JP2017203151A - Polyamide resin composition and chemical resistance improving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition having excellent chemical resistance and strength.SOLUTION: A polyamide resin composition contains polyamide resin (A) and glass fiber (B). In the polyamide resin composition, the polyamide resin (A) has at least one melting point in a range of less than 240°C and at least one melting point in a range of 240°C or more, and also has one crystallization peak temperature.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition having excellent chemical resistance and a method for improving chemical resistance.

  Polyamide resins have excellent mechanical properties (such as mechanical strength, rigidity and impact resistance), heat resistance, and chemical resistance, so they are used in clothing, industrial materials, automobiles, electrical and electronic parts, and other industrial products. It is used in various industrial fields.

  Speaking of materials used in automobile engine rooms, recently, assuming use in cold regions, long-term coolant (LLC), which is an antifreeze liquid in cooling system components, is used to suppress deterioration of resin against calcium chloride, which is an antifreezing agent. The suppression of the deterioration of the resin due to the above) is demanded more highly. For use in parts relating to automobile engine rooms, polyamide resins are also required to have calcium chloride resistance and hydrolysis resistance as described above.

  As a technique for improving the calcium chloride resistance and hydrolysis resistance of a polyamide resin, a polyamide having a long carbon chain (long-chain polyamide; a polyamide having a high ratio of methylene chains to amide bonds) has been conventionally known.

  On the other hand, since long-chain polyamide has a low melting point, a mixture with polyamide 66 or the like is disclosed in order to increase heat resistance (see, for example, Patent Documents 1 to 3).

JP-A-60-88066 JP 2008-144132 A Special table 2013-523930 gazette

  An object of the present invention is to provide a polyamide resin composition having better chemical resistance and strength suitable for parts used in an automobile engine room, and to provide a method for improving chemical resistance. Is.

  As a result of intensive studies in order to solve the above problems, the present inventors have obtained a polyamide resin composition comprising a polyamide resin and glass fiber, and the polyamide resin is a specific resin in the polyamide resin composition. It has been found that a polyamide resin composition having excellent chemical resistance can be obtained by having a melting point in the temperature range and having a single crystallization peak temperature.

  That is, the polyamide resin composition of the present invention is a polyamide resin composition comprising the polyamide resin (A) and the glass fiber (B), and in the polyamide resin composition, the polyamide resin (A) is 240 ° C. It has at least one melting point below and at least one melting point above 240 ° C. and one crystallization peak temperature.

The polyamide resin (A) has a melting point of 240 ° C. or lower, a carbon number / nitrogen number ratio (C / N ratio) of 7 or higher, and a melting point of 240 ° C. or higher and carbon It is preferable to include polyamide (a-2) having a number / nitrogen number ratio (C / N ratio) of less than 7.
The polyamide (a-1) preferably contains 50 mol% or more of units composed of aliphatic diamine and aliphatic dicarboxylic acid and / or units composed of ω-aliphatic aminocarboxylic acid.
The polyamide (a-1) is selected from the group consisting of polyamide 410, polyamide 412, polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 1010, polyamide 1012 and a copolymer polyamide containing these as constituent components. It is preferable that it is a seed or more.

The polyamide (a-2) preferably contains 50 mol% or more of units composed of aliphatic diamine and aliphatic dicarboxylic acid.
The polyamide (a-2) is preferably at least one selected from the group consisting of polyamide 46, polyamide 56, polyamide 66, and copolymerized polyamide containing these as constituent components.

The crystallization peak temperature of the polyamide resin composition is not less than the crystallization peak temperature of the polyamide (a-1) and preferably not more than the crystallization peak temperature of the polyamide (a-2).
It is preferable that 30-70 mass% of polyamide (a-1) and 30-70 mass% of polyamide (a-2) are included with respect to 100 mass% of polyamide in the polyamide resin (A).

  The method for improving the chemical resistance of the present invention is a method for improving the chemical resistance of a polyamide resin composition comprising (A) a polyamide resin and (B) glass fiber, and (A) as a polyamide resin (A) Polyamide resin having at least one melting point below 240 ° C. and at least one melting point above 240 ° C. and having a single crystallization peak temperature can improve the chemical resistance of the polyamide resin composition. It is to improve.

  According to the present invention, a polyamide resin composition excellent in chemical resistance and strength can be provided.

