WO2021205938A1

WO2021205938A1 - Flame-retardant polyamide resin composition

Info

Publication number: WO2021205938A1
Application number: PCT/JP2021/013483
Authority: WO
Inventors: 滝人渋谷; 山田　潤
Original assignee: 東洋紡株式会社
Priority date: 2020-04-08
Filing date: 2021-03-30
Publication date: 2021-10-14
Also published as: JPWO2021205938A1; TW202144496A

Abstract

Provided is a flame-retardant polyamide resin composition suitable for electrical/electronic parts and housing parts that reduces mold corrosion while having high heat resistance and high flame retardancy suited to a reflow soldering process and also has excellent mechanical properties, bleed-out resistance, low water absorption, and fluidity. A flame-retardant polyamide resin composition characterized by containing a semi-aromatic polyamide resin (A), a halogen group-containing flame retardant (B), at least one metal salt flame retardancy promoter (C) selected from the group consisting of zinc stannate, zinc borate, zinc phosphate, calcium borate, and calcium molybdate, an inorganic reinforcing material (D), and a metal oxide comprising an oxide of bismuth (E) in proportions of 20-70 mass%, 5-15 mass%, 0.5-15 mass%, 20-60 mass%, and 0.5-5 mass%, respectively.

Description

Flame-retardant polyamide resin composition

The present invention is excellent in mechanical properties such as toughness, tensile strength, tensile elongation, heat resistance, flame retardancy, low water absorption, bleed-out resistance, and fluidity, and while using a halogen group-containing flame retardant. The present invention relates to a flame-retardant polyamide resin composition in which mold corrosion is reduced because the amount of corrosive gas generated during molding is small.

Polyamide resin has been widely used in textiles for clothing, industrial materials, engineering plastics, etc., taking advantage of its excellent mechanical properties and ease of melt molding. In particular, engineering plastics are not limited to automobile parts and industrial machine parts, but are widely used in various industrial parts, housing parts, electrical and electronic parts, and the like.

With regard to electrical and electronic components, surface mounting methods (flow method, reflow method) have rapidly become widespread in recent years due to the miniaturization of parts, the high density of mounting, the simplification of processes, and the cost reduction associated with the miniaturization of product sizes. There is. In the surface mounting method, since the process atmosphere temperature is equal to or higher than the solder melting temperature (240 to 260 ° C.), the resin used is inevitably required to have heat resistance at the above atmosphere temperature. Further, in the surface mounting process, swelling and deformation of the mounting component due to the water absorption of the resin may become a problem, and the resin used is required to have low water absorption. As a resin that satisfies these characteristics, aromatic polyamides such as 6T-based polyamides are used in surface mount type electrical and electronic components.

On the other hand, depending on the location where the molded product is used and the environment, it is desirable that the polyamide resin used as the raw material has flame retardancy based on the UL-94 standard. In response to such a need, various proposals for imparting flame retardancy to the polyamide resin have been made so far.

For example, Patent Document 1 describes a combination of a halogenated organic compound such as brominated polystyrene, which is a flame retardant, and antimony trioxide, which acts as a flame retardant aid, as a technique for making a polyamide resin flame-retardant. .. Although this technology can impart excellent flame retardancy, its use as a plastic product is being regulated because it uses antimony, a heavy metal that may affect the human body. Further, antimony trioxide has a problem of lacking stability at the processing temperature of high melting point polyamide. Therefore, a flame-retardant resin using a metal salt as an alternative to antimony trioxide has been actively studied. In fact, Patent Document 2 describes an example in which zinc stannate or the like is used as an alternative to antimony trioxide in a semi-aromatic polyamide.

As described above, the use of compounds such as zinc and tin as a substitute metal for antimony as a flame retardant aid is progressing, but in order to impart sufficient flame retardancy to the polyamide resin, a large amount of halogen group-containing flame retardant is used. It is necessary to add to. However, since the flame-retardant resin composition based on the semi-aromatic polyamide resin having a high melting point of 280 ° C. or higher has a very high molding processing temperature, the halogen groups contained in the halogen group-containing flame retardant are being molded. Halogen gas is generated due to partial detachment, and this halogen gas causes a problem that the mold is corroded.

In order to solve the above problems, in Patent Document 3, in the halogen-based flame retardant-containing polyamide 4 and 6 resin composition, specific brominated polystyrene polymerized from a dibrominated styrene monomer and hydrotalcites are combined. However, the mold corrosion has not been sufficiently reduced.

As described above, the conventionally proposed halogen-based flame-retardant polyamide resin composition cannot achieve both high heat resistance and high flame retardancy and reduction of mold corrosion, and can be used while having problems. The current situation is that there is.

Japanese Patent Application Laid-Open No. 1-115956 WO2015 / 056765 Japanese Patent Application Laid-Open No. 6-345963

The present invention was devised in view of the above-mentioned problems of the prior art, and an object of the present invention is to reduce mold corrosion while having high heat resistance and high flame retardancy suitable for a reflow soldering process. Further, it is an object of the present invention to provide a flame-retardant polyamide resin composition suitable for electrical and electronic parts and housing parts, which is excellent in mechanical properties, bleed-out resistance, low water absorption, and fluidity.

As a result of diligent studies to achieve the above object, the present inventor has found that a conventional polyamide resin composition containing a high melting point semi-aromatic polyamide resin, a halogen group-containing flame retardant, and a conventional flame retardant aid has been used. By using a specific metal oxide in addition to the flame retardant aid, the amount of the halogen group-containing flame retardant used can at least achieve high flame retardancy, so that the amount of the halogen group-containing flame retardant used can be reduced. It was found that the amount of halogen gas generated during the molding process can be reduced accordingly, and as a result, all the desired physical properties can be achieved at a high level without causing mold corrosion due to the halogen gas. The present invention has been completed.

