JP3402747B2 - Flame retardant polyamide resin composition, flame retardant tube and flame retardant protector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant polyamide resin composition, and more particularly, the present invention relates to automobiles such as tubes, pipes, connectors and other parts used in a high temperature atmosphere, and electrical parts. The present invention relates to a flame-retardant polyamide resin having excellent moldability, which is suitably used for parts applications.
Further, the present invention relates to a tube and protector which is obtained by molding the flame-retardant polyamide resin composition of the present invention and has excellent heat resistance and flame retardancy for protecting and binding automobile electric wiring used around an engine and the like.

[0002]

2. Description of the Related Art Conventionally, polyamide resins have been used in the fields of automobile parts, mechanical parts, electric parts, etc. because of their excellent mechanical strength and heat resistance. Especially in automobile parts applications, in response to the vehicle fire problem in recent years,
The required level of flame retardancy is increasing, and higher flame retardancy is required than the self-extinguishing property originally possessed by polyamide resins. As a specific example, a modification made of nylon 11, nylon 12, nylon 6 and nylon 66 / ionomer resin for protecting the electrical wiring in an automobile engine room and bundling it to accommodate a bundle of wiring in a tube or protector. Polyamide resin may be used, but in such a usage method, when the electric wiring is short-circuited due to vibration of an automobile or the like, the polyamide resin tube or protector housing the wiring bundle may be burned up. There is a demand for a polyamide resin composition having extremely high flame retardancy.

A number of studies have been made on making a polyamide resin flame-retardant, and generally, a method of adding a halogen-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 brominated flame retardant such as decabromodiphenyl ether (JP-A-47-7134). Addition of brominated polystyrene (JP-A-51-47044, JP-A-4-175371), addition of brominated polyphenylene ether (JP-A-54-116054), addition of brominated cross-linked aromatic polymer Addition (JP-A-63-317552)
JP-A-56-152863), addition of brominated styrene-maleic anhydride polymer (JP-A-3-16)
No. 8246) and the like have been used in combination with flame retardant aids such as antimony oxide.

However, although the polyamide resin composition obtained by these methods has a high flame retardance level,
The tensile elongation and Izod impact strength were low, and the material became extremely brittle, making it unsuitable for use in automotive parts where high reliability is required. Furthermore, the excellent flexibility and molding processability of the polyamide resin are impaired, and there is a big drawback particularly when used for tube applications.

[0006]

The object of the present invention is to provide a flame-retardant polyamide resin composition having extremely high flame retardancy, good mechanical strength and flexibility, and excellent moldability, and the composition. A flame-retardant tube and a protector for protecting and bundling automobile electric wiring formed by molding.

[0007]

As a result of intensive studies, the present inventor achieved the object by combining a polyamide resin with a specific block copolymer, a specific flame retardant and a flame retardant auxiliary. Based on this finding, they have completed the present invention.

That is, the present invention is a polymer comprising (a) a polyamide resin of 40 to 90% by weight and (b) a vinyl aromatic compound polymer block A and an olefin compound polymer block B, wherein 2 to 36% by weight of hydrogenated block copolymer having an unsaturation degree of not more than 20%,
(C) A modified block copolymer in which a molecular unit containing a carboxylic acid group or a derivative group thereof is bonded to the block copolymer in the above (b) 2 to 36% by weight, and (d) the bromine content is 50 to 90% by weight of brominated flame retardant 2 to 40% by weight, and (e) at least one flame retardant aid selected from antimony oxide, sodium antimonate, tin oxide, iron oxide and zinc oxide 20% by weight of the flame-retardant polyamide resin composition, and a flame-retardant tube and protector for protecting and binding automobile electric wiring formed by molding the flame-retardant polyamide resin composition.

Polyamide resin (a) used in the present invention
And 46 nylon, 6 nylon, 66 nylon, 61
Aliphatic polyamides such as 0 nylon, 11 nylon and 12 nylon, such as hexamethylene terephthalamide,
Aromatic polyamides containing aromatic components such as terephthalic acid and isophthalic acid such as tetramethylene isophthalamide and hexamethylene isophthalamide, and copolyamides and mixed polyamides containing these as the main constituents are shown. Preferably, 6 nylon and 66 nylon are characteristically used.

