WO2018123563A1 - Polyamide resin composition, method for producing same and molded body formed from same - Google Patents

Abstract

A polyamide resin composition which is characterized by containing 100 parts by mass of a polyamide (A) that has a melting point of 270-350°C and 10-80 parts by mass of a phosphorus flame retardant (B), and which is also characterized by having a degree of yellowing (YI₀) of 3.0 or less.

Description

Polyamide resin composition, method for producing the same, and molded article comprising the same

The present invention relates to a polyamide resin composition, a method for producing the same, and a molded body comprising the same.

Polyamide is excellent in heat resistance and mechanical properties, and is used as a constituent material for many electric / electronic parts and parts around automobile engines.
Among these parts, polyamides constituting electric / electronic parts are required to have high flame retardancy. As a method for imparting flame retardancy to the resin, it is usual to use a flame retardant. In recent years, due to the increase in environmental awareness, halogen-based flame retardants have been avoided, and the use of non-halogen-based flame retardants is common.

As the non-halogen flame retardant, for example, Patent Document 1 discloses a mixture of a reaction product of melamine and phosphoric acid, a zinc compound, and a phosphinate, and Patent Document 2 discloses a reaction of melamine and phosphoric acid. Mixtures of products, phosphinates and metal compounds are disclosed, all of which are disclosed to satisfy the flame retardant standard UL94V-0 standard in 1/16 inch molded articles.
However, the phosphinic acid salt may be decomposed when it is melt-kneaded with polyamide to produce a resin composition, and the gas generated at that time also decomposes the polyamide, resulting in a decrease in the molecular weight of the polyamide. The obtained resin composition has a problem that heat resistance, mechanical properties, flame retardancy, and the like are deteriorated. Further, the polyamide is thermally deteriorated and oxidized to be thermally discolored, and yellowness (yellow index, YI). ) May have risen.

JP 2004-263188 A JP 2007-023206 A

The present invention solves the above-described problems, and an object of the present invention is to provide a polyamide resin composition that is excellent in heat resistance, mechanical properties, and flame retardancy and in which an increase in yellowness is suppressed.

As a result of intensive studies to solve the above problems, the present inventors have found that a polyamide resin composition produced under specific conditions can solve the above problems, and have reached the present invention.
That is, the gist of the present invention is as follows.
(1) It contains 100 parts by mass of polyamide (A) having a melting point of 270 to 350 ° C. and 10 to 80 parts by mass of a phosphorus-based flame retardant (B), and has a yellowness (YI ₀ ) of 3.0 or less. A polyamide resin composition characterized by the above.
(2) The polyamide resin composition according to (1), wherein the yellowness change value (ΔYI) after reflow treatment at 265 ° C. is 12.0 or less.
(3) The polyamide resin composition according to (1) or (2), wherein the phosphorus-based flame retardant (B) is a phosphinate and / or a diphosphinate.
(4) The polyamide resin according to (3), wherein the phosphinic acid salt is a compound represented by the following general formula (I) and the diphosphinic acid salt is a compound represented by the following general formula (II): Composition.

(Wherein R ¹ , R ² , R ⁴ and R ⁵ each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms or a phenyl group. R ³ represents a linear or branched group. The chain represents an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylalkylene group, or an alkylarylene group, and M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. Is 1 or 3. n, a, and b are integers satisfying the relational expression 2 × b = n × a.)
(5) The polyamide resin composition according to any one of (1) to (4), further comprising 5 to 140 parts by mass of a fibrous reinforcing material (C).
(6) The polyamide resin composition according to any one of (1) to (5), further containing 0.1 to 20 parts by mass of talc (F).
(7) A method for producing the polyamide resin composition according to any one of (1) to (6) above, wherein in the melt-kneading of polyamide (A) and phosphorus flame retardant (B), melt-kneading One or more side feeders are installed in the machine, and the phosphorus-based flame retardant (B) is added in an amount of 20 parts by mass or less per 100 parts by mass of the polyamide (A) per side feeder. A method for producing a polyamide resin composition, comprising adding a flame retardant (B) from a side feeder.
(8) A method for producing the polyamide resin composition as described in (5) above, wherein the fibrous reinforcing material (C) is added in a plurality of times in the melt-kneading of the resin composition. A method for producing a polyamide resin composition.
(9) The method for producing a polyamide resin composition according to (7) or (8), wherein the polyamide (A) is polymerized before melt kneading and the polymerization is carried out in an inert gas atmosphere. .
(10) The polyamide resin composition according to any one of (7) to (9), wherein the melt kneading of the polyamide (A) and the phosphorus-based flame retardant (B) is performed in an inert gas atmosphere. Manufacturing method.
(11) A molded article obtained by molding the polyamide resin composition according to any one of (1) to (6) above.

According to the present invention, there is provided a polyamide resin composition in which thermal deterioration during melt kneading and thermal discoloration due to oxidative deterioration are greatly suppressed, and decomposition of polyamide is suppressed, and mechanical properties and flame retardancy are maintained at a high level. Can be provided. Moreover, the molded object formed by shape | molding the polyamide resin composition of this invention can suppress the raise of yellowness, even if the reflow process from which the maximum temperature will be about 260 degreeC is carried out.

Hereinafter, the present invention will be described in detail.
The polyamide resin composition of the present invention contains polyamide (A) and a phosphorus-based flame retardant (B).

The polyamide (A) constituting the polyamide resin composition of the present invention needs to have a melting point of 270 ° C. to 350 ° C. Since the polyamide (A) has a melting point of 270 ° C. or higher, it has heat resistance and can withstand a reflow process in which the maximum temperature is about 260 ° C. On the other hand, when the melting point of the polyamide (A) exceeds 350 ° C., the decomposition temperature of the amide bond is about 350 ° C., so that carbonization and decomposition may proceed during melt processing.

