JP2000297212A - Flame resistant reinforced polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flame resistant reinforced polyamide resin composition highly flame resistant and free from halogen gas generation in combustion and having high rigidity. SOLUTION: This composition comprises (a) 30-87 wt.% of a polyamide resin comprising meta-xylene adipamide as the principal constituent, (b) 8-40 wt.% of an adduct formed from a melamine and phosphoric acid, (c) 5-50 wt.% of an inorganic reinforcing agent and the sum of the prescribed components (a)-(c) is 100 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flame-retardant polyamide resin composition. In particular, the present invention relates to a flame-retardant polyamide resin composition suitably used for parts such as connectors in the electric and electronic fields and electric parts in the automobile field. In particular, the present invention relates to a highly rigid and reinforced flame-retardant polyamide resin composition having extremely high flame retardancy and generating no highly corrosive hydrogen halide gas during combustion.

[0002]

2. Description of the Related Art Conventionally, polyamide resins have a high mechanical strength,
Because of its excellent heat resistance, automotive parts, machine parts,
Used in fields such as electric and electronic components. In particular, in recent years, the demand for flame retardancy has become increasingly higher in electric and electronic parts applications, and a higher degree of flame retardancy is required than the self-extinguishing property inherent in polyamide resins. For this reason, Underwriters Laboratory UL94V
Numerous studies have been made on the enhancement of the flame retardant level that conforms to the -0 standard, and generally, a method of adding a halogen-based flame retardant or a triazine-based flame retardant has been adopted.

For example, addition of a chlorine-substituted polycyclic compound to a polyamide resin (JP-A-48-29846) and addition of a bromine-based flame retardant such as decabromodiphenyl ether (JP-A-47-7134). , Addition of brominated polystyrene (JP-A-51-47044,
175371), addition of brominated polyphenylene ether (Japanese Patent Application Laid-Open No. 54-116054), addition of a brominated crosslinked aromatic polymer (Japanese Patent Application Laid-Open No. 63-317552), brominated styrene-maleic anhydride polymer. Addition of coalescence (JP-A-3-168246) and the like are known.
In particular, a composition in which these halogen-based flame retardants are blended with a polyamide resin reinforced with glass fiber, etc., is used for electrical and electronic parts, especially for connectors mounted or connected to printed laminates due to its high flame retardancy and high rigidity. It has been frequently used for applications. However, halogen-based flame retardants are suspected of generating corrosive hydrogen halide and smoke during combustion and emitting toxic substances, and the use of plastic products containing halogen-based flame retardants has been restricted due to these environmental problems. There is a movement to do. For this reason, halogen-free triazine-based flame retardants have attracted attention and have been studied a lot.
For example, technology using melamine as a flame retardant (Japanese Patent Publication No. Sho 4
7-1714), a technique using cyanuric acid (JP-A-50-105744), and a technique using melamine cyanurate (JP-A-53-31759) are well known. Although the non-reinforced polyamide resin composition obtained by these techniques has a high flame retardant level conforming to the UL94V-0 standard, in a composition reinforced with an inorganic reinforcing material such as glass fiber to increase rigidity, cyanuric acid is used. Even when a large amount of melamine is blended, there is a problem that cotton ignites during combustion and does not conform to the UL94V-O standard. In addition, a technique has been proposed in which melamine phosphate, an intumescent type flame retardant, is used for a polyamide resin reinforced with glass fiber (Japanese Patent Application Laid-Open No. 10-505875). Then 1/16
Inch molded products satisfy the flame retardant standard UL94-V0, but it is difficult to obtain a thin molded product of 1/32 inch that satisfies the UL94V-0 standard, probably because of poor compatibility with polyamide resin. The appearance of non-halogen-based flame-retardant polyamide resin, which not only has difficult workability during kneading but also impairs the appearance of the molded product, and has a good appearance, high rigidity and a thin molded product that meets UL94V-0 standard There is a strong craving.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flame-retardant polyamide resin having a very high flame retardancy, a good appearance and a high rigidity without the generation of highly corrosive hydrogen halide gas during combustion. It is to provide a composition.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when an adduct formed from melamine and phosphoric acid is blended in a system combining an inorganic reinforcing material and a specific polyamide resin. In addition, they have found that the above object can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides (a) 30 to 87% by weight of a polyamide resin containing a metaxylylene adipamide unit as a main component, and (b) an adduct of 8 to 40 formed from melamine and phosphoric acid. % By weight, (c) inorganic reinforcing material 5
~ 50% by weight of each component, and the above-mentioned component (a) ~
(C) is a reinforced flame-retardant polyamide resin composition in which the amount expressed in weight% is 100 weight% in total.