The present invention has been completed based on the above findings, and is composed of the following (1) to (8).
(1) At least one selected from the group consisting of semi-aromatic polyamide resin (A), halogen group-containing flame retardant (B), zinc tintate, zinc borate, zinc phosphate, calcium borate, and calcium molybdenate. 20 to 70% by mass, 5 to 15% by mass, and 0.5 of the metal oxide (E) composed of the metal salt-based flame retardant (C), the inorganic reinforcing material (D), and the oxide of bismuth, respectively. A flame-retardant polyamide resin composition containing in the proportions of ~ 15% by mass, 20 to 60% by mass, and 0.5 to 5% by mass.
(2) The semi-aromatic polyamide resin (A) contains 50 mol% or more of a structural unit obtained from an equal amount molar salt of a diamine having 2 to 12 carbon atoms and terephthalic acid, and an amino having 11 to 18 carbon atoms. The flame-retardant polyamide resin composition according to (1), which is obtained by copolymerizing one or a plurality of carboxylic acids or lactams having 11 to 18 carbon atoms.
(3) The semi-aromatic polyamide resin (A) contains 50 to 99 mol% of structural units obtained from (a) an equal amount molar salt of hexamethylenediamine and terephthalic acid, and (b) 11-aminoundecanoic acid or undecane. The flame-retardant polyamide resin composition according to (1) or (2), wherein the constituent unit is 1 to 50 mol% obtained from lactam.
(4) The flame-retardant polyamide resin composition according to any one of (1) to (3), wherein the halogen group-containing flame retardant (B) is brominated polystyrene.
(5) The bromine content of brominated polystyrene is 62 to 72% by mass, the weight average molecular weight is 4000 to 8000, and the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) is 1. The flame-retardant polystyrene resin composition according to any one of (1) to (4), which is 05 to 1.40.
(6) The flame-retardant polyamide resin composition according to any one of (1) to (5), wherein the inorganic reinforcing material (D) is glass fiber.
(7) An electrical and electronic component formed by using the flame-retardant polyamide resin composition according to any one of (1) to (6).
(8) A housing component formed by using the flame-retardant polyamide resin composition according to any one of (1) to (6).

The flame-retardant polyamide resin composition of the present invention has high heat resistance, and by using a specific metal oxide in addition to the conventional flame retardant aid, halogen while maintaining excellent flame retardancy. It is possible to reduce the amount of the group-containing flame retardant used. Therefore, the amount of halogen gas generated from the halogen group-containing flame retardant during the molding process can be reduced, and mold corrosion can be reduced. Furthermore, it has excellent fluidity during molding, can suppress the formation of bleeds on the surface of the molded product in an actual use environment such as high temperature and humidity, and can reduce strength reduction and dimensional change due to water absorption of the polyamide resin. can. Therefore, according to the present invention, it is possible to provide a product that highly satisfies the user needs.

The polyamide resin composition of the present invention is suitable for use in an electric / electronic device, an electric / electronic component mounted on an automobile, or a housing of an electric device. The polyamide resin composition of the present invention can be used for forming, for example, connectors, switches, housings for ICs and LEDs, sockets, relays, resistors, capacitors, coil bobbins, various housing parts, etc. by injection molding. ..

The polyamide resin composition of the present invention is a group consisting of a semi-aromatic polyamide resin (A), a halogen group-containing flame retardant (B), zinc stannate, zinc borate, zinc phosphate, calcium borate, and calcium molybdenate. At least one metal salt-based flame retardant (C) selected from, an inorganic reinforcing material (D), and at least one metal oxidation selected from the group consisting of oxides of bismuth, aluminum, titanium, and iron. The substance (E) is contained in a proportion of 20 to 70% by mass, 5 to 15% by mass, 0.5 to 15% by mass, 20 to 60% by mass, and 0.5 to 15% by mass, respectively.

The polyamide resin composition of the present invention preferably corresponds to surface mounting technology, which is a general manufacturing method in electrical and electronic component applications. Therefore, it is preferable that the melting point measured by the method described in the section of Examples described later is 290 to 350 ° C. Here, the melting point of the polyamide resin composition is the melting peak temperature located on the lowest temperature side among the melting peak temperatures measured by DSC (Differential Scanning Calorimeter) due to the polyamide resin of the polyamide resin composition. Is. The melting point is more preferably 300 ° C. to 340 ° C., and even more preferably 310 to 340 ° C. If the melting point exceeds the above upper limit, the processing temperature required for injection molding the polyamide resin composition of the present invention becomes extremely high, so that the polyamide resin composition is thermally decomposed and the desired performance and appearance cannot be obtained. there is a possibility. Further, when the melting point is less than the above lower limit, the heat resistance in the surface mounting process (230 to 280 ° C.) is insufficient, and defects such as product deformation in the process may occur.

The polyamide resin composition of the present invention is required to be able to stably maintain its strength and product dimensions even after the product absorbs water in an actual use environment as the electrical and electronic parts are miniaturized and the structure is densified. Therefore, it is preferable that the equilibrium water absorption rate in water measured by the method described in the section of Examples described later satisfies 3.0% or less. The equilibrium water absorption rate in water is more preferably 2.5% or less, and further preferably 2.0% or less. If the water absorption in water exceeds the above upper limit, the strength will decrease and the dimensions will change significantly due to water absorption, and blisters will occur in the reflow soldering process, which may cause problems such as insufficient strength of the product and poor assembly. be.

The semi-aromatic polyamide resin (A) has a structural unit composed of a dicarboxylic acid component containing terephthalic acid (TPA) and a diamine component. Examples of the semi-aromatic polyamide (A) include 6T-based polyamides (for example, polyamide 6T / 6I composed of terephthalic acid / isophthalic acid / hexamethylenediamine, polyamide 6T / 66 composed of terephthalic acid / adipic acid / hexamethylenediamine, and terephthal. Polyamide 6T / 6I / 66 consisting of acid / isophthalic acid / adipic acid / hexamethylenediamine, polyamide 6T / M-5T consisting of terephthalic acid / hexamethylenediamine / 2-methyl-1,5-pentamethylenediamine, terephthalic acid / Polyamide 6T / 6 consisting of hexamethylenediamine / ε-caprolactam, polyamide 6T / 4T consisting of terephthalic acid / hexamethylenediamine / tetramethylenediamine), 9T-based polyamide (terephthalic acid / 1,9-nonanediamine / 2-methyl-1) , 8-octanediamide), 10T-based polyamide (terephthalic acid / 1,10-decanediamine), 12T-based polyamide (terephthalic acid / 1,12-dodecanediamine), polyamide composed of sebacic acid / paraxylene diamine, etc. Be done.