Examples of the polyamide (A) include aliphatic polyamides, semi-aromatic polyamides, alicyclic polyamides, and copolymers thereof from the classification of monomer components.
Specific examples of the aliphatic polyamide include polyamide 46 and the like.
Semi-aromatic polyamides include polyamides composed of an aromatic dicarboxylic acid component and an aliphatic diamine component. Specific examples include polyamide 4I (I: isophthalic acid), polyamide 6I, polyamide 7T (T: terephthalic acid). ), Polyamide 8T, polyamide 9T, polyamide 10T, polyamide 11T, polyamide 12T, and the like.
Specific examples of the alicyclic polyamide include polyamide 6C (C: 1,4-cyclohexanedicarboxylic acid), polyamide 7C, polyamide 8C, polyamide 9C, polyamide 10C, polyamide 11C, and polyamide 12C.
Further, as the copolymer, for example, when the diamine has 6 carbon atoms, PA6T / 6, PA6T / 12, PA6T / 66, PA6T / 610, PA6T / 612, PA6T / 6I, PA6T / 6I / 66, PA6T / M5T (M5: methylpentadiamine), PA6T / TM6T (TM6: 2,2,4- or 2,4,4-trimethylhexamethylenediamine), PA6T / MMCT (MMC: 4,4'-methylenebis (2-methyl) Cyclohexylamine)) and the like.
As the polyamide (A), these polyamides may be used alone, or a copolymer or a mixture of two or more kinds of polyamides may be used.
In the present invention, as polyamide (A), because of its high industrial versatility, polyamide 46, polyamide 6T, polyamide 9T, polyamide 10T, and copolymers thereof are preferred examples. Further, polyamide 6T, polyamide 9T, polyamide 10T, and copolymers thereof are more preferable because they are particularly excellent in reflow resistance from the viewpoint of high heat resistance and low water absorption, and polyamide 10T and copolymers thereof are particularly preferable. preferable.

In the present invention, the polyamide (A) preferably contains a monocarboxylic acid component as a constituent component. By containing a monocarboxylic acid, the polyamide (A) can keep the amount of free amino groups at the terminal low, and can suppress degradation and discoloration of the polyamide due to thermal degradation and oxidative degradation when receiving heat. . As a result, the mechanical properties and flame retardancy are highly maintained.

The content of the monocarboxylic acid component is preferably 0.3 to 4.0 mol%, and preferably 0.3 to 3.0 mol%, based on all monomer components constituting the polyamide (A). More preferably, it is 0.3 to 2.5 mol%, more preferably 0.8 to 2.5 mol%. By containing a monocarboxylic acid component within the above range, the polyamide (A) can be prevented from being decomposed or discolored due to thermal deterioration or oxidative deterioration when subjected to heat, and the molecular weight distribution during polymerization can be reduced. In addition, the mold releasability is improved during the molding process, and the amount of gas generated can be suppressed during the molding process. On the other hand, when the content of the monocarboxylic acid component exceeds the above range, the mechanical properties of the polyamide (A) may deteriorate. In the present invention, the content of the monocarboxylic acid refers to the proportion of the monocarboxylic acid residue in the polyamide (A), that is, the proportion of the monocarboxylic acid from which the terminal hydroxyl group is eliminated.

In the present invention, the molecular weight of the monocarboxylic acid component is preferably 140 or more, and more preferably 170 or more. When the molecular weight of the monocarboxylic acid is 140 or more, the polyamide (A) can be prevented from being decomposed or discolored due to thermal degradation or oxidative degradation when receiving heat, and improved in mold release properties. The amount of gas generated can be suppressed at the temperature, and the molding fluidity can be improved.
Examples of the monocarboxylic acid component include aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, and aromatic monocarboxylic acids, and among them, aliphatic monocarboxylic acids are preferable.
Examples of the aliphatic monocarboxylic acid having a molecular weight of 140 or more include caprylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid. Of these, stearic acid is preferred because of its high versatility.
Examples of the alicyclic monocarboxylic acid having a molecular weight of 140 or more include 4-ethylcyclohexanecarboxylic acid, 4-hexylcyclohexanecarboxylic acid, and 4-laurylcyclohexanecarboxylic acid.
Examples of the aromatic monocarboxylic acid having a molecular weight of 140 or more include 4-ethylbenzoic acid, 4-hexylbenzoic acid, 4-laurylbenzoic acid, 1-naphthoic acid, 2-naphthoic acid and derivatives thereof. .
The monocarboxylic acid component may be used alone or in combination. A monocarboxylic acid having a molecular weight of 140 or more and a monocarboxylic acid having a molecular weight of less than 140 may be used in combination.
In the present invention, the molecular weight of the monocarboxylic acid refers to the molecular weight of the starting monocarboxylic acid.

Generally, it is known that a polymer has a crystalline phase and an amorphous phase, and crystal characteristics such as a melting point are determined solely by the state of the crystalline phase. Since the terminal group in the polymer exists in an amorphous phase, the melting point of the polyamide does not change depending on the presence / absence and type of the terminal group. Since the monocarboxylic acid bonded to the end of the polyamide chain is also present in the amorphous phase, the melting point of the polyamide is not lowered by the inclusion of the monocarboxylic acid.

In the present invention, the polyamide (A) has a melt flow rate (MFR) at 340 ° C. and a load of 1.2 kg of preferably 1 to 200 g / 10 minutes, more preferably 10 to 150 g / 10 minutes. More preferably, it is 20 to 100 g / 10 minutes. MFR can be used as an index of molding fluidity, and the higher the MFR value, the higher the fluidity. When the MFR of the polyamide (A) exceeds 200 g / 10 minutes, the mechanical properties of the resulting resin composition may be deteriorated. When the MFR of the polyamide (A) is less than 1 g / 10 minutes, the fluidity may be reduced. It is extremely low and may not be melt processed.

