JP2007332308A - Flame retardant polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant polyamide resin composition having flame retardancy without impairing strength or rigidity of a high-rigidity reinforced polyamide resin and without using a halogen-based or phosphorus-based flame retardant, further improved in appearance and warpage of molded articles. <P>SOLUTION: The flame retardant polyamide resin composition comprises (A) 35 to 60 mass% of a polyamide resin, (B) 15 to 25 mass% of fibrous hydrated metal reinforcing material and (C) 15 to 50 mass% of the reinforcing materials other than (B). The flexural modulus of the flame retardant polyamide resin composition is preferably more than 10 GPa. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a polyamide resin composition imparted with flame retardancy without using a halogen-based or phosphorus-based flame retardant without impairing the strength and rigidity of the highly rigid reinforced polyamide resin.

  Polyamide resins are widely used in the fields of civil engineering and architecture including automobile parts and electric / electronic parts because of their excellent physical and chemical properties. As a means for imparting flame retardancy to a polyamide resin, it has been well known that a halogen-based flame retardant is conventionally added, but its safety has been questioned, and as a non-halogen-based flame retardant, cyanur is added. Techniques such as a technique using melamine acid (Patent Document 1), a technique using melamine polyphosphate (Patent Document 2), a technique using melamine cyanurate and a phosphorus-containing phenol resin (Patent Document 3) have been proposed. .

However, in order to impart flame retardancy to the polyamide resin, it is necessary to add many of these flame retardants. On the other hand, in order to improve various mechanical properties, many reinforcing materials such as glass fibers are blended. It has become a common practice. For this reason, even if it tries to make a high-rigidity polyamide resin composition having a flexural modulus of 10 GPa or more flame retardant, the blending amount of the reinforcing material is set so as not to impair the workability and various physical properties at the time of compounding and molding. There is a limitation and there is a limit to increasing the rigidity, and a polyamide resin composition having both high rigidity and flame retardancy has not been obtained without using a halogen-based or phosphorus-based flame retardant.
JP-A-53-31759 Japanese National Patent Publication No. 10-505875 Japanese Patent Laid-Open No. 9-296120

The present invention solves the above-mentioned problems, imparts flame retardancy without using a halogen-based or phosphorus-based flame retardant, without impairing the strength and rigidity of the high-rigidity reinforced polyamide resin. An object of the present invention is to provide a flame retardant polyamide resin composition with improved appearance and warpage.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by blending a specific amount of a fibrous hydrated metal reinforcing material with a reinforced polyamide resin. The invention has been reached. That is, the gist of the present invention is as follows.
(1) Polyamide resin (A) 35 to 60% by mass, fibrous hydrated metal reinforcing material (B) 15 to 25% by mass, and other reinforcing material excluding (B) (C) 15 to 50% by mass Flame retardant polyamide resin composition.

(2) The flame-retardant polyamide resin composition according to the above (1), which has a flexural modulus of 10 GPa or more.

  The flame-retardant polyamide resin composition of the present invention combines the strength, rigidity and flame retardancy of high-rigidity reinforced polyamide resin, and further improves the warpage and appearance of the molded product. It is a polyamide resin composition that can be used in a wide range of applications such as the automobile field. In addition, because it does not contain halogen-based or phosphorus-based flame retardants, the environmental load is extremely small and the industrial utility value is extremely high.

