JP2003253118A - Fire retardant polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition useful in automobile parts, mechanical parts and electric/electronic parts, which is excellent in high fire retardancy as well as mechanical properties even in thin molded articles. <P>SOLUTION: The fire retardant polyamide composition comprises 100 mass% of a component consisting of (a) 30-85 mass% of a polyamide resin comprising a hexamethylene adipamide unit as the main structural ingredient, (b) 5-50 mass% of an inorganic reinforcing material and (c) 5-40 mass% of a fire retarding agent obtained by a reaction of a phosphoric acid compound and a triazine compound, and (d) 0.03-1 mass% of a blowing agent having a decomposition temperature of higher than a processing temperature of the polyamide resin. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has high rigidity, extremely high flame retardancy, no generation of highly corrosive hydrogen halide gas during combustion, and excellent moldability. The present invention relates to a flame-retardant polyamide resin composition which is preferably used as a component material for components such as automobiles and electrical components in the field of automobiles.

[0002]

2. Description of the Related Art Conventionally, polyamide resin has a high mechanical strength,
Since it has excellent heat resistance, it can be used for automobile parts, machine parts,
It is used in fields such as electrical and electronic parts. In particular, in recent years, the demand level for flame retardancy has become higher and higher in electrical and electronic parts applications, and higher flame retardancy than the inherent self-extinguishing property of polyamide resin is required. Therefore, Underwriters Laboratory UL-94
Many studies have been conducted to improve the flame retardancy level that complies with the V-0 standard. And in these, the method of adding a halogen type flame retardant or a triazine type flame retardant is generally proposed.

For example, addition of a chlorine-substituted polycyclic compound to a polyamide resin (JP-A-48-29846) or a brominated flame retardant such as decabromodiphenyl ether (JP-A-47-7134). Addition of brominated polystyrene (JP-A-51-47044 and JP-A-4-175371), addition of brominated polyphenylene ether (JP-A-54-116054)
JP-A-63-3), addition of brominated cross-linked aromatic polymer (JP-A-63-3
17552), addition of brominated styrene-maleic anhydride polymer (JP-A-3-168246), and the like.
However, it is suspected that halogen-based flame retardants generate corrosive hydrogen halide and smoke during combustion, and emit toxic substances.Therefore, due to these environmental problems, the use of plastic products containing halogen-based flame retardants is restricted. There is a movement to do. For this reason, halogen-free triazine flame retardants have attracted attention and many studies have been made.

For example, a technique of using melamine as a flame retardant (Japanese Patent Publication No. 47-1714), a technique of using cyanuric acid (Japanese Patent Publication No. 50-105744), and a technique of using melamine cyanurate (Japanese Patent Publication No. No. 53-31759) is known. Although the non-reinforced polyamide resin composition obtained by these techniques has a high flame retardance level that complies with UL94V-0 standard, in a composition in which rigidity is increased by strengthening with an inorganic reinforcing material such as glass fiber, However, even if a large amount of a flame retardant is blended, there is a problem of cotton ignition at the time of combustion, which does not conform to the UL94V-0 standard. Further, a technique of using melamine phosphate, which is an intimate flame retardant, in a glass fiber reinforced polyamide resin (Japanese Patent Publication No. 10-505875) has been proposed, but it is not possible to simply blend melamine phosphate to obtain 1 UL for 16-inch (1.6 mm) thin-walled molded products
Although it satisfied the 94V-0 standard, it was not compatible with the UL94V-0 standard for a 1/32 inch (0.8 mm) thin-walled molded product, probably because of poor compatibility with the polyamide resin. Thus, in thin-walled molded products, the appearance of non-halogen-based flame-retardant polyamide resins is strongly desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flame-retardant polyamide resin composition having high rigidity, extremely high flame retardancy and excellent thin-wall moldability.

[0006]