The polyamide (A) can be produced using a conventionally known method such as a heat polymerization method or a solution polymerization method. Of these, the heat polymerization method is preferably used because it is industrially advantageous. The polymerization of the polyamide (A) is preferably carried out in an inert gas atmosphere with an inert gas such as nitrogen, carbon dioxide, or argon sealed in a polymerization vessel. Thereby, discoloration due to oxidative degradation of the polyamide during polymerization can be suppressed, and at the same time, discoloration in the process after polymerization can be suppressed.

In the production of polyamide (A), a polymerization catalyst may be used to increase the efficiency of polymerization. Examples of the polymerization catalyst include phosphoric acid, phosphorous acid, hypophosphorous acid or salts thereof, and the addition amount of the polymerization catalyst is usually 2 mol% or less based on the total mol of dicarboxylic acid and diamine. It is preferable that

Examples of the phosphorus-based flame retardant (B) constituting the polyamide resin composition of the present invention include phosphate ester compounds, phosphinates, diphosphinates, phosphazene compounds, and the like.

Examples of phosphoric acid ester compounds include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, tri (2-ethylhexyl). ) Phosphate, diisopropylphenyl phosphate, trixylenyl phosphate, tris (isopropylphenyl) phosphate, trinaphthyl phosphate, bisphenol A bisphosphate, hydroquinone bisphosphate, resorcin bisphosphate, resorcinol-diphenyl phosphate, trioxybenzene triphosphate, or these Examples include substitution products and condensates . Among these, a phosphoric acid ester compound is preferable because it hardly adheres to the mold and is excellent in heat resistance and moisture resistance of the molded body. The phosphate ester compound may be a monomer, an oligomer, a polymer, or a mixture thereof. Specific product names of the phosphate ester compounds include, for example, “TPP” [triphenyl phosphate], “TXP” [trixylenyl phosphate], “CR-733S” [resorcinol bis ( Diphenyl phosphate)], “PX200” [1,3-phenylene-teslakis (2,6-dimethylphenyl) phosphate], “PX201” [1,4-phenylene-tetrakis (2,6-dimethylphenyl) phosphate Ester], “PX202” [4,4′-biphenylene-teslakis (2,6-dimethylphenyl) phosphate]. These may be used alone or in combination.

Examples of the phosphinate and diphosphinate include compounds represented by the following general formula (I) and general formula (II), respectively.

In the formula, each of R ¹ , R ² , R ⁴ and R ⁵ independently needs to be a linear or branched alkyl group having 1 to 16 carbon atoms or a phenyl group, and has 1 to 8 carbon atoms. Are preferably an alkyl group or a phenyl group, and are a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an n-pentyl group, an n-octyl group, or a phenyl group. More preferred is an ethyl group. R ¹ and R ² and R ⁴ and R ⁵ may form a ring with each other.
R ³ must be a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkyl alkylene group, or an alkyl arylene group. Examples of the linear or branched alkylene group having 1 to 10 carbon atoms include methylene group, ethylene group, n-propylene group, isopropylene group, isopropylidene group, n-butylene group, tert-butylene group, n- A pentylene group, an n-octylene group, and an n-dodecylene group may be mentioned. Examples of the arylene group having 6 to 10 carbon atoms include a phenylene group and a naphthylene group. Examples of the alkylarylene group include a methylphenylene group, an ethylphenylene group, a tert-butylphenylene group, a methylnaphthylene group, an ethylnaphthylene group, and a tert-butylnaphthylene group. Examples of the arylalkylene group include a phenylmethylene group, a phenylethylene group, a phenylpropylene group, and a phenylbutylene group.
M represents a metal ion. Examples of the metal ions include calcium ions, aluminum ions, magnesium ions, and zinc ions. Aluminum ions and zinc ions are preferable, and aluminum ions are more preferable.
m and n represent the valence of the metal ion. m is 2 or 3. a represents the number of metal ions, and b represents the number of diphosphinic acid ions. n, a, and b are integers satisfying “2 × b = n × a”.

Phosphinates and diphosphinates are produced in aqueous solutions using the corresponding phosphinic acid or diphosphinic acid salt and metal carbonate, metal hydroxide or metal oxide, respectively, and usually exist as monomers, Depending on the reaction conditions, it may be present in the form of a polymeric phosphinate having a degree of condensation of 1 to 3.

Examples of the phosphinic acid used for producing the phosphinic acid salt include dimethylphosphinic acid, ethylmethylphosphinic acid, diethylphosphinic acid, methyl-n-propylphosphinic acid, isobutylmethylphosphinic acid, octylmethylphosphinic acid, methylphenylphosphinic acid, Examples thereof include diphenylphosphinic acid, among which diethylphosphinic acid is preferable.

Specific examples of the phosphinic acid salt represented by the general formula (I) include, for example, calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, ethylmethylphosphine. Magnesium oxide, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, methyl-n-propylphosphine Magnesium acetate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, methylphenylphosphinic acid calcium , Magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, and zinc diphenylphosphinate. Of these, aluminum diethylphosphinate and zinc diethylphosphinate are preferable, and aluminum diethylphosphinate is more preferable because of excellent balance between flame retardancy and electrical characteristics.

In addition, examples of diphosphinic acid used in the production of diphosphinic acid salts include methanodi (methylphosphinic acid) and benzene-1,4-di (methylphosphinic acid).

Specific examples of the diphosphinic acid salt represented by the general formula (II) include, for example, calcium methanedi (methylphosphinate), methanedi (methylphosphinic acid) magnesium, methanedi (methylphosphinic acid) aluminum, and methanedi (methylphosphinic acid). ) Zinc, benzene-1,4-di (methylphosphinic acid) calcium, benzene-1,4-di (methylphosphinic acid) magnesium, benzene-1,4-di (methylphosphinic acid) aluminum, benzene-1,4 -Di (methylphosphinic acid) zinc. Among these, methanedi (methylphosphinic acid) aluminum and methanedi (methylphosphinic acid) zinc are preferable because of excellent balance between flame retardancy and electrical characteristics.