The vinyl aromatic compound polymer block A and the olefin compound polymer block B used in the present invention
The hydrogenated block copolymer (b) consisting of and is obtained by selectively hydrogenating the conjugated diene portion of the block copolymer consisting of the vinyl aromatic compound polymer block and the conjugated diene compound polymer block. It is what is done.

The block copolymer comprising the vinyl aromatic compound polymer block A and the conjugated diene compound polymer block B is a vinyl aromatic compound polymer block (X) or (X ') and a conjugated diene compound block. A block copolymer comprising a compound polymer block (Y) (where X and X ′ may be the same or different) (X-
Y) _n , X-Y-X ', X- (Y-X-Y) _n- X, X
A linear block copolymer represented by-(Y-X) _n- Y (wherein n is an integer of 1 to 10), or a general formula [(Y-X) _n ] _{m + 2-} Z, [(X-Y) _n ] _{m + 2}
-Z, [(Y-X) _n- Y] _{m + 2-} Z, [(X-Y) _n
-X] _{m + 2-} Z (wherein m is an integer of 1 to 4,
Represents a residue of a coupling agent such as silicon tetrachloride or tin tetrachloride, or a residue of an initiator such as a polyfunctional organolithium compound. ) Radial block copolymers represented by

Typical examples of the vinyl aromatic compound used here include styrene, α-methylstyrene, vinylxylene, ethylvinylxylene, vinylnaphthalene and mixtures thereof, and the conjugated diene-based compound is exemplified. , Butadiene, isoprene, 1,3-
Mention may be made of pentadiene or 2,3-dimethylbutadiene, and mixtures thereof. Preferably, the vinyl aromatic compound is styrene and the conjugated diene compound is butadiene.

The terminal blocks of these block copolymers may be the same or different.

The number average molecular weight of these block copolymers is 10,000 to 800,000, preferably 20,0.
It is from 00 to 500,000.

The content of the vinyl aromatic compound in the block copolymer is preferably 10 to 70% by weight, more preferably 10 to 55% by weight. The hydrogenated block copolymer (b) used in the present invention is obtained by selectively hydrogenating the conjugated diene portion of the block copolymer, and is described in, for example, JP-B-42-8704. Method, that is, by hydrogenating the block copolymer in a mixed solvent of n-hexane and cyclohexane by using hydrogen as a catalyst with cobalt naphthenate and triethylaluminum, the aromatic compound of the vinyl aromatic compound block is aerated. A hydrogenated block copolymer is synthesized in which a portion not exceeding 20% of the group double bonds and at least 80% of the aliphatic double bonds of the conjugated diene compound polymer block are hydrogenated.

The unsaturation degree of the block B in the present invention means
It means the ratio of carbon-carbon double bonds contained in the block B, and is usually in the range of not exceeding 20%. This is a nuclear magnetic resonance spectrum (NMR), an infrared absorption spectrum (I
R) and the like instrumental analysis, and iodometric titration method and other chemical analysis.

These hydrogenated block copolymers can be used not only in one kind but also in a mixture of two or more kinds.

The modified block copolymer (c) used in the present invention can be obtained by adding an unsaturated carboxylic acid or its derivative to the hydrogenated block copolymer. Examples of the unsaturated carboxylic acid or its derivative to be added to the hydrogenated block copolymer include maleic acid,
Maleic anhydride, fumaric acid, itaconic acid, acrylic acid,
Crotonic acid, cis-4-cyclohexene-1,2-dicarboxylic acid and its anhydride, endo-cis-bicyclo [2,2,1] -5-heptene-2,3-dicarboxylic acid and its anhydride, maleinimide Etc.
Of these, maleic anhydride is particularly preferable.

The modified block copolymer (c) is obtained by, for example, adding an unsaturated carboxylic acid or a derivative thereof to a hydrogenated block copolymer in a solution state or a molten state with or without a radical initiator. Obtained by The method for producing the modified block copolymer (c) is not particularly limited in the present invention, but the obtained modified block copolymer (c) contains an unfavorable component such as a gel and has a melt viscosity of A manufacturing method that significantly increases and deteriorates workability is not preferable.
A preferable method is to react the hydrogenated block copolymer with the unsaturated carboxylic acid or its derivative in the presence of a radical initiator in an extruder.