The present invention will be specifically described below.
The polyamide resin composition of the present invention comprises a polyamide resin (A) and glass fibers (B). Hereinafter, each component will be described in detail.

[Polyamide resin (A)]
The polyamide resin (A) used in the present invention contains a polyamide (a-1) having a melting point of 240 ° C. or less and a carbon number / nitrogen number ratio (C / N ratio) of 7 or more. preferable. By including such polyamide (a-1), it tends to be excellent in chemical resistance. The ratio of carbon number / nitrogen number (C / N ratio) of the polyamide (a-1) is preferably 7 or more, and more preferably 8 or more. The upper limit of the ratio of carbon number / nitrogen number (C / N ratio) is not particularly limited, but is preferably 15 or less, more preferably 12 or less, and even more preferably 10 or less. When the ratio of carbon number / nitrogen number is within the above range, it tends to be more excellent in chemical resistance and heat resistance. The C / N ratio of the copolymerized polyamide can be determined as an average value calculated from the molar ratio of the copolymerization ratio as the C / N ratio.

  The content of the polyamide (a-1) is preferably 30 to 70% by mass with respect to 100% by mass of the polyamide in the polyamide resin (A). More preferably, it is 35-65 mass%, More preferably, it is 40-60 mass%. When the content is within the above range, the chemical resistance tends to be more excellent.

  The melting point is a value measured by differential scanning calorimetry (DSC) according to JIS K7121. Specifically, it is the melting peak temperature when heated at a heating rate of 20 ° C./min. The melting point can be measured by DSC7 (manufactured by Perkin Elmer). Hereinafter, the meaning of the melting point and the measuring method are the same in this specification.

  The melting point of the polyamide (a-1) is preferably 240 ° C. or less, more preferably 150 to 240 ° C., further preferably 180 to 240 ° C., and particularly preferably 190 to 230 ° C. When the melting point is within the above range, it tends to be more excellent in chemical resistance, molding processability and appearance.

  The polyamide resin (A) used in the present invention contains a polyamide (a-2) having a melting point of 240 ° C. or higher and a carbon number / nitrogen number ratio (C / N ratio) of less than 7. preferable. By including such a polyamide (a-2), it tends to be excellent in mechanical strength and thermal rigidity. The ratio of carbon number / nitrogen number (C / N ratio) of the polyamide (a-2) is more preferably 4 or more and less than 7, and further preferably 5 or more and less than 7. The C / N ratio of the copolymerized polyamide can be determined as an average value calculated from the molar ratio of the copolymerization ratio as the C / N ratio, as in the polyamide (a-1).

  The content of the polyamide (a-2) is preferably 30 to 70% by mass with respect to 100% by mass of the polyamide in the polyamide resin (A). More preferably, it is 35-65 mass%, More preferably, it is 40-60 mass%. When the content is in the above range, the thermal rigidity tends to be more excellent.

  The melting point of the polyamide (a-2) is preferably 240 ° C. or higher, more preferably 240 to 320 ° C., further preferably 240 to 300 ° C., and particularly preferably 250 to 280 ° C. When the melting point is within the above range, it tends to be more excellent in mechanical strength, rigidity during heat, and moldability.

  Polyamide means a polymer compound having a —CO—NH— (amide) bond in the main chain. The polyamide (a-1) and polyamide (a-2) are not particularly limited. For example, (a) polyamide obtained by ring-opening polymerization of lactam, (b) obtained by self-condensation of ω-aminocarboxylic acid. Polyamide obtained by condensing (c) diamine and dicarboxylic acid, and copolymers thereof.

  Although it does not specifically limit as a lactam used as the raw material of said (a) polyamide, For example, a pyrrolidone, a caprolactam, an undecaractam, a dodecaractam, etc. are mentioned.

  Moreover, it does not specifically limit as (omega) omega-aminocarboxylic acid used as the raw material of the said (b) polyamide resin, For example, the omega-amino fatty acid etc. which are the ring-opening compounds by the water of the said lactam are mentioned. The above (a) polyamide and (b) polyamide may each be a condensation product of two or more kinds of lactam or ω-aminocarboxylic acid.