As the phosphorus-based flame retardant (B), a phosphinic acid salt or a diphosphinic acid salt is preferable because it is excellent in miscibility with the polyamide (A) and can effectively impart flame retardancy with a small amount of addition. Furthermore, mixtures of phosphinates or diphosphinates are particularly preferred. Examples of combinations of phosphinic acid salts and diphosphinic acid salts include phosphinic acid salts such as aluminum diethylphosphinate and zinc diethylphosphinate, and diphosphinic acid salts such as methanedi (methylphosphinic acid) aluminum and methanedi (methylphosphinic acid) zinc. Is mentioned. Specific product names of phosphinates, diphosphinates, and mixtures thereof include, for example, “Exolit OP1230”, “Exolit OP1240”, “Exolit OP1312”, “Exolit OP1314”, “Exolit OP1400” manufactured by Clariant. Is mentioned.

Examples of the phosphazene compound include cyclic phosphazene compounds represented by the following general formula (III).

In the formula, R ⁶ and R ⁷ each independently represents an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, and c represents an integer of 3 to 15; Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various hexyl groups, various octyl groups, a cyclopentyl group, and a cyclohexyl group. R ⁶ and R ⁷ may be linear, branched or cyclic. Examples of the aryl group having 6 to 15 carbon atoms include a phenyl group into which a substituent such as an alkyl group, an aryl group, or an alkoxy group may be introduced on the ring. R ⁶ and R ⁷ are preferably both aryl groups, and particularly preferably both phenyl groups. Specific trade names of phosphazene compounds include, for example, “Ravitor FP-100” and “Ravitor FP-110” manufactured by Fushimi Pharmaceutical Co., Ltd., “SPS-100” and “SPB-100” manufactured by Otsuka Chemical Co., Ltd. .

The phosphorus-based flame retardant (B) may be used in combination with the flame retardant aid (D). Examples of the flame retardant aid (D) include nitrogen-based flame retardants and inorganic flame retardants, among which nitrogen-based flame retardants are preferable.

Nitrogen flame retardants include, for example, melamine cyanurate, melamine polyphosphate, melamine pyrophosphate, melamine phosphate, dimelamine pyrophosphate, melam polyphosphate, melem polyphosphate, among which phosphinates and diphosphinates Because of its high combined effect, melamine polyphosphate is preferred. The number of phosphorus is preferably 2 or more, and more preferably 10. The content ratio of the phosphinate or diphosphinate to the melamine polyphosphate is preferably 1: 1 to 8: 1, more preferably 2: 1 to 4: 1 in terms of mass ratio.

Examples of the inorganic flame retardant include metal hydroxides such as magnesium hydroxide, calcium hydroxide and calcium aluminate, and other zinc salts such as zinc borate and zinc phosphate. Among these, a mixture of two or more of zinc borate and other zinc salts is preferable, and a mixture of magnesium hydroxide, zinc borate, and zinc phosphate is more preferable.

The zinc borate, for _{example, 2ZnO · 3B 2 O 3,} 4ZnO · B 2 O 3 · H 2 O, include _{2ZnO · 3B 2 O 3 · 3.5H} 2 O.
Examples of other zinc salts include zinc phosphates such as Zn ₃ (PO ₄ ) ₂ .ZnO, zinc stannates such as ZnSn (OH) ₆ and ZnSnO ₃ , and other calcium zinc molybdates. Zinc phosphate is preferred.
When zinc borate and zinc phosphate are used in combination, the content ratio of zinc borate and zinc phosphate is preferably 1: 0.1 to 1: 5 by mass ratio, and 1: 2 to 1: 4. It is more preferable that the ratio is 1: 2.5 to 1: 3.5.

The metal hydroxide may be granular, plate-like or needle-like. When a granular or plate-like material is used, the average particle size is preferably 0.05 to 10 μm, more preferably 0.1 to 5 μm. When a needle-shaped material is used, the average diameter is preferably 0.01 to 10 μm, more preferably 0.1 to 5 μm, and the average length is preferably 5 to 2000 μm. More preferably, it is ˜1000 μm. The metal hydroxide is preferably a metal hydroxide having a low content of other metals and impurities such as chlorine and sulfur from the viewpoint of heat resistance. In addition, the surface of the metal hydroxide is preferably surface-treated with a surface treatment agent, a solid solution, or the like, since dispersibility in the polyamide resin composition can be improved and thermal stability can be improved. Examples of the surface treating agent include silane coupling agents, titanium coupling agents, fatty acids and derivatives thereof. Examples of the solid solution include metals such as nickel.

In the polyamide resin composition of the present invention, the flame retardant aid (D) may be used alone or in combination.

The content of the phosphorus-based flame retardant (B) in the polyamide resin composition needs to be 10 to 80 parts by mass, and 20 to 40 parts by mass with respect to 100 parts by mass of the polyamide (A). preferable. When the content of the phosphorus-based flame retardant (B) is less than 10 parts by mass, it becomes difficult to impart flame retardancy. On the other hand, when the content of the phosphorus-based flame retardant (B) exceeds 80 parts by mass, it becomes difficult to melt and knead the resin composition, and the obtained resin composition is excellent in flame retardancy but has mechanical characteristics. It becomes insufficient.

The polyamide resin composition of the present invention is one in which thermal deterioration during melt-kneading and thermal discoloration due to oxidative deterioration is greatly suppressed, and the yellowness (YI ₀ ) needs to be 3.0 or less, It is preferably -10.0 to -1.0, and more preferably -10.0 to -5.0. As will be described later, the polyamide resin composition in which the thermal discoloration during melt-kneading is greatly suppressed and the yellowness (YI ₀ ) is 3.0 or less is composed of polyamide (A) and phosphorus flame retardant (B). In melt-kneading, it can be produced by limiting the amount of the phosphorus-based flame retardant (B) added to the polyamide (A).
In addition, the molded product obtained by molding the polyamide resin composition of the present invention has excellent heat discoloration, and since the decomposition of the polyamide is suppressed even when the molded product is heated, yellowing is suppressed. The yellowness change value (ΔYI) after the reflow treatment at 265 ° C. is preferably 12.0 or less. When the yellowness change value (ΔYI) after the reflow treatment at 265 ° C. is 12.0 or less, the resin composition can suppress discoloration during the mounting process of the electric / electronic component.