The amount of modification of the modified block copolymer (c) is
It is necessary to be 0.1 to 3 parts by weight, and preferably 0.15 to 1.8 parts by weight, per 100 parts by weight of the unmodified hydrogenated block copolymer. When the amount of modification is 0.1 parts by weight or more, the effect as a modified block copolymer is sufficiently obtained, and when the composition is used, sufficient impact resistance is obtained. When the amount of modification is 3 parts by weight or less, deterioration of heat resistance and deterioration of moldability and appearance of the molded product can be prevented. The unsaturated carboxylic acid or its derivative used in the present invention can be used not only in one kind but also in a mixture of two or more kinds.

The brominated flame retardant (d) used in the present invention has a bromine content of 50 to 90% by weight, preferably 55 to 8%.
It is 0% by weight. When the bromine content is 50% by weight or more, the flame retardant effect can be sufficiently obtained, and when the bromine content is 90% by weight or less, there is no fear that bromine will be desorbed during kneading and the moldability will be impaired.

Examples of the brominated flame retardant (d) include brominated polystyrene, brominated cross-linked aromatic polymer, brominated styrene maleic anhydride polymer, brominated polyphenylene ether, brominated epoxy resin, brominated phenoxy resin and the like. Are not limited to these.

Specific examples of the above are Pyrocheck 68PB <registered trademark> and Pyrocheck LM <, manufactured by Ferro.
Registered Trademark>, Great Lakes PDBS-80 <registered trademark>, PDBS-10 <registered trademark>, Manac EBR-370FK <registered trademark>, Great Lakes PO64P <registered trademark>, Maksim F2400
<Registered trademark> and the like. Among them, brominated polystyrene, brominated polyphenylene ether, and brominated crosslinked aromatic polymer are preferable from the viewpoint of heat resistance and non-bleed-out property, and brominated polystyrene and brominated polyphenylene ether are particularly preferable.

The flame retardant aid (e) used in the present invention is
Antimony oxides such as diantimony trioxide, diantimony tetroxide and diantimony pentoxide; sodium antimonate; tin oxides such as tin monoxide and tin dioxide; ferric oxides such as ferric oxide and gamma iron oxide; Zinc oxide; 2ZnO / 3B
Examples thereof include zinc borate represented by ₂ O / 3.5 H ₂ O.

Specific examples of antimony oxide include Patox C <registered trademark>, Patox M <registered trademark>, Apox S <registered trademark>, antimony oxide KU manufactured by Sumitomo Metal Mining Co., Ltd. FS <registered trademark>, Piroguard AN-700, A manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
N-800 and AN-900 <registered trademark> etc. are mentioned.

Examples of sodium antimonate include San Epoch NA-1075 <registered trademark> manufactured by Nissan Chemical Industries, Ltd., sodium antimonate-S manufactured by Nippon Seiko Co., Ltd., and the like.

Specific examples of zinc oxide include Sakai Chemical Co., Ltd.
ZATEX special item <registered trademark>, Toho Zinc Co., Ltd. silver mine A <registered trademark>, and the like.

Specific examples of zinc borate include FIREBRAKE 290 <registered trademark> (Zinc borate ZB2335) manufactured by Borax, USA.

Among these, antimony oxides such as diantimony trioxide, diantimony tetroxide and diantimony pentoxide are preferable from the viewpoint of flame retardancy. These flame retardant aids (e) can be used alone or in combination of two or more.

Further, in order to improve the flame retardant effect, the flame retardant aid (e) has an average particle size of 0.01 to 10 μm.
Is desirable. The flame retardant aid except zinc borate has an average particle diameter of 0.1 to 2 μm, and
More preferably, it is 0.1 to 1.2 μm. If the average particle size is 0.01 μm or more, the handling property is not difficult, and the productivity is not reduced.

In the resin composition of the present invention, the proportion of the main polyamide resin (a) must be in the range of 40 to 90% by weight. Preferably 50-80% by weight
Is. When the amount of the polyamide resin is 40% by weight or more, a remarkable decrease in elastic modulus and heat resistance can be prevented.
When it is at most% by weight, a composition satisfying flame retardancy and molding processability at the same time can be obtained.

In the resin composition of the present invention, it is essential to use the hydrogenated block copolymer (b) and the modified block copolymer (c) together, but the hydrogenated block copolymer (b) It is necessary that the ratio is in the range of 2 to 36% by weight. It is preferably 4 to 30% by weight. When the amount of the hydrogenated block copolymer (b) is 2% by weight or more,
It is possible to prevent a marked decrease in moldability, and it is possible to prevent a decrease in heat resistance when the content is 36% by weight or less.