Means for Solving the Problems As a result of intensive studies by the present inventors, a system combining a polyamide resin, an inorganic reinforcing material, and a flame retardant obtained by the reaction of a phosphorus compound and a triazine compound. In addition, it was found that the object of the present invention can be achieved when a specific foaming agent is added, and the present invention has been completed based on this finding. That is, the gist of the present invention is as follows. (A) 30 to 85% by mass of a polyamide resin having a hexamethylene adipamide unit as a main constituent, (b) 5 to 50% by mass of an inorganic reinforcing material, and (c) a reaction between a phosphoric acid compound and a triazine compound. 100 parts by mass of a component comprising 5 to 40% by mass of the obtained flame retardant, and (d) a foaming agent 0.03 having a decomposition temperature equal to or higher than the processing temperature of the polyamide resin.
To 1 part by mass, a flame-retardant polyamide resin composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The polyamide resin (a) used in the present invention is a polyamide containing a hexamethylene adipamide unit as a main constituent component. Here, "having hexamethylene adipamide as a constituent component" means that the hexamethylene adipamide unit is a polyamide resin (a) by mixing or copolymerization.
Means that it has been introduced to. As components other than the hexamethylene adipamide unit, aliphatic polyamides such as polyamide 46, polyamide 6, polyamide 610, polyamide 612, polyamide 11 and polyamide 12, hexamethylene terephthalamide, tetramethylene isophthalamide, hexamethylene isophthalamide, Aromatic polyamides containing aromatic components such as terephthalic acid such as meta-xylylene adipamide, isophthalic acid and xylylenediamine can be used. From the viewpoint of fluidity, a mixed polyamide of polyamide 66 and polyamide 6 is preferable, and in particular polyamide 666 having a relative viscosity of 2.7 to 3.5.
Most preferred is a polyamide consisting of 0 to 100% by weight and 640 to 0% by weight of polyamide 640 with a relative viscosity of 1.5 to 2.3.

In the present invention, the inorganic reinforcing material (b) is (a)-
(C) 5-40 mass% of the total amount of each component is contained. If it is less than 5% by mass, the reinforcing effect as a reinforcing material is poor, and if it exceeds 40% by mass, workability is deteriorated. As the inorganic reinforcing material, glass fiber, carbon fiber, potassium titanate fiber, gypsum fiber, brass fiber, stainless fiber, steel fiber, ceramics fiber, boron whisker fiber, mica, talc, silica, calcium carbonate, kaolin, calcined kaolin, Wollastonite, glass beads, glass flakes,
Examples thereof include fibrous, granular, plate-shaped, or needle-shaped inorganic reinforcing materials such as titanium oxide. You may use these reinforcing materials in combination of 2 or more types. In particular, glass fiber, wollastonite, talc, calcined kaolin and mica are preferably used. The glass fiber can be selected from long fiber type roving, short fiber type chopped strand, milled fiber and the like. As the glass fiber, it is preferable to use a surface-treated glass fiber.

In the present invention, as the flame retardant (c),
The compound obtained by the reaction of the phosphoric acid compound and the triazine compound is 5 with respect to the total amount of the components (a) to (c).
-40 mass% is used. If it is less than 5% by weight, the flame retardancy of the obtained composition becomes insufficient, while if it exceeds 40% by weight, the mechanical properties of the obtained composition are significantly deteriorated.

Examples of the phosphoric acid compound constituting the flame retardant include phosphoric acid, orthophosphoric acid, phosphorous acid, hypophosphorous acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, polyphosphoric acid (so-called condensed phosphorous). Acid) and the like. Of these, phosphoric acid, orthophosphoric acid, metaphosphoric acid, and polyphosphoric acid are preferable, and among these, those using polyphosphoric acid are preferable because of their high effect as flame retardants. The condensation degree of polyphosphoric acid is usually 3 to 50, but the condensation degree is not particularly limited in the present invention.

Examples of the triazine-based compound that constitutes the flame retardant include melamine, melem, and melam. Among them, the one using melamine is preferable because it has a high effect as a flame retardant.

As the flame retardant obtained from the reaction product of the phosphoric acid compound and the triazine compound, melamine polyphosphate is most preferable from the viewpoint of its flame retardant effect.

In the present invention, it is necessary to add a foaming agent (d) having a decomposition temperature above the processing temperature of the polyamide resin. When such a foaming agent is used, the foaming phenomenon does not occur during the processing of the resin composition, so that the component as the foaming agent can be mixed in the polyamide component. Then, when exposed to a temperature higher than the resin processing temperature such as a combustion state, the foaming agent in the resin composition causes foaming, whereby combustion is suppressed and flame retardancy is enhanced. The mixing ratio of the component (d) is 0.03 to 1 part by mass based on 100 parts by mass of the total amount of the components (a) to (c). When the blending ratio of the foaming agent is less than 0.03 parts by mass,
The flame retardancy of the obtained composition becomes insufficient, while even if it exceeds 1 part by mass, the flame retardancy of the obtained composition deteriorates.