The polyamide resin composition of the present invention preferably further contains a fibrous reinforcing material (C). The fibrous reinforcing material (C) is not particularly limited. For example, glass fiber, carbon fiber, boron fiber, asbestos fiber, polyvinyl alcohol fiber, polyester fiber, acrylic fiber, wholly aromatic polyamide fiber, polybenzoxazole fiber, poly Tetrafluoroethylene fiber, kenaf fiber, bamboo fiber, hemp fiber, bagasse fiber, high strength polyethylene fiber, alumina fiber, silicon carbide fiber, potassium titanate fiber, brass fiber, stainless steel fiber, steel fiber, ceramic fiber, basalt fiber, etc. Can be mentioned. Among these, glass fiber, carbon fiber, and metal fiber are preferable because they have a high effect of improving mechanical properties, have heat resistance that can withstand the heating temperature during melt kneading with a polyamide resin, and are easily available. The fibrous reinforcing material (C) may be used alone or in combination.

The glass fiber and carbon fiber are preferably surface-treated with a silane coupling agent. The silane coupling agent may be dispersed in the sizing agent. Examples of the silane coupling agent include vinyl silanes, acrylic silanes, epoxy silanes, and amino silanes. Among them, since the adhesion effect between polyamide and glass fibers or carbon fibers is high, amino silane coupling agents are used. preferable.

The fiber length and fiber diameter of the fibrous reinforcing material are not particularly limited, but the fiber length is preferably 0.1 to 7 mm, more preferably 0.5 to 6 mm. Since the fibrous reinforcing material has a fiber length of 0.1 to 7 mm, the resin composition can be reinforced without adversely affecting the moldability. The fiber diameter is preferably 3 to 20 μm, more preferably 5 to 13 μm. Since the fibrous reinforcing material has a fiber diameter of 3 to 20 μm, the resin composition can be reinforced without breaking during melt-kneading. Examples of the cross-sectional shape of the fibrous reinforcing material include a circular shape, a rectangular shape, an oval shape, and other irregular cross-sections. Among them, a circular shape is preferable.

The content of the fibrous reinforcing material (C) in the polyamide resin composition is preferably 5 to 140 parts by mass and more preferably 40 to 80 parts by mass with respect to 100 parts by mass of the polyamide (A). If the content of the fibrous reinforcing material is less than 10 parts by mass, the effect of improving the mechanical properties may be small. On the other hand, when the content of the fibrous reinforcing material exceeds 140 parts by mass, the polyamide resin composition is saturated with the improvement effect of mechanical properties, and not only the improvement effect can be expected, but also the work at the time of melt kneading It may be difficult to obtain pellets due to a decrease in properties.

The polyamide resin composition of the present invention can be further improved in stability and moldability by containing a phosphorus-based antioxidant (E).

The phosphorus antioxidant may be an inorganic compound or an organic compound. Examples of the phosphorus antioxidant include inorganic phosphates such as monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite, Phenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, trinonylphenyl phosphite, diphenylisodecyl phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite (" ADEKA STAB PEP-36 "), bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite (" ADEKA STAB PEP-24G "), tris (2,4-di-tert-butylphenyl) phosphite, Distearyl pentaerythritol Phosphite (“Adekastab PEP-8”), bis (nonylphenyl) pentaerythritol diphosphite (“Adekastab PEP-4C”), 1,1′-biphenyl-4,4′-diylbis [bisphosphonite (2 , 4-di-tert-butylphenyl)], tetrakis (2,4-di-tert-butylphenyl) 4,4'-biphenylene-di-phosphonite ("Hostanox P-EPQ"), tetra (tridecyl-4 Organic phosphorus compounds such as 2,4'-isopropylidene diphenyl diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, etc. It may be used in combination.

The phosphorus-based antioxidant (E) is easily mixed with the phosphorus-based flame retardant (B) uniformly and can prevent the decomposition of the flame retardant, thereby improving the flame retardancy. Moreover, the molecular weight fall of a polyamide (A) can be prevented and the operativity at the time of an extrusion process, a moldability, and a mechanical characteristic can be improved. In particular, a remarkable effect can be exhibited in reducing the degree of discoloration during the reflow process.

The content of the phosphorus-based antioxidant (E) is preferably 0.1 to 3 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the polyamide (A). By setting the content of the phosphorus-based antioxidant (E) to 0.1 to 3 parts by mass, the stability from the extrusion process, the moldability, and the mechanical properties can be reduced without deteriorating the mold during molding. The mold release property can be improved, clogging of the mold gas vent port can be suppressed, and the continuous injection moldability can be improved.

The molded body formed by molding the polyamide resin composition of the present invention can suppress an increase in yellowness even after reflow treatment in which the maximum temperature is about 260 ° C. By containing talc (F), it is possible to suppress the generation of blisters during the reflow process. Talc (F) is not particularly limited, but the average particle size is preferably 10 to 30 μm. In addition, talc (F) may be surface-treated with an organic compound such as a silane coupling agent, and the surface treatment improves the adhesion with polyamide (A), thereby improving strength and suppressing blistering. effective. The average particle diameter of talc (F) in the present invention refers to the median diameter (D50) obtained by the laser diffraction method.

The polyamide resin composition of the present invention may further contain additives such as other fillers and stabilizers as necessary. Examples of additives include swellable clay minerals, silica, alumina, glass beads, graphite and other fillers, pigments such as titanium oxide and carbon black, hindered phenol antioxidants, sulfur antioxidants, and light stabilizers. Agents and antistatic agents.