The proportion of the modified block copolymer (c) needs to be in the range of 2 to 36% by weight. It is preferably 4 to 30% by weight. When the amount of the modified block copolymer (c) is 2% by weight or more, the effect of improving impact resistance is sufficiently obtained, and when the amount is 36% by weight or less, the melt viscosity of the obtained composition is remarkably increased. As a result, it is possible to prevent the problem that the resin pressure fluctuation during tube molding becomes large, and as a result, a tube having a uniform wall thickness cannot be obtained.

The proportion of brominated flame retardant (d) must be in the range of 2-40% by weight. Preferably 5-30
% By weight. When the amount of the brominated flame retardant (d) is 2% by weight or more, the flame retardant effect is sufficiently obtained, and when the amount is 40% by weight or less, the quantitative flame retardant effect is not only recognized but also included in the flame retardant. It is possible to prevent the appearance of a molded article from being defective due to the generation of corrosive gas during kneading or molding due to the volatile oligomer or its decomposed components, and the adhesion of contaminants to the molding die.

The proportion of flame retardant aid (e) must be in the range of 1 to 20% by weight. It is preferably 3 to 15% by weight. This is because if it is 1% by weight or more, it has an effect of suppressing dripping substances generated at the time of combustion, and if it is 20% by weight or less, deterioration of mechanical properties of the flame retardant polyamide resin composition according to the present invention can be prevented. .

The resin composition of the present invention can be produced by an apparatus which is usually used for mixing polymer substances. For example, there may be mentioned a method in which all the components used in the present invention are premixed with a blender or the like, and then the mixture is produced using a known melt-kneader such as a single-screw or twin-screw extruder, a kneader, a Banbury mixer. Further, a flame retardant (d) and a flame retardant aid (e) are side-fed into a molten resin composed of a polyamide resin (a) / hydrogenated block copolymer (b) / modified block copolymer (c). A melt kneading method or a method in which the hydrogenated block copolymer (b) / modified block copolymer (c) is melt-mixed in advance may be used, and the kneading order of each component is not particularly limited.

The resin composition of the present invention contains other components such as pigments, dyes, reinforcing materials, fillers, heat stabilizers, antioxidants, and antioxidants, as long as the moldability and physical properties are not impaired. Weathering agents, core materials, lubricants, plasticizers, antistatic agents, other resins, etc. can be added.

The resin composition of the present invention is subjected to known molding of general thermoplastic resins such as injection molding, extrusion molding and blow molding, and various moldings such as protectors can be obtained by these molding methods.

Next, a tube formed by molding the flame-retardant polyamide resin composition of the present invention will be described.

In producing the tube of the present invention, the molding method is not particularly limited, but extrusion molding or blow molding is generally used. For example, the flame-retardant polyamide resin composition obtained by the method described above is charged into the hopper of an extruder, the resin composition is melted by screw rotation and sent to the screw tip, and a cylindrical parison is extruded from the die. The tube is obtained by cooling. At this time, a corrugated shape can be formed by using a mold as desired. The shape of the tube is not particularly limited, but it is usually formed in a cylindrical shape. Particularly preferred is a corrugated tube, but a tube with slits can also be used.

The tube of the present invention can be used as a conventional tube, and is particularly suitable as a tube used in a high temperature atmosphere in the engine room of an automobile. Furthermore, since the tube of the present invention has a high level of flame retardancy and toughness, it is particularly suitable as a tube for protecting and binding automobile electric wiring.

[0042]

EXAMPLES The present invention will be described in more detail with reference to specific examples. The various properties in the examples were measured as follows.

Flexural strength / flexural modulus: ASTM-D7
I followed 90.

Izod impact strength: ASTM-D25
6 was followed.

Heat distortion temperature (4.6 kg / cm ² ): A
According to STM-D648.

Flame-retardant property: The molded piece was kept horizontal, the flame of the burner was indirectly fired for 15 seconds, the flame was removed, and it was examined whether or not the fire ignited on the molded piece disappeared.

Tube flexibility: The tube was bent 180 ° and the state was observed.

Tube moldability: The presence or absence of fluctuations in the wall thickness of the tube when molded into a tube was visually observed.

In the examples and comparative examples, (a)
Polyamide resin, (b) hydrogenated block copolymer,
As the modified block copolymer (c), the brominated flame retardant (d) and the flame retardant auxiliary (e), those shown below were used.