Hereinafter, the present invention will be described in detail.
The flame-retardant polyamide resin composition of the present invention comprises a polyamide resin (A) and other reinforcing materials (C) excluding the fibrous hydrated metal reinforcing materials (B) and (B). The resin (A) will be described. As the polyamide resin (A) in the present invention, polycapramide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polycoupleramide / polyhexamethylene adipamide copolymer (nylon) 6/66), polyundecamide (nylon 11), polycapramide / polyundecamide copolymer (nylon 6/11), polydodecamide (nylon 12), polycoupler / polydodecanamide copolymer (nylon 6/12), polyhexamethylene sebacamide (Nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthalamide (nylon) T), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polycoupler / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polycoupleramide / polyhexamethylene isophthalamide copolymer (nylon 6 / 6I) ), Polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polytrimethylhexamethylene terephthalamide (nylon) TMDT), polybis (4-aminocyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-4-aminocyclohexyl) methane dodecamide (nylon di) Chill PACM12), poly-m-xylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), and mixtures thereof and the like can be exemplified. A polyamide resin composition in which layered silicate is dispersed at the molecular level in the polyamide resin can also be used. Among these, nylon 6, nylon 66, and a mixture of these with nylon 6T / 6I are particularly preferable.

  The compounding quantity of the polyamide resin (A) in this invention needs to be 35-60 mass%, Preferably it is 40-55 mass%. When the blending amount of the polyamide resin (A) is less than 35% by mass, not only the processability at the time of compounding and molding is remarkably lowered but also the strength of the composition is lowered, which is not preferable. On the other hand, if it exceeds 60% by mass, the strength and rigidity of the composition become small, which is not preferable.

Next, the fibrous hydrated metal reinforcing material (B) in the present invention is composed of fibrous crystals having an aspect ratio of 10 or more, for example, magnesium sulfate whisker, calcium silicate whisker, sepiolite, fibrous magnesium hydroxide, etc. Is mentioned. These may be used alone or in combination, but the blending amount is required to be 15 to 25% by mass.
If the blended amount of the fibrous hydrated metal reinforcing material (B) is out of this range, the flame retardancy improving effect does not appear, which is not preferable. Non-fibrous hydrated metal compounds are not preferred because they can be expected to have a flame retardant effect but tend to adversely affect strength and rigidity.

  Furthermore, the other reinforcing material (C) except for the above (B) in the present invention may be any material that has a reinforcing effect on strength and rigidity with respect to the polyamide resin, and is generally known, for example, Glass fiber, carbon fiber, silicon carbide fiber, alumina fiber, potassium titanate whisker, aluminum borate whisker, aramid fiber, mica, talc, kaolin, wollastonite, etc. can be mentioned, and these can also be mixed and used . Among these, glass fiber, mica, talc, kaolin, wollastonite, and mixtures thereof can be suitably used in consideration of economy. The compounding quantity of a reinforcing material (C) needs to be 15-50 mass%, Preferably it is 20-40 mass%.

  When the blending amount of the reinforcing material (C) is less than 15% by mass, the strength and rigidity of the composition are lowered. When it exceeds 50% by mass, not only the workability at the time of compounding and molding is remarkably lowered, but also the strength is reduced. Since it falls, it is not preferable.

  The rigidity (flexural modulus) of the flame retardant polyamide resin composition of the present invention is preferably 10 GPa or more, and particularly preferably 12 GPa or more. When the rigidity (flexural modulus) is less than 10 GPa, particularly when it is used as a casing of a portable electronic / electrical device, there may be a problem of deformation such as breakage, twisting, or deflection. . Furthermore, the high rigidity can contribute to the thinning of the molded product, that is, the weight reduction.

  The polyamide resin composition of the present invention has a heat stabilizer, an antioxidant, a pigment, an anti-coloring agent, a weathering agent, a light-proofing agent, a plasticizer, a crystal nucleating agent, a release agent, etc. May be included.

  Examples of the heat stabilizer and the antioxidant include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and mixtures thereof.

  Furthermore, other thermoplastic resins may be mixed in the flame-retardant polyamide resin composition of the present invention as long as the characteristics are not significantly impaired. Examples of the thermoplastic resin to be mixed include polybutadiene, butadiene / styrene copolymer, acrylic rubber, ethylene / propylene copolymer, ethylene / propylene / butadiene copolymer, natural rubber, chlorinated butyl rubber, chlorinated polyethylene and other elastomers. Or modified products of these with maleic anhydride, styrene / maleic anhydride copolymer, styrene / phenylmaleimide copolymer, polyethylene, polypropylene, butadiene / acrylonitrile copolymer, polyvinyl chloride, polyethylene terephthalate, polyacetal, polyfluoride Vinylidene, polysulfone, polyphenylene sulfide, polyether sulfone, phenoxy resin, polyphenylene ether, polymethyl methacrylate, polyether ketone, polycarbonate, polytetrafur Examples include oloethylene and polyarylate.