The polyamide resin (a) used in the present invention
Is a polyamide having a metaxylylene adipamide unit as a main component, and is MXD6 nylon and MX.
It refers to a mixed polyamide of D6 nylon and another polyamide. Other specific polyamide resins include aliphatic polyamides such as polyamide 66, polyamide 46, polyamide 6, polyamide 610, polyamide 612, polyamide 11, and polyamide 12, hexamethylene terephthalamide, tetramethylene isophthalamide, and hexamethylene. Examples include aromatic polyamides containing aromatic components such as terephthalic acid and isophthalic acid such as isophthalamide, copolymers of these polyamides, and mixed polyamides. In particular, from the viewpoint of obtaining high flame retardancy and excellent molded article appearance in a thin molded article, a copolymer of MXD6 nylon and 70 to 98% by weight of a polyamide 66 unit and 2 to 30% by weight of a polyamide 6I unit (polyamide 66) / 6
The polyamide mixed with (I) is most preferable in view of the flame retardancy, heat resistance, appearance of the molded article and moldability of the thin molded article. The proportion of this mixed polyamide is MXD6 40-10
0% by weight, 60 to 0% by weight of polyamide 66 / 6I, polyamide 66 and polyamide 6I are preferred from the viewpoint of improving the flame retardancy. The polyamide resin may have a molecular weight within a range in which it can be molded. In particular, a polyamide resin having a sulfuric acid relative viscosity of 1.6 to 3.5 as specified in JIS K6810 has good molding fluidity and high degree of flowability. It is particularly preferable because a high flame retardant level can be maintained.

The adduct formed from melamine and phosphoric acid used in the present invention (hereinafter abbreviated as melamine adduct)
(B) is surprisingly said that when used in combination with an inorganic reinforcing agent such as glass fiber, a higher flame retardant effect is exhibited as compared with a conventional triazine flame retardant represented by melamine cyanurate. It has a working effect. Especially MXD6
When the adduct is blended with a copolymer of Nylonto, polyamide 66 and polyamide 6I and / or a mixed polyamide resin, a higher level of flame retardant effect is exhibited.

The phosphoric acid constituting the melamine adduct used as a flame retardant in the present invention is specifically orthophosphoric acid,
Examples thereof include phosphorous acid, hypophosphorous acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, and the like. Particularly, an adduct using orthophosphoric acid has a high effect as a flame retardant, and is preferred.
The melamine adduct used as the flame retardant of the present invention means a melamine phosphate which is an adduct formed from substantially equimolar amounts of melamine and the above-mentioned phosphoric acid, and some acid functional groups are partially free. It may be in the state of. Such a melamine adduct is obtained by, for example, forming a mixture of melamine and the above-mentioned phosphoric acid into a water slurry, mixing well to form both adducts in fine particles, and then filtering, washing and drying the slurry. It is a powder obtained by pulverizing the solid material. The mechanical strength of the molded product obtained by molding the finally obtained composition of the present invention, the particle size of the melamine adduct is 100μ in terms of the appearance of the molded product.
m or less, preferably 50 μm or less. The use of a powder having a particle size of 0.5 to 20 μm is particularly preferable because not only high flame retardancy is exhibited, but also the strength of a molded article is significantly increased. The melamine adduct does not necessarily have to be completely pure, and some unreacted melamine or phosphoric acid may remain. However, those containing 10 to 18% by weight as a phosphorus atom in the melamine adduct may be used. ,
It is particularly preferable because a phenomenon that a contaminant adheres to a molding die during molding is not observed.

The inorganic reinforcing material (c) used in the present invention is glass fiber, carbon fiber, potassium titanate fiber, gypsum fiber, brass fiber, stainless fiber, steel fiber, ceramic fiber, boron whisker fiber, mica, talc, silica. , Calcium carbonate, kaolin, calcined kaolin, wollastonite, glass beads, glass flakes, titanium oxide, and other fibrous, granular, plate-like, or needle-like inorganic reinforcing materials. These reinforcing materials may be used in combination of two or more. Particularly, glass fiber, wollastonite, talc, calcined kaolin and mica are preferably used. In addition, long fiber type roving as glass fiber,
It can be used by selecting from short fiber type chopped strand, milled fiber and the like. It is preferable to use glass fibers that have been surface-treated for polyamide.