Among the above-mentioned semi-aromatic polyamides, the semi-aromatic polyamide resin (A) is a constituent unit obtained from an equimolar salt of diamine having 2 to 12 carbon atoms and terephthalic acid from the viewpoint of melting point and equilibrium water absorption in water. It is preferably obtained by copolymerizing one or more of aminocarboxylic acid having 11 to 18 carbon atoms or lactam having 11 to 18 carbon atoms and containing 50 mol% or more. The content of the structural unit obtained from the equimolar salt of diamine having 2 to 12 carbon atoms and terephthalic acid is more preferably 50 to 98 mol%, and the aminocarboxylic acid having 11 to 18 carbon atoms or the carbon number of carbon atoms. The content of one or more of the 11-18 lactams is more preferably 2-50 mol%.

As the diamine component having 2 to 12 carbon atoms constituting the semi-aromatic polyamide resin (A), an aliphatic diamine having 2 to 12 carbon atoms is preferable. Examples of the aliphatic diamine component having 2 to 12 carbon atoms include 1,2-ethylenediamine, 1,3-trimethylenediamine, 1,4-tetramethylenediamine, 1,5-pentamethylenediamine, and 2-methyl-1. , 5-Pentamethylenediamine, 1,6-hexamethylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 2-methyl-1,8-octamethylenediamine , 1,10-decamethylenediamine, 1,11-undecamethylenediamine, 1,12-dodecamethylenediamine, and these can be used alone or in combination of two or more.

The melting point of the semi-aromatic polyamide resin (A) is preferably 290 ° C. or higher. From this point of view, a semi-aromatic polyamide composed of a structural unit obtained from an equimolar salt of a diamine having 10 or more carbon atoms and terephthalic acid may have a melting point of 290 ° C. or lower, and therefore has a melting point of 290 ° C. or less. A polyamide resin containing 50 mol% or more of a structural unit obtained from an equimolar salt of 2 to 8 diamines and terephthalic acid and having a melting point of 290 ° C. or higher on the lowest temperature side is a preferable embodiment. If the structural unit obtained from the equimolar salt of diamine having 2 to 8 carbon atoms and terephthalic acid is less than 50 mol%, the crystallinity and mechanical properties may be deteriorated.

Further, in the case of a semi-aromatic polyamide composed of a structural unit obtained from an equimolar salt of a diamine having 6 to 10 carbon atoms and terephthalic acid, by containing 55 mol% or more of this structural unit, the melting point on the lowest temperature side is located. It is also possible to use a polyamide resin having a temperature of 290 ° C. or higher, which is a preferable embodiment. The content of the structural unit obtained from the equivalent molar salt of diamine having 6 to 10 carbon atoms and terephthalic acid is more preferably 55 to 98 mol%, and among aminocarboxylic acids or lactams having 11 to 18 carbon atoms. The content of one or more of the above is more preferably 2 to 45 mol%. If the structural unit obtained from the equimolar salt of diamine having 6 to 10 carbon atoms and terephthalic acid is less than 55 mol%, the crystallinity and mechanical properties may be deteriorated.

The semi-aromatic polyamide resin (A) can be copolymerized with other components at a ratio of 50% mol or less in the constituent unit. Examples of copolymerizable diamine components include 1,13-tridecamethylenediamine, 1,16-hexadecamethylenediamine, 1,18-octadecamethylenediamine, 2,2,4 (or 2,4,4)-. Alicyclic diamines such as trimethylhexamethylenediamine, piperazine, cyclohexanediamine, bis (3-methyl-4-aminohexyl) methane, bis- (4,4'-aminocyclohexyl) methane, isophoronediamine. Examples thereof include aromatic diamines such as diamines, metaxylylene diamines, paraxylylene diamines, paraphenylenediamines and metaphenylenediamines, and hydrogenated products thereof.

Examples of copolymerizable acid components include isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, and 2,2'-diphenyldicarboxylic acid, 4 , 4'-Diphenyl ether dicarboxylic acid, 5-sulfonic acid sodium isophthalic acid, 5-hydroxyisophthalic acid and other aromatic dicarboxylic acids, fumaric acid, maleic acid, succinic acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, 1 , 11-Undecanedioic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, 1,18-octadecandioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2 Examples thereof include aliphatic and alicyclic dicarboxylic acids such as -cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid and dimer acid. Examples of copolymerizable components include lactams such as ε-caprolactam, 11-aminoundecanoic acid, undecanelactam, 12-aminododecanoic acid, and 12-lauryllactam, and aminocarboxylic acids having a ring-opened structure thereof. Be done.

Among the above components, a particularly preferable copolymerization component is, as described above, one or more of aminocarboxylic acid having 11 to 18 carbon atoms or lactam having 11 to 18 carbon atoms. By using an aminocarboxylic acid having 11 to 18 carbon atoms or a lactam having 11 to 18 carbon atoms, the melting point and the temperature-increasing crystallization temperature can be adjusted to improve the moldability, and the water absorption rate can be reduced during water absorption. It is possible to improve the trouble caused by the change in physical properties and the change in dimensions, and the fluidity at the time of melting can be improved by introducing a flexible skeleton.

When the copolymerization component is composed of a dicarboxylic acid and a diamine, the melting point may be less than 290 ° C. depending on the combination, which is not preferable.