  The diamine (monomer) used as the raw material for the polyamide (c) is not particularly limited, and examples thereof include linear aliphatic diamines such as hexamethylene diamine and pentamethylene diamine; 2-methylpentane diamine and 2- Examples include branched aliphatic diamines such as ethylhexamethylenediamine; aromatic diamines such as p-phenylenediamine and m-phenylenediamine; and alicyclic diamines such as cyclohexanediamine, cyclopentanediamine, and cyclooctanediamine.

On the other hand, the dicarboxylic acid (monomer) used as the raw material for the polyamide (c) is not particularly limited. For example, aliphatic dicarboxylic acids such as adipic acid, pimelic acid and sebacic acid; phthalic acid and isophthalic acid Aromatic dicarboxylic acids; cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid and the like.
The (c) polyamide may be a single type or a combination of two or more types of diamines and dicarboxylic acids.

  The polyamide (a-1) preferably contains 50 mol% or more of units composed of aliphatic diamine and aliphatic dicarboxylic acid and / or units composed of ω-aliphatic aminocarboxylic acid. More preferably, it is 60 mol% or more, More preferably, it is 80 mol% or more, Especially preferably, it is 90 mol% or more, Most preferably, it is 100 mol%. When the units composed of these aliphatic compounds are within the above range, the toughness and moldability tend to be superior.

  Although it does not specifically limit as polyamide (a-1), For example, polyamide 410 (polytetramethylene sebacamide), polyamide 412 (polytetramethylene dodecamide), polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (Polyhexamethylene dodecane), polyamide 11 (polyundecanamide), polyamide 12 (polydodecanamide), polyamide 1010 (polydecane sebacamide), polyamide 1012 (polydecane dodecamide), and constituents thereof 1 or more types selected from the group consisting of copolymerized polyamides included. Among these, at least one selected from the group consisting of polyamide 410, polyamide 412, polyamide 610, polyamide 612, and a copolymer polyamide containing these as a constituent component is preferable, and includes polyamide 410, polyamide 412, polyamide 610, and polyamide 612. One or more selected from the group is more preferred. By being 1 or more types selected from these groups, it exists in the tendency which is excellent with chemical-resistance, moldability, and external appearance.

  The polyamide (a-2) preferably contains 50 mol% or more of units composed of aliphatic diamine and aliphatic dicarboxylic acid. More preferably, it is 60 mol% or more, More preferably, it is 80 mol% or more, Especially preferably, it is 90 mol% or more, Most preferably, it is 100 mol%. When the units composed of these aliphatic compounds are within the above range, the toughness and moldability tend to be superior.

  The polyamide (a-2) is not particularly limited. For example, polyamide 4 (polyα-pyrrolidone), polyamide 6 (polycaproamide), polyamide 46 (polytetramethylene adipamide), polyamide 56 (polypentamethylene) Adipamide), polyamide 66 (polyhexamethylene adipamide), and one or more selected from the group consisting of copolymerized polyamides containing these as constituents. Among these, at least one selected from the group consisting of polyamide 46, polyamide 56, polyamide 66, and a copolymerized polyamide containing these as constituent components is preferable, and 1 selected from the group consisting of polyamide 46, polyamide 56, and polyamide 66 is preferable. More than species are more preferred. By being 1 or more types selected from these groups, it exists in the tendency which is excellent by mechanical strength, rigidity at the time of heat, and moldability.

  The polyamide resin (A) may contain a polyamide other than the polyamide (a-1) and the polyamide (a-2). As the polyamide other than the polyamide (a-1) and the polyamide (a-2), Although not particularly limited, for example, polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonanemethylene terephthalamide), polyamide 6I (polyhexamethylene isophthalamide), and copolymerized polyamides containing these as structural components Can be mentioned.

  Although it does not specifically limit as a terminal group of the polyamide used by this invention, Generally an amino group or a carboxyl group exists. The ratio of the amount of amino end groups to the total amount of amino end groups and carboxyl end groups in the polyamide used in the present invention [amino end group amount / (amino end group amount + carboxyl end group amount)] is 0.3 or more and 1 Is preferably less than 0.0, more preferably from 0.3 to 0.8, and even more preferably from 0.3 to 0.6. When the ratio of the terminal group amount is within the above range, the color tone, mechanical strength, and vibration fatigue resistance of the molded product obtained from the polyamide resin composition tend to be more excellent.