The method for producing the polyamide resin composition of the present invention by mixing the polyamide (A) and the phosphorus-based flame retardant (B) and further blending the fibrous reinforcing material (C) and other additives, etc. The method is not particularly limited as long as the effect is not impaired, but a melt-kneading method is preferable. Examples of the melt-kneading method include a method using a batch kneader such as Brabender, a Banbury mixer, a Henschel mixer, a helical rotor, a roll, a single screw extruder, a twin screw extruder and the like. The melt kneading temperature is selected from a region where the polyamide resin melts and does not decompose. If the kneading temperature is too high, not only the polyamide (A) is decomposed but also the phosphorus-based flame retardant (B) may be decomposed, so that the melting point (Tm) of the polyamide (A) is (Tm). It is preferably −20 ° C.) to (Tm + 50 ° C.).

When producing the resin composition of the present invention by melt-kneading, it is necessary to limit the amount of the phosphorus-based flame retardant (B) added to the polyamide (A). When a large amount of the phosphorus-based flame retardant (B) is added to the polyamide (A) during the melt-kneading of the polyamide (A) and the phosphorus-based flame retardant (B), the temperature of the resin composition temporarily decreases rapidly. In addition, the viscosity increases rapidly, and a large shear is applied. As a result, the actual temperature of the resin composition becomes higher than the set temperature of the apparatus, and there is a possibility that organic components such as the phosphorus-based flame retardant (B) are decomposed or thermally discolored.
As a method for limiting the amount of the phosphorus-based flame retardant (B) supplied to the polyamide (A), for example, when using a continuous melt kneader, one or more side feeders are installed in the melt kneader, The method of restrict | limiting the addition amount of the phosphorus flame retardant (B) per feeder place is mentioned. In the present invention, the phosphorus-based flame retardant (B) is added so that the addition amount of the phosphorus-based flame retardant (B) per one side feeder is 20 parts by mass or less with respect to 100 parts by mass of the polyamide (A). It is necessary to add from the side feeder.
In addition, as a method for limiting the amount of the phosphorus-based flame retardant (B) supplied to the polyamide (A), when a batch mixer is used as the melt-kneader, a method of supplying it in a plurality of times can be mentioned. The addition amount of the phosphorus-based flame retardant (B) per one time is preferably 20 parts by mass or less with respect to 100 parts by mass of the polyamide (A).
Also in the production of the resin composition containing the fibrous reinforcing material (C), it is preferable to add the fibrous reinforcing material (C) in a plurality of times in the melt-kneading of the resin composition. The amount of the reinforcing material (C) added is preferably 30 parts by mass or less with respect to 100 parts by mass of the polyamide (A).
By limiting the amount of phosphorus flame retardant (B) or fibrous reinforcing material (C) to be added to the polyamide (A), an excessive increase in the actual temperature of the resin composition is suppressed, and heat during melt kneading is suppressed. Discoloration due to deterioration and oxidative deterioration can be suppressed, and discoloration due to thermal deterioration and oxidative deterioration can also be suppressed in a molded body obtained from a resin composition.

In the melt-kneading of the resin composition, an inert gas such as nitrogen, carbon dioxide, or argon can be enclosed in the whole from the raw material supply unit to the heating unit of the machine base and melt-kneaded in an inert gas atmosphere. preferable. Thereby, discoloration due to oxidative deterioration of organic components such as polyamide (A) and various surface treatment agents during melt-kneading can be suppressed, and at the same time, discoloration in the process after melt-kneading can be suppressed.

The resin composition can be processed into various shapes by extruding the molten mixture into strands to form pellets, hot-cutting or underwater cutting the molten mixture into pellets, or extruding into sheets. Examples include a cutting method and a method of extruding and pulverizing into a block shape to form a powder.

The molded article of the present invention is formed by molding the polyamide resin composition of the present invention.
Examples of the molding method of the polyamide resin composition of the present invention include an injection molding method, an extrusion molding method, a blow molding method, and a sintering molding method. A molding method is preferred.
Although it does not specifically limit as an injection molding machine, For example, a screw in-line type injection molding machine or a plunger type injection molding machine is mentioned. The polyamide resin composition heated and melted in the cylinder of the injection molding machine is weighed for each shot, injected into the mold in a molten state, cooled to a predetermined shape and solidified, and then as a molded body from the mold. It is taken out. The resin temperature at the time of injection molding is preferably not less than the melting point (Tm) of the polyamide resin (A) and less than (Tm + 50 ° C.).
Even when a polyamide resin composition is molded, an inert gas such as nitrogen, carbon dioxide, or argon is enclosed in the entire part from the raw material supply unit to the heating unit of the machine base and molded in an inert gas atmosphere. Is preferred. Thereby, discoloration due to oxidative degradation of organic components such as polyamide (A) and various surface treatment agents during molding can be suppressed, and at the same time, discoloration can be suppressed in the steps after the molding step.
In addition, when the polyamide resin composition is heated and melted, it is preferable to use a sufficiently dried polyamide resin composition pellet. If the water content is large, the resin foams in the cylinder of the injection molding machine, and it may be difficult to obtain an optimal molded body. The moisture content of the polyamide resin composition pellets used for injection molding is preferably less than 0.3 parts by mass and more preferably less than 0.1 parts by mass with respect to 100 parts by mass of the polyamide resin composition.

