JP2582878C - - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a flame-retardant polyamide resin composition, and more particularly to a flame-retardant polyamide using an organic halogen compound as a flame retardant. The present invention relates to a flame-retardant polyamide resin composition which suppresses deterioration such as foaming and coloring and has good heat stability. <Conventional technology> Polyamide resins are used in various fields such as automobile parts, electric / electronic parts, and mechanical parts, because of their good mechanical properties, moldability, and chemical resistance.
Of these, in applications to electric and electronic components, there is a strong demand for flame retardancy, and it is necessary to impart even higher flame retardancy to polyamide resins that are inherently self-extinguishing.
It is known to add an organic halogen-based flame retardant for the purpose of imparting flame retardancy to a polyamide resin. For example, a method of adding decabromobiphenyl ether to a polyamide resin (JP-A-47-7134), A method of adding a polycyclic compound (JP-A-48-29846) and a method of adding brominated polystyrene (JP-A-51-47044)
JP-A No. 61-188463), a method of adding a brominated polyphenylene ether (Japanese Patent Publication No. 56-2100), and in particular, a high molecular weight type brominated polystyrene, Polyphenylene ether is preferably used as a flame retardant for polyamide resins because it has few problems such as bleed-out of the flame retardant and excellent heat stability. <Problems to be solved by the invention> However, even in the prior art, even if brominated polystyrene and brominated polyphenylene ether having relatively good heat stability are used, polyamides having a high melting point such as nylon 66 and nylon 46 can be used. When the resin forms a matrix, its melt molding temperature is high,
During the kneading or molding of the flame retardant, there is a problem that generation of off-flavor gas, foaming, coloring of the resin, etc., which are considered to be caused by partial decomposition of the flame retardant, occur. Such decomposed products are considered to contain halogens and halogen compounds, and in addition to having an adverse effect on the resin, also have a serious effect on the equipment such as the molding machine and the mold are easily corroded. There is a strong demand for a method for stabilizing a polyamide resin composition containing a halogen-based flame retardant. The present inventors have studied to obtain a halogen-based flame retardant-containing polyamide resin composition having excellent heat stability without deterioration such as gas generation, foaming, and coloring during melt molding. The present inventors have found that the above objects can be achieved at once by combining a flame retardant, an auxiliary agent and a specific magnesium-based inorganic compound, and have reached the present invention. <Means for Solving the Problems> That is, the present invention provides (A) (a) 30 to 89% by weight of an aliphatic polyamide resin (excluding nylon 46), (b) 0 to 50% by weight of a fibrous inorganic reinforcing material, (C) Bromine content rate 50
70 to 70% by weight, 10 to 35% by weight of brominated polystyrene having a weight average molecular weight of 5,000 or more, and (d) at least one kind of flame retardant auxiliary agent selected from antimony oxide, tin oxide, iron oxide and zinc oxide. 100% by weight of a polyamide resin composition consisting of
B) Magnesium and aluminum-containing inorganic compounds represented by the following general formula 0.01 to 10
An object of the present invention is to provide a flame-retardant polyamide resin composition characterized by adding parts by weight. Mg _1-y Al _y O _{1 + y / 2} (II) (where 0 <y <0.5) The polyamide of the component (a) used in the present invention comprises an amino acid, a lactam, or a diamine and a dicarboxylic acid. Polyamide (excluding nylon 46) as a main component. Specific examples of the constituent components include lactams such as ε-caprolactam, enantholactam, and ω-laurolactam; amino acids such as ε-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid; hexamethylenediamine; Methylenediamine, dodecamethylenediamine, 2,2,4- / 2,2,4-trimethylhexamethylenediamine, 5-methylnonamethyleneazimine, 1,3-bisaminomethylcyclohexane, 1,4-bisaminomethylcyclohexane Diamines such as bis-p-caminocyclohexylmethane, bis-p-aminocyclohexylpropane and isophoronediamine, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecane diacid, 1,4-cyclohexanedicarboxylic acid, and 1,3 -Dicarbo acids such as cyclohexanedicarboxylic acid and dimer acid There is acid. These constituents are subjected to the polymerization alone or in the form of a mixture of two or more kinds, and any of the polyamide homopolymers and copolymers thus obtained can be used in the present invention. Particularly useful polyamides in the present invention are polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), and polyhexamethylene sebacamide (nylon).