  The amount of amino end groups of the polyamide is preferably 10 to 100 μmol / g, more preferably 15 to 80 μmol / g, and further preferably 30 to 80 μmol / g. When the amino terminal group amount is within the above range, the mechanical strength of the polyamide resin composition tends to be more excellent.

Here, as an example of the measuring method of the amount of amino terminal groups and the amount of carboxyl terminal groups in this specification, a < ¹ > H-NMR method and a titration method are mentioned. ^{In the 1} H-NMR method, it can be determined by the integral value of the characteristic signal corresponding to each terminal group. In the titration method, for the amino end group, a method of titrating a polyamide resin phenol solution with 0.1N hydrochloric acid, for the carboxyl end group, a method of titrating a polyamide resin benzyl alcohol solution with 0.1N sodium hydroxide, etc. Is mentioned.

  Furthermore, as a method for adjusting the concentration of the end groups of the polyamide used in the present invention, a known method can be used. Although it does not specifically limit as an adjusting method, For example, the method of using a terminal adjusting agent is mentioned. As a specific example, adding one or more terminal regulators selected from the group consisting of a monoamine compound, a diamine compound, a monocarboxylic acid compound, and a dicarboxylic acid compound so as to have a predetermined terminal concentration during polymerization of polyamide. Is mentioned. The timing of adding the terminal adjuster to the solvent is not particularly limited as long as it functions as a terminal adjuster. For example, the above-described polyamide raw material may be added to the solvent.

  The monoamine compound is not particularly limited, but examples thereof include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. Alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine, and any mixtures thereof. Of these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferable from the viewpoints of reactivity, boiling point, stability of the sealing end and price. These may be used alone or in combination of two or more.

  Although the said diamine compound is not specifically limited, For example, linear aliphatic diamines, such as hexamethylene diamine and pentamethylene diamine; Branched aliphatic diamines, such as 2-methylpentane diamine and 2-ethyl hexamethylene diamine; Aromatic diamines such as p-phenylenediamine and m-phenylenediamine; cycloaliphatic diamines such as cyclohexanediamine, cyclopentanediamine and cyclooctanediamine are listed. These may be used alone or in combination of two or more.

  The monocarboxylic acid compound is not particularly limited, and examples thereof include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyl. Aliphatic monocarboxylic acids such as acids; Alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; Aromatics such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid A monocarboxylic acid etc. are mentioned. In this invention, these carboxylic acid compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  The dicarboxylic acid compound is not particularly limited. For example, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid. Aliphatic dicarboxylic acids such as 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; isophthalic acid 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, diphenylmethane 4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic And unit (units) derived from an aromatic dicarboxylic acid such as 4,4'-biphenyl dicarboxylic acid. These may be used alone or in combination of two or more.

  The polyamide used in the polyamide resin (A) of the present invention has a viscosity number (VN) measured with 96% (mass fraction) sulfuric acid in accordance with ISO 307 and is 100 to 180 ml / g. From the viewpoints of mechanical strength, fluidity during injection molding, and appearance. More preferably, it is 110-150 ml / g.

The polyamide resin (A) of the present invention has at least one melting point below 240 ° C, at least one melting point above 240 ° C, and one crystallization peak temperature.
The crystallization peak temperature is a value measured by differential scanning calorimetry (DSC) in accordance with JIS K7121, similarly to the melting point, and specifically, the crystallization peak temperature when cooled at a cooling rate of 20 ° C./min. That is.

  The melting point of the polyamide resin (A) is preferably at least one at 150 to 238 ° C and at least one at 240 to 320 ° C, at least one at 180 to 235 ° C, and at least one at 240 to 300 ° C. More preferably, at least one at 180-235 ° C, more preferably at least one at 240-280 ° C, particularly at least one at 190-230 ° C, at least one at 240-280 ° C preferable. When at least two melting points are within the above ranges, the mechanical strength and the rigidity under heat, the chemical resistance, and the moldability tend to be excellent.

Although the crystallization peak temperature of a polyamide resin (A) is not specifically limited, 150-240 degreeC is preferable, 160-220 degreeC is more preferable, 170-200 degreeC is further more preferable. When the crystallization peak temperature is within the above range, chemical resistance and molding processability tend to be more excellent. Moreover, when the crystallization peak temperature is one within the above range, it tends to be more excellent in chemical resistance and hydrolysis resistance.
The crystallization peak temperature of the polyamide resin (A) is not less than the crystallization peak temperature of the polyamide (a-1) and not more than the crystallization peak temperature of the polyamide (a-2). It is preferable because it tends to be more excellent in molding processability.