The semi-aromatic polyamide resin (A) is obtained from (a) 50 to 99 mol% of structural units obtained from the equimolar salts of hexamethylenediamine and terephthalic acid, and (b) 11-aminoundecanoic acid or undecanlactam. It is particularly preferable that the semi-aromatic polyamide resin contains 1 to 50 mol% of the constituent units. At this time, in the semi-aromatic polyamide resin (A), in addition to the constituent unit of (a) and the constituent unit of (b), the constituent unit composed of the above-mentioned copolymerizable component is contained in a proportion of 20 mol% or less. May be. By using the semi-aromatic polyamide (A) composed of such constituents, it is possible to realize excellent moldability in addition to high melting point, low water absorption and high flow rate.

The semi-aromatic polyamide resin (A) can be produced by a conventionally known method, and can be easily synthesized, for example, by subjecting a raw material monomer to a polycondensation reaction. The order of the polycondensation reaction is not particularly limited, and all the raw material monomers may be reacted at once, or some raw material monomers may be reacted first, and then the remaining raw material monomers may be reacted. The polymerization method is not particularly limited, but the process from the preparation of the raw material to the production of the polymer may be carried out in a continuous step, the oligomer is once prepared, and then the polymerization is carried out in another step by an extruder or the like, or the oligomer is solidified. A method such as increasing the molecular weight by phase polymerization may be used. By adjusting the charging ratio of the raw material monomer, the ratio of each structural unit in the synthesized copolymer polyamide can be controlled.

Examples of the catalyst used in producing the semi-aromatic polyamide resin (A) include phosphoric acid, phosphorous acid, hypophosphoric acid or its metal salt, ammonium salt, and ester. Specific examples of the metal species of the metal salt include potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony. Examples of the ester include ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester, decyl ester, stearyl ester, phenyl ester and the like. Further, from the viewpoint of improving melt retention stability, it is preferable to add an alkaline compound such as sodium hydroxide, potassium hydroxide, or magnesium hydroxide.

The relative viscosity (RV) of the semi-aromatic polyamide resin (A) measured at 20 ° C. in 96% concentrated sulfuric acid is preferably 0.4 to 4.0, more preferably 1.0 to 3.0, and further. It is preferably 1.5 to 2.5. As a method for keeping the relative viscosity of the polyamide within a certain range, a means for adjusting the molecular weight can be mentioned.

The acid value and amine value of the semi-aromatic polyamide resin (A) are preferably 0 to 200 eq / ton and 0 to 100 eq / ton, respectively. If the terminal functional group exceeds 200 eq / ton, not only gelation and deterioration are promoted during melt retention, but also problems such as coloring and hydrolysis are caused even in the usage environment. On the other hand, when compounding a reactive compound such as glass fiber or maleic acid-modified polyolefin, the acid value and / or amine value is preferably 5 to 100 eq / ton according to the reactivity and the reactive group.

The semi-aromatic polyamide resin (A) adjusts the terminal group weight and molecular weight of the polyamide by a method of polycondensing by adjusting the molar ratio of the amino group amount and the carboxyl group amount and a method of adding a terminal sealant. be able to. When the molar ratio of amino group amount and carboxyl group amount is polycondensed at a constant ratio, the molar ratio of total diamine to total dicarboxylic acid (diamine / dicarboxylic acid) to be used is 1.00 / 1.10 to 1. It is preferable to adjust to the range of 10 / 1.00.

Examples of the timing for adding the end-capping agent include the time when the raw material is charged, the time when the polymerization starts, the time when the polymerization is delayed, or the time when the polymerization ends. The terminal encapsulant is not particularly limited as long as it is a monofunctional compound having reactivity with an amino group or a carboxyl group at the end of polyamide, but monocarboxylic acid or an acid anhydride such as monoamine or phthalic anhydride, Monoisocyanates, monoacid halides, monoesters, monoalcohols and the like can be used. Examples of the terminal encapsulant include aliphatic products such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutylic acid. Alicyclic monocarboxylic acids such as carboxylic acids and cyclohexanecarboxylic acids, benzoic acids, toluic acids, α-naphthalenecarboxylic acids, β-naphthalenecarboxylic acids, methylnaphthalenecarboxylic acids, aromatic monocarboxylic acids such as phenylacetic acid, maleine anhydride Acid anhydrides such as acid, phthalic anhydride, hexahydrophthalic anhydride, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine and the like. Examples thereof include alicyclic monoamines such as aliphatic monoamines, cyclohexylamines and dicyclohexylamines, and aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine.

The semi-aromatic polyamide resin (A) needs to be present in a proportion of 20 to 70% by mass, preferably in a proportion of 25 to 55% by mass, in the entire polyamide resin composition of the present invention. If the proportion of the semi-aromatic polyamide resin (A) is less than the above lower limit, the mechanical strength is lowered, and if it exceeds the above upper limit, the blending amount of other components is insufficient, and it becomes difficult to obtain the desired effect.

The halogen group-containing flame retardant (B) is blended to impart flame retardancy to the molded product formed of the polyamide resin of the present invention, and has a mass of 5 to 15 in the entire polyamide resin composition of the present invention. It needs to be present in a proportion of%, preferably present in a proportion of 7 to 13% by mass. Examples of the halogen group-containing flame retardant (B) include tetrabromobisphenol A (TBBA), decabromodiphenyl ether (Deca-BDE), tribromofer, hexabromocyclododecane (HBCD), and ethylenebis (tetrabromophthalimide). Included are TBBA carbonate oligomers, TBBA epoxy oligomers, brominated polystyrene, bis (pentabromophenyl) ethane, TBBA-bis (dibromopropyl ether), hexabromobenzene (HBB). In particular, brominated polystyrene is preferable from the viewpoint of environmental safety and stability during processing. More preferably, only brominated polystyrene is used without using other halogen group-containing flame retardants in combination. The brominated polystyrene has a bromine content of 62 to 72% by mass, a weight average molecular weight of 4000 to 8000, and a molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 1.05 to It is preferably 1.40. If the weight average molecular weight is lower than the above range, the thermal stability tends to decrease and the amount of corrosive gas generated during processing tends to increase, and if it exceeds the above range, the fluidity during injection molding tends to be inferior.