In the polyamide resin composition of the present invention comprising the components (a), (b) and (c), the proportion of the main polyamide resin (a) is 30 to 87% by weight.
Must be within the range. If it is less than 30% by weight, moldability and mechanical properties are impaired, and if it exceeds 87% by weight, flame retardancy and rigidity may be reduced. The proportion of the melamine adduct (b) is 8 to 40% by weight, preferably 10 to
It is in the range of 35% by weight. When the amount of the component (b) is less than 8% by weight, the flame-retardant effect is not sufficient. When the amount is more than 40% by weight, decomposition gas is generated at the time of kneading, and contaminants adhere to a molding die during molding. Occurs. In addition, it also causes a significant decrease in mechanical properties and a deterioration in the appearance of a molded product.

The proportion of the inorganic reinforcing material (c) is 5 to 50% by weight, preferably 10 to 40% by weight. When the content is 5% by weight or less, no manifestation of mechanical strength and rigidity is observed, and when the content is 50% by weight or more, not only the molding processability during extrusion or injection molding is remarkably reduced, but also no quantitative physical property improvement effect is observed. . In the present invention, an inorganic flame retardant can be further added within a range that does not adversely affect the mechanical properties and moldability. Preferred flame retardant aids include magnesium oxide, magnesium hydroxide, aluminum hydroxide, zinc oxide, zinc sulfide, iron oxide, boron oxide, zinc borate, and the like.

The method for producing the reinforced flame-retardant polyamide resin composition of the present invention is not particularly limited, and the polyamide resin, melamine adduct, and inorganic filler are kneaded with a conventional single-screw or twin-screw extruder or kneader. And a method of melting and kneading at a temperature of 200 to 350 ° C. may be used. In the reinforced flame-retardant polyamide resin composition of the present invention, other components, such as a coloring agent such as a pigment and a dye, and copper which is a general heat stabilizer of the polyamide resin, as long as the object of the present invention is not impaired. Heat stabilizers (for example, a combination of copper iodide and copper acetate with potassium iodide and potassium bromide), organic heat stabilizers represented by hindered phenol-based oxidation deterioration inhibitors, weather resistance improvers, nucleating agents And additives such as plasticizers, lubricants and antistatic agents, and other resin polymers.

The composition of the present invention can be prepared by injection molding, extrusion molding,
By a known method such as blow molding, connectors, coil bobbins, breakers, electromagnetic switches, holders, plugs,
It is molded into various molded products for electric, electronic and automotive applications such as switches.

[0015]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. The measurement methods used in Examples and Comparative Examples are shown below. [Measurement method] (1) Flame retardancy; UL94 (Under Write, USA)
rs Laboratories Inc.). The thickness of the test piece was 1
It was obtained by molding using an injection molding machine (manufactured by Toshiba Machine: IS50EP) with / 16 inch and 1/32 inch. (2) Relative viscosity of sulfuric acid The relative viscosity with 98% sulfuric acid was measured according to JIS K6810. (3) Mechanical properties Using an injection molding machine (TOSHIBA MACHINE: IS50EP),
A bending test piece (thickness: 3 mm) of STM D790 was formed, and a bending test was performed by a method in accordance with ASTM D790 to determine bending strength and flexural modulus.

[0016]

Example 1 An equimolar mixture of melamine and orthophosphoric acid was suspended in a 10-fold amount by weight of water, stirred sufficiently at about 100 ° C., and the slurry was filtered to obtain a white cake. Next, the cake was vacuum-dried at 80 ° C. and pulverized to a particle size of 10
A powder of ー 50 μm melamine-phosphoric acid adduct was obtained. The melamine adduct thus obtained (having a phosphorus atom content of 14.
1% by weight) and 20% by weight of sulfuric acid relative viscosity of 2.4
6 nylon 49.5% by weight, sulfuric acid relative viscosity 2.4, polyamide 66 / 6I copolymer (polyamide 66 copolymerization ratio 80% by weight, melting point 241 ° C.) 55% by weight and glass fiber (Asahi Fiberglass Co., Ltd.) 03JA416) 2
Twin screw extruder (TEM3 manufactured by Toshiba Machine Co., Ltd.)
5) Using a cylinder setting temperature of 260 ° C. and a screw rotation speed of 300 rpm, the polyamide resin and the melamine adduct are top-fed, the glass fibers are side-fed and kneaded, taken out into strands, cooled, and then cooled with a cutter. Granulation was performed to obtain pellets. Various characteristics of the obtained pellets were examined by the above-mentioned measuring methods. Table 1 shows the results.
Shown in

[0017]

Examples 2-3 and Comparative Examples 1-2 Pellets were obtained in the same manner as in Example 1 except that the mixing ratios of the polyamide resin, melamine-phosphoric acid adduct and glass fiber were as shown in Table 1, and various characteristics were obtained. Was examined. Table 1 shows the results.