[Production Method of Polyamide Resin (A)]
As a method for producing the polyamide resin (A), a method of kneading the polyamide in a melted state using a single-screw or multi-screw extruder can be used. When using an extruder, the polyamide resin (A) of the present invention can be produced by adjusting the processing temperature and residence time, or using phosphites or metal phosphites. For example, by producing polyamide (a-1) and polyamide (a-2) by adjusting the processing temperature to 290 to 350 ° C. and adjusting the average residence time to be 2 to 10 minutes, at least There is a tendency that a polyamide resin (A) having one melting point in a predetermined temperature range and one crystallization peak temperature can be obtained. The polyamide resin (A) of the present invention is easily obtained as the processing temperature is high, and is easily obtained as the average residence time is increased. On the other hand, by using phosphites and metal phosphites, the polyamide resin (A) can be easily obtained even when the average residence time is short, and the polyamide resin ( A) can be obtained. Moreover, the polyamide resin (A) of this invention can also be obtained simultaneously in the process of obtaining the polyamide resin composition containing the glass fiber mentioned later.

  As phosphites, for example, ethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, diphenyl phosphate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, tris (2 -Ethylhexyl) phosphate, triphenyl phosphate, diphenyl cresyl phosphate, tricresyl phosphate, biphenyl phosphate, tris (2,4-di-t-butylphenyl) phosphate, tris (1,5-di-t-butylphenyl) , Tris (dimethylphenyl), tris (isopropylphenyl) phosphate, octyldiphenylphosphate, or these Mention may be made of the compound.

Examples of the metal phosphite salts include phosphorous acid, hypophosphorous acid, elements 1, 2, 3, 4, 5, 6, 7, 8, 11, 12, 13 and tin of the periodic table. Mention may be made of metal salts with lead and the like. In addition, these metal phosphites may be used alone or in combination of two or more.
The content of these phosphites and metal phosphites is preferably 0.05 to 10 parts by mass, more preferably 0 with respect to 100 parts by mass of the polyamide contained in the polyamide resin (A). 0.1 to 5 parts by mass, and more preferably 0.1 to 2.5 parts by mass.

[Glass fiber (B)]
The polyamide resin composition of the present invention contains glass fiber (B). By containing glass fiber, excellent mechanical strength and rigidity can be obtained.

The glass fiber may have a circular cross section or a flat shape (such as an elliptical shape or a saddle shape). A flat shape is preferable from the viewpoint of low warpage.
When the cross section of the glass fiber is circular, the number average fiber diameter is preferably 3 to 30 μm, more preferably 9 to 20 μm, and still more preferably 12 from the viewpoint of excellent mechanical strength and appearance. ~ 19 μm. On the other hand, in the case of a flat shape, from the viewpoint of excellent mechanical strength, appearance, and low warpage, the average minor axis is preferably 3 to 15 μm, more preferably 4 to 10 μm, and further preferably 5 to 9 μm. .

In the case of a circular shape or a flat shape, an average cross-sectional area of 50 to 350 μm ² is preferable from the viewpoint of excellent mechanical strength and appearance. More preferably from 100 to 300 [mu] m ^2, more preferably from 120 to 250 ^2.

  The specific composition of the glass fiber is not limited to the following, but includes, for example, an E glass (non-alkali glass) composition, a C glass (alkali glass) composition, an S glass (tempered glass) composition, and an alkali resistance. A glass composition etc. are mentioned. Among these, E glass is preferable from the viewpoint of easy availability.

  The glass fiber is not limited to the following, for example, the surface with a silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, etc. It is preferable that it is processed, and the adhesion amount is 0.01 mass% or more with respect to glass fiber mass (total amount of glass fiber and a surface treating agent).

  Furthermore, it can also process with a sizing agent as needed. Examples of the sizing agent include, but are not limited to, for example, carboxylic acid anhydride-containing unsaturated vinyl monomers and unsaturated vinyl monomers excluding the carboxylic acid anhydride-containing unsaturated vinyl monomers; Copolymer, epoxy compound, polyurethane resin, homopolymer of acrylic acid, copolymer of acrylic acid and other copolymerizable monomers, and primary, secondary, and tertiary amines thereof. Of the salt. These may be used individually by 1 type and may be used in combination of 2 or more type.