The metal salt-based flame retardant (C) is at least one metal compound selected from the group consisting of zinc nitrate, zinc borate, zinc phosphate, calcium borate, and calcium molybdate, and has a halogen group. By combining with the flame retardant (B) contained, it is blended in order to develop the flame retardancy of the flame retardant (B) containing a halogen group to a higher degree. These metal salt-based flame retardant aids are conventionally used flame retardant aids and have a role different from that of the metal oxide (E) described later. In particular, a metal salt-based flame retardant aid mainly composed of zinc nitrate, zinc borate, and zinc phosphate is preferable from the viewpoint of stability and the effect of the present invention.

The blending amount of the metal salt-based flame retardant aid (C) in the polyamide resin composition is 0.5 to 15% by mass, preferably 1.0 to 12% by mass, and more preferably 2.0 to 10% by mass. preferable. If the blending amount of the metal salt-based flame retardant aid (C) is less than the above lower limit, the target high flame retardancy cannot be obtained, and if it exceeds the above upper limit, the physical properties are significantly reduced and continuous compounding is performed. It is not preferable because it may reduce productivity.

The inorganic reinforcing material (D) is blended to improve the moldability of the polyamide resin composition and the strength of the molded product, and at least one selected from the fibrous reinforcing material and the needle-shaped reinforcing material is used. It is preferable to do so. Examples of the fibrous reinforcing material include glass fiber, carbon fiber, boron fiber, ceramic fiber, metal fiber and the like, and examples of the needle-like reinforcing material include potassium titanate whiskers, aluminum borate whiskers, zinc oxide whiskers and carbon dioxide. Calcium whiskers, magnesium sulfate whiskers, wallastnite and the like can be mentioned. As the glass fiber, chopped strands or continuous filament fibers having a length of 0.1 mm to 100 mm can be used. As the cross-sectional shape of the glass fiber, a glass fiber having a circular cross section and a non-circular cross section can be used. The diameter of the circular cross-section glass fiber is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less. Further, a glass fiber having a non-circular cross section is preferable in terms of physical properties and fluidity, but a glass fiber having a circular cross section is preferable in terms of cost. The glass fiber having a non-circular cross section includes those having a substantially elliptical shape, a substantially oval shape, and a substantially cocoon shape in a cross section perpendicular to the length direction of the fiber length, and has a flatness of 1.5 to 8. Is preferable. Here, the flatness is assumed to be a rectangle having the smallest area circumscribing a cross section perpendicular to the longitudinal direction of the glass fiber, the length of the long side of this rectangle is the major axis, and the length of the short side is the minor axis. This is the ratio of major axis / minor axis when The thickness of the glass fiber is not particularly limited, but the minor axis is about 1 to 20 μm and the major axis is about 2 to 100 μm. Further, the glass fibers are preferably used in the form of chopped strands cut into fiber bundles having a fiber length of about 1 to 20 mm. Further, in order to improve the affinity of the fibrous reinforcing material with the polyamide resin, it is preferable to use an organically treated material, a coupling agent treated material, or a coupling agent at the time of melt compounding, and the coupling agent is a silane type. Any of a coupling agent, a titanate-based coupling agent, and an aluminum-based coupling agent may be used, and among them, an aminosilane coupling agent and an epoxysilane coupling agent are particularly preferable.

The blending ratio of the inorganic reinforcing material (D) in the polyamide resin composition needs to be 20 to 60% by mass in order to fully exhibit the mechanical properties. The blending ratio is preferably 23 to 57% by mass, more preferably 25 to 55% by mass. If the blending ratio is less than the above lower limit, the mechanical strength of the molded product is lowered, and if it exceeds the above upper limit, the extrudability and the moldability may be lowered, which is not preferable.

The metal oxide (E) is an oxide of bismuth. The metal oxide (E) is combined with the metal salt-based flame retardant (C) in order to promote the decomposition of the halogen group-containing flame retardant in a temperature range different from that of the metal salt-based flame retardant (C). In a wide combustion temperature range, the halogen group-containing flame retardant can be decomposed and the flame retardant gas can be generated accordingly, and an excellent flame retardant effect can be exhibited. On the other hand, even if the metal oxide (E) is additionally blended, the generation of halogen gas derived from the halogen group-containing flame retardant during the molding process is not promoted. This is because the temperature range in which the metal oxide (E) promotes the decomposition of the halogen group-containing flame retardant is higher than the temperature range in the molding process. Therefore, according to the present invention, by additionally blending the metal oxide (E) in addition to the conventional flame retardant aid, the decomposition of the halogen group-containing flame retardant during combustion is promoted, which is required at the time of combustion. By enabling the generation of flame-retardant gas in a wide combustion temperature range, the flame-retardant effect of the halogen group-containing flame retardant can be fully exhibited. As a result, excellent flame retardancy can be maintained even if the amount of the halogen group-containing flame retardant used is reduced. By reducing the amount of the halogen group-containing flame retardant used, it is possible to reduce the amount of unwanted halogen gas generated from the halogen group-containing flame retardant due to heating during the molding process, effectively reducing mold corrosion. be able to. There are various metal oxides having such an action effect other than bismuth oxide, but if a metal oxide having high hardness is used, the inorganic reinforcing material is broken more than necessary, and from the viewpoint of mechanical properties. Not suitable for. From this point of view, bismuth oxide is extremely suitable.

The blending ratio of the metal oxide (E) in the polyamide resin composition needs to be 0.5 to 5% by mass, preferably 0.5 to 4.5% by mass, and 1 to 4%. More preferably, it is by mass%. If this compounding ratio is less than the above lower limit, the target high flame retardancy cannot be obtained, and if it exceeds the above upper limit, the physical properties may be significantly reduced and the continuous productivity at the time of compounding may be lowered. Not preferred.