Since the polyamide resin composition of the present invention is excellent in heat discoloration in addition to mechanical properties, heat resistance and flame retardancy, the molded product has a wide range of applications such as automobile parts, electric / electronic parts, sundries, civil engineering and building supplies. Can be used for various purposes. Especially, since the polyamide resin composition of this invention is excellent in a flame retardance, it can be used suitably for an electrical / electronic component. Examples of the electrical / electronic components include connectors, LED reflectors, switches, sensors, sockets, capacitors, jacks, fuse holders, relays, coil bobbins, breakers, electromagnetic switches, holders, and plugs. Moreover, it can be used suitably also for the housing | casing components of an electric equipment represented by OA apparatus, such as a portable personal computer, a resistor, IC, and the housing of LED.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

1. Measuring method The physical properties of the polyamide resin composition were measured by the following methods.

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

(2) Melt flow rate (MFR)
According to JIS K7210, the measurement was performed using a polyamide resin composition pellet at 340 ° C. and a load of 1.2 kg.
MFR can be used as an index of molding fluidity, and the higher the MFR value, the higher the fluidity.

(3) Mechanical properties The polyamide resin composition is injection molded using an injection molding machine (S2000i-100B type manufactured by FANUC) under conditions of cylinder temperature (melting point + 25 ° C.) and mold temperature (melting point-185 ° C.). Thus, a test piece (dumbbell piece) was produced.
Using the obtained test piece, bending strength and bending elastic modulus were measured according to ISO178.
Bending strength and bending elastic modulus indicate that the larger the value, the better the mechanical properties.

(4) Flame retardancy Using an injection molding machine (CND15 manufactured by Niigata Machine Techno Co., Ltd.) under conditions of cylinder temperature (melting point + 25 ° C.) and mold temperature (melting point−185 ° C.), 5 inches (127 mm) × 1 / A 2 inch (12.7 mm) x 1/32 inch (0.79 mm) test piece was prepared.
Using the obtained test piece, evaluation was performed in accordance with the standards of UL94 shown in Table 1 (standards defined by Under Writers Laboratories Inc., USA). When not satisfying any of the standards, it was set as “not V-2”.
A shorter total afterflame time indicates better flame retardancy.

(5) Yellowness (yellow index, YI), yellowness change value (ΔYI)
The test piece obtained by the same method as (4) above was subjected to moisture absorption treatment at 85 ° C. × 85% RH for 168 hours, and then heated at 150 ° C. for 1 minute in an infrared heating reflow oven, The temperature was raised to 265 ° C. at a rate of 100 ° C./min and held for 10 seconds.
The yellowness (YI ₁ ) of the molded product after the heat treatment and the yellowness (YI ₀ ) of the molded product before the heat treatment were measured using a spectrocolor difference meter (SE6000 manufactured by Nippon Denshoku Co., Ltd.), a C light source, The value of the stimulus value XYZ was determined and calculated according to the following formula according to JIS K7313.
YI = 100 (1.2769X−1.0592Z) / Y
Further, the yellowness change value (ΔYI) was calculated by the following equation.
ΔYI = YI ₁ −YI ₀

(6) Reflow resistance About the test piece after the reflow treatment obtained in the above (5), the occurrence of blister (blister), the presence or absence of melting, etc. were observed and evaluated according to the following criteria.
○: No occurrence of blister or melting of the test piece.
Δ: Blister occurred, but the area was 50% or less of the area of the test piece, and the test piece did not melt.
X: A blister having an area exceeding 50% of the area of the test piece was generated or the test piece was melted.

2. Raw materials The raw materials used in Examples and Comparative Examples are shown below.

(1) Polyamide (A)
・ Polyamide (A-1)
4.70 kg of powdered terephthalic acid (TPA) as a dicarboxylic acid component, 0.32 kg of stearic acid (STA) as a monocarboxylic acid component, and 9.3 g of sodium hypophosphite monohydrate as a polymerization catalyst, The reactor was placed in a ribbon blender reactor and heated to 170 ° C. with stirring at a rotation speed of 30 rpm under nitrogen sealing. Thereafter, while maintaining the temperature at 170 ° C. and maintaining the rotation speed at 30 rpm, 2.98 kg of 1,10-decanediamine (DDA) (2.98 kg) heated to 100 ° C. as a diamine component was added using a liquid injection device. Added continuously over 5 hours (continuous liquid injection method) to obtain a reaction product. The molar ratio of raw material monomers was TPA: DDA: STA = 48.5: 49.6: 1.9 (the equivalent ratio of functional groups of the raw material monomers was TPA: DDA: STA = 49.0: 50.0). : 1.0).
Subsequently, the obtained reaction product was polymerized by heating at 250 ° C. and a rotation speed of 30 rpm for 8 hours under a nitrogen stream in the same reaction apparatus to produce a polyamide powder.
Thereafter, the obtained polyamide powder was made into a strand using a twin-screw kneader, and the strand was cooled and solidified by passing it through a water tank, and was cut with a pelletizer to obtain polyamide (A-1) pellets.

・ Polyamide (A-2) to (A-4)
Polyamides (A-2) to (A-4) were obtained in the same manner as polyamide (A-1) except that the resin composition was changed as shown in Table 2.

Table 2 shows the resin compositions and characteristic values of the polyamides (A-1) to (A-4).

(2) Phosphorus flame retardant (B)
B-1: Phosphinate (Exolit OP1230 manufactured by Clariant)
B-2: Hexaphenoxycyclotriphosphazene (Ravitor FP-100 manufactured by Fushimi Pharmaceutical Co., Ltd.)