The blowing agent used in the present invention is required to have a decomposition temperature higher than the processing temperature of the polyamide resin. In the present invention, since the polyamide mainly composed of hexamethylene adipamide units is used, the decomposition temperature of the foaming agent is
It is usually 280 ° C or higher, preferably 290 ° C or higher, more preferably 300 ° C or higher. When the decomposition temperature of the foaming agent is lower than the processing temperature of the polyamide, a foaming phenomenon occurs during kneading and molding, which makes it impossible to manufacture the resin composition itself and to perform molding processing. A tetrazole-based foaming agent can be used as the foaming agent satisfying the above conditions. A tetrazole type foaming agent means 4 nitrogen atoms and 1 carbon atom.
It is a compound having a 5-membered ring composed of atoms, does not have environmental pollution such as dioxins generated during combustion, and produces only gases such as nitrogen, carbon dioxide and water vapor when decomposed by heating. Among the tetrazole-based compounds, compounds having a large amount of gas generation per 1 g of the compound when the compound is thermally decomposed are preferable in that high flame retardancy is obtained. Examples of such tetrazole compounds include 1H-tetrazole metal salts, amine salts and the like.
H-tetrazole derivative or 5,5'-bis-1
5,5'- such as H-tetrazole metal salt and amine salt
Bis-1H-tetrazole derivatives, 5-methyl-1H-tetrazole metal salts, 5-methyl-1H-tetrazole derivatives such as amine salts, or 5-phenyl-1H-tetrazole metal salts, 5-amines such as amine salts
5 such as phenyl-1H-tetrazole derivative or metal salt or amine salt of 5-amino-1H-tetrazole
-Amino-1H-tetrazole derivative, or 1H-
1H-tetrazole-5-carboxylate derivatives such as metal salts and amine salts of tetrazole-5-carboxylate, and 1H-tetrazol-5-yl-
Guanidine is most preferred. The tetrazole compound includes a 2H-tetrazole derivative which is a tautomer of the 1H-tetrazole derivative, but may be a 2H-tetrazole derivative in the present invention. The tetrazole-based foaming agent in the present invention may be added alone or in combination of two or more kinds.

In the present invention, it is also possible to add an inorganic flame-retardant aid within a range that does not adversely affect the mechanical properties and molding processability. 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 flame-retardant polyamide resin composition of the present invention is not particularly limited as long as the decomposition temperature of the foaming agent is equal to or higher than the processing temperature of the polyamide. A method of melt-kneading using a kneader such as a twin-screw extruder or a kneader can be used. At the time of melt-kneading, a method of side-feeding a flame retardant and a foaming agent is preferable.

The flame-retardant polyamide resin composition of the present invention may contain other components, for example, colorants such as pigments and dyes, and general heat stabilizers for polyamide resins, as long as the object of the present invention is not impaired. A certain copper-based heat stabilizer (for example, copper iodide, copper acetate, etc. in combination with potassium iodide, calcium bromide), an organic heat-resistant agent represented by a hindered phenol-based oxidative deterioration inhibitor, a weather resistance improver, Additives such as nucleating agents, plasticizers, lubricants, antistatic agents, fillers, other resin polymers and the like can be added.

The compositions of the present invention are injection molded, extruded,
By known methods such as blow molding, connectors, coil bobbins, breakers, electromagnetic switches, holders, plugs,
Molded into various molded products for electrical, electronic, and automotive applications such as switches.

[0019]

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples. 1. Raw material 1) Polyamide 66 resin (hereinafter referred to as PA66): 101NC010 manufactured by DuPont (relative viscosity 2.7). 2) Polyamide 6 resin (hereinafter referred to as PA6): Unitika A1015 (relative viscosity 2.05). 3) Melamine polyphosphate: PMP-100 manufactured by Nissan Chemical Co., Ltd. 4) Melam polyphosphate: PMP-200 manufactured by Nissan Chemical Co., Ltd. 5) Tetrazole type foaming agent: BHT-GAT (1H-tetrazole-5 manufactured by Toyo Kasei Co., Ltd.)
-Yl-guanidine), decomposition temperature 312 ℃ (hereinafter, GAT
And ) Toyo Kasei Kogyo BHT (1H-tetrazole), decomposition temperature 263 ° C Toyo Kasei P5T (5-phenyl-1H-tetrazole), decomposition temperature 217 ° C 6) Glass fiber: Nippon Electric Glass Co., Ltd. T -289 (hereinafter GF
And )

2. Evaluation method 1) Relative viscosity The relative viscosity in 98% sulfuric acid was measured according to JIS K6810. 2) The decomposition temperature TGA of the foaming agent was measured and determined based on the temperature-weight loss curve. The temperature at the intersection of the tangent line drawn to the inflection point of this curve and the baseline (substantially straight line in the curve where weight loss is zero) was defined as the decomposition temperature. 3) Tensile strength and tensile elongation Measured according to ASTM D638. 4) Flexural strength and flexural modulus Measured according to ASTM D790. 5) Izod impact value Measured according to ASTM D256. 6) Flame retardancy Measured according to the method of UL94 (standard defined by Under Writers Laboratories Inc., USA). The thickness of the test piece was 1/32 inch (0.8 mm). 7) Fluidity IS100E-i3A injection molding machine manufactured by Toshiba Machine Co., Ltd., width 20 mm, thickness 2
A mm bar flow mold was attached, and the fluidity of the resin composition under the conditions of a resin temperature of 280 ° C., an injection pressure of 50 MPa, and a mold temperature of 100 ° C. was evaluated by the bar flow flow length (unit: mm).
The larger the value, the better the fluidity.