In addition to the above components (A) to (E), various additives of the conventional polyamide resin composition for electrical and electronic parts can be added to the polyamide resin composition of the present invention. As additives, drip inhibitor such as tetrafluoroethylene (PTFE), stabilizer, impact improver, mold release agent, slidability improver, colorant, plasticizer, crystal nucleating agent, semi-aromatic polyamide resin ( Examples thereof include polyamides having a composition different from that of A), thermoplastic resins other than polyamides, and the like. The possible blending amounts of these components in the polyamide resin composition are as described below, but the total of these components is preferably 30% by mass or less, more preferably 20% by mass or less in the polyamide resin composition. It is more preferably 10% by mass or less, and particularly preferably 5% by mass or less.

By adopting the composition having the above-mentioned structure, the flame-retardant polyamide resin composition of the present invention can achieve both excellent flame retardancy and reduction of mold corrosion, and can be seen by combining conventional flame retardants. It is possible to suppress the formation of bleeds on the surface of the molded product at a high level under the actual usage environment, and it exhibits fluidity during molding. Furthermore, by using a semi-aromatic polyamide resin (A) characterized by a high melting point and low equilibrium water absorption in water, in addition to high flame retardancy, it has a high melting point and high heat resistance, and its dynamics during water absorption. It is possible to obtain a flame-retardant polyamide resin composition having excellent properties such as suppressing deterioration of properties and dimensional changes, and it is possible to supply a product that highly meets user needs.

The polyamide resin composition of the present invention can be produced by blending each of the above-mentioned constituent components by a conventionally known method. For example, each component may be added during the polycondensation reaction of the semi-aromatic polyamide resin (A), the semi-aromatic polyamide resin (A) and other components may be dry-blended, or a twin-screw screw type extruder may be used. Examples thereof include a method of melt-kneading each component by using.

The polyamide resin composition of the present invention can be molded by conventionally known methods such as extrusion molding, injection molding, and compression molding. Since the polyamide resin composition of the present invention hardly generates halogen gas derived from a halogen group-containing flame retardant during the molding process, the problem of mold corrosion does not occur. The formed molded product is excellent in heat resistance, flame retardancy, and processability, and can be used for various purposes. Specifically, various electrical and electronic parts such as connectors and switches, housing parts, and the like are suitable.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. The measured values described in the examples were measured by the following methods.

(1) Relative Viscosity 0.25 g of the polyamide resin was dissolved in 25 ml of 96% sulfuric acid, and the relative viscosity was measured at 20 ° C. using an Ostwald viscometer.

(2) Melting point (Tm)
Using Toshiba Machine's injection molding machine EC-100, the cylinder temperature is set to the melting point of the resin + 20 ° C, the mold temperature is set to 35 ° C, and a test for UL combustion test with a length of 127 mm, a width of 12.6 mm, and a thickness of 0.8 mmt. The piece was injection molded to prepare a test piece. In order to measure the melting point (Tm) of the obtained molded product, a part of the molded product is weighed in an aluminum pan in an amount of 5 mg, sealed with an aluminum lid, a measurement sample is prepared, and then a differential scanning calorimeter is used. Using (SSC / 5200 manufactured by SEIKO INSTRUMENTS), the temperature was raised from room temperature to 20 ° C./min in a nitrogen atmosphere, and measurements were carried out up to the melting point of the resin + 30 ° C. At that time, among the peaks of endothermic heat due to melting obtained, the peak top temperature observed on the lowest temperature side was defined as the melting point (Tm).

(3) Equilibrium water absorption in water Using an injection molding machine EC-100 manufactured by Toshiba Machine Co., Ltd., the cylinder temperature is set to the melting point of the resin + 20 ° C. and the mold temperature is set to 135 ° C., and a flat plate of 100 mm in length, 100 mm in width and 1 mm in thickness is injected. It was molded to prepare a test piece for evaluation. After annealing this test piece in an atmosphere of 140 ° C. for 2 hours, the weight was measured, and the weight at this time was taken as the weight at the time of drying. Further, the annealed test piece was immersed in hot water at 80 ° C. for 50 hours, and then the weight was measured, and the weight at this time was taken as the weight at the time of saturated water absorption. From the weights at the time of saturated water absorption and drying measured by the above method, the equilibrium water absorption rate in water was obtained from the following formula.
Equilibrium water absorption in water (%) = {(weight during saturated water absorption-weight during drying) / weight during drying} x 100

(4) Tensile strength Using an injection molding machine EC-100 manufactured by Toshiba Machine Co., Ltd., the cylinder temperature was set to the melting point of the resin + 20 ° C. and the mold temperature was set to 135 ° C. Was produced. Using the prepared test pieces, tensile physical properties were evaluated and tensile strength was measured in accordance with ISO 527-1 and ISO 527-1. The tensile strength was judged according to the following criteria.
◯: Tensile strength ≧ 140 MPa
X: Tensile strength <140 MPa

(5) Tensile elongation Using an injection molding machine EC-100 manufactured by Toshiba Machine Co., Ltd., the cylinder temperature was set to the melting point of the resin + 20 ° C. and the mold temperature was set to 135 ° C. Pieces were made. Using the prepared test piece, the tensile physical properties were evaluated and the tensile elongation was measured in accordance with ISO 527-1 and ISO 527-1.

(6) Using a flame-retardant injection molding machine EC-100 manufactured by Toshiba Machine Co., Ltd., the cylinder temperature is set to the melting point of the resin + 20 ° C. and the mold temperature is set to 135 ° C., and the length is 127 mm, the width is 12.7 mm, and the thickness is 0.8 mm. An evaluation test piece was prepared by injection molding. Using this test piece, the evaluation was carried out with 10 test pieces in accordance with the UL-94 vertical combustion test. The total burning time of 5 pieces was calculated from the count of the number of drip ignition occurrences and the burning time of the test pieces that did not drip, and evaluated according to the following criteria.
◯: No drip ignition occurred, and the total burning time of 5 pieces was 50 seconds or less.
X: Drip ignition has occurred, or the total burning time of 5 pieces exceeds 50 seconds.

