polyamide is 5 to 180 microequivalents/g,

the semi-aromatic polyamide has a tan delta peak temperature of 90 ℃ or higher.

18. The semi-aromatic polyamide according to claim 17,

the amount of the acetic acid-terminated end represented by an equivalent to 1g of the semi-aromatic polyamide is 5 to 180 microequivalents/g.

19. The semi-aromatic polyamide according to claim 17 or 18,

the total of the amino terminal amount and the carboxyl terminal amount, which is expressed as an equivalent to 1g of the semi-aromatic polyamide, is 50 to 155 microequivalents/g.

20. The semi-aromatic polyamide according to any one of claims 17 to 19,

the semi-aromatic polyamide has a weight average molecular weight Mw of 10000 to 35000.

21. The semi-aromatic polyamide according to any one of claims 17 to 20,

the semi-aromatic polyamide has a molecular weight distribution Mw/Mn of 2.6 or less.