  In particular, from the viewpoint of mechanical strength of the polyamide resin composition of the present invention, an unsaturated vinyl monomer containing a carboxylic acid anhydride-containing unsaturated vinyl monomer and an unsaturated vinyl monomer excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer; , An epoxy compound and a polyurethane resin, and combinations thereof are preferable, and unsaturated vinyl monomers containing unsaturated vinyl monomers containing carboxylic acid anhydrides and unsaturated vinyl monomers containing carboxylic acid anhydrides are preferred. More preferred are copolymers and polyurethane resins containing vinyl monomers as polymerized units, and combinations thereof.

  Only one type of glass fiber may be used alone, or two or more types having different cross-sectional shapes, average cross-sectional areas, glass compositions, surface treatment agents, sizing agents, etc. may be used in combination.

  Further, the glass fiber may be used in a roving shape, or may be used, for example, as a chopped strand cut to a length of about 2 to 5 mm.

From the viewpoint of mechanical strength and appearance, the length of these glass fibers is preferably 100 to 750 μm in terms of weight average fiber length in a molded product obtained by molding a polyamide resin composition. More preferably, it is 150-500 micrometers, More preferably, it is 200-400 micrometers. The weight average fiber length is measured by, for example, a method in which the molded body is heated and incinerated at a temperature equal to or higher than the decomposition temperature of the polyamide resin composition, and the remaining ash content is photographed using a microscope and the length of the glass fiber is measured. be able to. The following formula (I) is mentioned as a method for calculating the weight average fiber length from the measurement value obtained by the microscopy.
Weight average fiber length = sum of squares of glass fiber length / total of glass fiber length (I)

Examples of additional components are listed below.
Inorganic fillers other than glass fibers, antioxidants, UV absorbers, heat stabilizers, photodegradation inhibitors, plasticizers, lubricants, mold release agents, nucleating agents, flame retardants, colorants, etc. can be added. Other thermoplastic resins may be blended.

The lubricant is not particularly limited, and examples thereof include fatty acid metal salts, fatty acid esters, fatty acid amides, and polyethylene waxes. From the viewpoint of excellent appearance and molding processability, one or more selected from fatty acid metal salts, fatty acid esters, and fatty acid amides are preferable, and two or more types are more preferable, and the fatty acid metal salt and the fatty acid ester are used in combination. More preferably.
Although there is no restriction | limiting in particular in the compounding quantity of these lubricants, From a viewpoint of the outstanding external appearance and moldability, 0.05-1.5 mass% is preferable with respect to 100 mass% of polyamide resin compositions, 0.05-1 % By mass is more preferable, and 0.08 to 0.6% by mass is more preferable.

  Although it does not restrict | limit especially as a coloring agent, For example, carbon black, a titanium oxide, an azine dye etc. are mentioned. Although there is no restriction | limiting in particular in the compounding quantity of these coloring agents, 0.01-3 mass% is preferable from a viewpoint of the outstanding external appearance and moldability, 0.05-2 mass% is more preferable, 0.1-2 More preferred is mass%.

[Production Method of Polyamide Resin Composition]
As a method for producing the polyamide resin composition of the present invention, a method of kneading the polyamide resin in a melted state using a single-screw or multi-screw extruder can be used. When using chopped strand glass fiber, use a twin screw extruder equipped with an upstream supply port and a downstream supply port, and after feeding and melting polyamide resin from the upstream supply port, chopped from the downstream supply port A method of supplying strand glass fibers and melt-kneading can be preferably used. Moreover, also when using glass fiber roving, it can compound by a well-known method.

[Molded body]
The composition thus obtained can be molded as molded parts of various parts by various conventionally known methods such as injection molding.
As these various parts, for example, they can be suitably used for automobiles, machine industries, electrical / electronics, industrial materials, industrial materials, daily products and household products.
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to what was shown by this Example.