(7) Mold corrosion resistance Place 10 g of resin pellets in the range of φ900 mm on aluminum foil, place a glass plate with a thickness of 20 mm × 50 mm × 2 mm on the pellets, and place a copper plate with a thickness of 10 mm × 30 mm × 1 mm on it. , Φ900 mm covered with a glass petri dish. This was heat-treated on a hot plate at 330 ° C. for 15 minutes, and then the surface condition of the copper plate was visually observed and evaluated according to the following criteria.
◯: No corrosion. There is no discoloration of the copper plate and there is almost no deposit.
Δ: There is some corrosion. The copper plate turns blue and there is a small amount of deposits.
×: Corroded. The copper plate turns brown and there is a large amount of deposits.

(8) MI (melt flow index)
In accordance with ISO1133, the cylinder temperature was set to 330 ° C. and the load was set to 2.16 kg, and the fluidity evaluation was carried out.

(9) Bleed-out resistance Using Toshiba Machine's injection molding machine EC-100, the cylinder temperature is set to the melting point of the resin + 20 ° C, the mold temperature is set to 135 ° C, and a flat plate of length 100 x width 100 x thickness 1 mm is injected. It was molded and a test piece for evaluation was prepared. After allowing this evaluation test piece to stand in an atmosphere of 80 ° C. and 85% RH (relative humidity) for 200 hours, the state of bleeding on the surface of the test piece was visually confirmed according to the following criteria.
◯: No bleeding was generated.
×: Bleed product is generated.

Synthesis of Semi-Aromatic Polyamide Resin (A) As the semi-aromatic polyamide resin (A) used in Examples and Comparative Examples, the following two types of semi-aromatic polyamide resins (A-1) and (A-2) are used. Synthesized.

<Synthesis of semi-aromatic polyamide resin (A-1)>
50 of 1,6-hexamethylenediamine 7.54 kg, terephthalic acid 10.79 kg, 11-aminoundecanoic acid 7.04 kg, sodium hypophosphate 9 g as a catalyst, acetic acid 40 g as a terminal regulator and ion-exchanged water 17.52 kg. It was charged to a liter autoclave, pressurized with _{N 2} from atmospheric pressure to 0.05 MPa, was relieved and returned to normal pressure. This operation was performed three times to perform N ₂ substitution, and then the mixture was uniformly dissolved at 135 ° C. and 0.3 MPa with stirring. Then, the solution was continuously supplied by a liquid feed pump, the temperature was raised to 240 ° C. by a heating pipe, and heat was applied for 1 hour. Then, the reaction mixture was supplied to the pressurized reaction can, heated to 290 ° C., and a part of water was distilled off so as to maintain the pressure inside the can at 3 MPa to obtain a low-order condensate. After that, this low-order condensate is directly supplied to a twin-screw extruder (screw diameter 37 mm, L / D = 60) while maintaining the molten state, and the resin temperature is 335 ° C. while draining water from three vents. Polycondensation was carried out under melting to obtain a semi-aromatic polyamide resin (A-1). The obtained semi-aromatic polyamide resin (A) had a relative viscosity of 2.02, a melting point of 315 ° C., an acid value of 126 eq / ton, and an amine value of 22 eq / ton.

<Synthesis of semi-aromatic polyamide resin (A-2)>
50 of 1,6-hexamethylenediamine 7.54 kg, terephthalic acid 10.79 kg, 11-aminoundecanoic acid 7.04 kg, sodium hypophosphate 9 g as a catalyst, acetic acid 15 g as a terminal regulator and ion-exchanged water 17.52 kg. It was charged to a liter autoclave, pressurized with _{N 2} from atmospheric pressure to 0.05 MPa, was relieved and returned to normal pressure. This operation was performed three times to perform N ₂ substitution, and then the mixture was uniformly dissolved at 135 ° C. and 0.3 MPa with stirring. Then, the solution was continuously supplied by a liquid feed pump, the temperature was raised to 240 ° C. by a heating pipe, and heat was applied for 1 hour. Then, the reaction mixture was supplied to the pressurized reaction can, heated to 290 ° C., and a part of water was distilled off so as to maintain the pressure inside the can at 3 MPa to obtain a low-order condensate. After that, this low-order condensate is directly supplied to a twin-screw extruder (screw diameter 37 mm, L / D = 60) while maintaining the molten state, and the resin temperature is 335 ° C. while draining water from three vents. Polycondensation was carried out under melting to obtain a semi-aromatic polyamide resin (A-2). The obtained semi-aromatic polyamide resin (A-2) had a relative viscosity of 2.48, a melting point of 315 ° C., an acid value of 98 eq / ton, and an amine value of 34 eq / ton.

Examples 1-9, Comparative Examples 1-9
The components and mass ratios (parts by mass) shown in Table 1 were melt-kneaded at the melting point of each semi-aromatic polyamide resin raw material at a melting point of + 20 ° C. using a twin-screw extruder TEM26SS manufactured by Toshiba Machine Co., Ltd. under the following conditions, and Example 1 -9, Polyamide resin compositions of Comparative Examples 1-9 were obtained. Performance evaluation was performed by the above-mentioned method using the polyamide resin compositions of each Example and Comparative Example. The results are shown in Table 1.
Kneading conditions: Screw rotation speed 200 rpm
Discharge rate 20 kg / h
Glass fiber (GF) is input from the side feeder, and other raw materials are input from the main feeder (MF).