(A) Polyamide resin nylon 66; Asahi Kasei Kogyo Leona 1402 <registered trademark> (b) Hydrogenated block copolymer Hydrogenated styrene-butadiene copolymer; Asahi Kasei Kogyo Tuftec H1052 <registered trademark>, styrene Ingredient about 20% by weight, unsaturation degree of butadiene block 10% (c) Modified block copolymer Hydrogenated maleic anhydride modified styrene-butadiene copolymer; Asahi Kasei Corporation Tuftec M1953 <registered trademark>, styrene component about 40 % By weight, maleic anhydride addition amount about 1.2 parts by weight (d) brominated flame retardant polydibromophenyl ether; PO64P <registered trademark> manufactured by Great Lakes, bromine content about 62% by weight (e) flame retardant aid Agent Antimony Trioxide; Patox M <registered trademark> manufactured by Nihon Seiko Co., Ltd., average particle size 0.6 μm

Examples 1 to 5 and Comparative Examples 1 to 4 The raw materials were blended in a tumbler type blender in the proportions shown in Table 1, and then a twin-screw extruder (manufactured by Ikegai Iron Works Co., Ltd.) set at a cylinder temperature of 280 ° C. PCM45),
After melt-kneading, it was taken out in a strand form, cooled with water and granulated with a cutter to obtain a pelletized composition. The obtained pellets were molded into a test piece for measuring physical properties with an injection molding machine (TOSHIBA MACHINE IS50EP). Then, various physical properties were measured by the above-mentioned evaluation methods. The results are shown in Table 1. Also, the pellets obtained in the same manner are fed to a 50 mmφ single-screw extruder with a spinneret capable of forming a tube having a wall thickness of 0.5 mm and an outer diameter of 10 mmφ, and when air is extruded, air is blown into the hollow portion. After being introduced into a cylindrical tube, the corrugated tube shown in FIG. 1 was continuously obtained while the tube was taken by a tube taker equipped with a corrugated die. The obtained tube was examined for flexibility and whether or not there was a change in wall thickness. The results are shown in Table 1.

[0052]

[Table 1]

[0053]

Since the composition of the present invention has excellent heat resistance, impact resistance, flexibility and flame retardancy, it can be used for applications such as automobile parts and electric parts used in a high temperature atmosphere.
In particular, the tube obtained from the composition of the present invention can be used as a tube for protecting and binding automobile electric wiring, which is required to have high flame retardancy and heat resistance. Further, the protector obtained by the present invention also has high flame retardancy and impact resistance, and thus is suitable as a protector used in the engine room.

[Brief description of drawings]

FIG. 1 is a view showing a corrugated tube obtained by the present invention.

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Claims (5)

(57) [Claims] 1. A polymer comprising (a) a polyamide resin of 40 to 90% by weight and (b) a vinyl aromatic compound polymer block A and an olefin compound polymer block B, wherein the unsaturation degree of the block B is 1. 2 to 36% by weight of a hydrogenated block copolymer having a content of less than 20%, (c) a modified block in which a molecular unit containing a carboxylic acid group or a derivative group thereof is bonded to the block copolymer of (b) above. Copolymer 2 to 36% by weight, (d) bromine content 50 to 90% by weight
2 to 40% by weight of a brominated flame retardant, and (e) at least one flame retardant aid selected from antimony oxide, sodium antimonate, tin oxide, iron oxide, zinc oxide and zinc borate 1 A flame-retardant polyamide resin composition, characterized in that 2. The brominated flame retardant of (d) is at least one brominated flame retardant selected from brominated polystyrene, brominated polyphenylene ether, and brominated crosslinked aromatic polymer. Item 1. A flame-retardant polyamide resin composition according to item 1 . 3. The amount of the molecular unit containing a carboxylic acid group or a derivative thereof bonded to the modified block copolymer (c) is 0. 1 to 3.0 according to claim 1 or 2 flame-retardant polyamide resin composition, wherein the parts by weight. 4. The flame retardant property according to claim 1.
Characterized by molding a polyamide resin composition
Flame-retardant tube for protecting and binding automobile electric wiring. 5. The flame retardant property according to claim 1.
Characterized by molding a polyamide resin composition
Flame-retardant protector for automobile electric wiring protection and bundling.