  Next, the manufacturing method of the flame-retardant polyamide resin composition of this invention is demonstrated. The method of mixing the reinforcing material (C) other than the fibrous hydrated metal reinforcing material (B) and (B) with the polyamide resin (A) is not particularly limited, and the reinforcing materials (B), (C ) May be uniformly dispersed. Specifically, the polyamide resin (A) pellets may be charged from the base of the biaxial extruder and melted, and then the reinforcing materials (B) and (C) may be charged from the side feeder to be pelletized.

  In addition, as a molding method of the flame retardant polyamide resin composition of the present invention, conventionally known molding methods such as extrusion molding, injection molding, press molding and the like can be applied, and injection molding is particularly preferable.

The molded article obtained by the flame retardant polyamide resin composition of the present invention is not only flame retardant but also excellent in strength and rigidity, and further improved in warpage and appearance. It is suitable for applications such as automobile mechanism parts.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited only to an Example. In addition, the raw material used in the Example and the measuring method of a physical property are as follows.
1. Raw material (1) Polyamide resin (A)
PA6: Nylon 6 Unita A1025
PA66: nylon 66 Leona 1200 manufactured by Asahi Kasei Chemicals Corporation
PA6T / 6I: Nylon 6T / 6I X21-F07 manufactured by Mitsubishi Engineering Plastics
(2) Fibrous hydrated metal reinforcement (B)
Magnesium sulfate whisker: Moss Heidi type A made by Ube Materials
(3) Other reinforcing materials except (B) (C)
Glass fiber: CS03FT692 manufactured by Asahi Fiber Glass
Mica: Kuraray Clarite Mica 300D
(4) Non-fibrous hydrated metal compound Magnesium hydroxide: Kisuma 5 manufactured by Kyowa Chemical Industry Co., Ltd.
(5) Melamine cyanurate: MC-440 manufactured by Nissan Chemical Co., Ltd.
2. Measuring method (1) Bending strength (MPa)
The measurement was performed according to the method described in ASTM-D790. It is preferable that it is 200 MPa or more.
(2) Flexural modulus (GPa)
The measurement was performed according to the method described in ASTM-D790. It is preferable that it is 10 MPa or more.
(3) Flame retardancy Measured according to UL94 vertical combustion test. The specimen thickness was 0.8 mm. The flame retardant level is preferably V-2, V-1, or V-0.
(4) Warpage (mm)
A disk-shaped product having a thickness of 1.6 mm and a diameter of 100 mm was placed on a horizontal plate, the maximum height and the minimum height were measured with a gauge, and the difference was taken as the amount of warpage. The value is 0 if there is no complete warping. The amount of warp is preferably 2 mm or less.
(5) Appearance (Glossiness)
A test piece having a size of 50 mm × 90 mm and a thickness of 2 mm was prepared, and the glossiness at an incident angle of 60 degrees was measured with a gloss meter. The glossiness is preferably 70 or more.
Example 1
55 mass% of polyamide resin PA6 is introduced from the base of a twin screw extruder (Toshiba Machine Co., Ltd., TEM-37BS) in which the cylinder temperature is set to 270 to 280 ° C. and the screw speed is set to 200 rpm, and then the side feeder. Then, 20% by mass of magnesium sulfate whisker and 25% by mass of glass fiber were added, extruded into a strand shape, cooled, and then cut to produce pellets.