610), polyundecaneamide (nylon 11), polydecaneamide (nylon 12
) And mixtures of these polyamides. The polymerization degree of the polyamide used here is not particularly limited, and a 1% concentrated sulfuric acid solution having a relative viscosity at 25 ° C. in the range of 1.5 to 5.0 can be arbitrarily used. Specific examples of the fibrous inorganic reinforcing material of the component (b) used in the present invention include glass fiber, carbon fiber, stainless steel fiber, and potassium titanate whisker. The compounding amount of these reinforcing materials is not more than 50%, and if the compounding amount exceeds 50%, the fluidity of the resulting resin composition is extremely lowered, which is not preferable. The brominated polystyrene of the component (c) used in the present invention is represented by (IV),
It is a brominated polystyrene having a halogen content of 50 to 70% and a weight average molecular weight of 5,000 or more. (Here, m represents an integer of 30 to 1500.) The addition amount of the above-mentioned brominated polystyrene is 10 to 35% by weight, preferably 15 to 30% by weight. If the addition amount is less than 10% by weight, the flame retarding effect is insufficient, which is not preferable.
If the added amount exceeds 35% by weight, the mechanical properties such as the impact resistance of the resin composition decrease, so that it is not preferable. The flame retardant aid used as component (d) in the present invention is selected from antimony trioxide, zinc oxide, ferrous oxide, ferric oxide, stannous oxide and stannic oxide,
These can be used alone or in the form of a mixture of two or more. The compounding amount of the flame retardant aid is 1 to 15% by weight, preferably 3 to 10% by weight. If the amount of the flame retardant aid is less than 1% by weight, the flame retardancy is insufficient, which is not preferable. On the other hand, if it exceeds 15% by weight, the impact resistance is lowered, which is not preferable. The magnesium / aluminum-containing inorganic compound used as the component (B) in the present invention is a metal oxide represented by the general formula (II) and is obtained by calcining hydrotalcites. Here, the hydrotalcites are composite metal compounds represented by the following general formula (I) and have a BET specific surface area of 1 to 25 m.
² / g, preferably ^{2 to 20} m ² / g, and an average particle size of 5 μm or less, preferably 3 μm or less. Mg _1-x Al _x (OH) ₂ (CO ₃ ) _{x / 2} · mH ₂ O (I) (where 0 <x <0.4, m represents 0 or a positive integer) Metal of component (B) The compound is considered to effectively capture the main components of the decomposition of the flame retardant containing a bromine compound. By adding the component (B), gas generation, foaming, and coloring during molding of the polyamide resin composition containing a brominated flame retardant are considered. Is significantly reduced. The amount of the metal compound (B) added is 0.01 to 10 parts by weight, preferably 0.05 to 8 parts by weight, per 100 parts by weight of the polyamide resin composition (A). If the addition amount is less than 0.01 part by weight, the effect of improving heat resistance is insufficient, so that it is not preferable. Even if the addition amount exceeds 10 parts by weight, there is no further improvement effect. Although the method for producing the resin composition of the present invention is not particularly limited, a mixture of a polyamide resin, a reinforcing material, a flame retardant, a flame retardant aid and a metal compound is extruded in a single or twin screw, a Banbury mixer, a kneader, and a mixer. Examples of the method include melt kneading at a temperature of 200 to 350 ° C. using a generally known melt kneader such as a roll, and a method of melt kneading using an extruder is simple and efficient. The order of the melt-kneading is not particularly limited, and a mixture of the above-mentioned predetermined five components may be kneaded at once. A method in which some of the polyamide and other components are melt-kneaded in