Example 1 50 parts by mass of PA66 was 0.03 parts by mass of CuI and 0.1 parts by mass of KI.
Together with the Kubota continuous constant-current feeder, the same-direction twin-screw extruder with side feeder (Toshiba Machinery TEM-37B
S) was supplied to the main supply port. Further, 25 parts by mass of PMP-100, 0.1 parts by mass of GAT and 25 parts by mass of GF were supplied from the side feeder. Melt kneading at a resin temperature of 280 ° C and a discharge rate of 14 kg / hr. The resin composition drawn in a strand form from a nozzle is passed through a water bath to cool and solidify, cut with a pelletizer, and then dried with hot air at 100 ° C for 12 hours. By doing so, pellets of the resin composition were obtained. Then, the resulting resin composition pellets are injected into an injection molding machine (IS manufactured by Toshiba Machine Co., Ltd.
100E-i3A) was molded at a resin temperature of 280 ° C to prepare various test pieces. These were evaluated for mechanical properties and flame retardancy. The results are shown in Table 1.

Examples 2 to 8 and Comparative Examples 1 to 5 Tables 1 and 2 show the mixing ratios of PA66, PA6, flame retardant, foaming agent and GF.
Pellets were obtained in the same manner as in Example 1 except that the ratio was changed to that shown in Table 1, and various characteristics were examined. In Examples 7 and 8, both two types of polyamide were supplied to the main supply port. The results are shown in Table 1.

[0023]

[Table 1]

In each of Examples 1 to 8, a resin composition having both flame retardancy and mechanical properties in a thin molded product was obtained, and Examples 7 and 8 were particularly excellent in fluidity. On the other hand, in Comparative Example 1, the amount of PMP-100 was outside the range of the present invention, so the flame retardancy was insufficient. In Comparative Example 2, since the foaming agent was not added, the flame retardancy was insufficient. In Comparative Examples 3 to 5, since the foaming agent having a lower decomposition temperature than the processing temperature of the resin was used, foaming was remarkable at the time of kneading the resin composition, pellets were not obtained, and evaluation could not be performed.

[0025]

EFFECTS OF THE INVENTION The polyamide resin of the present invention has both flame retardancy and mechanical properties in a thin-walled molded product, and can be favorably used in applications such as automobile parts, machine parts, electric / electronic parts and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J002 CL001 CL01X CL011 CL03W                       CL031 DA016 DA086 DC006                       DE136 DE186 DE236 DG056                       DH027 DH057 DJ006 DJ016                       DJ036 DJ046 DJ056 DK006                       DL006 DM006 EU029 EU188                       FA016 FA046 FA076 FA086                       FD016 FD137 FD138 FD329                       GN00 GQ00

Claims (6)

[Claims] 1. A polyamide resin comprising (a) a hexamethylene adipamide unit as a main constituent, 30 to 85% by mass,
100 parts by mass of a component (b) 5 to 50% by mass of an inorganic reinforcing material, and (c) 5 to 40% by mass of a flame retardant obtained by the reaction of a phosphoric acid compound and a triazine compound,
(D) A flame-retardant polyamide resin composition comprising 0.03 to 1 part by mass of a foaming agent having a decomposition temperature equal to or higher than the processing temperature of the polyamide resin. 2. The flame-retardant polyamide resin composition according to claim 1, wherein the foaming agent (d) is a tetrazole-based foaming agent. 3. The (a) polyamide resin has a relative viscosity of 2.
The flame-retardant polyamide resin composition according to claim 1 or 2, which comprises 60 to 100% by mass of polyamide 66 resin having 6 to 3.5 and 40 to 0% by mass of polyamide 6 resin having relative viscosity of 1.5 to 2.3. object. 4. The flame retardant according to claim 1, wherein the phosphorus compound constituting the flame retardant (c) is at least one selected from phosphoric acid, orthophosphoric acid, pyrophosphoric acid and polyphosphoric acid. -Resistant polyamide resin composition. 5. The flame-retardant polyamide resin composition according to claim 1, wherein the triazine compound constituting the flame retardant (c) is at least one selected from melam, melem, and melam. 6. The flame-retardant polyamide resin composition according to claim 4 or 5, wherein the flame retardant (c) is melamine polyphosphate.