(Raw materials used)
(1) Polyamide (1-1) Polyamide 610 (hereinafter abbreviated as PA-1)
Melting point: 220 ° C, crystallization peak temperature: 180 ° C
VN (sulfuric acid): 115 ml / kg, amino end group: 40 mmol / kg,
Carboxylic acid end group: 60 mmol / kg
(1-2) Polyamide 66 (hereinafter abbreviated as PA-2)
Melting point: 260 ° C, crystallization peak temperature: 215 ° C
VN (sulfuric acid): 145 ml / kg, amino end group: 50 mmol / kg,
Carboxylic acid end group: 80 mmol / kg

(2) Glass fiber Glass fiber having an average fiber diameter of 10 μm (hereinafter abbreviated as GF)
(3) Thermal stabilizer A mixture of copper iodide (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter abbreviated as CuI) and potassium iodide (manufactured by Wako Pure Chemical Industries, Ltd., hereinafter abbreviated as KI) in a mass ratio of 1: 5 ( Hereinafter abbreviated as HS)

(4) Lubricant (4-1) Calcium montanate (hereinafter abbreviated as WAX-1)
(4-2) Montanic acid ester (hereinafter abbreviated as WAX-2)

(5) Phosphorous acid compound (5-1) Phosphite ester compound Product name: Irgafos 168 (manufactured by BASF)
(5-2) Metal phosphite calcium hypophosphite (manufactured by Daido Pharmaceutical)
(6) Colorant Product name: Nubian Black (registered trademark) TN-870 (manufactured by Orient Chemical Co., Ltd.)

(Evaluation method)
The evaluation method is described below.
<Melting point, crystallization peak temperature>
Using the differential scanning calorimeter [DSC-7: manufactured by PerkinElmer], the polyamide resin composition pellets obtained in the examples and comparative examples were compliant with JIS K7121, and both the heating rate and the cooling rate were 20 ° C / In minutes, the melting peak temperature and the crystallization peak temperature measured between 50 ° C. and 350 ° C. were measured. Even if glass fiber is included, since the melting point of glass fiber is not within the measurement range, the melting peak temperature and crystallization peak temperature of the polyamide resin composition are regarded as the melting peak temperature and crystallization peak temperature of the polyamide resin. be able to.

<Chemical resistance (calcium chloride resistance)>
Using the injection molding machine [PS-40E: manufactured by Nissei Plastic Co., Ltd.], the polyamide resin composition pellets obtained in the examples and comparative examples were injected and held for 10 seconds, cooled for 15 seconds, and mold temperature. A flat plate molded piece of 130 × 130 × 3 mm was formed at 80 ° C. and a molten resin temperature of 290 ° C. Next, a test piece was obtained by cutting into a strip shape of 130 × 10 × 3 mm in the direction perpendicular to the flow from the center of the flat plate (direction perpendicular to the axis in the flow direction from the gate of the molded product). The obtained test piece was absorbed in water at 80 ° C. for 100 hours. Then, 1) wrap the gauze around the test piece, 2) impregnate the gauze with 40% by weight calcium chloride aqueous solution, 3) apply a load of 20 MPa in cantilever bending stress, and leave it for 1 hour. 4) place it in an oven at 100 ° C. It was exposed for 2 hours, 5) gauze was removed, and it was cooled at room temperature for 1 hour. 6) The presence or absence of cracks was confirmed visually. The cycles of 1) to 6) were repeated until cracks were observed on the surface of the test piece, and the number of cycles at which cracks began to be observed was evaluated.

<Hydrolysis resistance>
Using the injection molding machine [PS-40E: manufactured by Nissei Plastic Co., Ltd.], the polyamide resin composition pellets obtained in the examples and comparative examples were injected and held for 10 seconds, cooled for 15 seconds, and mold temperature. A flat molded piece of 60 × 60 × 3 mm was formed at 80 ° C. and a molten resin temperature of 290 ° C. Next, the test was conducted by cutting the flat plate from the flat plate in the direction perpendicular to the flow direction (perpendicular to the axis in the flow direction from the gate of the molded product) to the shape of a small tensile specimen type 4 according to ISO 8256. I got a piece. The obtained test piece was immersed in pure water / long life coolant liquid (LLC liquid; G48 manufactured by BASF) = 50/50 at 130 ° C. for 24 hours and 500 hours using an autoclave. The test piece after immersion was subjected to a tensile test at a distance between chucks of 30 mm and a tensile speed of 1 mm / min. The tensile strength retention after 500 hours immersion was evaluated against the tensile strength after 24 hours immersion.