advance and the remaining components are kneaded. May be taken. <Example> Hereinafter, the present invention will be described in more detail with reference to examples. Various properties described in Examples and Comparative Examples were evaluated by the following methods. (1) Thermal stability: Heat loss was measured at a heating rate of 20 ° C./min using an 8095B1 heating weight analyzer manufactured by Rigaku Denki Co., Ltd. As a guide. (2) Tensile properties: ASTM D638 (3) Bending properties: ASTM D790 (4) Izod impact strength: ASTM S256 (5) Flammability: 5 inches long, 1/2 inch wide, 1/8, 1 / thick A 16/1/32 inch test piece was molded and measured according to the UL-94 standard defined by UNDER WRITERS LA-BORATORIES in the United States. Reference Example 1 74 parts by weight of nylon 66 having a relative viscosity of sulfuric acid of 2.90, 21 parts by weight of brominated polystyrene ("Pyrotech" 68PB) manufactured by Ferro, 5 parts by weight of antimony trioxide and Mg _4.2 A
l ₂ (OH) _12.4 CO2 0.2 parts by weight of hydrotalcite having a BET specific surface area of 18 m ² / g with a composition of CO ₃ was mixed with a Hensiel mixer, and this mixture was supplied to a hopper of a PCM30 twin screw extruder manufactured by Ikegai Co., Ltd. Then, the mixture was melt-kneaded under the conditions of a cylinder temperature of 280 ° C. and a screw rotation speed of 200 rpm, and after cooling the strand, it was pelletized with a pelletizer. The obtained pellet was dried under vacuum at 100 ° C. for 24 hours, and the heat resistance was measured by heat gravimetric analysis. As shown in Table 1, the pellet had a high decomposition temperature and was excellent in heat resistance. Was found to be a resin composition. When injection molding was performed using the dried pellets at a molding machine cylinder temperature of 280 ° C and a mold temperature of 80 ° C, various test pieces with good surface appearance were obtained without troubles such as gas generation, foaming, and coloring. . The properties of the test piece were as shown in Table 1 and were high in practical value, having both flame retardancy and good mechanical properties. Comparative Example 1 Kneading, molding, and mixing were performed in exactly the same manner as in Reference Example 1 except that no hydrotalcite was used.
When the physical properties were evaluated, this product generated gas from the cylinder tip during molding,
The test piece was colored, and stable molding could not be performed. Also, as shown in Table 1, the various physical properties were low in decomposition temperature, insufficient in heat resistance, deteriorated in mechanical properties, and were not practical. 1) Br-PSt: Brominated polystyrene ("Pyrotech" 68PB) <Effect of the Invention> A brominated flame retardant-containing aliphatic polyamide resin composition comprising a polyamide, a reinforcing material, a flame retardant, and a flame retardant auxiliary as in the present invention. By adding a specific magnesium / aluminum compound to nylon (excluding nylon 46), troubles such as gas generation, foaming and coloring caused by partial decomposition of the flame retardant during molding can be effectively suppressed, and heat resistance It has become possible to obtain a flame-retardant polyamide resin composition having good properties.

Claims (1)

Claims (1) (A) (a) aliphatic polyamide resin (excluding nylon 46) 30 to 8
9% by weight, (b) fibrous inorganic reinforcing material 0 to 50% by weight, (c) bromine content 50 to 50%
70% by weight, 10 to 35% by weight of brominated polystyrene having a weight average molecular weight of 5,000 or more, and (d) at least one kind of flame retardant aid 1 selected from antimony oxide, tin oxide, iron oxide, and zinc oxide Polyamide resin composition 10 consisting of 10% by weight
0 parts by weight of (B) 0.0% of a magnesium / aluminum-containing inorganic compound represented by the following general formula:
A flame-retardant polyamide resin composition comprising 1 to 10 parts by weight. Mg _1-y Al _y O _{1 + y / 2} (II) (where 0 <y <0.5)