[0018]

Comparative Example 3 The same procedure as in Example 1 was carried out except that melamine cyanurate [MCA-CO manufactured by Mitsubishi Chemical Corporation] was used instead of the melamine-phosphoric acid adduct, and various characteristics were examined. Table 1 shows the results.

[0019]

Example 4 Melamine phosphate having an average particle size of about 3 μm as a melamine adduct [Apinon P- manufactured by Sanwa Chemical Co., Ltd.]
7202], and pellets were obtained in the same manner as in Example 1 to examine various characteristics. Table 2 shows the results.

[0020]

Examples 5-6 As polyamide resins, MXD6 nylon having a sulfuric acid relative viscosity of 2.4 and a polyamide 66 / 6I copolymer having a sulfuric acid relative viscosity of 2.4 (copolymerization ratio of polyamide 66: 80% by weight, melting point: 241 ° C.) Polyamide 66 having a sulfuric acid relative viscosity of 2.4 and polyamide 6 having a sulfuric acid relative viscosity of 2.4
A pellet was obtained in the same manner as in Example 1 except that I was used, and various characteristics were examined. Table 2 shows the results.

[0021]

Comparative Example 4 Sulfuric acid relative viscosity of 2.4 as polyamide resin
Pellets were obtained in the same manner as in Example 1 except that polyamide 6 was used, and various characteristics were examined. Table 2 shows the results.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

The composition of the present invention has extremely high flame retardancy,
A molding material that does not generate highly corrosive hydrogen halide gas during combustion and has excellent mechanical properties, and can be used for applications such as home electric parts, electronic parts, and automobile parts.

Continued on the front page F-term (reference) 4J002 CL01X CL03W CL03X CL031 CL033 CL05X DA017 DA087 DC007 DE137 DE187 DE237 DG057 DJ007 DJ017 DJ037 DJ047 DJ057 DK007 DL007 DM007 EW046 EW066 FA017 FA047 FA077 FA087 FD017 FD020 FD060 FD060 FD020 FD020 FD060 FD060 FD060 FD020

Claims (7)

[Claims] 1. An adduct 8 formed from (a) 30 to 87% by weight of a polyamide resin containing a metaxylylene adipamide unit as a main component, and (b) melamine and phosphoric acid.
-40% by weight, and (c) 5-50% by weight of the inorganic reinforcing material, and the total amount of the components (a)-(c) expressed by weight% is 100% by weight. Flame retardant polyamide resin composition. 2. The method according to claim 1, wherein the polyamide resin (a) is polymethaxylylene adipamide (MXD6 nylon) 40 to 100.
2. A polyamide comprising a copolymer of polyhexamethylene adipamide (polyamide 66) and polyhexamethylene isophthalamide (polyamide 6I) and / or a mixed polyamide of 60 to 0 wt. 3. The flame-retardant polyamide resin composition according to item 1. 3. The polyamide resin (a) comprises 40 to 100% by weight of MXD6 nylon and 60 to 60% of polyamide 66.
The flame-retardant polyamide resin composition according to claim 1, which is a polyamide consisting of: 4. The polyamide resin (a) comprises 40 to 100% by weight of MXD6 nylon and 60 to 0% of polyamide 6I.
The flame-retardant polyamide resin composition according to claim 1, which is a polyamide consisting of: 5. The method according to claim 1, wherein the adduct formed from melamine and phosphoric acid (b) contains 10 to 18% by weight as a phosphorus atom. Flame retardant polyamide resin composition as described 6. The method according to claim 1, wherein the adduct formed from melamine and phosphoric acid (b) has an average particle size of 0.5 to 20 μm. A flame-retardant polyamide resin composition according to any one of the above. 7. The (c) inorganic reinforcing material is a glass fiber,
The flame retardant according to any one of claims 1, 2, 3, 4, 5, and 6, wherein the at least one reinforcement is selected from wollastonite, talc, calcined kaolin, and mica. Polyamide resin composition.