[Production Example 1]
Using an autoclave with an internal volume of 5.4 L (manufactured by Nitto Koatsu Co., Ltd.), PA-1 was heated at a ratio of 50 parts by mass and PA-2 at a ratio of 50 parts by mass in a nitrogen atmosphere at 300 ° C. for 1 hour to obtain a polyamide resin. PA-3 was obtained. The melting point was one at 195 ° C and the crystallization peak temperature was one at 133 ° C.

[Examples 1 and 2, Comparative Examples 1 and 2]
L / D (of the cylinder of the extruder) having an upstream supply port in the first barrel from the upstream side of the extruder, a downstream supply port in the ninth barrel, and a vacuum devolatilization port in the 11th barrel Using a twin screw extruder [ZSK-26MC: manufactured by Coperion (Germany)] with length / cylinder diameter of extruder = 48 (barrel number: 12), the temperature from the upstream supply port to the die is set to 320 ° C. Then, polyamide, heat stabilizer, lubricant, phosphite compound, nigrosine are supplied from the upstream supply port so that the ratio shown in Table 1 is achieved at a screw rotation speed of 300 rpm and a discharge rate of 25 kg / h, and supplied downstream. Glass fiber chopped strands were supplied from the mouth, decompressed and melt-kneaded from the vacuum devolatilization mouth, and resin composition pellets were produced in an average residence time of 45 seconds. The obtained resin composition pellets were molded at a resin temperature of 290 ° C. and a mold temperature of 80 ° C. to evaluate chemical resistance and hydrolysis resistance. The physical property values and evaluation results are shown in Table 1 together with the composition.

  As shown in Table 1, the polyamide resin composition of the present invention has drastically improved chemical resistance and excellent strength. Further, when (A) polyamide resin having at least one melting point below 240 ° C. and at least one melting point above 240 ° C. and having a single crystallization peak temperature is used, the chemical resistance of the polyamide resin composition Can be improved.

  Since the polyamide resin composition of the present invention is excellent in chemical resistance, it can be suitably used as a molded product that requires mechanical strength and chemical resistance, such as automobile underhood parts.

Claims (9)

  A polyamide resin composition comprising a polyamide resin (A) and glass fibers (B), wherein the polyamide resin (A) has at least one melting point below 240 ° C, A polyamide resin composition having at least one melting point at 240 ° C. or more and one crystallization peak temperature.   The polyamide resin (A) has a melting point of 240 ° C. or less, a polyamide (a-1) having a carbon number / nitrogen number ratio (C / N ratio) of 7 or more, a melting point of 240 ° C. or more, The polyamide resin composition according to claim 1, comprising a polyamide (a-2) having a carbon number / nitrogen number ratio (C / N ratio) of less than 7.   3. The polyamide (a-1) according to claim 2, comprising 50 mol% or more of units composed of aliphatic diamine and aliphatic dicarboxylic acid and / or units composed of ω-aliphatic aminocarboxylic acid. Polyamide resin composition.   The polyamide (a-1) is selected from the group consisting of polyamide 410, polyamide 412, polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide 1010, polyamide 1012, and copolymerized polyamide containing these as constituent components. The polyamide resin composition according to claim 2, wherein the polyamide resin composition is one or more.   The polyamide resin composition according to any one of claims 2 to 4, wherein the polyamide (a-2) contains 50 mol% or more of a unit composed of an aliphatic diamine and an aliphatic dicarboxylic acid.   The polyamide (a-2) is at least one selected from the group consisting of polyamide 46, polyamide 56, polyamide 66, and a copolymerized polyamide containing these as constituent components. The polyamide resin composition described in 1.   The crystallization peak temperature is not less than the crystallization peak temperature of the polyamide (a-1) and not more than the crystallization peak temperature of the polyamide (a-2). Polyamide resin composition.   The polyamide (a-1) in an amount of 30 to 70% by mass and the polyamide (a-2) in an amount of 30 to 70% by mass with respect to 100% by mass of the polyamide in the polyamide resin (A). The polyamide resin composition according to any one of the above.   Using (A) polyamide resin having at least one melting point below 240 ° C. and at least one melting point above 240 ° C. and having a single crystallization peak temperature, the (A) polyamide resin and (B) A method for improving chemical resistance of a polyamide resin composition comprising glass fibers.