The details of each component shown in Table 1 are as follows.
Semi-aromatic polyamide resin (A)
-Semi-aromatic polyamide resin (A-1) (PA6T / 11 (polyamide 6T / 11), melting point: 315 ° C., relative viscosity: 2.02, acid value 126 eq / ton, amine value 22 eq / ton)
-Semi-aromatic polyamide resin (A-2) (PA6T / 11 (polyamide 6T / 11), melting point: 315 ° C., relative viscosity: 2.48, acid value 98 eq / ton, amine value 34 eq / ton)
Halogen group-containing flame retardant (B)
Bromineized polystyrene (SAYTEX® HP-3010PST manufactured by albemarle, bromine content 68%, Mw: 5100, Mn: 4500, Mw / Mn: 1.14 (polystyrene conversion))
Metal salt flame retardant aid (C)
-Zinc tin (FLAMTALD S (registered trademark) manufactured by Nippon Light Metal Co., Ltd.)
Inorganic reinforcing material (D)
-Glass fiber (manufactured by NEC Glass Co., Ltd., T-275H, circular cross section)
Metal oxide (E)
・ Bismuth oxide (Bi ₂ O ₃ ) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
・ Aluminum oxide (Al ₂ O ₃ ) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
・ Titanium oxide (TiO ₂ ) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
・ Iron oxide (Fe ₂ O ₃ ) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
・ Zinc oxide (ZnO) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
・ Tin oxide (SnO ₂ ) (Wako 1st grade Wako Pure Chemical Industries, Ltd.)
Additives / anti-drip agents: Polytetrafluoroethylene (Polyflon MPA (registered trademark) FA500H manufactured by Daikin Industries, Ltd.)
・ Talc (KCM7500 manufactured by Hayashi Kasei Co., Ltd., particle size 5.8 μm)
-Release agent: Montanic acid ester (LICOLUB (registered trademark) WE 40 manufactured by Clariant AG)
Stabilizer: 3,9-Bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) trademark] -1,1-dimethyl} -2,4,8,10-terraoxaspiro [ 5.5] undecane (ADEKA ADEKA STAB (registered trademark) AO-80)

As is clear from Table 1, all of Examples 1 to 9 satisfying all the requirements of the present invention have high heat resistance (melting point) and high flame retardancy, while the mold corrosiveness is reduced. On the other hand, Comparative Example 1 is an example in which the amount of the halogen group-containing flame retardant (B) blended is increased as compared with Example 1 instead of blending the metal oxide (E), and the flame retardancy is excellent. However, it is inferior in mold corrosion resistance. Comparative Example 2 is an example in which the amount of the halogen group-containing flame retardant (B) is the same as in Example 1 and the metal oxide (E) is not blended, and the mold corrosion resistance is excellent, but the flame retardant. Inferior in sex. Comparative Example 3 is an example in which the amount of the metal oxide (E) blended is too large, and the resin viscosity becomes too small, so that drip behavior occurs during combustion, and the flame retardancy is inferior. Comparative Examples 4 to 8 are examples in which a metal oxide (E) other than the specific metal oxide specified in the present invention is used, and all of them are inferior in flame retardancy. In addition, Comparative Examples 4 and 5 are also inferior in mechanical properties. Comparative Example 9 is an example in which only the halogen group-containing flame retardant (B) and the metal oxide (E) are used in combination without blending the metal salt-based flame retardant (C) which is a conventional flame retardant. , Inferior in flame retardancy.

The flame-retardant polyamide resin composition of the present invention has high heat resistance, and by using a specific metal oxide in addition to the conventional flame retardant aid, halogen while maintaining excellent flame retardancy. It is possible to reduce the amount of the group-containing flame retardant used. Therefore, the amount of halogen gas generated from the halogen group-containing flame retardant during the molding process can be reduced, and mold corrosion can be reduced. Furthermore, it has excellent fluidity during molding, can suppress the formation of bleeds on the surface of the molded product in an actual use environment such as high temperature and humidity, and can reduce strength reduction and dimensional change due to water absorption of the polyamide resin. can. Therefore, according to the present invention, it is possible to industrially advantageously produce a molded product that highly satisfies the user's needs.

Claims

At least one metal selected from the group consisting of semi-aromatic polyamide resin (A), halogen group-containing flame retardant (B), zinc tintate, zinc borate, zinc phosphate, calcium borate, and calcium molybdenate. 20 to 70% by mass, 5 to 15% by mass, and 0.5 to 15% by mass of the salt-based flame retardant (C), the inorganic reinforcing material (D), and the metal oxide (E) composed of the oxide of bismuth, respectively. A flame-retardant polyamide resin composition containing%, 20 to 60% by mass, and 0.5 to 5% by mass.
The semi-aromatic polyamide resin (A) contains 50 mol% or more of a structural unit obtained from an equal amount molar salt of a diamine having 2 to 12 carbon atoms and terephthalic acid, and is an aminocarboxylic acid or an aminocarboxylic acid having 11 to 18 carbon atoms. The flame-retardant polyamide resin composition according to claim 1, wherein one or a plurality of lactams having 11 to 18 carbon atoms are copolymerized.
The semi-aromatic polyamide resin (A) is obtained from (a) 50 to 99 mol% of structural units obtained from the equimolar salts of hexamethylenediamine and terephthalic acid, and (b) 11-aminoundecanoic acid or undecanlactam. The flame-retardant polyamide resin composition according to claim 1 or 2, wherein the constituent unit is 1 to 50 mol%.
The flame-retardant polyamide resin composition according to any one of claims 1 to 3, wherein the halogen group-containing flame retardant (B) is brominated polystyrene.
The bromine content of brominated polystyrene is 62 to 72% by mass, the weight average molecular weight is 4000 to 8000, and the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) is 1.05 to 1. The flame-retardant polyamide resin composition according to any one of claims 1 to 4, wherein the composition is .40.
The flame-retardant polyamide resin composition according to any one of claims 1 to 5, wherein the inorganic reinforcing material (D) is glass fiber.
An electrical and electronic component formed by using the flame-retardant polyamide resin composition according to any one of claims 1 to 6.
A housing component formed by using the flame-retardant polyamide resin composition according to any one of claims 1 to 6.