(3) Fibrous reinforcement (C)
C-1: Glass fiber (03JAFT692 manufactured by Asahi Fiber Glass Co., Ltd.), average fiber diameter 10 μm, average fiber length 3 mm

(4) Flame retardant aid (D)
D-1: Melamine polyphosphate (Melpur 200/70 manufactured by BASF)
D-2: zinc borate 4ZnO.B ₂ O ₃ .H ₂ O (Firebrake 415, manufactured by Borax)

(5) Phosphorous antioxidant (E)
E-1: Tetrakis (2,4-di-tert-butylphenyl) 4,4′-biphenylene-di-phosphonite (Clariant's Hostanox P-EPQ)

(6) Talc (F)
・ F-1: Talc (MSZ-C, manufactured by Nippon Talc Co., Ltd., average particle size 11 μm, surface-treated product)

Example 1
100 parts by mass of polyamide (A-1), 3 parts by mass of melamine polyphosphate (D-1), 3 parts by mass of zinc borate (D-2), 0.4 parts by mass of phosphorous antioxidant (E-1) Dry blended, weighed using a loss-in-weight continuous quantitative supply device (CE-W-1 type manufactured by Kubota), and a twin screw extruder with a screw diameter of 26 mm and L / C50 (TEM26SS type manufactured by Toshiba Machine Co., Ltd.) ) To the main supply port (base part) and melt-kneaded. Then, 17.0 parts by mass of the phosphorus-based flame retardant (B-1) and 30 parts by mass of the glass fiber (C-1) are supplied from the side feeder 1 and further kneaded, and then further from the side feeder 1. From the side feeder 2 installed on the downstream side, 17.0 parts by mass of the phosphorus-based flame retardant (B-1) and 30 parts by mass of the glass fiber (C-1) were supplied. All the side feeders were installed on the downstream side of the first kneading part for melting the polyamide (A-1) in the same-direction twin-screw extruder. Further, nitrogen gas was passed through the quantitative supply device, the main supply port of the extruder, and the side feeder, and the oxygen concentration was maintained at 1% or less. After the polyamide resin composition was taken up from the die in a strand shape, the polyamide resin composition was cooled and solidified through a water tank, and was cut with a pelletizer to obtain polyamide resin composition pellets. The barrel temperature setting of the extruder was (melting point−5 ° C.) to (melting point + 15 ° C.), the screw rotation speed was 250 rpm, and the discharge amount was 25 kg / h.

Examples 2 to 11 and Comparative Examples 1 to 6
Except that the composition of the resin composition, the number of side feeders installed, and the addition amount of the phosphorus-based flame retardant (B) and the fibrous reinforcing material (C) per place were changed as shown in Tables 3 and 4, Examples The same operation as 1 was performed to obtain polyamide resin composition pellets.

Various evaluation tests were performed using the obtained polyamide resin composition pellets. The results are shown in Tables 3 and 4.

The resin compositions of the examples had low yellowness, excellent heat resistance, mechanical properties, and flame retardancy, excellent heat resistance discoloration, and low yellowness change values after reflow treatment.
Since the resin compositions of Examples 1 and 2 have a higher melting point of polyamide (A) than Examples 3 and Comparative Example 1, they have excellent reflow resistance, no blistering, and after the reflow process. Also maintained the shape of the molded body.
In Example 4 in which talc (F) was added to the resin composition of Example 3, the generation of blisters was suppressed and the shape of the molded product was maintained after the reflow process.
In the resin composition of Example 1, the phosphorus-based flame retardant (B) was a phosphinate, and was excellent in flame retardancy as compared with Example 8 (phosphazene compound).
Since the resin composition of Comparative Example 2 did not contain the phosphorus-based flame retardant (B), it was poor in flame retardancy.
Since the resin compositions of Comparative Examples 3 to 6 were produced in such a manner that the amount of the phosphorus flame retardant (B) added per one side feeder exceeded 20 parts by mass with respect to 100 parts by mass of the polyamide (A), the polyamide Deterioration was caused, the yellowness was high, the heat discoloration was inferior, and the yellowness change value after the reflow treatment was large.

Claims (11)

1. It contains 100 parts by mass of a polyamide (A) having a melting point of 270 to 350 ° C. and 10 to 80 parts by mass of a phosphorus flame retardant (B), and has a yellowness (YI ₀ ) of 3.0 or less. A polyamide resin composition.
2. 2. The polyamide resin composition according to claim 1, wherein the yellowness change value (ΔYI) after reflow treatment at 265 ° C. is 12.0 or less.
3. The polyamide resin composition according to claim 1 or 2, wherein the phosphorus-based flame retardant (B) is a phosphinate and / or a diphosphinate.
4. 4. The polyamide resin composition according to claim 3, wherein the phosphinate is a compound represented by the following general formula (I) and the diphosphinate is a compound represented by the following general formula (II).
   

   

   

   (Wherein R ¹ , R ² , R ⁴ and R ⁵ each independently represents a linear or branched alkyl group having 1 to 16 carbon atoms or a phenyl group. R ³ represents a linear or branched group. The chain represents an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylalkylene group, or an alkylarylene group, and M represents a calcium ion, an aluminum ion, a magnesium ion, or a zinc ion. Is 1 or 3. n, a, and b are integers satisfying the relational expression 2 × b = n × a.)
5. The polyamide resin composition according to any one of claims 1 to 4, further comprising 5 to 140 parts by mass of a fibrous reinforcing material (C).
6. The polyamide resin composition according to any one of claims 1 to 5, further comprising 0.1 to 20 parts by mass of talc (F).
7. A method for producing the polyamide resin composition according to any one of claims 1 to 6, wherein in the melt-kneading of the polyamide (A) and the phosphorus-based flame retardant (B), the melt kneader has at least one side. Install the feeder, and add the phosphorus-based flame retardant (B) so that the amount of the phosphorus-based flame retardant (B) added per side feeder is 20 parts by mass or less with respect to 100 parts by mass of the polyamide (A). It adds from a side feeder, The manufacturing method of the polyamide resin composition characterized by the above-mentioned.
8. A method for producing a polyamide resin composition according to claim 5, wherein the fibrous reinforcing material (C) is added in a plurality of times in the melt-kneading of the resin composition. Manufacturing method.
9. The method for producing a polyamide resin composition according to claim 7 or 8, wherein the polyamide (A) is polymerized before melt kneading, and the polymerization is carried out in an inert gas atmosphere.
10. The method for producing a polyamide resin composition according to any one of claims 7 to 9, wherein the melt kneading of the polyamide (A) and the phosphorus flame retardant (B) is carried out in an inert gas atmosphere.
11. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 6.