Using the obtained pellets, various test pieces were injection molded at a cylinder temperature of 280 ° C. and a mold temperature of 100 ° C. using an IS-100 molding machine manufactured by Toshiba Machine Co., Ltd., and used for each test.
(Example 2)
As a polyamide resin (A), melt-kneading was carried out in the same manner as in Example 1 except that PA66 was changed to 24% by mass and PA6T / 6I was changed to 16% by mass, and the reinforcing material (C) was changed to 40% by mass of glass fiber. Injection molding was performed to obtain a test piece.
(Example 3)
Example 1 except that the polyamide resin (A) is a mixture of 30% by mass of PA6 and 15% by mass of PA6T / 6I, and the reinforcing material (C) is changed to 25% by mass of glass fiber and 10% by mass of mica. Then, melt-kneading and injection molding were performed to obtain a test piece.
(Comparative Example 1)
A test piece was obtained by melt-kneading and injection molding in the same manner as in Example 1 except that the fibrous hydrated metal reinforcing material (B) was not used and the glass fiber was changed to 45% by mass.
(Comparative Example 2)
A test piece was obtained by melt-kneading and injection molding in the same manner as in Example 2 except that the fibrous hydrated metal reinforcing material (B) was not used and the glass fiber was changed to 60% by mass.
(Comparative Example 3)
A test piece was obtained by melt-kneading and injection molding in the same manner as in Example 3 except that the fibrous hydrated metal reinforcing material (B) was not used and the glass fiber was changed to 45% by mass.
(Comparative Example 4)
A test piece was obtained by melt-kneading and injection molding in the same manner as in Example 3 except that the magnesium sulfate whisker was changed to 10% by mass and the glass fiber was changed to 35% by mass.
(Comparative Example 5)
A test piece was obtained by melt-kneading and injection molding in the same manner as in Example 3 except that the magnesium sulfate whisker was changed to 30% by mass and the glass fiber was changed to 15% by mass.
(Comparative Example 6)
A test piece was melt-kneaded and injection-molded in the same manner as in Example 1 except that 20% by mass of magnesium hydroxide, which is a non-fibrous hydrated metal compound, was used instead of the fibrous hydrated metal reinforcement (B). Got.

Table 1 shows the evaluation results of the polyamide resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 6.

As is clear from Table 1, the polyamide resin compositions obtained in Examples 1 to 3 have good strength / rigidity and flame retardancy, and have both strength, rigidity and flame retardancy, and further warp. Sex and appearance were also improved.

On the other hand, the polyamide resin compositions obtained in Comparative Examples 1 to 3 in which the fibrous hydrated metal reinforcing material (B) is not blended, Comparative Example 4 in which the blending amount is small, and Comparative Example 5 in which the blending amount is too large are In both cases, although the strength and rigidity were high, the flame retardancy was inferior. In addition, the polyamide resin composition obtained in Comparative Example 6 in which a non-fibrous hydrated metal compound was blended instead of the fibrous hydrated metal reinforcement (B) had improved flame retardancy, The rigidity was low.
(Comparative Example 7)
Under the same conditions as in Example 1, 40 mass% of PA6 and 15 mass% of melamine cyanurate were introduced from the base of the biaxial extruder, and 45 mass% of glass fiber was introduced from the side feeder, but the strands became brittle. Since it could not be pelletized, the physical properties could not be measured.
(Comparative Example 8)
It was melt-kneaded and pelletized in the same manner as in Comparative Example 7 except that melamine cyanurate was changed to 5% by mass and PA6 was changed to 50% by mass.

Using the obtained pellets, injection molding was carried out in the same manner as in Example 1 to obtain a test piece. However, the flame retardancy was not improved and the strength was reduced.

Claims (2)

Flame retardancy comprising 35-60% by mass of polyamide resin (A), 15-25% by mass of fibrous hydrated metal reinforcing material (B), and 15-50% by mass of other reinforcing material (C) excluding (B) Polyamide resin composition.
The flame-retardant polyamide resin composition according to claim 1, which has a flexural modulus of 10 GPa or more.